Viral diseases of poultry. The most common diseases of chickens, their symptoms and treatment

Healthy chickens - consumer safety. The health of pets is the key to a successful household. Successful farming: the health of domestic chickens.

The most common poultry is chicken. Caring for it is not difficult, however, it is important to pay special attention to the health of the bird.

Experts recommend periodically organizing preventive actions. After all, saving sick chickens is quite difficult and expensive. What can chickens get sick from? What are the main signs of disease? How to treat poultry? What is worse for chickens: coccidiosis syndromes or avian influenza? We tried to answer all these questions in the material below.

What can kill your chickens?

Methods for preventing infectious diseases in domestic chickens

The main method of prevention is a balanced diet and good care. Please note that there is a risk of death of young animals that are in the same room with adult chickens. What to do if your bird gets sick:

• It is best to place them in different enclosures.
• To protect against infectious diseases, be sure to include treatment with disinfectants at least once a month in your preventive actions.
• If the bird is sick, first of all it must be placed separately and this procedure must be carried out immediately. Otherwise, the internal organs of the bird will be damaged, and in the worst case, death.
• Moreover, if the symptoms are complex and treatment no longer makes sense, you will have to get rid of this individual by destroying it.

The most common diseases of poultry

Coccidiosis in chickens symptoms that can be detected at home

Distinctive features of coccidiosis symptoms: diarrhea, in the early stages of the disease, the feces are greenish in color with mucus, in an advanced state - dark brown with blood, the young chicken moves poorly and limps. According to external data, the bird has pale earrings, comb and mucous membranes, ruffled feathers. The chickens' recovery is slow. It takes place in two courses, lasting on average three days, followed by a break of two days.

Methods for treating coccidiosis in poultry

The drugs are dissolved in water or mixed with food. Among the medications used to save livestock: norsulfazole, bichonolate, furagin, coccidin, sulfadimezin, sulfadimethotoxin, furazolidone, decox, statil, sakox, ardinone-25, and baycox.

Disease prevention

But prevention doesn’t require much effort and time. The main thing is cleanliness in the chicken coop and cages. You just need to disinfect the chicken coop and equipment; it is best to do this with a solution of soda or bleach and ammonia.

Other dangerous poultry diseases

Regardless of their age, chickens are susceptible to colibacillosis caused by E. coli. In a complex form, the disease occurs in chickens, while in adults it is chronic. This virus is dangerous even for humans, so treatment of birds must begin immediately. When treating, they mainly use medicines for chickens such as biomicion and terramycin.

Smallpox in domestic chickens

There are diseases for which the best solution is to get rid of the bird. Among them - chicken pox. It is impossible to look at photos and pictures of a sick individual without disgust. Due to the disease, yellow so-called pockmarks appear on the comb and earrings. In addition, the hen's eyes and liver are affected. Treatment, as in other cases, can be effective if it is carried out urgently. In its advanced form, the bird cannot be cured and will have to be destroyed, otherwise it can lead to an epidemic in the chicken coop. Smallpox is a viral disease that spreads slowly. This disease has two types:

• cutaneous form,
• diphtheria form.

The first type of disease is characterized by the development of nodular, proliferative skin lesions on parts of the bird’s body without feathers. The mortality rate for the cutaneous form is very low. The second form of the disease affects the mucous membrane of the upper respiratory tract of birds. The probability of mortality among the livestock is very high. Fowlpox viruses infect birds of both sexes (including laying hens), all ages and breeds. The disease is widespread throughout the world.

Smallpox is usually treated with a special vaccine. It is developed from the “chicken embryo” and consists of live, unattenuated laying pox virus. If used incompetently, the virus can cause serious illness in chickens. The vaccine is injected into the wing membrane of four-week-old chickens and laying hens approximately 1-2 months before the expected start of egg production. Chickens can be vaccinated one day after birth. One vaccination provides protection for life.

Bird flu

One of the most merciless is the disease that every person hears - bird flu. Everyone is afraid of him - from a weak bird and even to a strong person. Indeed, today it has more than 15 varieties.

How does it affect chickens? Can they be protected?

Let's look at everything in order. Bird flu symptoms in chickens and roosters can be seen literally from the first days of the disease. First of all, we note that the virus affects the nervous system of birds, chickens experience incoordination of movements, they can fall, stagger, their necks and wings become bent, in addition, there is an increase in temperature to 44 °C, and thirst sets in. Also pay attention to signs of bird flu such as:

• blackening of the comb and earrings,
• hoarse breathing,
• diarrhea,
• convulsions,
• neurosis.

Internal hemorrhages and impaired blood circulation are also possible when the vascular system is damaged, which is caused by the H5N1 influenza subtype. In a mild form, the condition of the feathers in chickens deteriorates and a decrease in egg laying is observed. In this case, the disease goes away even without special human intervention. In the acute form, which is caused by type H5 and H7, a number of external manifestations are observed, treatment is useless.

Is there a way to prevent bird flu?

As scary as it sounds, preventative methods for chickens have not yet been found, and today this virus is incurable in domestic chickens. In order to protect chickens from this terrible scourge, it is recommended isolation of poultry from contact with wild representatives.

Sick birds, as well as those that came into contact with her, are killed to prevent further spread of the virus. Under no circumstances should you eat meat from a sick bird. Therefore, take care of your laying hens so that grief will bypass you.

Newcastle disease, pasteurellosis, pullorosis, salmonellosis

Unfortunately, Newcastle disease is also incurable; it also affects the entire body of the bird. The disease progresses very quickly and eventually the bird dies. Experts advise burning or burying corpses, but be sure to cover them with fresh lime. Another disease to watch out for is pasteurellosis. It is provoked mainly by rodents and chickens that have suffered from this disease. Treatment is carried out using vaccinations. It is characteristic that the infection lives for a long time in droppings, water and feed. The corpses of individuals suffering from pasteurellosis are burned.

What can cause disease in domestic chickens?

Let's sum it up

We looked at the main types of diseases, there are many varieties of them. As you can see, it is important to be vigilant about the cleanliness of the chicken coop, cages, to the surrounding animals and to the behavior of the birds themselves - this is the only way you can protect the chickens and they will delight you with their rapid growth.

Smallpox

Fowl pox is a viral disease of all bird species caused by DNA viruses of the Poxvirus family ( Poxviridae) of the genus Avipoxviruses ( Avipoxvirus). These viruses have a pronounced tropism for the epithelial cells of the skin, respiratory and gastrointestinal tract of birds.

Birds of all ages are affected. Mortality varies from 20 to 100%. The most striking signs of smallpox are difficulty breathing (dyspnea), exhaustion and sudden death. The infection is transmitted by blood-sucking insects and direct contact with sick birds; less commonly, smallpox is transmitted by contact through contaminated food and drinking water.

Smallpox can spread from wild starlings to other species of the starling family kept in captivity. There was a case of death of the entire collection Bali starlings (Leucopsar rothschildi), who came into contact with an infected wild starling.

Clinical signs:

Clinical signs of smallpox in passerine birds vary depending on the virulence of the strain, route of infection and host susceptibility. Canaries (Serinus canaria) And house sparrows (Passer domesticus) are especially susceptible. In these birds, smallpox can occur in the cutaneous form, in the form of septicemia, or in the diphtheroid form. The cutaneous form of smallpox has been noted in a large number of wild passerine birds, in particular in starlings (Sturnus vulgaris), oatmeal (Emberizidae), white-eye (Zosterops lateralis), Australian fourty (Cracticus tibicen), corvids(Corvidae).

House Sparrow ( Passer domesticus) with a cutaneous form of smallpox.

U great sacred lanes (Gracula religiosa intermedia) smallpox disease occurs with low mortality, but with long-term damage to the eyes, earrings and mouth. In this case, proliferative lymphatic conjunctivitis, keratitis, chronic corneal ulcers, discoloration of the eyelids, cataracts, deformation of the eyeball develop, scars form on the head with concomitant feather loss and scalp baldness.

Smallpox lesions on the head and beak of the common mynah ( Acridotheres tristis).

In the tropical zone, a milder form of smallpox is more often observed in canaries and weavers, but pandemics of a particularly virulent form of the virus occur with high mortality in birds kept in outdoor aviaries and aviaries, especially in areas with a large number of mosquitoes and mosquitoes.

In this video, Dr. Ross Perry is the legendary veterinarian, opened - shows Australian magpie (Cracticus tibicen) sick with smallpox. Pay attention to the growths (bumps) on the bird's feet and the condition of the beak.

U grey-headed bullfinches (Pyrrhula erythaca) fowlpox virus causes the formation of tumor-like lesions on the scalp and inside the beak.

Among captive passerines, avian pox is a septicemic problem occurring primarily in canaries and other members of the canary finch genus ( Serinus). This disease often has a pronounced seasonality and develops in birds most often in autumn and winter. In sick birds, smallpox can occur in the cutaneous, diphtheric or septicemic form. The septicemic or respiratory form is the cause of high mortality, as it leads to severe tracheitis and bronchitis.

Clinical picture of smallpox in canaries. Loss of feathers on the head, dermatitis, blepharitis, lacrimation. .

In canaries, smallpox can occur as a pandemic with 100% death of the population. Sick canaries are lethargic (apathetic), the plumage is ruffled, the birds breathe with an open beak; without treatment, death occurs on the second or third day. The chronic course of infection in canaries develops with conjunctivitis, blepharitis and lacrimation; these signs appear several days before the formation of characteristic skin lesions around the eyes and beak. When the mucous membrane of the trachea and bronchi is damaged, blockage of the respiratory tract develops, leading to the death of the bird. At autopsy, suddenly dead birds show clouding of the walls of the air sacs and pneumonia with proliferative necrotizing bronchitis. In birds with a subacute form of the disease, proliferative skin lesions are observed; histological analysis of the affected tissues reveals typical intracytoplasmic inclusion bodies in the cells of the epidermis and respiratory epithelium.

Diagnosis and differential diagnosis:

A preliminary diagnosis is made based on clinical signs, characteristic skin lesions around the eyes, beak, and paws. The final diagnosis is made after isolation of the virus or histological detection of eosinophilic intracellular inclusion bodies in epithelial cells, followed by electron microscopy or other methods of identifying the pathogen.

Histological specimen of wood accentor skin affected by smallpox.

PCR primers are available in some countries to diagnose smallpox, and the virus can be isolated quite easily from chicken embryos.

The differential diagnosis includes infections caused by Candida spp. and Trichomonas, but it must be borne in mind that all of these infections can complicate the primary viral disease. It is also necessary to exclude vitamin A deficiency.

It is necessary to differentiate smallpox lesions from abscesses caused by bites of mosquitoes and mosquitoes that contain caseous masses. Smallpox occurring without complications causes a fibrotic reaction without a clearly defined necrotic focus.

Histological specimen of the spleen of a canary that died from smallpox. A small amount of mononuclear lymphocytes with intracytoplasmic inclusion bodies of the smallpox virus. Some inclusions have large vacuoles (marked by arrows). Photo from article
In corvid birds, the eyelids, skin around the eyes, and skin of the paws are often affected. On this photo hoodie (Corvus cornix) sick with smallpox.

In buntings, histological examination of pockmarks and other associated lesions reveals not only typical intracytoplasmic Bolinger bodies, but also intranuclear inclusion bodies. In canaries affected by smallpox, inclusion bodies similar to a retrovirus are found in the brain tissue. An adenoma may develop in the lungs of birds affected by smallpox.

Smallpox in a jackdaw ( Corvus monedula).
Smallpox in the common magpie ( Pica pica). Paw damage.

In serological studies of different strains of the virus isolated from passerine birds, no cross-reaction has been observed, but some strains of smallpox can infect several species of passerine birds. In one documented case of a smallpox outbreak in an outdoor aviary containing more than 10 different passerine birds, clinical signs of disease and high mortality were observed only among canaries and house sparrows.

Treatment, prevention and control:

There is no specific treatment for smallpox. To prevent the development of secondary bacterial infections, broad-spectrum antibiotics are used. To speed up the recovery of sick birds, vitamin A preparations are used and/or the birds’ diet is enriched with feed containing a large amount of carotenoids. Removal of pockmarks may lead to spontaneous recovery. Topical application of solutions of tannins, such as solutions of organomercury preparations (merbromine) and alcohol solutions, can be clinically effective in treating birds from the cutaneous form of pox. The use of ointments based on adenine arabinoside is also recommended. To remove pock marks on the skin around the eyes, soaking the scars with non-irritating baby shampoos effectively helps. Immunostimulants and echinacea preparations can have a positive effect in treating birds against smallpox.

In the event of an epidemic, all birds should be placed in individual cages or the flock of birds should be divided into small groups. All birds without signs of infection should be vaccinated and provided with a rich diet with additional multivitamin supplements. Antibiotics are used to prevent or treat secondary bacterial diseases. If there is no mortality and new clinically sick birds are identified within 2 weeks, quarantine can be ended and the birds can be returned to their cages or enclosures.

Vaccination:

To vaccinate canaries and other songbirds against smallpox, a vaccine made from a lyophilized modified canarypox virus, Poximune C, is used. In the CIS countries, this vaccine is not certified and cannot be officially purchased. Preventive intradermal vaccination in the area of ​​the wing fold is carried out in early summer and repeated once a year.

Several species of passerine birds were successfully vaccinated with this vaccine, including experiments with the eradication of introduced canary pox on some islands. The results have not been fully studied, but in isolated populations wild birds Thus, it was possible to significantly reduce deaths.

It was not possible to find any material on the use of fowlpox vaccine for songbirds, but given the genetic relatedness of the pathogens, one can assume a potential protective effect from the use of vaccines developed for chickenpox.

The fowlpox virus can be transmitted by mosquitoes, mosquitoes, ticks or by contact from sick birds to healthy ones, through equipment and drinking water. Aviation and bird rooms should be equipped with mosquito nets; In the event of a disease outbreak, the premises are treated with insecticidal preparations. Sick and suspicious birds should be placed in a quarantine facility. Birds that have recovered from the disease receive non-sterile immunity to the disease and can remain carriers of the virus.

Disinfection:

Sodium hypochloride is an effective disinfectant that kills the smallpox virus in the environment and on equipment. Disinfection of cages and equipment is an important measure to help stop the spread of the virus in the bird collection.

Herpesvirus

Herpesvirus causes conjunctivitis and respiratory problems in Australian and African finches and toucans. Gould's finches are very susceptible and can easily become infected from recently imported wild finches from Africa.

Herpesvirus was isolated from Astrildidae, weavers (weavers and widowweeds ( Viduidae)) and canaries, but in most cases, outbreaks of infectious herpesvirus conjunctivitis have been reported among captive Gouldian finches.

A herpes virus was isolated from a deceased toucan, which had shown decreased activity and loss of appetite several days before its death. Histological examination revealed total hepatitis and intranuclear inclusion bodies in hepatocytes and spleen cells.

The diagnosis is confirmed by the detection in cytological and histological preparations of basophilic intranuclear inclusion bodies in the epithelial cells of the trachea and conjunctiva.

There is currently no specific treatment for songbird herpes. There are also no vaccines. If a herpes virus infection is suspected, the flock should be divided into small groups, the premises should be disinfected, and the food varied as much as possible. All newly arrived birds should be quarantined.

Cytomegalovirus

An epidemic of conjunctivitis with concomitant damage to the respiratory system and a 70% mortality rate has been documented among sharp-tailed finches (Poephila acuticauda) kept in captivity. Histological analysis of the epithelium of the conjunctiva, esophagus and trachea reveals intranuclear basophilic inclusion bodies in the giant nuclear cells of the epithelium. By electron microscopy, these inclusion bodies were classified as cytomegalovirus particles.

Polyomavirus

Polyomavirus is found in finches in Australia, Europe and the United States, and the disease may be more common than it is diagnosed. Most often these infections are recorded in Astrildov (Estrildidae), y finches (Fringillidae)(Gouldian finches, painted astrilds, canaries, goldfinches) and White-rumped Shama Blackbirds (Copsychus malabaricus). Infections caused by viruses similar to polyomavirus have been reported in several species of passerines, including American Siskins (Spinus tristis), sharp-tailed finches (Poephila acuticauda), common greenfinches (Chloris chloris). Sudden death of adult finches different types noted in birds after transportation and other stress factors. At autopsy of these birds, gastric mycosis was also noted, which occurred against the background of polyomavirus infection.

The disease leads to increased mortality among chicks, developmental delays in chicks, beak deformation and sudden death. Often these viral infections are complicated by secondary bacterial diseases. Pathoanatomical features include spleno- and hepatomegaly and/or adenomatous lung lesions. Histological lesions: necrosis of hepatocytes, myocarditis or pulmonary adenoma, in which karyomegaly with foamy intranuclear inclusions is detected. The diagnosis is made on the basis of a positive reaction with fluorescent antibodies in fingerprint smears of the liver and spleen. Electron microscopy of intranuclear inclusions reveals discrete round or icosahedral (20-sided) electron-dense particles 45–50 nm in size.

In Gouldian finches with color mutations, a polyomavirus-like infection has been documented, causing sudden death of 2-3-day-old chicks, developmental delays, poor feather quality, and delayed juvenile molt in fledglings. Many sick finches had a developmental disorder of the mandible, which became much larger than the mandible and had a tubular shape. At the same time, non-specific signs of bird diseases and an increase in mortality in adult birds were noted. The development of candidiasis was often observed.

photo polyomavirus infection in Gouldian finches.

Signs of polyomavirus in Gouldian finches: baldness, beak deformation, constant molting, the head is covered with a large number of small feathers that do not open.

In one study, increased mortality in adult chicks and fledglings of Gould's finches was observed without associated plumage and beak lesions. The most common sign of infection at autopsy was an enlarged, discolored liver.

There is currently no effective treatment for polyomavirus. There is no consensus on the control and prevention of the disease, which is best strategy— complete depopulation of the collection or continued breeding in the hope that the birds in the flock will develop immunity.

Although intranuclear inclusion bodies similar to polyomavirus have been described in many cases of finches in North America, Europe and Australia - the virus has not been isolated in pure form from passerine birds.

Pathological changes in passerine birds with polyomavirus infection are as follows: perirenal hemorrhages, splenomegaly, hepatomegaly and liver discoloration. Histologically, amphophilic intranuclear inclusion bodies are found, most often in cells of the kidneys, heart, spleen, gastrointestinal tract or hepatocytes.

The diagnosis is made based on the histological detection of large transparent or amphophilic intranuclear inclusions in the cells of one or more organs. When fluorescent polyclonal antibodies specific to polyomavirus antigens are used, fluorescence is observed. Electron microscopy reveals polyomavirus particles.

Papillomavirus

Avian papillomavirus was isolated from papillomas on the feet of wild finches; the infection leads to the formation of slow-growing, dry, wart-like epithelial growths on the skin of the paws. In one study, 230 finches out of 25,000 examined were affected by papillomas. The virus was isolated in its pure form, which helped determine its physicochemical properties.

Photo of a finch with papillomavirus lesions on its paws.

Viral papillomatosis has been described in canaries in Argentina. The disease was highly seasonal, occurring in late summer and autumn over a three-year period. The epidemic was controlled by hygienic measures and with the help of an autogenous vaccine.

Treatment of papillomatosis in passerine birds, as well as in parrots, often involves removing papillomas using radiosurgery, cryosurgery, and laser. It is necessary to carry out a set of measures aimed at increasing the immune status of poultry and improving hygienic living conditions. Commercially available vaccines against papilomatosis of passerine birds on this moment No.

Papillomas on the paws of a finch ( Fringilla coelebs) These lesions on the feet of birds are similar to knemidocoptic mange, but only similar. Upon careful examination, the different nature of the lesions on the skin of the paws caused by these pathogens is obvious.
Photo of a tit's paws, presumably affected by papillomatosis.

Paramyxovirus

In passerine birds, three types of paramyxcoviruses have been noted: groups 1, 2 and 3.

Group 1. (New Castle disease). Many weaver species are susceptible. When these birds become ill, conjunctivitis, pseudomembranous tracheitis, laryngitis and sudden death of the birds are noted. Neurological signs of the disease are rare. Canaries infected with New Castle disease rarely show any clinical signs of the disease; such birds are often asymptomatic carriers. Because susceptibility to the virus varies greatly among bird species, mortality in mixed collections of passerines also varies greatly, making diagnosis difficult. In mynahs, New Castle disease (PMV-1) has been described in recently imported birds; clinical signs in these birds included neurological disorders (opisthotonus) and bright green, misshapen droppings. Clinical signs of disease developed 4 weeks after the birds were added to the collection.

Group 2. The carriers of the virus are wild passerines, especially weaver birds ( Ploceus spp..) in North America. Many infected birds do not have any clinical signs of the disease; some cases develop pneumonia, exhaustion and death.

Group 3. This type of virus has been isolated from a large number of different passerines, including Gould's finches, zebra finches, Malabar finches ( Lonchura malabarica cantans) and weavers. In these birds, serotype 3 of the virus causes the development of neurological signs characteristic of “whirling” - the classic “curvature of the neck”, i.e. Torticolis, trembling, paralysis. Associated symptoms include lethargy and exhaustion. Infected birds may remain carriers for months before clinical signs of the disease appear.

A large number of cases of paramyxovirus infection types 1, 2 and 3 have been documented in mynahs and toucans.

The primary diagnosis is made based on clinical signs. The final diagnosis is confirmed by serological tests and virus isolation. Pathological signs are nonspecific. Histologically, in some cases, confluent pancreatitis is detected.

There is no specific treatment for New Castle disease in birds. The use of antibiotics does not significantly increase the number of surviving birds.

Differential diagnosis is made from a lack of vitamin E associated with rancidity of fat-containing components of the grain mixture or the addition of rancid vegetable oils to the grain mixture.

An inactivated vaccine is used to prevent the development of infection.

Picornavirus (Avian Keratin Disorder)

A new viral disease of corvids and tits that was reported in Alaska in the mid-2010s; At first, researchers could not isolate the causative agent of the infection, so the cause of the disease remained unknown for a long time. In Alaska, there has been a sharp increase in the number of tits, northwestern crows ( Corvus caurinus), Canadian nuthatches ( Sitta canadensis) with abnormally long beaks, the birds died from exhaustion because the shape of the beak does not allow them to normally obtain food and care for their plumage. The disease is called Avian Keratin Disorder (avian keratin development disorder - AKD). In 2006-2008 in Alaska, the number of crows with deformed beaks reached 17% of the total crow population and 6% of the black-capped chickadee population ( Poecile atricapillus). It was only in 2016 that a virus from the picornavirus family was identified ( Picornaviridae) -the new virus was named poecivirus.

Deformation of the mandible and mandible in black-capped chickadees affected by AKD (Avian Keratin Disorder). On the left for comparison is a photo of a normal tit beak. Photo from the article Novel Picornavirus Associated with Avian Keratin Disorder in Alaskan Birds.
Black-capped chickadees and northwestern crows have AKD.

West Nile Virus

West Nile virus (also West Nile encephalitis, West Nile encephalitis, West Nile fever, West Nile fever; lat. Encephalitis Nili occidentalis) is an acute, incompletely studied viral disease transmitted by mosquitoes of the genus Culex (Culex pipiens) and characterized by fever, inflammation of the meninges, systemic damage to the mucous membranes and lymphadenopathy. It is distributed mainly in tropical and subtropical regions, but after the start of mass tourism by Russians to these regions, it is increasingly being recorded in Russia, especially in the south, where the virus is more viable. Birds are primarily susceptible to the virus, but also people and many mammals (horses, cats, the bats, dogs, chipmunks, skunks, squirrels, rabbits, etc.), which become infected after being bitten by an infected mosquito.

The video shows a carrion crow with clinical signs consistent with West Nile fever. Corvids are extremely susceptible to this virus, which causes encephalitis in affected birds.

There is no specific treatment for West Nile fever in birds. proper care birds may recover; however, given the potential zoonotic hazard, treatment of infected birds is not recommended.

Reovirus in corvids

Other viral infections

Avian influenza infections have been reported in finches and in recently imported mynas.

In canaries, an epidemic with high mortality of chicks and fledglings caused by an adenovirus has been documented, and neurological symptoms have been observed in affected birds.

Also, a coronavirus was isolated from canaries with breathing disorders (breathing with an open beak) from the trachea.

A circovirus was discovered in canary chicks with black spot syndrome (enlarged gallbladder).

Leukemia

In canaries in Europe, Australia, and North America, leukemia is observed, which occurs with damage to the liver and spleen. The diagnosis is confirmed histologically. The viral etiology of the disease is discussed, but has not yet been confirmed. The use of prednisolone may reduce the rate of development of leukemia.

Kozlitin V.E.

References:

1. Avian medicine: principles and applications. Ritchie, Harrison and Harrison. © 1994. Wingers Publishing, Inc., Lake Worth, Florida
2. Handbook of avian medicine. Second edition. edited by T.N. Tully. Jr., G.M. Dorrestein. A.K. Jones. © 2000 Saunders elsevier.
3. Avian Medicine and Surgery in Practice Companion and Aviary Birds. BOB DONELEY. Second edition. 2016 by Taylor & Francis Group, LLC
4. Novel Picornavirus Associated with Avian Keratin Disorder in Alaskan Birds. Maxine Zylberberg, Caroline Van Hemert, John P. Dumbacher, Colleen M. Handel, Tarik Tihan, Joseph L. DeRisia,
   Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, California, USA; California Academy of Sciences, San Francisco, California, USA; U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, USA; Department of Pathology, University of California, San Francisco, San Francisco, California, USA; Howard Hughes Medical Institute, Chevy Chase, Maryland, USA

In contact with

The most dangerous diseases of chickens are caused by various aggressive microorganisms - bacteria, viruses and fungi.

Infections are characterized by the following general symptoms:

• sudden onset of symptoms;
• mass distribution;
• severe course, high mortality;
• presence of characteristic symptoms.

Viral diseases

Viral diseases are remarkable in that they have no cure. The only way to combat them is to slaughter all sick birds and vaccinate healthy ones.

Newcastle disease (pseudoplague of birds)

A very dangerous disease. In our country, outbreaks often occur both in poultry farms and in private backyards. Ducks, geese, sparrows, pigeons, and pheasants are susceptible. A person can also become infected with this virus, but the illness passes easily, within 3-4 days with symptoms of a runny nose, and sometimes mild conjunctivitis can develop.

In case of an outbreak of the disease in unvaccinated livestock, the death of the bird occurs within 2-3 days, the mortality rate reaches 70-100%.

Symptoms of Newcastle disease. In vaccinated livestock, the disease can progress differently. Mainly there are signs of damage to the nervous and respiratory systems: paralysis of the wings, neck, and tail of chickens. In unvaccinated flocks, birds develop a cough, runny nose, purulent discharge from the eyes and nose, diarrhea and hemorrhages in the internal organs. Sometimes there is a sudden mass death without any external symptoms.

Control measures. Sick birds are destroyed using a bloodless method, healthy birds are vaccinated with live vaccines.

Vaccine from Strain "N" (dry) produced by the Federal State Unitary Enterprise "Stavropol Biofactory".

Bird flu

Another name for the disease is bird plague. The virus that causes the disease is extremely diverse and constantly changing. Most types of this virus are not dangerous to humans; some can cause mild illness with cold-like symptoms. The exception is the notorious H5N1 type, which appeared in Russia in mid-summer 2005. Cases of human avian influenza in the territory Russian Federation not registered.

Symptoms of bird flu. The plague is characterized by a rapid course of the disease, the sudden death of a large number of chickens (up to 70-100% within a few days). General depression, swelling of the head and neck, cyanosis of the earrings and comb, mucous membranes are also noted, a coma develops, followed by death.

Control measures. All sick birds and those in contact with them are destroyed in a bloodless manner.

Infectious bursal disease (Gumboro)

This chicken disease is usually brought in from chickens purchased from unsafe factories. Young chickens aged 2-20 weeks are susceptible to it. The virus attacks the immune system.

Symptoms Signs of Gumboro disease are uncharacteristic: yellowish-white diarrhea, ruffled plumage, decreased or absent appetite, depression. Symptoms such as trembling of the muscles of the neck, head, torso, and also cannot be excluded. The disease can occur without any symptoms. The virus greatly reduces poultry resistance to other infectious diseases.

Control measures. Sick chickens are killed and after boiling the carcasses can be eaten. Gumboro virus can persist in droppings for a long time. The feasibility of vaccinating healthy chickens is determined by a veterinarian. Sometimes all that is required is disinfection of the poultry house.

Inactivated vaccine Hipraviar-TRT4. Available in various dosages, in the photo there is a jar for 500 doses.

Infectious bronchitis of chickens

All ages of chickens are susceptible, but chickens up to 30 days old are more often affected. Laying hens that have had bronchitis reduce egg production by 50-60% and have shell defects. The mortality rate for IBD ranges from 10 to 35%; in chronic cases there are also large losses from loss of weight gain and eggs.

Symptoms In young animals, the virus affects the respiratory system, and in laying hens – the reproductive organs. Chickens with infectious bronchitis experience lethargy, drowsiness, loss of appetite, runny nose, inflammation of the eyes, and discharge from the nose and eyes. Inhalation is difficult due to the accumulation of mucus in the respiratory tract, the beak is open, and with each breath the chicken stretches its neck forward and upward. You may hear dry or wet wheezing, which can be heard from a distance as a squeak, squeak, or faint “kitten meow.” Dry wheezing can be detected at close range; if you bring such a chicken to your ear, you get the impression that there is an accordion inside it.

Control measures. In acute cases, treatment is not advisable. For chronic bronchitis, chickens are given broad-spectrum antibiotics, and aerosol treatments are carried out in the presence of the bird with antiseptic agents: iodine triethylene glycol, iodine monochloride, Monclavit, ASD-2, Ecocid.

The range of veterinary antiseptic "Monclavit-1" is varied and includes volumes from 350 ml to 20 liters.

Pneumoviral rhinotracheitis (chicken big head syndrome)

This disease affects the upper respiratory tract: the nasal cavity, larynx, trachea, and the mucous membrane of the eyes. The main symptom is swelling of the head, eyelids, and discharge from the eyes. In most cases, the chickens recover, but are severely stunted.

Treatment the same as for bronchitis in chickens.

Marek's disease

The virus mainly affects chickens, but other species from the order Gallini are also susceptible. Chicks become infected in the first days after hatching; subsequently, susceptibility decreases.

Symptoms Marek's disease takes a very long time to develop. The first signs appear between 70 and 120 days of age. Paralysis of the limbs, wings, tail, and neck is typical, depending on which nerve was attacked by the virus. In adult chickens - tumors in internal organs, enlargement of the liver and spleen several times. A characteristic feature for laying hens is a change in the shape of the pupil (iridocyclitis).

Control measures. Sick chickens are killed. Meat can be used for food if there is no sign of degeneration. Internal organs are disposed of. To prevent the disease, vaccination is necessary at one day of age. It can only be done at a clinic, since the vaccine requires special storage and use conditions.

Dry vaccine against Marek's disease "Avivak-Marek-3" with diluent. (all photos below can be enlarged by clicking)

Infectious laryngotracheitis

All ages of chickens are susceptible to the disease, but usually ILT manifests itself from 20-30 days to 8-9 months of age. The disease often appears when vaccinated stock is introduced into an unvaccinated herd.

Symptoms The disease affects the larynx, trachea and bronchi. Difficulty breathing, discharge from the eyes and nose, frequent coughing, wheezing and signs of suffocation. The bird dies due to mucus and inflammatory products that form a plug in the trachea. The formation of a bloody clot in the trachea is characteristic.

Control measures. Chickens exposed to the disease are destroyed, healthy ones are vaccinated. Treatment measures are carried out as for bronchitis of chickens.

Avivak-ILT - dry vaccine against infectious laryngotracheitis produced by Research and Production Enterprise "Avivak"

Bird pox

The disease is contagious to many species of birds - more than 60, including chickens, turkeys, guinea fowl, pigeons and sparrows. Birds between 4 and 12 months of age are most susceptible. Mortality ranges from 5-8% of the population for the cutaneous form and up to 50-70% for the diphtheric form.

Symptoms In the cutaneous form of bird pox, nodules - pockmarks - form on the comb, earrings, around the beak and cloaca, and on other non-feathered areas of the body. The pockmarks increase in size and merge to form a smallpox scab. With diphtheria, the virus affects the respiratory tract: nasopharynx, larynx, trachea.

Control measures. A sick bird is killed or treated (depending on the severity of the disease), a healthy bird is vaccinated. The pockmarks are lubricated with oils, glycerin, and ointments to soften the crust, then cauterized with tincture of iodine or a solution of potassium permanganate. Antibiotics are given to prevent bacterial infections.

In the photo - dry vaccine "Avivak-Ospa" and diluent (7.5 cm3).

Bacterial diseases

Bacterial infections can be no less dangerous than viral ones. But most of them can be successfully treated with antibiotics and other medicines. In addition, for some diseases there are specific sera containing antibodies to infectious agents.

Salmonellosis

Salmonellosis paratyphoid fever is caused by the bacterium Salmonella.

Symptoms The disease is accompanied by depression, drowsiness, muscle weakness, loss of appetite, lacrimation, nasal discharge, difficulty breathing, and diarrhea. Sometimes there is inflammation of the joints: they are swollen and hot to the touch.

Humans can become infected with this disease and can also serve as a source of infection for chickens. When eating meat or eggs with salmonella, a person develops a toxic infection.

Treatment of salmonellosis. Drinking or injection of antibiotics: enrofloxacin, neomycin, tetracycline, gentamicin. The introduction of anti-salmonella medicinal serum is effective. It is also recommended to inject young animals upon entering the farm to prevent the disease. Attention! Meat and products from chickens with salmonellosis should not be eaten.

"OKZ vaccine" produced by Moscow LLC "Agrovet" against salmonellosis and colibacillosis.

Pullorosis-typhoid

The disease is caused by a special type of salmonella that affects only birds. Chickens 5-20 days old are most susceptible. The mortality rate can reach 70%. In laying hens, the disease is transmitted through eggs, causing a 50% reduction in hatchability.

Symptoms White or green mucous diarrhea is characteristic. Appetite decreases, chickens die after 1-2 days.

Treatment for pullorosis typhus is the same as for salmonellosis.

Colibacillosis

The disease is caused by Escherichia coli. The disease manifests itself as drowsiness, depression, loss of appetite, thirst, diarrhea, growth retardation, and sometimes inflammation of the joints and subcutaneous tissue (after 20 days of age).

Control measures. Improve feeding and sanitation conditions. The birds are given antibiotics: enrofloxacin, oxytetracycline, doxytetracycline. Furazolidone is added to the feed at the rate of 4 g per 1 kg of mixture.

Enrofloxacin is a 10% veterinary solution for injection for feeding to animals against colibacillosis.

Diseases caused by fungi

Aspergillosis

Aspergillosis is caused by a microscopic mold called Aspergillus. Infection occurs when eating moldy food or being kept in unsanitary conditions. The respiratory tract is mainly affected, and nodules form in the internal organs.

Symptoms The bird is lethargic, inactive, breathing is rapid and labored. Sick birds stretch their heads and necks, open their beaks, trying to swallow air. Sneezing and coughing, inflammation of the eyes are possible; towards the end of the illness, exhaustion and sometimes diarrhea develop. The bird dies with symptoms of paralysis after a few days, sometimes weeks.

Treatment. Inhalation of iodine preparations, nystatin, revolin. Nystatin is given orally at the rate of 15-20 mg for adult chickens and 2-5 mg for chickens, potassium iodide 0.15-0.30 mg per head. Instead of drinking water, give a solution of copper sulfate at a dilution of 1:2000 for 4-5 days.

Nystatin tablet against aspergillosis must first be turned into powder and mixed with water. The medicine does not dissolve well.

Infectious diseases of chickens and other poultry are always easier to prevent than to treat. Therefore, if there is an infection on your farm, you need to take a number of measures: eliminate the source of infection, improve the health of the herd by culling sick animals; disinfect the poultry house and decide on the advisability of vaccination. Remember that a diagnosis of a contagious disease must be made by a veterinarian after examination of the livestock, post-mortem examination of the bird and, if necessary, laboratory tests.

Viral diseasesbirds.

HOW TO RECOGNIZE BIRD POX?

Bird pox is a viral disease of chickens, turkeys and many other species of birds, characterized by lesions of the featherless part of the skin and/or diphtheria lesions of the mucous membranes of the oral cavity and respiratory tract. Bird pox can occur in cutaneous or diphtheria form or both. Cutaneous form The disease is characterized by nodular lesions on the crest, catkins, eyelids and other non-feathered areas of the body. At diphtheria form Ulcers or diphtheritic yellowish lesions form on the mucous membrane of the mouth, esophagus or trachea, accompanied by mild to severe respiratory symptoms.

In most cases, outbreaks occur in the cutaneous form. Lesions may vary depending on the stage of development: papules, vesicles, pustules or crusts. Lesions are usually located in the head area.

Defeats all around anus at the pigeon.

Often, the conjunctival mucosa affected by the smallpox virus is an entry point for other pathogenic agents. (E. Coli, bacteria of the genus staphylococci. etc.) and the development of complications. The infection spreads mechanically through the peeling of skin crusts that contain it. Some mosquitoes and blood-sucking arthropods can also spread the smallpox virus. Mosquitoes retain their infectious properties for several weeks. The incubation period ranges from 4 to 10 days. The disease spreads slowly and many weeks can pass between its onset and severe outbreaks.

Diphtheria lesions appear as whitish or yellowish plaques on the mucous membranes of the oral and nasal cavities, sinuses, larynx, pharynx, trachea, or esophagus (arrows). Diagnosis is made on the basis of typical skin and diphtheria lesions. Birdpox is prevented by vaccination, which can be done at any age if necessary.

NEWCASTLE DISEASE - CONTROL AND PREVENTION

PREVENTION AND CONTROL. Regardless of the level of control (international, national or farm level), the aim is either to prevent infection of susceptible birds or to reduce the number of susceptible birds through vaccination. When guiding the first strategy, it is necessary to consider all methods of spreading the disease to prevent it.

Prevention of ARVI 3 doses against flu and colds. Protect yourself and your family with Vicks Active! vicks.ru There are contraindications. Consult your doctor.

Control strategy at the international level. Currently, the expansion of industrial poultry farming and trade in its products are organized on an international basis. This is often done under the control of multinational companies. In addition, there is a tendency to trade both poultry products , and genetic reserve. However, a strong deterrent to such trade is the threat Newcastle disease . Global control of Newcastle disease will only be achieved if all countries report outbreaks within their borders to international authorities. The adoption of international agreements on this and other issues is not easy, given the vast differences in disease control measures between countries.

A prerequisite for the formation of control policies, especially international ones, must be agreement on the procedure for identifying the disease and policies regarding virus control. Some countries do not use vaccination and do not want to Newcastle disease virus was brought into their packs in any form. Other countries only allow certain live vaccines, and some of the vaccines are considered unacceptably virulent. In addition, in some countries highly virulent viruses are constantly circulating, which, due to vaccination, do not appear as an obvious disease. Benjain suggested that any infection caused by a virus with a virulence index greater than 0.7 should be reported as Newcastle disease outbreak . This would be acceptable for those countries where only vaccines based on lentogenic and inactivated viruses are used. But absolutely not suitable for countries using vaccines based on mesogenic viruses or where enzootic mesogenic viruses exist. However, this definition is accepted by countries European Union for use as a control measure.

National control strategy. At the national level, control policies aim to prevent the introduction of the virus and prevent its spread within the country. To prevent the introduction of the virus Newcastle disease , most countries place restrictions on trade in poultry products, eggs and live poultry. But these restrictions vary widely.

Because of the association of caged exotic birds with the spread of Newcastle disease during the 1970–1974 panzootic disease and the known ability of parrot birds to shed ND virus for many weeks after infection, most importing countries have imposed quarantine measures on imported birds.

The 1980 Newcastle disease panzootic disease (PMV-1) among racing pigeons created a unique situation in terms of the potential for disease spread to poultry. Every year a large number of international competitions in high-speed flight among pigeons are held. Because of this, some countries have taken measures including banning such competitions, introducing restrictions into these competitions, or forcing the vaccination of participating pigeons.

Many countries have laws to control possible outbreaks Newcastle disease. Some countries have pursued eradication policies that involve the forced killing of infected birds, those that have come into contact with them, and their products. Such policies typically involve imposing restrictions on the movement or trade of birds within designated quarantine zones around areas with disease outbreaks. Others require prophylactic vaccination of birds even in the absence of disease outbreaks, and still others implement a policy of “ring vaccination” around areas with disease outbreaks to create a buffer zone.

Disease control and prevention measures at the farm level. Perhaps the most important elements preventing the introduction of the Newcastle disease virus and its spread during disease outbreaks are the conditions for keeping birds and the degree of biosecurity used on the farm.

Control measures for avian pneumoviruses. Turkey rhinotracheitis significantly aggravated by improper husbandry, namely improper ventilation, overcrowding, poor bedding, poor hygiene and mixing of birds different ages. Removal of the beak or vaccination with live viruses NB if these procedures are carried out at a critical moment. Endrel and his colleagues pointed out the difficulty of eliminating turkey rhinotracheitis in places where birds of different ages are kept and where it is impossible to carry out complete cleaning and disinfection.

Attempts to treat turkey rhinotracheitis and swollen head syndrome with antibiotics have had varying success.

Vaccination against Newcastle disease.

Ideally, vaccination against ND should lead to the development of immunity against infection and viral replication. In reality, vaccination against ND usually protects birds from more severe consequences of the disease, but replication and spread may continue, albeit at a lower level.

It must be borne in mind that under no circumstances should vaccination be an alternative to good housekeeping, biosecurity or adequate hygiene measures in poultry housing.

HISTORICAL ASPECTS OF VACCINATION. Early studies showed that inactivated infectious materials provided protection to inoculated chickens. However, problems with vaccine production and standardization prevented their widespread use. Research on the attenuation (weakening) of virulent strains of Newcastle disease virus carried out in the 1930s by Yer and Dobson led to the creation of mesogenic vaccine strains, which are still used in some countries.

Inactivated vaccines, which mainly use viruses adsorbed on aluminum hydroxide, were most often used in Europe until the panzootic period of 1970-1974. However, due to low effectiveness, live strain-based vaccines have been replaced in most countries. B1 and La Sota . This panzootic also gave impetus to the creation of modern inactivated vaccines based on oil emulsions, which have shown to be highly effective.

PRACTICE OF VACCINATION. Some countries have issued laws regarding the use and quality control of vaccines. The attitude towards this largely depends on the presence of panzootic awareness of the threat of Newcastle disease. Some countries such as Denmark, prohibit the use of any vaccines, while others, e.g. Netherlands, carry out compulsory vaccination of all poultry. In countries European Union laws have been issued regarding the determination of the pathogenicity of viruses. Based on the results of the inspections, permission will be given for their use as vaccines by the Union member states. The reference seed of live vaccines must be validated, have a strictly defined dose and have an intracerebral virulence index value below 0.4. At the same time, the reference seed material of inactivated vaccine viruses should have a value of this index below 0.7.

LIVE VACCINES

Virus strains. It is convenient to divide live vaccines against NDV into two groups: lentogenic and mesogenic . Mesogenic vaccines are suitable only for secondary vaccination of birds, as they are highly virulent. However, even within the lentogenic group there are significant variations in virulence. The immune response increases when the pathogenicity of live vaccines increases. Therefore, to obtain the required level of protection without adverse reactions, it is necessary to include in the vaccination program the sequential use of increasingly virulent viruses or the use of live viruses after inactivated vaccines.

Use of live vaccines . The purpose of using live vaccines is to cause infection to develop among birds, preferably throughout the entire flock. Individual application vaccines, such as intranasal administration, eye drops, beak dipping, are most often used for lentogenic vaccines . Mesogenic vaccines usually require inoculation by wing membrane puncture or intramuscular injection.

The main advantage of live vaccines is the possibility of application without the use of expensive techniques. Most often, live vaccines are used in drinking water. To do this, the birds are not allowed to drink for several hours. The vaccine is then added to fresh drinking water to a precisely calculated concentration to ensure that each bird receives a sufficient dose. In addition, adding the vaccine to a reservoir to supply water by gravity has been successfully used. The use of drinking water must be carefully controlled, since viruses can be inactivated by excessive heating of the water, its contamination, and even depending on the type of pipeline or vessels used for its distribution. To some extent, the viability of the virus can be increased by adding dry cream to drinking water.

The use of live vaccines by spraying and aerosols has become very popular. This is due to the ease of vaccination of a large number of birds within a short time. It is important in this application to achieve the correct particle size. To do this, it is necessary to control the conditions for aerosol production. Aerosols are usually used only for secondary vaccinations to avoid severe reactions to the vaccine. Spraying a coarse mist of water causes less reaction. This is due to the fact that large particles do not penetrate deep into the respiratory tract of birds. Therefore, this application is more suitable for mass vaccination of young birds. Spraying one-day-old chicks with large drops can lead to the development of infection caused by vaccine viruses in the flock, despite the immunity that young birds receive from their mother.

Advantages and disadvantages of live viral vaccines . Live vaccines are usually sold as lyophilized allantoic fluid from infected fertilized eggs. They are relatively cheap and easy to use, and are suitable for mass use. Infections caused by live viruses stimulate local immunity and, when used, protection is created very quickly. Vaccine viruses can spread between birds, resulting in successful vaccination of all birds.

But live viral vaccines also have a number of disadvantages. . The main one is the ability to cause the development of the disease under certain external conditions and the presence of complicating infections. Therefore, it is very important to use very weak viruses during the first vaccination, which requires repeated use of the vaccine. Immunity acquired from the mother may nullify the first vaccination with a live virus. Although the ability of vaccine viruses to spread within a flock may be an advantage, it can lead to severe disease in susceptible birds, especially in the case of dual infections resulting from disease-exacerbating microorganisms. Live vaccines can be easily inactivated by chemicals and heat, but if not properly controlled during production, they can become contaminated with other viruses.

INACTIVATED VACCINES

Production methods. Inactivated vaccines are usually made from infectious allantoic fluid treated with (3-propiolactone or formalin to inactivate the virus and mixed with a virus carrier adjuvant. Previously, aluminum hydroxide adjuvants were used for inactivated vaccines, but then oil emulsion-based vaccines were created. Such vaccines vary in the composition of the emulsion base, antigens and the ratio of water and oil.Currently, mineral oils are mainly used.

To produce oil-emulsion-based vaccines, Ulster 2C, B1, La Sota, Roakin and several other virulent viruses are used. The criterion for choosing a vaccine is the amount of antigen produced when the virus grows in fertilized eggs. Several other antigens may be included in the Newcastle disease virus emulsion; bivalent and polyvalent vaccines may include infectious bronchitis, infectious bursitis, decreased egg production syndrome, and reoviruses.

Use of inactivated vaccines. Inactivated vaccines are used as intramuscular or intravenous injections.

Advantages and disadvantages of inactivated vaccines. Inactivated vaccines are much easier to store than live ones, but they are more expensive to produce and use due to the high labor costs. Labor costs can be partially offset by the use of polyvalent vaccines. Inactivated oil-emulsion vaccines are not affected by maternal immunity, which usually occurs with live vaccines. That is why they can be used to vaccinate one-day-old chicks. The main features of inactivated vaccines are very low level adverse reactions in vaccinated birds, the possibility of their use in situations where the use of live vaccines is unacceptable, especially in the presence of pathogenic microorganisms. Another advantage of inactivated vaccines is that they produce extremely high levels of protective antibodies that last a long time.

VACCINATION PROGRAMS. Vaccination programs and vaccines may be controlled by government agencies. Programs should be prepared taking into account the prevailing disease situation and other factors. Such factors include suitability of vaccines, maternal immunity, use of other vaccines, presence of other microorganisms, flock size, life expectancy of the flock, possible labor costs, climatic conditions, recent vaccination history and cost.

Timing of vaccination of broiler chickens can be particularly challenging due to the presence of maternal antibodies. Due to the short life expectancy of broilers, vaccination of such chickens is sometimes carried out in countries with a low risk of Newcastle disease.

Vaccination of laying hens requires more than one dose to maintain immunity for

life.

INTERPRETATION OF THE VACCINE RESPONSE. The immune response to Newcastle disease virus is usually assessed by hemagglutination inhibition titers (ITs). A single vaccination with a live pathogenic virus causes a reaction in susceptible chickens with titers ranging from 2.4 to 2.6. However, when implementing a vaccination program using oil-emulsion-based vaccines, TG titers can reach 2.11 or higher.

VACCINATION OF OTHER DOMESTIC BIRD. Vaccines are developed primarily to protect chickens. But they can be successfully used for other birds, although there may be some differences in the immune response. For example, turkeys have a weaker response and as a result they are often first vaccinated with the La Sota strain following the oil emulsion vaccine. However, there is evidence that La Sota virus can cause adverse reactions in the respiratory tract, and aerosol vaccination with lentogenic viruses causes pathological lesions in the trachea. Guinea fowl and partridges are successfully vaccinated using vaccines based on the La Sota virus and oil-emulsion vaccines. In connection with the panzootic epidemic of the 1980s, extensive research work was carried out among pigeons on the most suitable vaccines for them and the order of their use.

VACCINATION AGAINST BIRD PNEUMOVIRUSES. Both live attenuated and inactivated vaccines are currently available. Problems with reproducing the disease in the laboratory make the job of attenuating viruses very difficult. Live inactivated turkey rhinotracheitis virus vaccines are used for both turkeys and chickens. However, the results of field studies are not consistent. At present, it remains unclear whether this is due to antigenic changes noted in avian pneumoviruses, interference of concurrent infections (possibly immunosuppressive), or some other reasons.

Newcastle disease - how to recognize?

Newcastle disease virus Paramyxovirus (PMV-1) is a dangerous pathogen for poultry. Representatives of the family Paramyxoviridae belong to RNA-containing viruses with a nucleocapsid of helical symmetry. The genome is represented by a single single-stranded linear molecule minus (-) RNA. Viruses are covered with an envelope, which is formed from modified sections of the cell membrane when the virus budding from the cell surface after the formation of a capsid complex in the cytoplasm. The result of the Newcastle disease virus is a disease that varies greatly in appearance and severity. In this regard, nomenclature problems often arise. This usually happens when the disease is first detected in the country. As a result of this, Newcastle disease there are many other names: fowl pseudoplague, atypical fowl plague, fowl pseudoplague, fowl plague, Ranikhet disease, Tethelo disease, Korean fowl plague and avian pneumoencephalitis. A feature of Newcastle disease that complicates its treatment is that different isolates and strains of the virus cause diseases of very different severity, even in one carrier, for example, chickens. To solve nomenclature problems, Bird and Henson proposed the following division into forms of the disease, based on clinical symptoms in chickens.

1. Doyle's form. It is characterized by an acute course, high mortality, susceptibility to the disease in chickens of all ages, and the presence of hemorrhagic lesions of the digestive tract. This form of the disease is called velogenic viscerotropic Newcastle disease (VNDD).

2. Beach form. It is characterized by an acute course, often with fatal. In this form of the disease, affected birds typically exhibit respiratory and neurological symptoms. As a result, it is called velogenic neurotropic Newcastle disease (VNDND).

3. Bodette form. It is less pathogenic than velogenic neurotropic New Castle disease, and only young birds are susceptible to death from it. The viruses that cause this form of the disease are moderately virulent and can be used as a secondary live vaccine.

4. Hitchner form. It is represented by mild or asymptomatic respiratory infections caused by viruses of reduced virulence, which are usually used as live vaccines.

5. Asymptomatic intestinal form. It includes mainly intestinal infections caused by viruses with reduced virulence. In this form, the disease proceeds secretly.

Clinical diseases of chickens resulting from infection with avian pneumovirus are called swollen head syndrome (SOG), and in turkeys - turkey rhinotracheitis (RTI). The symptoms of these diseases are not limited to infections caused by avian pneumovirus. Therefore, they can be confused in turkeys with diseases caused by infection with microorganisms such as Bordetella avium. However, conditions related to turkey rhinotracheitis or swollen head syndrome may result from infection with the same pneumoviruses. More severe forms of comorbidity may occur from dual or secondary infections caused by other microorganisms.

Newcastle disease

is one of the most contagious diseases in many species of domestic, exotic and wild birds, characterized by marked differences in morbidity, mortality, symptoms and lesions. Clinical and morphological signs have obvious viscerotropic or neurotropic character. In the viscerotropic form, hemorrhagic diphtheria lesions of the entire digestive tract from the beak to the anus are observed. Hemorrhages of the epithelium of the muscular stomach are characteristic. The mucous membrane is edematous, covered with thick mucus and dotted with one to numerous hemorrhages, sometimes localized at the border between the muscular stomach and the esophagus.

Typical for this form are hemorrhagic necrosis and diphtheroid lesions of the mucous membrane of the goblet, stomach and intestines. The disease is usually common among chickens, less often in turkeys, exotic and wild birds. The disease affects birds at any age. Depending on their pathogenicity, the numerous known strains of paramyxovirus are classified as having reduced (lentogenic), medium (mesogenic) and high (velogenic) virulence. Vaccines based on strains with reduced virulence provoke short-term immunity, which requires revaccination. Vaccines based on mesogenic strains induce strong, long-term immunity, but can also cause death, especially in birds without primary immunity based on vaccine strains with reduced virulence.

Dilatation and hemorrhages in the cecum and hemorrhagic cloacitis can often be observed. Typically, these lesions begin in the lymphoid tissue of the mucosa. The infection can be transmitted either by inhaling contaminated air or by ingesting viruses and depends on the presence of infectious forms of the viruses. Of course, infectious viruses may be present in aerosols.

In this case, birds exposed to an atmosphere containing such aerosols become infected. This is the basis for the use of live vaccines, sprayed using atomizers or aerosol generators. During the natural spread of infections in nature, large and small droplets containing viruses are released from infected birds as a result of replication in the respiratory tract. Transmission of the virus can occur through dust and other particles, including feces. These particles containing the virus are inhaled by birds or land on mucous membranes and lead to infection. However, the ability of such aerosols to form or maintain infectious viruses long enough for transmission depends on many environmental factors. The source of infection is virus-containing excrement of infected birds, which contaminates feed, water and environment. The virus contained in the hatching eggs leads to the death of the embryo. An important factor Exotic birds and fighting cocks may carry the highly virulent virus. Mortality can reach 70−100%.

Neurotropic form of the disease clinically manifests itself as ataxia, opisthotonus, paresis and paralysis of the legs. This form is often accompanied by respiratory symptoms.

The lesions caused by paramyxovirus in pigeons are completely identical. Based on history and clinical and morphological signs, a preliminary diagnosis can be made, but laboratory confirmation is mandatory. BN should be distinguished from bird flu , bird cholera.

Reduced egg production syndrome (RES −76)

Since its initial description in 1976, reduced egg production syndrome (DEL-76) has become a major cause of decreased egg production worldwide. Group III adenovirus is responsible for the development of this syndrome. It probably gets to the chickens with the vaccine.

Reduced egg production syndrome SSY-76 characterized by the fact that healthy birds lay eggs with thin shells or no shells at all. Horizontal transmission of the virus occurs slowly when poultry are kept in cages, but much faster when kept on floors. The first sign is loss of egg pigmentation, quickly followed by soft and deformed shell. If defective eggs are discarded, the rest are fertilized and incubated without problems. The drop in egg production can be sudden or prolonged. Typically it lasts 4-10 weeks and egg production is reduced by about 40%. Apart from inactive ovaries and atrophy of the oviducts, no other damage was found. Replication of the virus in the epithelial cells of the oviduct leads to severe inflammatory and dystrophic changes in the mucous membrane. The appearance of eggs with poor quality and a decrease in egg production indicate the emergence of a virus on the farm SSY 76 . The diagnosis is confirmed by serological tests and is confirmed after isolation and identification of the virus. In many cases, specific antibodies are not detected in infected flocks until egg production approaches levels between 50% and peak production. If egg production syndrome virus appeared in farms engaged in bird breeding , this most often manifests itself in the inability to achieve target indicators production, while changes in egg shells are less obvious, although present. Since the syndrome was first described, it has become apparent that sporadic outbreaks SSYA-76 occur when birds become infected through direct or indirect contact with infected wild or domestic waterfowl.

This virus only affects birds and has no effect on public health.

How to recognize infectious bursal disease (Gambora)?

Infectious bursal disease (IBD, Gumboro) is an acute, highly contagious viral infection of chickens, manifested by inflammation and subsequent atrophy of the bursa of Fabricius, various degrees of nephroso-nephritis and immunosuppression. Clinically, the disease manifests itself only in chickens older than 3 weeks .

The feathers around the anus are usually matted and colored white due to the large amount of urates.

The period of highest mortality is between 3 and 6 weeks of age, but can occur up to 16 weeks. Before the age of 3 weeks, IBD can be subclinical, but leads to suppression of the immune system.

In addition, diarrhea, anorexia, depression, and ruffled feathers, especially in the head and neck area, may occur.

Natural infection with IBD is mainly observed in chickens. In turkeys and ducks it can be subclinical, without immunosuppression. In premises where IBD was recorded once, the disease tends to recur, usually in a subclinical form. The corpses are dehydrated, often with hemorrhages in the chest, thigh and abdominal muscles.

The IBD virus belongs to the Birnaviridae family of RNA viruses. There are two serotypes of the virus, but only serotype 1 is pathogenic. The virus is very resistant to most disinfectants. In contaminated areas it can persist for months, and in water, feed and feces for several weeks. The incubation period is short, and the first symptoms appear within 2-3 days after infection. The lesions primarily affect the bursa of Fabricius; at the beginning, the bursa enlarges and becomes swollen. The IBD virus has a lymphocidal effect and primarily affects the lymphatic follicles of the bursa.

IBD lesions go through various stages from isolated hemorrhages to severe hemorrhagic inflammation. The incidence is very high and can reach 100%, while the mortality rate is 20 - 30%. The disease progresses in 5-7 days and the peak mortality occurs in the middle of this period.

In some cases, the bursa becomes filled with coagulated fibrinous exudate, which usually takes the form of an impression of the shape of the folds of the mucous membrane. In birds that survive the acute stage of the disease, the bags gradually atrophy.

The kidneys suffer greatly from severe diathesis caused by urate deposition. The use of live vaccine in chickens is a key point in the prevention of IBD. All poultry are vaccinated at the age of 10 days.

Differential diagnosis and vaccination against Marek's disease

Virus isolation. Despite the fact that conventional methods of virus isolation are ineffective in making a diagnosis of BM, they are valuable in studying the epidemiological and other characteristics of the virus. Related methods are used to titrate VBM and related vaccine viruses. Marek's disease virus can be isolated after just one or two days after inoculation, or after 5 days after exposure and throughout the life of the chickens. Inoculation of intact viable cells is preferred since most infectivity is cell related. At the same time, the virus may contain cell-free preparations of skin, dandruff, or feather tips of infected chickens.

Marek's disease virus was isolated by direct culture of kidney cells from infected chickens. To prove the presence of the virus, the use of a rapid method using lymphocyte cultures after a fluorescent antibody reaction is especially useful. This method can also be used for virus isolation when cultured antigen-positive lymphocytes are transferred to sensitive monolayer cultures.