Infectious laryngotracheitis of birds. The main signs of damage. complete feeding with high quality food

As for young chickens, their laryngotracheitis can cause blindness, frolicking due to conjunctivitis.

Infectious tracheitis (ILT) is a viral disease that mainly affects chickens. The virus is localized in the mucous membranes of the larynx, trachea, less often the conjunctiva of the eyes and nasal cavity. The disease was first described in 1925 in the United States, but there is reason to believe that ILT has occurred before.

Currently, infectious laryngotracheitis of chickens occurs in many countries: England, Holland, France, Germany, Hungary, Poland, Yugoslavia, Canada, USA, Italy, Sweden, Spain, South Australia, New Zealand, Indonesia.

In Russia, outbreaks of the disease are periodically recorded in all regions, but mainly large poultry farms suffer from ILT.

Characteristics of the disease

Chickens, peacocks, pheasants and some ornamental birds are susceptible to the disease. ILT is more often manifested in young chickens aged from 60 to 100 days, in disadvantaged areas - from 20-30 days of age.

The virus can also infect humans. This happens to people who have been working with vaccine material for a long time or are forced to come into contact with highly aggressive strains (workers in biofactories and laboratories). With poultry products - meat, eggs, feathers - a person cannot become infected.

In chickens, the disease is transmitted from beak to beak. A sick bird develops strong immunity, but remains a lifelong carrier of the virus and infects other chickens. The same applies to birds vaccinated with live ILT vaccines. When such individuals are introduced into an unvaccinated herd, outbreaks of the disease occur.

The ILT virus is not transmitted through the egg, but it can remain on the shell. Eggs from sick hens cannot be incubated, but can be eaten.

The virus is sensitive to disinfection, its resistance in the external environment is low - it can persist for several weeks on care items, clothing of attendants, feeders and drinkers, and in litter.

Symptoms of the disease

More often, infectious laryngotracheitis manifests itself in the autumn and spring, when temperature fluctuations weaken the respiratory tract of chickens and general immunity. Contribute to infection such factors as high humidity and dustiness of the air, poor ventilation, unbalanced feeding.

The incubation period is short and is 1-3 days. In an acute course, up to 80% of the livestock suddenly fall ill, and the mortality of chickens reaches 50-60%.

With subacute disease, the disease spreads throughout the herd within 7-10 days, covering up to 60% of the birds, and up to 20% can die. Often, ILT becomes chronic with a 1-2% loss.

Symptoms of the disease are always associated with damage to the respiratory tract:

• wheezing, coughing, wheezing;
• discharge from the eyes and nose;
• when squeezing the trachea with fingers, a cough occurs;
• when examining the larynx, redness, swelling, pinpoint hemorrhages, accumulation of mucous or curdled masses in the lumen of the larynx are visible.

Chickens are oppressed, eat poorly, cyanosis of the comb and earrings is noted. Usually the bird gets sick within 14-18 days.

Symptoms of laryngotracheitis are sometimes in the conjunctival form. The eyes become inflamed, foamy and or mucous discharges are visible, the third eyelid crawls over the eyeball. After the disease, the bird goes blind due to damage to the cornea. This course of infection is observed in chickens aged 20-40 days and covers up to 50% of the population. At the same time, symptoms of respiratory tract damage are present in a small number of chickens - a few percent.

When a dead bird is opened, a characteristic sign is a strong reddening of the trachea, the mucous membrane is swollen, dark cherry in color throughout, often the lumen of the trachea is clogged with a blood clot. The lungs and air sacs are affected to a small extent, unless the virus has been joined by infection - colibacillosis, mycoplasmosis, and so on.

The diagnosis is made on the basis of isolation of the ILT virus from the pathological material. The disease must be differentiated from b. Newcastle, infectious bronchitis of chickens, respiratory mycoplasmosis, hemophilia, chronic pasteurellosis.

Treatment and prevention

Vaccination during an outbreak of ILT is useless, the introduction of an additional dose of the virus only aggravates the situation. When using this method, it is taken into account that in the future it will be necessary to regularly vaccinate the newly arriving livestock against ILT, since the virus will forever remain on the farm.

The treatment itself is impractical, an economically justified way out of the situation would be the slaughter of the entire herd, disinfection and the importation of new livestock. If this is not possible, then they resort to methods of partial recovery: a clearly sick and emaciated bird is culled, the rest is treated.

Therapy

Treatment of laryngotracheitis is nonspecific. Chickens provide good feeding, heating and ventilation of the house. Next, drugs are used.

• To suppress concomitant bacterial infections, broad-spectrum antibiotics are drunk: enrofloxacin, norfloxacin, ciprofloxacin, tetracyclines. Furazolidone powder can be mixed into the feed at the rate of 8 g per 10 kg of feed.
• Apply a solution of gentamicin aerosol by spraying from a sprayer.
• Lactic acid or iodotriethylene glycol is sprayed with an aerosol generator to disinfect the poultry house in the presence of birds.
• Disinfection can be done by sublimation of chlorine turpentine at the rate of 2 grams of bleach and 0.2 grams of turpentine per 1 cubic meter. volume of the room, exposure 15 minutes.
• Drink solutions of complex vitamins - "RexVital", "Chiktonik", "Aminivital", "Nitamin" and the like.
• In a wet mash add the drug "ASD-2" at a dose of 1 ml per 100 animals.

Measures to prevent infectious laryngotracheitis come down to preventing the introduction of the virus into the farm and vaccination.

In prosperous areas, it is strongly not recommended to vaccinate chickens - this way you will bring the virus to the farm for many years.

In practice, vaccination is necessary only in two cases:

• when importing vaccinated poultry from another farm;
• during an outbreak of infection and subsequent partial recovery of the herd.

There are not so many vaccines against ILT. In a rural farmstead, it is advisable to use live vaccines. The best method of vaccination is to drip into the eye. The cloacal method is less effective, and watering gives a large percentage of non-immune individuals.

Birds are immunized upon arrival at the farm or at the age of 30-60 days. Chickens older than 60 days and adult chickens are vaccinated once, younger ones - twice with an interval between vaccinations of 20-30 days.

Overview of Vaccines

What do you need to know about ILT vaccines in general? There are two types of these drugs.

1. Vaccines produced on chick embryos. They provide strong protection, but can cause serious complications.
2. Cell culture vaccines. Post-vaccination reactions do not cause, but give lower protection.

Vaccines against ILT are available from all leading manufacturers. Here are some drugs recommended for use in laying hens and broilers. The minimum packaging in a vial for most companies is from 1000 doses.

• Embryo-vaccine against infectious avian laryngotracheitis "Avivak ILT", Russia.
• Virus-vaccine dry against infectious laryngotracheitis of birds from the strain "VNIIBP". "VNIVIP", Russia.
• Virus vaccine against infectious laryngotracheitis of birds from the strain "VNIIBP". "Pokrovsky Plant of Biopreparations".
• Nobilis ILT (Nobilis ILT). Live dry vaccine against infectious avian laryngotracheitis with solvent. Intervet, the Netherlands.
• Bird vaccine against infectious laryngotracheitis AviPro ILT. "Lohmann Animal Health", Germany.

conclusions

Infectious laryngotracheitis is a serious viral disease. Chickens of all ages are susceptible to it. The main route of infection is the importation of infected or vaccinated birds to the farm, so special attention is paid to completing the herd.

When a disease occurs on the farm, the best way to fight is to slaughter all the birds, disinfect and bring in new livestock. True, for such an extreme measure, it is necessary to clearly know the diagnosis - to isolate the virus in the laboratory, which is not always possible in a private compound. Therefore, the method of partial recovery of the herd is used - a weak bird is culled, and the rest is treated.

The decision on further vaccination should also be made on the basis of the diagnosis made by the doctor - once you enter the vaccine into the farm, you will be forced to bear the cost of vaccination throughout the entire existence of the farm.

As the name suggests, it's viral. chicken disease affects the mucous membrane of the larynx and trachea. Sometimes concomitant symptoms are conjunctivitis and nasal lesions. If the disease is not cured in time, you can lose a lot of your domestic laying hens. Consider laryngotracheitis in chickens, the treatment of which is so important to start on time and correctly.

Description

Laryngotracheitis is a dangerous infectious disease that causes the activity of viruses from the herpes order. As practice shows, it is quite stable, therefore, after the incubation period, it can remain active for up to two years. In addition to chickens, all poultry, as well as pigeons, suffer from this disease.

Laryngotracheitis in chickens occurs in two main forms: acute and hyperacute. At the same time, the acute course of the disease causes mortality in 15% of cases, while the hyperacute form - in 50-60% of cases. In some animals, the disease occurs in a chronic form of manifestation.

Of all poultry, and especially chickens aged 30 days - 8 months, are the most susceptible to the disease. It is important to note that the virus is also transmitted to humans if they often come into contact with infected birds. A person can be affected by the larynx and trachea, the skin of the hands, and also develop bronchitis due to the disease.

As for chickens, laryngotracheitis most often manifests itself during periods of unstable temperatures, off-season, in case of non-compliance with sanitary standards, and also with low bird immunity. Old and adult birds that have been ill at an early age acquire immunity, so they no longer get sick. But they are carriers of the virus. The main route of infection is airborne.

Symptoms of manifestation

As we have already said, laryngotracheitis occurs in chickens in two phases - acute and hyperacute. The latter form often occurs suddenly in disadvantaged farms, where the disease has not been previously recorded. In this case, almost all chickens (up to 80%) can become infected in the first day. The main indicator of this ailment is the heavy, almost impossible breathing of a bird. After there is a cough, asthma attacks, spitting. Birds that have recovered from illness can still wheeze for a long time, suffer from conjunctivitis, although they will look healthy outwardly.

Symptoms of the hyperacute form

• asthma attacks;
• chickens shake their heads;
• cough with blood or other secretions;
• low mobility of birds;
• swelling of the larynx and the presence of curd secretions on the mucous membrane;
• lack of appetite and oviposition;
• wheezing.

Symptoms of an acute form of the disease

Acute laryngotracheitis also affects the respiratory organs and spreads in the herd in about 10 days. Mortality in these cases with proper treatment is low, does not exceed 20%. Characteristic signs:

• poor appetite;
• lethargy and inactivity;
• wheezing and whistling when breathing;
• cough;
• swelling of the larynx;
• the presence of curdled secretions.

In chickens, laryngotracheitis is also accompanied by a severe form of conjunctivitis. Many even lose their sight.

Treatment Methods

If laryngotracheitis is detected in chickens, treatment should be carried out immediately. However, we note that a drug to combat the disease of birds has not yet been created. Various antibiotics are used in practice, which can only reduce the activity of the virus. For example, the use of biomycin reduces overall mortality. When taking medications, laying hens should definitely receive additional vitamins in the diet, in particular A and E.

The basic rule for laryngotracheitis is good prevention, which consists in proper feeding of birds, as well as in strict adherence to sanitary and hygienic standards. To disinfect the chicken coop, a mixture of chlorine-turpentine is used. Also, as a prevention of the disease on large farms, special vaccines are used.

Video "Some rules for broiler vaccination"

Laryngotracheitis in chickens is an acute viral disease that affects the mucous membranes of the eyes, nose, pharynx, trachea with a predominantly hemorrhagic-catarrhal lesion.

There is no effective etiotropic treatment of laryngotracheitis. Symptoms and treatment are closely related, and all therapy is treatment to alleviate the condition of the bird.

Basic principles of therapy:

1. Mandatory change in the conditions of the poultry house: decrease in humidity, the room should be warm, good lighting. Replacement of bedding, disinfection of drinkers, feeders, enrichment of the diet.
2. To prevent the attachment of microorganisms, broad-spectrum antibiotics are prescribed - tetracycline, enrofloxacin.
3. The room is treated with a spray containing lactic acid.
4. The oropharynx is treated with solutions with gentamicin and furozolidone preparations.
5. The diet includes vitamin complexes: Chiktonik, Nitamin.
6. ASD-2 is used as an immunomodulator.

Prevention

The main aspect in preventing epidemics of laryngotracheitis is compliance with the conditions for introducing poultry to the farm. The collection of eggs for breeding and the purchase of poultry should be carried out from prosperous farms.

• Conditions of detention are also required: a dry, warm room with good ventilation. Overcrowding of birds is unacceptable, and it is also recommended to divide the livestock by age.
• If the content is carried out without walking, then it is imperative to treat the house, as well as disinfect the air to free it from respiratory viruses.
• It is also timely to deal with the appearance of rodents, which are mechanical carriers of dangerous infectious diseases.

In the event of an outbreak, it is strictly prohibited to:

1. Movement of domestic birds inside the farm.
2. Import and export of poultry from the territory of the farm, as well as the sale of eggs for incubation
3. Moving inventory, feeders and waste outside the farm.
4. Persons must not enter or leave the territory of the farm without prior complete sanitization of clothing.

Important: Affected eggs and meat are allowed to be exported for the purpose of sale after appropriate disinfection measures. Possibility of selling down and feathers.

Laryngotracheitis of chickens, when first occurring on a farm, leads to the complete slaughter of the entire batch of poultry in order to prevent repeated outbreaks. Quarantine is removed after two months from the moment of death of the last diseased individual.

Vaccination and drug review

If there is no outbreak of infection on the farm, then the birds are not vaccinated, since the chicken becomes a carrier of the virus and infects healthy compatriots.

The most famous option for vaccinating individuals is live serum droppers. In second place in popularity is the cloacal introduction.

Immunization is carried out at the initial stages of detection of laryngotracheitis. Young animals up to 2 months old are vaccinated 2 times with an interval of 1 month; for adult laying hens, one injection is sufficient. The duration of post-vaccination immunity ranges from 7 months to a year.

There are 2 types of drugs:

1. isolated using chick embryos.
2. Obtained in cell culture.

In the first case, the vaccine has the greatest effect, but is manifested by serious side effects. Preparations on cell culture have a lower immunization of livestock, but without clinical manifestations of complications.

Avivak is a Russian-made vaccine, which is classified as an embryonic type.

VNIIBP - dry preparation. isolated from a virus strain. Produced by a Russian company.

AviPro is a German live vaccine.

All medicines are produced with dosages of at least 1000 doses in a vial.

Symptoms of laryngotracheitis in chickens

The infection is divided into three main forms of the course:

1. Classical - laryngotracheal.
2. Conjunctival.
3. Atypical.

All forms are characterized by an incubation period, which ranges from a couple of days to 1 month. But the peak of clinical manifestations after infection occurs within 3-7 days.

According to the course of the disease, there are:

1. Sharp shape.
2. I'll sharpen the form.
3. Chronic course.
4. Asymptomatic course (virus carrier).

Laryngotracheal form

In the acute course, vivid clinical manifestations are observed first in individual laying hens, and within a week the disease captures the entire group of birds.

The disease begins with a general deterioration in well-being:

• Drowsiness;
• lethargy;
• Apathy;
• Catarrhal phenomena;
• Respiratory damage.

Main symptoms:

1. Cough, respiratory failure: wheezing, wheezing. More often they appear in the evening or at night, when croaking, whistling wheezing breathing is clearly audible from perches in silence.
2. Mucous and bloody discharge from the nose and throat.
3. Difficulty breathing in and out. The beak is constantly open, and when pressed into the trachea, a paroxysmal cough begins with the release of sputum with blood streaks.
4. On examination, swelling, redness of the pharynx are noticeable, and in advanced cases, a curdled plaque may appear on the larynx.
5. Hens stop laying eggs.

The lethal outcome depends on the conditions of detention and ranges from 10 to 60 percent of the total poultry population.

In the subacute course of the disease, the symptoms are less pronounced. Blood exudate, edema, sharp hyperemia of the larynx is not observed. The bird develops a cough, difficulty breathing, and a decrease in egg production. Anemia is manifested - blanching of earrings and comb. On examination, a fibrinous gray coating is found in the pharynx, which is easily removed.

conjunctival form

With this type of disease, the main affected area is the mucous membrane of the eye. In chickens, redness and narrowing of the slit of the eye, mucous flow, swelling of the eyelids are observed.

This form is most susceptible to two-week-old chickens, which, when kept together with adults, infect the entire population.

Main symptoms:

1. Eye damage: edema, photophobia, lacrimation. When exudate appears, the eyelids stick together, the form is complicated by keratitis and panophthalmia with loss of vision.
2. Temperature increase.
3. The defeat of the sinus node and the appearance of currents from the nose.

Usually, conjunctival laryngotracheitis lasts up to 3 months and greatly reduces the population of young animals. The form with eye damage occurs on farms with increased indoor dampness, an increased concentration of ammonia fumes in the air.

Atypical form

Occurs in conjunction with bronchitis or mycoplasmal infection. The symptoms are varied and masquerade as many types of respiratory infections.

This form is isolated only with a serological blood test, after which a diagnosis of laryngotracheitis is made.

Diagnosis at pathoanatomical autopsy

The main clinical diagnosis is based on the symptoms of the disease and the autopsy of chicken carcasses.

Laboratory methods must also be used:

• Serological examination of serum for the detection of antibodies;
• Isolation of the virus from the exudate from the trachea and mucous membranes;
• Isolation of a biopsy specimen from the mucosa to detect intracellular round-shaped inclusions of the virus with bright rims.

Up to 5 heads of live laying hens, as well as carcasses for autopsy, are delivered to the laboratory for the study of poultry from the entire stream.

Pathological changes

All changes affect the respiratory system: larynx and trachea, without damaging other organs.

Symptoms:

1. The mucosa has a bright hyperemia, edematous, with pinpoint hemorrhages.
2. Fibrinous-necrotic plugs protrude on the larynx, which close the lumen, causing death as a result of suffocation.
3. In the trachea there is a large amount of mucus with bloody secretions.
4. There is a grayish coating in the oral cavity, which is easily separated.

In rare cases, foci of necrosis are found in the lungs of a dead bird.

Differential Diagnosis

Usually, a comparison is made with pseudoplague, group A beriberi (conjunctival form), mycoplasmosis, smallpox and viral bronchitis of chickens.

Peculiarities:

1. Pseudoplague is a characteristic lesion of the intestines, ulcers in the stomach with pathognomic rashes in the form of hemorrhagic rings on the mucous membranes.
2. Mycoplasmosis affects the lungs. Rarely leads to death.
3. Hypovitaminosis A is not expressed by asthma attacks.

It is difficult to distinguish the disease from smallpox, the diagnosis is possible only with the connection of serological diagnostics and isolation of the virus.

Main routes of infection

Pheasants, chickens, and turkeys are most at risk among domestic birds. More often, the virus affects young animals of six months of age.

With high crowding, monthly chickens can get sick:

1. The main sources of infection are sick birds and virus carriers. On the farm, the disease spreads through contaminated feed, water, contaminated bedding, on the clothes of workers. The virus is shed by sneezing, coughing, or by mechanical transmission along with rats or wild birds.
2. If a bird has been ill with laryngotracheitis, then it releases virions into the environment for more than 2 years. Such a bird must be culled, otherwise the disease becomes a permanent inhabitant of the farm, infecting young birds.
3. Be sure to take into account the carriage of the virus after vaccination, it persists for about 2 weeks after the introduction of serum.

If the eggs are raised properly in the incubator, newborn chicks are resistant to the virus.

The main reasons for the outbreak of the epidemic are the deteriorating conditions of detention:

• Poor ventilation;
• Malnutrition;
• Excess moisture.

Pathogenesis

The virus enters the body through damaged mucous membranes of the nasopharynx, larynx and eyes, causing an acute inflammatory process. The greatest compatibility of the virus with the epithelial lining of the respiratory organs, where the main factors of division and growth occur.

Such local exposure to virions causes lymphatic edema of tissues and the appearance of exudative secretions. With the development of the disease due to damage to the membranes of the respiratory tract, they turn into hemorrhagic.

Despite the spread of infection through the bloodstream, other organs are not subject to pathological changes, and the whole process is localized in the larynx and trachea of ​​laying hens.

It is possible to attach a secondary bacterial infection, which begins to develop when necrotic plugs occur in the larynx.

A bit of history

For the first time, the disease was brought into a separate unit in 1925 in the United States. Before the discovery, the disease did not differ from viral bronchitis. It was considered one disease.

The economic damage from the virus ranges from 10 to 30% as part of the reduction in egg production and weight gain in laying hens. When accounting for poultry deaths, costs vary.

And the frequency of deaths from the entire mass is from 15 to 50%. Also, poultry farms are financially hurt by the costs of stopping the infection among the general flow of chickens.

Etiology

The causative agent of infectious laryngotracheitis in chickens belongs to the family of herpes viruses, which are rounded virions of the order of 100-250 nm in diameter.

The large variation in size is explained by fluctuations in the growth of virions in different environments: there are more of them in the cytoplasm of the cell than in the nucleus. The virus itself is DNA-containing, resistant to low temperatures. It is stored in poultry carcasses for more than 1 year in a frozen state.

But the infection is poorly susceptible to elevated temperatures. When boiled, virions die instantly, and when treated with chlorine-containing agents - within 30 seconds.

Laryngotracheitis in chickens is a viral disease that affects the lining of the larynx and trachea. Additional symptoms are the occurrence of damage to the conjunctiva of the eye and nasal mucosa. With untimely treatment, a significant loss of livestock is observed.

What is laryngotracheitis in chickens

This disease is infectious and quite dangerous. It occurs due to the entry of viruses into the body. The virus is stable, after passing the incubation period it lives for several years in a fairly active state. Not only domestic chickens can suffer from laryngotracheitis, but also other poultry. Larengotracheitis has two main forms: acute and superacute.

The acute course of this disease brings up to 15% mortality of livestock, over acute can be up to 60% of the case. Sometimes this disease can occur in a chronic form. The most susceptible to this disease are young animals aged from 4 weeks to 8 months. This disease is dangerous to humans, the virus can be transmitted through contact with a sick bird.

Signs of infection with laryngotracheitis from chickens in humans

The larynx, trachea, and also the skin of the hands are affected, bronchitis develops. This disease is especially prevalent during periods of large temperature fluctuations between seasons with insufficient cleanliness in the hen house and with a low immune system in birds. A bird that has been ill with laryngotracheitis is immune and is no longer predisposed to this disease. But such a bird can be a carrier. The main route of transmission of the disease is airborne.

Symptoms of laryngotracheitis in chickens

Laryngotracheitis occurs in 2 forms: acute and super-acute, it must be understood that the super-acute form is formed only in those farms where the disease was previously detected and they are considered unfavorable for this disease. In the first days, infection occurs up to 80% of the total livestock. The main symptom of laryngotracheitis in chickens is the appearance of very difficult breathing difficulties. Further coughing, choking, expectoration is observed. A bird that has been ill with this disease can wheeze for a long time and suffer from inflammation of the conjunctiva of the eye.

Symptoms of over-acute course of laryngotracheitis in chickens

First, attacks of suffocation appear, head shaking, a cough appears with bloody and other secretions, the larynx swells, cottage cheese discharge appears on the mucous membrane, appetite disappears, egg laying decreases, severe wheezing occurs.

Symptoms of an acute course of laryngotracheitis in chickens

In the acute form of the course, the respiratory organs are affected, spread throughout the livestock occurs within a week. If there is a rapid detection of the disease and the correct treatment is carried out, then the mortality rate is low, usually does not exceed 20%. Signs indicating laryngotracheitis are a decrease in appetite, inactivity, a lethargic state, when breathing in birds, hoarseness and whistling are heard, a cough is observed, when the larynx swells, there are cottage cheese discharges, the conjunctiva swells. Sometimes, with untimely treatment, the bird may lose its sight.

How to treat laryngotracheitis in chickens

With this disease, the speed of treatment is important. For this disease in the poultry industry, there is not yet the necessary drug for treatment, but broad-spectrum antibiotics that reduce the activity of the virus can be used. An antibiotic such as biomycin significantly increases the safety of the livestock; when using these drugs, it should be remembered that they are given in conjunction with vitamins. It is better to prevent this disease, so prevention is necessary, which includes a balanced nutritional diet and compliance with sanitary and hygienic standards in the chicken coop. Also, in the room where the bird is kept, periodic disinfection is carried out using a mixture of chlorine and turpentine. At large poultry enterprises, a special vaccine against laryngotracheitis is used as a prophylaxis.