Infectious bronchitis of chickens: pathogen, diagnosis, treatment and prevention measures

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

Infectious bronchitis of chickens is a very dangerous disease, which usually results in the death of part of the herd and a significant decrease in egg production. Currently, IBK is detected in poultry farms, unfortunately, quite often. Preventive vaccination is considered the main measure to combat this disease.

A bit of history

This disease is caused by an RNA-containing virus of the Coronaviridae family. One of the features of the IB pathogen is the ability to rapidly mutate. This causes significant difficulties in the prevention of infectious bronchitis in poultry farms.

For the first time, the IBV virus was isolated by US scientists in 1936. According to some data, this disease was brought to Russia around 1946. At the moment, in the poultry farms of our country, chickens suffer mainly from two strains of the infectious virus chicken bronchitis: Massachusetts and 793B. It is from these two varieties in Russia that the largestnumber of immunological preparations.

Biology of the causative agent of infectious bronchitis in chickens

The Massachusetts serotype was first identified in the 40s of the last century in the US and Europe. This strain mainly affects the respiratory organs of birds. As a result, chickens develop acute respiratory infections, which can lead to their death. 793B causes high mortality mainly in broilers. This strain can affect both the respiratory and genitourinary systems of birds.

These two types of virus are different:

1. Resistant to adverse environmental factors. In drinking water, the IBV virus can, for example, survive up to 11 hours.
2. Resistant to acidic environments. In alkali, IB strains usually die quickly.
3. Relatively resistant to UV radiation. Under its influence, the virus dies in most cases in a day.

At elevated temperatures, the IB virus usually dies fairly quickly. For example, at 50 ° C, this happens in 10 minutes.

What is the danger of the disease?

Both chickens and adult birds can become infected with IBV. Most often, young people suffer from this disease. In chickens, in most cases, the respiratory system is affected. In adult hens and pullets, IBV usually affects the reproductive system. In some cases, chickens may even stop laying altogether.

The danger of infectious bronchitis, in addition to reducing productivity, lies in the high mortality rate of birds. The losses during the epidemic in the economy often exceed 35%. It concerns howyoung and adult birds.

In the event that the infection enters the farm, it will be very difficult to remove it. Even recovered chickens remain carriers of the virus for several months and can transmit it to other individuals. In most cases, IBV in a dysfunctional livestock is not cured, and unfortunately, it becomes chronic.

Causes of the spread of infections

This disease is transmitted mainly from individual to individual. That is, an IB epidemic can break out on the farm, for example, after buying new chickens or pullets. Sometimes the hatching egg also becomes the cause of an outbreak of infectious bronchitis in chickens on the farm. Chicks bred from such material obtained from sick laying hens, in most cases also turn out to be infected.

How is the infection transmitted?

The routes of infection of he althy chickens with infectious bronchitis are as follows:

1. Aerogenic. In this case, the virus is released from the nostrils and beak of a sick bird and is carried by air current.
2. Contact. In this way, the virus is often transmitted in those farms where there is a large overcrowding of chickens.
3. Oral-fecal. Chickens have been known to occasionally eat their own droppings. In this case, infection can also occur very easily.
4. Sexual. A rooster can transmit disease to a hen by covering.

The danger of IBK, therefore, lies, among other things, in large numberspossible routes of infection.

Shapes of flow

Both acute and chronic infectious bronchitis can develop in chickens. These forms of flow in chickens differ mainly only in the degree of severity of symptoms. In acute illness, the latter are more pronounced. In the chronic form, only labored breathing in the bird and discharge from the nose are noticeable.

Most often, chickens on the farm die, of course, from acute IB. However, even in chronic cases, mortality rates can be very high. In some cases, farmers lose up to 30% of the herd with this form of the disease.

Symptoms of the disease when the respiratory system is affected

The incubation period for the IBV virus can last from 36 hours to 10 days. In most cases, the first signs of this disease become noticeable a week after infection. In chickens, the following symptoms of hen infectious bronchitis are commonly seen:

• cough;
• shortness of breath;
• weight loss;
• distortion of the neck;
• conjunctivitis.

The wings of sick chicks usually droop a lot. The chicks themselves look weak and inactive.

Symptoms in an adult bird

In these chickens, the IB virus affects both the respiratory and reproductive systems. The symptoms in an adult bird are the following:

• whistle when breathing;
• diarrhea with green stools;
• essentialdecrease in egg production.

Chickens with infectious bronchitis look lethargic and weak. The shells of the eggs they lay in most cases are soft.

Inexperienced farmers IBV in chickens, unfortunately, is usually not immediately noticed. The symptoms of this disease are mainly respiratory. And therefore, beginners often mistake infectious bronchitis for a common cold.

With a long course of IBK in chickens, among other things, the kidneys are affected and cease to effectively perform their functions. This results in severe diarrhea. If the chicken has already passed the disease to this stage, it will not be possible to save it in any case.

Patological changes

Chickens die with IBV, as already mentioned, quite often. At the same time, the following changes are found in the corpses of such a bird:

• numerous hemorrhages in the trachea and bronchi;
• often - the presence of serous and catarrhal exudate (with inflammation);
• underdeveloped ovaries with signs of hemorrhage in an adult bird;
• ovarian follicle atrophy;
• ovarian cysts.

In the event that infectious bronchitis in a chicken proceeded in severe form, pathoanatomical studies can also reveal swelling of the mucous membranes and infiltration of the epithelium. The kidneys of such a bird in most cases are enlarged in volume and are distinguished by a variegated pattern. Urates are often found in the urinary canals of chickens killed by IB.

Howdiagnosing?

Mixing chicken IBs for the common cold is thus easy enough. To accurately diagnose infectious bronchitis, veterinarians therefore conduct laboratory tests. For this purpose, swabs from the trachea and larynx are taken from the bird. Further, such material is checked for the presence of a virus.

In some cases, serological tests may also be performed during the diagnosis. However, veterinarians:

• do enzyme immunoassay;
• conduct biological molecular research;
• perform indirect haemagglutination.

If infectious bronchitis is suspected in birds, among other things, blood is taken for analysis every two weeks. Research in this case, of course, is also carried out in order to identify the strain of the pathogen.

Treatment of infectious bronchitis in chickens

When IBV is detected on a farm, the first thing to do is to separate the he althy bird from the diseased one. Actually, for the treatment of chickens, the method of general antiviral therapy is usually used. In this case, drugs such as:

• blue iodine;
• Anfluron.

Blue iodine for the treatment of infectious bronchitis of chickens is most often used in the amount of 0.2 or 0.5 ml per head per day. At the same time, it is allowed to give such a medicine to a bird both in its pure form - with food, and diluted with water.

"Anfluron" is also a good answer to the question of how to treat infectious bronchitis in chickens. This drug is used for such a disease, usually in an amount of 0.5-1 ml per day. The course of treatment with this remedy in most cases is a week. Give such a drug to chickens in a dry form orally or make intramuscular injections.

Adequate measures against IBV on the farm should, of course, be taken immediately after the first symptoms of it have been noticed. Both the treatment of infectious bronchitis in chickens and its prevention, however, will be ineffective if the bird is kept in dirty, unventilated rooms. In the chicken coop, if an infection is detected, good ventilation should be immediately ensured. The house also needs to be thoroughly cleaned.

Further, it is mandatory to process the chicken coop with blue iodine. This substance is pre-diluted with water, and then the resulting solution is sprayed into the poultry house. The concentration of iodine in the air in the chicken coop should eventually be 10 mg/m3.

Folk treatments

Chickens get sick with infectious bronchitis, of course, not only on large farms, but also in private households. Summer residents for the treatment of IB can also use various folk methods.

In farmsteads with such a disease, they try to give chickens more greenery - nettles, carrot tops, etc. Also, more vitamin and mineral premixes are added to the poultry mash.

Disease prevention

Unfortunately, the treatment of infectious bronchitis in chickens is often ineffective. IBV viruses are highly survivable and are transmittedin many ways. Therefore, on a poultry farm, it is important to periodically carry out various activities aimed at preventing the spread of this disease.

The most effective preventive measure against IBV is, of course, vaccinations. There are only two main types of vaccines against infectious bronchitis of chickens:

1. Live vaccine. Such preparations are commonly used to vaccinate chickens. Means of this type create early protection for young animals. Immunity to most types of virus in chickens with the use of such drugs is usually developed after 2 weeks. The main disadvantage of this type of vaccines is the risk of mutation of the strains contained in them to wild varieties.
2. Inactivated vaccine. Preparations of this variety are used mainly for pullets and parent stock. When such a vaccine is used, maternal antibodies begin to be produced in laying hens.

Before using the inactivated infectious bronchitis vaccine, chickens are pre-vaccinated with a live vaccine. Moreover, such a procedure is carried out at least 4-5 weeks in advance. Using this technique allows you to provide protection against infection in 95% of cases.

How to prevent outbreaks on the farm?

In addition to vaccination, the following activities are supposed to be carried out on farms to prevent an IB epidemic:

• disinfection of hatching eggs;
• monitoring indoor air quality;
• distribution of birds by age.

It is, of course, necessary to purchase feed and new young animals for the farm only in neighboring farms that are safe in terms of infectious bronchitis. The same goes for hatching eggs.

Certain security measures in terms of the spread of the epidemic, of course, must be observed by the owners of those farms on which IB has already been detected. Such farms are prohibited from exporting and selling live birds, embryos and hatching eggs in the first place. It is also not allowed to move chickens from room to room in such factories. Sperm cannot be taken from sick males in such farms to fertilize hens.