Infectious Bronchitis (IB) in poultry is an acute and highly contagious respiratory disease caused by the Infectious Bronchitis Virus (IBV), which widely affects chickens, especially laying hens and broilers. The disease not only causes respiratory symptoms, but may also cause decreased egg-laying performance and kidney damage, causing significant economic losses to the poultry farming industry. This article will introduce in detail the etiology, symptoms, diagnosis, and scientific prevention and treatment options of infectious bronchitis in poultry to help farmers effectively deal with this disease.
Etiology of infectious bronchitis
Pathogen: IBV belongs to the family of Coronaviruses (Coronaviridae) and is a single-strand positive-strand RNA virus. The virus has a variety of serotypes (such as M41, Conn, Ark, etc.) and genotypes, which increase the difficulty of prevention and control because of its variability.
Susceptible groups: Chickens of all ages can be infected, but chicks and laying hens are particularly affected.
Infectious bronchitis (IB) is a highly contagious viral disease that affects chickens of all ages and types. The pathogenic organism is a single-stranded RNA virus of the coronavirus family, which mainly affects chickens. It affects the upper respiratory tract, the reproductive tract of female chickens, and some strains cause nephritis. Different serotypes and genetic types of viruses have been identified all over the world, and in most cases there is no cross-protection. The virus is present in commercial chickens and backyard chickens. Recently, IBV and IBV-like strains have been found in poultry other than chickens, such as geese, ducks and pigeons, and may also play a role in the spread of IBV strains around the world.
How infectious bronchitis spreads
This disease is spread by infection with droplets in the air, from poultry to poultry. Although the frequency of airborne transmission is not known, there is some evidence of transmission exceeding 1Km. The virus may also be spread through contaminated materials and equipment, as well as feces.
The place where the eggs are laid may lead to the excretion of the virus, which may have previously been dormant in the host poultry. The occurrence of infectious bronchitis may also be related to an increased risk of feather pecking in free-range systems.
Clinical symptoms of infectious bronchitis
Chicks are the most affected, although all age groups are susceptible.
1.Respiratory symptoms
a. Coughing, wheezing, and nasal secretions increase.
b. Open the mouth and breathe, accompanied by a “cackle” or wet sound.
c. Conjunctivitis, tears or moistness around the eyes.
2.Production performance degradation
a. Laying hens: the egg production rate decreases (up to 20%-50%), and the quality of the eggshell deteriorates (such as thin shells, soft shells, and deformed eggs).
b. Broilers: the growth rate slows down and the feed conversion rate decreases.
3.Kidney type symptoms
(Some strains) Urate deposits, manifested as “spotted kidney”, accompanied by dehydration and mental malaise.
4.Secondary infection
If E. coli or mycoplasma infection is secondary, it may worsen the condition and lead to an increase in the mortality rate (ranging from 5% to 30%).
The course of the disease is usually 7-14 days, but the virus can lurk for a long time, increasing the risk of recurrence.
Preventive measures for infectious bronchitis
The live attenuated vaccine used to immunize IBV can produce mild respiratory signs. These vaccines are initially applied to chicks between 1 and 14 days old by spray, drinking water or eye drops, and breeders usually re-inoculate chickens about 2 weeks after the initial vaccination. Re-vaccination with different serotypes can induce broader protection. Live attenuated vaccines or inactivated adjuvant vaccines can be used by breeders to prevent egg loss and to pass protective maternal antibodies to offspring.
There are many different types of IBV, and new or variant types that are not fully controlled by existing vaccines are relatively frequently identified. Mutant viruses historically arise from mutations that accumulate over time as the virus replicates (genetic drift). However, recombination in coronaviruses may lead to unique viruses that may not cause disease. The choice of vaccine should be based on an understanding of the most prevalent types of viruses in a particular geographic area. The correlation between IBV type and protection is imperfect, and the selection of the most suitable vaccine or combination vaccine may require in vivo experimental evaluation. The most commonly used live IBV vaccines in the world contain derivatives of the Massachusetts strains M41, H120, and H52. In addition, several types of IBV vaccines against mutated viruses in specific geographic areas, as well as live and killed autologous vaccines, are licensed for use in various countries.
Wixbio vaccination program
Wixbio provides two types of attenuated vaccines and inactivated vaccines. You can consult your veterinarian according to the prevalence of local strains, and we will provide you with appropriate recommendations.
Broiler vaccination program
1 day old: the first dose of live attenuated vaccine (Ma5, 4/91, QXL87)
7 days old: the second dose of live attenuated vaccine (Ma5, 4/91, QXL87)
Wixbio offers Infectious Bronchitis Vaccine in live chicken vaccine for IB disease.
Vaccination program for laying hens
1 day old: the first dose of live attenuated vaccine (Ma5, 4/91, QXL87)
7 days old: the second dose of live attenuated vaccine (Ma5, 4/91, QXL87)
21 days old: the third dose of live attenuated vaccine (Ma5, 4/91, QXL87)
35 days old: the fourth dose of live attenuated vaccine (Ma5, 4/91, QXL87)
Wixbio’s inactivated chicken vaccines include multiple multiplex vaccines, all of which can be used for the prevention of IB disease in chickens. Multiple vaccines are more economical.
Diagnosis of infectious bronchitis disease
Antibody titers are detected by ELISA or hemagglutination inhibition (HI), and RT-qPCR is used for virus detection and identification. Because it is similar to the mild forms of disease caused by pathogens such as Newcastle disease virus, avian-to-pneumonia virus, infectious laryngeal tracheitis virus, Mycoplasma and Ornithobacter sinus, the respiratory form of infectious bronchitis requires laboratory confirmation to be diagnosed. Through ELISA, HI or virus neutralization tests show seroconversion or increased titer of antibodies against IBV, which can be used for diagnosis in the case of a history of respiratory diseases or reduced egg production.
A clear diagnosis of infectious bronchitis is generally based on virus detection and identification. IBV can be isolated by inoculating homogenates of trachea, cecum, tonsils, and/or kidney tissue into 9-11-day-old SPF chicken embryos. The growth of IBV is indicated by embryonic stunting and curling, as well as the deposition of urate in the mesonephrine. Coronavirus has several structural proteins, the largest of which is called spike glycoprotein. The S1 region of spike glycoprotein can be used to determine the genetic type of the virus, which is related to the virus serotype. RT-PCR products derived from this region can be analyzed by nucleotide sequencing, and then the derived amino acid sequence can be compared with the sequence in GenBank to determine its correlation with known strains.
Treatment of infectious bronchitis disease
There are currently no special antiviral drugs. Treatment is mainly based on relieving symptoms, controlling secondary infections and supporting therapies, although supportive treatment with antibiotics to control secondary infections may be beneficial. The spread rate can be very fast, so infected chickens should be isolated to prevent the spread of the disease. Supportive treatment, such as raising the temperature of the house by 3-4°C, may reduce the mortality rate of infected chickens. In addition, reducing the protein concentration in feed and providing electrolytes in drinking water can help outbreaks caused by nephrotic strains. Improving ventilation and reducing ammonia levels are also beneficial for infected chickens.
Summary
Infectious bronchitis in poultry is a complex and changeable disease, and its prevention and control require comprehensive vaccination, scientific management and timely treatment. Farmers should formulate personalized plans based on the age of the flock, the production stage and the local epidemic, paying special attention to the selection of vaccines and the timing of vaccination. At the same time, a good breeding environment and biosecurity measures are the basis for reducing morbidity.Through prevention-based and treatment-supplemented strategies, the harm of IB to chickens can be effectively reduced and the benefits of breeding can be guaranteed.
FAQ
Will people be infected with infectious bronchitis?
Infectious bronchitis (IB) is a poultry disease caused by the infectious bronchitis virus (IBV), which mainly infects the respiratory system and reproductive system of chickens. The virus spreads through the respiratory tract and may cause serious economic losses in farms, but there is currently no evidence that IBV can infect humans. When humans come into contact with poultry, they need to pay attention to routine hygiene and protection (such as washing hands and avoiding direct contact with sick poultry), but there is no need to worry about contracting IBV.
Can dogs be infected with infectious bronchitis?
IBV is not contagious to dogs, and there is currently no evidence that dogs can infect or spread avian IBV. If a dog comes into contact with sick poultry, it is necessary to pay attention to routine hygiene (such as cleaning its paws and mouth), but there is no need to worry about contracting IBV.
