Infectious laryngotracheitis in chickens: be on strict guard in winter and spring
Strictly prevent infectious laryngotracheitis in chickens in winter and spring
(Agricultural Wealth Network) Infectious laryngotracheitis in chickens is an acute respiratory infectious disease caused by a herpesvirus. It is characterized by difficulty breathing, coughing, and coughing up exudate containing blood. The disease spreads quickly and has a high mortality rate, endangering the development of the chicken farming industry.
The disease can occur in all four seasons, but it occurs more frequently in winter and spring.
Pathogen The infectious laryngotracheitis virus mainly exists in the tracheal tissue and exudate of sick chickens. The virus has very weak resistance to the external environment: it survives 22-24 hours when heated to 37°C, survives 10-15 minutes at 55°C, and dies immediately after water is boiled. Disinfection with 3% Lysol or 1% caustic soda disinfectant solution can kill it in 1 minute.
Epidemic characteristics Under natural conditions, this disease mainly affects chickens, and chickens of all ages and breeds can be infected, but the symptoms are most characteristic in adult chickens. Sick chickens and recovered virus-carrying chickens are the main sources of infection, generally through the respiratory tract and within the eyes. Litter, feed, drinking water, and equipment contaminated by respiratory organ and nasal secretions can become transmission vectors.
Once this disease is introduced into a chicken flock, it spreads rapidly, and the infection rate can reach more than 90%. The mortality rate varies depending on feeding conditions and flock status: the low rate is about 5%, and the high rate can reach 50%-70%.
Clinical symptoms The incubation period of natural infection is 6-12 days. In the early stage, sick chickens have nasal discharge, which is semitransparent, and watery eyes, accompanied by conjunctivitis. Afterward, characteristic respiratory symptoms appear, namely moist rales when breathing, coughing, and wheezing sounds. Sick chickens crouch on the ground or on perches. With each inhalation, the head and neck are extended forward and upward, the mouth is opened, and they assume a posture of trying hard to inhale, with wheezing calls. In severe cases, there is severe difficulty breathing, spasmodic coughing, and bloody mucus may be coughed up. If the secretions cannot be coughed out and block the trachea, the chicken may die of suffocation. Sick chickens have reduced or lost appetite, rapidly become emaciated, the comb turns purple, and sometimes greenish thin feces are passed; ultimately most die from exhaustion, and laying hens rapidly reduce or stop egg production. The course of the disease is 5-10 days or longer; those that do not die mostly recover after 8-10 days, and some may become virus-carrying chickens.
Prevention and control measures When the disease occurs, symptomatic treatment can be given, and antibacterial drugs can be used to prevent secondary infection. Feeding management equipment and chicken houses must be disinfected. Recovered chickens must not be raised in mixed flocks with susceptible chickens. In areas where this disease is prevalent, chickens can be immunized by eye-drop inoculation with an attenuated vaccine. The first immunization time is around 4 weeks of age, and a second immunization is carried out after 6 weeks.
[Prescription 1]: Streptomycin 50,000-100,000 units by injection. Usage: intramuscular injection once, 2 times daily, for 3-5 consecutive days. When there is difficulty breathing, 0.5-1 mL of 20% camphor water injection can also be given intramuscularly once.
[Prescription 2]: Moroxydine 20-40 grams. Usage: mix into 100 kg of feed for oral feeding, for 3-5 consecutive days.
[Prescription 3]: 1 dose of attenuated vaccine for preventing infectious laryngotracheitis in chickens. Usage: eye drop and nasal drop at 30 days of age. Note: because vaccination can make chickens carry the virus, this prescription is used only in areas where the disease is prevalent.
The disease can occur in all four seasons, but it occurs more frequently in winter and spring.
Pathogen The infectious laryngotracheitis virus mainly exists in the tracheal tissue and exudate of sick chickens. The virus has very weak resistance to the external environment: it survives 22-24 hours when heated to 37°C, survives 10-15 minutes at 55°C, and dies immediately after water is boiled. Disinfection with 3% Lysol or 1% caustic soda disinfectant solution can kill it in 1 minute.
Epidemic characteristics Under natural conditions, this disease mainly affects chickens, and chickens of all ages and breeds can be infected, but the symptoms are most characteristic in adult chickens. Sick chickens and recovered virus-carrying chickens are the main sources of infection, generally through the respiratory tract and within the eyes. Litter, feed, drinking water, and equipment contaminated by respiratory organ and nasal secretions can become transmission vectors.
Once this disease is introduced into a chicken flock, it spreads rapidly, and the infection rate can reach more than 90%. The mortality rate varies depending on feeding conditions and flock status: the low rate is about 5%, and the high rate can reach 50%-70%.
Clinical symptoms The incubation period of natural infection is 6-12 days. In the early stage, sick chickens have nasal discharge, which is semitransparent, and watery eyes, accompanied by conjunctivitis. Afterward, characteristic respiratory symptoms appear, namely moist rales when breathing, coughing, and wheezing sounds. Sick chickens crouch on the ground or on perches. With each inhalation, the head and neck are extended forward and upward, the mouth is opened, and they assume a posture of trying hard to inhale, with wheezing calls. In severe cases, there is severe difficulty breathing, spasmodic coughing, and bloody mucus may be coughed up. If the secretions cannot be coughed out and block the trachea, the chicken may die of suffocation. Sick chickens have reduced or lost appetite, rapidly become emaciated, the comb turns purple, and sometimes greenish thin feces are passed; ultimately most die from exhaustion, and laying hens rapidly reduce or stop egg production. The course of the disease is 5-10 days or longer; those that do not die mostly recover after 8-10 days, and some may become virus-carrying chickens.
Prevention and control measures When the disease occurs, symptomatic treatment can be given, and antibacterial drugs can be used to prevent secondary infection. Feeding management equipment and chicken houses must be disinfected. Recovered chickens must not be raised in mixed flocks with susceptible chickens. In areas where this disease is prevalent, chickens can be immunized by eye-drop inoculation with an attenuated vaccine. The first immunization time is around 4 weeks of age, and a second immunization is carried out after 6 weeks.
[Prescription 1]: Streptomycin 50,000-100,000 units by injection. Usage: intramuscular injection once, 2 times daily, for 3-5 consecutive days. When there is difficulty breathing, 0.5-1 mL of 20% camphor water injection can also be given intramuscularly once.
[Prescription 2]: Moroxydine 20-40 grams. Usage: mix into 100 kg of feed for oral feeding, for 3-5 consecutive days.
[Prescription 3]: 1 dose of attenuated vaccine for preventing infectious laryngotracheitis in chickens. Usage: eye drop and nasal drop at 30 days of age. Note: because vaccination can make chickens carry the virus, this prescription is used only in areas where the disease is prevalent.