Diagnosis and prevention of infectious rhinitis in chickens
_ Li Lejun
Chicken infectious rhinitis is a common type of poultry respiratory disease in the breeding process, the main symptom is eye and nasal inflammation, affecting the growth and development of chicks and egg laying rate of laying hens, especially the egg laying rate of newborn chickens will be significantly reduced, which is more harmful.
1 Pathogenic features
The pathogen of infectious rhinitis in chickens is Haemophilus para avian, a blunt, short, gram-negative bacterium with blunt ends. The pathogen has no spores, no flagella and motility, Gram staining is red or pink, is a facultative anaerobic bacteria, generally in the medium containing chicken blood or chocolate plate medium can grow well, the surface of the medium will appear wet, translucent, off-white colonies. The pathogen's tolerance to the natural environment is weak, it dies within a few hours under natural conditions, and it is not heat-tolerant, it can die at 45 ° C for 6 minutes, nor is it resistant to disinfectant, but the pathogen is resistant to drying and low temperatures.
2 Epidemiology
2.1 Susceptible Animals
Chickens of all ages can be infected, with chicks becoming ill at 20 days of age with an incidence of more than 70% and chickens over 14 weeks of age becoming exposed to pathogenic bacteria up to 100%.
2.2 Source of infection
Sick chickens and recessive carrier chickens.
2.3 Routes of Transmission
Haemophilus parapheriophilus will be excreted during the sneezing, coughing and feces of sick chickens, polluting dust, air, feed, drinking water and utensils, etc., healthy chickens will infect the digestive tract after eating pathogenic pollutants, and can also inhale airborne pathogens to infect the respiratory tract.
2.4 Popular characteristics
Infectious rhinitis in chickens can be infected all year round, and due to the low temperature in winter and early spring, the pathogen is easy to survive, and once the disease occurs, it is prone to endemic epidemics, so the winter incidence is higher than other seasons. Because adult chickens have a certain degree of immunity, adult chickens are mostly sporadic after infection.
3 Clinical symptoms
3.1 Infection in breeding chickens
At the beginning of the disease, the body temperature of the sick chicken rises, up to 43 ° C, the sick chicken has poor breathing, the visible mucosa has inflammation, there is purulent discharge under the eyelids, accompanied by a foul odor, runny nose, and the body temperature of the sick chicken returns to normal after 3 days after infection. As the disease progresses, the sick chicken is depressed, stops feeding, the crown is whitish, the feathers are fluffy, the cornea is cloudy, it is difficult to breathe, the water intake decreases, and there is a murmur on the auscultation of the lungs. The course of disease in breeding chickens is 3 to 5 days, and in severe cases, it can be postponed to 14 days, loss of appetite, vision loss or blindness, ovarian development of layer chickens is blocked, and the start of production is delayed. If the sanitary environment of the chicken coop is poor, the elimination rate can exceed 30%.
3.2 Adult chicken symptoms
At the beginning of the disease, the sick chicken is reluctant to move, the eyes are closed for anorexia, the nasal slurry mucus, the nasal cavity has purulent discharge, accompanied by a foul odor, the eyelids appear to varying degrees of edema, and some sick chickens can be swollen along the neck. The egg laying rate of hens decreases, the testicles of roosters shrink, and as the disease progresses, it can be secondary to other diseases in the later stages. Adult chickens have a course of disease of 4 to 18 days and a mortality rate of 15% to 25%.
4 Pathological changes
The lesion location is concentrated in the nose, throat, trachea and eyes, acute catarrhal inflammation of the nasal cavity and sinuses of the sick chicken, swelling of the eyelids, atrophy of the eyeball, purulent or cheese-like necrosis in the nasal cavity, swelling of the throat, swelling and congestion of the tracheal mucosa, and purulent secretions in the eyes and mouth of the sick chicken, which will adhere to the surrounding mucosal tissue. Layer hens have atrophy of their ovaries, follicles are stunted, have symptoms of hematoma, and have many yellow cheese-like secretions in the fallopian tubes. Diseased chickens such as heart, kidney, liver, gastrointestinal and other lesions are not prominent, and there is no food in the digestive tract.
5 Diagnostic methods
Collect diseased chicken eyelid or nasal purulent discharge, made into smear after staining, if the stain is red, it is a gram-negative bacteria, the pathogenic bacteria can not grow well in ordinary agar medium, in the chocolate agar plate medium, co2 is required for culture, 37 °C constant temperature can grow well, if the culture after 24 ~ 48 h in the medium surface has a smooth and moist, light gray translucent small colonies generated, can be preliminarily diagnosed as chicken infectious rhinitis. The disease can be tested for serum plate agglutination experiment, polymerase chain amplification experiment (PCR), enzyme-linked immunosorbent assay (ELISA), and multiple detection methods can be used to better determine the type of pathogen infected in chickens. After the diagnosis is confirmed, the susceptibility test of the paper diffusion method can be carried out on the pathogenic bacteria to determine the drugs with high sensitivity and achieve accurate medication.
6 Prevention and control methods
6.1 Methods of Treatment
Western medicine is mainly for antibiotic treatment, before taking the drug to collect the disease material tissue, isolate and culture the pathogenic bacteria, and then carry out the susceptibility test, with high-sensitivity antibiotics as the treatment drug, which can shorten the treatment cycle and ensure the efficacy. If the farm flock is sensitive to drugs such as gentamicin, streptomycin, enrofloxacin, etc., antibiotic drugs can be injected intramuscularly in an amount about 1.5 times the normal amount, twice a day, for 4 to 6 consecutive injections. At the same time, in order to prevent the secondary infection of sick chickens with other bacterial diseases, 100 g of Tylosin tartrate can be added to the chicken drinking water (1000 kg), and the dosage of the whole day can be drunk within 5 hours, after which the sick chickens can drink freely. Sick chickens that cannot drink water need to be filled with a single dose of 10 mL 3 times a day for 4 to 5 days.
Traditional Chinese medicine treatment can alleviate the disease, and Gu Ben Peiyuan can be combined with Western medicine treatment to promote the recovery of sick chickens. Prescription: Xin Yi 10 g of Nasal Tips, Tulip of Pure Heart and Fire Reduction 10 g, Sand Ginseng of Nourishing Yin and Clearing Lungs 10 g, Zhimu and Huang Cedar of Qing Diarrhea Lung Heat 10 g each, Erhua 80 g of Cool Wind And Heat, Dandelion, Banlan Root and Peppermint 80 g each of Heat and Detoxification, Cang Er Zi of Tong Zhi For Pain Relief 80 g, Bai Zhi of Cold and Dehumidification 80 g, Wood Fragrance of Liver Qi 80 g, Windproof of Wind Removal Table 80 g, Cough and Expectorant Licorice 80 g, Developed into powder, mixed into adult chicken feed (1000 doses), once a day, Continuous medication for 4 to 6 days, while doing a good job of fecal cleaning and disinfection, strengthen the heat preservation and ventilation of the chicken coop.
6.2 Precautionary Methods
6.2.1 Vaccination, improve the disease resistance of the whole herd Chicken infectious rhinitis vaccine mainly includes chicken infectious rhinitis type A oil emulsion inactivated seedlings, chicken infectious rhinitis and chicken Newcastle disease binary inactivated vaccine, chicken infectious rhinitis bivalent oil emulsion inactivated vaccine, etc. If the farm is infected, the uninset chickens can be urgently inoculated with inactivated seedlings, and at the same time, an appropriate amount of sulfonamide drugs or traditional Chinese medicines are added to the drinking water, which can improve the resistance of the whole group and prevent secondary infection. The whole flock needs to drink glucose, table salt or electrolytic multi-dimensional and other anti-stress abilities.
6.2.2 Strengthen management and do a good job in environmental disinfection First, reasonably control the feeding density to prevent poor ventilation of the chicken coop with excessive density, and adhere to the group feeding of different day ages to prevent pathogen cross-infection. Secondly, keep the chicken coop dry and clean, to prevent the breeding of pathogenic bacteria, breeders in and out of the chicken coop need to do a good job of disinfection, replace disinfectant work clothes and shoes and hats, before and after the clothing are disinfected with ultraviolet light, with disinfectant 1 to 2 times a week. Chicken farms are disinfected weekly with 3% sodium hydroxide solution, and chicken manure is uniformly stacked for fermentation. The chicken coop is sterilized with potassium permanganate solution fumigation. Again, the chicken farm should ensure the full in and all out management mode, outsiders and vehicles can not enter at will, to ensure that the chicken farm is quiet, in order to prevent noise from stimulating the chicken flock.
7 Summary
Chicken infectious rhinitis is a type of respiratory disease that often occurs in chicken farms, daily breeding is not done well in hygiene and disinfection management, coupled with poor ventilation in the cold season, the elimination of chicken coop cleaning and disinfection is not thorough, chicken coop will induce secondary infection. Chicken infectious rhinitis is more harmful to layer chickens, will seriously reduce the egg production rate, and chicken infectious rhinitis is easy to recur after cure, only good purification management can fundamentally play a preventive role.