The trend of poultry disease in the world and its control strategy

OA show ('918 '); [trends and control strategies of poultry diseases in the world] 1 New infectious diseases in the past 20 years (1) Salmonella enteritidis (SE) Salmonella infection is not a new problem The harm of Salmonella enteritidis (SE) to poultry industry began in Britain in the late 1980s and soon became a worldwide problem Aerosols in 1991 and 1992 published the economic losses caused by Se in some countries Pattison points out that 234 chicken flocks have been eliminated in the UK, and about 6000 smaller egg farmers have gone bankrupt Karel of the Czech Republic reported the prevalence of bacteriophage-8 Se in the country from January to April 1992 More and more se infections were detected in human feces, resulting in 1496000 infected chickens being slaughtered and countless eggs being destroyed Hoop reported the first se epidemic in Switzerland in 1989, with 3.5 million Swiss francs being used to compensate chicken breeders In Switzerland, the control measures include strict control of imported breeders and layers, and the control of local layers is obligatory Some of the major feed agent distributors have specified inspection requirements for their contract egg suppliers Later, it was reported that the SE infection rate of laying hens in Switzerland decreased, consumer confidence rose, and the SE infection rate of human decreased by 30%, back to the level of 1986 (2) infectious bursal disease with high virulence IBD originated in the early 1960s in the United States (luckert et al., 1997), but there is no highly virulent IBD in America Since the late 1980s, this highly toxic type of IBD has caused serious economic losses in some other regions of the world This highly virulent form of IBD originated in the Netherlands and was reported by chettle et al (1989) Other reports on aerosols show that highly toxic IBD occurs almost simultaneously in many countries Bock of Israel pointed out that the disease began in November 1988 in Israel, usually occurred in 3-5 week old chickens, with a mortality rate of 50% Buys reports that the disease was first discovered in South Africa in a flock of broilers near Cape Town in 1989 Sami Ahmed reports IBD of Broilers and meat populations in Egypt in the summer of 1989 Tanzania was born in 1989 Gagi reported the occurrence of highly toxic IBD in Serbia in 1991 The mode of transmission of the disease is not clear and seems to be related to the import and export of chickens among countries (3) turkey rhinotracheitis (TRT) TRT was first found in South Africa in the late 1970s (buys et al., 1980) and was later identified as a pulmonary virus (Cavanagh et al., 1988) The disease caused serious economic losses to turkey production in Britain There was no TRT in North America before 1996 In 1996, TRT virus was isolated from Turkey in Colorado, USA It caused cough, sneeze and runny nose Its serotype may be different from that of TRT in England and South Africa, and that of chicken swollen head syndrome (cook, 1999) The disease was eradicated in Colorado and then settled in Minnesota (4) Ornithobacterium rhinotrotraceale (or) chin et al (1997) pointed out that or may have existed in chicken flocks for many years, and it was not recognized that it can be used as a primary pathogen until 1980s Bock in Israel and buys in South Africa reported that or became a problem in their country in 1986 and 1991, respectively Buys reported that the symptoms of upper respiratory tract caused by or infection could be recovered within 4-7 days, but the air bag infection continued, resulting in the increase of elimination rate at slaughter Or infection also results in stunted growth, and if accompanied by IBV, NDV or rhinotracheitis virus infection, there will be a high mortality rate In 1999, aerosols published the high culling rate of chickens with mild respiratory symptoms in the Netherlands They also found that there were large fibrous clot and foam exudation on the abdominal sacs of these chickens, and occasionally lung lesions The authors suggest that climate change and respiratory viruses may cause the health of chickens to decline, and then secondary or infection Or infection exists all over the world (Chin et al., 1997) (5) chicken infectious anemia (CIA) Bulow et al (1997) pointed out that CIA is widespread in chicken flocks, which causes immunosuppression and is susceptible to other pathogens CIAV was first isolated in Japan in 1979 (Yuasa et al., 1997) Engstrom of Sweden won the Bart RISPENS award in 1989, and his research topic is blue wing disease (Engstrom, 1988) It is pointed out that the blue wing disease is caused by the mixed infection of reovirus and CIAV In 1991, the winner was Dr Goryo of Japan His research topic was about the pathological changes caused by CIAV in bone marrow, lymphoid tissue and liver (6) avian leukosis virus type J (ALV-J) ALV-J subtype appeared in the past 10 years, which has become a major obstacle for broiler production in many countries The chickens infected with ALV-J developed myeloid leukemia, and the eggs of the diseased chickens became smaller A study by the food inspection agency of Canada collected eggs from chickens with myeloid leukemia and found that the proportion of vertical transmission of the virus in small eggs was higher than that in large eggs 2 The role of chicken manure fermentation in the control of poultry diseases the biosafety measures implemented by the poultry industry are usually to find ways to exclude pathogenic microorganisms from the chicken house However, chicken manure containing pathogenic microorganisms is often stacked or scattered on the ground near the chicken house Benton et al (1967) have proved that IBDV can still be detected after 52 days from chicken manure contaminated with IBDV chicken house CIAV also has a strong ability to survive in the environment, and it has been reported that it can be hidden in chicken manure (hope, 1992) Therefore, it is necessary to study the survival of these pathogenic microorganisms in the process of chicken manure fermentation The spread of chicken manure and other livestock manure in the soil may be an important factor in the spread of chicken disease in chicken flocks Swedish studies have shown that Salmonella typhi can be isolated from soil 8 months after application of manure (thunegard, 1975) Other studies have shown that Salmonella survives for a long time in ponds and in dry or mud like wet manure (Morse et al., 1974) Flies, mice, and birds can take Salmonella back to the henhouse from these contaminated soil and ponds (Henzler et al., 1992) Chicken manure management should be an important part of the Salmonella control program, but its importance is often overstated The fermentation of chicken manure and animal waste is an effective way to eliminate Salmonella and other pathogens In the fermentation process, the generation of heat is the most important sterilization factor Ammonia and other antimicrobial products may also play a role Historically, animal manure and straw have been mixed and piled together, and then scattered in the fields for fertilizer in a few months This method can produce heat, but the surface of the pile may not reach enough temperature to kill the pathogen The manure pile usually needs to be turned over to ventilate and promote the heat production of various parts But this method is easy to pollute tools and spread germs Another method is static accumulation plus passive ventilation fermentation, which is to set up a vent pipe inside the accumulation In this system, air flows automatically through a vent pipe (Mathur et al., 1986) As part of the disinfection of chicken farms, it may be necessary to destroy or reduce the flocks and remove the pathogens from chicken manure and other wastes when the flocks are infected with severe infectious diseases or zoonoses affecting public health The "static stack plus passive ventilation system" can work at this time It can be operated in a chicken house without complicated equipment In order to kill Salmonella and other pathogens, the fermentation temperature should be at least 55 ℃ and kept for 3 days (hussong et al., 1985) If the pile is not well ventilated, the ideal temperature may only be reached in the middle of the pile, but not in the bottom and surface The dry matter used for fermentation in the study is sawdust bedding in the chicken house, in which Salmonella typhi and sphagnum are the pollutants These dry materials are mixed with sufficient water to make the cushion material wet, and then it is piled into trapezoid shape with a volume of about 1.3m3 The fermentation pile is built around 2.6-meter-long ABS plastic pipes Each pipe has two rows of holes with a diameter of 1.2 cm and a distance of 12.7 cm In some test groups, 50.8 mm thick polystyrene board was placed under the pile to provide insulation, and its R value was 10 (calfort200) In another experiment, the waste was placed in a fabric bag used as an evaporation barrier material in the North American construction industry At the end of the bag, several pipes were stretched out to ventilate, and the bag was covered with sawdust or other edge materials, so that it could reach and maintain the required temperature Salmonella can also be isolated from the surface of fermentation pile without insulation One pile was isolated even after 152 days The fermentation pile wrapped with sawdust can kill Salmonella in 10 days (Spencer et al., 1997) After an epidemic of infectious diseases, the chicken farm should reduce the population as soon as possible, dispose chicken manure and waste materials safely, clean and disinfect them One way is to wash the chicken house with water and then ferment the wet bedding When the fermentation pile is stacked at or above 55 ℃ for 3 days, it can be moved to a convenient place to complete fermentation again Chicken manure can also be fermented together with other chicken farm wastes to produce useful soil modifications without pathogens (roviv et al., 1999) China feed industry information network nza (author:)