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1.
Objective   To describe the structure of the Australian poultry industry and discuss the potential for highly pathogenic avian influenza (HPAI) to spread between Australian poultry farms.
Procedure   High densities of poultry farms, frequent contacts between farms by service providers, the supply of live poultry markets (LPM) and the presence of free-range duck flocks in affected regions have been identified as risk factors for the spread of HPAI between flocks in outbreaks causing the death or destruction of over 1 million poultry overseas. Data on 1,594 commercial Australian chicken meat, chicken egg, duck and turkey farms were collected by a telephone questionnaire of farm managers to assess the risk of a HPAI outbreak in Australia.
Results and Discussion   Five regions of Australia had farm densities comparable to overseas regions that experienced widespread HPAI. Common service providers routinely contacted different classes and types of farms over wide geographic areas. However, no responding farms supplied LPM and the majority of duck farms did not produce free-range ducks.
Conclusion   Outbreaks of HPAI have the potential to cause serious impacts on the Australian poultry industry. The risk posted by LPM and free-range ducks is limited, but the movement of genetic stock and common service providers could spread infection between companies, industries or geographical regions. Biosecurity measures are therefore considered critical to limit the secondary spread of infection should an outbreak occur.  相似文献   

2.
OBJECTIVE: To identify risk factors associated with the spread of low pathogenicity H7N2 avian influenza (AI) virus among commercial poultry farms in western Virginia during an outbreak in 2002. DESIGN: Case-control study. PROCEDURE: Questionnaires were used to collect information about farm characteristics, biosecurity measures, and husbandry practices on 151 infected premises (128 turkey and 23 chicken farms) and 199 noninfected premises (167 turkey and 32 chicken farms). RESULTS: The most significant risk factor for AI infection was disposal of dead birds by rendering (odds ratio [OR], 73). In addition, age > or = 10 weeks (OR for birds aged 10 to 19 weeks, 4.9; OR for birds aged > or = 20 weeks, 4.3) was a significant risk factor regardless of poultry species involved. Other significant risk factors included use of nonfamily caretakers and the presence of mammalian wildlife on the farm. Factors that were not significantly associated with infection included use of various routine biosecurity measures, food and litter sources, types of domestic animals on the premises, and presence of wild birds on the premises. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that an important factor contributing to rapid early spread of AI virus infection among commercial poultry farms during this outbreak was disposal of dead birds via rendering off-farm. Because of the highly infectious nature of AI virus and the devastating economic impact of outbreaks, poultry farmers should consider carcass disposal techniques that do not require off-farm movement, such as burial, composting, or incineration.  相似文献   

3.
OBJECTIVE: To investigate an outbreak of sudden severe mortality in farmed abalone from coastal Victoria. RESULTS: The outbreaks occurred almost simultaneously in three farms following abalone movements from the wild and between farms. The initial on farm investigation identified a number of features that when considered together were highly suggestive of an infectious aetiology. In many cases, dead abalone had no significant gross lesions. Others had swollen mouths and some had prolapse and eversion of the radula. Histologically, the lesions centred on the nerves innervating the labial apparatus, primarily the cerebral and buccal ganglia, cerebral commissure and peripheral nerve branches arising from these. Nervous tissue necrosis and haemocyte infiltration were the dominant lesions seen microscopically in affected nerves. CONCLUSIONS: A recent outbreak of mortality in Australian abalone was associated with neurotropic lesions, which have not previously been described in this country. The on farm and between farm pattern of spread of the outbreak, a history of abalone movements linking farms, clinical observation of moribund and dead abalone were all highly suggestive of a virulent infectious agent.  相似文献   

4.
为了解贵州省H7亚型禽流感感染情况,采用HI试验对全省9个地区家禽血清样本进行血清抗体检测,PT-PCR方法对家禽咽-肛拭子、养禽场环境样本和野鸟粪便进行病原核酸检测。结果显示:在1570份家禽血清样本中,H7亚型禽流感血清抗体阳性率为0.45%(7/1570);在350份家禽咽-肛拭子和310份养殖场环境样本中,均未检测出H7亚型禽流感病毒核酸;在160份野鸟粪便中,有1份为H7亚型禽流感病毒核酸阳性,阳性率为0.63%(1/160)。试验提示,在贵州省养禽场中不存在H7亚型禽流感感染,但迁徙野禽中可能存在H7亚型禽流感隐性感染,应当引起重视。  相似文献   

5.
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6.
Clinical observations on an outbreak of strangles   总被引：1，自引：0，他引：1       下载免费PDF全文
An outbreak of strangles, which occurred during the spring, summer and fall of 1980 on a Standardbred stud farm in eastern Alberta is described. The infective organism, Streptococcus equi, may have been introduced by an outside mare that was brought to the stud for breeding. All of the groups of horses on the farm were affected. For the most part, the disease was allowed to run its natural course. Only severely affected individuals were treated. During the outbreak, the foals were prophylactically treated with penicillin to prevent them from contracting the disease. Ten horses died of complications of strangles infection.  相似文献   

7.
科学疫病防控是现代化家禽养殖产业发展中一项重要和不可或缺的工作,是实现鸡养殖产业健康可持续发展的关键所在。由于农村地区的很多养殖户科学疫病防控重视程度不高,在养殖管理过程中并没有构建完善的疫病防控措施,养殖管理方案不当,鸡群处于亚健康状态,身体抵抗能力较差,一旦某些传染性疾病在养殖场中爆发流行,很容易造成严重危害,使大量鸡死亡,给养殖场带来不可挽回的经济损失。该文分析农村养鸡防疫存在的问题,论述具体的解决措施。  相似文献   

8.
In 1999-2000, Italian poultry production was disrupted by an H7N1 virus subtype epidemic of highly pathogenic avian influenza (HPAI). The objectives of the present study were to identify risk factors for infection on poultry farms located in regions that had the highest number of outbreaks (Veneto and Lombardia) and the impact of pre-emptive culling as a complementary measure for eradicating infection. A Cox regression model that included spatial factors, such as the G index, was used. The results confirmed the relationship between risk of infection and poultry species, production type and size of farms. The effectiveness of pre-emptive culling was confirmed. An increased risk of infection was observed for poultry farms located near an infected farm and those at altitudes less than 150m above sea level. The measures for the control and eradication of AI virus infection need to consider species differences in susceptibility, the types of production and the density of poultry farms in the affected areas.  相似文献   

9.
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10.
This study was undertaken to supply information on Aspergillus fumigatus infection of poultry in Nigeria. The disease in broiler chicks was characterized by gasping, droopiness, emaciation and heavy mortality while affected grower chickens showed emaciation, weakness, diarrhoea and 17 per cent mortality. The disease was sporadic in laying flocks. Granulomatous nodules were observed in birds that died in each outbreak. The nodules were numerous and affected mainly the lungs and thoracic air sacs in the broiler chicks while only few large nodules were observed mainly in the abdominal air sacs in the layers.  相似文献   

11.
The first outbreak of reovirus infection in broiler chickens was observed in the Sudan in the largest poultry industry of the country. The disease was characterized clinically by growth retardation, lameness, poor feathering, shank depigmentation and occasionally retraction of the head. Grossly there was enlargement of the proventriculus, atrophy of the pancreas and bone abnormalities. Histopathologic changes included hepatitis, nephritis, myocarditis, pericarditis, catarrhal enteritis, pancreatic necrosis, encephalomalacia and ricketic changes. Details were described. Reovirus was isolated from affected birds and reisolated from experimentally infected chicks. Infection was confirmed by immunoelectrophoresis and agar gel precipitation tests.  相似文献   

12.
Disease of geese caused by a new herpesvirus   总被引：3，自引：0，他引：3  
A goose flock farmed outdoors in south-eastern Queensland suffered an outbreak of peracute disease with high death rate (97%). Small button ulcers and large plaques overlying lymphocyte aggregates were present on the mucosa of the small intestine of affected birds. Small white foci of necrosis and focal haemorrhages were seen in the livers. Numerous intranuclear inclusion bodies were observed microscopically in hepatocytes and a herpesvirus which grew rapidly in chicken kidney cells was isolated from tissues. Duck virus enteritis (DVE) was suspected but DVE antiserums failed to neutralise the virus. Further serological studies with a limited range of known avian herpesviruses have failed to identify the virus. Experimental transmission resulted in high mortality in geese (100%), lower mortality in ducklings and nil mortality in chickens. Surveillance studies showed no evidence of infection in domestic and wild birds beyond the original farm and the infection appears not to have been established in the area. Wild ducks, which were frequent visitors to the farm dam, were considered the most likely source of the infection.  相似文献   

13.
An outbreak of abortions, stillbirths, mummified piglets and neonatal deaths in a pig herd in Arequipa, Peru is described. A total of 31 of 240 sows aborted between May and September 1988. When sera were examined 12 of 14 had very high titres of antibody to canicola PC125 and canicola Hond Utrecht, but there were also high titres of antibody to other leptospiral serovars. A detailed investigation was made and serovar canicola PC125 was isolated from the urine of four sows which had aborted and the kidney of one slaughter pig. Antibodies to various serovars of Leptospira were demonstrated in 11 of 17 sows which had aborted, two of six sows which had normal litters, nine of 18 boars, four of 39 slaughter pigs and four of 14 workers on the farm. The outbreak was brought under control by treatment and vaccination coupled with a thorough cleaning of the farm and control of the wild animal population. It is suggested that the infection was brought onto the farm by wild animals and that the disease is more common in Arequipa than was previously supposed.  相似文献   

14.
Several outbreaks of virulent Newcastle-disease occurred in Australia in 1998–2000. We conducted a cross-sectional survey of 753 Australian chicken farms to identify risk factors associated with the seroprevalence of chicken flocks with Newcastle-disease virus (NDV). We had a 99.7% response rate to the survey and the overall prevalence of NDV seropositive farms was 39.8%. Associations were analysed for the layer, chicken-meat and breeder production sectors in sector-specific logistic-regression models using 187, 198 and 146 farms, respectively. In the layer sector, increased risk of seroprevalence was associated with increasing age of the chickens, and decreased risk when the nearest-neighbour poultry farm was >10 km distant (odds ratio (OR) = 0.30). In the chicken-meat sector, increased risk of seroprevalence was associated with location in the Sydney basin (OR = 13.67), eastern Victoria (OR = 26.10) or western Victoria (OR = 5.43), and decreased risk when the nearest-neighbour poultry farm was greater than 0.5 km distant (OR = 0.34). In the breeder sector, increased risk of seroprevalence was associated with increasing age of the chickens, the presence of wild birds on the farm (OR = 5.28) and location in eastern Victoria (OR = 16.19). A conditional logistic-regression for 112 pairs of farms matched for age, survey region and production sector identified a distance of >1.0 km to the nearest-neighbour poultry farm (OR = 0.24) and ownership by owner 2 (OR = 0.02), owner 5 (OR = 0.11) or owner 9 (OR = 0.25) as significant in reducing the risk of NDV seroprevalence. Our survey found that high levels of biosecurity and hygiene practices had been adopted by most farms.  相似文献   

15.
A study was conducted on an outbreak of Marek's disease in a commercial poultry farm containing 8500 chickens in central Ethiopia. On repeated visits, farm and flock history was collected, sick birds were examined and clinical signs and daily mortality were recorded. A total of 80 (27 sick and 53 dead) birds 12-22 weeks old, were collected, autopsied and examined. The mortality rate was 46% for the first 14 weeks of the outbreak. Acute and chronic (classical) forms of the disease, the respective occurrence of which varied significantly (p<0.01) in young (14.6% vs 85.4%) and adults (48.7% vs 51.31%) were manifested. All the autopsied birds had gross and microscopic lesions indicative of Marek's disease in the peripheral nerve(s) and/or visceral organs. Lesions involving peripheral nerves and visceral lymphomas were recorded mainly in adults (28/35, 80%) and young birds (34/45, 75%), respectively. These differences in the two age groups were statistically significant (p<0.01). Young birds seem to be highly susceptible to the acute disease. Poor management, overstocking and lack of vaccination might have favoured the outbreak. Marek's disease causes considerable economic loss and is a major threat to poultry production in Ethiopia. This report emphasizes that Marek's disease should be considered as a disease of economic significance in chicken production in Ethiopia and warrants due attention.  相似文献   

16.
An outbreak of goose parvovirus (GPV) infection on a Swedish goose farm in the spring of 2004 increased the mortality rates from 2% in the early unaffected hatches to 90% and 99% respectively in the two hatches following virus introduction and 40% in goslings hatched later in the same breeding season. In this paper we describe the clinical observations, diagnostic procedures, and epidemiologic investigation carried out to elucidate the source of the infection. The diagnosis was confirmed by serology, virus isolation, and sequence analysis of a 493-bp-long fragment of the VP1 gene. Phylogenetically the causative virus was closely related to pathogenic GPV strains isolated in 2003 and 2004 from Poland and the United Kingdom, respectively. The Swedish isolate exhibited less homology with pathogenic strains from Hungary and Asia and with attenuated vaccine strains. The epidemiologic investigation showed that the virus was first introduced to a contract farm (farm A) and then was transferred with newly hatched goslings to the farm that had submitted the birds for necropsy (index farm). The exact time and source of the virus introduction to farm A could not be determined with absolute certainty. Possible sources of the infection included backyard goose eggs that had been delivered to farm A for subcontract incubation and hatching, wild geese that frequented the flock of breeding geese on pasture on farm A, and a clutch of Canada goose eggs (Branta canadensis) that had been produced by wild geese and was hatched in the same machine as the eggs produced by farm A.  相似文献   

17.
The integrated commercial poultry system is a highly connected network in which routine activities keep farms within a geographic area in constant contact. Consequently, biosecurity practices designed to minimize the transmission of infectious diseases between and within farms are an important component of modern flock health programs. A survey of Georgia poultry growers was conducted in order to assess the level of adoption of standard biosecurity measures by farm personnel and visitors. The results showed that compliance with recommended biosecurity practices did not significantly vary by company, farm size, or number of farms owned by the same grower. However, biosecurity was higher in the northern part of the state, where the density of farms is higher, and where there was an ongoing outbreak of infectious laryngotracheitis at the time of the study. The survey found that growers place more emphasis on biosecurity measures targeting farm visitors than those targeting farm personnel. Most growers reported that all visitors to the farm were required to wear shoe covers, although visitors were not typically required to park outside the farm entrance or to wash tires on their vehicles. No visitor type was reportedly excluded from poultry houses during grow out on all farms. The results highlight the need to evaluate the comparative efficacy of specific biosecurity measures in order to set priorities and attain feasible rates of implementation of targeted biosecurity practices.  相似文献   

18.
During the latter stages of the lethal H5N2 influenza eradication program in domestic poultry in Pennsylvania in 1983-84, surveillance of waterfowl was done to determine if these birds harbored influenza viruses that might subsequently appear in poultry. From late June to November 1984, 182 hemagglutinating viruses were isolated from 2043 wild birds, primarily ducks, in the same geographical area as the earlier lethal H5N2 avian influenza outbreak. The virus isolates from waterfowl included paramyxoviruses (PMV-1, -4, and -6) and influenza viruses of 13 antigenic combinations. There was only one H5N2 isolate from a duck. Although this virus was antigenically related to the lethal H5N2 virus, genetic and antigenic analysis indicated that it could be discriminated from the virulent family of H5N2 viruses, and it did not originate from chickens. Many of the influenza viruses obtained from wild ducks were capable of replicating in chickens after experimental inoculation but did not cause disease. These studies show that many influenza A virus strains circulating in waterfowl in the vicinity of domestic poultry in Pennsylvania did not originate from domestic poultry. These influenza viruses from wild ducks were capable of infecting poultry; however, transmission of these viruses to poultry apparently was avoided by good husbandry and control measures.  相似文献   

19.
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20.
BackgroundSince 2003, the H5 highly pathogenic avian influenza (HPAI) subtype has caused massive economic losses in the poultry industry in South Korea. The role of inland water bodies in avian influenza (AI) outbreaks has not been investigated. Identifying water bodies that facilitate risk pathways leading to the incursion of the HPAI virus (HPAIV) into poultry farms is essential for implementing specific precautionary measures to prevent viral transmission.ObjectivesThis matched case-control study (1:4) examined whether inland waters were associated with a higher risk of AI outbreaks in the neighboring poultry farms.MethodsRivers, irrigation canals, lakes, and ponds were considered inland water bodies. The cases and controls were chosen based on the matching criteria. The nearest possible farms located within a radius of 3 km of the case farms were chosen as the control farms. The poultry farms were selected randomly, and two HPAI epidemics (H5N8 [2014–2016] and H5N6 [2016–2017]) were studied. Conditional logistic regression analysis was applied.ResultsStatistical analysis revealed that inland waters near poultry farms were significant risk factors for AI outbreaks. The study speculated that freely wandering wild waterfowl and small animals contaminate areas surrounding poultry farms.ConclusionsPet birds and animals raised alongside poultry birds on farm premises may wander easily to nearby waters, potentially increasing the risk of AI infection in poultry farms. Mechanical transmission of the AI virus occurs when poultry farm workers or visitors come into contact with infected water bodies or their surroundings. To prevent AI outbreaks in the future, poultry farms should adopt strict precautions to avoid contact with nearby water bodies and their surroundings.  相似文献   

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