猪的体内寄生虫

猪的生产性能受到体内寄生虫的影响,大多数寄生虫主要生存在幼龄、生长期的猪。体内寄生虫能导致猪死亡,但是,食欲不振、日增重下降、饲料转化效率差和容易感染其它病原体是寄生虫病引发的较常见症状。生产性能影响大多因所在地理区域、猪舍类型、管理方式、营养水平、     

Seasonality of sarcoptic mange in pigs in South Australia

Retrospective analysis of records, from July 1987 to June 1991, of 1140 inspections of slaughtered pigs from 154 swine herds in the Pig Health Monitoring Scheme of South Australia was conducted to evaluate patterns of variation in the prevalence and severity of skin lesions typical of sarcoptic mange. An increase in the severity of sarcoptic mange in winter and spring was observed. There was a substantial reduction in the severity of mange over the period of monitoring. These observations support the role of monitoring at slaughter in the management of endemic disease. They provide some basis for refining control programs for mange to improve cost-effectiveness.     

The trichostrongyloid parasites of sheep in South Australia and their regional distribution

Summary. The species of trichostrongyloid nematodes present in 376 sheep from different agricultural regions of the state of South Australia were determined.
Parasites encountered in the abomasum were Teladorsagia circumcincta, T. trifurcata, T. davtiani, Camelostrongylus mentulatus, Haemonchus contortus and Trichostrongylus axel. T. circumcincta was the species most commonly encountered, but C. mentulatus was widespread in arid areas. H. contortus was present in a small number of sheep only, mainly in southern areas.
In the small intestine, Trichostrongylus vitrinus predominated in the wetter, southern districts, and T. rugatus in dry, northern areas. T. colubriformis was common, but was rarely dominant. T. probolurus was found in one sheep. Nematodirus filicollis was restricted to wetter, southern areas, while N. spathiger and N. abnormalis were widespread and predominated in dry areas. N. helvetianus was found once. Cooperia species were uncommon; species encountered were C. oncophora, C. surnabada and C. pectinata.
Thanks are due to P. M. Bonnin, E. Moore, S. M. Fitzsimons, F. M. and R. R. Martin and M. G. O'Callaghan for excellent technical assistance, and to members of the South Australian Department of Agriculture, particularly the staff of the Northern Region, for collecting material or helping with the collection.     

Internal parasites of free-ranging guanacos from Patagonia

In the winter of 2000, a greater than 80% reduction in the guanaco population located in Cabo Dos Bahi;as Wildlife Reserve, Chubut, Argentina, was evident due to massive mortality attributed to starvation. Twelve guanacos were necropsied and samples were analyzed at the Parasitology Laboratory of Facultad de Ciencias Veterinarias, Universidad Nacional del Litoral. Fecal analysis revealed developmental stages of Nematodirus sp., Marshallagia sp., Trichuris sp. and Eimeria spp. Histopathological analysis showed the presence of Sarcocystis sp. in muscle and fascia cysts. Other parasites recovered included Dictyocaulus filaria, Trichuris tenuis and Moniezia expansa. Of these, D. filaria and M. expansa possibly reflect interactions with domestic sheep. This is the first time that T. tenuis has been reported in guanacos.     

Internal parasites of horses on mixed grassveld and bushveld in Transvaal, Republic of South Africa

Between 1980 and 1982, the gastrointestinal tracts of 17 horses which had been grazing on mixed grassveld at Potchefstroom and bushveld at Onderstepoort in the province of Transvaal, Republic of South Africa, were examined at necropsy and processed for parasite recovery. The large strongyles and their prevalences were as follows: Strongylus vulgaris and associated lesions (88-94%), Strongylus edentatus (24%), Strongylus equinus (30%), Triodontophorus nipponicus (35%) and Craterostomum acuticaudatum (18%). The seven most prevalent and abundant cyathostomes collected were Cylicostephanus longibursatus, Cylicostephanus goldi, Cylicostephanus calicatus, Cylicocyclus nassatus, Cyathostomum catinatum, Cylicostephanus minutus and Cyathostomum coronatum. Gasterophilus intestinalis was the most prevalent and abundant botfly larva recovered. Most of the cyathostome larvae and adults were present during all seasons except winter. The distribution of cyathostome species in the large intestine of the host is discussed.     

Helminth parasites of dogs from two resource-limited communities in South Africa

Biological samples were collected from dogs in resource-limited communities in the North-West and Gauteng Provinces of South Africa to assess the prevalence of helminth parasitism. These samples included adhesive tape peri-anal skin swabs and fresh faecal samples for helminth examination, and thick and thin blood films (smears) and whole-blood samples in anticoagulant for examination of filarial nematode microfilariae and haemoprotozoa. The eggs of Ancylostoma caninum, Toxocara canis, Toxascaris leonina, Dipylidium caninum and taeniids were identified. None of the blood samples and smears tested positive for microfilariae of Dirofilaria immitis or Dipetalonema spp. or for haemoprotozoa. The adhesive tape swabs were negative for cestode eggs and segments. Most of the helminth parasites identified in this study are zoonotic and consequently are regarded as a public health hazard.     

Enzootic pneumonia of pigs in South Australia — factors relating to incidence of disease

Environmental and management conditions of 15 herds with a high-prevalence (greater than 70%) of enzootic pneumonia of pigs at slaughter were compared with 16 herds with a low-prevalence (less than 30%) to determine factors commonly predisposing pigs to enzootic pneumonia in South Australia. Comparisons were made of herds having greater than 100 sows (fully intensive units) and also small herds having 20 to 70 sows (sideline units). Half the herds were visited in summer and half in winter to detect seasonal factors. In small herds, factors commonly found associated with a high prevalence of enzootic pneumonia were larger numbers of pigs per shed section (p less than 0.001), larger group sizes (p less than 0.01) and draughty farrowing and weaner accommodation (p less than 0.01). In large herds, factors associated with a high prevalence were higher pen stocking rate (p less than 0.05) and airspace stocking rate (p greater than 0.05), and a trend toward higher atmospheric ammonia levels in summer (p less than 0.1).     

Internal parasites of Washington cattle.

The occurrence of internal parasites in Washinton cattle was estimated. During the survey period in 1972 and 1973, more than 3,700 fecal samples from 29 herds and 4 feedlots, and viscera from 55 cattle were examined. The percentage of fecal samples with parasite eggs or oocysts from herds was as follows: oocysts, 77%; "strongyline" eggs, 44%; Nematodirus eggs, 3%; Moniezia eggs, 3%; Fasciola eggs, 2%; Trichuris eggs, 2%; and Dictyocaulus larvae, 1%. The fecal samples from feedlots contained principally strongyline eggs which varied markedly in numbers among groups of cattle in the lots. The predominant parasite in viscera was Ostertagia spp, which was recovered from all of the cattle examined. Other parasites identified in the survey were found less frequently in these examinations. Cattle in dairy and beef operations utilizing irrigated pastures were particularly prone to Fasciola infections, and more strongyline eggs were observed there than in fecal samples from other management systems. Seasonal fluctuations in numbers of strongyline and Fasciola eggs were pronounced.     

Nose-rings and transmission of helminth parasites in outdoor pigs

Five growing pigs experimentally infected with low doses of Oesophagostomum dentatum, Ascaris suum, and Trichuris suis were turned out with 5 helminth-na?ve pigs on each of 3 pastures in June 1996 (Group 1). On one pasture all pigs received nose-rings. After slaughter of Group 1 in October, pasture infectivity was monitored using helminth-na?ve, unringed tracer pigs. In 1997, helminth-na?ve young pigs were turned out on the contaminated pastures in May (Group 2) and again in August (Group 3). Again all pigs on one pasture received nose-rings. All pigs and pastures were followed parasitologically and reduction in grass cover was monitored. Based on the acquisition of infection by the na?ve pigs in Group 1, the estimated minimal embryonation times for eggs deposited on pasture were 23-25 days for O. dentatum, 5-6 weeks for A. suum and 9-10 weeks for T. suis. Results from tracer pigs and grass/soil samples indicated that pasture infectivity was light both years. Free-living stages of O. dentatum did not survive the winter. The nose-rings reduced rooting considerably, resulting in three-fold more grass cover on the nose-ring pasture compared to the control pastures by the end of the experiment. Nevertheless, the nose-rings did not significantly influence parasite transmission.     

Actinobacillus suis infection in pigs in Australia

This is the first report of the isolation of Actinobacillus suis in association with significant disease among preweaned pigs in Australia. Sudden deaths occurred in preweaned piglets at one facility and enlarged joints, particularly the stifles and tarsi, occurred at another. Isolates with the biochemical phenotype and apx genotype profile of A suis were cultured from affected piglets. Both facilities were of high health status and one had undergone a recent depopulation, disinfection and sow repopulation process. Reviewing initial reports of A suis disease overseas, it is apparent that outbreaks occurred sporadically in various locations, with disease occurring among the herds involved for some months only, before development of immunity. A suis disease is now considered an emerging disease on high health status farms.