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131.
Dubey JP Lindsay DS Saville WJ Reed SM Granstrom DE Speer CA 《Veterinary parasitology》2001,95(2-4):89-131
Equine protozoal myeloencephalitis (EPM) is a serious neurological disease of horses in the Americas. The protozoan most commonly associated with EPM is Sarcocystis neurona. The complete life cycle of S. neurona is unknown, including its natural intermediate host that harbors its sarcocyst. Opossums (Didelphis virginiana, Didelphis albiventris) are its definitive hosts. Horses are considered its aberrant hosts because only schizonts and merozoites (no sarcocysts) are found in horses. EPM-like disease occurs in a variety of mammals including cats, mink, raccoons, skunks, Pacific harbor seals, ponies, and Southern sea otters. Cats can act as an experimental intermediate host harboring the sarcocyst stage after ingesting sporocysts. This paper reviews information on the history, structure, life cycle, biology, pathogenesis, induction of disease in animals, clinical signs, diagnosis, pathology, epidemiology, and treatment of EPM caused by S. neurona. 相似文献
132.
Dubey JP Black SS Rickard LG Rosenthal BM Lindsay DS Shen SK Kwok OC Hurst G Rashmir-Raven A 《Veterinary parasitology》2001,95(2-4):283-293
Sarcocystis species sporocysts were found in intestinal scrapings from 24 of 72 opossums (Didelphis virginiana) from rural Mississippi. The number of sporocysts in each opossum varied from a few ( < 100000) to 187 million. Sporocysts from 24 opossums were bioassayed for Sarcocystis neurona infections by feeding to gamma-interferon knockout (KO) mice. S. neurona was detected in the brains of KO mice fed sporocysts from 19 opossums by immunohistochemical staining with anti-S. neurona specific polyclonal rabbit serum, and by in vitro culture from the brains of KO mice fed sporocysts. The isolates of S. neurona from opossums were designated SN16-OP to SN34-OP. Merozoites from 17 of 19 isolates tested at the 25/396 locus were identical to previously described S. neurona isolates from horses. The high prevalence of S. neurona sparocysts in D. virginiana suggests that this opossum constitutes an ample reservoir of infection in the southern United States. 相似文献
133.
Equine protozoal myeloencephalitis (EPM) is the most important protozoal disease of horses in the United States. Some horse owners and equine clinicians believe that horses which are on daily pyrantel tartrate at 2.64mg/kg for helminth prophylaxis are less likely to develop EPM. The present study examined the efficacy of pyrantel tartrate in preventing clinical disease in gamma-interferon gene knockout (BALB/c-Ifng(tm1ts)) mice. No activity was seen against sporocyst-induced Sarcocystis neurona infections in mice treated prophylacticly with 4-5mg pyrantel tartrate per mouse per day in the drinking water. 相似文献
134.
Sarcocystis neurona associated granulomatous encephalitis was found in 2 of 84 adult raccoons. Both raccoons also had an extensive nonsuppurative myocarditis and one had S. neurona schizonts and merozoites in the myocardium. Only the asexual stages (schizonts and merozoites) of S. neurona are found in tissues of naturally infected animals (horse, mink, raccoons, cats, skunk, pony, seals, sea otters) and since these have not been reported outside the central nervous system, the presence of concurrent myocarditis in raccoons with the presence of S. neurona in the current study is of interest. Pathologists should consider the possible association of S. neurona with myocardial inflammation in other S. neurona susceptible animals. 相似文献
135.
Gamma interferon knockout (KO) mice (n=74) were fed a lethal dose of approximately 1000 sporocysts of the SN15-OP isolate of Sarcocystis neurona. Groups of mice were given pelleted rodent feed containing 50ppm of diclazuril at different times before and after feeding sporocysts. All mice were examined at necropsy and their tissues were examined immunohistochemically for S. neurona infection. Twenty mice were fed sporocysts and given diclazuril starting 5 days before feeding sporocysts and continuing 30-39 days post-infection (p.i.). One mouse died of causes unrelated to S. neurona with no demonstrable parasites; the remaining 19 mice remained clinically normal and S. neurona organisms were not found in their tissues. Sarcocystis neurona organisms were not demonstrable by bioassay of the brains of these 19 mice in uninfected KO mice. Sarcocystis neurona organisms were not found in tissues of five mice treated with diclazuril, starting 7 days after feeding sporocysts and continuing up to 39 days p.i. Therapy was less efficient when diclazuril was given 10 days p.i. Sarcocystis neurona organisms were found in two of 19 mice treated with diclazuril starting 10 days after feeding sporocysts, in two of five mice starting therapy 12 days p.i., and in 10 of 10 mice when treatment was delayed until 15 days p.i. All 15 mice fed S. neurona, but not given diclazuril, developed neural sarcocystosis and were euthanized 22-30 days after feeding sporocysts. Six mice not fed S. neurona, but given diclazuril for 44 days, remained clinically normal. Results indicate that diclazuril can kill the early stages of S. neurona. 相似文献
136.
Antibodies to Neospora caninum were assayed in sera of 222 female water buffaloes from Ribeira Valley of S?o Paulo State, Brazil, using an indirect fluorescent antibody test (IFAT) and Neospora agglutination test (NAT). IFAT antibodies were found in 64% of buffaloes with titers of 1:25 (42 buffaloes), 1:50 (53 buffaloes), 1:100 (31 buffaloes), 1:200 (10 buffaloes), 1:400 (3 buffaloes), or > or =1:800 (3 buffaloes). NAT antibodies were found in 53% of buffaloes; in titers of 1:40 in 52 buffaloes, 1:80 in 27 buffaloes, 1:160 in 21 buffaloes, and > or =1:320 in 17 buffaloes. Results indicate a high prevalence of N. caninum exposure in water buffaloes in Brazil and warrant an investigation of the role of N. caninum as an abortifacient in water buffaloes. 相似文献
137.
Sera from 456 wild rabbits (Oryctolagus cuniculus) collected between 1992 and 2003 from five geographical regions of Spain were examined for antibodies to Toxoplasma gondii by the modified agglutination test. Antibodies to T. gondii were found in 65 (14.2%) wild rabbits. Prevalence of infection was significantly higher in samples collected from wild rabbits from Catalonia, northeast Spain (53.8%), where rabbits lived in forest, compared to other areas (Huelva and Cádiz, Andalucía, south Spain; Toledo, Castilla-La Mancha, central Spain; and Zaragoza, Aragón, northeast Spain) with more dry conditions, where prevalence ranged from 6.1 to 14.6%. No differences were observed on prevalence and age (young animals <7 months of age compared to older animals), sex, date of samples collection or season of samples collection. The results indicate that prevalence of T. gondii in some areas of Spain is high, and this finding could have environmental and/or public health implications if wild rabbits are to be used as a source of food. 相似文献
138.
Rodrigues AA Gennari SM Aguiar DM Sreekumar C Hill DE Miska KB Vianna MC Dubey JP 《Veterinary parasitology》2004,124(3-4):139-150
Attempts were made to isolate Neospora caninum from naturally infected water buffaloes (Bubalus bubalis) from Brazil. Brains from six buffaloes with indirect fluorescent antibodies (>1:100) to N. caninum were used to isolate the parasite by bioassay in dogs and gerbils followed by in vitro culture. Shedding of Neospora-like oocysts was noticed in dogs fed brains from three buffaloes (isolate designation NcBrBuf-1, 2 and 4). Two more isolates (NcBrBuf-3 and 5) were obtained by in vitro culture of the brains of gerbils previously infected with brains of two other buffaloes. The identity of the isolates was confirmed by biological and molecular methods. The isolates were found to be non-pathogenic to gerbils. All five isolates amplified the gene 5 amplicons using Neospora-specific PCR assay. The sequences of gene 5 fragments and the common toxoplasmatiid ITS-1 fragments were analyzed. The dynamics of oocyst production in the dogs indicate that water buffaloes are natural intermediate hosts for N. caninum. This is the first report of isolation of N. caninum from water buffaloes. 相似文献
139.
Prevalence of antibodies to Neospora caninum was determined in a cross-sectional consensus survey of 1029 bovines in a dairy herd with endemic Neospora-induced abortion. Sera were screened by indirect fluorescent antibody test (IFAT). The prevalence of N. caninum antibody in the IFAT was 17.9% in 107 neonates, 26.2% in 233 yearling heifers and steers, 39.07% in 218 mature heifers, and 26.9% in 465 milking cows. Serologic reactivity was associated with production grouping on the farm with the greatest risk of serologic reactivity appearing in the yearling and mature heifers. There was an increasing risk of serologic reactivity with increasing age only in the parity one and greater animals in the herd. Castrated males were at half the risk of similarly aged females of possessing antibodies to N. caninum. There was no clear relationship between the serologic status of dams and offspring. 相似文献
140.
Toxoplasma gondii tachyzoites were seen in the placenta of a late-term aborted Greenland muskox (Ovibos moschatus wardi) fetus in a captive herd at the San Francisco Zoo. The organism stained with anti-T. gondii polyclonal rabbit serum but not with anti-Neospora caninum serum. The dam had a Toxoplasma titer of > or =1:3,200 at the time of abortion and in each of the previous 3 yr (modified agglutination test). The muskox is a new host record for T. gondii. 相似文献