Browsing by Author "Gennari, S. M."

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    Effects of high temperature and disinfectants on the viability of Sarcocystis neurona sporocysts
    Dubey, Jitender P.; Saville, W. J. A.; Sreekumar, C.; Shen, S. K.; Lindsay, David S.; Pena, H. F. J.; Vianna, M. C. B.; Gennari, S. M.; Reed, S. M. (American Society of Parasitology, 2002-12)
    The effect of moist heat and several disinfectants on Sarcocystis neurona sporocysts was investigated. Sporocysts (4 million) were suspended in water and heated to 50, 55, 60, 65, and 70 C for various times and were then bioassayed in interferon gamma gene knockout (KO) mice. Sporocysts heated to 50 C for 60 min and 55 C for 5 min were infective to KO mice, whereas sporocysts heated to 55 C for 15 min and 60 C or more for I min were rendered noninfective to mice. Treatment with bleach (10, 20, and 100%), 2% chlorhexidine, 1% betadine, 5% o-benzyl-p-chlorophenol, 12.56% phenol, 6% benzyl ammonium chloride, and 10% formalin was not effective in killing sporocysts. Treatment with undiluted ammonium hydroxide (29.5% ammonia) for 1 hr killed sporocysts, but treatment with a 10-fold dilution (2.95% ammonia) for 6 hr did not kill sporocysts. These data indicate that heat treatment is the most effective means of killing S. neurona sporocysts in the horse feed or in the environment.
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    Experimentally Induced Clinical Cystoisospora canis Coccidiosis in Dogs with Prior Natural Patent Cystoisospora ohioensis-like or C. canis Infections
    Houk, Alice E.; O'Connor, T.; Pena, H. F. J.; Gennari, S. M.; Zajac, Anne M.; Lindsay, David S. (American Society of Parasitology, 2013-10)
    Diarrhea caused by intestinal coccidia (Cystoisospora species) is a common problem in pet dogs and in dogs in animal shelters. Cystoisospora canis has the largest oocysts of the 4 named species of coccidia infecting dogs. The present study examined an isolate of C. canis obtained from a dog from Sa o Paulo, SP, Brazil. Oocysts sporulated within 2 days at room temperature, and 20 sporulated oocysts were measured at 37.6 by 28.6 lm (range 35-42 by 26-31 lm). Most sporulated oocysts contained 2 sporocysts, each with 4 sporozoites, although a few (, 1%) were Caryospora-like and contained 1 sporocyst with 8 sporozoites. Two experiments using a total of 11 female 6-wk-old beagles were conducted to determine the pathogenicity of oral infection with 5 3 10 4 sporulated oocysts of this isolate of C. canis. Five of the 11 dogs had natural infections with Cystoisospora ohioensis-like (n 4) or C. canis (n 1) species prior to the predicted patent period of 9-10 days. Ten of the dogs developed diarrhea with occasional blood, and 3 dogs were affected to the extent that clinical treatment for coccidiosis using sulfadimethoxine was recommended. Dog CRU had a natural C. canis infection and did not develop clinical disease after oral infection with C. canis oocysts. This dog had a prepatent period of 9 days and a patent period of 3 days, corresponding to experimental infection with the new isolate of C. canis. It excreted fewer C. canis oocysts than did the other dogs. The 4 dogs with natural C. ohioensis-like infection all developed clinical disease, and 1 required treatment. The prepatent period was 9-10 days, and the patent period was 10-11 days in these dogs. All 6 dogs not naturally infected with Cystoisospora developed clinical disease, and 2 required treatment. The prepatent period was 9-10 days, and the patent period was 8-12 days. The present study confirms that C. canis is a primary pathogen for young dogs. It demonstrates that prior infection with C. canis but not C. ohioensis-like coccidia confers some resistance to clinical disases and a decrease in oocyst production in dogs challenged with C. canis.
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    Isolates of Sarcocystis falcatula-like organisms from South American opossums Didelphis marsupialis and Didelphis albiventris from Sao Paulo, Brazil
    Dubey, Jitender P.; Lindsay, David S.; Rosenthal, B. M.; Kerber, C. E.; Kasai, N.; Pena, H. F. J.; Kwok, O. C. H.; Shen, S. K.; Gennari, S. M. (American Society of Parasitology, 2001-12)
    Isolates of Sarcocystis falcatula-like organisms from South American opossums were characterized based on biological and morphological criteria. Sporocysts from intestinal scrapings of 1 Didelphis marsupialis and 8 Didelphis albiventris from Sao Paulo, Brazil. were fed to captive budgerigars (Melopsittacus undulants). Budgerigars fed sporocysts from all 9 isolates became ill and S. falcatula-like schizonts were identified in sections of their lungs by immunohistochemical staining. Sarcocystis falcatula-like organisms were cultured from lungs of budgerigars fed sporocysts from D. marsupialis and from lungs of budgerigars fed sporocysts from 3 of 8 D. albiventris. The 33/54 locus amplified by polymerase chain reaction from culture-derived merozoites contained both a HinfI endonuclease recognition site previously suggested to diagnose S. falcatula and a DraI site thought to diagnosed S. neurona. Development of the isolate from D. marsupialis was studied in cell cultured its schizonts divided by endopolygeny, leaving a residual body. Morphological and genetic variation differentiated this Sarcocystis isolate originating in D. marsupialis from the Cornell 1 isolate of S. falcatula. This is the first report of a S. falcatula infection in the South American opossum. D. marsupialis.
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    Prevalence of antibodies to Neospora caninum and Sarcocystis neurona in sera of domestic cats from Brazil
    Dubey, Jitender P.; Lindsay, David S.; Romand, D. H. S.; Thulliez, P.; Kwok, O. C. H.; Silva, J. C. R.; Oliveira-Camargo, M. C.; Gennari, S. M. (American Society of Parasitology, 2002-12)
    Antibodies to Neospora caninum and Sarcocystis neurona were determined in serum samples of 502 domestic cats from Brazil using direct agglutination tests with the respective antigens. Antibodies to S. neurona were not found in 1:50 dilution of any serum in the S. neurona agglutination test, suggesting that domestic cats from Sao Paulo city were not exposed to S. neurona sporocysts from opossums. Antibodies to N. caninum were found in 60 (11.9%) of 502 cats with titers of 1:40 in 36 cats, 1:80 in 18 cats, 1:160 in 5 cats, and 1:800 in 1 cat using the Neospora agglutination test (NAT). Antibodies to N. caninum were confirmed by Western blotting in the sera of 10 cats with NAT titers of 1:80 to 1:800; this finding suggests that at least 10 cats had N. caninum-specific antibodies confirmed by 2 tests. This is the first documentation of natural exposure of cats to N. caninum.
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    Prevalence of Antibodies to Trypanosoma cruzi, Leishmania infantum, Encephalitozoon cuniculi, Sarcocystis neurona, and Neospora caninum in Capybara, Hydrochoerus hydrochaeris, from São Paulo State, Brazil
    Valadas, S.; Gennari, S. M.; Yai, L. E. O.; Rosypal, A. C.; Lindsay, David S. (American Society of Parasitology, 2010-06)
    Little is known about the importance of capybara. Hydrochoerus hydrochaeris, as reservoirs for parasites of zoonotic or veterinary importance. Sera from 63 capybaras, from 6 counties in the state of Sao Paulo, Brazil, were examined for antibodies to Trypanosoma cruel, Leishmania infantum, Encephalitozoon cuniculi. Sarcacystis neurona, and Neospora caninum using an indirect immunofluorescent antibody test. Five (8%) of the 63 capybaras had antibodies to T cruzi epimastigotes. None of the samples from capybara reacted positively with L. infantum promastigotes or with spores of E. cuniculi. Two (3%) of the serum samples were positive for antibodies to S. neurona merozoites, and 2 (3%) of the serum samples were positive for antibodies to N. caninum tachyzoites. A serum sample from 1 capybara was positive for antibodies to both T cruzi and N. caninum. None of the remaining 62 samples reacted with more than 1 parasite.
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    Serological Survey for Antibodies to Encephalitozoon cuniculi in Ownerless Dogs From Urban Areas of Brazil and Colombia
    Lindsay, David S.; Goodwin, David G.; Zajac, Anne M.; Cortes-Vecino, J. A.; Gennari, S. M.; Rosypal, A. C.; Dubey, Jitender P. (American Society of Parasitology, 2009-06)
    There are 3 strains of Encephalitozoon cuniculi that occur in mammals. Strain III is associated with clinical disease in dogs, although some can be asymptomatic carriers and excrete spores in their urine. Several cases of human E. cuniculi infection caused by strain III have been observed in immunocompromised patients, indicating that E. cuniculi should be considered a zoonotic agent. Encephalitozoon cuniculi can cause fatal disease in maternally-infected or young dogs. Clinical signs in these animals included blindness, encephalitis, retarded growth rate, and nephritis. Encephalitozoon cuniculi has also been associated with primary renal failure in adult dogs. The present study used the direct agglutination test (DAT, cut-off 1:50) and the indirect fluorescent antibody test (IFAT, cut-off 1:10) to examine the prevalence of antibodies to E. cuniculi in dogs from Brazil and Colombia. Using the DAG, 31 (27.4%) of 113 dogs from Brazil and 47 (18.5%) of 254 dogs from Colombia were seropositive. Nine (14.3%) of 63 dogs from Brazil and IS (35.3%) of the 51 dogs from Colombia were seropositive by indirect immunofluorescent antibody test. These results indicate that dogs from Brazil and Colombia are exposed to E. cuniculi.