Browsing by Author "Pena, H. F. J."

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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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    The South American opossum, Didelphis marsupialis, from Brazil as another definitive host for Sarcocystis speeri Dubey and Lindsay, 1999
    Dubey, Jitender P.; Kerber, C. E.; Lindsay, David S.; Kasai, N.; Pena, H. F. J. (Cambridge University Press, 2000-12)
    The North American opossum, Didelphis virginiana, is a definitive host for at least 3 species of Sarcocystis: S. falcatula Stiles 1983, S. neurona Dubey, Davis, Speer, Bowman, de Lahunta, Granstrom, Topper, Hamir, Cummings, Suter 1991, and S. speeri Dubey and Lindsay 1999. In order to identify species of Sarcocystis in the South American opossum, D. marsupialis, Sarcocystis sporocysts from the intestines of a naturally infected opossum (D. marsupialis) from Brazil were fed to 4 gamma-interferon knockout (KO) mice, a nude mouse, and 2 budgerigars (Melopsittacus undulatus). All 4 KO mice became ill and 1 died 42 days post-feeding (p.f.) of sporocysts, 1 was killed 44 days p.f. because of neurological signs, and 2 were killed 52 and 53 days p.f, because of abnormal gaits. Numerous sarcocysts were seen in the skeletal muscles of all 4 KO mice and they were structurally identical to S. speeri seen in KO mice fed sporocysts from D. virginiana from the United States and D. albiventris from Argentina. The nude mouse was killed 41 days p.f. because it appeared weak; schizonts were seen in sections of its liver and sarcocysts were seen in sections of skeletal muscles. Sarcocystis speeri was cultured in bovine turbinate cells inoculated with liver homogenate from this mouse. Sarcocystis neurona was not demonstrable in tissues of mice. The tale budgerigars remained asymptomatic and S. falcatula was not found in their tissues when they were killed 29 days p.i. This is the first report of S. speeri from D. marsupialis.