Resistance of calves to Cryptosporidium parvum: effects of age and previous exposure.
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Cryptosporidium parvum is a coccidian parasite that causes diarrheal disease in many vertebrate species, including young (less than or equal to 1 month old) calves. Older calves and adult cattle are resistant to infection. In this study, newborn calves were raised in isolation from C. parvum for 1 week to 3 months before experimental challenge with the parasite. Calves orally challenged with C. parvum at 1 week of age shed oocysts in their feces and had diarrhea after challenge exposure. When these calves were rechallenged at 1 and 3 months of age, they neither shed oocysts nor had diarrhea. There was no significant increase in the mean anticryptosporidium enzyme-linked immunosorbent assay serum antibody titer in these calves following any of the challenge exposures. Calves orally inoculated with C. parvum for the first time at 1 month of age shed oocysts, had diarrhea after challenge exposure, and were resistant to rechallenge at 3 months of age. These calves had a twofold increase in serum antibody titer after the first challenge and no increase after the second challenge. Calves orally inoculated with C. parvum for the first time at 3 months of age shed oocysts, and two of seven animals had diarrhea. These calves had a 10-fold increase in serum antibody to C. parvum after exposure. This study demonstrates that calves raised in isolation from C. parvum remain susceptible to challenge until at least 3 months of age. Furthermore, within this time period, initial exposure and recovery renders calves resistant to further challenge with the parasite. The data also suggest that exposure of young calves to C. parvum may inhibit the development of a serum antibody response to the parasite. (+info)
Anthelmintic treatment alters the parasite community in a wild mouse host.
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Ecological attributes of Hepatozoon lacertilis Gupta et al., 2011 susceptibility in Indian lizards, Hemidactylus flaviviridis (Gekkonidae) and Calotes versicolor (Agamidae).
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Ecological attributes of haematozoan parasites are poorly understood. In this study, we report haematozoan prevalence in two species of Indian lizards, Hemidactylus flaviviridis (Family: Gekkonidae) and Calotes versicolor (Family: Agamidae) under three macro-environmental variables: host location, weight and seasonal variations. Hemidactylus flaviviridis (n= 199) and Calotes versicolor (n= 34) were sampled from Bareilly, Chandausi and Mirzapur, Uttar Pradesh, India belonging to different weight groups [Group I (0-5 gm), Group II (5-10 gm) and Group III (10-15 gm)] and during various seasons [Summer (May-July), Rainy (August-October), Winter (November-January), Spring (February-April)] of the year. A haemogregarine, Hepatozoon Miller, 1908 was discovered from both host species. Test for identity of the parasites was conducted by feeding infected Culex quinquefasciatus (Diptera: Culicidae) on infection-free H. flaviviridis and C. versicolor and blood examinations on 22(nd) day (H. flaviviridis) and 25(th) day (C. versicolor) post feeding (pf) revealed similar haematozoan parasites and were identified as Hepatozoon lacertilis Gupta et al., 2011. Infectivity from different locations indicated a prevalence of 5.26% (Bareilly) and 16.36% (Mirzapur) in H. flaviviridis whereas infectivity was comparatively higher (19.23%) in C. versicolor. In different weight groups, Group III indicated highest infectivity in both lizards being 21.42% (C. versicolor) and 17.85% (H. flaviviridis). Parasites showed highest prevalence during spring season (H. flaviviridis : 9.52%; C. versicolor : 25%). Values of significance were determined by chi-square test to compare the prevalence within different variables (host location, weight and season). The study has importance for its contribution to the knowledge on the diversity of reptilian hosts infected by haemogregarines. It is the first record of Hepatozoon infectivity in both lizard species with respect to the three macro-environmental variables. (+info)
Differential sources of host species heterogeneity influence the transmission and control of multihost parasites.
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Cryptosporidium parvum (Apicomplexa: Cryptosporidiidae) oocyst and sporozoite antigens recognized by bovine colostral antibodies.
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Colostral whey from seven hyperimmunized and two control cows (hyperimmune bovine colostrum) was examined by Western immunoblotting for the presence of antibody against oocysts and sporozoites of Cryptosporidium parvum, using rabbit anti-bovine immunoglobulin A (IgA), IgG1, IgG2, and IgM antibodies, followed by a horseradish peroxidase goat anti-rabbit polyvalent antibody. Although considerable variation was found in binding activity between cows on different immunization protocols, IgA and IgG1 in whey recognized a greater variety of C. parvum antigens than did IgG2 and IgM. A band at 9 to 10 kilodaltons appeared unique in that it was recognized only by IgA. (+info)
Occurrence of gastrointestinal parasites in slaughter rabbits.
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Comparison of sedimentation and flotation techniques for identification of Cryptosporidium sp. oocysts in a large outbreak of human diarrhea.
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Cryptosporidiosis, previously seen mostly among immunocompromised patients, is now recognized among immunocompetent patients. During a large outbreak of cryptosporidiosis in two day-care centers, we compared two procedures for the demonstration of the organism in preserved stool specimens. Of 703 stool specimens tested by both techniques, Sheather sucrose flotation (SSF) identified 127 (18.1%) as positive for Cryptosporidium sp. oocysts. Ritchie Formalin-ethyl acetate sedimentation (F/EA) plus a modified cold Kinyoun acid-fast stain (MCK) of the sediment identified 129 (18.4%) as positive for Cryptosporidium sp. oocysts. The degree of agreement between the two tests was statistically highly significant (P less than 0.0001). A total of 161 (22.9%) were positive by one technique or the other; 95 (13.5%) were positive by both techniques. A total of 32 specimens were positive by SSF but negative by F/EA plus MCK, and 34 specimens were positive by F/EA plus MCK but negative by SSF. The discrepancies between the two techniques occurred in stool specimens that contained rare to a few oocysts. Other parasitic forms were found by both techniques. F/EA plus trichrome staining recovered 126 (17.9%) specimens with Giardia lamblia, whereas SSF recovered only 42 (6.0%) specimens with G. lamblia. No association (chi 2 = 0.02, P = 0.89) was observed between the presence of G. lamblia and Cryptosporidium sp. in these stool specimens. We concluded that F/EA plus MCK of the sediment was as effective in the concentration and identification of Cryptosporidium sp. oocysts as SSF. F/EA plus MCK may be advantageous as a single concentration method for general parasitology when Cryptosporidium sp. is also being sought. (+info)