Search

Giardia and Cryptosporidium are protozoan parasites known to cause enteric disease in terrestrial wildlife species (mammals, reptiles and birds). Few surveys for Giardia and Cryptosporidium in marine wildlife species, such as pinnipeds, have been reported. The objective of this study was to determine the prevalence and genotype of Giardia and Cryptosporidium in two species of pinnipeds, harp seal (Phoca groenlandica) and hooded seal (Cystophora cristata), from the Gulf of St. Lawrence, Canada. Faecal samples were collected from pup and adult seals and examined for the presence of cysts of Giardia and oocysts of Cryptosporidium using microscopy and immunofluorescent staining. Tissues from the small intestine of adult seals were also collected and examined for infections using the polymerase chain reaction (PCR) technique. Giardia cysts were found in the faeces of 42% (16/38) of adult harp seals, but in none of the harp seal pups (0/20). Although Giardia cysts were not detected in faeces of adult hooded seals (0/10) using microscopy, 80% tested positive for Giardia using PCR of intestinal tissue indicative of a true replicating infection. Both harp and hooded seals harboured infections with the zoonotic strain, Giardia duodenalis Assemblage A, as determined using a nested-PCR technique to amplify a small subunit ribosomal (SSU-rRNA) gene of Giardia. Cryptosporidium was not detected by microscopy, nor using the PCR technique on intestinal tissues from any of the 68 seals examined.

Coyotes from southern Alberta and Saskatchewan, Canada, were examined for the presence of Giardia and Cryptosporidium and cohabiting helminths. Toxascaris was present in over 90% of the 70 animals examined, and Taenia sp. in 6.5-25% of the two groups of animals studied. Giardia (12.5-21.7%) and Cryptosporidium (0-17.4%) were also common and molecular characterisation revealed both zoonotic and host-adapted genotypes of Giardia, whereas the Cryptosporidium proved to be a variant of the canine species C. canis. The seasonal variation observed in the occurrence of Cryptosporidium may be related to stress-induced shedding of the parasite.

Stem cells in mammary tissue have been well characterised by using the mammary stem cell marker, cytokeratin (CK) 5 and the mature epithelial markers CK14, CK18 and CK19. As these markers have never been reported in cells from breastmilk, the aim of this study has been to determine whether mammary stem cells are present in expressed human breastmilk. Cultured cells from human breastmilk were studied by using immunofluorescent labelling and reverse transcription/polymerase chain reaction (RT-PCR). We found a heterogeneous population of cells with differential expression of CK5, CK14, CK18 and CK19. Further, by using the multipotent stem cell marker, nestin, we identified cells in culture that were positive only for nestin or double-positive for CK5/nestin, whereas no co-staining was observed for CK14, CK18 and CK19 with nestin. When cells isolated from breastmilk were analysed by using RT-PCR prior to culture, only nestin and CK18 were detected, thereby indicating that breastmilk contained differentiated epithelial and putative stem cells. Furthermore, fluorescence-activated cell-sorting analysis demonstrated, in breastmilk, a small side-population of cells that excluded Hoechst 33342 (a key property of multipotent stem cells). When stained for nestin, the cells in the side-population were positive, whereas those not in the side-population were negative. The presence of nestin-positive putative mammary stem cells suggests that human breastmilk is a readily available and non-invasive source of putative mammary stem cells that may be useful for research into both mammary gland biology and more general stem cell biology.

This collection of abstracts provides an account of four presentations at the 19th International Conference of the World Association for the Advancement of Veterinary Parasitology (WAAVP) (held in New Orleans, LA, USA from 10-14 August 2003) in a symposium session on zoonotic protozoan parasites found in the marine environment and chaired by Ronald Fayer and David Lindsay. The focus was on three genera of parasites of veterinary and public health concern-Toxoplasma, Giardia, and Cryplosporidium with emphasis on their epidemiology in the marine environment.

Cryptosporidium parvum is commonly identified as infecting domestic livestock and humans. Prevalence of C. parvum in pigs has been reported, however, the duration and infection pattern of naturally acquired Cryptosporidium infections in pigs has not been reported. This study was undertaken to investigate the age of oocyst shedding and duration of natural Cryptosporidium parvum infections in pigs from weaning to market weight. Fecal samples were collected from weaned Yorkshire-Landrace piglets (n=33) twice per week until Cryptosporidium oocysts were detected. Upon oocyst detection, fecal samples were collected three times per week and pigs were monitored throughout the study for diarrhea and examined after concentration and immunofluroescent staining. Cryptosporidium isolates were genotyped by polymerase chain reaction to amplify the HSP70 gene which was subsequently sequence analyzed. All 33 pigs shed oocysts some time during the study. The mean age of initial oocyst detection was 45.2 days post-weaning with the mean duration of infection 28.7 days. Mean number of Cryptosporidium oocysts was low and declined to zero prior to study completion. Episodes of diarrhea were not associated with oocyst excretion. Genetic sequences were obtained for 10 of the pigs. All of the 10 isolates aligned as the Cryptosporidium parvum 'pig' genotype. This study demonstrates that the age and duration of oocyst shedding in pigs infected with C. parvum porcine genotype is different from other livestock species.

Giardia infections in domestic cattle has come under increasing scrutiny owing to the potential contamination of surface and ground waters through manure distribution on fields and pasture runoff. The objective of the study was to determine the prevalence and genotypes of Giardia duodenalis in beef calves in major beef cow calf farms in Alberta, Canada. Fecal samples were collected from beef calves aged 2-10 weeks at nine farms in Alberta. Samples were examined for the presence of G. duodenalis cysts by immunofluorescent staining. Giardia cysts were found in 168 of the 495 fecal samples examined, with prevalence ranging from 7 to 60% among farms. Genotypic analysis of positive isolates utilizing PCR and sequencing of a 292 bp fragment of the 16S-rRNA locus, revealed the hoofed livestock genotype in 41 of the 42 isolates. One isolate was identical to the Assemblage A genotype. The results of this study demonstrate that beef calves in this area are primarily infected with the livestock genotype which is thought to be specific to artiodactyl hosts and non-infective to humans. This suggests that the Giardia carried by beef cattle may be a minimal zoonotic threat.