Diversity of gastrointestinal helminths in Dall's sheep and the negative association of the abomasal nematode, Marshallagia marshalli, with fitness indicators.

Gastrointestinal helminths can have a detrimental effect on the fitness of wild ungulates. Arctic and Subarctic ecosystems are ideal for the study of host-parasite interactions due to the comparatively simple ecological interactions and limited confounding factors. We used a unique dataset assembled in the early seventies to study the diversity of gastrointestinal helminths and their effect on fitness indicators of Dall's sheep, Ovis dalli dalli, in the Mackenzie Mountains, Northwest Territories, Canada. Parasite diversity included nine species, among which the abomasal nematode Marshallagia marshalli occurred with the highest prevalence and infection intensity. The intensity of M. marshalli increased with age and was negatively associated with body condition and pregnancy status in Dall's sheep across all the analyses performed. The intensity of the intestinal whipworm, Trichuris schumakovitschi, decreased with age. No other parasites were significantly associated with age, body condition, or pregnancy. Our study suggests that M. marshalli might negatively influence fitness of adult female Dall's sheep.

Global Perspectives on Escherichia coli O157:H7 and Other Verocytotoxic E. coli spp.: UK Views †.

This paper is based on the findings of a verocytotoxic Escherichia coli (VTEC) Working Group of the UK Advisory Committee on the Microbiological Safety of Food. In 1994, 95% of UK diagnostic laboratories examined selected, usually bloody diarrheal, stool samples for E. coli O157:H7. The Group recommended that all diarrheal stool samples should be so examined. Most cases of VTEC infection in the UK are caused by E. coli O157:H7. The number of fecal isolates rose from 1 in 1982 to a provisional 1,039 in 1995. VTEC infection is most common in summer and in the 0- to 4-year-old age group. Overall, about 10% of patients with hemorrhagic colitis develop the hemolytic uremic syndrome. Most hemorrhagic colitis outbreaks affect fewer than 10 people. Between 1992 and 1994 there were 18 general outbreaks, 8 of which were considered to be foodborne. In the United Kingdom E. coli O157:H7 has been found in about 0.5% of bovine carcasses and in the feces of about 1% of live cattle. The UK government is funding a wide variety of VTEC research. Guidelines on public health measures to control VTEC infection have been published. Industry has been urged to adopt Hazard Analysis Critical Control Point systems. Industry has also been urged to label raw ground beef and ground beef products with cooking instructions that should be capable of achieving an internal temperature of 70°C for 2 min or the equivalent "so that the burger's juices run clear and there are no pink bits inside."