The relationship between E. coli indicator bacteria in well-water and gastrointestinal illnesses in rural families.

OBJECTIVES: To determine the relationship between consumption of E. coli contaminated well-water and gastrointestinal illness in rural families. METHODS: One hundred and eighty-one families with well-water as a drinking source participated in a one-year follow-up study. Water was tested for E. coli bacteria and health outcomes were monitored for house-hold members. RESULTS: E. coli in well-water was significantly associated with gastrointestinal illness in family members, however the relationship was modified by the distance from the septic tank to the well. E. coli had an odds ratio of 2.16 [95% CI 1.04, 4.42] if the septic tank was greater than 20 metres from the well and 0.46 [95% CI 0.07, 2.95] if the septic tank was within 20 metres. CONCLUSIONS: Consumption of contaminated well-water is associated with gastrointestinal illness. E. coli can be a useful marker for detecting wells that pose a potential public health problem in rural areas.

Evaluation of postoperative complications following elective surgeries of dogs and cats at private practices using computer records.

This study was designed to determine the frequency of postoperative complications following elective surgeries (castration, ovariohysterectomy, onychectomy) of dogs and cats from private practices and to evaluate the use of electronic medical records for this type of research. All elective surgeries performed during the study period at 5 private practices were included. The surgical techniques and materials used for each procedure were similar across practices, but the interpretation of "complication," the amount of detail recorded on the primary medical record, and the intensity of follow-up varied. The frequencies and types of complications varied by species and procedure. The postoperative complication frequencies ranged from 1% to 24% for all complications and 1% to 4% for severe complications. The results of this study describe populations of elective-surgery patients at private practices, provide data for educating clients about the risks associated with these procedures, and demonstrate how computerized records can be used to collect practice-specific medical information.

Postoperative complications of elective surgeries in dogs and cats determined by examining electronic and paper medical records.

Postoperative complications (POC) that developed in dogs and cats that underwent elective ovariohysterectomy, castration, and declaw at a veterinary teaching hospital were determined by examining the computerized abstracts of the medical records and by examining a random sample of the paper medical records. When the computerized abstracts were examined, POC were found to have occurred in 62 (6.1%) of 1,016 dogs. One dog died and 6 others developed major complications. Postoperative complications were found to have occurred in 38 (2.6%) of 1,459 cats. Two cats died and 1 was euthanatized. Four other cats developed major complications. Complete paper medical records for 218 dogs and cats were examined. When the paper medical records were examined, the proportions of dogs and cats with POC were 19.4% and 12.2%, respectively. These proportions were 4 to 7 times higher than when the computerized abstracts were the data source. Results of this study indicate that the frequency of clinically relevant POC of elective surgeries in dogs and cats is substantial. Examination of the computerized abstracts of medical records at this hospital allowed us to rapidly identify cases that could be included in the study but the frequency of POC would be significantly underestimated if paper records were not also assessed.

A serological survey of bovine syncytial virus in Ontario: associations with bovine leukemia and immunodeficiency-like viruses, production records, and management practices.

Of the 920 cows tested, 56.7% showed antiretroviral serological reactivity. Prevalence rates (95% confidence interval) of antiretroviral antibodies among individual dairy cows in Ontario were: BIV 5.5% (4.0-7.0), BLV 25.7% (22.9-28.6), and BSV 39.6% (36.4-42.8). The following percentages of cows showed serological reactivity against the specified retroviruses: BIV 2.3%, BLV 14.0%, BSV 27.5%, BIV and BSV 1.3%, BIV and BLV 0.9%, BLV and BSV 9.9%, BIV and BLV and BSV 0.9%. These rates of sero-positivity are similar to those found in other countries. Serological test results were not adjusted for sensitivity and specificity. The prevalence rates of antibodies to the three retroviruses (BIV, BLV, and BSV) were significantly different, but no associations were observed between specific retroviral serological test results among individual cows. The prevalence rates of BIV and BSV seropositivity were constant across Ontario, whereas, there was a significant trend for the prevalence rate of BLV seropositivity to decrease going from southwestern to eastern Ontario; cows in eastern Ontario had approximately half the prevalence rate of those in southwestern Ontario. Cows that were seropositive for BSV were significantly older than BSV seronegative cows. There was no association between culling rate and BSV serology. Significant negative associations were found with winter or summer housing of calves separate from adults and summer outdoor exercise for dry cows. The use of calf hutches in the summer had a significant positive association with BSV seropositivity. Regression analyses were done to assess the association of retroviral (BIV, BLV, and BSV) seropositivity on calving interval, milk somatic cell count, and milk production. Serological test results for BIV, BLV, and BSV were entered into all models and all models were adjusted for intra-cluster (intraherd) correlation. Herd size and age were found to be important confounding variables. BIV seropositivity was not associated with any changes in production using this approach, however when considered in isolation BIV seropositivity remained associated with decreased milk production. BLV seropositivity was significantly associated with longer calving intervals and higher somatic cell counts in older cows. As well, in older cows, BSV seropositivity was significantly associated with higher milk production.

Use of survival analysis to compare cull rates between bovine leukemia virus seropositive and seronegative dairy cows.

Bovine leukemia virus (BLV) infection and culling of cows in a commercial dairy herd were evaluated to determine whether a relation existed between the 2 factors. Cattle from the study population, a Holstein dairy herd consisting of approximately 400 milking cows, were tested for antibodies to BLV, using the agar gel immunodiffusion test, semiannually for 2 years, annually for 2 years, and when cattle were culled. Complete records of BLV test results were available for 849 (79%) of the 1,078 cattle that had at least 1 test during the study period. Using the Cox hazard model, the cull hazard rates (culls/cow-months) were greater for BLV seropositive cows than for seronegative cows > 36 months old. Hence, among older dairy cows, BLV-infected cows were culled prematurely, compared with uninfected cows.

Effects of bovine leukemia virus infection on production and reproduction in dairy cattle.

The purpose of this study was to determine the effects of bovine leukemia virus (BLV) infection on production, reproduction and longevity in dairy cattle. The study population was a commercial Holstein dairy herd of approximately 400 milking cows. Cattle were tested for antibodies to BLV at least annually for three years and when culled. Four groups of culled cows were compared: seronegative cows (n = 79), seropositive cows without lymphocytosis (n = 176), seropositive cows with lymphocytosis (> or = 9,000 lymphocytes/microliter) (n = 74), and seropositive cows with lymphosarcoma (n = 29). Seropositive groups of cows were bred more times and had longer calving intervals than seronegative cows. The seropositive groups had greater 305-day ME (mature equivalent) FCM (3.5% fat-corrected milk) per lactation and were older when culled than seronegative cows. However, the percent fat per lactation was greater in seronegative cows. In the last complete lactation, differences in 305-day ME FCM, days open and cull age between groups were reduced and none were significant (p > 0.05). In the cull lactation, only cows with lymphocytosis had reduced milk production relative to seronegative cows, although this difference was not significant. After adjustment for initial production and reproductive values, only seropositive nonlymphocytotic cows were culled at a significantly older age than seronegative cattle. Lymphocytotic cows were culled four months younger on average than nonlymphocytotic seropositive cows. Hence, BLV infected cows had greater milk production on average than uninfected cows. Adverse effects of BLV infection were primarily limited to lymphocytotic cows which were culled earlier and had reduced milk production in the cull lactation.

Scanning electron microscopy of merogonous stages of Eimeria falciformis var. pragensis in Mus musculus.

Asexual stages of Eimeria falciformis var. pragensis in Swiss-Webster mice were studied by scanning electron microscopy. Sporozoites were present in the cecum and colon 2 h post-inoculation (PI) and measured 11.3 X 2.1 micrometer (9-13.9 X 2-2.2 micrometer). Sporozoites penetrated epithelial cells with an extended anterior end and were constricted at the site of entry. Asexual generations were found in the cecum and colon epithelial cells. In meronts found at days 3-9 PI, merozoites matured synchronously, were oriented in the same direction, and were arranged in a helical pattern. Such meronts measured 11.3 X 6.4 micrometer (8-13.7 X 5-7.4 micrometer) and contained 8-12 merozoites, which measured 11.9 X 1.5 micrometer (7.4-15.7 X 1.3-1.8 micrometer). Meronts which were present at day 7 PI measured 9.5 X 8.2 micrometer (9-10.5 X 7-9.5 micrometer) and contained 20-50 small merozoites which budded asynchronously from a central residuum. At days 3-7 PI, parasitized epithelial cells had shorter and fewer or no microvilli. The lumenal plasmalemma of the host cell was often disrupted or absent in cells containing mature meronts and escaping merozoites. At day 6 PI, phagocytic cells appeared on the epithelial surface, some of which were in contact with merozoites. Small foci of exposed basal lamina were present at day 7 PI in areas where cells had sloughed from the epithelium.