Syndromic Surveillance of Norovirus using Over-the-counter Sales of Medications Related to Gastrointestinal Illness.

OBJECTIVE: To assess whether over-the-counter (OTC) sales of gastrointestinal illness (GI)-related medications are associated with temporal trends of reportable community viral, bacterial and parasitic infections. METHODS: The temporal patterns in weekly and seasonal sales of nonprescription products related to GI were compared with those of reportable viral, bacterial and parasitic infections in a Canadian province. RESULTS: Temporal patterns of OTC product sales and Norovirus activity were similar, both having highest activity in the winter months. In contrast, GI cases from both bacterial and parasitic agents were highest from late spring through to early fall. CONCLUSIONS: Nonprescription sales of antidiarrheal and antinauseant products are a good predictor of community Norovirus activity. Syndromic surveillance through monitoring of OTC product sales could be useful as an early indicator of the Norovirus season, allowing for appropriate interventions to reduce the number of infections.

Efficacy of tilmicosin in the control of experimentally induced Actinobacillus pleuropneumoniae infection in swine.

The efficacy of tilmicosin administered in the feed to control Actinobacillus pleuropneumoniae infections in pigs was evaluated through a multisite, multitrial study. For each of 6 trials, 48 pigs (stratified by weight and sex) were randomly assigned to 6 to 8 pens. Medicated feed containing tilmicosin (200 g/t) and unmedicated feed were randomly assigned at the pen level and were provided ad libitum from day -7 to trial termination (day 14). Seeder pigs (inoculated intranasally with A. pleuropneumoniae serotype 1 and showing signs of clinical disease) were introduced to each pen on day 0. Rates of death, gross lesions, and culture of A. pleuropneumoniae at necropsy, clinical scores, average daily gain in weight, and average body temperature were compared between the medicated and unmedicated pigs. Compared with the unmedicated pigs, significantly fewer (P < 0.05) pigs given tilmicosin had lesions typical of A. pleuropneumoniae or had A. pleuropneumoniae isolated from their tissues at necropsy. Together with a significant reduction (P < 0.05) in the average percentage of pneumonic lung involvement (both visually and by weight), there were reductions in the numbers of pigs with moderate and severe pneumonic lung lesions and with A. pleuropneumoniae associated mortality. With tilmicosin treatment, the average daily weight gain, daily temperature, abdominal appearance, attitude, and respiration were also significantly better (P < 0.05). The results of this study demonstrate the in vivo effectiveness of tilmicosin (200 g/t) in controlling pleuropneumonia among swine experimentally infected with A. pleuropneumoniae.

Associations between indicators of livestock farming intensity and incidence of human Shiga toxin-producing Escherichia coli infection.

The impact of livestock farming on the incidence of human Shiga toxin-producing Escherichia coli (STEC) infection was assessed by using several livestock density indicators (LDI) that were generated in a systematic approach. A total of 80 LDI were considered suitable proxy measures for livestock density. Multivariate Poisson regression identified several LDI as having a significant spatial association with the incidence of human STEC infection. The strongest associations with human STEC infection were the ratio of beef cattle number to human population and the application of manure to the surface of agricultural land by a solid spreader and by a liquid spreader. This study demonstrates the value of using a systematic approach in identifying LDI and other spatial predictors of disease.

Increased burden of illness associated with antimicrobial-resistant Salmonella enterica serotype typhimurium infections.

This study investigated the burden of illness associated with 440 cases of Salmonella enterica serotype Typhimurium infection identified in Canada between December 1999 and November 2000. We categorized case subjects' infections by definitive phage type 104 (DT104) and antimicrobial-resistance patterns. These variables were then investigated as risk factors for hospitalization. Hospitalization was more likely to occur among case subjects whose infections were resistant to at least ampicillin, chloramphenicol and/or kanamycin, streptomycin, sulphamethoxazole, and tetracycline (R-type AK/CSSuT; odds ratio [OR], 2.3; P=.003), compared with case subjects with AK/CSSuT-susceptible infections, and among case subjects with non-DT104 R-type AKSSuT infections (OR, 3.6; P=.005), compared with case subjects with non-DT104 AKSSuT-susceptible infections. In contrast, hospitalization rates did not differ between case subjects with DT104 infections and case subjects with non-DT104 infections or between case subjects with DT104 R-type ACSSuT infections and case subjects with DT104 ACSSuT-susceptible infections. We estimated that 57% of the hospitalizations among AK/CSSuT case subjects and 72% of the hospitalizations among non-DT104 AKSSuT case subjects were attributable to the resistance patterns of the infections.

Canadian Perspectives on Verocytotoxin-Producing Escherichia coli Infection †.

Infection with verocytotoxin-producing Escherichia coli (VTEC) became nationally reportable in 1990. Between 1990 and 1994, the national incidence of reported infections ranged from 3 to 5.3 per 100,000 inhabitants. Most cases are sporadic and are caused by E. coli O157:H7. Recent investigations have identified that, in addition to exposure to undercooked ground beef, contact with cattle, consumption of well water, and exposure to rural environments are important risk factors for VTEC infection. Also, results of case control studies and detection of asymptomatic fecal carriage of E. coli O157:H7 and other VTEC in farm family members and abattoir workers have led to an increasing emphasis on person-to-person spread in the epidemiology of VTEC infection. Controlling E. coli O157:H7 and other VTEC at the farm level may therefore have a broader impact than simply reducing the risk of foodborne VTEC infection. Longitudinal studies on dairy farms have demonstrated that E. coli O157:H7 carriage by cattle at the farm and animal level is often transient, and that cattle, rather than the farm environment, are the major reservoir for this organism on dairy farms. Small herds that are controlled by traditional management practices have the highest risk for VTEC infection. Further studies are likely to result in development of effective strategies to control VTEC at the farm level.