Risk factors for Toxoplasma gondii seropositivity in the Old Order Amish.

Toxoplasma gondii (T. gondii) is an important human disease-causing parasite. In the USA, T. gondii infects >10% of the population, accrues economic losses of US$3.6 billion/year, and ranks as the second leading culprit of foodborne illness-related fatalities. We assessed toxoplasmosis risk among the Old Order Amish, a mostly homogenous population with a high prevalence of T. gondii seropositivity, using a questionnaire focusing on food consumption/preparation behaviours and environmental risk factors. Analyses were conducted using multiple logistic regression. Consuming raw meat, rare meat, or unpasteurised cow or goat milk products was associated with increased odds of seropositivity (unadjusted Odds Ratios: 2.192, 1.613, and 1.718 , respectively). In separate models by sex, consuming raw meat, or consuming unpasteurised cow or goat milk products, was associated with increased odds of seropositivity among women; washing hands after touching meat with decreased odds of seropositivity among women (adjusted OR (AOR): 0.462); and cleaning cat litterbox with increased odds of seropositivity among men (AOR: 5.241). This is the first study to assess associations between behavioural and environmental risk factors and T. gondii seropositivity in a US population with high seroprevalence for T. gondii. Our study emphasises the importance of proper food safety behaviours to avoid the risk of infection.

Distribution of Antimicrobial Resistance Genes Across Salmonella enterica Isolates from Animal and Nonanimal Foods.

ABSTRACT: Antimicrobial-resistant bacteria are a major public health problem. Of particular importance in the context of food safety is the prevalence of antimicrobial resistance (AMR) genes within nontyphoidal Salmonella, which is a leading bacterial cause of foodborne disease. We determined the prevalence of AMR genes across a very large number of Salmonella genomes (n = 25,647) collected from isolates from 16 common food sources. The average percentage of isolates from nonanimal foods, such as fruit, nuts and seeds, and vegetables, harboring at least one AMR gene was only marginally lower (72%) than that observed in isolates from animal foods such as beef, chicken, turkey, and pork (74%). This high prevalence of AMR genes was primarily driven by the high prevalence of aminoglycoside resistance genes in nearly all food isolates; genes for resistance to tetracycline and sulfonamide also were highly prevalent. However, evaluation of the number of genes per isolate revealed that the prevalence of AMR genes was higher in animal food isolates than in nonanimal food isolates (P = 0.018). A random forest analysis provided evidence that within a given serovar, resistance gene profiles differed according to isolate food source. AMR gene profiles could be used to correctly predict the food of origin for 71% of the isolates, but success differed according to serovar. This information can help inform AMR risk assessments of food commodities and refine processes for targeting interventions to limit the spread of AMR through the food supply.

Hepatitis B virus transmission between children in day care.

We investigated two situations involving hepatitis B virus exposure among children in day care. In the first a 4-year-old boy who attended a day care center developed acute hepatitis B; another child at the center, who had a history of aggressive behavior (biting/scratching), was subsequently found to be a hepatitis B carrier. No other source of infection among family and other contacts was identified and no other persons at the center became infected. In the second situation a 4-year-old boy with frequently bleeding eczematous lesions was discovered to be a hepatitis B carrier after having attended a day care center for 17 months. Testing of contacts at the center revealed no transmission to other children or staff (representing 887 person months of exposure). Nationwide surveillance data showed that for the period 1983 to 1987, 161 children 1 to 4 years of age were reported with acute hepatitis B. After children with known hepatitis B risk factors were excluded, 25% (7 of 28) of children with known day care status were reported as day care attendees, a percentage comparable to national estimates of day care attendance by this age group. This is the first reported case of hepatitis B virus transmission between children in day care in the United States. Although it appears that day care transmission of hepatitis B is infrequent, further studies are needed to define the risk more accurately.

Low seroprevalence of human Lyme disease near a focus of high entomologic risk.

To investigate a low rate of reported human Lyme disease adjacent to an area where the vector tick had become well established, we performed human and canine serosurveys and gathered data on environmental factors related to the risk of transmission. In March 1993, we obtained serum samples and conducted questionnaires that included information on outdoor activities, lot size, and frequency of deer sightings from 272 individuals living within a 5-km strip extending 12 km inland from a study site in south coastal Maine where collections revealed an abundant population of deer ticks. Serologic analysis was done using a flagellin-based enzyme-linked immunosorbent assay (ELISA) followed by Western immunoblot of positive and equivocal samples. Sera from 71 unvaccinated dogs within the study area were also analyzed for anti-Borrelia antibodies by ELISA. Human seropositivity was limited to two individuals living within 1.2 km of the coast. The frequency of daily deer sightings decreased sharply outside this area. Canine seropositivity, 100% within the first 0.8 km, decreased to 2% beyond 1.5 km. Canine serology appears to correlate with the entomologic indicators of the risk of Lyme disease transmission. Possible explanations for the low human seroprevalence are offered.

Physicians and medical students: factors affecting entry into public health.

We surveyed members of a recent master of public health (MPH) degree program to learn more about how, when, and why physicians and medical students decided to seek formal training in public health. We interviewed physicians and medical students to determine how and why these MPH students became involved in what they considered public health work; how and why they decided to attend public health school; and what their career plans were following completion of the degree program. All 47 medical students and physicians responded to the survey. Sixty-six percent described previous public health-related work experience. Only 5% decided prior to or during college to attend public health school. A personal contact directed 62% towards public health school. Those with previous public health work experience were more likely to pursue what they considered public health careers after completion of public health school than those without such previous work experience. The continuing need for qualified practitioners and leaders in public health challenges the medical community to characterize further those factors motivating medical students and physicians to formalize their training in public health.

Challenges and opportunities in pandemic influenza planning: lessons learned from recent infectious disease preparedness and response efforts.

The impact of the next pandemic influenza is likely to be far greater, by orders of magnitude, than most bioterrorism (BT) scenarios. A written pandemic emergency plan and establishment of emergency management teams are critical to mounting a coordinated and effective response to what will be a catastrophic event. Members of these teams should include public health, medical, emergency response and public safety officials, organized at each local, state and federal level. The tragic events of September 11, 2001 and the subsequent anthrax attacks have substantially increased funding and support for bioterrorism planning in the United States. Thus, public health officials have an unprecedented opportunity to strengthen current systems' planning efforts by promoting dual use bioterrorism/pandemic influenza plans. Combining lessons learned from the 2001 terrorist incidents, recent preevent smallpox vaccine programs and the history of past influenza pandemics, more effective strategies can be developed. For example, enhanced influenza surveillance systems can provide data that will not only provide early identification of a novel influenza strain, but will provide more timely recognition of other outbreaks of infectious diseases, including public health threats that may initially present as an influenza-like illness (ILI). In recent years, we have witnessed emerging and reemerging infectious disease threats that have presented us with challenges similar to those posed by an influenza pandemic. Such events highlight the need for advance planning to ensure an optimal response to a health emergency that is certain to be unpredictable, complex, rapidly evolving and accompanied by considerable public alarm. While advance warning for a terrorist attack is unlikely, the warning already exists for a possible new influenza strain, as evidenced by the recent cases of H5N1 in Hong Kong and the rapid global spread of cases of Severe Acute Respiratory Syndrome.

An outbreak of cat-associated Q fever in the United States.

Q fever is usually acquired by contact with aerosols generated during parturition of domestic ungulates (e.g., sheep, cows, goats). In the maritime provinces of Canada, parturient cats have also been implicated in its transmission. A 66-year-old woman from eastern Maine developed high fever, rigors, headache, myalgias, pulmonary infiltrates, and elevated hepatocellular enzymes, and the diagnosis of acute Q fever was confirmed serologically. She and 14 other family members had attended a family reunion in Maine 2 weeks earlier, when they were exposed to a parturient cat. All 11 adults and older children attending the reunion developed symptoms consistent with acute Q fever. Serum samples were obtained from 10 who attended the reunion and 8 who did not attend. Titers greater than or equal to 1:64 to Coxiella burnetii were present in all who attended the reunion but in none of those who did not. Cat-associated Q fever should be considered when sporadic cases of the disease occur in the United States.

An outbreak of cryptosporidiosis from fresh-pressed apple cider.

BACKGROUND: Recent waterborne outbreaks have established Cryptosporidium as an emerging enteric pathogen, but foodborne transmission has rarely been reported. In October 1993, an outbreak of cryptosporidiosis occurred among students and staff attending a 1-day school agricultural fair in central Maine. DESIGN: Environmental/laboratory investigation and cohort study. PARTICIPANTS: Attendees of the fair and their household members. MAIN OUTCOME MEASURES: Clinical or laboratory-confirmed cryptosporidiosis. Clinical cryptosporidiosis was defined as 3 days of either diarrhea (three loose stools in a 24-hour period) or vomiting. RESULTS: Surveys were completed for 611 (81%) of the estimated 759 fair attendees. Among attendees who completed the survey, there were 160 (26%) primary cases. Cryptosporidium oocysts were detected in the stools of 50 (89%) of 56 primary and secondary case patients tested. The median incubation period was 6 days (range, 10 hours to 13 days); the median duration of illness was 6 days (range, 1 to 16 days). Eighty-four percent of primary case patients had diarrhea and 82% had vomiting. Persons drinking apple cider that was hand pressed in the afternoon were at increased risk for cryptosporidiosis (154 [54%] of 284 exposed vs six [2%] of 292 unexposed; relative risk, 26; 95% confidence interval, 12 to 59). Cryptosporidium oocysts were detected in the apple cider, on the cider press, and in the stool specimen of a calf on the farm that supplied the apples. The secondary household transmission rate was 15% (53/353). CONCLUSIONS: This is the first large cryptosporidiosis outbreak in which foodborne transmission has been documented. It underscores the need for agricultural producers to take measures to avoid contamination of foodstuffs with infectious agents common to the farm environment.

Predisposing factors for individuals' Lyme disease prevention practices: Connecticut, Maine, and Montana.

OBJECTIVES: This study examined factors that predispose individuals to protect against Lyme disease. METHODS: Knowledge, attitude, and practice questions concerning Lyme disease prevention were included in the Behavioral Risk Factor Surveillance surveys in Connecticut, Maine, and Montana. A total of 4246 persons were interviewed. RESULTS: Perceived risk of acquiring Lyme disease, knowing anyone with Lyme disease, knowledge about Lyme disease, and believing Lyme disease to be a common problem were significantly associated with prevention practices. CONCLUSIONS: Predisposing factors differ substantially between states and appear related to disease incidence. Personal risk, knowing someone with Lyme disease, and cognizance about Lyme disease and acting on this information are consistent with social learning theories.

A multistate, foodborne outbreak of hepatitis A. National Hepatitis A Investigation Team.

BACKGROUND: We investigated a large, foodborne outbreak of hepatitis A that occurred in February and March 1997 in Michigan and then extended the investigation to determine whether it was related to sporadic cases reported in other states among persons who had consumed frozen strawberries, the food suspected of causing the outbreak. METHODS: The cases of hepatitis A were serologically confirmed. Epidemiologic studies were conducted in the two states with sufficient numbers of cases, Michigan and Maine. Hepatitis A virus RNA detected in clinical specimens was sequenced to determine the relatedness of the virus from outbreak-related cases and other cases. RESULTS: A total of 213 cases of hepatitis A were reported from 23 schools in Michigan and 29 cases from 13 schools in Maine, with the median rate of attack ranging from 0.2 to 14 percent. Hepatitis A was associated with the consumption of frozen strawberries in a case-control study (odds ratio for the disease, 8.3; 95 percent confidence interval, 2.1 to 33) and a cohort study (relative risk of infection, 7.5; 95 percent confidence interval, 1.1 to 53) in Michigan and in a case-control study in Maine (odds ratio for infection, 3.4; 95 percent confidence interval, 1.0 to 14). The genetic sequences of viruses from 126 patients in Michigan and Maine were identical to one another and to those from 5 patients in Wisconsin and 7 patients in Arizona, all of whom attended schools where frozen strawberries from the same processor had been served, and to those in 2 patients from Louisiana, both of whom had consumed commercially prepared products containing frozen strawberries from the same processor. CONCLUSIONS: We describe a large outbreak of hepatitis A in Michigan that was associated with the consumption of frozen strawberries. We found apparently sporadic cases in other states that could be linked to the same source by viral genetic analysis.