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West Nile virus (WNV) can cause large outbreaks of febrile illness and severe neurologic disease. This study estimates the seroprevalence of WNV infection and assesses risk perception and practices regarding potential exposures to mosquitoes of persons in an area with intense epizootics in 1999 and 2000. A serosurvey of persons aged > or = 12 years was conducted in southwestern Connecticut during October 10-15, 2000, using household-based stratified cluster sampling. Participants completed a questionnaire regarding concern for and personal measures taken with respect to WNV and provided a blood sample for WNV testing. Seven hundred thirty persons from 645 households participated. No person tested positive for WNV (95% CI: 0-0.5%). Overall, 44% of persons used mosquito repellent, 56% practiced > or = two personal precautions to avoid mosquitoes, and 61% of households did > or = two mosquito-source reduction activities. In multivariate analyses, using mosquito repellent was associated with age < 50 years, using English as the primary language in the home, being worried about WNV, being a little worried about pesticides, and finding mosquitoes frequently in the home (P<0.05). Females (OR = 2.0; CI = 1.2-2.9) and persons very worried about WNV (OR = 3.8; CI = 2.2-6.5) were more likely to practice > or = two personal precautions. Taking > or = two mosquito source reductions was associated with persons with English as the primary language (OR = 2.0; CI = 1.1-3.5) and finding a dead bird on the property (OR = 1.8; CI = 1.1-2.8). An intense epizootic can occur in an area without having a high risk for infection to humans. A better understanding of why certain people do not take personal protective measures, especially among those aged > or = 50 years and those whose primary language is not English, might be needed if educational campaigns are to prevent future WNV outbreaks.

Laboratory-based surveillance of Lyme disease in Connecticut during 1984 and 1985 identified 3,098 persons with suspected Lyme disease; 1,149 were defined as cases. Lyme disease incidence in Connecticut towns ranged from none to 1,407 cases per 100,000 population in 1985. A comparison of 1985 data with data from 1977 epidemiologic studies indicated that incidence increased by 129 percent to 453 percent in towns previously known to be endemic for Lyme disease and that Lyme disease had spread northward into towns thought to be free of Lyme disease in 1977. Children aged five to 14 years had the highest incidence. Of persons with Lyme disease, 83 percent had erythema migrans, 24 percent had arthritis, 8 percent had neurologic sequelae, and 2 percent had cardiac sequelae. The distribution of symptoms was age-dependent: case-persons less than 20 years old were almost twice as likely to have arthritis than older case-persons (35 percent versus 18 percent). Of persons with arthritis, 92 percent of those less than 20 years of age, compared to 68 percent of older persons, did not have antecedent erythema migrans. We conclude that Lyme disease is increasing in incidence and geographic distribution in Connecticut. Of those with Lyme disease, children may be more likely than adults to develop arthritis and have it as their first major disease manifestation.

On November 7, 1985, a Clostridium perfringens gastroenteritis outbreak occurred in approximately 44% of the 1,362 employees at a Connecticut factory. Although the same foods were served to all three shifts at an employee banquet on November 6, the attack rate was almost twice as high for those who ate on the day shift (attack rate = 50%) than for those on the evening shift (attack rate = 20%) or night shift (attack rate = 29%). Among employees of the day shift, attack rates were highest for those who ate during the first 30 minutes of the 2.5-hour day shift serving period and decreased throughout the serving period. The one-hour evening shift serving period had a similar trend toward higher attack rates earlier in the serving period. Four main-course foods were significantly associated with illness, and over 95% of the employees had eaten each of them. Stratified analysis indicated that gravy was the responsible food and, furthermore, that the decreasing attack rate pattern within serving periods occurred only for those who ate gravy. The gravy had been prepared 12-24 hours in advance of banquet service. After it was prepared, the gravy was improperly cooled and was reheated shortly before and throughout the serving periods. Persons who ate gravy that had been reheated for the longest period of time had the lowest attack rate, probably because they were exposed to a lower concentration of organisms. This outbreak underscores the need for properly reheating food to prevent C. perfringens gastroenteritis and suggests that analysis of attack rate trends may provide important epidemiologic clues to understanding the causes of foodborne disease outbreaks.