Epidemiology of salmonellosis in California, 1990-1999: morbidity, mortality, and hospitalization costs.

Salmonella is a common cause of bacterial foodborne illness in the United States. The epidemiology and costs of nontyphoidal salmonellosis in California from 1990 through 1999 are described using surveillance, hospitalization, and death data. Trends in Salmonella rates and factors associated with prolonged hospitalization were evaluated using Poisson and linear regression models, respectively. There were 56,660 reported cases, 11,102 hospitalizations, and 74 deaths attributed to Samonella. Reported case and hospital discharge rates have decreased since 1996. Among reported cases, infants had the highest rate (121 cases per 10(5) person-years), followed by children 1-4 years of age (40 cases per 10(5) person-years). The highest hospitalization rates were among the elderly and young children. Most deaths occurred among persons aged 65 or more years (59%). Among hospitalizations, gastroenteritis (61%) and septicemia (23%) were the most common Salmonella diagnoses. Salmonella pneumonia patients were the oldest (median age, 55 years) and Salmonella meningitis patients the youngest (median age, 0.3 years). These two diagnoses were the costliest, approaching 30,000 dollars (median) per hospitalization. Having an acquired immunodeficiency syndrome diagnosis or multiple Salmonella diagnoses was independently associated with prolonged hospitalization. The estimated 10-year hospitalization costs for Salmonella were $200 million. Salmonellosis is a costly disease that disproportionately affects the young and elderly.

Evaluation of a two-test serodiagnostic method for community assessment of Lyme disease in an endemic area.

Epidemiological methods are needed to evaluate community exposure to Borrelia burgdorferi, the causative agent of Lyme disease (LD). For LD serodiagnosis, the Centers for Disease Control and Prevention (CDC) recommends a 2-test approach that involves enzyme immunoassay (EIA) testing and Western immunoblotting (WB) of EIA-equivocal and EIA-positive specimens. The specificity of this approach was evaluated among residents of a LD-endemic community and was compared with WB alone and with a simplified 2-test approach (WB of equivocal EIA only). Participants reporting no previous diagnosis of LD were recruited during a community-wide serosurvey on Block Island, Rhode Island. Of 80 eligible participants, 20 had received LD vaccine. Seven (35%) of 20 vaccinees and 22 (37%) of 60 nonvaccinees reported nonspecific symptoms compatible with LD in the previous year. In this highly LD-endemic community, the overall specificity of the CDC-recommended approach was highest (100%), followed by WB alone (98.7%), then the simplified approach (95%).

Rabies preexposure vaccination among veterinarians and at-risk staff.

OBJECTIVE: To measure rabies preexposure vaccination rate and identify factors potentially associated with lack of vaccination among veterinarians and at-risk staff. DESIGN: Cross-sectional survey. STUDY POPULATION: At-risk veterinary medical association (VMA) members, their staff members, and animal shelter and wildlife rehabilitation center personnel located in a California county. PROCEDURE: A questionnaire was mailed to VMA members and managers of animal shelters and wildlife rehabilitation centers. Respondents were requested to provide data on vaccination history and potential factors associated with vaccination status for themselves and their at-risk staff members. Vaccinated and unvaccinated individuals were compared by use of univariate and logistic regression analyses to identify factors associated with vaccination status. RESULTS: Fifty-eight percent (79/137) of persons who received questionnaires responded; 74 were eligible for the study. Respondents provided data for 47.6% (219/460) of their staff members. The vaccination rate was greater among respondents (85.1 %) than among their staff members (17.5%). Among staff members, age and duration of employment were significantly associated with vaccination status. CONCLUSIONS AND CLINICAL RELEVANCE: A large proportion of at-risk staff members working in veterinary clinics, animal shelters, and wildlife rehabilitation centers in the study area did not receive rabies preexposure vaccination per the Centers for Disease Control and Prevention's published recommendations of the Advisory Committee on Immunization Practices (ACIP). The cost of the preexposure vaccine series may be a barrier, particularly for young employees who are commonly short-term, part-time, or volunteer workers. Efforts are needed to increase awareness of the ACIP recommendations and to increase access to vaccination through agencies such as public health clinics.

An untypeable Shigella flexneri strain associated with an outbreak in California.

Eleven Shigella flexneri (group B) isolates were recovered from epidemiologically linked patrons and food handlers from a restaurant-associated outbreak of shigellosis. Six isolates available for pulsed-field gel electrophoresis were identical. All strains agglutinated in group B and subgroup factor 6 sera but not in group 1 through group 6 sera.

Evaluation of two-test serodiagnostic method for early Lyme disease in clinical practice.

The Centers for Disease Control and Prevention (CDC) recommend a two-test approach for the serodiagnosis of Lyme disease (LD), with EIA testing followed by Western immunoblotting (WB) of EIA-equivocal and -positive specimens. This approach was compared with a simplified two-test approach (WB of EIA equivocals only) and WB alone for early LD. Case-patients with erythema migrans (EM) rash >/=5 cm were recruited from three primary-care practices in LD-endemic areas to provide acute- (S1) and convalescent-phase serum specimens (S2). The simplified approach had the highest sensitivity when either S1 or S2 samples were tested, nearly doubling when S2 were tested, while decreasing slightly for the other two approaches. Accordingly, the simplified approach had the lowest negative likelihood ratio for either S1 or S2. For early LD with EM, the simplified approach performed well and was less costly than the other testing approaches since less WB is required.

Evaluation of the polymerase chain reaction in comparison with other diagnostic methods for the detection of Chlamydia psittaci.

Various diagnostic methods exist for the detection of Chlamydia psittaci. In the current study, the test performance of polymerase chain reaction (PCR) was compared with other testing methods used in the diagnosis of C. psittaci. Tissue and fecal specimens (n = 119) of avian and mammalian origin were tested by PCR and one or more of the following methods: cell culture, enzyme-linked immunosorbent assay, and direct fluorescein-conjugated monoclonal antibody staining. Several gold standards, based on results of testing methods other than PCR, were used to calculate the following test performance characteristics of PCR: sensitivity and specificity, with their 95% confidence intervals; kappa statistics, a measure of intertest agreement; and lambda statistics, a chance-corrected estimate of the sensitivity and specificity. Overall, the test performance characteristics of PCR were low compared with the other testing methods. Possible reasons for the poor test performance of PCR in the current study include destruction of the organisms during storage, interference with the PCR by other reagents, or technical errors.

Epidemic leptospirosis associated with pulmonary hemorrhage-Nicaragua, 1995.

In October 1995, epidemic "hemorrhagic fever," without jaundice or renal manifestations, was reported in rural Nicaragua following heavy flooding; 2259 residents were evaluated for nonmalarial febrile illnesses (cumulative incidence, 6.1%) and 15 (0.7%) died with pulmonary hemorrhage. A case-control study found that case-patients were more likely than controls to have ever walked in creeks (matched odds ratio [MOR], 15.0; 95% confidence interval [CI], 1.7-132.3), have household rodents (MOR, 10.4; 95% CI, 1.1-97.1), or own dogs with titers >/=400 to Leptospira species (MOR, 23.4; 95% CI, 3.6-infinity). Twenty-six of 51 case-patients had serologic or postmortem evidence of acute leptospirosis. Leptospira species were isolated from case-patients and potential animal reservoirs. This leptospirosis epidemic likely resulted from exposure to flood waters contaminated by urine from infected animals, particularly dogs. Leptospirosis should be included in the differential diagnosis for nonmalarial febrile illness, particularly during periods of flooding or when pulmonary hemorrhage occurs.

An interstate outbreak of tick-borne relapsing fever among vacationers at a Rocky Mountain cabin.

In July 1995, an outbreak of acute febrile illness affected 11 (48%) of 23 family members from Nebraska and Kansas who had vacationed at a Colorado cabin in June. Similar symptoms were identified among five (17%) of 30 additional persons from Nebraska, Kansas, Florida, and Texas who had vacationed at the same cabin. Symptoms suggested tick-borne relapsing fever (TBRF). Although no spirochetes were detected in available blood smears from five case-patients, Borrelia hermsii was cultured from the blood of one case-patient and two chipmunks trapped near the cabin. Case-patients were more likely than non-ill cabin visitors to have slept on the floor (odds ratio [OR] = 28.0, 95% confidence interval [CI] = 3.0-258) or in the top bunk bed (OR = 5.2, 95% CI = 1.1-25.1). Tick-borne relapsing fever should considered in the differential diagnosis of fever in patients who have stayed overnight in mountain cabins in the western United States.