Development and Evaluation of Two Simple, Rapid Immunochromatographic Tests for the Detection of Yersinia pestis Antibodies in Humans and Reservoirs

Plague is due to the bacterium Yersinia pestis. It is accidentally transmitted to humans by the bite of infected fleas. Currently, approximately 20 developing countries with very limited infrastructure are still affected. A plague case was defined according to clinical, epidemiological and biological features. Rapid diagnosis and surveillance of the disease are essential for its control. Indeed, the delay of treatment is often rapidly fatal for patients and outbreaks may occur. Bubo aspirate is the most appropriate specimen in case of bubonic plague, but its collection is not always feasible. The main current biological approaches for the diagnosis of human plague are F1 antigen detection, serology for antibody detection by ELISA and Y. pestis isolation. The biological diagnosis of plague remains a challenge because the clinical signs are not specific. In this study, we developed some simple, rapid and affordable tests able to detect specific plague antibodies. These tests can be used as alternative methods for plague diagnosis in the field and for plague surveillance

Clinical, epidemiological, and spatial characteristics of <it>Vibrio parahaemolyticus</it> diarrhea and cholera in the urban slums of Kolkata, India

<p>Abstract</p> <p>Background</p> <p>There is not much information on the differences in clinical, epidemiological and spatial characteristics of diarrhea due to <it>V. cholerae</it> and <it>V. parahaemolyticus</it> from non-coastal areas. We investigated the differences in clinical, epidemiological and spatial characteristics of the two <it>Vibrio</it> species in the urban slums of Kolkata, India.</p> <p>Methods</p> <p>The data of a cluster randomized cholera vaccine trial were used. We restricted the analysis to clusters assigned to placebo. Survival analysis of the time to the first episode was used to analyze risk factors for <it>V. parahaemolyticus</it> diarrhea or cholera. A spatial scan test was used to identify high risk areas for cholera and for <it>V. parahaemolyticus</it> diarrhea.</p> <p>Results</p> <p>In total, 54,519 people from the placebo clusters were assembled. The incidence of cholera (1.30/1000/year) was significantly higher than that of <it>V. parahaemolyticus</it> diarrhea (0.63/1000/year). Cholera incidence was inversely related to age, whereas the risk of <it>V. parahaemolyticus</it> diarrhea was age-independent. The seasonality of diarrhea due to the two <it>Vibrio</it> species was similar. Cholera was distinguished by a higher frequency of severe dehydration, and <it>V. parahaemolyticus</it> diarrhea was by abdominal pain. Hindus and those who live in household not using boiled or treated water were more likely to have <it>V. parahaemolyticus</it> diarrhea. Young age, low socioeconomic status, and living closer to a project healthcare facility were associated with an increased risk for cholera. The high risk area for cholera differed from the high risk area for <it>V. parahaemolyticus</it> diarrhea.</p> <p>Conclusion</p> <p>We report coexistence of the two vibrios in the slums of Kolkata. The two etiologies of diarrhea had a similar seasonality but had distinguishing clinical features. The risk factors and the high risk areas for the two diseases differ from one another suggesting different modes of transmission of these two pathogens.</p