An Outbreak of Cholera Associated with an Unprotected Well in Parbatia, Orissa, Eastern India.

In November 2003, an outbreak (41 cases; attack rate–4.3%; no deaths) of severe diarrhoea was reported from a village in Orissa, eastern India. Thirteen of these cases were hospitalized. A matched case-control study was conducted to identify the possible exposure variables. Since all wells were heavily chlorinated immediately after the outbreak, water samples were not tested. The cases were managed symptomatically. Descriptive epidemiology suggested clustering of cases around one public well. Vibrio cholerae El Tor O1, serotype Ogawa was isolated from four of six rectal swabs. The water from the public well was associated with the outbreak (matched odds ratio: 12; 95% confidence interval 1.2-44.1). On the basis of these conclusions, access to the well was barred immediately, and it was protected. This investigation highlighted the broader use of field epidemiology methods to implement public-health actions guided by epidemiologic data to control a cholera epidemic.

Risk factors associated with leptospirosis during an outbreak in Middle Andaman, India.

Background & objectives: Leptospirosis outbreaks occur frequently in North and South Andaman Islands but not in Middle Andaman. In 2002, an outbreak appeared in Middle Andaman for the first time. Although a study on risk factors was conducted in North Andaman, it used seropositivity to define leptospirosis. Since seropositivity might not indicate current leptospiral infection and as no study on risk factors was conducted in Middle Andaman, we carried out this study to identify the risk factors during the outbreak. Methods: A suspected outbreak of leptospirosis occurred in Rangat of Middle Andaman during October - November 2002. Suspected cases were screened for leptospirosis using microscopic agglutination test (MAT). Fifty two patients confirmed to have leptospirosis based on rising titres in MAT on paired sera, and 104 age, sex and neighbourhood seronegative matched controls, were included in the study. A conditional multiple regression by backward elimination process was carried out with acute leptospirosis as the dependent factor and various environmental, occupational and behavioural factors as independent factors. A stratified analysis was also carried out. Results: The presence of cattle in the house, drinking stream water, contact with garbage, walking barefoot and standing in water while working were identified as significant factors associated with leptospirosis. Stratified analysis showed a dose response relationship between number of cattle in the house and the risk of leptospiral infection suugesting that cattle could be a source of infection. Interpretation & conclusions: Identification of the potential risk factors would help understand the transmission dynamics of the disease and formulate public health interventions.

Trends in case detection influenced by leprosy elimination campaigns in certain areas of China.

LECs were carried out from 1998 to 2000 in eight counties of west China. The number of cases detected during the year of LECs was much higher than that detected by routine methods before the year of the LEC. However, the annual number of cases detected during the year after the LEC showed different patterns. One pattern is that the number of new cases detected in the year after the LEC declined to the level similar to that before the year of the LEC. The second pattern is that the number of new cases detected in the year after the LEC declined steeply to less than that detected before the year of the LEC. Following peak case-detection during the year of the LEC, a gradual decrease in the number of new cases was observed in the subsequent years. The repeat LEC brought a weakly rebounding peak case-detection during the year following the first LEC carried out 3 years earlier. The operational, epidemiological and technical factors influencing the trends of case-detection during the LECs are discussed.

An institutional outbreak of leptospirosis in Chennai, South India.

The emergence of an outbreak of leptospirosis in a nurses' hostel in Chennai presented a challenge to identify and control the source of the outbreak. Sixty-nine residents and staff members were interviewed to assess exposure factors. Blood samples from the acute and convalescent patients were tested with the Microscopic Agglutination Test using the serovars prevalent in Chennai. Polymerase Chain Reaction (PCR) was conducted on serum and water samples. Based on preliminary investigation, control measures with standard hygienic measures were instituted. The attack rate was 35%. The epidemic curve suggested continuous or intermittent exposure to infection over a five-week period. Twenty residents (three asymptomatic) developed laboratory confirmed Leptospira icterohemorrhagiae. Residents collected water from an underground storage tank that was filled twice weekly from a mobile water tanker with a bucket on a rope, and the tank was usually left open. PCR tests confirmed the presence of leptospires from this water. Other control measures included cleaning the large backyard with its many stray dogs and rats, chlorinating water supplies, boiling drinking water and health education. No further cases occurred twelve days after implementing control measures. Access to clean water, not only for drinking but also for bathing, brushing and washing is essential to prevent water-borne outbreaks.

Effect of dexamethasone and metopirone on hypothalamic gamma-aminobutyric acid (GABA) and plasma cortisol levels in the female catfish, Clarias batrachus (L.)

Em C. batrachus, o GAMA hipotalâmico aumentou significativamente em resposta ao tratamento durante 7 dias com dexametasona (50 ug/peixe/dia : i.p.). Entretanto, a metopirona (CIBA, 50 ug/peixe/dia : i.p.) baixou acentuadamente o conteúdo do GABA hipotalâmico já a partir do 3. dia de tratamento. Nos peixes submetidos a tratamentos com dexametasona e metopirona o nível de cortisol plasmático apresentou-se significativamente menor. Estes resultados sugerem que o aumento e decréscimo dos níveis do GABA hipotalâmico podem ter um papel estimulador ou inibidor em resposta aos tratamentos com dexametasona ou metopirona