The burden of cholera in the slums of Kolkata, India: data from a prospective, community based study

AIMS

To conduct a prospective, community based study in an impoverished urban site in Kolkata (formerly Calcutta) in order to measure the burden of cholera, describe its epidemiology, and search for potential risk factors that could be addressed by public health strategies.

METHODS

The study population was enumerated at the beginning and end of the study period. Surveillance through five field outposts and two referral hospitals for acute, watery, non-bloody diarrhoea was conducted from 1 May 2003 to 30 April 2004. Data and a stool sample for culture of Vibrio cholerae were collected from each patient. Treatment was provided in accordance with national guidelines.

RESULTS

From 62 329 individuals under surveillance, 3284 diarrhoea episodes were detected, of which 3276 (99%) had a stool sample collected and 126 (4%) were culture confirmed cholera. Nineteen (15%) were children less than 2 years of age, 29 (23%) had severe dehydration, and 48 (38%) were hospitalised. Risk factors for cholera included a household member with cholera during the period of surveillance, young age, and lower educational level.

CONCLUSIONS

There was a substantial burden of cholera in Kolkata with risk factors not easily amenable to intervention. Young children bear the brunt not only of diarrhoeal diseases in general, but of cholera as well. Mass vaccination could be a potentially useful tool to prevent and control seasonal cholera in this community.

Shigellosis remains an important problem in children less than 5 years of age in Thailand

This is a review of existing data on the burden of shigellosis in Thailand to determine trends, vulnerable groups, predominant species and serotypes, and antimicrobial resistance patterns. Diarrhoea and dysentery morbidity and mortality data from 1991 to 1999 was collected from the routine surveillance system and demographic data from the government census. International and local literature published between 1988 and 2000 was systematically reviewed. Based on the routine surveillance system, the annual incidence of bacillary dysentery decreased from 1.3 to 0.2/10,000 persons per year. The remaining burden is highest in children <5 years of age at 2.7/10,000 persons per year. In comparison, a prospective study utilizing active surveillance found an incidence in children <5 years of age that was more than 100-fold higher at 640/10,000 persons per year. Despite the decrease in morbidity and mortality based on routinely collected data, shigellosis remains an important problem in children <5 years of age in Thailand.

Evolution in the recommendations for oral rehydration therapy according to World Health Organisation guidelines: where to go from here?

Guidelines on the use of oral rehydration salts (ORS) have been revised over the years based on evidence from research studies and clinical experience. This paper charts the evolution in oral rehydration therapy (ORT) in the context of World Health Organisation (WHO) recommendations. Diarrhoeal disease case management, with ORT as its cornerstone, has had tremendous success in terms of implementation and outcome. To further decrease global diarrhoeal morbidity and mortality, there should be increased efforts to accelerate the introduction of safe, effective, and affordable against diarrhoeal pathogens such as cholera and rotavirus.

An extended field test of the WHO severe malnutrition guidelines in hospitals in developing countries: preliminary observations

The WHO has published guidelines for the inpatient management of severe malnutrition. A qualitative study in hospitals in developing countries is being conducted to document the re-organisation of the clinical ward and support services required to implement these guidelines and to gain an impression of the feasibility and sustainability of such a re-organisation. Following a postal survey of experts in the management of malnutrition in children in developing countries, hospitals were contacted and asked if they were interested to participate in the study. If so, they were requested to submit background information about admission patterns, the frequency of malnutrition, and current practice. Based on this information, hospitals are selected for a preliminary visit. Following this, and the final selection, a paediatrician conducts three visits to the study hospital over a one-year period to appraise the current practice, assist the health staff in recognising the strengths and shortcomings of their current management, help them find locally appropriate solutions, support the implementation process through a participatory approach and assess the outcome. A structured survey instrument is used to guide the assessment and identification of problems. Results of the first visit, which documents the existing situation, and changes identified by staff and implemented during the second visit are presented.

Increased risk for malaria in chronically malnourished children under 5 years of age in rural Gambia

Malaria and malnutrition cause high morbidity and mortality in rural sub-Saharan Africa. To explore the relationship between nutritional status and malaria, a cohort of Gambian children under 5 years of age was followed weekly during one malaria season. Anthropometric measurements were made at the beginning and at the end of the season. A total of 55/107 (51.4 per cent) children with baseline stunting, defined as having a height-for-age z-score below -2 standard deviations, subsequently experienced malaria episodes, compared to 145/380 (38.2 per cent) children who were not stunted (RR = 1.35; 95 per cent CI, 1.08-1.69; p value = 0.01). Neither wasting (weight-for-height z-score below -2 standard deviations) nor undernutrition (weight-for-age z-score below -2 standard deviations) influenced susceptibility to malaria. Adjustment for characteristics of age, sex, and ethnicity did not significantly change the risk ratios. Malaria had no effect on the nutritional status from the beginning to the end of the malaria season. Our findings suggest that chronically malnourished children may be at higher risk for developing malaria episodes.

The safety of the combination artesunate and pyrimethamine-sulfadoxine given during pregnancy

Malaria during pregnancy is associated with an increased risk of severe anaemia and low-birthweight babies. Effective intermittent therapy with pyrimethamine-sulfadoxine (PSD) decreases parasitaemia and severe anaemia and improves birthweight in areas where Plasmodium falciparum is sensitive to this drug. Increasing resistance to PSD is a concern and alternative antimalarial regimens during pregnancy are needed. Artesunate with PSD is a promising antimalarial combination but few data are available on the safety of artemisinins when taken during pregnancy. Outcome of pregnancy was evaluated for 287 women in The Gambia who were exposed in June 1999 to a single dose of the combination artesunate and PSD during a mass drug administration and 172 women who were not exposed. Women who received placebo (40) and those who did not participate in the mass drug administration (132) comprised the non-exposed group. There was no difference in the proportion of abortions, stillbirths, or infant deaths among those exposed or not exposed to the drugs. The mean weight of 18 infants born to mothers who had received artesunate and PSD during the third trimester was 3.10 kg compared to a mean weight of 2.62 kg of the 10 infants of untreated mothers (adjusted P value = 0.05). We found no evidence of a teratogenic or otherwise harmful effect of gestational exposure to artesunate and PSD. Treatment of a self-selected group of pregnant women with PSD and artesunate during pregnancy was associated with a greater birthweight, which may have resulted from clearance of malaria parasites. However, the influence of confounding factors cannot be excluded.

Community perceptions of a mass administration of an antimalarial drug combination in The Gambia

To test the hypothesis that widespread treatment with artemisinin derivatives can reduce malaria transmission, a mass drug administration (MDA) campaign was undertaken in an area of The Gambia in 1999. Coverage of 85% of the target population was achieved, but the intervention did not reduce overall malaria transmission. We studied the perceptions, knowledge and attitudes of the community to the MDA campaign. A validated questionnaire was administered to randomly selected MDA participants (n = 90) and MDA refusers (n = 71). Individuals who believed in the importance of the MDA (adjusted OR 58.3%; 95% CI 17.4-195.8) and those who were aware that a high level of participation was needed for the MDA to be successful (adjusted OR 28.1; 95% CI 10.3-75.9) were more likely to participate. Understanding that the purpose of the MDA was to reduce malaria (adjusted OR 13.9; 95% CI 5.5-35.1) and knowledge of the fact that malaria is transmitted by mosquitoes and of the clinical signs of malaria (adjusted OR 3.4; 95% CI 3.1-9.0) were associated with participation. Individuals who discussed the MDA with other villagers (adjusted OR 5.5; 95% CI 2.2-13.5) and those who attended the sensitization meeting (adjusted OR 2.6; 95% CI 1.1-6.0) were also more likely to participate. Women were significantly more likely to participate in the MDA than men (adjusted OR 3.1; 95% CI 1.5-6.2). Individuals who refused to participate were unlikely to plan participation in future MDAs. One of the most difficult challenges in the implementation of a malaria control strategy such as an MDA is to convince villagers to participate and to make them aware that a high level of participation by the community is needed for success. We found that our sensitization meetings could be improved by giving more information on how the MDA works and finding means to generate small group discussions after the meeting.

Injuries and noncommunicable diseases: emerging health problems of children in developing countries

The present article identifies, for children living in developing countries, the major causes of ill-health that are inadequately covered by established health programmes. Injuries and noncommunicable diseases, notably asthma, epilepsy, dental caries, diabetes mellitus and rheumatic heart disease, are growing in significance. In countries where resources are scarce it is to be expected that increasing importance will be attached to the development and implementation of measures against these problems. Their control may benefit from the application of elements of programmes directed against infectious, nutritional and perinatal disorders, which continue to predominate.

Household contact study of Bordetella pertussis infections

Household contacts of primary pertussis cases were evaluated. Infection was determined by culture, direct fluorescent antibody assay, and serological criteria. Agglutinin titers and values of ELISA IgG and IgA antibodies to lymphocytosis-promoting factor, filamentous hemagglutinin, and pertactin were determined. In 39 households 255 subjects were exposed; 114 remained well (group 1), 53 had mild illness (group 2), and 88 had pertussis (group 3). The infection rates were 46% (group 1), 43% (group 2), and 80% (group 3). In a subgroup of subjects seen within 14-28 days of exposure, it was found that none with clinical pertussis had a value of IgG antibody to pertactin in acute-phase sera of > or = 50 ELISA units (EU) per mL or an agglutinin titer of > 256. Of the primary cases, 53% were > or = 13 years of age. These data point out the importance of Bordetella pertussis infections in adolescents and adults as a source of infection in young children. Our subgroup data suggest that high values of antibody to pertactin and high agglutinin titers may be predictive of protection against clinical pertussis.

Infectious disease considerations in pediatric organ transplantation

Infections are a major cause of morbidity and mortality after organ transplantation in children. Immunosuppression, surgery, and invasive devices all predispose to infection. A comprehensive pretransplantation evaluation can minimize risks and help anticipate special problems. Appropriate anti-microbial coverage during the perioperative period decreases the risk of infection. Bacteria and fungi are the major causes of infections occurring in the first month after transplantation. The site of infection during this period varies by organ transplanted: liver recipients often have intraabdominal infections, kidney recipients are predisposed to urinary tract infections and perinephric abscesses, and heart recipients often have respiratory tract or sternal wound infections. Viruses play a major role in infections occurring more than 1 month after transplantation, with cytomegalovirus the most significant agent. Other viruses of concern include herpes simplex virus, varicella-zoster virus, several common respiratory viruses, and Epstein-Barr virus with associated lymphoproliferative disorders. Tuberculosis, toxoplasmosis, and Pneumocystis pneumonia also occur later. Appropriate immunization and antimicrobial prophylaxis can help prevent infectious complications after transplantation.