The challenge of improving boiling: lessons learned from a randomized controlled trial of water pasteurization and safe storage in Peru.

Boiling is the most common method of household water treatment in developing countries; however, it is not always effectively practised. We conducted a randomized controlled trial among 210 households to assess the effectiveness of water pasteurization and safe-storage interventions in reducing Escherichia coli contamination of household drinking water in a water-boiling population in rural Peru. Households were randomized to receive either a safe-storage container or a safe-storage container plus water pasteurization indicator or to a control group. During a 13-week follow-up period, households that received a safe-storage container and water pasteurization indicator did not have a significantly different prevalence of stored drinking-water contamination relative to the control group [prevalence ratio (PR) 1·18, 95% confidence interval (CI) 0·92-1·52]. Similarly, receipt of a safe-storage container alone had no effect on prevalence of contamination (PR 1·02, 95% CI 0·79-1·31). Although use of water pasteurization indicators and locally available storage containers did not increase the safety of household drinking water in this study, future research could illuminate factors that facilitate the effective use of these interventions to improve water quality and reduce the risk of waterborne disease in populations that boil drinking water.

Underutilization of pneumococcal vaccine in nursing home in Washington State: report of a serotype-specific outbreak and a survey.

PURPOSE: To describe an outbreak of pneumococcal disease in a Washington state nursing home and to report a survey of pneumococcal vaccine utilization in Washington nursing homes. PATIENTS AND METHODS: Outbreak. Data were collected from nursing home residents' records. Nasopharyngeal cultures were obtained from residents and staff. Survey. Fifty-four randomly selected Washington nursing homes were surveyed about pneumococcal vaccine utilization and policies. RESULTS: Outbreak. Three confirmed and 4 possible cases of pneumococcal disease occurred over 9 days among 94 residents; 5 patients (71%) died. Cases were identified among 6 of 42 residents on 1 wing, compared with 1 of 52 on the other 2 wings (relative risk 7.4, 95% confidence interval 1.0, 398.5). Streptococcus pneumoniae serotype 9V was cultured from the blood of 3 confirmed case-patients and the nasopharynx of 2 of 73 residents. Only 7% of residents had received pneumococcal vaccine, including one case-patient who had received 14-valent vaccine without serotype 9V. Survey. Only 22% of residents were reported to have received pneumococcal vaccine; vaccination status was unknown for 66%. Physician discretion determined pneumococcal vaccination in 49 (91%) nursing homes; 9 (17%) had a written policy. Two major barriers to pneumococcal vaccination were cited: low priority among physicians (43%) and difficulty in determining residents' vaccine history (37%). CONCLUSIONS: A pneumococcal disease outbreak among undervaccinated nursing home residents probably resulted from person-to-person transmission. Pneumococcal vaccine appears to be underutilized in Washington state nursing homes.

Are there national risk factors for epidemic cholera? The correlation between socioeconomic and demographic indices and cholera incidence in Latin America.

BACKGROUND: From 1991 through 1995, all Latin American countries maintained cholera surveillance systems to track the epidemic that entered the region through Peru in January 1991. These data were used to assess correlations between socioeconomic and demographic indices that might serve as national risk predictors for epidemic cholera in Latin America. METHODS: Correlations between country-specific cumulative cholera incidence rates from 1991 through 1995 and infant mortality, the Human Development Index [HDI] a numerical value based on life expectancy, education, and income), gross national product (GNP) per capita, and female literacy were tested using the Pearson correlation coefficient. RESULTS: A total of 1,339,834 cholera cases with a cumulative incidence rate of 183 per 100,000 population were reported from affected Western Hemisphere countries from 1991 through 1995. Infant mortality rates were the most strongly correlated with cumulative cholera incidence based on the Pearson correlation coefficient. The HDI had a less strong negative correlation with cumulative cholera incidence. The GNP per capita and female literacy rates were weakly and negatively correlated with cholera cumulative incidence rates. CONCLUSIONS: Infant mortality and possibly the HDI may be useful indirect indices of the risk of sustained transmission of cholera within a Latin American country. Cumulative cholera incidence is decreased particularly in countries with infant mortality below 40 per 1000 live births. The lack of reported cholera cases in Uruguay and the Caribbean may reflect a low risk for ongoing transmission, consistent with socioeconomic and demographic indices. Cholera surveillance remains an important instrument for determining cholera trends within individual countries and regions.

PIP: To track a cholera epidemic that entered Latin America through Peru in January 1991, the region maintained cholera surveillance systems from 1991 through 1995. The present study used the surveillance data to identify socioeconomic and demographic indices that might serve as national risk predictors for epidemic cholera in Latin America. A total of 1,339,834 cholera cases, with a cumulative incidence rate of 183/100,000 population, were reported in 1991-95 from 22 countries in the region. Use of the Pearson correlation coefficient indicated that infant mortality rates were most strongly associated with cumulative cholera incidence. Cumulative cholera incidence was decreased in countries with an infant mortality below 40/1000 live births. The Human Development Index had a less strong negative correlation with cholera incidence, but values under 0.720 may provide an additional estimator of risk. The gross national product per capita (above US$2000) and female literacy rates above 90% were weakly and negatively correlated with cholera cumulative incidence rates. The continued lack of cholera cases in the Caribbean, where most countries have socioeconomic and demographic indices that resemble the Latin American countries with lowest risk for cholera, provides tentative support for this framework.

Using a knowledge, attitudes and practices survey to supplement findings of an outbreak investigation: cholera prevention measures during the 1991 epidemic in Peru.

BACKGROUND: To assess the effectiveness of the cholera prevention activities of the Peruvian Ministry of Health, we conducted a knowledge, attitudes, and practices (KAP) survey in urban and rural Amazon communities during the cholera epidemic in 1991. METHODS: We surveyed heads of 67 urban and 61 rural households to determine diarrhoea rates, sources of cholera prevention information, and knowledge, attitudes, and practices regarding ten cholera prevention measures. RESULTS: Twenty-five per cent of 482 urban and 11% of 454 rural household members had diarrhoea during the first 3-4 months of the epidemic. Exposure to mass media education was greater in urban areas, and education through interpersonal communication was more prevalent in rural villages. Ninety-three per cent of rural and 67% of urban respondents believed they could prevent cholera. The mean numbers of correct responses to ten knowledge questions were 7.8 for urban and 8.2 for rural respondents. Practices lagged behind knowledge and attitudes (mean correct response to ten possible: urban 4.9, rural 4.6). Seventy-five per cent of respondents drank untreated water and 91% ate unwashed produce, both of which were identified as cholera risk factors in a concurrently conducted case-control study. CONCLUSIONS: The cholera prevention campaign successfully educated respondents, but did not cause many to adopt preventive behaviours. Direct interpersonal education by community-based personnel may enhance the likelihood of translating education into changes in health behaviours. Knowledge, attitudes, and practices surveys conducted with case-control studies during an epidemic can be an effective method of refining education/control programmes.

PIP: The authors conducted a knowledge, attitudes, and practices (KAP) survey in urban and rural Amazon communities during the 1991 cholera epidemic to assess the effectiveness of the Peruvian Ministry of Health's cholera prevention activities. Diarrhea rates, sources of cholera prevention information, and knowledge, attitudes, and practices regarding 10 cholera prevention measures were determined by surveying the heads of 67 urban and 61 rural households. 25% of 482 urban and 11% of 454 rural household members had diarrhea during the first 3-4 months of the epidemic. Exposure to mass media education was greater in urban areas, while education through interpersonal communication prevailed in rural villages. 93% of rural and 67% of urban respondents believed they could prevent cholera. Rural respondents were slightly more knowledgeable than urban respondents about cholera. Overall, however, practices did not reflect their knowledge and attitudes; 75% of respondents drank untreated water and 91% ate unwashed produce.

Epidemic cholera in the Amazon: the challenge of preventing death.

Epidemic cholera struck Peru in January 1991, and spread rapidly. The national cholera case-fatality rate (CFR) was less than 1% in the first six months of the epidemic, but in some rural areas, the CFR exceeded 10%. We investigated cholera mortality in the rural Amazon region, an area with a CFR of 6.3%. We conducted a case-control study, comparing 29 decedents with 61 survivors of recent cholera-like diarrheal illness in 12 villages with a combined CFR of 13.5%. Of 29 decedents, 28 (96%) died in the village or en route to a health facility. Death occurred within 36 hours of illness onset for 83% of the decedents. In 11 (92%) villages, the first or second recognized case was fatal. Death was associated with receiving treatment only at home (odds ratio indeterminate; 95% confidence interval 3.5, indeterminate). Treatment with oral rehydration salts (ORS) was not protective against death for patients who received treatment only at home. Treatment with homemade sugar-salt solution (SSS) was also not protective; fewer than one-third of respondents knew the correct SSS recipe. Most decedents experienced multiple barriers to health care. Cholera victims died rapidly and early in village outbreaks, and few patients had access to health care. Provision of threatened villages with ORS supplies and education in their use before cholera strikes is essential to reducing cholera mortality in this region.

Narrow-mouthed water storage vessels and in situ chlorination in a Bolivian community: a simple method to improve drinking water quality.

Epidemiologic investigations of the Latin America cholera epidemic have repeatedly implicated untreated drinking water and water touched by hands during storage as important vehicles for disease transmission. To prevent such transmission, we provided a new narrow-mouthed, plastic, water storage vessel and 5% calcium hypochlorite solution for home disinfection of stored water to a Bolivian Aymara Indian community at risk for cholera. We evaluated acceptance of this intervention and its effect on water quality. Each of 42 families in the study obtained water from a household well; fecal coliform bacteria were found in water from 39 (93%) of 42 wells and 33 (79%) of 42 usual water storage vessels. One group of families received the special vessels and chlorine (group A), a second received only the special vessels (group B), and a third served as a control group (group C). Water samples collected every three weeks from group A special vessels had lower geometric mean fecal coliform colony counts (P < 0.0001) and lower geometric mean Escherichia coli colony counts (P < 0.0001) than water from group B or C vessels. Adequate levels of free chlorine persisted in these vessels for at least 5 hr. The special vessels and chlorine solution were well accepted and continued to be used for at least six months. Use of the vessel and chlorine solution produced drinking water from nonpotable sources that met World Health Organization standards for microbiologic quality.

Diarrhoea prevention in a high-risk rural Kenyan population through point-of-use chlorination, safe water storage, sanitation, and rainwater harvesting.

Lack of access to safe water and sanitation contributes to diarrhoea moribidity and mortality in developing countries. We evaluated the impact of household water treatment, latrines, shallow wells, and rainwater harvesting on diarrhoea incidence in rural Kenyan children. We compared diarrhoea rates in 960 children aged <5 years in 556 households in 12 randomly selected intervention villages and six randomly selected comparison villages during weekly home visits over an 8-week period. On multivariate analysis, chlorinating stored water [relative risk (RR) 0.44, 95% confidence interval (CI) 0.28-0.69], latrine presence (RR 0.71, 95% CI 0.54-0.92), rainwater use (RR 0.70, 95% CI 0.52-0.95), and living in an intervention village (RR 0.31, 95% CI 0.23-0.41), were independently associated with lower diarrhoea risk. Diarrhoea risk was higher among shallow well users (RR 1.78, 95% CI 1.12-2.83). Chlorinating stored water, latrines, and rainwater use all decreased diarrhoea risk; combined interventions may have increased health impact.

Epidemic cholera in urban Zambia: hand soap and dried fish as protective factors.

Between 28 November 2003 and 23 February 2004, 4343 cases and 154 deaths from cholera (case-fatality rate 3.5%) were reported in Lusaka, Zambia. A case-control study was conducted in February 2004 to assess potential transmission routes and prevention strategies. Consumption of raw vegetables was significantly associated with cholera [adjusted odds ratio (aOR) 4.7, 95% confidence interval (CI) 1.7-13, P=0.003). Consumption of a local sardine-like fish was protective (aOR 0.3, 95% CI 0.1-0.7, P=0.008). Hand soap was present in 90% of control homes and 58% of case homes. Observed hand soap was a strongly protective factor (aOR 0.1, 95% CI 0.04-0.4, P=0.001). No water source or treatment practice was significantly associated with cholera. This study documents the importance of foodborne transmission of cholera, illustrates the protective role of hand washing in an epidemic setting, and identifies a novel possible protective factor, a local fish, which warrants further research.

Adoption of safe water behaviors in Zambia: comparing educational and motivational approaches.

CONTEXT: In the developing world, drinking water is an important route for transmission of diarrheal disease, a leading cause of morbidity and mortality in children. OBJECTIVES: In Field Trial 1 (FT1) and Field Trial 2 (FT2), the effectiveness of the behavior change approach known as motivational interviewing (MI) was compared to the standard practice of health education alone in initiating and sustaining safe water treatment and storage behavior among community residents. In Field Trial 3 (FT3), MI was compared with social marketing. DESIGN: Community surveys were conducted prior to local health promoter training and at follow-up. SETTING AND PARTICIPANTS: Low socioeconomic status peri-urban communities in Zambia were project sites. Local volunteer health promoters from communities were trained in an adaptation of MI for safe water treatment and storage. INTERVENTIONS: All health promoters received instruction in the causes and prevention of diarrhea. Health promoters in the experimental (MI) groups received MI training. MAIN OUTCOME MEASURES: FT1 and FT3 measured detectable disinfectant levels in stored household water. FT2 measured disinfectant sales. FINDINGS: No significant differences between the treatment groups were found in FT1. Subsequent MI training incorporated lessons learned from the previous trial and resulted in much higher purchase rates of the disinfectant (FT2) and levels of disinfectant in stored household water (FT3) in the MI group. CONCLUSION: MI appears promising for public health initiatives in the developing world. Further research to improve and refine the method is needed.

Impact of the safe water system on water quality in cyclone-affected communities in Madagascar.

Cyclone Hudah struck the northeastern coast of Madagascar in the spring of 2000. Over a 5-month period, 11 700 relief kits consisting of bottles of water disinfectant and foldable jerry cans were distributed to the affected population. Five months after the cyclone, a survey was conducted in 12 villages to determine the impact of these relief kits on water quality. Seventy-six percent of the surveyed households reported using jerry cans, and 65% reported using the disinfectant. Stored water in households using both products had significantly less microbiological contamination than stored water in other households. To improve the prospects for a sustainable intervention, the response plan for future disasters should incorporate a transition to recovery and development, including formative research into local customs, beliefs, and water handling habits, and funding support to initiate social marketing.

Challenges in implementing a point-of-use water quality intervention in rural Kenya.

To prevent diarrheal diseases in western Kenya, CARE Kenya initiated the Water, Sanitation, and Education for Health (WASEH) Project in 1998. The project targets 72 farming and fishing communities with a total population of 43 000. Although the WASEH Project facilitated construction of shallow wells and pit latrines, the water quality still needed improvement. Consequently, in 2001, CARE implemented the Safe Water System (which consists of point-of-use water treatment with sodium hypochlorite, safe storage, and behavior change techniques) within the already established WASEH infrastructure, using existing community organizations in combination with a social marketing approach that introduced affordable products. The project has resulted in adoption rates of 33.5% for chemical water treatment and 18.5% for clay pots modified for safe water storage.

Collaboration, cholera, and cyclones: a project to improve point-of-use water quality in Madagascar.

In November 1999, CARE Madagascar, Population Services International (PSI), and the Centers for Disease Control and Prevention (CDC) selected 30 poor communities in urban Antananarivo as the target population for launch of the Safe Water System. The system consists of behavior change techniques along with point-of-use treatment and safe storage of water. The project was launched in March 2000, ahead of schedule, because a cholera epidemic struck Madagascar in January. Because of the enormous demand created by the cholera epidemic and by 3 cyclones that followed in the next 3 months, the project grew to national scale in less than a year. The combination of community mobilization and social marketing resulted in increased demand for and use of the Safe Water System.

Epidemic cholera in rural El Salvador: risk factors in a region covered by a cholera prevention campaign.

In response to the Latin American cholera epidemic, El Salvador began a prevention programme in April 1991. The first case was confirmed in August, and 700 cases were reported within 3 months. A matched case-control study was conducted in rural La Libertad Department in November 1991. Illness was associated with eating cold cooked or raw seafood (odds ratio [OR] = 7.0; 95% confidence limits [CL] = 1.4, 35.0) and with drinking water outside the home (OR = 8.8; 95% CL = 1.7, 44.6). Assertion of knowledge about how to prevent cholera (OR = 0.2; 95% CL = 0.1, 0.8) and eating rice (OR = 0.2; 95% CL = 0.1, 0.8) were protective. More controls than patients regularly used soap (OR = 0.3; 95% CL = 0.1, 1.0). This study demonstrated three important points for cholera prevention: (1) seafood should be eaten cooked and hot; (2) populations at risk should be taught to treat household drinking water and to avoid drinking water outside the home unless it is known to be treated; and (3) education about hygiene can be an important tool in preventing cholera.

Diarrhoea prevention in Bolivia through point-of-use water treatment and safe storage: a promising new strategy.

A novel water quality intervention that consists of point-of-use water disinfection, safe storage and community education was field tested in Bolivia. A total of 127 households in two periurban communities were randomized into intervention and control groups, surveyed and the intervention was distributed. Monthly water quality testing and weekly diarrhoea surveillance were conducted. Over a 5-month period, intervention households had 44% fewer diarrhoea episodes than control households (P = 0.002). Infants < 1 year old (P = 0.05) and children 5-14 years old (P = 0.01) in intervention households had significantly less diarrhoea than control children. Campylobacter was less commonly isolated from intervention than control patients (P = 0.02). Stored water in intervention households was less contaminated with Escherichia coli than stored water in control households (P < 0.0001). Intervention households exhibited less E. coli contamination of stored water and less diarrhoea than control households. This promising new strategy may have broad applicability for waterborne disease prevention.

Epidemic cholera in the Amazon: the role of produce in disease risk and prevention.

Epidemic cholera struck Peru in January 1991 and spread within a month to the Amazon headwaters. A case-control study was done in the Amazonian city of Iquitos, Peru. Cholera-like illness was associated with eating unwashed fruits and vegetables (odds ratio [OR] = 8.0; 95% confidence limits [CL] = 2.2, 28.9) and drinking untreated water (OR = 2.9; 95% CL = 1.3, 6.4). Consumption of a drink made from toronja, a citrus fruit, was protective against illness (OR = 0.4; 95% CL = 0.2, 0.7). Illness was inversely associated with the quantity of toronja drink consumed (P < .01). Produce has not previously been convincingly documented as a risk factor for cholera; this study underscores the importance of washing produce before eating it. Acidic juices, such as toronja drink (pH 4.1), inhibit vibrio growth and may make contaminated water safer. Wild citrus fruits such as toronja are abundant, cheap, and popular in the Amazon region. Promoting the consumption of toronja drink may be a useful cholera prevention strategy in this region.

Cultivation and phylogenetic characterization of a newly recognized human pathogenic protozoan.

An intraerythrocytic protozoan (WA1) recently isolated from a patient in Washington State was shown to be morphologically identical to Babesia microti but biologically and genetically distinct. Continuous growth of WA1 was established in stationary erythrocyte cultures. Hybridization of a chemiluminescent Babesia-specific DNA probe to Southern blots of restriction enzyme-digested genomic DNA showed that WA1 could be distinguished from other Babesia species that were antigenically cross-reactive (Babesia gibsoni and babesial parasites from desert bighorn sheep, Ovis canadensis nelsoni) or known to infect humans (B. microti, Babesia divergens, and Babesia equi), or both. A 1436-bp portion of the nuclear small subunit rRNA gene of WA1 was sequenced and analyzed. Genetic distance analysis showed that WA1 is most closely related to the canine pathogen B. gibsoni and lies within a phylogenetic cluster with Theileria species and B. equi. The methodology described will be useful for improved diagnosis and identification of human protozoal pathogens.

Babesiosis in Washington State: a new species of Babesia?

OBJECTIVE: To characterize the etiologic agent (WA1) of the first reported case of babesiosis acquired in Washington State. DESIGN: Case report, and serologic, molecular, and epizootiologic studies. SETTING: South-central Washington State. PATIENT: A 41-year-old immunocompetent man with an intact spleen who developed a moderately severe case of babesiosis. MEASUREMENTS: Serum specimens from the patient were assayed by indirect immunofluorescent antibody (IFA) testing for reactivity with seven Babesia species and with WA1, which was propagated in hamsters inoculated with his blood. A Babesia-specific, ribosomal-DNA (rDNA) probe was hybridized to Southern blots of restriction-endonuclease-digested preparations of DNA from WA1, Babesia microti, and Babesia gibsoni. Serum specimens from 83 family members and neighbors were assayed for IFA reactivity with WA1 and B. microti. Small mammals and ticks were examined for Babesia infection. RESULTS: The patient's serum had very strong IFA reactivity with WA1, strong reactivity with B. gibsoni (which infects dogs), but only weak reactivity with B. microti. DNA hybridization patterns with the rDNA probe clearly differentiated WA1 from B. gibsoni and B. microti. Four of the patient's neighbors had IFA titers to WA1 of 256. The tick vector and animal reservoir of WA1 have not yet been identified, despite trapping 83 mammals and collecting 235 ticks. CONCLUSIONS: WA1 is morphologically indistinguishable but antigenically and genotypically distinct from B. microti. Some patients elsewhere who were assumed to have been infected with B. microti may have been infected with WA1. Improved serodiagnostic and molecular techniques are needed for characterizing Babesia species and elucidating the epidemiology of babesiosis, an emergent zoonosis.