Performance of Pit Latrines and Their Herd Protection Against Diarrhea: A Longitudinal Cohort Study in Rural Ethiopia.

In sanitation policies, "improved sanitation" is often broadly described as a goal with little rationale for the minimum standard required. We conducted a secondary analysis of data collected as part of a cluster randomized controlled trial in rural Ethiopia. We compared the performance of well-constructed and poorly constructed pit latrines in reducing child diarrhea. In addition, we explored whether having a well-constructed household latrine provides indirect protection to neighbors if cluster-level coverage reaches a certain threshold. We followed up children aged younger than 5 years (U5C) of 906 households in rural areas of the Gurage zone, Ethiopia, for 10 months after community-led total sanitation interventions. A study-improved latrine was defined as having all the following: pit of ≥2 m depth, slab of any material, drop-hole cover, wall, roof, door, and handwashing facilities (water and soap observed). U5C in households with a study-improved latrine had 54% lower odds of contracting diarrhea than those living in households with a latrine missing 1 or more of the characteristics (adjusted odds ratio [aOR]=0.46; 95% confidence interval [CI]=0.27, 0.81; P=.006). Analyses were adjusted for child age and sex, presence of improved water for drinking, and self-reported handwashing at 4 critical times. The odds of having diarrhea among those with an improved latrine based on the World Health Organization/UNICEF Joint Monitoring Program (JMP) definition (i.e., pit latrines with slabs) were not substantially different from those with a JMP-unimproved latrine (aOR=0.99; 95% CI=0.56, 1.79; P=.99). Of U5C living in households without a latrine or with a study-unimproved latrine, those in the high-coverage villages were less likely to contract diarrhea than those in low-coverage villages (aOR=0.55; 95% CI=0.35, 0.86; P=.008). We recommend that academic studies and routine program monitoring and evaluation should measure more latrine characteristics and evaluate multiple latrine categories instead of making binary comparisons only.

Effect of a Homestead Food Production Program on the Prevalence of Diarrhea and Acute Respiratory Infection in Children in Sylhet, Bangladesh: A Cluster-Randomized Controlled Trial.

Diarrhea and respiratory illness are leading causes of mortality and morbidity among young children. We assessed the impact of a homestead food production intervention on diarrhea and acute respiratory infection (ARI) in children in Bangladesh, secondary outcomes of the Food and Agricultural Approaches to Reducing Malnutrition (FAARM) cluster-randomized trial. The trial enrolled 2,705 married women and their children 3 years or younger in 96 rural settlements (geographic clusters) in Sylhet Division, Bangladesh. The intervention promoted home gardening and poultry rearing alongside child nutrition and health counseling over 3 years (2015-2018). An 8-month food hygiene behavior change component using emotional drivers was delivered beginning in mid-2017. Caregiver-reported diarrhea and symptoms of ARI in the week preceding the survey were recorded every 2 months. We analyzed 32,460 observations of 3,276 children over 4 years and found that 3.9% of children had diarrhea and 3.4% had an ARI in the prior 7 days. There was no overall effect of the intervention on 7-day diarrhea period prevalence (odds ratio [OR], 0.92; 95% CI, 0.71-1.19), diarrhea point prevalence (OR, 1.03; 95% CI, 0.78-1.36), or 7-day ARI period prevalence (OR, 1.18; 95% CI, 0.88-1.60). There was no impact on diarrhea severity or differences in health-seeking behaviors. Our findings suggest that this homestead food production program was insufficient to reduce morbidity symptoms among children in a rural setting. More comprehensive water, sanitation, and hygiene measures, and behavioral recommendations may be needed to achieve impacts on child health.

The effect of improving solid waste collection on waste disposal behaviour and exposure to environmental risk factors in urban low-income communities in Pakistan.

OBJECTIVE: To estimate the effect of improving waste collection services on waste disposal behaviour and exposure to environmental risk factors in urban, low-income communities in Pakistan. METHODS: We enrolled six low-income communities in Islamabad (Pakistan), four of which received an intervention consisting of a door-to-door low-cost waste collection service with centralised waste processing and recycling sites. Intervention communities underwent community-level and household-level mobilisation. The effect of the intervention on waste disposal behaviour, exposure to waste and synanthropic fly counts was measured using two cross-sectional surveys in 180 households per community. RESULTS: Intervention communities had less favourable socio-economic indicators and poorer access to waste disposal services at baseline than control communities. Use of any waste collection service increased from 5% to 49% in the intervention communities (difference 44%, 95% CI 41%, 48%), but the increase was largely confined to two communities where post-intervention coverage exceeded 80% and 90%, respectively. An increase in the use of waste collection services was also found in the two control communities (from 21% to 67%, difference 47%, 95% CI 41%, 53%). Fly counts decreased by about 60% in the intervention communities (rate ratio 0.4, 95% CI 0.3, 0.4) but not in the control communities (rate ratio 1.52, 95% CI 1.1, 2.2). The decrease in fly counts was largely confined to the two high-coverage intervention communities. CONCLUSION: Introduction of a low-cost waste collection service has the potential for high uptake in low-income communities and for decreasing the exposure to waste and synanthropic flies at household level. Intervention success was constrained by low uptake in half of the intervention communities.

The incidence of Orientia tsutsugamushi infection in rural South India.

Scrub typhus is a common bacterial infection in Asia caused by Orientia tsutsugamushi. This serological cohort study estimated the incidence of infection in a rural population in South India. Participants were enrolled through systematic sampling in 46 villages at baseline, and revisited the following year. Blood samples were tested for IgG antibodies using ELISA, followed by indirect immunofluorescence assays (IFA) in those positive for ELISA at both rounds. A case was defined as sero-conversion (ELISA), or at least a 4-fold titre increase (IFA), between the two time points. In addition to crude incidence rate estimates, we used piecewise linear rates across calendar months, with rates proportional to the monthly incidence of local hospital cases to address seasonality and unequal follow-up times. Of 402 participants, 61.7% were female. The mean age was 46.7 years, (range 13-88). 21 participants showed evidence for serological infection. The estimated incidence was 4.4 per 100 person-years (95% CI 2.8-6.7). The piecewise linear rates approach resulted in a similar estimate of 4.6 per 100 person years (95% CI 2.9-6.9). Considering previous estimates of symptomatic scrub typhus incidence in the same study population, only about 2-5% of infections may result in clinically relevant disease.

Effects of Menstrual Health and Hygiene on School Absenteeism and Drop-Out among Adolescent Girls in Rural Gambia.

Poor knowledge and management of menstruation impacts girls' school attendance and academic performance. This paper aims to explore how menstrual hygiene management practices and related factors influence school absenteeism and drop-out among primary and secondary school girls in rural Gambia. Mixed-method studies were conducted among students and key informants from 19 schools from July 2015-December 2017. Focus group discussions, in-depth interviews, cross-sectional surveys, menstrual diaries, and school water, sanitation and hygiene (WASH) facility observations were used. Key findings from the interviews were that menstrual pain, cultural beliefs, fear of peers knowing menstrual status, and poor school WASH facilities led to school absenteeism, however, they had no impact on school drop-out. Of the 561 girls surveyed, 27% reported missing at least one school day per month due to menses. Missing school during the most recent menstrual period was strongly associated with menstrual pain (extreme pain adjusted odds ratio (AOR) = 16.8 (95% CI: 7.29-38.74)), as was having at least one symptom suggestive of urinary tract infection (AOR = 1.71 (95% CI: 1.16-2.52)) or reproductive tract infection (AOR = 1.99 (95% CI: 1.34-2.94)). Clean toilets (AOR = 0.44 (95% CI: 0.26-75)), being happy using school latrines while menstruating (AOR = 0.59 (95% CI: 0.37-0.93)), and soap availability (AOR = 0.46 (95% CI: 0.3-0.73)) were associated with reduced odds of school absenteeism. This study suggests menstrual pain, school WASH facilities, urogenital infections, and cultural beliefs affected school attendance among menstruating girls in rural Gambia.

Agreement and error of titration assays.

Titration assays can be used to define positivity either in terms of a change over time, i.e. seroconversion, or relative to a fixed threshold. The operating characteristics of these definitions depend on the precision of the assay. We present methods for estimating the distribution of errors, at the level of a single replicate, from the distribution of within-pair agreement. When the maximum replicate-level error is one dilution, a simple probability argument is used, with estimation by method of moments. For the more general case, a discretized Gaussian model is used, with maximumum likelihood estimation. These models fit well to eight published datasets. The discretized Gaussian model also allows the potential performance of alternative dilution factors to be assessed. For influenza hemagglutination-inhibition, the approach is compared to a previous Markov chain Monte Carlo data augmentation model. These methods allow the estimation of the underlying error distribution from observed between-replicate differences under repeatability conditions. The results can be used to guide the choice of the fold change necessary to infer seroconversion. Finer dilution factors, e.g. 1.5 rather than 2, could facilitate a better balance between the sensitivity and specificity of titration assays.

Clinical characteristics of and antibody response to spotted fever group rickettsial infections in South India: Case series and serological cohort study.

OBJECTIVE: The clinical and serological characteristics of spotted fever group rickettsial (SFGR) infections in South Asia are poorly understood. We studied the clinical presentation and the IgM/IgG response in cases enrolled at two health care centres in South India. METHOD: We enrolled 77 patients. Fifty-seven of these patients were recruited at a tertiary care centre, the remaining 20 at a community hospital (secondary care level). Diagnostic tests included IgM and IgG enzyme-linked immunosorbent assay and polymerase chain reaction. Over a period of 1 year, 41 cases were followed up for repeated sero-analysis. RESULTS: Median age was 9 years (range 1-79). A rash was present in 74% of cases (57/77). In cases aged <15 years, rash was present in 94% (44/47) vs. 43% (13/30) in cases aged ≥15 years. An eschar was found in two cases (3%). Severe infection or complications occurred in 10 cases (13%). These included central nervous system infection (6/77, 8%), kidney injury (3/77, 4%), shock (3/77, 4%), lung involvement (2/77, 3%) and peripheral gangrene (2/77, 3%). IgM antibody levels increased faster after fever onset than IgG antibodies, peaking at 50 and 60 days, respectively. After the peak, IgM and IgG levels showed a slow decline over one year with less than 50% of cases showing persistent IgG antibody levels. CONCLUSION: Spotted fever group rickettsial infections in South India may be under-diagnosed, as many cases may not develop a rash. The proportion of cases developing severe infection seems lower than for scrub typhus in this region. IgG seroprevalence may substantially underestimate the proportion in a population with past SFGR infection.

Effect of a Community-led Total Sanitation Intervention on the Incidence and Prevalence of Diarrhea in Children in Rural Ethiopia: A Cluster-randomized Controlled Trial.

We conducted a cluster-randomized trial in 48 rural villages of Ethiopia to assess the effect of community-led total sanitation (CLTS) on the diarrhea incidence of children. Twenty-four villages were randomly assigned to the intervention group and the other 24 were assigned to the control group. A CLTS intervention was implemented from January 2016 through January 2017. Baseline data collection was conducted during October and November 2015. At baseline, 906 children were recruited and followed-up until January 2017. These 906 children were randomly selected among all children in the 48 villages. To determine the 7-day period prevalence of diarrhea, four household-based surveys were conducted by independent data collectors at 3, 5, 9, and 10 months after the CLTS was initiated. To determine the incidence and longitudinal prevalence, the presence of daily diarrhea presence was recorded for 140 days using diary methods. The loss to follow-up rates were 95% for period prevalence and 93% for incidence and longitudinal prevalence. The incidence ratio and longitudinal prevalence ratio were 0.66 (95% confidence interval [CI], 0.45-0.97; P = 0.03) and 0.70 (95% CI, 0.52-0.95; P = 0.02) after adjusting for clustering and stratification. The relative risk of period prevalence was 0.66 (95% CI, 0.45-0.98; P = 0.04) at 3 months after initiation. Improved toilet coverage increased from 0.0% at baseline to 35.0% at 10 months in the intervention villages, whereas it increased from 0.7% to 2.8% in the control villages. Adherence to the intervention was comparable with that of previous studies; therefore, we suggest that the findings of this study are replicable.

Identifying Targets for the Prevention of Childhood Undernutrition in a Resource-Limited Peri-Urban Ecuadorian Community.

BACKGROUND: In middle-income countries, malnutrition concentrates in marginalized populations with a lack of effective preventive strategies. OBJECTIVE: Identify risk factors for undernutrition in a peri-urban Ecuadorian community of children aged 12 to 59 months. METHODS: Data from a cross-sectional survey in 2011 of children 1 to 5 years were analyzed including demographic data, medical history and examination, food frequency questionnaire (FFQ), anthropometric measurements, and blood for complete blood count, C-reactive protein, vitamin A, iron, and zinc levels. Dietary Diversity Score (DDS) was calculated from FFQ. Bivariate and multivariate analysis assessed effects on primary outcome of undernutrition by DDS, vitamin deficiencies, and demographic and nutritional data. RESULTS: N = 67, 52.2% undernourished: 49.3% stunted, 25.4% underweight, and 3% wasted; 74.6% (n = 50) were anemic and 95.1% (n = 39) had low serum zinc. Dietary Diversity Score was universally low (mean 4.91 ± 1.36, max 12). Undernutrition was associated with lower vitamin A levels (20 306, IQR: 16605.25-23973.75 vs 23665, IQR: 19292-26474 ng/mL, P = .04); underweight was associated with less parental report of illness (43.8%, n = 7 vs 80% n = 40, P = .005) and higher white blood count (13.7, IQR: 11.95-15.8 vs 10.9, IQR: 7.8-14.23 × 109/L, P = .02). In multiple regression, risk of undernutrition decreased by 4% for every $10 monthly income increase (95 CI%: 0.5%-7.4%, P = .02, n = 23); risk of underweight decreased by 0.06 for every increased DDS point (adjusted odds ratio: 0.06; 95 CI%: 0.004-0.91, P = .04, n = 23). CONCLUSIONS: In this peri-urban limited-resource, mostly Indigenous Ecuadorian community, stunting exceeds national prevalence, lower monthly income is the strongest predictor of undernutrition, lower DDS can predict some forms of undernutrition, and vitamin deficiencies are associated with but not predictive of undernutrition.

Effects of an urban sanitation intervention on childhood enteric infection and diarrhea in Maputo, Mozambique: A controlled before-and-after trial.

We conducted a controlled before-and-after trial to evaluate the impact of an onsite urban sanitation intervention on the prevalence of enteric infection, soil transmitted helminth re-infection, and diarrhea among children in Maputo, Mozambique. A non-governmental organization replaced existing poor-quality latrines with pour-flush toilets with septic tanks serving household clusters. We enrolled children aged 1-48 months at baseline and measured outcomes before and 12 and 24 months after the intervention, with concurrent measurement among children in a comparable control arm. Despite nearly exclusive use, we found no evidence that intervention affected the prevalence of any measured outcome after 12 or 24 months of exposure. Among children born into study sites after intervention, we observed a reduced prevalence of Trichuris and Shigella infection relative to the same age group at baseline (<2 years old). Protection from birth may be important to reduce exposure to and infection with enteric pathogens in this setting.

High initial IgG antibody levels against Orientia tsutsugamushi are associated with an increased risk of severe scrub typhus infection.

BACKGROUND: Scrub typhus is a dominant cause of febrile illness in many parts of Asia. Immunity is limited by the great strain diversity of Orientia tsutsugamushi. It is unclear whether previous infection protects from severe infection or enhances the risk. METHODS/PRINCIPAL FINDINGS: We studied IgG antibody levels against O. tsutsugamushi at presentation in 636 scrub typhus patients using enzyme-linked immunosorbent assays (ELISA). The association between ELISA optical density (OD) and risk of severe infection was modelled using Poisson regression. OD was categorised as low (<1.0), intermediate (1.0 to 2.9), and high (≥3.0). OD was also modelled as a continuous variable (cubic spline). Median age of cases was 41 years (range 0-85), with 37% having severe infection. Compared to the low category, the age-adjusted risk of severe infection was 1.5 times higher in the intermediate category (95%CI 1.2, 1.9), and 1.3 times higher in the high category (95%CI 1.0, 1.7). The effect was stronger in cases <40 years, doubling the risk in the intermediate and high categories compared to the low category. The effect was more pronounced in cases tested within 7 days of fever onset when IgG ODs are more likely to reflect pre-infection levels. CONCLUSIONS/SIGNIFICANCE: Intermediate and high IgG antibody levels at the time of diagnosis are associated with a higher risk of severe scrub typhus infection. The findings may be explained by severe infection eliciting an accelerated IgG response or by previous scrub typhus infection enhancing the severity of subsequent episodes.

Menstrual hygiene management practices and associated health outcomes among school-going adolescents in rural Gambia.

Inadequate menstrual hygiene management (MHM) practices have been associated with adverse health outcomes. This study aimed to describe MHM practices among schoolgirls from rural Gambia and assess risk factors associated with urogenital infections and depressive symptoms. A cross-sectional study was conducted among adolescent schoolgirls in thirteen schools in rural Gambia. A questionnaire was used to collect information on socio-demographics, MHM practices and clinical symptoms of reproductive and urinary tract infections (UTIs). A modified Beck Depression Inventory-II was used to screen for depressive symptoms. Mid-stream urine samples were collected to assess for UTIs. Modified Poisson regression analysis was used to determine risk factors for symptoms of urogenital infections and depression among adolescent girls. Three hundred and fifty-eight girls were recruited. Although, 63% of the girls attended schools providing free disposable pads, reusable cloths/towels were the commonest absorbent materials used. Heavy menstrual bleeding was associated with depressive symptoms (adjusted prevalence ratio, aPR 1.4 [95% CI 1.0, 1.9]), while extreme menstrual pain (aPR 1.3 [95% CI 1.2, 1,4]), accessing sanitary pads in school (aPR 1.4 [95% CI 1.2, 1.5]) and less access to functional water source at school (aPR 1.4 [95% CI 1.3, 1.6]) were associated with UTI symptoms. Conversely, privacy in school toilets (aPR 0.6 [95% CI 0.5, 0.7]) was protective for UTI symptoms. Heavy menstrual bleeding (aPR 1.4 [95% CI 1.1, 2.0]) and taking <30 minutes to collect water at home were associated with RTI symptoms (aPR 1.2 [95% CI 1.0, 1.5]) while availability of soap in school toilets (aPR 0.6 [95% CI 0.5, 0.8] was protective for RTI symptoms. Interventions to ensure that schoolgirls have access to private sanitation facilities with water and soap both at school and at home could reduce UTI and RTI symptoms. More attention is also needed to support girls with heavy menstrual bleeding and pain symptoms.

Cluster-randomised trial to test the effect of a behaviour change intervention on toilet use in rural India: results and methodological considerations.

BACKGROUND: Effective and scalable behaviour change interventions to increase use of existing toilets in low income settings are under debate. We tested the effect of a novel intervention, the '5 Star Toilet' campaign, on toilet use among households owning a toilet in a rural setting in the Indian state of Gujarat. METHODS: The intervention included innovative and digitally enabled campaign components delivered over 2 days, promoting the upgrading of existing toilets to achieve use by all household members. The intervention was tested in a cluster randomised trial in 94 villages (47 intervention and 47 control). The primary outcome was the proportion of households with use of toilets by all household members, measured through self- or proxy-reported toilet use. We applied a separate questionnaire tool that masked open defecation questions as a physical activity study, and excluded households surveyed at baseline from the post-intervention survey. We calculated prevalence differences using linear regression with generalised estimating equations. RESULTS: The primary study outcome was assessed in 2483 households (1275 intervention and 1208 control). Exposure to the intervention was low. Post-intervention, toilet use was 83.8% in the control and 90.0% in the intervention arm (unadjusted difference + 6.3%, 95%CI 1.1, 11.4, adjusted difference + 5.0%, 95%CI -0.1, 10.1. The physical activity questionnaire was done in 4736 individuals (2483 intervention and 2253 control), and found no evidence for an effect (toilet use 80.7% vs 82.2%, difference + 1.7%, 95%CI -3.2, 6.7). In the intervention arm, toilet use measured with the main questionnaire was higher in those exposed to the campaign compared to the unexposed (+ 7.0%, 95%CI 2.2%, 11.7%), while there was no difference when measured with the physical activity questionnaire (+ 0.9%, 95%CI -3.7%, 5.5%). Process evaluation suggested that insufficient campaign intensity may have contributed to the low impact of the intervention. CONCLUSION: The study highlights the challenge in achieving high intervention intensity in settings where the proportion of the total population that are potential beneficiaries is small. Responder bias may be minimised by masking open defecation questions as a physical activity study. Over-reporting of toilet use may be further reduced by avoiding repeated surveys in the same households. TRIAL REGISTRATION: The trial was registered on the RIDIE registry ( RIDIE-STUDY-ID-5b8568ac80c30 , 27-8-2018) and retrospectively on clinicaltrials.gov ( NCT04526171 , 30-8-2020).

Risk Factors for Scrub Typhus, Murine Typhus, and Spotted Fever Seropositivity in Urban Areas, Rural Plains, and Peri-Forest Hill Villages in South India: A Cross-Sectional Study.

Scrub typhus and spotted fever group rickettsioses are thought to be common causes of febrile illness in India, whereas they rarely test for murine typhus. This cross-sectional study explored the risk factors associated with scrub typhus, tick-borne spotted fever, and murine typhus seropositivity in three different geographical settings, urban, rural, and hill villages in Tamil Nadu, South India. We enrolled 1,353 participants living in 48 clusters. The study included a questionnaire survey and blood sampling. Blood was tested for Orientia tsutsugamushi (scrub typhus), Rickettsia typhi (murine typhus), and spotted fever group Rickettsia IgG using ELISA. The seroprevalence of scrub typhus, spotted fever, and murine typhus were 20.4%, 10.4%, and 5.4%, respectively. Scrub typhus had the highest prevalence in rural areas (28.1%), and spotted fever was most common in peri-forested areas (14.9%). Murine typhus was more common in rural (8.7%) than urban areas (5.4%) and absent in peri-forested hill areas. Agricultural workers had a higher relative risk for scrub typhus, especially in urban areas. For murine typhus, proximity to a waterbody and owning a dog were found to be major risk factors. The main risk factors for spotted fever were agricultural work and living in proximity to a forest. Urban, rural plains, and hill settings display distinct epidemiological pattern of Orientia and rickettsial infections. Although scrub typhus and spotted fever were associated with known risk factors in this study, the findings suggest a different ecology of murine typhus transmission compared with other studies conducted in Asia.

Antibody response following scrub typhus infection: clinical cohort study.

OBJECTIVE: Scrub typhus is a common cause of fever in Asia. The antibody response to infection and its effect on subsequent infection are unclear. We studied the IgM and IgG antibody response after infection, accounting for clinical severity. METHOD: We studied 197 scrub typhus patients for up to 2 years post-infection. Overall, 501 blood samples were analysed for scrub typhus antibodies using ELISA. IgM and IgG ELISA optical densities (OD) were analysed using quantile regression. OD values of 1.0 (IgM) and 1.5 (IgG) were used to define seropositivity. RESULTS: IgM OD values fell rapidly from an initial peak after infection. 50% of cases were IgM seronegative after 82 days. About 2 years after fever onset, 50% of cases had fitted IgG OD values of <1.5. Patients with high initial IgG OD values (≥2.5, used as a proxy for probable previous scrub typhus infection) had a more sustained IgG response than those with a low initial IgG OD, and more often presented with complications (18/36 = 50% vs. 28/91 = 30.8%, risk ratio = 1.63, 95% CI 1.04, 2.55, P = 0.035). This association was robust to adjusting for age (risk ratio 1.50, 95% CI 0.96, 2.33, P = 0.072). CONCLUSION: Cross-sectional IgG seroprevalence data substantially underestimate the proportion in a population ever infected with scrub typhus. A high initial IgG as a potential marker for previous scrub typhus infection may be associated with long-term IgG persistence and a higher risk of complicated scrub typhus.

OBJECTIF: Le typhus exfoliant est une cause fréquente de fièvre en Asie. La réponse anticorps à l'infection et son effet sur l'infection ultérieure ne sont pas clairs. Nous avons étudié la réponse des anticorps IgM et IgG après infection, en tenant compte de la sévérité clinique. MÉTHODE: Nous avons étudié 197 patients atteints de typhus exfoliant pendant une période allant jusqu'à deux ans après l'infection. Au total, 501 échantillons de sang ont été analysés pour déterminer la présence d'anticorps anti-typhus à l'aide d'ELISA. Les densités optiques (DO) des ELISA d'IgM et d'IgG ont été analysées par régression quantile. Les valeurs de DO de 1,0 (IgM) et 1,5 (IgG) ont été utilisées pour définir la séropositivité. RÉSULTATS: Les valeurs de DO d'IgM ont rapidement diminué par rapport au pic initial après infection. 50% des cas étaient séronégatifs pour les IgM après 82 jours. Environ 2 ans après le début de la fièvre, 50% des cas avaient des valeurs ajustées de OD d'IgG inférieures à 1,5. Les patients présentant des valeurs initiales de DO d'IgG élevées (≥2,5, utilisés comme proxy d'une infection antérieure probable par le typhus exfoliant) présentaient une réponse IgG plus maintenue que ceux présentant une DO initiale d'IgG faible et présentaient plus souvent des complications (18/36 = 50% vs. 28/91 = 30,8%, rapport de risque: 1,63; IC95%: 1,04-2,55, P = 0,035). Cette association était robuste pour l'ajustement en fonction de l'âge (rapport de risque: 1,50; IC95%: 0,96-2,33, P = 0,072). CONCLUSION: Les données transversales sur la séroprévalence des IgG sous-estiment considérablement la proportion dans une population déjà infectée par le typhus exfoliant. Des IgG initialement élevées en tant que marqueur potentiel d'infection antérieure par le typhus exfoliant peuvent être associées à une persistance à long terme des IgG et à un risque plus élevé de typhus exfoliant compliqué.

Hospitalisations and outpatient visits for undifferentiated fever attributable to scrub typhus in rural South India: Retrospective cohort and nested case-control study.

BACKGROUND: The burden of scrub typhus in endemic areas is poorly understood. This study aimed at estimating the proportion of hospitalisations and outpatient visits for undifferentiated fever in the community that may be attributable to scrub typhus. METHODOLOGY AND PRINCIPAL FINDINGS: The study was a retrospective cohort with a nested case-control study conducted in the South Indian state of Tamil Nadu. We conducted house-to-house screening in 48 villages (42965 people, 11964 households) to identify hospitalised or outpatient cases due to undifferentiated fever during the preceding scrub typhus season. We used scrub typhus IgG to determine past infection. We calculated adjusted odds ratios for the association between IgG positivity and case status. Odds ratios were used to estimate population attributable fractions (PAF) indicating the proportion of hospitalised and outpatient fever cases attributable to scrub typhus. We identified 58 cases of hospitalisation and 236 outpatient treatments. 562 people were enrolled as control group to estimate the background IgG sero-prevalence. IgG prevalence was 20.3% in controls, 26.3% in outpatient cases and 43.1% in hospitalised cases. The PAFs suggested that 29.5% of hospitalisations and 6.1% of outpatient cases may have been due to scrub typhus. In villages with a high IgG prevalence (defined as ≥15% among controls), the corresponding PAFs were 43.4% for hospitalisations and 5.6% for outpatients. The estimated annual incidence of scrub typhus was 0.8/1000 people (0.3/1000 in low, and 1.3/1000 in high prevalence villages). Evidence for recall error suggested that the true incidences may be about twice as high as these figures. CONCLUSIONS: The study suggests scrub typhus as an important cause for febrile hospitalisations in the community. The results confirm the adequacy of empirical treatment for scrub typhus in hospitalised cases with undifferentiated fever. Since scrub typhus may be rare among stable outpatients, the use of empirical treatment remains doubtful in these.

Comparing trap designs and methods for assessing density of synanthropic flies in Odisha, India.

BACKGROUND: There are many different traps available for studying fly populations. The aim of this study was to find the most suitable trap to collect synanthropic fly populations to assess the impact of increased latrine coverage in the state of Odisha, India. METHODS: Different baits were assessed for use in sticky pot traps (60% sucrose solution, 60 g dry sucrose, half a tomato and an non-baited control), followed by different colours of trap (blue versus yellow) and finally different types of trap (baited sticky pot trap versus sticky card traps). The experiments were undertaken in a semi-urban slum area of Bhubaneswar, the capital of Odisha. The first experiment was conducted in 16 households over 30 nights while experiments 2 and 3 were conducted in 5 households over 30 nights. RESULTS: The traps predominantly caught adult Musca domestica and M. sorbens (78.4, 62.6, 83.8% combined total in experiments 1-3 respectively). Non-baited traps did not catch more flies (median 7.0, interquartile range, IQR: 0.0-24.0) compared with baited traps (sucrose solution: 6.5, 1.0-27.0; dry sucrose: 5.0, 0.5-14.5; tomato: 5.0, 1.5-17.5). However, there were significantly more flies collected on blue sticky pot traps, which caught nearly three times as many flies as yellow sticky pot traps (Incidence Rate Ratio, IRR = 2.91; 95% CI: 1.77-4.79); P < 0.001). Sticky card traps (27, 8-58) collected significantly more flies than the non-baited sticky pot traps (10, 1.5-30.5). CONCLUSIONS: Blue sticky card traps can be recommended for the capture of synanthropic fly species as they are non-intrusive to residents, easy to use, readily allow for species identification, and collect sufficient quantities of flies over 12 hours for use in monitoring and control programmes.

Effect of Neighborhood Sanitation Coverage on Fecal Contamination of the Household Environment in Rural Bangladesh.

Enteric pathogens can be transmitted within the household and the surrounding neighborhood. The objective of this study was to understand the effect of neighborhood-level sanitation coverage on contamination of the household environment with levels of fecal indicator bacteria in rural Bangladesh. We conducted spot-check observations of sanitation facilities in neighboring households (NHs) within a 20-m radius of target households with children aged 6-24 months. Sanitation facilities were defined as improved (a private pit latrine with a slab or better) or unimproved. Fecal coliforms (FCs) on children's hands and sentinel toy balls were measured and used as indicators of household-level fecal contamination. We visited 1,784 NHs surrounding 428 target households. On average, sentinel toy balls had 2.11(standard deviation [SD] = 1.37) log10 colony-forming units (CFUs) of FCs/toy ball and children's hands had 2.23 (SD = 1.15) log10 CFU of FCs/two hands. Access to 100% private improved sanitation coverage in the neighborhood was associated with a small and statistically insignificant difference in contamination of sentinel toy balls (difference in means = -0.13 log10 CFU/toy ball; 95% confidence intervals [CI]: -0.64, 0.39; P = 0.63) and children's hands (difference in means = -0.11 log10 CFU/two hands; 95% CI: -0.53, 0.32; P = 0.62). Improved sanitation coverage in the neighborhood had limited measurable effect on FCs in the target household environment. Other factors such as access to improved sanitation in the household, absence of cow dung, presence of appropriate water drainage, and optimal handwashing practice may be more important in reducing FCs in the household environment.

Risk factors for childhood enteric infection in urban Maputo, Mozambique: A cross-sectional study.

BACKGROUND: Enteric infections are common where public health infrastructure is lacking. This study assesses risk factors for a range of enteric infections among children living in low-income, unplanned communities of urban Maputo, Mozambique. METHODS & FINDINGS: We conducted a cross-sectional survey in 17 neighborhoods of Maputo to assess the prevalence of reported diarrheal illness and laboratory-confirmed enteric infections in children. We collected stool from children aged 1-48 months, independent of reported symptoms, for molecular detection of 15 common enteric pathogens by multiplex RT-PCR. We also collected survey and observational data related to water, sanitation, and hygiene (WASH) characteristics; other environmental factors; and social, economic, and demographic covariates. We analyzed stool from 759 children living in 425 household clusters (compounds) representing a range of environmental conditions. We detected ≥1 enteric pathogens in stool from most children (86%, 95% confidence interval (CI): 84-89%) though diarrheal symptoms were only reported for 16% (95% CI: 13-19%) of children with enteric infections and 13% (95% CI: 11-15%) of all children. Prevalence of any enteric infection was positively associated with age and ranged from 71% (95% CI: 64-77%) in children 1-11 months to 96% (95% CI: 93-98%) in children 24-48 months. We found poor sanitary conditions, such as presence of feces or soiled diapers around the compound, to be associated with higher risk of protozoan infections. Certain latrine features, including drop-hole covers and latrine walls, and presence of a water tap on the compound grounds were associated with a lower risk of bacterial and protozoan infections. Any breastfeeding was also associated with reduced risk of infection. CONCLUSIONS: We found a high prevalence of enteric infections, primarily among children without diarrhea, and weak associations between bacterial and protozoan infections and environmental risk factors including WASH. Findings suggest that environmental health interventions to limit infections would need to be transformative given the high prevalence of enteric pathogen shedding and poor sanitary conditions observed. TRIAL REGISTRATION: ClinicalTrials.gov NCT02362932.

Effect of a School-Based Hygiene Behavior Change Campaign on Handwashing with Soap in Bihar, India: Cluster-Randomized Trial.

Changing hand hygiene behavior at scale in the community remains a challenge. The objective of this study was to estimate the effect of Unilever's school-based "School of 5" handwashing campaign on handwashing with soap (HWWS) in schoolchildren and their mothers in the Indian state of Bihar. We conducted a cluster-randomized trial in two districts. We randomized a total of 32 villages with at least one eligible school to intervention and control groups (1:1) and recruited 338 households in each group for outcome measurement. We used structured observation in households to measure HWWS at target occasions (after defecation, soap use during bathing, and before each main meal) in schoolchildren and their mothers. Observers were blinded to intervention status. We observed 636 target occasions (297 in the intervention arm and 339 in the control arm) in mothers and school-going children. After the intervention, HWWS prevalence at target occasions was 22.4% in the control arm and 26.6% in the intervention arm (prevalence difference +4.4%, 95% confidence interval: -4.0, 12.8). The difference was similar in children and mothers. Observers appeared to be adequately blinded to intervention status, whereas observed households were successfully kept unaware of the purpose of observations. To conclude, we found no evidence for a health-relevant effect of the School of 5 intervention on HWWS in schoolchildren and their mothers. Qualitative research suggested that reasons for the low impact of the intervention included low campaign intensity, ineffective delivery, and a model possibly not well tailored to these challenging physical and social environments.