Population movement: a key factor in the epidemiology of neglected tropical diseases.

This review provides an overview of the complex ways in which population movements are linked to spread and control of neglected tropical diseases ­ often exacerbated by insufficient medical services and sanitary infrastructure. A new typology of population movements is suggested which builds on previous work but offers a more comprehensive typology based on the variables of 'onset', 'cause', 'direction' and 'motivation'. Schistosomiasis and leishmaniasis provide examples of the intricate ways in which population movements may play a role. A thorough and context-specific understanding of these patterns combined with the ability and will to launch targeted public health interventions is needed to achieve adequate control of neglected tropical diseases as well as other infectious diseases.

Effect of preventive supplementation with ready-to-use therapeutic food on the nutritional status, mortality, and morbidity of children aged 6 to 60 months in Niger: a cluster randomized trial.

CONTEXT: Ready-to-use therapeutic foods (RUTFs) are an important component of effective outpatient treatment of severe wasting. However, their effectiveness in the population-based prevention of moderate and severe wasting has not been evaluated. OBJECTIVE: To evaluate the effect of a 3-month distribution of RUTF on the nutritional status, mortality, and morbidity of children aged 6 to 60 months in Niger. DESIGN, SETTING, AND PARTICIPANTS: A cluster randomized trial of 12 villages in Maradi, Niger. Six villages were randomized to intervention and 6 to no intervention. All children in the study villages aged 6 to 60 months were eligible for recruitment. INTERVENTION: Children with weight-for-height 80% or more of the National Center for Health Statistics reference median in the 6 intervention villages received a monthly distribution of 1 packet per day of RUTF (92 g [500 kcal/d]) from August to October 2006. Children in the 6 nonintervention villages received no preventive supplementation. Active surveillance for conditions requiring medical or nutritional treatment was conducted monthly in all 12 study villages from August 2006 to March 2007. MAIN OUTCOME MEASURES: Changes in weight-for-height z score (WHZ) according to the World Health Organization Child Growth Standards and incidence of wasting (WHZ <-2) over 8 months of follow-up. RESULTS: The number of children with height and weight measurements in August, October, December, and February was 3166, 3110, 2936, and 3026, respectively. The WHZ difference between the intervention and nonintervention groups was -0.10 z (95% confidence interval [CI], -0.23 to 0.03) at baseline and 0.12 z (95% CI, 0.02 to 0.21) after 8 months of follow-up. The adjusted effect of the intervention on WHZ from baseline to the end of follow-up was thus 0.22 z (95% CI, 0.13 to 0.30). The absolute rate of wasting and severe wasting, respectively, was 0.17 events per child-year (140 events/841 child-years) and 0.03 events per child-year (29 events/943 child-years) in the intervention villages, compared with 0.26 events per child-year (233 events/895 child-years) and 0.07 events per child-year (71 events/1029 child-years) in the nonintervention villages. The intervention thus resulted in a 36% (95% CI, 17% to 50%; P < .001) reduction in the incidence of wasting and a 58% (95% CI, 43% to 68%; P < .001) reduction in the incidence of severe wasting. There was no reduction in mortality, with a mortality rate of 0.007 deaths per child-year (7 deaths/986 child-years) in the intervention villages and 0.016 deaths per child-year (18 deaths/1099 child-years) in the nonintervention villages (adjusted hazard ratio, 0.51; 95% CI, 0.25 to 1.05). CONCLUSION: Short-term supplementation of nonmalnourished children with RUTF reduced the decline in WHZ and the incidence of wasting and severe wasting over 8 months. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00682708.

Risk factors for visceral Leishmaniasis among residents and migrants in Kafta-Humera, Ethiopia.

BACKGROUND: Visceral leishmaniasis is a lethal parasitic disease transmitted by phlebotomine sand flies. The largest focus of VL in Ethiopia is located in the lowland region bordering Sudan, where the epidemiology is complicated by the presence of thousands of seasonal agricultural workers who live under precarious conditions. METHODOLOGY/PRINCIPAL FINDINGS: We conducted two parallel case-control studies to identify factors associated with VL risk in residents and migrants. The studies were conducted from 2009 to 2011 and included 151 resident cases and 157 migrant cases, with 2 matched controls per case. In multivariable conditional regression models, sleeping under an acacia tree at night (odds ratios (OR) 5.2 [95% confidence interval 1.7-16.4] for residents and 4.7 [1.9-12.0] for migrants), indicators of poverty and lower educational status were associated with increased risk in both populations. Strong protective effects were observed for bed net use (OR 0.24 [0.12-0.48] for net use in the rainy season among residents, OR 0.20 [0.10-0.42] for any net use among migrants). For residents, living in a house with thatch walls conferred 5-fold and sleeping on the ground 3-fold increased risk. Among migrants, the risk associated with HIV status was borderline significant and sleeping near dogs was associated with 7-fold increased risk. CONCLUSIONS/SIGNIFICANCE: Preventive strategies should focus on ways to ensure net usage, especially among migrant workers without fixed shelters. More research is needed to understand migration patterns of seasonal labourers and vector bionomics.

Reducing wasting in young children with preventive supplementation: a cohort study in Niger.

OBJECTIVE: To compare the incidence of wasting, stunting, and mortality among children aged 6 to 36 months who are receiving preventive supplementation with either ready-to-use supplementary foods (RUSFs) or ready-to-use therapeutic foods (RUTFs). SUBJECTS AND METHODS: Children aged 6 to 36 months in 12 villages of Maradi, Niger, (n = 1645) received a monthly distribution of RUSFs (247 kcal [3 spoons] per day) for 6 months or RUTFs (500-kcal sachet per day) for 4 months. We compared the incidence of wasting, stunting, and mortality among children who received preventive supplementation with RUSFs versus RUTFs. RESULTS: The effectiveness of RUSF supplementation depended on receipt of a previous preventive intervention. In villages in which a preventive supplementation program was previously implemented, the RUSF strategy was associated with a 46% (95% confidence interval [CI]: 6%-69%) and 59% (95% CI: 17%-80%) reduction in wasting and severe wasting, respectively. In contrast, in villages in which the previous intervention was not implemented, we found no difference in the incidence of wasting or severe wasting according to type of supplementation. Compared with the RUTF strategy, the RUSF strategy was associated with a 19% (95% CI: 0%-34%) reduction in stunting overall. CONCLUSION: We found that the relative performance of a 6-month RUSF supplementation strategy versus a 4-month RUTF strategy varied with receipt of a previous nutritional intervention. Contextual factors will continue to be important in determining the dose and duration of supplementation that will be most effective, acceptable, and sustainable for a given setting.

Risk factors for visceral leishmaniasis in a new epidemic site in Amhara Region, Ethiopia.

We conducted a case-control study to evaluate risk factors for visceral leishmaniasis during an epidemic in a previously unaffected district of Ethiopia. We also collected blood and bone marrow specimens from dogs in the outbreak villages. In multivariable analyses of 171 matched case-control pairs, dog ownership, sleeping under an acacia tree during the day, and habitually sleeping outside at night were associated with significantly increased risk. Specimens from 7 (3.8%) dogs were positive by immunofluorescent antibody test (IFAT) and both enzyme-linked immunosorbent assays (ELISAs), whereas Leishmania DNA was detected in 5 (2.8%) bone marrow aspirates (from 3 seropositive and 2 seronegative dogs). Insecticide-treated nets may only protect a portion of those at risk. Further research on the vectors, the role of the dog in the transmission cycle, and the effect of candidate interventions are needed to design the best strategy for control.

Nonantiretroviral drug consumption by CD4 cell count in HIV-infected adults: a 5-year cohort study in Côte d'Ivoire.

We followed a cohort of 592 HIV-infected adults during 1292 person-years in Abidjan before the highly active antiretroviral therapy (HAART) era. On the basis of the exhaustive monitoring of nonantiretroviral drugs actually delivered to the patients and of the real cost of drugs at the cohort center's pharmacy during the study period, we estimated the mean cost of drugs per person per year (MCPPY) overall, by drug characteristics, and by patients' baseline CD4 cell count. The MCPPY was dollar 198 US overall and dolalr 83 US, dollar 101 US, dollar 186 US, dollar 233 US, and dollar 459 US in patients with a baseline CD4 count > or = 500 cells/mm, 350 to 499 cells/mm, 200 to 349 cells/mm, 100 to 199 cells/mm, and <100 cells/mm, respectively. The most costly classes of drugs were the antibacterial (MCPPY dollar 30 US), the antifungal (dollar 16 US), and the analgesic (dollar 6 US) classes in patients with a baseline CD4 count > or = 500 cells/mm versus the antifungal (dollar 208 US), the antibacterial (dollar 49 US), and the antiparasitic (dollar 31 US) classes in patients with a baseline CD4 count <100 cells/mm. These data could be used in further cost-effectiveness analyses that seek to prioritize health interventions. Meanwhile, they roughly suggest that successful antiretroviral treatment, which would stabilize the CD4 count above 500 cells/mm, could reduce by 5-fold the cost of nonantiretroviral drugs in HIV-infected adults in Abidjan.