N.M. Manga

The spatiotemporal evolution of human mobility and the related fluctuations of population density are known to be key drivers of the dynamics of infectious disease outbreaks. These factors are particularly relevant in the case of mass gatherings, which may act as hotspots of disease transmission and spread. Understanding these dynamics, however, is usually limited by the lack of accurate data, especially in developing countries. Mobile phone call data provide a new, first-order source of information that allows the tracking of the evolution of mobility fluxes with high resolution in space and time. Here, we analyze a dataset of mobile phone records of ∼150,000 users in Senegal to extract human mobility fluxes and directly incorporate them into a spatially explicit, dynamic epidemiological framework. Our model, which also takes into account other drivers of disease transmission such as rainfall, is applied to the 2005 cholera outbreak in Senegal, which totaled more than 30,000 reported cases. Our findings highlight the major influence that a mass gathering, which took place during the initial phase of the outbreak, had on the course of the epidemic. Such an effect could not be explained by classic, static approaches describing human mobility. Model results also show how concentrated efforts toward disease control in a transmission hotspot could have an important effect on the large-scale progression of an outbreak.

BACKGROUND: Food insecurity in sub-Saharan Africa and malnutrition constitute the main obstacles for successful treatment of people living with HIV/AIDS (PLWH). The aim of this study was to assess the effect of consuming daily 100 g RUTF (ready-to-use therapeutic food) as supplement, on body composition, anemia and zinc status of hospitalized PLWH in Senegal. METHODS: A Controlled clinical trial was conducted in 65 PLWH randomly allocated to receive either standard hospital diet alone (Control group: n = 33), or the standard diet supplemented with 100 g RUTF/day (RUTF group: n = 32). Supplementation was continued at home during 9 weeks. Individual dietary intakes were measured and compared to the Recommended Dietary Allowances. Body composition was determined using Bio-Impedance Analysis. Hemoglobin was measured by HemoCue and plasma zinc (PZ) concentration by atomic absorption spectrometry. PZ was adjusted to infection (CRP and α1-AGP). All measures were conducted on admission, discharge and after 9 weeks home-based follow up. RESULTS: 34 and 24% of the patients in RUTF and Control groups were suffering from severe malnutrition (BMI < 16 kg/m(2)), respectively. In both groups, more than 90% were anemic and zinc deficiency affected over 50% of the patients. Food consumed by the Control group represented 75, 14 and 55% of their daily recommended intake (DRI) of energy, iron and zinc, respectively. When 100 g of RUTF was consumed with the standard diet, the DRI of energy and zinc were 100% covered (2147 kcal, 10.4 mg, respectively), but not iron (2.9 mg). After 9 weeks of supplementation, body weight, and fat-free mass increased significantly by +11% (p = 0.033), and +11.8% (p = 0.033) in the RUTF group, but not in the Control group, while percentage body fat was comparable between groups (p = 0.888). In the RUTF group, fat free mass gain is higher in the patients on ART (+11.7%, n = 14; p = 0.0001) than in those without ART (+6.2%, n = 6; p = 0.032). Anemia decreased significantly with the supplementation, but zinc status, measured using plasma zinc concentration, remained unchanged. CONCLUSION: Improving PLWH' diet with 100 g RUTF for a long period has a positive impact on muscle mass and anemia but not on the zinc status of the patients. TRIAL NUMBER: NCT02433743, registered 29 April 2015.

Cholera is an acute diarrheal illness caused by Vibrio cholerae and occurs as widespread epidemics in Africa. In 2005, there were 31,719 cholera cases, with 458 deaths in the Republic of Senegal. We retrospectively investigated the climate origin of the devastating floods in mid-August 2005, in the Dakar Region of Senegal and the subsequent outbreak of cholera along with the pattern of cholera outbreaks in three other regions of that country. We compared rainfall patterns between 2002 and 2005 and the relationship between the sea surface temperature (SST) gradient in the tropical Atlantic Ocean and precipitation over Senegal for 2005. Results showed a specific pattern of rainfall throughout the Dakar region during August, 2005, and the associated rainfall anomaly coincided with an exacerbation of the cholera epidemic. Comparison of rainfall and epidemiological patterns revealed that the temporal dynamics of precipitation, which was abrupt and heavy, was presumably the determining factor. Analysis of the SST gradient showed that the Atlantic Ocean SST variability in 2005 differed from that of 2002 to 2004, a result of a prominent Atlantic meridional mode. The influence of this intense precipitation on cholera transmission over a densely populated and crowded region was detectable for both Dakar and Thiès, Senegal. Thus, high resolution rainfall forecasts at subseasonal time scales should provide a way forward for an early warning system in Africa for cholera and, thereby, trigger epidemic preparedness. Clearly, attention must be paid to both natural and human induced environmental factors to devise appropriate action to prevent cholera and other waterborne disease epidemics in the region.

The WHO guidelines for the management of advanced HIV disease recommend a package of care consisting of rapid initiation of antiretroviral therapy (ART), enhanced screening and diagnosis of tuberculosis (TB) and cryptococcal meningitis, co-trimoxazole prophylaxis, isoniazid preventive therapy (IPT), fluconazole pre-emptive therapy, and adherence support. The goals of this study were to determine the prevalence of advanced HIV disease among individuals initiating ART in Senegal, to identify predictors of advanced disease, and to evaluate adherence to the WHO guidelines. This study was conducted among HIV-positive individuals initiating ART in Dakar and Ziguinchor, Senegal. Clinical evaluations, laboratory analyses, questionnaires and chart review were conducted. Logistic regression was used to identify predictors of advanced disease. A total of 198 subjects were enrolled; 70% were female. The majority of subjects (71%) had advanced HIV disease, defined by the WHO as a CD4 count < 200 cells/mm3 or clinical stage 3 or 4. The median CD4 count was 185 cells/mm3. The strongest predictors of advanced disease were age ≥ 35 (OR 5.80, 95%CI 2.35–14.30) and having sought care from a traditional healer (OR 3.86, 95%CI 1.17–12.78). Approximately one third of subjects initiated ART within 7 days of diagnosis. Co-trimoxazole prophylaxis was provided to 65% of subjects with CD4 counts ≤350 cells/mm3 or stage 3 or 4 disease. TB symptom screening was available for 166 subjects; 54% reported TB symptoms. Among those with TB symptoms, 39% underwent diagnostic evaluation. Among those eligible for IPT, one subject received isoniazid. No subjects underwent CrAg screening or received fluconazole to prevent cryptococcal meningitis. This is the first study to report an association between seeking care from a traditional healer and presentation with WHO defined advanced disease in sub-Saharan Africa. Given the widespread use of traditional healers in sub-Saharan Africa, future studies to further explore this finding are indicated. Although the majority of individuals in this study presented with advanced disease and warranted management according to WHO guidelines, there were numerous missed opportunities to prevent HIV-associated morbidity and mortality. Programmatic evaluation is needed to identify barriers to implementation of the WHO guidelines and enhanced funding for operational research is indicated.