Risk factors associated with failing pre-transmission assessment surveys (pre-TAS) in lymphatic filariasis elimination programs: Results of a multi-country analysis.

Achieving elimination of lymphatic filariasis (LF) as a public health problem requires a minimum of five effective rounds of mass drug administration (MDA) and demonstrating low prevalence in subsequent assessments. The first assessments recommended by the World Health Organization (WHO) are sentinel and spot-check sites-referred to as pre-transmission assessment surveys (pre-TAS)-in each implementation unit after MDA. If pre-TAS shows that prevalence in each site has been lowered to less than 1% microfilaremia or less than 2% antigenemia, the implementation unit conducts a TAS to determine whether MDA can be stopped. Failure to pass pre-TAS means that further rounds of MDA are required. This study aims to understand factors influencing pre-TAS results using existing programmatic data from 554 implementation units, of which 74 (13%) failed, in 13 countries. Secondary data analysis was completed using existing data from Bangladesh, Benin, Burkina Faso, Cameroon, Ghana, Haiti, Indonesia, Mali, Nepal, Niger, Sierra Leone, Tanzania, and Uganda. Additional covariate data were obtained from spatial raster data sets. Bivariate analysis and multilinear regression were performed to establish potential relationships between variables and the pre-TAS result. Higher baseline prevalence and lower elevation were significant in the regression model. Variables statistically significantly associated with failure (p-value ≤0.05) in the bivariate analyses included baseline prevalence at or above 5% or 10%, use of Filariasis Test Strips (FTS), primary vector of Culex, treatment with diethylcarbamazine-albendazole, higher elevation, higher population density, higher enhanced vegetation index (EVI), higher annual rainfall, and 6 or more rounds of MDA. This paper reports for the first time factors associated with pre-TAS results from a multi-country analysis. This information can help countries more effectively forecast program activities, such as the potential need for more rounds of MDA, and prioritize resources to ensure adequate coverage of all persons in areas at highest risk of failing pre-TAS

Analysis of Children's Perception of Triatomine Vectors of Chagas Disease through Drawings: Opportunities for Targeted Health Education

<div><p>Background</p><p>Chagas disease is a tropical parasitic disease affecting about 10 million people, mostly in the Americas, and transmitted mainly by triatomine bugs. Insect vector control with indoor residual insecticides and the promotion of housing improvement is the main control intervention. The success of such interventions relies on their acceptance and appropriation by communities, which depends on their knowledge and perceptions of both the disease and the vector. In this study, we investigated school-aged children's knowledge and perception on triatomine vectors and Chagas disease to further understand how communities view this vector and the disease in Yucatan, Mexico.</p><p>Methodology/Principal findings</p><p>We performed an analysis of children's drawings on the theme of triatomines and their house in several rural villages, to explore in an open-ended manner their views, understanding and misconceptions. A total of 261 drawings were collected from children ages 6–12 from four villages. We found that children are very familiar with triatomine vectors, and know very well many aspects of their biology and ecology, and in particular their blood-feeding habits. On the other hand, their drawings suggest that the role of triatomines as vectors of a chronic and severe cardiac disease is less understood, and the main perceived health threat appears limited to the bite itself, as previously observed in adults.</p><p>Conclusions/Significance</p><p>These results have important implications for the specific design of future education materials and campaigns, and for the promotion of the inclusion of children in raising Chagas disease awareness in these endemic communities.</p></div

Animal hosts of triatomines.

<p>Dogs and chicken were described as the most frequent feeding sources, although feeding was also depicted for a variety of other domestic animals, including cows, horses, cats, sheep or goat.</p

Examples of triatomine habitats.

<p>Triatomines were frequently depicted in trees, firewood, grass and yard fence walls made of piled rocks. They were also depicted in chicken coops and other animal corrals, as well as next to lights in a few cases.</p

Examples of tratomine descriptions.

<p>The photograph shows <i>Triatoma dimidiata</i> from the region as adult male (right) and a 4^th and 2^nd stage nymphs (left). Cropped details of bugs from children's drawing ranged from detailed and accurate representations to indistinguishable bugs, some of which included nymphal stages.</p

Examples of drawings.

<p>Examples of drawings.</p

Perceptions of Chagas disease.

<p>The most frequently represented threat posed by triatomines was the bite wound, which was frequently depicted in the drawings. Some subjects also appeared to be sad or crying while been bitten. Triatomines were often depicted with warning sings and texts saying “Stop”, “Be carefull”, “If you see it, kill it”. However, triatomines were rarely associated with a chronic disease, and even less frequently with a cardiac disease. The happy heart says “If you want to see me happy, keep me away from the <i>pic</i>”.</p

Comparison among drawings from the different villages.

<p>The percentage of drawings with the indicated specific features is shown for each village. *, ** and *** indicate significant differences among the four villages (χ² tests, <i>P</i><0.05, <i>P</i><0.01, and <i>P</i><0.001, respectively).</p

Humans as a feeding source for triatomines.

<p>Many children described triatomines feeding on humans, very often while sleeping or resting in their bed or hammock. Triatomines were occasionally depicted flying toward a sleeping person to feed.</p

Contextual determinants of mass drug administration performance: Modelling fourteen years of lymphatic filariasis treatments in West Africa.

BackgroundEffective mass drug administration (MDA) is the cornerstone in the elimination of lymphatic filariasis (LF) and a critical component in combatting all neglected tropical diseases for which preventative chemotherapy is recommended (PC-NTDs). Despite its importance, MDA coverage, however defined, is rarely investigated systematically across time and geography. Most commonly, investigations into coverage react to unsatisfactory outcomes and tend to focus on a single year and health district. Such investigations omit more macro-level influences including sociological, environmental, and programmatic factors. The USAID NTD database contains measures of performance from thousands of district-level LF MDA campaigns across 14 years and 10 West African countries. Specifically, performance was measured as an MDA's epidemiological coverage, calculated as persons treated divided by persons at risk. This analysis aims to explain MDA coverage across time and geography in West Africa using sociological, environmental, and programmatic factors.MethodologyThe analysis links epidemiological coverage data from 3,880 LF MDAs with contextual, non-NTD data via location (each MDA was specific to a health district) and time (MDA month, year). Contextual data included rainfall, temperature, violence or social unrest, COVID-19, the 2014 Ebola outbreak, road access/isolation, population density, observance of Ramadan, and the number of previously completed MDAs.Principal findingsWe fit a hierarchical linear regression model with coverage as the dependent variable and performed sensitivity analyses to confirm the selection of the explanatory factors. Above average rainfall, COVID-19, Ebola, violence and social unrest were all significantly associated with lower coverage. Years of prior experience in a district and above average temperature were significantly associated with higher coverage.Conclusions/significanceThese generalized and context-focused findings supplement current literature on coverage dynamics and MDA performance. Findings may be used to quantify typically anecdotal considerations in MDA planning. The model and methodology are offered as a tool for further investigation