Relationship between oral declaration on adherence to ivermectin treatment and parasitological indicators of onchocerciasis in an area of persistent transmission despite a decade of mass drug administration in Cameroon

BACKGROUND: Onchocerciasis control for years has been based on mass drug administration (MDA) with ivermectin (IVM). Adherence to IVM repeated treatment has recently been shown to be a confounding factor for onchocerciasis elimination precisely in rain forest areas where transmission continues and Loa loa co-exists with Onchocerca volvulus. In this study, participants’ oral declarations were used as proxy to determine the relationship between adherence to IVM treatment and parasitological indicators of onchocerciasis in the rain forest area of Cameroon with more than a decade of MDA. METHODS: Participants were recruited based on their IVM intake profile with the aid of a semi-structured questionnaire. Parasitological examinations (skin sniping and nodule palpation) were done on eligible candidates. Parasitological indicators were calculated and correlated to IVM intake profile. RESULTS: Of 2,364 people examined, 15.5 % had never taken IVM. The majority (40.4 %) had taken the drug 1–3 times while only 18 % had taken ≥ 7 times. Mf and nodule prevalence rates were still high at 47 %, 95 % CI [44.9–49.0 %] and 36.4 %, 95 % CI [34.4–38.3 %] respectively. There was a treatment-dependent reduction in microfilaria prevalence (r(s) =−0.986, P = 0.01) and intensity (r(s) =−0.96, P = 0.01). The highest mf prevalence (59.7 %) was found in the zero treatment group and the lowest (33.9 %) in the ≥ 7 times treatment group (OR = 2.8; 95 % CI [2.09–3.74]; P < 0.001). Adults with ≥ 7 times IVM intake were 2.99 times more likely to have individuals with no microfilaria compared to the zero treatment group (OR = 2.99; 95 % CI [2.19–4.08], P < 0.0001). There was no clear correlation between treatment and nodule prevalence and intensity. CONCLUSION: Adherence to ivermectin treatment is not adequate in this rain forest area where L. loa co-exists with O. volvulus. The prevalence and intensity of onchocerciasis remained high in individuals with zero IVM intake after more than a decade of MDA. Our findings show that using parasitological indicators, reduction in prevalence is IVM intake-dependent and that participants’ oral declaration of treatment adherence could be relied upon for impact studies. The findings are discussed in the context of challenges for the elimination of onchocerciasis in this rain forest area

Situation analysis of parasitological and entomological indices of onchocerciasis transmission in three drainage basins of the rain forest of South West Cameroon after a decade of ivermectin treatment

BACKGROUND: Community-Directed Treatment with Ivermectin (CDTI) is the main strategy adopted by the African Programme for Onchocerciasis control (APOC). Recent reports from onchocerciasis endemic areas of savannah zones have demonstrated the feasibility of disease elimination through CDTI. Such information is lacking in rain forest zones. In this study, we investigated the parasitological and entomological indices of onchocerciasis transmission in three drainage basins in the rain forest area of Cameroon [after over a decade of CDTI]. River basins differed in terms of river number and their flow rates; and were characterized by high pre-control prevalence rates (60-98%). METHODS: Nodule palpation and skin snipping were carried out in the study communities to determine the nodule rates, microfilarial prevalences and intensity. Simulium flies were caught at capture points and dissected to determine the biting, parous, infection and infective rates and the transmission potential. RESULTS: The highest mean microfilaria (mf) prevalence was recorded in the Meme (52.7%), followed by Mungo (41.0%) and Manyu drainage basin (33.0%). The same trend was seen with nodule prevalence between the drainage basins. Twenty-three (23/39) communities (among which 13 in the Meme) still had mf prevalence above 40%. All the communities surveyed had community microfilarial loads (CMFL) below 10 mf/skin snip (ss). The infection was more intense in the Mungo and Meme. The intensity of infection was still high in younger individuals and children less than 10 years of age. Transmission potentials as high as 1211.7 infective larvae/person/month were found in some of the study communities. Entomological indices followed the same trend as the parasitological indices in the three river basins with the Meme having the highest values. CONCLUSION: When compared with pre-control data, results of the present study show that after over a decade of CDTI, the burden of onchocerciasis has reduced. However, transmission is still going on in this study site where loiasis and onchocerciasis are co-endemic and where ecological factors strongly favour the onchocerciasis transmission. The possible reasons for this persistent and differential transmission despite over a decade of control efforts using ivermectin are discussed. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13071-015-0817-2) contains supplementary material, which is available to authorized users

Proceedings East, Central and Southern African Regional Workshop on Vitamin A interventions and child survival, Lusaka, Zambia, 21-24 June, 1990.

Vitamin A Technical Assistance Program (VITAP

Children aged 12–59 months missed through the National Vitamin A Capsule Distribution Program in Bangladesh: findings of the Nutritional Surveillance Project

From January 1990 to December 2006, Helen Keller International implemented the Nutritional Surveillance Project (NSP) in Bangladesh, which has been used to conduct regular surveillance and special surveys to provide information on health and nutritional status of children and mothers, and report on the coverage and impact of nutrition and health programs in Bangladesh. The Government of Bangladesh (GOB) distributes vitamin A Capsule (VAC) among children aged 12–59 months biannually. The NSP data was analyzed to assess VAC coverage and to explore which children were less likely to receive a VAC in order to help GOB identify necessary modifications aimed at higher coverage of VAC among all eligible children. Results showed that coverage among girls and boys was not different (P=0.970). However, coverage was consistently lower among children aged 12-23 months compared to older children (24–59 months) (P≤0.001) in each of the distribution rounds. Coverage among children from poorer households was lower than among children from wealthiest households (P&#60;0.001), with the extent of this difference varying by round. Coverage was significantly higher if households had had contact with a government health assistant in the last month (P&#60;0.001); and among households who owned a radio or a TV compared to those who did not. The VAC distribution campaign needs to be strengthened to cover the children who are currently not reached; especially younger children, children living in underserved regions, children from poorer households and from households with less contact with health service providers or mass media.<br>De janvier 1990 à décembre 2006, l’ONG Helen Keller International a mis en oeuvre le projet Nutritional Surveillance Project (NSP) au Bangladesh. Ce projet a permis de réaliser une surveillance régulière et des études ciblées afin de recueillir des informations sur l’état de santé et l’état nutritionnel des mères et des enfants, et de rendre compte de la couverture et de l’impact des programmes de nutrition et de santé au Bangladesh. Le gouvernement bangladais (GB) distribue, deux fois par an, une gélule de vitamine A (GVA) aux enfants de 12 à 59 mois. Les données du NSP ont été analysées pour estimer le taux de couverture de la GVA et déterminer les enfants les moins susceptibles de recevoir une GVA afin d’aider le GB à identifier les modifications nécessaires pour élargir la distribution de GVA à tous les enfants éligibles. Les résultats ont montré un taux de couverture identique chez les filles et les garçons (P=0,970). Le taux de couverture était invariablement plus faible chez les enfants de 12 à 23 mois que chez les enfants plus âgés (24–59 mois) (P≤0,001) dans chaque tournée de distribution. Le taux de couverture était plus faible chez les enfants des familles les plus pauvres que chez les enfants des familles les plus aisées (P&#60;0,001), l’ampleur de cette différence variant par tournée. Le taux de couverture était significativement plus élevé lorsque les familles avaient eu un contact avec un membre des services de santé du gouvernement au cours du mois précédent (P&#60;0,001) et dans les familles qui possédaient une radio ou un téléviseur comparé à celles qui n’en avaient pas. La campagne de distribution de la GVA doit être renforcée afin d’inclure les enfants qui ne le sont pas actuellement ; en particulier, les plus jeunes d’entre eux, les enfants qui vivent dans des régions mal desservies, les enfants des familles les plus pauvres et des familles ayant le moins de contact avec les prestataires de soin ou les médias de masse.<br>De enero de 1990 a diciembre de 2006 Helen Keller International llevó a cabo el Proyecto de Vigilancia Nutricional (PVN) en Bangladesh, que ha sido utilizado para realizar controles regulares e informes especiales sobre el estado nutricional y de salud de los niños y madres, así como la cobertura y el efecto conseguido por los programas nutricionales y sanitarios. El Gobierno distribuye semestralmente cápsulas de vitamina A entre los niños de entre 12 y 59 meses. Se han analizado los datos del PVN para evaluar la cobertura de las cápsulas y los niños con menor probabilidad de recibirlas con el fin de ayudar al gobierno a identificar las modificaciones necesarias para lograr una mayor cobertura. Los resultados obtenidos han demostrado que no hay diferencia entre sexos (P=0.970). Sin embargo, la cobertura es sistemáticamente menor entre los niños de entre 12 y 23 meses en comparación con los niños mayores (24–59 meses) (P≤0.001) en cada una de las fases de distribución. Asimismo, los niños pertenecientes a familias más pobres reciben menos cápsulas que los de familias más ricas (P&#60;0.001), aunque la diferencia varía entre las distintas fases realizadas. La cobertura es significativamente mayor si las familias han estado en contacto con un asistente sanitario gubernamental en el último mes (P&#60;0.001); y entre las familias que tienen radio o televisor frente a las que no tienen. La campaña de distribución de cápsulas debe reforzarse para acceder a los niños sin alcance, especialmente los niños de edades más tempranas, los que viven en zonas sin servicios, así como los de familias más pobres o con un contacto menor con el personal de servicios sanitarios o los medios de comunicación