Evaluation of onchocerciasis control in the Upper Denkyira East municipal in the forest area of Ghana: Responses of participants and distributors to the CDTI programme

The African Programme for Onchocerciasis Control (APOC), which focused on annual mass treatment with ivermectin, was launched in 1995 and was replaced by the Expanded Special Project for Neglected Tropical Diseases (ESPEN) by the end of 2015. In Ghana, the Community Directed Treatment with Ivermectin (CDTI) was introduced in 1999. After a decade, biannual reinforcement was introduced during which the Ghana Health Service (GHS) recorded coverage rates through routine data collection. Transmission studies conducted in the Upper Denkyira East Municipal (UDEM) of the forest zone of Ghana in 2002 and 2006 had shown that annual treatments with ivermectin had hardly any effect on the transmission of Onchocerca volvulus by the vector Simulium sanctipauli. In order to establish whether or not this was due to an insufficient compliance to the CDTI programme, an additional questionnaire survey was carried out in 2013 following those conducted in 2002 and 2006. The repeat transmission survey conducted in 2013 in the same area revealed that the vector S. sanctipauli had apparently disappeared from the rivers Ofin and Pra due to gold mining activities. In 2006 and 2013, we conducted surveys using structured questionnaires to address issues related to compliance and to compare re sults on the effectiveness of CDTI. A total of 692 individuals from 7 villages and 447 individuals from 9 villages were interviewed in 2006 and 2013 respectively. Questions asked included whether or not they had taken the ivermectin and reasons for not doing so when that was the case. Results were compared with the previous investigations conducted in 2002. Whereas official reported coverage rates ranged from 59 to 85% in 2006 and from 88 to 97% in 2013, compliance rates decreased from 36% in 2006 to 21% in 2013. Factors affecting compliance included fear of unpleasant side effects (pruritus and oedema), which decreased from 36% to 21% for the same period. Lack of awareness of CDTI sharply increased from 12% to 46% for the same period. Participants believed that treatments were no longer necessary due to the absence of vectors observed in 2013. There seems to be a considerable difference between coverage and compliance rates in the study communities. The difference can be attributed to the performance of the Community-Directed Distributors (CDDs) and the absence of the vector population observed in 2013. Discussions with CDDs suggested that factors that led to non compliance were mostly side effects, unawareness of the disease by immigrants and lack of financial motivation for the CDDs. Also included was the fact that they needed to complete distribution of the drugs in the entire village, covering all households within just one week irrespective of the size of the catchment area. This, they thought was too much work for a short period of time. We propose to intensify the training of CDDs by the national Neglected Tropical Diseases Programme (NTDP) and to include the Community-based Health and Planning Services (CHPS) concept into onchocerciasis control efforts for awareness creation while the vector population and the transmission should be further monitored. The population should be made aware that the side effects they experienced from previous treatments or had heard about had reduced significantly. They also should be in the known that vector flies may return and so the risk of transmission remains
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Acta Tropica 185 (2018) 357–362