PIIVeC Technical Vector Control Advisory Group Meeting, 4th and 5th December 2018

The first annual PIIVeC’s TVCAG meeting in Cameroon was held at the Monastère Notre Dame des Bénédictins of the Mont Fébé in Yaoundé, from the 4th to the 5th December 2018. Feedback from various participants indicate that it has been a very successful meeting.

Stakeholders from various Ministers (Public Health, Scientific Research, Agriculture and Livestock’s), research centres, universities and NGOs (VESTERGAARD, CPAC..), involved in vector-borne diseases control, have successfully being brought together. Many of them appreciated the PIIVeC initiative, took advantage to establish contacts and advocated for the sustainability of the initiative. The Ministry of Public Health stakeholders were fully involved with the opening and closing ceremonies done respectively by the Director of operational Research and the Director of Health promotion, and a session chaired by the Deputy Director of Disease Control. Also, Permanent secretaries in charge of malaria, filariasis, trypanosomiasis and Leishmaniasis programs attended the meeting.

During discussions following the presentation of Cameroon’s situation on vector-borne diseases by national control programs and the leading researchers of the field, it came out that Malaria national control program was the only one with funding (although external fund) and which achieved important milestones. However, it was not exempt of challenges. For example, during the last two nationwide campaigns of bed net distribution, the national research evidences on Anopheles resistance to the main insecticides (Pyrethroid, Carbamate and organochloride) have not been considered. For the up-coming 2019 LLIN campaign, the permanent secretary in charge of malaria control program revealed that the next insecticide to be used for mosquito bed nets will depend on results of ongoing research trials of many available combinations. Human African Trypanosomiasis (HAT) control is still based on case detection and treatment strategy whereas vector control using screens to push away tsetse flies is used in African Animal Trypanosomiasis (AAT) control program in northern Cameroon. Additional vector control could help achieving elimination of HAT but both programs do not unfortunately communicate. For Leishmaniasis, a lot need to be done, both on the parasites, vectors and reservoirs. There is no strategy to fight against sand-flies in the country. In fact, there is no knowledge about the diversity of this vector in the country despite the description of both cutaneous and visceral leishmaniasis in different regions. Schistosomiasis control program is still only based on chemotherapy although WHO has recommended additional vector control using Nicodamid molluscicide. Distribution map of gastropod vectors and compatibility level of some secondary hosts are still to be established. Onchocerciasis control rely mainly on Mass Drug Administration (MDA) of (Mectizan). However, some locations are still hyperendemic after 15 years of MDA. Moreover, the situation is worse where Onchocerca volvulus is co-endemic with Loa loa, the African eye worm. In this case, due to life-threatening side effects associated to ivermectin administration, the strategy is to first count loa loa microfilaremia and then treat only low microfilaremia intensity subjects. No control strategy is implemented against Simulium and Chrysops flies, and existing species are still to be identified in onchocerciasis hot spots. Lymphatic filariasis control program in Cameroon, based on Albendazole MDA, has shown positive results. Actually, of 137 old foci, only one is currently active (Akwaya, South West region) and the remaining (136) are on post-MDA surveillance. The LF parasites are transmitted by Anopheles and Culex mosquitoes. Thus, vector control of this disease takes advantages of all the malaria vector control tools as LLIN distribution campaign and Indoor residual spraying. No control program specifically targeting arboviral diseases is carried out in Cameroon. The main control scheme is the compulsory immunization of children under 5 years against yellow fever. Human disease recognition is mainly through case detection or retrospective studies. Research on Aedes mosquitoes have been put in place for species identification, geographical distribution and insecticide resistance profile characterization. However, nothing is known about the other arbovirus vectors such as ticks and biting midges as well as their implication in human and animal diseases.

At the end of the meeting, Cameroon data on vector-borne diseases were reviewed, activities to initiate or to strengthen identified, operational research projects listed and prioritized. it was clear that the TVCAG was an opportunity to create links/connection between the current national control programs both between themselves and with the national researchers to align the national health priorities to the research activities. In fact, there is a lack of communication between researchers and the policy makers which does not allow evidence-driven decisions of the health policy. Additionally, the communication between the national control programmes could result in integrated vector control strategies where applicable, especially for the diseases which share the same vectors.