Impact of 19 years of mass drug administration with ivermectin on epilepsy burden in a hyperendemic onchocerciasis area in Cameroon.

Charlotte Boullé (1) , Alfred K. Njamnshi (2) , Fidèle Dema , Michel Karngong Mengnjo , Joseph Nelson Siewe Fodjo , Anne‑cécile Zoung‑kanyi Bissek (2) , Patrick Suykerbuyk , Cédric G. Lenou‑nanga , Hugues C Nana-Djeunga , Joseph Kamgno (2) , Cedric B. Chesnais (1) , Michel Boussinesq (1) , Robert Colebunders

1 TransVIHMI - Recherches Translationnelles sur le VIH et les maladies infectieuses endémiques et émergentes
2 University of Yaoundé [Cameroun]

BACKGROUND : Surveys conducted in 1991-1992 in the Mbam Valley (Cameroon) revealed that onchocerciasis was highly endemic, with community microfilarial loads (CMFL) > 100 microfilariae/snip in some villages. Also in 1991-1992, a survey of suspected cases of epilepsy (SCE) found 746 SCE using a questionnaire administered to individuals identified by key informants, with prevalences reaching 13.6% in some communities. From 1998, annual community-directed treatment with ivermectin (CDTI) was implemented to control onchocerciasis. In 2017, a door-to-door household survey was conducted in three of the villages visited in 1991-1992, using a standardized 5-item epilepsy screening questionnaire. RESULTS : In 2017, a total of 2286 individuals living in 324 households were screened (582 in Bayomen, 553 in Ngongol and 1151 in Nyamongo) and 112 SCE were identified (4.9%). Neurologists examined 92 of these SCE and confirmed the diagnosis of epilepsy for 81 of them (3.5%). Between the surveys in 1991-1992 and 2017, the prevalence of SCE decreased from 13.6% to 2.5% in Bayomen (P = 0.001), from 8.7% to 6.6% in Ngongol (P = 0.205) and from 6.4% to 5.4% in Nyamongo (P = 0.282). The median age of SCE shifted from 20 (IQR: 12-23) to 29 years (IQR: 18-33; P = 0.018) in Bayomen, from 16 (IQR: 12-21) to 26 years (IQR: 21-39; P < 0.001) in Ngongol and from 16 (IQR: 13-19) to 24 years (IQR: 19-32; P < 0.001) in Nyamongo. The proportions of SCE aged < 10, 10-19, 20-29 and ≥ 30 years shifted from 9.5, 58.3, 25.0 and 7.1% in 1991-1992 to 2.7, 20.5, 39.3 and 37.5% in 2017, respectively. CONCLUSIONS : SCE prevalence decreased overall between 1991-1992 and 2017. The age shift observed is probably due to a decrease in the number of new cases of epilepsy resulting from the dramatic reduction of Onchocerca volvulus transmission after 19 years of CDTI.

Mots clés: Cameroon; Epilepsy; Onchocerciasis; Community study

Domaines: Sciences du Vivant [q-bio]; Médicaments; Neurosciences [q-bio.NC]

Charlotte Boullé, Alfred K. Njamnshi, Fidèle Dema, Michel Karngong Mengnjo, Joseph Nelson Siewe Fodjo, et al.. Impact of 19 years of mass drug administration with ivermectin on epilepsy burden in a hyperendemic onchocerciasis area in Cameroon.. Parasites & Vectors, 2019, 12 (1), ⟨10.1186/s13071-019-3345-7⟩. ⟨hal-02458167⟩