Kaduna follow-up assessments to address last mile challenges in onchocerciasis elimination

• To determine whether transmission is ongoing following four rounds of biannual ivermectin MDA
• To analyse the spatial relationship between parasitological, entomological and serological indicators of onchocerciasis transmission
• To explore the epidemiological, ecological and social factors associated with onchocerciasis recrudescence

Nigeria has made significant strides in eliminating onchocerciasis, a disease caused by the parasitic worm Onchocerca volvulus and transmitted by the black fly vector Simulium spp. In Kaduna, after more than 20 rounds of mass drug administration (MDA) with ivermectin, epidemiological and entomological assessments indicated that prevalence levels were below the thresholds to stop MDA. MDA was subsequently stopped in December 2017. However, recent studies (in advance of post-validation surveillance) provided evidence of ongoing transmission. As a result, the National Onchocerciasis Elimination Committee (NOEC) recommended biannual ivermectin treatment for two years, follow-up entomological assessments and in-depth epidemiological and social science investigations to explore the factors associated with onchocerciasis recrudescence.

Providing a guidance for addressing onchocerciasis recrudescence in endemic settings.