Conference Agenda

Session

CP3: Tropical Health 15 min talk sponsored by QIMR Berghofer, Centre for Tropical Health & Emerging Diseases

Time:

Tuesday, 30/June/2026:

11:20am - 11:35am

Session Chair: Darren Gray, QIMR Berghofer
Session Chair: Chika Zumuk, Queensland Institute of Medical Research

Location: Lecture Theatre 3

Boulevard Room 1

Presentations

Spatio-temporal modelling of onchocerciasis prevalence in Ghana: Identifying transmission hotspots for targeted elimination

Millicent Opoku^1,2,3,4, David Dean³, Himal Shrestha⁵, Kwadwo K. Frempong⁴, Dziedzom K. de Souza⁴, Sellase Pi-Bansa⁴, Joseph H. N. Osei⁶, Joseph Opare⁷, Odame Asiedu⁷, Ernest Mensah⁷, Warwick N. Grant², Daniel A. Boakye^4,8, Shannon Hedtke^1,2

¹La Trobe Institute of Molecular Sciences, La Trobe University, Melbourne, Australia; ²Department of Microbiology, Anatomy, Physiology and Pharmacology, La Trobe University, Melbourne, Australia; ³Department of Ecological, Plant and Animal Sciences, La Trobe University, Melbourne, Australia; ⁴Department of Parasitology, Noguchi Memorial Institute for Medical Research (NMIMR), College of Health Sciences, University of Ghana, Accra, Ghana; ⁵The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Australia; ⁶Biomedical and Public Health Research Unit, Water and Research Institute, Council for Scientific and Industrial Research (CSIR), Accra, Ghana; ⁷Neglected Tropical Diseases Programme, Ghana Health Service, Accra, Ghana; ⁸The END FUND, New York, USA

Onchocerciasis (river blindness), caused by Onchocerca volvulus and transmitted by Simulium blackflies, remains a public health challenge in sub-Saharan Africa. Although prevalence has declined following aerial larviciding under the Onchocerciasis Control Programme (OCP) and African Programme for Onchocerciasis Control (APOC) through community-directed treatment, achieving the World Health Organization elimination target of sustained microfilarial (mf) prevalence below 1% requires identifying areas of persistent transmission. Mf prevalence data from 1,353 surveys across 671 villages were obtained from the Expanded Special Project for Elimination of Neglected Tropical Diseases and the Ghana Neglected Tropical Diseases Programme. Environmental predictors were structured around four transmission constructs: climatic suitability, flowing-water probability, vector blood-feeding probability, and bioregional land-use context. A Bayesian spatiotemporal zero-inflated beta-binomial model was fitted using Stan via brms in R, incorporating ecozone-specific temporal smooths, a two-dimensional spatial smooth, and nested random effects. MF prevalence was spatially and temporally heterogeneous. Northern ecozones declined to near-elimination levels by 2015, whereas southern forest and forest-agriculture transition zones showed slower and less consistent declines. The Tano-Ankobra transmission zone emerged as a persistent hotspot. This first comprehensive spatiotemporal analysis of onchocerciasis across Ghana highlights the need for intensified, targeted interventions in southern Ghana to achieve elimination.