Increasing local disease preparedness and surveillance capacity for global health security: a cluster-randomised control trial


Background: Low-income countries are often characterized by poor health infrastructures and lack systems needed to timely detect and control disease outbreaks, such as the 2014-16 Ebola Viral Disease and COVID-19. In such contexts, a “One Health” approach, which involves investing in both human and animal health systems, plausibly improves local health outcomes by enabling early detection of zoonotic diseases before they are transmitted to humans, and by timely triggering a health system response needed to mitigate possible outbreaks. There is an urgent call to translate One Health into action and create inclusive and sustainable policies. There is however limited direct evidence on the gains from One Health approaches. We contribute here by using a randomised intervention to assess the impact of a participatory community-based One Health program.

Methods: As part of a cluster-randomised control trial, government and communities recruited, trained and installed Community Animal Health Workers (CAHWs) to work alongside Community Health Workers (CHWs) in 300 randomly selected rural villages in Sierra Leone. Another 63 villages were randomly selected as control sites and had CHWs exclusively. CAHWs provided essential animal health services, disseminated information regarding animal and human health best practices, and actively participated in surveillance efforts by reporting suspected disease symptoms to government supervisors. We investigated program impacts on human health as well as key intermediary outcomes, including animal health, animal and human health-related behaviours, integration into public services, and household wealth. The trial is registered at (# 21660) and OSF.

Findings: In July and August 2017, the community-based One Health program successfully recruited, trained and installed CAHWs across 287 villages. Throughout the program’s duration, spanning from July 2017 to July 2019, the CAHWs reported on 17,813 suspected disease-related events. Using survey data from 2,538 respondents, collected in March and April 2020, we found no evidence of impacts on human health (-0.010 standard deviation units (SDU), 95% CI -0.131, 0.111). The program did improve intermediary outcomes including animal health (0.157 SDU, 95% CI 0.022, 0.293), animal husbandry practices (0.127 SDU, 95% CI -0.022, 0.276), human health behaviours (0.137 SDU, 95% CI -0.007, 0.281), integration into public services (0.300 SDU, 95% CI 0.116, 0.484), and households’ attitudes towards disease reporting (0.263 SDU, 95% CI 0.109, 0.418).

Interpretation: Participatory community-based One Health interventions can increase preparedness against zoonotic diseases.

Kevin Grieco
Kevin Grieco
PhD Candidate

Political scientist interested in state capacity and development.