Study explores effect of land use and biodiversity changes on risk of zoonoses in Tana River County, Kenya

Orma Boran cattle crossing a river in Kenya (photo credit: ILRI/Rosemary Dolan).

The Dynamic Drivers of Disease in Africa Consortium is a research program that works to understand the relationships between ecosystems, zoonotic diseases, health and wellbeing in order to inform effective public health interventions.

Under this program, multidisciplinary country teams are studying four zoonotic diseases: henipavirus infection in Ghana, Lassa fever in Sierra Leone, Rift Valley fever in Kenya and trypanosomiasis in Zambia and Zimbabwe. The focus is on how changes in biodiversity, land use and climate affect disease transmission.

The development of irrigation schemes is thought to influence pathogen transmission in people and animals in several ways. For example, masses of stagnant water and high humidity support the development of disease vectors like mosquitoes. In addition, irrigated areas are likely to have a higher density of animal hosts like chicken and small ruminants.

In order to investigate the influence of irrigation and changes in biodiversity on the distribution of zoonoses, a cross-sectional study was carried out in Tana River County, Kenya, home to the Hola Irrigation Scheme. The zoonoses of interest were Rift Valley fever, Q fever, brucellosis, West Nile virus, dengue fever and leptospirosis.

Irrigation causes a decline in biodiversity as wildlife habitats are cleared to make way for crop agriculture. However, the linkages between biodiversity and disease risk remain unclear. It was also found that areas with a rich diversity of hosts have higher prevalence of multiple zoonotic pathogens as compared to areas with lower host diversity.

The study also found that while irrigated areas are infested with multiple species of mosquitoes (including primary vectors of Rift Valley fever), their high population densities alone are not enough to sustain the transmission of pathogens; reservoir hosts (for example, birds for West Nile virus) or other persistence mechanisms are required.

These and other findings from the study were presented at the 49th annual scientific conference of the Kenya Veterinary Association which was held in April 2015.

View the presentation, Land use, biodiversity changes and the risk of zoonotic diseases: Findings from a cross-sectional study in Tana River County, Kenya

 

New ILRI report reviews the use of a Rift Valley fever decision support tool in Kenya

Orma Boran cattle crossing a river in Kenya. Rift Valley fever can infect both cattle and people (photo credit: ILRI /Rosemary Dolan).

The International Livestock Research Institute (ILRI) has published a discussion paper on a study carried out to identify the successes and challenges associated with the use of a Rift Valley fever decision support tool in Kenya.

The decision support tool was developed by various stakeholders from government and non-government sectors following the 2006-07 outbreak of Rift Valley fever in East Africa. It identifies events leading to the disease outbreak and matches them with interventions that could be implemented at each point.

The study involved three activities:

• a review of literature to describe systems that could be used with the decision support tool and to identify how other frameworks have been used to support disease control policies
• focus group discussions and key informant interviews with farmer groups, local and international organizations and decision-makers in the Department of Veterinary Services
• a stakeholder workshop to validate the findings obtained and develop recommendations on ways to improve awareness and utilization of the framework

Download the discussion paper

Citation
Mbotha, D. and Bett, B. 2015. Utilization of the Rift Valley fever decision support tool in Kenya: Successes and challenges. ILRI Discussion Paper 28. Nairobi, Kenya: ILRI.