Risk mapping of Japanese encephalitis using swine movement network analysis and environmental factors including land use patterns in Nepal

Japanese encephalitis (JE) is a serious cause of mortality and disability in humans, particularly children in Nepal. JE has been endemic in the southern Terai area for a very long time and in more recent years has spread to the hilly areas including the Kathmandu Valley.

 

A major vaccination program of people has reduced the incidence of this disease but cases still commonly occur. Pigs play a significant role as amplifiers of JE virus increasing the risk of mosquitoes transmitting infection from pigs to people living in the vicinity of pig farms. There are still many gaps in information on the possible role of the movement of pigs over short distances on increasing JE risk for people within endemic areas, and the possible role of long-distance movement of viraemic pigs in establishing new endemic areas of infection.

 

A collaborative investigation project involving two studies is being conducted to address these gaps by Nepalese doctors and veterinarians undertaking in a 2-year One Health Epidemiology Fellowship as part of the ‘Integrating Education and Action for One Health’ program funded by the European Union and implemented by Massey University.

 

The first study is using social network analysis to characterise the movement patterns of pigs both within and out of JE endemic areas in a pig rearing district in the Terai region of Nepal. Results will be used to help generate hypotheses regarding the association between JE risk and the movement patterns of pigs.

 

A second study will use satellite derived environmental data to generate a map of JE risk across Nepal, which will contribute to modelling the risk of JE for people by combining environmental risk data, pig population data and pig movement patterns in a spatially referenced simulation model. The model will be used to evaluate a range of national policies for controlling JE in Nepal.

 

The Fellowship participants are from the human health, animal health, and wildlife sectors and are studying together in a Master’s degree program in One Health epidemiology and biosecurity. Through studies such as these they are applying their knowledge and collaborating to reduce the risks of endemic and emerging epidemic diseases transmitted from animals and wildlife to people in their country.

 

The ‘Integrating Education and Action for One Health’ program uses a One Health approach to strengthen capability and promote collaborative relationships between the human, animal and wildlife health sectors in Afghanistan, Bangladesh, Bhutan and Nepal. This is key to managing endemic and emerging epidemic and pandemic disease threats.

 

The ‘Integrating Education and Action for One Health’ program is funded by the European Union and implemented by Massey University. The contents of this article are the sole responsibility of Massey University.