The Dynamic Drivers of Disease in Africa Consortium is focused on animal diseases which can be passed on to humans, known as zoonoses, in Africa. These are an important issue for poverty and public health because many emerging infectious diseases are zoonotic and they have a big impact poor people’s lives and livelihoods. As this is a complex issue our consortium involves many different types of researchers including social science, environmental science, veterinary experts, epidemiology, ecology and much more, really a ‘One Health’ consortium.
Recently, the Sierra Leone team conducted some research piloting and planning. There has been a journey to reach the point where different disciplines were able to meet and work together to pilot different methods. This trip allowed us some innovative opportunities to conduct multidisciplinary work and triangulate information found from different methods.
Lassa fever is the disease we are studying in Sierra Leone and symptoms include intermittent fever, headache, malaise and weakness. It is a serious disease and death can occur 10-14 days after onset of symptoms, so it is important to get to hospital quickly. We were lucky enough to be shown around the Lassa fever ward in Kenema Government Hospital, which is solely for people suffering from this disease and is the only hospital in the area equipped to deal with these cases and all other hospitals refer patients there. This helped to give us a clear understanding of the work they do and how cases are handled.
We visited two of the research villages and everywhere we went we received a warm welcome and the people living in the villagers willingly and enthusiastically gave us their time and knowledge on the issue of Lassa fever. In each village we started with a village meeting explaining why we were visiting and what we wanted to do.
In the first village we started with participatory landscape mapping, which involves the villagers drawing out their landscape, including crops, seasonal movements and reasons for different activities. We then moved on to the village epidemiological map which was a map of just the village area, showing which families live in different areas of the village, rodent movements, where possible risk areas for rodents were (for example, toilets, garbage areas, wells) and finally we asked where people had had fevers and the effects of these to see the patterns of disease.
We also conducted a rodent and fever matrix. This was to see the different types of rodents in the villages and the information the villagers had about them. No rats were identified with disease. We also asked them to identify the different types of fever people experienced. The villagers identified mild, medium and severe fevers and favoured native herbs for treatment. We are so interested in rodents because disease transmission is through a specific rodent species, so the prevalence of the virus is presumed to reflect the abundance of these.
In the second village we started with a focus group discussion based around questions we had from information that had been brought up in the previous village. The villagers in this area had benefitted from visits by the Lassa fever outreach team and knew more about fever and that rats carried disease.
This was a great and useful discussion which provided us with rich information. We then went on a transect walk. This is a walk through the village where we were accompanied by a small group of villagers through the landscape. We visited different land and ecosystem types (as marked on participatory maps), and used this as an opportunity for ‘on the spot’ conversations about where people see rodents, and the activities that are carried out in different places at particular times of year.
Information from both villages came together to make a picture, for example the village epidemiological map done in the first village showed schoolboys to be a risk group and the villagers in the second villagers talked of boys hunting cats and rats, giving one possible explanation for this and some further areas to discuss.
The Sierra Leone team has specialists in social science, environmental science and medicine, ecology and epidemiology. This is necessary because the disease is expected to increase due to climate and land use changes as well as improved monitoring of animal populations and pathogen screening.
All three teams will undertake research at the same time, gathering information on the same villagers, land and houses. The time points are based on key moments in the farming and land use calendar, annual climate/rainfall cycles, and likely important time points for rodent population dynamics, and therefore possible variations in Lassa transmission dynamics. Working together in this way will ensure that data is comparable and also allow teams to interact and learn from each other.
Examples of how the teams will work together include the environmental science and epidemiological team sharing information so decisions on where to place rat traps can be based on the land use information gathered. Additionally, the seasonal movements of men and women gained from the participatory mapping can be compared with the epidemiological data on prevalence of disease. This can be triangulated with fevers identified in the participatory work as well as looking at the village made epidemiological map and comparing it to the blood sample data. Another example is that the village epidemiological map (showing which people in which places have been sick and if this is where rats have been seen as well as showing their proximity to garbage, toilets, kitchens) can be triangulated with the process based modelling of who is most likely to get the disease. So, after a busy week of planning, piloting and sharing ideas between disciplines everyone is now excited to begin the next stage of the work!
by Catherine Holley, Research Officer, Dynamic Drivers of Disease in Africa and HEART Research Officer
Images: ‘Participatory mapping’ and ‘Transect walk’ . Credit: Catherine Holley.