Crowding at Lake Chad : an integrated approach to demographic and health surveillance of mobile pastoralists and their animals

Despite substantial contribution to the economies of their countries, mobile pastoralists are marginalised in many aspects of their daily lives. Mobility complicates their access to schooling or health and veterinary services. They increasingly face challenges concerning their right to use natural resources in the south-eastern Lake Chad area. Mobile communities compete with sedentary ones over access to land and water, as more and more people move into the area of the receding lake.
Little is known about the demography of mobile pastoralists. They are poorly represented in national censuses because the assessment of mobile populations proves difficult and costly.
The longstanding partnership and a history of transdisciplinary experience, connecting the population, authorities and researchers in the study area has led to mutual trust and has contributed to an environment open to innovative approaches. The concept of One Health (combining human and animal healthcare and using synergies) is well known and appreciated in the area.
The general objectives of the work presented here were:
I.
To assess the density of sedentary and mobile people and their animals in the study zone at different time points.
II.
To test and evaluate a small-scale demographic surveillance system for mobile pastoralists and their animals using mobile phones.
III.
To investigate a disease perceived as a priority by mobile pastoralists.
Throughout the data collection we conducted semi-structured interviews with representatives of all sampled communities to assess the livelihood priorities of the sedentary as well as the mobile population. The main concerns were access to food, animal and human healthcare, access to resources and the frequent conflicts between mobile and sedentary communities, access to education, legal restrictions and the loss of harvest caused by natural disasters. The information from the interviews has served as a basis to more specifically define objective III and to analyse and discuss the results from the research addressing objectives I and II.
We assessed the density of people and animals using random coordinates to define sampling areas at four different time points from 2010 to 2012, at the beginning and at the end of the dry season. The approach allowed us to include the dynamics of population density between the seasons as well as between different years. Most of the human population lived in sedentary villages: 64.0 people per km2 (95%CI: 20.3 - 107.8) compared to mobile communities who were represented by 5.9 people per km2 (95%CI: 2.3 - 9.5) at the beginning and 17.5 people per km2 (95%CI: 10.7 - 24.3) at the end of the dry season. However, these proportions were inverted when comparing the livestock. From sedentary communities, there were 21.0 cattle (95%CI: 1.3 - 40.7) and 31.6 small ruminants (95%CI: 13.1 - 50.1) per km2. Mobile communities had on average during the dry season 66.1 cattle (95%CI: 41.1 - 91.2) and 102.5 (95%CI: 35.2 - 169.8) small ruminants per km2.
During the dry season we calculated a number of 86.6 Tropical Livestock Units (TLU) per km2, which exceeds up to five times the carrying capacities estimated for similar areas in the Sahel zone from older sources (14 – 23 TLU per km2). The high animal density and increasing farming activities, combined with fragile legal regulation of pastoralism and agriculture, causes frequent conflicts and leads to an unsatisfying situation for pastoralists as well as farmers. The participatory development and implementation of a new regulatory framework (“Code Pastoral”) is essential for both the local mobile and sedentary populations.
During the period of this research we equipped 20 mobile pastoralist camps with mobile phones and conducted regular phone interviews with the leaders of the camps and their wives. All ethnic groups of mobile pastoralists in the study area have been included. We collected data on one herd of livestock per camp and all the households belonging to this herd. After the interviews, credit was transferred to the participant’s phone, and the amount was doubled if we could speak to the wife, which was an incentive for women to participate in the study. The data was validated with personal visits and for the herds with the calculation of a demographic model. Travel routes were also recorded and mapped. The results clearly showed the feasibility of demographic surveillance of mobile communities using mobile phones. All participants complied with the study during the entire period and made great efforts to be available for the interviews. As a consequence, we recommend scaling up to a large scale mobile health and demographic surveillance system (mHDSS).
The communities surveyed perceived fasciolosis as a major problem for their animals. Since infection with this liver fluke reduces body weight and milk production, it also has economic consequences for the families and can threaten food security. We assessed the dimension of the infection intensity during one year with the examination of all slaughtered animals in the three slaughter slabs of the veterinary zone of Grédaya. For each animal a short questionnaire was filled in. The overall prevalence was 22.7 (95%CI: 19.9 – 25.4%) including all animal species. For cattle, the prevalence was highest with 68% (95%CI 60-76%), for goats 12% (95%CI 10-16%) and for sheep 23% (95%CI 16-30%). Animals which had grazed at the shores of Lake Chad (with contact to open water) had a much greater risk of infection. The ethnic group of the owner was strongly associated with the risk of infection. Groups who traditionally herd their animals in close proximity of the lake such as Peul or Kouri had a prevalence between 95% and 100% for cattle, compared to Gorane and Kanembou people, who tend to stay in dryer areas, with 0% prevalence. The geospatial distribution showed that animals close to the lake were more likely to be infected. We have therefore concluded that Lake Chad is the sole source of infection and recommend treating animals feeding close to the lake regularly, as recommended by local veterinarians. However, access to treatment and treatment quality remain an issue of concern.