CRC TRR 228 Project B02
Linking social-ecological transformations and arbovirus prevalence
B02 Future Infections
Improve understanding of the impact of large-scale land-use changes like conservation, agricultural intensification, and road development on facilitating the introduction and spread of vector-borne pathogens into a new environment.
Conservation, agricultural intensification, and infrastructural development are land-use changes happening across rural parts of eastern and southern Africa. Against the backdrop of climate change, these competing and sometimes overlapping changes happen at the expense of traditional pastoralism and small-scale agriculture. Creating a balance among these processes of future-making involves identifying lines of distinction and zones of interaction between the different entities (boundaries). Thus, improving our understanding of the resulting ecological and social or behavioral changes remains key to uncovering this seemingly complex situation. Conservation of wildlife in national parks and game reserves is designed to boost the tourism sector of African countries, thereby contributing to massive capital flow. These practices are currently being complemented by the creation of community-managed conservancies, which have drastically increased in numbers in the last two decades. Community conservancies often happen on traditional rangelands affecting pastoralism. Additionally, wildlife corridors and dispersal areas are being put under conservation in order to provide connectivity between larger protected areas. Such corridors and dispersal areas provide space for migrating large ungulates but at the same time increase human–wildlife interactions. A sharp increase in wildlife and game on privately owned farms in southern Africa also raises contact rates among wildlife, livestock, and humans. While joint land use of conserved areas may have long-term economic benefits for both pastoralism and conservation, we are dealing with a high level of uncertainty here as this setup may unintentionally facilitate spillover infections from wildlife reservoirs to livestock or humans, thus presenting an additional health challenge to humans and their livestock. The presence of a great variety of infectious pathogens detected in the first funding phase may be responsible for high levels of uncertainties in shaping the future. This calls for more detailed analyses of risks and perceptions of arboviral diseases by different communities in KAZA and KRV, key among them pastoralists, using a holistic One Health approach. We will investigate in greater detail how land-use changes will affect the prevalence and impact of vector-borne diseases in the KAZA and KRV regions of Africa.
Research Regions: KAZA TFCA, Kenyan Rift Valley
Conservation, agricultural intensification, and infrastructural development are land-use changes happening across rural parts of eastern and southern Africa. Against the backdrop of climate change, these changes are at the expense of pastoralism and small-scale agriculture. In the Kenyan Rift valley (KRV), these practices are complemented by the creation of community-managed conservancies, while in southern Africa transboundary conservation areas such as the Kavango Zambezi Transfrontier Conservation Area (KAZA) park have been established. These land use changes are meant to improve livelihoods through tourism, employment creation and transportation. However, conservation is associated with increased human-livestock-wildlife interactions and the emergence of arboviral diseases. Other land use changes such as agricultural intensification and major infrastructural development can facilitate the spread of invasive plants which may further influence distribution patterns of arboviruses and their vectors. We therefore intend to use a One health approach to evaluate the effect of these landscape changes on arboviral disease.
- How do pastoralists and agro-pastoralists perceive the growing risk of zoonotic arboviral diseases and is this linked to socio-ecological transformations?
- How do major land use and biodiversity changes influence arboviral disease emergence and risk?
- Do invasive plants influence life history traits of disease vectors and subsequently their competence?
- Semi-structured interviews
- Soil and rangeland quality analysis
- Analysis of wildlife diversity and density
- Analysis of arbovirus infection rates in mosquitoes, small mammals and cattle across different land-use types
- Morphological and competence assessment of mosquitos in relation to invasive plant litter
Key Findings from Phase I
We found that elephant densities in KAZA affected mosquito species composition as well as mosquito densities. Similarly, in the KRV land-use changes caused by invasive plants like Parthenium, Prosopis and Lantana had a strong effect on mosquito community composition. Several pathogenic arboviruses, like West Nile virus that can cause encephalitis in humans were found in Cx. univittatus mosquitoes in KAZA. In total, we detected ten strains of WNV which grouped in two different phylogenetic clades. Our data indicate that two different variants were simultaneously circulating in Namibia and suggest that WNV may contribute to unknown disease aetiologies. In addition, novel orthobunya- and orbiviruses that are likely to cause malformations and abortions in livestock, were detected in mosquitoes and midges in KAZA. The presence of such a great variety of infectious pathogens may be responsible for high levels of uncertainties in shaping the future.
Relation to the CRC
B02 embraces the CRC concept of bridging boundaries by improving our understanding of how shifting bio-cultural boundaries may facilitate the introduction of vector-borne pathogens into a new environment. The focus is on large-scale land use changes such as conservation, agricultural intensification, and road development that present significant socio-ecological changes. Together with climate change these changes may have unintended side-effects on human and animal health. Emphasis will be on vector abundance/diversity and prevalence of vector-borne zoonotic diseases, and how the creation of conservancies, the accidental introduction and spread of invasive plants (resulting from agricultural intensification), and the construction of roads favour disease emergence. The focus will be on high-risk communities in the KAZA and KRV regions especially pastoral communities and how the resulting ecological and behavioural changes impact rural livelihoods. This work will be in collaboration with CRC projects A01, A02, A04, A05, B01, and C07.
Agha, S.B., Alvarez, M., Becker, M., Fèvre, EM., Junglen, S., Borgemeister, C. 2021. Invasive alien plants in Africa and the emergence of arboviral diseases – A review and research outlook. Viruses 13 (1), 32. DOI
Guggemos, H., Fendt, M., Hermanns, K., Hieke, C., Heyde, V., Mfune, JKE, Borgemeister, C., Junglen, S. 2021. ‘Orbiviruses in biting midges and mosquitoes from the Zambezi region, Namibia’, Journal of General Virology, vol. 102, no. 9. DOI
Guggemos, H., Fendt, M., Hieke, C., Heyde, V., Mfune, JKE, Borgemeister, C., Junglen, S. 2021 Simultaneous circulation of two West Nile virus lineage 2 clusters and Bagaza virus in the Zambezi region, Namibia. PLoS Neglected Tropical Diseases 15(4): e0009311. DOI
van Dam, A., van Engelen, W., Müller-Mahn, D., Agha, S., Junglen, S., Borgemeister, C., & Bollig, M. (2023). Complexities of multispecies coexistence: Animal diseases and diverging modes of ordering at the wildlife–livestock interface in Southern Africa. Environment and Planning E: Nature and Space, 0(0). Full Text
Collaboration between CRC Projects B02, C03, A04 and the ERC Rewilding leads to new interdisciplinary publication on “Complexities of multispecies coexistence”
Prof. Dr. Christian Borgemeister
University of Bonn
Prof. Eric Fèvre
International Livestock Research Institute Nairobi
Prof. Dr. Sarah Junglen
Dr. Joel Lutomiah
Kenya Medical Research Institute
Dr. John Mfune
University of Namibia
Dr. Erdwin Muradzikwa
University of Namibia
University of Bonn
Dr. Tatenda Chuiya
University of Bonn