One Health Approach to Arbovirus Control in Africa: Interests, Challenges, and Difficulties

Abstract

The "One Health" concept considers that human and animal health, and ecosystems are closely related and aims to make a link between ecology and human and veterinary medicine. Due to the explosion in population growth along with the geographic and climatic conditions (equatorial and/or tropical climate), Africa is becoming a major hotspot for various socio-health issues associated with infectious diseases, including arboviruses. The incontestable advantages of a One Health approach in Africa lie in the fight against pathogens, such as arboviruses, and in the preservation of environmental, animal, and human health to ensure that the increasing high needs of this population are met as well as their protection against potential epidemics. The One Health strategy gives us a glimpse of the difficulties and challenges that the African continent faces. The importance of this approach in Africa is to establish guidelines and strategies for effective solutions and changes in behavior and harmful activities. Overall, the establishment of high-quality global health policies in the framework of the global health standards program would provide healthy and sustainable human-animal-environmental interactions for the welfare of all.

Keywords: Africa; One Health; animal health; arbovirus; environmental health; human health; infectious diseases.

Figure 1

Schematic representation of the interrelatedness of animal, environmental, and human factors justifying a One Health approach: impact of environmental and animal health on human health, and, conversely, the impact of human behaviors and activities on the emergence and re-emergence of micro-organisms. (Adapted from WOAH: World Organization for Animal Health; FAO: Food and Agriculture Organization).

Figure 2

Distribution of major viral zoonotic diseases in Africa over the last 10 years: Blue represents countries with reported outbreaks of viral zoonotic diseases in the last 10 years. The virus name and years of diagnosis are indicated. (CCHFV: Crimean–Congo hemorrhagic fever virus; DENV: dengue virus; RVFV: Rift Valley fever virus; HEV: hepatitis E virus; YFV: yellow fever virus.

Figure 3

Transmission cycle of RVFV with different modes of transmission: (1) Humans, livestock, domestic and wild animals are infected through mosquito bites (red line). (2) Direct transmission between humans and domestic animals (exposure to body fluids, blood, and tissues of infected animals), between domestic animals and between humans (blood transfusion) (blue dotted line). (3) Vertical transmission in vectors and domestic animals (purple line). (4) Likely vertical transmission in wild animals and humans (green line).

Figure 4

Transmission cycle of CCHFV: (1) Wild animal tick–host interactions, affecting, or not, animal health (blue line) and (2) animal farming (blue line), (2) and (3). The overlap of human health with animal health through the routes of virus transmission, most commonly through tick bites or tick crushing, and secondarily through contact with infected animal blood during slaughter or during contact with animals in livestock and agricultural areas (blue line). (3) Human-to-human transmission can also occur in a domestic or nosocomial infection when no appropriate personal protective equipment is used (blue line). (4) Transstadial and transovarian transmission between ticks is possible (red circle).

Figure 5

DENV transmission cycles: (1) Wild forest animals are infected by the bites of mosquito-Aedes (blue line), this cycle is the sylvatic cycle. (2) The dwellings near the forests or within the sylvatic cycle are named the zones of emergence and/or re-emergence of the virus. The movement of populations infected by mosquito bites to urban areas leads to the urban cycle. (3) The urban cycle with transmission to urban mosquitoes, then transmission to humans induced by infected urban mosquitoes (blue line). (4) Transovarian transmission of infected mosquitoes is possible both in the forest and in urban areas (red circle).