Leptospirosis and Extensive Urbanization in West Africa: A Neglected and Underestimated Threat?

Abstract

Leptospirosis affects 1 million and kills 60,000 people annually, but it remains poorly documented in Africa. We aim to describe the large West African Conurbation Corridor where the omnipresence of slums, water and close animal/human interactions may result in high leptospiral risk. Though scarce, data from this region point towards the wide circulation of pathogenic leptospires in the urban environment as well as in humans. However, because of the absence of reliable surveillance systems together with lack of awareness, the absence of reference laboratory and/or a high number of infected people showing only mild manifestations, it is likely that the burden is much higher. We believe raising awareness of leptospirosis may have a positive impact on many vulnerable African city dwellers, as the disease is a preventable and treatable.

Fine‐scale prevalence and genetic diversity of urban small mammal‐borne pathogenic Leptospira in Africa: A spatiotemporal survey within Cotonou, Benin

“…The present study confirms the moderate prevalence of pathogenic Leptospira among urban small mammals of South Benin. However, taking into account the strong abundance and density of these reservoir hosts within cities, especially slums, as well as the recurrent flooding episodes that characterized this region, it is expected that inhabitants are at high risk of exposure for leptospirosis (Dobigny et al, 2018). Our longitudinal monitoring documented one of the highest levels of genetic diversity of small mammal‐borne leptospire species and genogroups that has ever been observed at such a fine‐scale, with the co‐occurrence of several genetic Leptospira species and strains within the same neighbourhoods and even households.…”

“…the so‐called Abidjan‐Lagos corridor; Choplin, 2019), where hundreds of thousands of urban dwellers live in socio‐environmentally degraded conditions. In this region, leptospiral burden, though under‐documented, is expected to be important (Dobigny et al, 2018). Contrary to what is usually observed in European and American towns where only rats and mice coexist, the small mammal communities from the coastal West African city centres still harbour native species due to the ongoing but incomplete bio‐invasion of cosmopolitan rodents (e.g.…”

Leptospirosis and Coinfection: Should We Be Concerned?

“…These situations increase reservoir populations and compromise basic health care services, sanitation, waste management, whilst exposing humans to Leptospira. The particular areas that overflow by heavy rainfalls that cannot be drained due to the faulty sanitation network, causing rodents to abandon their burrows and contaminate the water with their urine [66,67]. In addition to contaminated floodwater, rodents increase the possibility of transmitting bacteria to humans through cuts and abrasions of the skin [68], following prolonged immersion in contaminated water [51].…”

Genetic diversity and origins of invasive black rats (Rattus rattus) in Benin, West Africa

“…To date, no genetic diversity and phylogeographic data on black rats are available for Benin while the species is thought to be present in all localities (De Visser et al 2001, Hima et al 2020 and abundant in most households in the south of the country (Houémènou et al 2019, Hima et al 2020, posing a risk of pathogen transmission to humans (Houémènou 2013, Dobigny et al 2018. Therefore, the objective of this study was to fill this gap in our knowledge and to document the history of Benin's colonization by the black rat through the study of its mitochondrial genetic diversity.…”