Molecular prevalence, genetic characterization and patterns ofToxoplasma gondiiinfection in domestic small mammals from Cotonou, Benin

Abstract

Toxoplasmosis, one of the most prevalent parasitic infections in humans and animals, is caused by the intracellular protozoan parasite Toxoplasma gondii. Small mammals play a key role as intermediate reservoir hosts in the maintenance of the T. gondii life cycle. In this study, we estimated the molecular prevalence and provide genetic diversity data for T. gondii in 632 small mammals sampled in four areas of Cotonou city, Benin. Both the brain and heart of each individual were screened through T. gondii-targeting qPCR, and positive samples were then genotyped using a set of 15 T. gondii-specific microsatellites. Prevalence data were statistically analyzed in order to assess the relative impact of individual host characteristics, spatial distribution, composition of small mammal community, and urban landscape features. An overall T. gondii molecular prevalence of 15.2% was found and seven genotypes, all belonging to the Africa 1 lineage, could be retrieved from the invasive black rat Rattus rattus and the native African giant shrew Crocidura olivieri. Statistical analyses did not suggest any significant influence of the environmental parameters used in this study. Rather, depending on the local context, T. gondii prevalence appeared to be associated either with black rat, shrew, or mouse abundance or with the trapping period. Overall, our results highlight the intricate relationships between biotic and abiotic factors involved in T. gondii epidemiology and suggest that R. rattus and C. olivieri are two competent reservoirs for the Africa 1 lineage, a widespread lineage in tropical Africa and the predominant lineage in Benin.

Toxoplasma gondiiandTrypanosoma lewisiinfection in urban small mammals from Cotonou, Benin, with special emphasis on co-infection patterns

“…gondii infections has been extensively discussed in our previous study [34]. For this reason, beyond the socio-environmental patterns that explain concomitant presence of both parasites in some rodent and shrew individuals which is the main focus of the present study, we first discuss briefly some aspects of T. lewisi infections as well.…”

“…Keeping in mind their usually quite high prevalence in small mammals (e.g., 15.2% for T. gondii [34] and 57.2% for T. lewisi [39]), the concomitant presence of both parasite in Cotonou city may provide valuable models to investigate further the role of co-infections in ecoevolutionary fate of zoonotic pathosystems in urban reservoir hosts communities.…”

“…In this study, we took advantage of an already existing small mammal-borne Toxoplasma dataset from Cotonou [34], to assess Trypanosoma lewisi presence/absence in the same rodent individuals, and then to investigate specifically the relationships between Toxoplasma and Trypanosoma infections in urban wild small mammals taking into account a panel of biological and environmental potentially confounding factors.…”

“…These data comprised 21 GIS-based landscape metrics that were specifically estimated at each district site (see details in [34,43]). Here, we focused on the 553 individuals that had already been investigated for the presence of T. gondii using molecular detection (see detailed protocols in [34] and T. gondii prevalence data in Table 1 as well as Supplementary Table ).…”

“…Although they display very different transmission modes, previous studies have shown that both parasites can circulate within common environments, especially in tropical areas where they can share the same reservoir hosts, specially rodents [6,32]. Thus, T. gondii has been identified in several commensal rodent species [33], including those investigated recently in Cotonou, Benin [34]. Rodents are also the main reservoirs of T. lewisi in Africa, especially the invasive genus Rattus , which was proposed to play a special role in its ecology and dissemination across the continent [35–38].…”