Nematodes diversity in Mastomys rodents (Rodentia: Muridae) and molecular characterization of Trichuris species in the Mnisi Community, South Africa

Abstract

Nematodes comprise of many species with diverse life histories and zoonotic potential. Understanding the distribution and diversity of nematodes in the commensal rodent genus Mastomys is crucial for assessing their impact on wildlife and livestock, and potential of zoonotic disease transmission. The current study investigated the nematode diversity in Mastomys species rodents in three habitats and characterized the recovered Trichuris sp. using morphometric and molecular techniques at a wildlife-human/domestic animal interface in the Savanna biome in Mnisi communal area, Mpumalanga, South Africa. Nematodes were recovered and identified in the gastrointestinal tracts of 68 M. natalensis and 27 M. coucha rodents which were trapped in crop, village and natural habitats in the Mnisi communal area in October 2020. Nematodes were microscopically identified using morphometric measurements. Molecular characterization of Trichuris sp. was achieved through deoxyribonucleic acid (DNA) extraction, polymerase chain reaction (PCR), Sanger sequencing and phylogenetic analyses of three genes: internal transcribed spacers (ITS) 1, ITS 2 and cytochrome B (CytB). Data were analyzed using descriptive statistics, univariate models, a zero-inflated negative binomial generalized linear model, and a binomial generalised linear model, to establish the frequency, measures of central tendency and the relationships between nematode counts or occurrence and predictor variables using R statistical software. Nematodes were recovered in 20% of the examined rodents, with a total of 46 nematodes recovered, representing two species: Trichuris sp. (mean abundance of 0.31± 0.22) primarily from the caecum and Abbreviata sp. (mean abundance of 0.15±0.14) primarily from the stomach. Almost all the rodents were infected with only one nematode species, while one rodent exhibited mixed infection of both nematode species. No significant differences (p>0.05) in nematode prevalence were observed between male and female Mastomys spp. Univariate and multivariable analysis confirmed a lack of significant differences (p>0.05) in nematode abundance concerning habitat type, rodent species, and sex. The obtained novel Trichuris sp. ITS1, ITS2 and CytB sequences, clustered in a distinct clade from published sequences, but showing genetic relationships with known Trichuris spp. The current study emphasizes the importance of integrating morphometric identification and molecular analysis to accurately categorize Trichuris spp. and suggests a need for a larger sample size per habitat type in future research on nematode diversity.