Detection Of Leptospira And Seasonal Prevalence Of Fleas Collected From Small Mammals In Mukwe Constituency, Kavango East Region Of Namibia

Abstract

Biotic and abiotic factors can alter the abundance and community composition of mammals and in turn that of associated parasites. The aim of the study was to measure the impact of climatic variables (temperature and relative humidity) on mammal populations and on the population dynamics of associated micro- and ecto-parasites. For this, the current study described prevalence and diversity of pathogenic Leptospira, the etiological agent of leptospirosis, and fleas, arthropod vectors of medical importance in mammals sampled over a period of 11 months in the Kavango East region of Namibia. In total, 121 small mammal hosts were examined for Leptospira using a molecular method (Multilocus sequence typing method) and yielded an overall prevalence rate of 9.9%. However, only a single Leptospira species could be identified as Leptospira kirschneri, on one host species (Saccostomus campestris). Throughout the study period, almost all mammal species harboured the same flea species, which included Cryptonella numae (1.8%), Pulex irritans (43.0%), Pariodontis riggenbachi riggenbachi (12.9%), Synosternus caffer (3.9%) and Xenopsylla species (38.3%). Using the Kruskal-Wallis test, the monthly population fluctuation of fleas varied significantly on M. natalensis (χ 2=29.440, df=10, P=0.001), S. pratensis (χ 2 =30.521, df=10, P=0.001) and S. campestris (χ 2=32.681, df=10, P=0.0001). However, no significant difference in the number of fleas per month was found for G. leucogaster (χ 2=10.831, df=10, P=0.371). The Pearson correlation test revealed that fleas abundance on small mammal hosts was weakly positively correlated with temperature (r=0.3, df=9, N=11, P=0.310) and strongly positively correlated with relative humidity (r=0.6, df=9, N=11, P=0.109), this same comparison for fleas showed a weak positive correlation (r=0.4, df=9, N=11, P=0.224). Lastly, there was a very strong positive correlation (r=0.8, df=9, N=11, P=0.0058) between average abundance of small mammals and average abundance of fleas. Therefore, climatic variables (temperature and relative humidity) were found to have an influence on the abundance of small mammals and fleas.