Prevalence of tick infestation and molecular characterization of spotted fever Rickettsia massiliae in Rhipicephalus species parasitizing domestic small ruminants in north-central Nigeria.

Nusirat Elelu,Mashood Abiola Raji,Adefolake Ayinke Bankole,Ndudim Isaac Ogo,Shola David Ola-Fadunsin,Sally Jane Cutler,Brian Stevenson

doi:10.1371/journal.pone.0263843

Nusirat Elelu, Mashood Abiola Raji + Show 5 more

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https://doi.org/10.1371/journal.pone.0263843

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Abstract

Ticks are of great menace to animal and human health. They serve as vectors to both animals and human pathogens including Rickettsia species. Tick-borne rickettsiosis in West Africa remains incompletely understood. We determined the prevalence of tick infestation among small ruminants and molecularly described a clinically significant spotted fever Rickettsia massiliae from Rhipicephalus ticks collected from North-Central, Nigeria. A total of 352 small ruminants comprising of 152 sheep and 200 goats that were brought for slaughter at the major small ruminant slaughterhouse in Ilorin were examined for the presence of ticks. The collected Rhipicephalus species were subjected to molecular studies to detect and characterize Rickettsia massiliae. Of the small ruminants examined, 21 sheep and 46 goats were infested with ticks representing 13.82% and 23.00% respectively. Eight and nine different species of ticks were detected in sheep and goats respectively, with Rhipicephalus (Boophilus) decoloratus being the most prevalent tick species in both sheep and goats. There was a significant difference (p <0.01) in the prevalence of the different tick species collected in sheep and in goats. Based on the PCR amplification of the 23S-5S intergenic spacer (IGS), only 2 of the 142 Rhipicephalus tick samples screened for R. massiliae were positive (1.41%; 95% CI = 0.39-4.99). Rickettsia massiliae was detected from Rhipicephalus turanicus collected from sheep. Sequences obtained from the PCR carried out by amplifying Rickettsia 23S-5S IGS showed 99-100% close identity with members of the R. massiliae group. This study has for the first time confirmed the presence of spotted fever group Rickettsia massiliae from feeding ticks in Nigerian small ruminants. Further investigations to determine the possible pathogenic role of human R. massiliae infection in Nigeria would be beneficial.

Highlights

Small ruminants rearing is one of the most important aspects of agriculture in most parts of the world [1]
We report our findings in small ruminants from North-Central Nigeria using sensitive molecular methods to identify the tick-borne Rickettsia species present in small ruminants
Eighty-one ticks were collected from sheep, while 159 ticks were collected from goats

Summary

Introduction

Small ruminants (sheep and goat) rearing is one of the most important aspects of agriculture in most parts of the world [1]. This has contributed greatly to the growth and development of many economies worldwide [1, 2]. Ticks are the second most important arthropod parasite after mosquitoes, that affect mammals and birds [8, 9]. They are ranked as the most economically important ectoparasites of livestock in the tropics, including sub-Saharan Africa [10, 11]. A number of tick species can act as vectors of pathogens causing a number of tick-borne diseases, which causes a serious impairment to the health, welfare, production, and reproduction of ruminants including sheep and goats [9, 12]

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