Molecular Survey and Spatial Distribution of Rickettsia spp. in Ticks Infesting Free-Ranging Wild Animals in Pakistan (2017-2021).

Abid Ali,Itabajara Da Silva Vaz,Farman Ullah,Hafsa Zahid,Tetsuya Tanaka,Ismail Zeb,Shehla Shehla,Haroon Ahmed

doi:10.3390/pathogens11020162

Abstract

Rickettsia spp. associated with ticks infesting wild animals have been mostly neglected in several countries, including Pakistan. To address this knowledge gap, ticks were collected during 2017 to 2021 from wild animals including cats (Felis chaus), Indian hedgehogs (Paraechinus micropus), and wild boars (Sus scrofa). The collected ticks were morpho-molecularly identified and screened for the detection of Rickettsia spp. Morphologically identified ticks were categorized into four species of the genus Rhipicephalus: Rhipicephalus haemaphysaloides, Rh. turanicus, Rh. sanguineus sensu lato (s.l), and Rh. microplus. Among 53 wild animals examined, 31 were infested by 531 ticks, an overall prevalence of 58.4%. Adult female ticks were predominant (242 out of 513 ticks collected, corresponding to 46%) in comparison with males (172, 32%), nymphs (80, 15%) and larvae (37, 7%). The most prevalent tick species was Rh. turanicus (266, 50%), followed by Rh. microplus (123, 23%), Rh. sanguineus (106, 20%), and Rh. haemaphysaloides (36, 7%). Among the screened wild animals, wild boars were the most highly infested, with 268 ticks being collected from these animals (50.4%), followed by cats (145, 27.3%) and hedgehogs (118, 22.3%). Tick species Rh. haemaphysaloides, Rh. turanicus, and Rh. sanguineus were found on wild boars, Rh. haemaphysaloides, and Rh. microplus on cats, and Rh. turanicus on hedgehogs. In a phylogenetic analysis, mitochondrial cytochrome C oxidase 1 (cox1) sequences obtained from a subsample (120) of the collected ticks clustered with sequences from Bangladesh, China, India, Iran, Myanmar, and Pakistan, while 16S ribosomal DNA (16S rDNA) sequences clustered with sequences reported from Afghanistan, Egypt, India, Pakistan, Romania, Serbia, and Taiwan. Among Rickettsia infected ticks (10/120, 8.3%), Rh. turanicus (7/10, 70%), and Rh. haemaphysaloides (3/10, 30%) were found infesting wild boars in the districts Mardan and Charsadda. The obtained rickettsial gltA gene sequences showed 99% and ompA gene sequences showed 100% identity with Rickettsia massiliae, and the phylogenetic tree shows ompA clustered with the same species reported from France, Greece, Spain, and USA. This study emphasizes the need for effective surveillance and control programs in the region to prevent health risks due to tick-borne pathogens, and that healthy infested wild animals may play a role in the spread of these parasites.

Highlights

Interactions between domestic and wild animals have increased due to urbanization, deforestation, and anthropogenic activities which enhance the risk of emergence of zoonotic diseases [1]
Cats have been found infested with different tick species including Ixodes ricinus, I. hexagonus, I. trianguliceps in Great Britain [3], I. scapularis, I. pacificus, I. banksi, Amblyomma americanum, A. maculatum, Dermacentor occidentalis, Otobius megnini, I. affinis I. angustus, I. cookie, D. variabilis, Haemaphysalis longicornis in USA [4,5,6], Rhipicephalus sanguineus in Pakistan
Wild boars have been observed parasitized by different tick species such as D. atrosignatus, D. steini, D. compactus, D. marginatus, D. reticulatus, Rh. turanicus, Rh. sanguineus, I. ricinus, and H. hystricis in the Asian and Southeast Asian countries [18,19,20,21,22]

Summary

Introduction

Interactions between domestic and wild animals have increased due to urbanization, deforestation, and anthropogenic activities which enhance the risk of emergence of zoonotic diseases [1]. Free roaming behavior of wild cats in search of food increases the chances of interaction with diverse habitats and animals, and enhances the chances of exposure to different ticks and tick-associated pathogens. The movement of wild boars towards suburban and urban areas has been observed, resulting in their interaction with domestic animals, spreading ticks and tick-associated pathogens [17]. Wild boars have been observed parasitized by different tick species such as D. atrosignatus, D. steini, D. compactus, D. marginatus, D. reticulatus, Rh. turanicus, Rh. sanguineus, I. ricinus, and H. hystricis in the Asian and Southeast Asian countries [18,19,20,21,22]. Reports have shown the occurrence of tick-borne pathogens such as A. marginale, A. phagocytophilum, and B. burgdorferi sensu lato (s.l.) associated with ticks infesting wild boar in Europe, Portugal, and Iran [14,23]

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Results

Conclusion