First Molecular-Based Confirmation of Dermacentor marginatus and Associated Rickettsia raoultii and Anaplasma marginale in the Hindu Kush Mountain Range

Abstract

Ticks of the genus Dermacentor Koch, 1844 (Acari: Ixodidae) are poorly known systematically due to their habitation in harsh topographic environments and high mountains. Dermacentor ticks are diversely distributed in the Palearctic, Nearctic, and Oriental regions. There is no available information on the occurrence of Dermacentor marginatus in Pakistan; thus, the current investigation aimed the first morphological and molecular confirmation of this species and associated Anaplasma marginale and Rickettsia raoultii. Ticks were collected from goats (Capra hircus) and morphologically identified. Genomic DNA was extracted from 18/26 (69.23%) tick specimens, including 11 males and 7 females (1 unfed and 6 fed females). Extracted DNA was subjected to PCR for the amplification of genetic markers like 16S rDNA and cox1 for ticks, 16S rDNA for Anaplasma spp., and gltA and ompB for Rickettsia spp. A total of 26 D. marginatus ticks composed of 19 males (73.07%) and 7 females (26.9%) [1 (3.84%) unfed and 6 (23.07%) fed females] were collected from goats. According to amplicons via BLAST analysis, the 16S rDNA sequence showed 97.28–98.85% identity and the cox1 sequence showed 95.82–98.03% identity with D. marginatus. Additionally, the 16S rDNA sequence for Anaplasma sp. was detected in D. marginatus that showed 100% identity with Anaplasma marginale. Rickettsial gltA and ompB sequences for Rickettsia sp. showed 100% identity with Rickettsia raoultii. In phylogenetic analysis, ticks’ 16S rDNA and cox1 sequences clustered with the same species. In phylogenetic analysis, A. marginale based on 16 rDNA clustered with A. marginale, while gltA and ompB sequences clustered with R. raoultii. This is the first study on the genetic characterization of D. marginatus and associated A. marginale and R. raoultii in Pakistan. The northern areas of Pakistan, which need to be explored in terms of ticks and associated pathogens due to their zoonotic threats, have been neglected due to the inaccessible climatic conditions.

First record of Alectorobius coniceps (Ixodoidea: Argasidae) and Dermacentor sp. (Ixodoidea: Ixodidae) in Pakistan

“…However, they are among the most neglected tick genera in the Oriental region, including Pakistan. Importantly, research in Pakistan has considerably focused on the exploration of ticks and tick-borne pathogens in the last half-decade ( 4 , 5 , 9 , 39 , 53 – 65 ). This study provides the first morphological and molecular record of A. coniceps and Dermacentor sp.…”

“…Although demonstrating characteristics of both the Palearctic and Oriental regions, the knowledge regarding the genera Alectorobius and Dermacentor is limited within Pakistan. No tick species from the Alectorobius genus has been reported, while only Dermacentor raskemensis and Dermacentor marginatus have been identified morphologically or molecularly within the Dermacentor genus in this country ( 39 – 43 ). To address this knowledge gap, in this study, we reported the occurrence and genetic characterization of Dermacentor and Alectorobius species in Pakistan using morphological and molecular approaches.…”