First report of Providencia rettgeri, Colpodella spp., Ehrlichia spp., and Rickettsia hoogstraalii in ticks infesting goats of Pakistan

TL;DR

This study reports the first detection of several potential disease-causing microbes in ticks found on goats in Pakistan, highlighting risks to human and animal health.

Contribution

First report of Providencia rettgeri, Colpodella spp., Ehrlichia spp., and Rickettsia hoogstraalii in ticks from goats in Pakistan.

Findings

Four tick species were identified: Haemaphysalis punctata, Hyalomma anatolicum, Haemaphysalis sulcata, and Hyalomma excavatum.

Rickettsia hoogstraalii was detected in Haemaphysalis punctata ticks from Karak District.

Providencia rettgeri was found in Hyalomma excavatum ticks from Banuu District.

Abstract

Ticks are the second most important vector of infectious diseases, after mosquitoes, and can transmit several diseases of concern for both human and veterinary health. This study molecularly barcoded ticks collected from goats in Pakistan and screened for associated pathogens. From July 2023 to June 2024, examination of 253 goats (Capra hircus) in the 7th district of Khyber Pakhtunkhwa found 170 goats infested with 1,305 ticks, equating to a mean abundance of 5.15 ticks per goat. A phenol-chloroform technique was used to extract DNA and subsequently amplify the presence of pathogen DNA targeting 16S, 18S gltA, and ompA genes. Tick DNA was also amplified for the molecular confirmation of species using 12S rDNA partial sequence. All collected ticks were identified morphologically and molecularly as Haemaphysalis Punctata (519), Hyalomma anatolicum (380), Hae. sulcata (269), and Hy. excavatum (137), including 361 females, 323 males, 286 larvae and 198 nymphs. This study detected several tick-borne pathogens including Colpodella spp., Ehrlichia spp. and Rickettsia hoogstraalii, as well as detecting the bacteria Providencia rettgeri. Rickettsia hoogstraalii was found in Haemaphysalis punctata collected from Karak District. In contrast, Hy. excavatum from Banuu district were found to carry P. rettgeri. Hyalomma excavatum infesting goats in Buner, Chitral, and Hy. anatolicum form Kohistan, District tested positive only for Colpodella spp. whereas a single species of uncultured Ehrlichia spp. was found in Hae. sulcata collected from Mansehra, and Lakki Marawat district. This research’s novel report of human pathogenic microbes detected in ticks has implications for livestock and human health, as well as the role ticks potentially play in zoonotic disease transmission in Pakistan.

Ticks are well known for spreading diseases to humans and animals, yet the full range of pathogens they carry in many parts of the world—including Pakistan—remains poorly understood. In this study, we examined ticks collected from goats across seven districts of Khyber Pakhtunkhwa to better understand which species are present and what microbes they may transmit. Using both traditional identification and DNA sequencing, we found four common tick species and discovered several microorganisms of potential concern. These included Rickettsia hoogstraalii, Ehrlichia species, and Colpodella species—an emerging protozoan increasingly linked to human and animal infections. We also detected Providencia rettgeri, a bacterium typically associated with hospital acquired infections, marking the first time it has been reported in ticks. Although more research is needed to determine whether ticks can transmit these microbes to humans or livestock, our findings highlight the importance of continued surveillance in regions where people and animals live in close contact. This study provides new insight into the diversity of pathogens circulating in Pakistan’s tick populations and underscores the need for public health awareness and further investigation into their potential risks.

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