Ixodid tick population on small domestic ruminants (goat and sheep) in different agro-climatic regions 

Highlights

• •First extensive survey of tick in domestic small ruminants in the State of Tamil Nadu, India covering 220 villages.
• •The most prevalent tick species is Haemaphysalis intermedia, a vector of the Ganjam virus.
• •First time reported of Rhipicephalus ramachandrai on domestic small ruminant in Tamil Nadu.

Abstract

Tick borne diseases are emerging in various agro-climatic regions, affecting both humans and domestic animals such as small ruminants (goats and sheep). The distribution and abundance of tick vectors across agro-climatic regions are influenced by seasonal variations. A comprehensive tick survey was carried out on small ruminants in 220 villages across seven agro-climatic regions during the four seasons of Tamil Nadu. A total of 51,694 ticks were collected, with 36,522 (70.6 %) from goats and 15,712 (30.4 %) from sheep, representing 16 species from four genera. Haemaphysalis intermedia was the most prevalent tick species (89.7 %), while Rhipicephalus microplus was the most abundant (7.8) ticks in small domestic ruminants. Tick species diversity was higher in goats (14 species) compared to sheep (13 species). The highest species diversity in goats was recorded in the hilly agro-climatic regions (10 species) and during the summer season (11 species), while the highest species diversity in sheep was observed in the southern agro-climatic region (10 species) and during the winter season (12 species). H.intermedia was the most prevalent species in both goats (89.4 %) and sheep (97.0 %). The highest abundance was reported Rh.microplus in goats (8.14) and H.intermedia in sheep (7.4). Infestation intensity for H.intermedia was observed highest in both goats (5.6) and sheep (6.0), with an infestation rate of 42.5 % in both species. This study provides the first comprehensive report on tick species diversity in small ruminants in Tamil Nadu, revealing the highest species diversity and documenting several species not previously reported in this region.

Graphical abstract

Introduction

In India, livestock such as cattle, buffaloes, goat and sheep play a crucial economic role for many people, especially in rural and urban areas, by providing essential resources such as milk and meat (Nasirian, 2024). Ectoparasites, including fleas, lice and ticks have a significant impact on livestock populations by transmitting various pathogens, including protozoa, helminths, bacteria, and viruses, leading to substantial mortality and economic losses (Muhammad et al., 2021; Nasirian, 2023). Livestock not only sustain these ectoparasites in the environment but also contribute to the zoonotic transmission of tick borne diseases to human (Defaye et al., 2022). Among livestock, small ruminants, such as sheep and goats, are particularly valuable in rural areas of India. However, these animals also serve as important hosts for tick vectors, allowing ticks to complete their life cycle around human habitation, thereby facilitating the transmission of zoonotic diseases. Tick infestations further contribute to economic losses by reducing fertility and causing mortality in livestock.

In India, the first comprehensive check list of tick species diversity across various hosts was published in 1938 (Sen, 1938), with the most recent update in 1997 (Geevarghese et al., 1997). In small ruminants, 25 species of Ixodid ticks have been reported, including species from the genera Amblyomma spp (1 species), Rhipicephalus spp (3 species), Haemaphysalis spp (13 species), Hyalomma spp (4 species), Ixodes spp (3 species) and one species from Dermacentor (Geevarghese et al., 1997). In Tamil Nadu, seven tick species were reported from small ruminants in various agro-climatic regions and seasons, based on veterinary clinic records two decade ago (Latha et al., 2004). In our previous study, 10 tick species were identified in small ruminants across different agro-climatic regions of Tamil Nadu (Elango et al., 2024).

The development and availability of molecular diagnostic techniques have enhanced the detection of pathogens in both ticks and the hosts, increasing the importance of studying tick-borne diseases. Several bacterial pathogens, including Rickettsia sp (Belkahia et al., 2021), Coxiella burnetti (Amin et al., 2022), Anaplasma sp (Selim et al., 2022), Borrelia sp and Ehrlichia sp (Uilenberg, 1997), have been isolated from blood samples or ticks collected from small ruminants. These bacteria are known to cause diseases such as spotted fever, Q fever, anaplasmosis, Lyme disease and ehrlichiosis. Among these Coxiella burnetti infection can lead to abortions in the sheep and goat (Liu et al., 2024). In terms of viral infections, Ganjam virus has been isolated from febrile illness sheep (Ghalsasi et al., 1981) as well as from H.intermedia (Boshell et al., 1970), the most prevalent and abundant tick species in small ruminants. Antibodies against Crimean Congo hemorrhagic fever (CCHF) have also been detected in small ruminants.

Although previous studies (Latha et al., 2004) have documented tick species diversity, no comprehensive information is available on the prevalence, abundance, and infestation intensity across different agro-climatic regions and seasons in Tamil Nadu. Our previous study (Elango et al., 2024) reported tick prevalence in different agro-climatic regions, and the present study expands this work to cover all seasons in Tamil Nadu.

Section snippets

Study villages

Tamil Nadu, located at the southernmost tip of the Indian peninsula, is divided into 37 districts, which are further classified into seven agro- climatic regions. A study on tick species diversity across different agro-climatic regions of Tamil Nadu was initially conducted from June 2021 to June 2022 (Elango et al., 2024). The present study expands on this work, extending the survey to additional districts and covering all four seasons from July 2022 to June 2024. 

Results

A tick survey was conducted on 8684 small ruminants, comprising 2362 sheep and 6322 goats, across 220 villages in different agro-climatic regions of Tamil Nadu. The overall tick infestation rate was 45.59 %, with a slightly higher infestation in sheep (46.87 %) compared to goats (45.11 %). The highest tick infestation rates were recorded during the Northeast Monsoon, with 48.96 % in sheep and 47.60 % in goats.

In total, 51,694 ticks were collected, with 36,522 (70.6 %) from goats.

Discussion

India holds the top global rank for goat populations and is second in sheep populations (Anonyms, 2025). Tamil Nadu ranks seventh in India for goat populations. Smaller ruminants such as goats and sheep are primarily reared for meat production, making them economically important for rural communities. However, these animals also serve as reservoirs for tick populations, which can transmit a variety of pathogens. Tick borne viruses such as Tick-borne encephalitis.

Conclusion

The present study reports high tick’s species diversity in small ruminants, including several tick- borne vectors. The most important tick species identified were H.intermedia, Rh.microplus and H.bispinosa and Rh.haemaphysaloides, all of which were found across different agro-climatic regions and seasons. Small ruminants play a significant role in maintaining tick vector populations in the local environment. The occurrence of rare species such as H.aculeata, Haemaphysalis davisi. 

Ethics approval

Approved from Institution Animal Ethical committee.

Summary

The population dynamics of ixodid ticks (hard ticks) on small domestic ruminants such as goats and sheep vary significantly across different agro-climatic regions due to differences in temperature, humidity, vegetation, and host availability. In tropical and subtropical regions, tick infestations tend to be higher due to favorable warm and humid conditions that support tick survival and reproduction. Semi-arid and arid zones, while having lower overall humidity, still host specific tick species adapted to drier conditions. Common ixodid ticks infesting small ruminants include Rhipicephalus, Hyalomma, Amblyomma, and Haemaphysalis species, with regional dominance depending on the climate and ecosystem. Tick burden is often higher during the wet and warm seasons, correlating with increased vegetation and host activity. These infestations negatively impact animal health by causing anemia, skin damage, reduced weight gain, and by transmitting pathogens such as Theileria, Babesia, and Anaplasma. Effective tick management requires region-specific control strategies, including the use of acaricides, rotational grazing, and integrated pest management tailored to local ecological conditions.