Ticks and accompanying pathogens of domestic and wild animals of Kerala, South India

Molecular characterisation of Amblyomma integrum circulating in southern India

Amblyomma integrum is a large gooseberry sized longirostrate tick (when fully repleted) found in India and Sri Lanka. In Kerala (India), this tick is commonly found in the forest and its fringe areas frequently infesting deer and hence it is locally known as "maan chellu / maanunny" (deer tick). In the present study, molecular characterisation and phylogenetic analysis of A. integrum collected from the area grazed by the sambar deer (Rusa unicolor) of Kerala, south India was performed using three molecular markers viz., the mitochondrial cytochrome c oxidase subunit 1 (COI), mitochondrial 16S ribosomal RNA, and nuclear 18S ribosomal RNA genes. Cytochrome c oxidase subunit 1 (COI) gene showed better resolving ability for elucidating the evolutionary relationship of A. integrum and identified two distinct clades, viz., A and B. The Tamil Nadu isolates of south India and Marayoor isolate 1 (from Idukki district of Kerala bordering with Tamil Nadu) belonged to clade A. Majority of Wayanad isolates from Kerala, occupied clade B. The intraspecific genetic distance among the A. integrum species ranged from 0.00 to 13.34%. Between clades A and B, the genetic distance observed was 11.49%. The clade B isolates were genetically close to A. geoemydae (GD: 1.22%). Morphological variations between the clades included darker exoskeletal coloration in clade A and distinct differences in the shape of basis capitulum. Further analysis using Assemble Species by Automatic Partitioning (ASAP) and Generalized Mixed Yule Coalescent (GMYC) provided additional insights. Assemble Species by Automatic Partitioning (ASAP) identified 26 Molecular Operational Taxonomic Units (MOTUs) at a threshold distance of 5.38%, supporting the species partition of A. integrum clade B. Generalized Mixed Yule Coalescent (GMYC) analysis retained the same species complex (A. integrum-geoemydae Complex) inferred from the ASAP analyses. It could be inferred from the present study that the A. integrum clades A and B could be two different putative pseudocryptic species.

First report of Anaplasma spp., Ehrlichia spp., and Rickettsia spp. in Amblyomma gervaisi ticks infesting monitor lizards (Varanus begalensis) of Pakistan

Ticks pose significant health risks to both wildlife and humans due to their role as vectors for various pathogens. In this study, we investigated tick infestation patterns, tick-associated pathogens, and genetic relationships within the tick species Amblyomma gervaisi, focusing on its prevalence in monitor lizards (Varanus bengalensis) across different districts in Pakistan. We examined 85 monitor lizards and identified an overall mean intensity of 19.59 ticks per infested lizard and an overall mean abundance of 11.98 ticks per examined lizard. All collected ticks (n = 1019) were morphologically identified as A. gervaisi, including 387 males, 258 females, 353 nymphs, and 21 larvae. The highest tick prevalence was observed in the Buner district, followed by Torghar and Shangla, with the lowest prevalence in Chitral. Lizard captures primarily occurred from May to October, correlating with the period of higher tick infestations. Molecular analysis was conducted on tick DNA, revealing genetic similarities among A. gervaisi ticks based on 16S rDNA and ITS2 sequences. Notably, we found the absence of A. gervaisi ITS2 sequences in the NCBI GenBank, highlighting a gap in existing genetic data. Moreover, our study identified the presence of pathogenic microorganisms, including Ehrlichia sp., Candidatus Ehrlichia dumleri, Anaplasma sp., Francisella sp., Rickettsia sp., and Coxiella sp., in these ticks. BLAST analysis revealed significant similarities between these pathogenic sequences and known strains, emphasizing the potential role of these ticks as vectors for zoonotic diseases. Phylogenetic analyses based on nuclear ITS2 and mitochondrial 16S rDNA genes illustrated the genetic relationships of A. gervaisi ticks from Pakistan with other Amblyomma species, providing insights into their evolutionary history. These findings contribute to our understanding of tick infestation patterns, and tick-borne pathogens in monitor lizards, which has implications for wildlife health, zoonotic disease transmission, and future conservation efforts. Further research in this area is crucial for a comprehensive assessment of the risks associated with tick-borne diseases in both wildlife and humans.

Prevalence of ixodid ticks on goats and risk factors for tick-borne diseases in humans in the Kyasanur forest disease endemic area of Kerala, India

In India, tick-borne diseases are prevalent in many states due to the presence of tick vectors. However, information on disease-causing ticks from domestic animals and the associated risk factors for residents living in the disease-endemic area is lacking. Therefore, we conducted this study to identify ixodid ticks in goats and human risk factors in three villages of the Wayanad district of Kerala. We examined 202 goats and collected 741 ticks, of which 69.8% were ticks belonging to the genus Haemaphysalis. The maximum number of ticks was collected from Thirunelli (81.3%), followed by Noolpuzha (76.27%) and Pulpally (45.6%). Overall, H. bispinosa Neumann, 1897 (54.6%), was the most common species, followed by H. turturis Nuttall and Warburton, 1915 (38.0%), H. spinigera Neumann, 1897 (5.4%), and H. intermedia Warburton and Nuttall, 1909 (1.8%). We included 428 participants (men and women) in this study. The average age of the respondents was 43 years. We found significant associations between accessing the forest for cattle grazing and other activities and tick-borne diseases (χ2 = 9.5, p = 0.002), between workers who were bitten by ticks and tick-borne diseases (χ2 = 3.8, p = 0.05), and between number of tick bites per day > 6 and tick-borne diseases (χ2 = 12.1, p = 0.001). The high frequency of Haemaphysalis spp. found in goats highlighted the risk of tick exposure and tick-borne diseases, such as Kyasanur forest disease in humans, and the need for the development and implementation of effective measures to control ticks.

Molecular Survey of Rickettsia raoultii in Ticks Infesting Livestock from Pakistan with Notes on Pathogen Distribution in Palearctic and Oriental Regions

Ticks are hematophagous ectoparasites that transmit different pathogens such as Rickettsia spp. to domestic and wild animals as well as humans. Genetic characterizations of Rickettsia spp. from different regions of Pakistan are mostly based on one or two genetic markers and are confined to small sampling areas and limited host ranges. Therefore, this study aimed to molecularly screen and genetically characterize Rickettsia spp. in various tick species infesting camels, sheep, and goats. All the collected tick specimens were morphologically identified, and randomly selected tick species (148) were screened molecularly for the detection of Rickettsia spp. by amplifying three rickettsial DNA fragments, namely, the citrate-synthase gene (gltA), outer-membrane protein A (ompA), and outer-membrane protein B (ompB). After examining 261 hosts, 161 (61.7%) hosts were found infested by 564 ticks, including 287 (50.9%) nymphs, 171 (30.3%) females, and 106 (18.8%) males in five districts (Kohat, Dera Ismail Khan, Lower Dir, Bajaur, and Mansehra). The highest occurrence was noted for Hyalomma dromedarii (number = 72, 12.8%), followed by Haemaphysalis sulcata (n = 70, 12.4%), Rhipicephalus turanicus (n = 64, 11.3%), Rhipicephalus microplus (n = 55, 9.7%), Haemaphysalis cornupunctata (n = 49, 8.7%), Hyalomma turanicum (n = 48, 8.5%), Hyalomma isaaci (n = 45, 8.0%), Haemaphysalis montgomeryi (n = 44, 7.8%), Hyalomma anatolicum (n = 42, 7.5%), Haemaphysalis bispinosa (n = 38, 6.7%), and Rhipicephalus haemaphysaloides (n = 37, 6.6%). A subset of 148 ticks were tested, in which eight (5.4%) ticks, including four Hy. turanicum, two Ha. cornupunctata, one Ha. montgomeryi, and one Ha. bispinosa, were found positive for Rickettsia sp. The gltA, ompA, and ompB sequences revealed 100% identity and were phylogenetically clustered with Rickettsia raoultii reported in China, Russia, USA, Turkey, Denmark, Austria, Italy, and France. Additionally, various reports on R. raoultii from Palearctic and Oriental regions were summarized in this study. To the best of our knowledge, this is the first report regarding genetic characterization and phylogenetic analysis of R. raoultii from Pakistan. Further studies to investigate the association between Rickettsia spp. and ticks should be encouraged to apprise effective management of zoonotic consequences.

A Review of Rickettsial Diseases Other Than Scrub Typhus in India

Rickettsial diseases (RD) are widely reported all over the world. Scrub typhus (ST) is a major tropical infection which is well documented all over India. Therefore, the index of suspicion of scrub typhus is high among physicians with regard to patients presenting with acute febrile illness (AFI) and acute undifferentiated febrile illness (AUFI) in India. Rickettsial diseases other than ST (non-ST RDs), which include spotted fever group (SFG) rickettsioses and typhus group (TG) rickettsioses are not uncommon in India, but the index of suspicion is not as high as ST unless there is a history of the presence of fever with rashes and/or recent arthropod bites. This review aims to look into the Indian scenario on the epidemiology of non-ST RDs, especially the SFG and TG rickettsioses based on various investigations, spectrum of clinical presentation, challenges and gaps in knowledge to suspect and diagnose these infections.

Transovarial transmission of pathogenic protozoa and rickettsial organisms in ticks

Transovarial transmission (TOT) is an efficient vertical transmission of pathogens that is observed in many arthropod vectors. This method seems to be an evolutionarily unique development observed only in Babesia sensu stricto (clade VI) and Rickettsia spp., whereas transstadial transmission is the common/default way of transmission. Transovarial transmission does not necessarily contribute to the amplification of tick-borne pathogens but does contribute to the maintenance of disease in the environment. This review aims to provide an updated summary of previous reports on TOT of tick-borne pathogens.

New records of Amblyomma gervaisi from Pakistan, with detection of a reptile-associated Borrelia sp

Ticks are hematophagous ectoparasites of terrestrial and semi-aquatic vertebrates that may transmit microorganisms to their hosts. Spirochetes of the genus Borrelia are common in ticks and an incipient group has been identified in association with reptiles and their tick parasites. To overcome the knowledge deficit, this study aimed to morphologically and molecularly identify ticks infesting wild lizards and to molecularly assess Borrelia spp. associated with these ticks in Pakistan. For this purpose, free-ranging monitor lizards (Varanus bengalensis) from Khyber Pakhtunkhwa province, Pakistan, were examined for tick infestations. A total of 776 ticks were collected from 36/63 lizards, resulting in a prevalence of 57% (95% CI 44.7-69.3%), overall mean intensity of 21.5 (95% CI 18.9-24.1) ticks per infested lizard, and overall mean abundance of 12.3 (95% CI 9.25-15.4) ticks per examined lizard. All ticks were morphologically identified as Amblyomma gervaisi. The morphological identification of the ticks was molecularly confirmed through sequencing fragments of the mitochondrial 16S rRNA gene. In addition, a fragment of nuclear second internal transcribed spacer (ITS2) was generated for the first time for A. gervaisi. Phylogenetic analysis inferred from tick 16S rRNA gene partial sequences predicted a close evolutionary relationship of the collected A. gervaisi ticks with conspecific sequences from India, which shared 94.5% identity. Through two PCR assays targeting fragments of the borrelial genes, 16S rRNA and flaB, 19 (18%) out of 108 ticks yielded borrelial DNA. Phylogenetic analyses inferred from DNA sequences of the two borrelial genes revealed that the Borrelia sp. from A. gervaisi detected in this study belonged to the reptile-associated Borrelia group (REP). This is the first molecular report of ticks infesting monitor lizards and associated Borrelia sp. in Pakistan. The preliminary phylogenetic analyses of A. gervaisi may assist in understanding the molecular epidemiology of Amblyomma spp.

Molecular detection of pathogens in the ova and unfed larvae of Rhipicephalus annulatus and Haemaphysalis bispinosa ticks infesting domestic cattle of south India

This study aimed to investigate the presence of pathogens in the engorged ticks infesting domestic cattle, their ova, and unfed larvae. The engorged female ticks infesting domestic cattle of Wayanad district of Kerala, south India were collected and kept for oviposition. The dead females after the complete oviposition, their egg masses, and unfed larvae were screened for the presence of various pathogens by specific PCRs. The presence of Babesia bigemina, Anaplasma marginale, A. phagocytophilum, and Rickettsia spp. similar to R. raoultii was confirmed in Rhipicephalus annulatus ticks, their egg masses, and unfed larvae. Theileria orientalis was detected in Rh. annulatus females, but not in their egg masses or progenies. The presence of A. phagocytophilum and Rickettsia spp. similar to R. raoultii was confirmed in Haemaphysalis bispinosa ticks, their egg masses, and unfed larvae too. The presence of coinfections of B. bigemina with A. phagocytophilum and A. marginale were detected in Rh. annulatus ticks and their progenies.

Effects of flumethrin on the germinative cells of engorged females of Rhipicephalus annulatus

Chemical acaricides are widely used for the effective control of ticks in India. The synthetic pyrethroids, are one of the most popular chemical acaricides with selective neurotoxic potential. Flumethrin is a type II synthetic pyrethroid used extensively in veterinary practice in India. The present study was undertaken to evaluate the cytotoxic effects of flumethrin on the engorged females of Rhipicephalus annulatus using entomological parameters, histology, electron microscopy and relative quantification of receptors of dopamine and GABA_B mRNAs. Adult immersion test (AIT) using flumethrin (100 ppm), revealed twenty per cent mortality of ticks, hundred per cent inhibition of fecundity and complete blocking of hatching of the laid eggs. Microscopic analysis of the structure of the ovaries after 24 h of treatment with flumethrin (90 ppm) revealed changes, viz., reduction in size with the presence of amorphous material inside stage I oocytes, wrinkled boundary and chromatin fragmentation of nucleus of stage II oocytes, vacuoles around the germinal vesicle, thickening of the nuclear membrane and chromatin clumping of stage III oocytes and reduction in size and shape of mature stage IV and V oocytes. Also, a large number of vacuoles were observed throughout the pedicel cell region of stage II and III oocytes. Ultrastructurally, irregular nuclear membrane, swelling as well as crystolysis of mitochondria and detachment of external and internal layers of the basal lamina of oocytes were the major structural alterations confirming direct damaging effects of flumethrin on the germinative cells. The relative quantification of the expression of dopamine D₁, dopamine D₂ and GABA_B receptors by quantitative real-time PCR (qRT PCR), revealed the upregulation of dopamine D₁ receptor and downregulation of receptors of dopamine D₂ and GABA_B in the ovary of treated ticks.

Molecular investigation and clinical management of Hepatozoon Canis infection in an Indian jackal - a case report

BACKGROUND

Hepatozoonosis is a common tick-borne illness reported from all over the world. The infection has been well documented in dogs and cats, and has also been identified in wild canids and felids. India is home to many canid species; however, the incidence of Hepatozoonosis in wild canids is rarely reported. A wide variety of protocols have been discussed for the clinical management of the infection in companion animals; however, the suitability of treatment protocols in wild canids is understudied. The current case report highlights the clinical management of Hepatozoonosis in an Indian jackal and molecular investigation to provide vital insights into the epidemiology of the disease.

CASE PRESENTATION

A paraplegic Indian jackal was rescued from Melghat Tiger Reserve, Maharashtra, India. The animal had extensive decubital ulcers on the left pin bone and could not walk; however, the animal was active and dragged the hindlimb during locomotion. The vital parameters, blood and serum investigations were normal. Post physiotherapy, massage and infrared therapy, the animal could walk but started knuckling, resulting in injuries. Eight weeks into rehabilitation, the animal had a steep fall in haemoglobin concentration, platelet count, weight loss and was diagnosed with Hepatozoonosis. Considering the altered vital parameters, the jackal was rationally treated with Doxycyclin @ 20 mg/Kg O.D. (Once Daily) for 45 days along with supportive therapy. The jackal recovered after the treatment and led a normal life.

CONCLUSION

Mono-drug regime using Doxycycline was effective in the alleviation of H.canis infection in jackal. The drug was effective in alleviating the clinical presentation without alteration of vital parameters. The molecular investigation provided qualitative inputs in understanding the epidemiology of Hepatozoon in wild canids.

South Indian zebu dwarf cattle show higher natural resistance to tick infestation compared to crossbreds: preliminary observations

The present study aimed to evaluate the influence of various factors on the host resistance of cattle against tick infestation in Kerala State, South India. The number of naturally infested semi-engorged female ticks present on the cattle was counted on a sample cattle population across the four regions of Kerala. Then, the animals were grouped based on the tick count. The chi-square test and Fisher exact test were used to identify the effects of genetic and non-genetic factors on tick burden in cattle. It was found that the Holstein Friesian crossbred and Jersey crossbred cattle had a significantly higher level of tick infestation than the indigenous Vechur breed (Bos indicus). No tick infestation was observed in indigenous Kasaragod Dwarf cattle (B. indicus). Tick infestation was more in heifers and dry animals than lactating animals. However, the sex of the animal and the stage of lactation did not influence the tick load. Tick infestation was also influenced by parity, grazing, and region.

Modulation of the PGE2-Mediated Pathway in the Eclosion Blocking Effect of Flumethrin and Terpenoid Subfraction Isolated from Artemesia nilagirica in Rhipicephalus annulatus

Prostaglandins are a group of important cell-signaling molecules involved in the regulation of ovarian maturation, oocyte development, egg laying and associated behaviors in invertebrates. However, the presence of prostaglandin E₂ (PGE₂), the key enzymes for PGE₂ biosynthesis and its interference by drugs were not investigated previously in the ovary of ticks. The present study was undertaken to assess the modulation of the PGE₂-mediated pathway in the eclosion blocking effect of flumethrin and terpenoid subfraction isolated from Artemisia nilagirica in Rhipicephalus annulatus ticks. The acaricidal activities and chemical profiling of the terpenoid subfraction were performed. The localization of the cyclooxygenase1 (COX1) and prostaglandin E synthase (PGES) enzymes and the quantification of PGE₂ in the ovaries of the ticks treated with methanol (control), flumethrin and terpenoid subfraction were also undertaken. In addition, the vitellogenin concentration in hemolymph was also assayed. Both flumethrin and the terpenoid subfraction of A. nilagirica elicited a concentration-dependent inhibition of fecundity and blocking of hatching of the eggs. The COX1 could not be detected in the ovaries of treated and control ticks, while there was no significant difference observed in the concentration of vitellogenin (Vg) in them. The presence of PGES in the oocytes of control ticks was confirmed while the immunoreactivities against PGES were absent in the vitellogenic oocytes of ticks treated with flumethrin and terpenoid subfraction. The levels of PGE₂ were below the detection limit in the ovaries of the flumethrin-treated ticks, while it was significantly lower in the ovaries of the terpenoid subfraction-treated ticks. Hence, the prostaglandin E synthase and PGE₂ were identified as very important mediators for the signaling pathway for ovarian maturation and oviposition in ticks. In addition, the key enzyme for prostaglandin biosynthesis, PGES and the receptors for PGE₂ can be exploited as potential drug targets for tick control. The detection of PGES by immunohistochemistry and quantification of PGE₂ by LC-MSMS can be employed as valuable tools for screening newer compounds for their eclosion blocking acaricidal effects.

Morphological and molecular data of Hepatozoon ursi in two brown bears (Ursus arctos) in Turkey

Species of Hepatozoon Miller, 1908 are vector-borne parasites that infect domestic and wild animals worldwide. Hepatozoon ursi Kubo, Uni, Agatsuma, Nagataki, Panciera et al., 2008 was reported from bears (Ursidae) in Japan and India. The present study represents the first report of infection with H. ursi in Turkish brown bears (Ursus arctos Linnaeus) by microscopic and molecular analysis. Two dead brown bears were found in Uzundere and Pasinler districts of Erzurum. Blood and visceral organ (spleen and liver) samples were delivered to laboratory by the Nature Conservation and National Parks officers. Detected gamonts were evaluated based on morphological features and confirmed as gamonts of H. ursi. The size of gamonts and parasitemia were 8.2 × 3.5 μm (6.9-8.7 × 3.0-3.9 μm; n = 12) and 0.6% (6/1000 leukocytes), respectively. The blood and visceral organ samples were positive for species of Hepatozoon by PCR targeting partial sequence of 18S rDNA. Sequence analysis of newly obtained sequences of H. ursi showed 98.8-100% identity with previously sequenced isolates of H. ursi. Sequences of H. ursi from Erzurum were identical to each other and showed 100% identity with isolates of H. ursi from ticks Ixodes ricinus (Linnaeus), Rhipicephalus turanicus Pomerantzev and Hyalomma marginatum Koch collected from two brown bears in Turkey (GenBank accession numbers MN463021, MN463022, MN905023). Analysis of partial sequences of the 18S rRNA gene of H. ursi showed that Turkish isolates differ in NT substitutions found at three different positions [72 (A→G), 537 (A→G) and 570 (A→T)]. This study provides morphological and molecular data of H. ursi infection in brown bears from two districts of Erzurum, Turkey. Further studies are needed to elucidate whether brown bears have any eco-epidemiologic importance in the life cycle of H. ursi in wildlife.

Molecular Detection and Identification of Babesia spp., Theileria spp., and Anaplasma spp. in Sheep From Border Regions, Northwestern China

Babesia, Theileria, and Anaplasma are important causative agents of tick-borne diseases that severely affect sheep. However, there is paucity in the occurrence genetic diversity of the infections of tick-borne diseases in sheep in border regions, northwestern China. In this study, nested polymerase chain reaction (nPCR) assays and gene sequencing were used to identify tick-borne Babesia spp., Theileria spp., and Anaplasma spp. infections in border regions, northwestern China. Out of 323 samples tested in this study, 225 (69.7%) sheep were infected with Babesia spp., Theileria spp., and Anaplasma spp. Two hundred six (63.8%), 60 (18.6%), 54 (16.7%), 51 (15.8%), 32 (9.9%), 19 (5.9%), and 16 (5.0%) were positive for A. ovis, B. motasi-like, A. bovis, T. uilenbergi, A. phagocytophilum, T. luwenshuni, and B. motasi-like Xinjiang, respectively. The most common dual infection was with A. ovis and B. motasi-like while the most frequent triple coinfection was A. ovis, B. motasi-like, and T. uilenbergi with coinfection rates of 17.0% (55/323) and 5.0% (16/323), respectively. Sequencing analysis indicated that A. ovis MSP4, A. phagocytophilum epank1, A. bovis 16S rRNA, B. motasi-like rap1-b, B. motasi-like Xinjiang rap1-a, T. luwenshuni 18S rRNA, and T. uilenbergi 18S rRNA from border regions, northwestern China, showed 99–100% identity with documented isolates from other countries. To the best of the authors' knowledge, this is the first report of T. uilenbergi and T. luwenshuni infections of sheep in border regions, northwestern China. Furthermore, these findings provide important data for understanding the distribution of Babesia, Theileria, and Anaplasma in sheep between border countries and China.