Hyalomma anatolicum resistance against ivermectin and fipronil is associated with indiscriminate use of acaricides in southwestern Balochistan, Pakistan

Unveiling Misconceptions among Small-Scale Farmers Regarding Ticks and Tick-Borne Diseases in Balochistan, Pakistan

Ticks and tick-borne diseases (TBDs) pose potential health threats to small-scale farmers of grazing animals in the upper highlands of Balochistan, Pakistan. This study was conducted based on a questionnaire survey involving 153 farmers of grazing animals in seven districts to access their knowledge, attitudes, and practices regarding ticks and TBDs. Odds ratios and 95% confidence intervals, based on Fisher's test, were used to assess risk factors for determining preventive measures. The findings revealed a low level of knowledge among the participants. For instance, there was a lack of awareness of the effects of climate change and the economic impact of ticks on animal health. The essential precautions, such as the non-indiscriminate use of acaricides, wearing dark-colored clothing, and limiting children's interaction with grazing animals, were often overlooked. However, the farmers had a positive attitude towards tick control, but they mostly relied on the knowledge of local communities. The neglect of such measures places these farmers and their children at risk of contracting TBDs. This study also indicates minimal involvement from the government in educating farmers and controlling ticks. The role of stakeholders, including the government, non-governmental organizations, veterinary doctors, and local farmer communities, is crucial to address these issues and to implement effective training programs that address misconceptions about ticks and TBDs. Overall, this study highlights the importance of implementing awareness and education programs to address the misconceptions about ticks and TBDs among farmers.

Impact of Farm Management Practices on Tick Infestation in Punjab's Livestock: A Comprehensive Epidemiological Study

Tick infestation poses an important challenge to livestock in Pakistan. Farm management practices and environmental variables can influence tick infestation prevalence in animals. To this end, a cross-sectional survey of 96 farms in four different geographical districts (24 farms from each district) was conducted in Punjab, Pakistan, between October 2021 and January 2022. An epidemiological questionnaire was designed focusing on farm management practices and their impact on tick infestations at these farms. Data were collected via in-person interviews. Regional and farm-specific variables' associations were evaluated using Pearson's chi-square test and Fischer's exact test, respectively. A multivariable logistic regression model was used to identify significant risk factors. This study identified that using soft bedding materials, e.g., wheat straw, leaf litter or plain soil posed a significant risk of tick infestation. Additionally, the absence of quarantine measures, open sheds and inadequate drainage were found as contributing factors in univariable analysis. Higher tick prevalence in the hotter seasons highlighted the influence of Punjab's extreme weather on tick infestation. Despite regular veterinary visits and the use of acaricidal drugs, the prevalence of tick infestation at these farms suggested potential drug resistance in the ticks. The study recommended establishing quarantine practices, improving farms' drainage systems and bedding and using a combination of chemical and traditional remedies to tackle drug resistance in ticks. Education and awareness programs on tick-borne diseases and control measures are advocated to reduce the tick infestation burden on animals. Further research on longitudinal studies to better understand tick population dynamics and develop effective acaricides is encouraged. This called for collaborative control efforts among farmers, veterinarians and research institutions.

Acaricide resistance status of deltamethrin and coumaphos in Hyalomma anatolicum ticks collected from different districts of Haryana

To study the acaricide resistance status and possible mechanisms of action in conferring resistance to commonly used acaricides (deltamethrin and coumaphos), Hyalomma anatolicum ticks were collected from 6 dairy farms of Hisar and Charkhi Dadri districts of Haryana. By using standard larval packet test, H. anatolicum tick larvae of Charkhi Dadri isolates were found to be susceptible (100% mortality) to both the acaricides. Level-I resistance against coumaphos was recorded from four isolates, whereas, level-II was observed in only one isolate, collected from Hisar. One isolates (Kaimri) from Hisar also showed level-I resistance against deltamethrin. Biochemically, the ticks having higher values of resistance factor (RF) against coumaphos were found to possess increased enzymatic activity of α-esterase, β-esterase, glutathione-S-transferase (GST) and mono-oxygenase enzymes, whereas, the monoamine oxidase did not show any constant trend. However, the RF showed a statistical significant correlation with GST only. Native PAGE analysis of H. anatolicum ticks revealed the presence of nine types of esterases (EST-1 h to EST-9 h) by using napthyl acetate as substrate. In the inhibitory assay, esterases were found to be inhibited by PMSF, indicating the presence of serine residue at catalytic triad. The partial cds of carboxylesterase and domain II of sodium channel genes were sequenced to determine any proposed mutations in resistant isolates of H. anatolicum ticks, however, no mutations were observed in either gene, indicating that increased expression of detoxification enzymes as a possible mechanism for resistance development, in the current study.

Prevalence and associated risk factors of ixodid tick species infesting cattle and sheep in Balochistan, Pakistan

Tick infestation poses a serious threat to animal health, leading to significant losses in terms of vector-borne disease transmission, reduced live weight, lower quality hides, decreased milk production, and impaired reproduction in tropical and subtropical regions worldwide. This study aimed to determine the prevalence, seasonal variation, distribution pattern, and associated risk factors of Ixodid family tick species in the cattle and sheep population of three different districts in Balochistan, Pakistan. This study employed a convenient sampling method, collecting 4080 adult ticks from 816 cattle and sheep of various breeds, ages, and sexes. Specific morphological keys were used to identify the ticks up to the genus and species level. Among cattle, the highest prevalence was recorded for R. (B) annulatus (27.01%), followed by R. (B) microplus (24.02%), and H. anatolicum (20.54%). H. dromedarii (5.29%) was the least prevalent species observed in cattle. In the sheep population, H. anatolicum (30.34%) showed the highest prevalence, followed by H. marginatium (22.99%), and R. (B) annulatus (20.88%). H. dromedarii (6.96%) was the least prevalent species observed in sheep. The prevalence of R. (B) decoloratus, H. anatolicum and H. dromedarii was found to be significantly associated (P < 0.05) with the breed, age, and sex of both cattle and sheep. However, the presence of R. (B) annulatus, R. (B) microplus and H. marginatium tick species showed no significant association (P > 0.05) with these factors. In addition, the prevalence of ticks was higher in younger, female, and crossbred Friesian cattle compared to adults, males, and other breeds. Conversely, the prevalence of ticks was higher in adult, female and Hernai breed of sheep in the studied area. In conclusion, R. (B) annulatus and H. anatolicum are the dominant tick species infesting the cattle and sheep population in Balochistan. Consequently, this study provides valuable insights for developing practical and effective control measures against ticks and tick-borne diseases in the sheep and cattle population of Balochistan, Pakistan.

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

Alectorobius species are soft ticks primarily infesting birds, such as swallows, while Dermacentor species are hard ticks mainly infesting mammals, such as small ruminants. This study for the first time reported on the morphological and molecular bases of two tick species, namely A. coniceps and a Dermacentor sp. in Pakistan. The former species was examined in swallows' nests in Khyber Pakhtunkhwa province, while the latter species was examined in small ruminants in Balochistan province. In total, 25 ticks were collected, with 14 ticks morphologically identified as A. coniceps (males = 9 and females = 5) and 11 ticks identified as Dermacentor sp. (males = 7 and females = 4). Following morphological identification, molecular identification was gained by obtaining 16S rDNA and cox1 sequences for these ticks. The BLAST results for the 16S rDNA and cox1 sequences from A. coniceps shared a maximum identity of 97.46% and 96.49% with the same species from Malta. The BLAST analysis of the 16S rDNA and cox1 sequences from Dermacentor sp. showed maximum identities of 98.42% and 97.45% with Dermacentor pavlovskyi from China. The phylogenetic analysis based on 16S rDNA and cox1 of A. coniceps showed a close evolutionary relationship with the same species. The case of Dermacentor sp., based on 16S DNA and cox1, indicated a close evolutionary relationship with Dermacentor pavlovskyi from China.

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.

Molecular Detection of Rickettsia hoogstraalii in Hyalomma anatolicum and Haemaphysalis sulcata: Updated Knowledge on the Epidemiology of Tick-Borne Rickettsia hoogstraalii

Ticks are hematophagous ectoparasites that transmit pathogens to animals and humans. Updated knowledge regarding the global epidemiology of tick-borne Rickettsia hoogstraalii is dispersed, and its molecular detection and genetic characterization are missing in Pakistan. The current study objectives were to molecularly detect and genetically characterize Rickettsia species, especially R. hoogstraalii, in hard ticks infesting livestock in Pakistan, and to provide updated knowledge regarding their global epidemiology. Ticks were collected from livestock, including goats, sheep, and cattle, in six districts of Khyber Pakhtunkhwa (KP) Pakistan. Overall, 183 hosts were examined, of which 134 (73.2%), including goats (number = 39/54, 72.2%), sheep (23/40, 57.5%), and cattle (71/89, 80%) were infested by 823 ticks. The most prevalent tick species was Rhipicephalus microplus (number = 283, 34.3%), followed by Hyalomma anatolicum (223, 27.0%), Rhipicephalus turanicus (122, 14.8%), Haemaphysalis sulcata (104, 12.6%), Haemaphysalis montgomeryi (66, 8.0%), and Haemaphysalis bispinosa (25, 3.03%). A subset of 210 ticks was selected and screened for Rickettsia spp. using PCR-based amplification and subsequent sequencing of rickettsial gltA and ompB fragments. The overall occurrence rate of R. hoogstraalii was 4.3% (number = 9/210). The DNA of Rickettsia was detected in Hy. anatolicum (3/35, 8.5%) and Ha. sulcata (6/49, 12.2%). However, no rickettsial DNA was detected in Rh. microplus (35), Rh. turanicus (35), Ha. montgomeryi (42), and Ha. bispinosa (14). The gltA and ompB fragments showed 99-100% identity with R. hoogstraalii and clustered phylogenetically with the corresponding species from Pakistan, Italy, Georgia, and China. R. hoogstraalii was genetically characterized for the first time in Pakistan and Hy. anatolicum globally. Further studies should be encouraged to determine the role of ticks in the maintenance and transmission of R. hoogstraalii in different hosts.

Assessment of cypermethrin and amitraz resistance and molecular profiling of voltage-gated sodium channel and octopamine tyramine genes of Rhipicephalus microplus

Control of ticks and tick-borne pathogens is a priority for human and animal health. Livestock-holders extensively rely on acaricide applications for tick control. Different groups of acaricides including cypermethrin and amitraz have been consistently used in Pakistan. There has been a gap in understanding the susceptibility or resistance of Rhipicephalus microplus, the most prevalent tick in Pakistan, to acaricides. The present study aimed to molecularly characterize cypermethrin and amitraz targeted genes such as voltage-gated sodium channel (VGSC) and octopamine tyramine (OCT/Tyr) of R. microplus ticks in Khyber Pakhtunkhwa (KP), Pakistan to monitor the acaricides resistance. Tick specimens were collected from cattle and buffaloes in northern (Chitral, Shangla, Swat, Dir, and Buner), central (Peshawar, Mardan, Charsadda, Swabi, and Nowshera), and southern districts (Kohat, Karak, Lakki Marwat, Tank, and Dera Ismail Khan) of KP, Pakistan. Different concentrations of commercially available cypermethrin (10%) and amitraz (12.5%) were prepared for in vitro larval immersion tests (LIT). In LIT, the average mortality rate of immersed larvae was recorded that was increased gradually with an increase in the concentration of specific acaricide. The larvae's highest mortality rates (94.5% and 79.5%) were observed at 100-ppm of cypermethrin and amitraz, respectively. A subset of 82 R. microplus ticks was subjected to extract genomic DNA, followed by PCR to amplify partial fragments of VGSC (domain-II) and OCT/Tyr genes. The BLAST results of the consensus sequence of VGSC gene (domain-II) showed 100% identity with the acaricides susceptible tick sequence from the United States (reference sequence). Obtained identical sequences of OCT/Tyr genes showed maximum identity (94-100%) with the identical sequences reported from Australia (reference sequence), India, Brazil, Philippines, USA, South Africa, and China. Thirteen single nucleotide polymorphisms (10 synonymous and three non-synonymous) were observed at various positions of partial OCT/Tyr gene fragments. The SNP at position A-22-C (T-8-P) in OCT/Tyr gene has been linked to amitraz resistance in R. microplus ticks. Molecular analysis and LIT bioassay's findings indicate the availability of resistant R. microplus ticks in the KP region. To our understanding, this is the first preliminary study to monitor cypermethrin and amitraz resistance via molecular profiling of cypermethrin and amitraz targeted genes (VGSC and OCT/Tyr) in combination with in vitro bioassays (LIT) in R. microplus ticks from Pakistan.

Prevalence of different tick species on livestock and associated equines and canine from different agro-ecological zones of Pakistan

Ticks are ectoparasites that act as vectors for transmission of various pathogens to wild and domesticated animals and pose a serious threat to human health. Because of the hot and humid conditions in different agro-ecological zones of Pakistan, ticks are abundant and parasitize a variety of animals. The aim of this study was to identify different tick species and distribution on different hosts especially livestock, such as sheep, goat, cattle, buffalo, and camel, and livestock associated canines and equines, such as horse, donkey, and dog, across different agro-ecological zones of Pakistan. The ticks samples were collected and morphologically identified at genus and species level using morphological keys under stereomicroscope. A total of 2,846 animals were examined for the tick infestation, and 408 animals were tick-infested. Eleven tick species belonging to 4 genera were identified: Hyalomma anatolicum, Hyalomma scupense, Hyalomma dromedarii, Hyalomma isaaci, Rhipicephalus microplus, Rhipicephalus haemaphysaloides, Rhipicephalus turanicus, Haemaphysalis cornupunctata, Haemaphysalis montgomeryi, Haemaphysalis bispinosa, and Ixodes kashmiricus. The overall tick prevalence was 14.3%; host-wise infestation rate was 12.2% in sheep; 12.6%, goat; 11.7%, buffalo; 11.7%, cattle; 19.6%, camel; 27.4%, donkey; 23.5%, horse; and 24.3%, dog. Tick infestation of different animals differed on the basis of the zones. Camels showed the highest tick infestation rate in zones 1 and 2 (21.4 and 26.7%, respectively), whereas donkeys showed the highest infestation rate in zones 3, 4, 6, and 7 (25, 39.3, 3.3, and 21.4%, respectively). The infestation rates of Hyalomma and Rhipicephalus were the highest in zone 2 (71.4 and 52.9%, respectively). The infestation rate of Hyalomma was the highest (47.4%) in sheep; Haemaphysalis (46.9%), goat; Rhipicephalus (69.7%), buffalo; Rhipicephalus (62.3%), cattle; Hyalomma (70%), camel; Ixodes (60.9%), donkey; Ixodes (75%), horse; and Rhipicephalus (61.1%), dog. This study showed the diversity and infestation rate of different ticks with respect to their hosts and agro-ecological zones of Pakistan. High tick burdens and infestation rates are responsible for the spread of different tick-borne infections, resulting in loss of animal productivity and posing a threat to animal and human health. Understanding different tick species and their distribution across different zones will be helpful for developing efficient control strategies against different tick born infections.

The control of Hyalomma ticks, vectors of the Crimean–Congo hemorrhagic fever virus: Where are we now and where are we going?

At a time of major global, societal, and environmental changes, the shifting distribution of pathogen vectors represents a real danger in certain regions of the world as generating opportunities for emergency. For example, the recent arrival of the Hyalomma marginatum ticks in southern France and the concurrent appearance of cases of Crimean–Congo hemorrhagic fever (CCHF)—a disease vectored by this tick species—in neighboring Spain raises many concerns about the associated risks for the European continent. This context has created an urgent need for effective methods for control, surveillance, and risk assessment for ticks and tick-borne diseases with a particular concern regarding Hyalomma sp. Here, we then review the current body of knowledge on different methods of tick control—including chemical, biological, genetical, immunological, and ecological methods—and the latest developments in the field, with a focus on those that have been tested against ticks from the genus Hyalomma. In the absence of a fully and unique efficient approach, we demonstrated that integrated pest management combining several approaches adapted to the local context and species is currently the best strategy for tick control together with a rational use of acaricide. Continued efforts are needed to develop and implement new and innovative methods of tick control.

Disease-bearing Hyalomma ticks are an increasingly emerging threat to humans and livestock worldwide. Various chemical, biological, genetic, and ecological methods for tick control have been developed, with variable efficiencies. Today, the best tick control strategy involves an integrated pest management approach.

First genetic report of Ixodes kashmiricus and associated Rickettsia sp

Background

Hard ticks (Ixodidae) are hematophagous ectoparasites that transmit various pathogens to a variety of hosts including humans. Transhumant herds have been involved in the spread of ticks and associated Rickettsia spp., and studies on this neglected topic have been unexplored in many regions including Pakistan. This study aimed to investigate ticks infesting transhumant herds of sheep (Ovis aries) and goats (Capra hircus) in district Shangla, Khyber Pakhtunkhwa, Pakistan.

Methods

Of the 144 examined animals, 112 hosts (68 sheep and 44 goats) of transhumant herds were infested by 419 ticks of different life stages including nymphs (105; 25%), males (58; 14%) and females (256; 61%). For molecular analyses, DNA was extracted from 64 collected ticks and subjected to PCR for the amplification of tick 16S rDNA and ITS2 partial sequences and for the amplification of rickettsial gltA and ompA gene sequences.

Results

All tick specimens were identified as Ixodes kashmiricus based on morphological features. The obtained 16S rDNA and ITS2 sequences showed 95.7% and 95.3% identity, respectively, with Ixodes kazakstani reported from Kyrgyzstan. In the phylogenetic tree, the sequences clustered with members of the Ixodes ricinus species complex, including I. kazakstani and Ixodes apronophorus. Additionally, rickettsial gltA and ompA partial sequences were 99.7% identical to Rickettsia sp. endosymbiont of Ixodes spp. from Panama and Costa Rica and 99.2% with Rickettsia endosymbiont from the USA. Phylogenetically, the rickettsial gltA and ompA partial sequences from I. kashmiricus clustered with various haplotypes of Rickettsia endosymbiont, which were sister cladded to Rickettsia monacensis.

Conclusions

This is the first genetic report of I. kashmiricus and associated Rickettsia sp. Large-scale tick surveillance studies across the country are needed to investigate Ixodes ticks and associated pathogens.

Graphical Abstract

Participatory appraisal for healthcare and welfare management strategies of donkeys (Equus ascinus) in Balochistan, Pakistan

In spite of the significant importance of the donkeys (Equus ascinus) as draft animal in resource-poor countries like Pakistan, they are equines not receiving the appropriate care. They face challenges including injuries, diseases, lack of basic environment and mismanagement by their owners. The present study aims to provide a brief update on the current status of management of healthcare and the welfare of domestic donkeys using participatory epidemiological tools. These tools can help to provide better strategies for improving their productivity and inclusion in human society. This study was mainly focused only on donkeys and horses, mules and ponies were excluded from the study. We carried out a systematic review of the relevant available published literature and shortlisted 50 articles reporting on the different health related characteristics of donkeys. A comprehensive questionnaire was completed by 191 donkey owners, including nine farriers (all men, average age = 38.24 ± 12.43) over a time span from October 2021 to March 2022. Multivariate Odds Ratios (MORs) and 95% confidence intervals were used to assess the predictions of health management and welfare measures for the surveyed donkeys. The most common observed medical problems in donkey health were hyperlipaemia (28.06%), lameness (16.33%) and dental (20.41%) problems. One-third (34.31%) of the donkeys were underweight. The dull donkey with poor appetite needs a clinical emergency owing to a high risk of developing hyperlipemia, which may be life-threatening. These findings are quite useful for the improvement of healthcare management and the welfare of donkeys.

Spatio-Temporal Patterns of Ticks and Molecular Survey of Anaplasma marginale, with Notes on Their Phylogeny

Hard ticks (Ixodida: Ixodidae) are medically important ectoparasites that feed on all classes of terrestrial vertebrates. Recently, we molecularly characterized hard ticks and associated Anaplasma spp. in the northern and central regions of Khyber Pakhtunkhwa (KP), Pakistan; however, this knowledge was missing in the southern regions. This study aimed to investigate tick prevalence, host range, genetic diversity, and molecular survey of Anaplasma spp. in a wide range of tick species in two distinct physiographic regions of southern KP. A total of 1873 hard ticks were randomly collected from 443/837 hosts (cattle, Asian water buffaloes, horses, goats, sheep, dogs, and camels) in Lakki Marwat, Bannu, and Orakzai districts of KP. Overall, 12 tick species were morphologically identified, among which Hyalomma dromedarii was the most prevalent species (390/1873, 20.9%), followed by Hy. anatolicum (294, 15.7%), Rhipicephalus microplus (262, 14%), Hy. scupense (207, 11.1%), R. sanguineus (136, 7.3%), R. turanicus (121, 6.5%), Haemaphysalis cornupunctata (107, 5.7%), R. haemaphysaloides (110, 5.9%), Ha. montgomeryi (87, 4.6%), Hy. isaaci (58, 3.1%), Ha. bispinosa (54, 2.9%), and Ha. sulcata (47, 2.5%). The extracted DNA from a subset of each tick species was subjected to PCR to amplify cox1 or 16S rRNA sequences of ticks and 16S rRNA sequences of Anaplasma spp. The tick cox1 sequences showed 99–100% identities with the sequences of the same species, whereas 16S rRNA sequences of R. turanicus, Ha. montgomeryi and Ha. sulcata showed 97–100% identities with the corresponding species. The 16S rRNA sequence of Ha. cornupunctata showed 92% identity with the species from the same subgenus, such as Ha. punctata. The 16S rRNA sequence of Anaplasma spp. showed 100% identity with Anaplasma marginale. Moreover, 54 ticks were found positive for A. marginale with a total infection rate of 17.2%. The highest infection rate was recorded in Hy. dromedarii (31.1%) and the lowest in each R. haemaphysaloides and R. sanguineus (20%). All the cox1 or 16S rRNA sequences in phylogenetic trees clustered with the same species, except Ha. cornupunctata, which clustered with the Ha. (Aboimisalis) punctata. In this study, Ha. cornupunctata was reported for the first time at the molecular level. The genetic characterization of ixodid ticks and molecular detection of associated A. marginale will assist in the epidemiological surveillance of these parasites in the region.

Molecular Characterization and Assessment of Risk Factors Associated with Theileria annulata Infection

Simple Summary

Theileria is the tick-borne disease-causing agent responsible for theileriosis in various animals. Like other tick-borne pathogens, the epidemiology, associated risk factors and genetic diversity of Theileria spp. have mostly remained unexplored in the region. The current study was designed to analyze the epidemiology, associated risk factors, and molecular characterization of Theileria spp. in the selected districts of Khyber Pakhtunkhwa, Pakistan. Among the chosen districts, the highest infection was found in Upper Dir, while the most prevalent species was Theileria annulata clustered with sequences for the same species reported from Pakistan, China, and Italy. The risk factors associated with Theileria infection included age, gender, breeds, feeding system, hygienic measure, farming system, stall system, and seasons. The microscopic examination, in combination with the molecular approach, will enhance the early diagnosis and accurate identification of Theileria spp. and facilitate effective control strategies against these parasites.

Abstract

Theileria annulata is a tick-associated parasite that causes tropical theileriosis in livestock and is responsible for huge economic losses. Studies have been neglected on the effect of Theileria spp. on cattle in Khyber Pakhtunkhwa (KP), Pakistan. The present study was designed to determine the genetic diversity and assess the risk factors associated with Theileria infection in selected districts of KP. Information on the risk factors related to the Theileria infection was collected through a questionnaire. Blood samples were collected from symptomatic cattle from January 2019 to February 2020, identified morphologically through microscopic examination, and processed for molecular characterization using the 18S rRNA gene as a genetic marker. Of the 555 cattle examined (136, 24.5%) and (294, 53%) were found positive for Theileria spp. by microscopic examination and a PCR test, respectively. Based on the PCR test, the highest prevalence of infection was found in district Upper Dir (46/75, 61.3%), followed by Lower Dir (54/90, 60%); Malakand (51/88, 57.9%); Peshawar (40/80, 50%); and Charsadda (52/112, 46.4%), with the lowest in Bajaur (51/110, 46.34%). A BLAST analysis of the 18S rDNA sequences showed 99.5% identity with T. annulata . In a phylogenetic tree, the 18S rDNA sequence of T. annulata clustered with sequences from Pakistan, China, and Italy. A significant association was observed between the prevalence of infection and different host characteristics. The highest infection was found in adult cattle (216/360, 60%); females (218/377, 57.8%); and Holstein Friesian (120/180, 66.6%). Theileria infection was significantly associated with management practices. Higher infection rates were observed in free-grazing cattle (190/412, 42.2%); those kept in unhygienic conditions (246/405, 60.7%); cattle in combined farming systems (165/255, 64.8%); and those in congested stall systems (150/218, 68.8%). Seasonal patterns were found to be significantly associated with infection, and a higher infection rate was observed in summer (215/350, 61.4%) than in winter (79/205, 38.5%). Identified risk factors should be considered in designing practical control approaches to reduce the burden of Theileria infection. Large scale studies are required to explore the diversity of Theileria species in KP, Pakistan.

Acaricides Resistance in Ticks: Selection, Diagnosis, Mechanisms, and Mitigation

Ticks are blood-feeding ecto-parasites that have a cosmopolitan distribution in tropical and subtropical regions of the world. Ticks cause economic losses in the form of reduced blood, meat and dairy products, as well as pathogen transmission. Different acaricides such as organochlorines, organophosphates, formamidines (e.g. amitraz), synthetic pyrethroids, macrocyclic lactones, fipronil, and fluazuron are currently used sequentially or simultaneously to control tick infestations. Most acaricide treatments now face increasingly high chances of failure, due to the resistance selection in different tick populations against these drugs. Acaricide resistance in ticks can be developed in different ways, including amino acid substitutions that result in morphological changes in the acaricide target, metabolic detoxification, and reduced acaricide entry through the outer layer of the tick body. The current literature brings a plethora of information regarding the use of different acaricides for tick control, resistance selection, analysis of mutations in target sites, and resistance mitigation. Alternatives such as synergistic use of different acaricides, plant-derived phytochemicals, fungi as biological control agents, and anti-tick vaccines have been recommended to avoid and mitigate acaricide resistance. The purpose of this review was to summarize and discuss different acaricides applied for tick control, their mechanisms of action and resistance selection, genetic polymorphisms in their target molecules, as well as the approaches used for diagnosis and mitigation of acaricide resistance, specifically in Rhipicephalus microplus ticks.

Ornithodoros (Pavlovskyella) ticks associated with a Rickettsia sp. in Pakistan

Background

Soft ticks (Ixodida: Argasidae) are medically important ectoparasites that mainly feed on birds and mammals, which play a key role in their geographic distribution and dispersion. Despite their importance, studies on soft ticks are scarce for many regions and countries of the world, including Pakistan.

Methods

In this study, 2330 soft ticks—179 larvae (7.7%), 850 nymphs (36.4%), 711 males (30.5%) and 590 females (25.3%)—were collected from animal shelters in 18 locations within five districts of Khyber Pakhtunkhwa, Pakistan. A subset of the collected ticks was processed for DNA extraction and polymerase chain reaction (PCR) for the amplification of tick 12S ribosomal DNA (rDNA), 16S rDNA and cytochrome c oxidase subunit I (cox1), and rickettsial 16S rDNA gene fragments. The obtained sequences were used for the construction of a phylogenetic tree.

Results

All the specimens were morphologically identified as Ornithodoros, and were morphologically similar to Ornithodoros tholozani. The genus was confirmed by sequencing partial 12S rDNA, 16S rDNA and cox1 gene fragments. Additionally, a Rickettsia sp. was detected in some of the collected ticks by PCR targeting 16S rDNA. The morphological relatedness of the tick specimens with O. tholozani was confirmed by phylogenetic analysis, in which the Ornithodoros sp. clustered with Ornithodoros tholozani and Ornithodoros verrucosus, both of which belong to the subgenus Pavlovskyella and have been previously reported from Israel, Ukraine and Iran. The phylogenetic tree also indicated that the Ornithodoros sp. from Pakistan corresponds to an undetermined species. Furthermore, the associated Rickettsia sp. grouped with the limoniae group of Rickettsia species previously reported from Argas japonicus ticks from China.

Conclusions

This is the first molecular study of an Ornithodoros species from Pakistan. Further studies are essential to confirm its identity and possible pathogenicity with regard to its associated microorganisms in the studied region.

Graphical abstract

The Associated Decision and Management Factors on Cattle Tick Level of Infestation in Two Tropical Areas of Ecuador

Decision-making on tick control practices is linked to the level of knowledge about livestock farming and to the social context in which individuals practice them. Tick infestation is one of the main problems in tropical livestock production. The objective of this study was to characterize tick-control related practices in two tropical livestock areas and their potential association with the level of tick infestation. A total of 139 farms were included in this survey. To determine this association, a multivariate logistic regression model was used. A stepwise model selection procedure was used and model validation was tested. Cattle husbandry as a main activity, the use of external paddocks, the use of amitraz, and the lack of mechanization on the farm were related with high tick infestation. On the other hand, owner involvement in the preparation of acaricide solution was identified as a protective factor against high tick infestation. At animal level, age (old), body condition status (thin), and lactation were also associated with high tick infestations, while Bos primigenius indicus cattle and their crosses reduced the probability of high tick infestations. The factors studied, such as herd size, education level of the owners, and veterinary guidance, varied from farm to farm. Nonetheless, these differences did not generate changes in the level of tick infestation. According to the area under the receiver operating characteristic curve (AUC-ROC), the model at farm level predicts a high level of infestation, with an accuracy of 72.00% and high sensitivity. In addition, at animal level, crossbreeding with indicus cattle and breeding selection for host resistance will be useful against high tick infestation. Likewise, the implementation of programs of capacitation and research on tick control for farmers, cowboys, and vets in these areas is necessary.

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

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.

Risk factors associated with tick infestations on equids in Khyber Pakhtunkhwa, Pakistan, with notes on Rickettsia massiliae detection

BACKGROUND

Studies on ticks infesting equids are lacking in various parts of the world, including Khyber Pakhtunkhwa (KP), Pakistan. The aim of this study was to investigate the diversity of ticks infesting equids, associated risk factors and rickettsial detection in ticks from equids in KP.

METHODS

Inspection of 404 equid hosts from November 2018 to October 2019 resulted in the collection of 550 ticks. Data on tick-associated risk factors were collected from equid owners by means of a questionnaire. After morphological identification, partial DNA sequences of the tick mitochondrial 16S rRNA gene were used for taxonomic confirmation of species. Partial sequences of the gltA and ompA genes were used for Rickettsia detection in ticks.

RESULTS

A total of 550 tick specimens were collected on 324 (80.2%) of the equids inspected, of which 161 were horses (50%), 145 (45%) were donkeys and 18 were mules (5%). The ticks were identified as belonging to the following five species: Rhipicephalus microplus (341 specimens, 62% of the total ticks), Rh. haemaphysaloides (126, 23%), Rh. turanicus (39, 7%), Rh. sanguineus (s.l.) (33, 6%) and Hyalomma anatolicum (11, 2%). The most prevalent tick life stage was adult females (279, 51%) followed by adult males (186, 34%) and nymphs (85, 15%). Higher tick infestations were observed on male equids (relative risk [RR] 0.7432, P < 0.0005) and adult equids (RR 1.268, P < 0.0020). Ticks were frequently attached to the axial region of horses (55, 21%), sternum of donkeys (44, 21%) and belly of mules (19, 23%) (P < 0.04). Temporal patterns of tick infestation in association with temperature and humidity were highly significant (P < 0.05). Risk factors, such as animal housing (P < 0.0003), living management (P < 0.006), grazing type (P < 0.01) and location in hilly areas (P < 0.02), significantly enhanced the chances for tick infestation. Tick species analyzed in this study were phylogenetically related to species from Afghanistan, China, South Africa and Taiwan. Partial sequences of the gltA and ompA genes obtained from Rh. microplus and Rh. haemaphysaloides were 100% identical to the spotted fever group pathogen Rickettsia massiliae.

CONCLUSIONS

Equids exposed to significant risk factors were infected by one or more of at least five tick species in KP, Pakistan, and some of the ticks harbored the human pathogen R. massiliae.

Life Cycle and Genetic Identification of Argas persicus Infesting Domestic Fowl in Khyber Pakhtunkhwa, Pakistan

Ticks transmit numerous pathogens to animals including humans; therefore, they are parasites of health concern. Soft ticks infesting domestic fowl in Pakistan are carriers of viruses and bacteria and cause unestimated economic losses in the poultry sector. The current study was intended to identify soft ticks infesting domestic fowl and understand their spatiotemporal distribution along 1 year. A sum of 7,219 soft ticks were collected from 608 domestic fowl in 58 infested shelters; 938 (12.9%) ticks were found on the host and 6,281 (87%) in the shelters. The collected ticks comprised 3,503 (48.52%) adults including 1,547 (21.42%) males and 1,956 (27.09%) females, 3,238 (44.85%) nymphs, and 478 (6.62%) larvae. The most prevalent life stages were adults, followed by nymphs and larvae. Overall tick prevalence considering all visited shelters was 38.66% (58/150). The highest tick prevalence was found in district Lakki Marwat (50.03%) followed by Peshawar (31.08%) and Chitral (18.88%) districts. All ticks were morpho-taxonomically identified as Argas persicus. To determine their life cycle, adult A. persicus were reared in the laboratory infesting domestic fowl (Gallus gallus domesticus). The life cycle was completed in 113–132 days (egg to egg) with a mean temperature of 33 ± 3°C and relative humidity of 65 ± 5%. Individual ticks were used for DNA extraction and subjected to polymerase chain reaction (PCR) using specific primers for the amplification of a partial fragment of mitochondrial cytochrome oxidase subunit I (cox1) and 16S ribosomal RNA (16S rRNA) genes. Obtained amplicons were compared using basic local alignment search tool (BLAST) to scan for homologous sequences. Phylogenetic trees showed A. persicus from Pakistan clustering with conspecific sequences reported from Australia, Chile, China, Kenya, and the United States. This is the first study aiming to reproduce the life cycle of A. persicus and genetically identify this tick in the region. Further studies are encouraged to investigate the pathogens associated with this soft tick species in Pakistan.