Prevalence of Theileria annulata infection in Hyalomma anatolicum anatolicum in Punjab state, India

Epidemiology and molecular characterization of Theileria annulata in ticks collected from cattle in the central part of Tamil Nadu, India

Tick-borne diseases are the most common in cattle in the tropical and subtropical regions of India and lead to substantial economic losses to small and marginal farmers. This study aimed to identify the diverse species of ticks infesting cattle in the central part of Tamil Nadu, India, and to assess the prevalence of Theileria annulata infection in various species of ticks through PCR. Out of 123 cross-bred and 105 native breed cattle examined for tick infestation, 40 (18%) and 29 (12.7%) cattle were infested with Ixodid ticks, respectively. The most prevalent tick species identified was Rhipicephalus microplus (n=589), followed by Hyalomma anatolicum (n=532), Hyalomma marginatum (n=145), Haemaphysalis intermedia (n=79), and Rhipicephalus haemophysaloides (n=1) found in the study area. The prevalence and intensity of the tick infestation were found to be higher in cross-bred (71.04%) than native breed cattle (28.96%), and there was no significant difference between the studied breeds (chi-square value =24; df =20; p value =0.24) was observed. However, a significant difference in the H. anatolicum tick infestation was observed between the Cauvery Delta (14.30%) and the North-Western (20%) zones of Tamil Nadu (p<0.05). DNA fragments of 193 bp derived from 18S rRNA gene sequences of T. annulata were amplified using species-specific primers. Of these, 16 out of 37 (43.2%) and 10 out of 39 (29%) pooled samples of H. anatolicum and 4 out of 18 (22.2%) and 1 out of 5 (20%) pooled samples of H. marginatum were found positive for T. annulata from the Cauvery Delta and North-Western zones, respectively. R. microplus, H. intermedia, and R. haemaphysaloides from these regions were negative. These findings confirm that H. anatolicum (52.17%) is the predominant vector for T.annulata rather than H. marginatum (18.84%), and the PCR is a useful method of determining the infection rates in ticks collected from animals carrying low levels of T. annulata piroplasms.

Guardians of the Herd: Molecular Surveillance of Tick Vectors Uncovers Theileriosis Perils in Large Ruminants

Theileria sp. (Piroplasmida: Theileriidae) is one of the most widely known infections transmitted by hard ticks (Acari: Ixodidae) and has been linked to significant economic losses across the globe. The study's main emphasis was theileriosis, a disease that is common in Pakistan and has an incidence ranging from 0.6% to 33%. Through DNA screening of the vector ticks and host blood, this study sought to determine the risk of tick-borne theileriosis in populations of buffalos (Bubalus bubalis) and cattle (Bos indicus) in Toba Tek Singh district of Punjab, Pakistan. Identified tick species include Hyalomma anatolicum (35.4%), Rhipicephalus (Boophilus) microplus (30.2%), and R. sanguineus (25%). Tick specimens were collected from animals and their respective microenvironments. PCR assays targeting Theileria annulata were used to investigate the infection in the DNA extracted from the collected blood samples from large ruminants and salivary glands (SGs) of the Hyalomma ticks. The 18S rRNA of T. annulata was amplified using specific primers. Positive T. annulata amplicons were sequenced and verified using BLAST analysis. Overall, 50% of SGs contained T. annulate DNA. Female ticks, and those collected from cattle and from riverine environments had significantly higher (p < 0.05) rates of Theileria infection in their acini. Overall prevalence of Theileria infection was 35.9% in blood collected from large ruminants. Cattle had a substantially greater frequency of bovine theileriosis (43.2%) than buffalos (28.7%). Age and sex of large ruminants were significantly positively associated (p < 0.05) with Theileria infection. Furthermore, compared to non-riverine cattle (35%) and buffalo (19.5%), riverine cattle (52.2%) and buffalo (36.2%) showed a considerably higher prevalence. The results of this study, which is the first in Pakistan to examine the blood of large ruminants and vectorial function of Ixodid ticks in the transmission of T. annulata along with associated risk factors, offer an important insight for risk assessment of Theileria infection in livestock using vectorial infectivity.

Cytauxzoon felis in salivary glands of Amblyomma americanum

Cytauxzoon felis is a tick-borne piroplasmid hemoparasite that causes life-threatening disease in cats. Despite the critical role that ticks play in pathogen transmission, our knowledge regarding the C. felis life cycle remains limited to the feline hosts. Specific life stages of C. felis within the tick host have never been visualized microscopically and previous investigations have been limited to molecular detection by polymerase chain reaction (PCR). Sporozoites are the infectious stage of piroplasmids that are transmitted by ticks. In other tick-borne piroplasmids, sporozoite-based vaccines play a key role in disease prevention and management. We believe sporozoites have similar potential for cytauxzoonosis. Therefore, the objective of this study was to use different molecular and microscopic techniques to detect and evaluate C. felis sporozoites in tick salivary glands (SG). A total of 140 Amblyomma americanum adults that were fed on C. felis-infected cats as nymphs were included for this study. Specifically, dissected SGs were quartered and subjected to C. felis RT-PCR, RNAscope® in situ hybridization (ISH), histology, direct azure staining, and transmission electron microscopy (TEM). Cytauxzoon felis RT-PCR was also performed on half tick (HT) carcasses after SG dissection. Cytauxzoon felis RNA was detected in SGs of 17/140 ticks. Of these, 7/17 ticks had microscopic visualization via ISH and/or TEM. The remaining 10/17 ticks had only molecular detection of C. felis in SGs via RT-PCR without visualization. Cytauxzoon felis RNA was detected solely in HT carcasses via RT-PCR in 9/140 ticks. In ISH-positive tick SGs, hybridization signals were present in cytoplasms of SG acinar cells. TEM captured rare C. felis organisms with characteristic ultrastructural features of sporozoites. This study describes the first direct visualization of any developing stage of C. felis in ticks. Forthcoming studies should employ a combination of molecular and microscopic techniques to investigate the C. felis life cycle in A. americanum.

Molecular detection and characterization of Theileria sp. from hedgehogs (Paraechinus aethiopicus) in Saudi Arabia

In this study, we conducted molecular detection and characterization of piroplasms that infect the Ethiopian or desert hedgehogs (Paraechinus aethiopicus) in Saudi Arabia. Blood samples from 112 (68 males and 44 females) desert hedgehogs from Unaizah, Central Saudi Arabia were screened for Theileria/Babesia DNA using the polymerase chain reaction (PCR) employing specific primers amplifying the partial 18S small subunit rRNA gene. Theileria DNA was detected in 51 samples (45·5%), giving a prevalence of 45·5%. Theileria DNA was found in 33 (48·5%) males and 18 (40·9%) females, and there was no significant difference (P > 0·05) in the prevalence between males and females. Similarly, there was no significant difference (P > 0·05) in the prevalence between juveniles (40%) and adults (46·7%). There was a significant difference in the prevalence of Theileria in hedgehogs collected from May to September and the period from October to April (P = 0·003). Four haplotypes of Theileria sp. in hedgehogs were detected and designated as H1-H4. H1 was the predominant haplotype and found in 80·8% of the positive individuals. Partial sequences of the 18S rRNA of Theileria sp. from hedgehogs grouped with Theileria spp. that are benign. This study is the first report of the occurrence of Theileria spp. in Saudi Arabian desert hedgehogs.

Determining Theileria annulata parasitemia through qPCR in lactating cows of Odisha, - a theileriosis-endemic region of India

Study was undertaken in a theileriosis-endemic region of India during May 2018 to April 2019 among milch cows. Blood samples collected from apparently healthy (n = 65) and Theileria-suspect cows (n = 65) were screened against T. annulata and T. orientalis infection by SYBR Green‒based real time PCR using primers designed from the isolates of study area. Cows having single infection with T. annulata with/without clinical signs of inappetence, low milk yield, pale mucous membranes, fever, enlarged prescapular lymph node, soil licking, panting, coughing, salivation and lachrymation were subjected to further investigation where parasitaemia and piroplasms per 1000 erythrocytes ranged from 1.6 × 10⁷ to 1.2 × 10⁸ parasites/mL of blood and 3-24 piroplasms in moderate group (16/65), 4.4 × 10⁸ to 6.9 × 10⁹ parasites/mL of blood and >88 piroplasms in severe group (30/65) and 1.6 × 10⁴ to 5.5 × 10⁶ parasites/mL of blood and 0-1 piroplasms in asymptomatic or carriers (17/65), respectively. Study unfolded significant difference in T. annulata parasitaemia among apparently healthy and ill cows. Phylogenetic analysis of our T. annulata isolates (NCBI accession numbers MN098316, MN098317 and MN098318) exhibited maximum similarity with the isolates detected in other parts of India.

Prevalence of bovine tropical theileriosis in sub-Himalyan region of northern India

The prevalence of bovine tropical theileriosis (BTT) caused by Theileria annulata was studied in large ruminants of sub-Himalyan region of northern India using thin blood smear examination (TBE), polymerase chain reaction (PCR) and loop mediated isothermal amplification (LAMP) assays. About 11.04% blood samples were found positive for BTT. Maximum seasonal prevalence of BTT was observed in summer followed by rainy season and winter. Month-wise maximum prevalence was recorded in May and minimum in January. Laboratory examination with Giemsa staining for Koch’s blue bodies (KBB) and piroplasms revealed that 3.75% samples were positive for theileriosis. LAMP method gave the highest level of sensitivity followed by AS-PCR and TBE. Hence, it is suggested that LAMP can be a better molecular diagnostic tool for large scale epidemiological studies of bovine tropical theileriosis. Our results provide better understanding of this haemoprotozoan parasite and hence may help in devising timely control measures.

Determination of the Infectivity of Cryopreserved Theileria annulata Sporozoites in Tick Derived Stabilates Iran Ak-93 Strain, by In Vivo and In Vitro Methods

BACKGROUND

The protozoan parasite Theileria annulata is the causative agent of tropical theileriosis in cattle. Vaccination is recommended by administration of attenuated schizont-infected cell lines. The expected protective immunity post-vaccination can be demonstrated by challenge test through inoculation of highly virulent infective sporozoites. The aim of this study was to produce Hyalomma anatolicum anatolicum tick infected with T. annulata (local strain) for preparation of tick-derived sporozoite stabilates for molecular characterization and infectivity test assay.

METHODS

A local T. annulata strain was used for experimental infection of calves. A field isolate of H. a. anatolicum was isolated, laboratory-reared and infected by blood-feeding on Theileria infected above-mentioned calves. The infectivity of calf, tick and prepared stabilate were confirmed by clinical signs of theileriosis, microscopic inspection, RT-PCR and in vitro cell culture.

RESULTS

The tick stabilate was prepared and cryopreserved in liquid nitrogen. The infectivity of the tick stabilate was verified by in vivo bioassay, in vitro cell culture infection, microscopic inspection in salivary glands and RT-PCR assay. The in vitro produced cell line in this study was characterized by T. annulata Cytochrome b gene analyzing.

CONCLUSION

The infectivity of a new prepared tick-derived sporozoite stabilate was confirmed in susceptible calves; by microscopically, post mortem, tick microscopic and molecular assays. Moreover, naïve PBMCs were transformed and proliferated by T. annulata infected tick stabilate to immortal T. annulata schizont infected cell line. The potent infective sporozoite tick derived stabilate could be used for vaccine efficacy and challenge test as well as in vaccine development.

Molecular evidence of tick-borne pathogens in Hyalomma anatolicum ticks infesting cattle in Xinjiang Uygur Autonomous Region, Northwestern China

Although tick-borne pathogens have been widely reported in ticks in China, there is little information available on the prevalence of information in Hyalomma ticks from cattle. This study aims to determine the occurrence of pathogens in Hyalomma anatolicum collected from cattle in Xinjiang Uygur Autonomous Region, China, by PCR, sequencing and phylogenetic analysis. Borrelia burgdorferi s.s., Rickettsia massiliae and Anaplasma bovis were identified, whereas DNA of Ehrlichia species and an Anaplasma platys-like pathogen were also detected. Our findings highlight the risk of infection of animals and humans with these pathogens in north-western China.

Studies on alterations of clinical and hemato-biochemical parameters before and after treatment in calves naturally infected with theileriosis

Aim:

The aim was to determine hemato-biochemical alterations and to determine the better treatment of theileriosis in naturally infected calves.

Materials and Methods:

A total of 74 Holstein crossbred calves below 6 months of age, of either sex were included for present investigation in Bikaner. Based on the clinical examinations and laboratory results, 20 calves included for hemato-biochemical studies (before and after treatment) and divided into two groups (having 10 calves each).

Results:

The clinical examination of these calves revealed weakness, ticks infestations, high fever above 104°F, pronounced swelling of prescapular, prefemoral, parotid lymph nodes, loss of elasticity of skin, anemia, lacrimal discharges, pulpy cornea, tachycardia, and dyspnea. There was highly significant decrease (p<0.01) in hemoglobin, total erythrocyte count, packed cell volume and total leukocyte count, serum glucose, total protein, globulin and albumin level and highly significant increase in aspartate aminotransferase and alanine aminotransferase level as compared to healthy control animals in Group I and II. The animals of Group II treated with buparvaquone along with single blood transfusion shows better recovery then animals of Group I treated with bupavaqone and hematinic.

Conclusions:

Significant changes were found in hemato-biochemical parameters in theileria affected calves before treatment as compare to healthy control calves. Significant improvement was observed in hemato-biochemical parameters in buparvaquone and single blood transfusion treated calves as compare to another group, so it is concluded that buparvaquone and single blood transfusion is better combination for treatment of theileriosis.

Molecular epidemiology, risk factors and hematochemical alterations induced by Theileria annulata in bovines of Punjab (India)

Bovine tropical theileriosis, caused by Theileria annulata, is one of the economically important fatal tick borne haemoprotozoan diseases of dairy animals. The aim of present investigation was to map the distribution of T. annulata in bovines of Punjab state of India in relation to various risk factors including age, sex of animals, location and management of farms. In a cross sectional study, a total of 1278 blood samples were randomly collected from twenty districts falling in five major agro-climatic zones of Punjab. All the samples were screened by blood smear examination followed by polymerase chain reaction targeting SSU rRNA gene for Theileria spp. PCR positive samples (n = 386) for Theileria spp. were then analyzed for T. annulata by amplification of Tams1 gene. Overall prevalence of T. annulata was found to be 29.26% in Punjab, with highest in western Zone (40.49%, 95% CI = 35.57-45.41) and lowest in submountain zone (18.90%, 95% CI = 13.73-24.06). The propensity of incidence of T. annulata was found to be highest in cross bred cattle (32.40%, 95% CI = 29.87-34.94), followed by indigenous cattle (19.64%, 95% CI = 10.67-28.61) and buffaloes (19.2%, 95% CI = 14.99-23.41). Between the two sexes, incidence of T. annulata was higher in female animals. Calves less than 6 months of age were found to be more prone to theileriosis.

Prevalence of Theileria annulata infection in Hyalomma anatolicum anatolicum collected from crossbred cattle of Ludhiana, Punjab

The prevalence of Theileria infection in tick vector Hyalomma anatolicum anatolicum collected from healthy animals of Ludhiana district, Punjab was recorded to assess the natural infection level of theilerial parasite in the field condition. A total of 60 semi-engorged H. a. anatolicum were collected from cattle and their salivary glands were dissected out. One half of the salivary gland was stained with methyl green pyronin (MGP) and the other half was utilized for DNA isolation for molecular detection of Theileria infection. A PCR and nested PCR assays were standardized for the detection of T. annulata infection in salivary gland of H. a. anatolicum. The prevalence of T. annulata infection was recorded as 8.3, 20.0 and 60.0 % by MGP staining, primary PCR and nested PCR, respectively. Further, the prevalence was higher in female ticks (8.8 %) than male ticks (6.6 %). The results demonstrated that both primary and nested PCR assays are a valuable technique for detection of T. annulata infection in vector tick under field conditions.