Studies on theileriosis in goats from Karnataka, South India

Identification, molecular characterization and risk factors of Theileria infection among sheep: a first comprehensive report from North India

The present study was aimed at the identification, molecular characterization, and risk factor assessment of Theileria infection among sheep of Haryana province, north India. A total of 402 blood samples were collected from three different climatic zones of Haryana from March 2020 to September 2021. Light microscopy of blood smears revealed Theileria spp. infection in 47.26% (n = 190), while 60.94% (n = 245) of blood samples were positive using nested PCR. Extensive molecular characterization of Theileria infection using four pairs of species-specific primers indicated the dominance of T. ovis (29.1%) followed by T. lestoquardi (12.69%), T. luwenshuni (5.97%) and T. annulata (1.49%). Mixed infection was detected in 11.69% of cases. Bidirectional sequencing and phylogeny further confirmed the presence of these four Theileria spp. in the investigated area under study. Hematology indicated a significant (p < 0.01) reduction in various haematological indices of animals infected with T. luwenshuni and T. lestoquardi compared to the healthy control group. Risk factors like age, sex, and zone were significantly associated with Theileria infection in sheep. The present investigation depicts the first comprehensive molecular report of ovine Theileria spp., which warrants further study to develop suitable control strategies against these haemoparasitic infections.

Molecular identification and genetic characterization of Theileria and Anaplasma infection in sheep and goat of North Gujarat, India

Hemoprotozoal diseases are significant health concerns in small ruminants. The present study was conducted to identify and characterize the species of Theileria and Anaplasma in sheep and goats located in different districts of North Gujarat, India. A total of 226 (Banaskantha = 175, Patan = 26, and Bhuj = 25) blood samples were collected from sheep (n = 78) and goats (n = 148), and 46 ticks were collected and identified from sheep and goats. PCR assays were carried out using genus and species-specific primers for Theileria targeting 18S rRNA locus and for Anaplasma targeting the msp5 gene. Overall, 37.2% sheep (29/78) and 10.8% of goats (16/148) were positive for Theileria by PCR, whereas 15.4% of sheep (12/78) and 25.7% goats (38/148) were positive for Anaplasma infection. Moreover, mixed infection was found in 4.4% (10/226) of sheep and goats by PCR. Sanger sequencing of Theileria and Anaplasma positives revealed a high similarity to T. ovis and A. ovis using NCBI blast, respectively. Phylogenetic analyses revealed that the Anaplasma spp. DNA sequences belonged to the A. ovis group and closely associated with the A. ovis nucleotide sequence strain Haibei isolated in China from sheep (GQ483471). The phylogenetic analysis based on the SSU rRNA locus revealed that the Theileria ovis DNA sequences belonged to the T. ovis group and closely related to MW440586 isolated in Kerala, India, from a goat. The majority of ticks (91.3%) were identified as Hyalomma. In conclusion, Theileria ovis and Anaplasma ovis were commonly identified species in sheep and goats and transmitted mainly by Hyalomma ticks in North Gujarat, India, which is important baseline data for future research and control strategies. This is the first report on Theileria and Anaplasma co-infections in sheep and goats from North Gujarat, India.

Molecular Detection and Differentiation of Different Theileria Species in Naturally Infected Goats Using Nested PCR-RFLP: A First Report from Northern India

PURPOSE

Theileriosis is an economically important tick-borne pathogen with a serious impact on livestock health and productivity. Despite the fact that bovine theileriosis has been widely investigated, there exists a paucity of information on these infections in small ruminants, especially in India. The present study was carried out to detect and differentiate different Theileria spp. in goats using nested PCR RFLP.

METHODS

Blood samples and ticks were collected from 405 goats in various agro-climatic zones of Haryana state, India. The blood samples were screened by microscopy, nested PCR-RFLP, and sequence analysis. The nested PCR-RFLP was performed with four restriction enzymes viz., Hpa II, Bsh 1285I, Hae II and Rsa I. Six nested PCR amplicons with different RFLP patterns were sequenced and submitted to NCBI (OM666861, MZ220430, OM666628, MZ220437, OM666637, OM721806).

RESULTS

Microscopy revealed 18.27% (n = 74) infection with Theileria spp., while 33.58% (n = 136) of blood samples were confirmed positive by nested PCR. Out of 136 positive samples, 43.38% (n = 59), 11.02% (n = 15) and 20.58% (n = 28), were positive for T. ovis, T. lestoquardi and T. luwenshuni (Theileria sp. China 1), respectively. Mixed infection was detected in 25% (n = 34) cases. Based upon Hpa II digestion pattern, 13 samples with T. lestoquardi and T. ovis, and 21 samples with T. ovis and T. luwenshuni were detected. Sequence study further confirmed their identity. The majority of ticks collected from goats were identified as Rhipicephalus spp., Hyalomma anatolicum and Hemaphysalis spp.

CONCLUSION

This study represents the first confirmed molecular report of goats infected with T. ovis, T. lestoquardi, and T. luwenshuni from northern India.

Molecular identification of Theileria species in naturally infected sheep using nested PCR-RFLP

Ovine theileriosis is an important tick-borne haemoprotozoan disease of sheep in tropical and subtropical regions, causing severe productivity and economic loss. There is a paucity of information related to molecular studies of ovine theileriosis from India. The present study identified different Theileria spp. in naturally infected sheep using nested PCR-restriction fragment length polymorphism (nPCR-RFLP). Blood samples and ticks were collected from 204 sheep in different agro-climatic zones of Haryana state, India, during the tick active season. Microscopic examination of thin blood smears revealed 33.3% (68/204) infections with Theileria spp., while 44.6% (91/204) of blood samples were positive by nPCR assay. Different Theileria spp. were identified based upon RFLP patterns using four restriction enzymes: Hpa II, Bsh 1285I, Hae II and Rsa I. Out of 91 positive samples, 50.5% (46/91), 23.08% (21/91), 11% (10/91) and 2.2% (2/91) were positive for T. ovis, T. lestoquardi, T. luwenshuni (Theileria sp. China 1/Theileria sp. China) and T. annulata, respectively. Mixed infection was detected in 13.2% (12/91) of cases. Based upon HpaII enzymatic digestion pattern, two samples with T. lestoquardi and T. annulata, nine samples with T. lestoquardi and T. ovis and one sample with T. ovis and T. annulata were detected. The presence of these Theileria spp. was further confirmed by sequence analysis. The majority of ticks collected from sheep were identified as Rhipicephalus spp. followed by Hyalomma anatolicum and Hemaphysalis spp. The present investigation depicts the first comprehensive molecular report of naturally infected sheep with T. ovis, T. lestoquardi, T. annulata and T. luwenshuni from northern India.

Identification of Theileria spp. and investigation of hematological profiles of their infections in goats in Hainan Island, China

Theileria spp. are a group of parasites primarily transmitted by ticks and can pose a significant threat to domestic and wild animals globally. The main objective of this study was to understand the epidemiology of Theileria spp. in goats of Hainan Island/province, which is the only tropical region of China, and to study their hematological profiles in naturally infected goats. A total of 464 blood samples were collected from randomly selected local adult goats (Capra hircus, local domestic breed with black hair), from six cities and eight counties of Hainan, from November 2017 to October 2020. Blood smear microscopy of the sample and a nested polymerase chain reaction (nPCR) targeting the 18S rRNA gene combined with DNA sequencing were used to detect piroplasm infections in goats. Data analysis of the obtained sequences revealed that all the sequences were highly similar to the Theileria luwenshuni 18S rRNA gene sequence from the database. This result is consistent with the microscopic examination. In the hematological test, hematocrit, mean corpuscular volume, and mean corpuscular hemoglobin of the goats naturally infected with T. luwenshuni significantly increased, while mean corpuscular hemoglobin concentration and red blood cell distribution width (RDW) were significantly decreased. Results showed that T. luwenshuni could cause macrocytic, hypochromic anemia in goats. This study provides reliable and comprehensive information about the epidemiology of the parasite infections and hematological profile of the infected goats in Hainan, which encourages further investigations to develop practical control strategies for Theileria spp. infections in tropical areas.

Molecular Epidemiology and Characterization of Theileria in Goats

The study was carried out to determine the prevalence and associated risk factors of theileriosis in goats of Chattogram district, Bangladesh. Molecular characterization of circulating Theileria in this area was also undertaken. A total of 400 samples were collected from goats of different breeds, ages and sex with relevant information of rearing and management. The prevalence of theileriosis was 8.50% (34/400) by polymerase chain reaction though all of those samples were test-negative by microscopic examination. Among different risk factors season, breed and tick infestation were found to be significantly (p ≤ 0.05) associated with the prevalence of theileriosis in goats. Serous nasal discharge and swollen lymph nodes were determined to be significant clinical signs. The Theileria spp. detected in the present study closely resemble isolates which were previously detected in Myanmar and China. Further large scale epidemiological studies are required to identify the circulating species and responsible vectors, which would facilitate control measures for this disease in Bangladesh.

MOLECULAR CHARACTERIZATION OF THEILERIA SPP. IN GOATS FROM SHAANXI PROVINCE, NORTHWESTERN CHINA

Theileriosis is an important tick-borne pathogen of livestock globally, causing severe reduction of livestock productivity and economic loss. To systematically investigate the prevalence and species of Theileria spp. in goats from Shaanxi province, a total of 509 blood samples were collected from dairy, cashmere and meat goats from 7 counties, and examined by using the microscopic examination and the nested PCR targeting the SSU rRNA gene. Of them, 268 (52.7%, 268/509) were positive for Theileria infection. The prevalence was closely associated with ages and production categories. The highest infection was found in meat goats of 7 to 12-months, and lowest was detected in cashmere goats of 3 to 6 months. Sequence analysis indicated the presence of 2 Theileria species, with Theileria luwenshuni as the prevalent species and the first report of Theileria sp. OT3 in goats in China. These findings indicated the wide distribution of Theileria spp. in goats of Shaanxi province, and would shed new light on the distribution of this parasite in China.