Diversity and Genetic Structure of Theileria annulata in Pakistan and Other Endemic Sites

Cattle co-infection patterns by hemopathogens and their phylogenetic analysis during the tick season in Constantine and Mila, Northeast Algeria

Tropical theileriosis, babesiosis, and anaplasmosis are the most dominant tick-borne infections in North Africa where they cause significant economic losses in ruminants' industry. The aim of the present work was to study infections and co-infection patterns in 66 cattle with clinical signs of piroplasmosis and/or anaplasmosis in two localities, Beni Hamidene and Grarem Gouga, districts of Constantine and Mila (Northeast of Algeria), respectively. This study was conducted between early May and late September during four years 2017, 2018, 2020, and 2021. PCR showed that the most frequent pathogen in cattle with clinical signs of piroplasmosis and/or anaplasmosis was Theileria annulata (66/66; 100%) followed by Babesia bovis (21/66; 31.8%), Anaplasma marginale (15/66; 22.7%), and Babesia bigemina (3/66; 4.5%) (p < 0.001). Giemsa-stained blood smears examinations revealed that 66.7% (44/66); 10.6% (7/66); and 9.1% (6/66) of cattle were infected by T. annulata, Babesia spp., and A. marginale, respectively (p < 0.001). PCR revealed seven co-infection patterns: T. annulata/A. marginale (15/66; 22.7%), T. annulata/B. bovis (21/66; 31.8%), T. annulata/B. bigemina (3/66; 4.5%), T. annulata/A. marginale/B. bovis (7/66; 10.6%), T. annulata/B. bovis/B. bigemina (2/66; 3%), T. annulata/A. marginale/B. bigemina (1/66; 1.5%), and T. annulata/A. marginale/B. bigemina/B. bovis (1/66; 1.5%). Phylogenetic analyses showed that T. annulata Tams1 and B. bigemina gp45 sequences were identical to isolates from Mauritania and South Africa, respectively. The three A. marginale amplicons obtained herein had 99.63 to 99.88% similarity between them. This study provides data that can be used to improve control programs targeting these cattle hemopathogens.

Molecular epidemiology, associated risk factors, and phylogeny of Theileria annulata infecting buffaloes and cattle from different agro-climatic regions of Punjab, Pakistan

Background

Tropical theileriosis is the most prevalent hemoprotozoan disease in Pakistan.

Aims

The study aimed to investigate the epidemiology and evolutionary relationship of Theileria annulata in bovines in diverse agro-climatic regions of Punjab, Pakistan.

Methods

800 blood specimens were collected from asymptomatic cattle (n=480) and buffaloes (n=320) using a multistage sampling method from Sargodha (n=400) and Multan (n=400) districts. The samples were assessed for blood smear microscopy and cytochrome b gene based PCR. Twenty samples were collected from each union council of each district.

Results

The overall prevalence of T. annulata infection in bovines was 9% and 17.13% as determined by blood smear analysis and PCR, respectively. The disease positivity in cattle and buffaloes was respectively 10.21% and 20.42% by blood smear screening and 7.19%, 12.19% by PCR. The overall PCR based prevalence in the Sargodha and Multan districts was 19% and 15.25%, respectively. Absence of rural poultry, tick infestation, and a history of tick-borne diseases had significant effect in cattle. Tick infestation and age were the main statistically significant disease determinants in buffaloes. The evolutionary analysis of the cytochrome b gene showed that the Pakistani isolate infecting buffalo was related to those from Iran, India, Egypt, and Sudan. The isolate from cattle was genetically close to those from Pakistan, India, Iran, Iraq, and Turkey.

Conclusion

It can be concluded that biotic and abiotic factors contribute to disease occurrence. The current study will help to devise control strategies to prevent substantial economic losses.

Evolutionary analysis of Babesia vulpes and Babesia microti-like parasites

Background

The Babesia microti-like parasite is an emerging tick-borne piroplasm that has been detected in a range of hosts worldwide. Babesia vulpes, which is found in dogs and foxes, has been reclassified from B. microti-like parasites. The relationships among these B. microti-like parasites and B. vulpes with respect to host range and geographical origin have not been elucidated.

Methods

Blood samples were collected from 27 raccoon dogs in South Korea and used to screen for B. microti-like parasites based on a PCR assay targeting the 18S rRNA gene of Babesia. For comparative purposes, in addition to 18S rRNA sequences from nine raccoon dogs, we also analyzed 18S rRNA sequences from B. microti-like parasites infecting hosts in different geographical regions worldwide obtained from the GenBank database, giving 123 sequences in total. The genetic variation and evolutionary relationships among these sequences were examined based on analyses using DnaSP, MEGA, Arlequine, and BEAST software.

Results

Babesia microti-like parasites were identified in nine raccoon dogs and found to be related to B. vulpes obtained from Spanish dogs. Among the 123 sequences from 14 countries and various hosts, we identified 43 haplotypes with high genetic variance. Based on the genetic variance and phylogenetic analyses, we established that the B. microti-like parasites isolated in different geographical regions and from hosts belonging to five orders showed higher among-population variation than within-population variation. Babesia vulpes parasites infecting carnivore hosts, including raccoon dogs, foxes, skunks and dogs, appear to be genetically distinct from B. microti-like parasites infecting hosts belonging to the other orders.

Conclusions

Our study demonstrated the genetic variation and evolutionary relationships among 18S rRNA sequences obtained from blood samples collected from various hosts and different geographical regions. Babesia vulpes was identified from raccoon dogs in South Korea. In addition, higher genetic variations were observed among populations of different hosts and geographical origins and, in particular, low connectivity was observed among host populations in the order Carnivora and those in other orders. These results suggest the B. vulpes, a piroplasmid species pathogenic in domestic dogs and wild canines, is genetically and evolutionarily different from B. microti-like parasites.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05528-9.

Molecular evidence, risk factors analysis, and hematological alterations associated with Theileria spp. spillover in captive wild mouflon sheep in Punjab, Pakistan

Background

Landscape anthropization and interaction between domestic and wild animals are the major contributing factors involved in the emergence of new pathogens in wild animals. Theileriosis is an emerging issue of wild ungulates, especially in the tropical and subtropical areas of the globe.

Aims

The current study investigated the mouflon sheep for Theileria infection using molecular methods and hematological analysis.

Methods

This study was conducted on a total of 103 captive wild mouflon sheep present in eight different recreational zoos, and wildlife parks in Punjab, Pakistan to investigate the genotypic prevalence of Theileria spp. by targeting 18S rRNA and molecular evidence for Theileria spillover between domestic and wild mouflon sheep by phylogenetic analysis. The association of assumed risk factors and the effect of Theileria spp. on various hematological parameters were also assessed.

Results

The results depicted that Theileria spp. was prevalent in 8 (7.77%, CI 95%: 3.99-14.59%), and 11 (10.68%, CI 95%: 06.07-18.12%) animals based on microscopy, and PCR, respectively. The phylogenetic analysis of the 18S rRNA gene of Theileria spp. from mouflon revealed a close resemblance with T. annulata from domestic animals. The risk factor analysis revealed that tick infestation, enclosure hygiene, previous tick infestation history, and the presence of wooden logs in the enclosure were significantly (P<0.05) associated with the occurrence of Theileria spp. infection in the captive mouflon sheep of Pakistan. Furthermore, a significant reduction in blood parameters like PCV, RBCs count, Hb, and platelets was observed in Theileria-positive animals.

Conclusion

This study is the first evidence at the molecular level to characterize the spillover of Theileria spp. between the captive wild mouflon sheep and domestic animals of Pakistan, and it will be useful in developing control strategies for emerging theileriosis in captive wild animals.