Diagnostic approaches for tick-borne haemoparasitic diseases in livestock

Development and Evaluation of a Semi-Nested PCR Method Based on the 18S ribosomal RNA Gene for the Detection of Babesia aktasi Infections in Goats

We developed and evaluated a semi-nested PCR assay for the detection of Babesia aktasi infection in goats based on the sequence of the B. aktasi 18S ribosomal RNA gene. Following in silico screening, the specificity of the primers was assessed using reference DNA samples, including B. ovis, B. motasi, B. crassa, B. venatorum, B. divergens, B. capreoli, Theileria ovis, and T. annulata. To determine the sensitivity of the method, blood infected with 2% parasitemia of B. aktasi was diluted to 10-fold serial dilutions. The method specifically amplified a 438 bp fragment of B. aktasi DNA, but did not demonstrate cross-amplification with the other hemoparasites tested. The sensitivity assay indicated that this PCR method was able to detect infection at a dilution of 10-8 of 2% parasitemia (0.074 parasites/200 µL). Ninety-seven blood samples collected from goats were used to analyze for B. aktasi, and the infection was detected in 18.5% of the goats. Additionally, the method was also applied to 44 field DNA samples that were detected to be positive for B. aktasi by reverse line blotting (RLB), and showed 84.1% agreement. The findings revealed that newly developed semi-nested PCR can detect B. aktasi infections in goats with high sensitivity and specificity.

Genetic diversity of tick-borne zoonotic pathogens in ixodid ticks collected from small ruminants in Northern Pakistan

Mapping tick distribution and pathogens in unexplored areas sheds light on their importance in zoonotic and veterinary contexts. In this study, we performed a comprehensive investigation of the genetic diversity of tick and tick-borne pathogens (TBPs) detection infesting/infecting small ruminants across northern Pakistan. We collected 1587 ixodid ticks from 600 goats and sheep, an overall tick infestation rate of 50.2 %. Notably, gender-based infestation rates were higher in female goats and sheep compared to their male counterparts. Age-wise analysis showed that the tick infestation rate was higher in older animals. This study identified 11 ixodid tick species within three genera: Hyalomma, Haemaphysalis, and Rhipicephalus, which were taxonomically classified using 16S rRNA and cytochrome oxidase I (cox1) molecular markers. Sequence analysis indicated that reported ticks are similar to ixodid species found across various Asian and African countries. Tick-borne pathogens were detected by amplifying 16S rRNA and citrate synthase (gltA) for bacterial pathogens and 18S rRNA for apicomplexan parasites. The present study reported a diverse array of TBPs in ticks from the study area, with Rickettsia massiliae (24.5 %) and Theleria ovis (16.4 %) as the most prevalent bacterial and apicomplexan pathogens. Phylogenetically, detected TBPs shared evolutionary relatedness with identical TBPs from old and new world countries. These findings highlight the presence of zoonotic TBPs in ixodid ticks from Pakistan. In addition, it also provides a foundation for future epidemiological research on ticks and TBPs, emphasizing their relevance in both zoonotic and veterinary contexts.

Microscopic and molecular detection of piroplasms among sheep in Upper Egypt

Introduction

Blood parasites pose a significant threat to livestock production in southern Egypt, yet there is a scarcity of information regarding their circulation and epidemiology in sheep in this region. This study aimed to investigate the seroprevalence of blood parasite infections in sheep in Assiut governorate, Upper Egypt.

Methods

A total of 400 blood samples were collected from sheep of varying ages and genders. The preliminary screening for the presence of piroplasms, mainly Babesia and Theileria spp., via microscopic examination, followed by investigation of the potential risk factors linked with the exposure to infection. Moreover, molecular identification of both parasites on some of positive samples was performed using PCR targeting Babesia 18S rRNA and Theileria annulata Tams1 gene.

Results

The microscopic examination revealed that among the examined sheep, there was an overall prevalence of blood parasites at 44% (176 out of 400), with Babesia spp. observed in 14% (56 out of 400) and Theileria spp. in 30% (120 out of 400). Furthermore, the infection rate was non-significantly higher in young animals (50%) compared to adults (38.5%) (P = 0.246). Male sheep exhibited a significantly higher vulnerability to both parasites' infection (63.3%) compared to females (35.7%) (P = 0.011). Interestingly, the prevalence of both blood parasites was significantly higher during the cold season (66.1%) compared to the hot season (15.9%) (P = < 0.001). The molecular analysis identified the presence of Babesia ovis and Theileria annulata among a subsample of the positive sheep's bloods films. The identified species were recorded in the GenBank™ databases and assigned specific accession numbers (OQ360720 and OQ360719 for B. ovis), and (OP991838 for T. annulata).

Conclusions

Taken together, this study confirms a high prevalence of piroplasmosis and offers epidemiological and molecular insights into blood parasites in sheep from Upper Egypt, highlighting the importance of detecting these parasites in various hosts and their competent vectors (ticks).

Metabarcoding using nanopore long-read sequencing for the unbiased characterization of apicomplexan haemoparasites

Apicomplexan haemoparasites generate significant morbidity and mortality in humans and other animals, particularly in many low-to-middle income countries. Malaria caused by Plasmodium remains responsible for some of the highest numbers of annual deaths of any human pathogen, whilst piroplasmids, such as Babesia and Theileria can have immense negative economic effects through livestock loss. Diagnosing haemoparasites via traditional methods like microscopy is challenging due to low-level and transient parasitaemia. PCR-based diagnostics overcome these limitations by being both highly sensitive and specific, but they may be unable to accurately detect coinfections or identify novel species. In contrast, next-generation sequencing (NGS)-based methods can characterize all pathogens from a group of interest concurrently, although, the short-read platforms previously used have been limited in the taxonomic resolution achievable. Here, we used Oxford Nanopore Technologies' (ONT) long-read MinION™ sequencer to conduct apicomplexan haemoparasite metabarcoding via sequencing the near full-length 18S ribosomal RNA gene, demonstrating its ability to detect Babesia, Hepatozoon, Neospora, Plasmodium, Theileria and Toxoplasma species. This method was tested on blood-extracted DNA from 100 dogs and the results benchmarked against qPCR and Illumina-based metabarcoding. For two common haemoparasites, nanopore sequencing performed as well as qPCR (kappa agreement statistics > 0.98), whilst also detecting one pathogen, Hepatozoon felis, missed by the other techniques. The long-reads obtained by nanopore sequencing provide an improved species-level taxonomic resolution whilst the method's broad applicability mean it can be used to explore apicomplexan communities from diverse mammalian hosts, on a portable sequencer that easily permits adaptation to field use.

Transmission Cycle of Tick-Borne Infections and Co-Infections, Animal Models and Diseases

Tick-borne pathogens such as species of Borrelia, Babesia, Anaplasma, Rickettsia, and Ehrlichia are widespread in the United States and Europe among wildlife, in passerines as well as in domestic and farm animals. Transmission of these pathogens occurs by infected ticks during their blood meal, carnivorism, and through animal bites in wildlife, whereas humans can become infected either by an infected tick bite, through blood transfusion and in some cases, congenitally. The reservoir hosts play an important role in maintaining pathogens in nature and facilitate transmission of individual pathogens or of multiple pathogens simultaneously to humans through ticks. Tick-borne co-infections were first reported in the 1980s in white-footed mice, the most prominent reservoir host for causative organisms in the United States, and they are becoming a major concern for public health now. Various animal infection models have been used extensively to better understand pathogenesis of tick-borne pathogens and to reveal the interaction among pathogens co-existing in the same host. In this review, we focus on the prevalence of these pathogens in different reservoir hosts, animal models used to investigate their pathogenesis and host responses they trigger to understand diseases in humans. We also documented the prevalence of these pathogens as correlating with the infected ticks’ surveillance studies. The association of tick-borne co-infections with other topics such as pathogens virulence factors, host immune responses as they relate to diseases severity, identification of vaccine candidates, and disease economic impact are also briefly addressed here.

Epidemiological study on Ixodid tick infestation and tick borne haemopathogens on cattle in Awi Zone, northwest Ethiopia

BACKGROUND

Tick and tick borne haemopathogens are the main challenge of livestock production and productivity in Ethiopia particular in northwest Ethiopia due to favourable climate condition.

OBJECTIVES

The objectives of this study was to determining the prevalence of Ixodid tick infestation and tick borne haemopathogens on cattle, identifying the existing Ixodid tick species, assessing seasonal variation and major risk factors associated with tick infestation and tick borne haemopathogens.

METHODS

A cross-sectional study was conducted from December 2020 to july 2021 on Ixodid tick infestation and tick borne haemopathogens on cattle in the northwest Ethiopia. A toatal of 384 cattle were used for this study. Tick species were identified using morphological identification keys under a stereomicroscope. Thin blood smear examination were conducted to assess tick borne haemopathogens.

RESULTS

The overall prevalence of Ixodid tick infestation and tick borne haemopathogens were 45% and 3%, respectively. Babesia bigemina was the only haemoparasite detected in the present survey. Potential risk factors were investigated for their association with tick infestation and B. bigemina using logistic regression and chi-square test, respectively. Accordingly, age, body condition, agroecological systems and season were significantly (p < 0.05) associated with tick infestation whereas season and body condition were significantly (p < 0.05) associated with B. bigemina infection. A total seven tick species were identified. Amblyomma varigatum (55%) and Boophilus decoloratus (15.7%) were the predominant Ixodid tick species encountered. A total of 128 blood samples were collected from Jawi district and examined using thin blood smear. Of them, 3% were infected by the B. bigemina CONCLUSIONS: Tick infestation in this study was high and seems to play vital role for the reduction of production, productivity and for the transmission B. bigemina. Therefore, sound and effective tick control and prevention strategies are needed to mitigate the risk factors for tick infestation and B. bigemina infection in Ethiopia.

Molecular epidemiology, phylogenetic analysis and risk assessment of Anaplasma marginale from naturally infected bovines of Punjab (India)

Anaplasmosis, an infectious vector borne rickettsial disease caused by different species of Anaplasma transmitted through mechanical and biological (tick) processes has a great concern to livestock industry due to its associated economic losses. The current cross sectional comprehensive epidemiological study was conducted from August 2020 to November 2021 on 391 (277 cattle and 114 buffaloes) bovines from different districts of five agro climatic zones of Punjab state. Classical microscopic examination of Romanowsky stained blood smears showed an occurrence of 13.00%, while DNA amplification targeting major surface protein (msp5) of Anaplasma marginale revealed the 382 bp amplicon in 32.48% samples. Zone based molecular prevalence of A. marginale was highest in the Undulating zone (41.93%) and least in the Sub-Mountain zone (18.84%). The prevalence in Central plain zone, Western plain zone, and Western zone were 40.15, 30.95 and 29.91%, respectively. An overall molecular prevalence of A. marginale was 34.52, 32.75 and 20.0% in young, adults and calves, respectively, the difference being non-significant. Anaplsma marginale was more prevalent in unorganized farms (38.22%; 60/157) than organized farms (28.63%; 66/234). Risk factors analysis revealed young, female cattle at unorganized farms were more prone to anaplasmosis. Out of 127 positive samples, four samples were customed to sequencing revealed 98-99% homology with published sequences for other available global isolates. Multi-single nucleotide polymorphisms (SNP) were observed in the sequence of two samples when aligned with the reference sequence from the NCBI database (CP023731).

Molecular survey for tick-borne pathogens and associated risk factors in sheep and goats in Kano Metropolis, Nigeria

Tick-borne pathogens (TBPs) pose an increased health and productivity risk to livestock in sub-Saharan Africa. Information regarding TBPs infecting small ruminants in Kano metropolis is scarce. Therefore, we investigated the molecular epidemiology of tick-borne pathogens of economic importance from sheep and goats in Kano, Nigeria using Polymerase chain reaction (PCR). A total of 346 blood DNA samples were collected from small ruminants and analyzed for TBPs using PCR and sequencing. Risk of infection was determined for age, sex, breed and animal species. Our results indicate the absence of piroplasmids (Babesia/Theileria) and Rickettsia spp. infections. The overall prevalence for Anaplasma spp. was 9.25% (32/346) with a higher prevalence in goats 13.59% (25/184) compared with sheep 4.32% (7/162). With respect to age of animals, goats >4 years had the highest prevalence of 32.45% (11/37) which differs significantly (P = 0.0059) compared with other age categories. Cross breed goats had a prevalence of 15.63% (5/32) compared with Kano brown breed 14.08 (20/142). Sex significant difference (P = 0.029) was observed in the goats with females having the highest prevalence 20.89% (14/67) compared with males 9.40% (11/117). Furthermore, with regards to sheep, no significant difference (P > 0.05) was observed with respect to age and breed. Finally, no significant difference (P > 0.05) was observed with the prevalence of Anaplasma spp. due to Body condition score (BCS) in both sheep and goats. Conclusively, the occurrence of TBPs in small ruminants is low. Continuous efforts in tick control must be sustained to ensure high productive yield and reduced disease burden associated with TBPs of sheep and goats in Kano metropolis.

Targeted mutagenesis in Anaplasma marginale to define virulence and vaccine development against bovine anaplasmosis

Tick-borne Anaplasma species are obligate, intracellular, bacterial pathogens that cause important diseases globally in people, agricultural animals, and dogs. Targeted mutagenesis methods are yet to be developed to define genes essential for these pathogens. In addition, vaccines conferring protection against diseases caused by Anaplasma species are not available. Here, we describe a targeted mutagenesis method for deletion of the phage head-to-tail connector protein (phtcp) gene in Anaplasma marginale. The mutant did not cause disease and exhibited attenuated growth in its natural host (cattle). We then assessed its ability to confer protection against wild-type A. marginale infection challenge. Additionally, we compared vaccine protection with the mutant to that of whole cell A. marginale inactivated antigens as a vaccine (WCAV) candidate. Upon infection challenge, non-vaccinated control cattle developed severe disease, with an average 57% drop in packed cell volume (PCV) between days 26-31 post infection, an 11% peak in erythrocytic infection, and apparent anisocytosis. Conversely, following challenge, all animals receiving the live mutant did not develop clinical signs or anemia, or erythrocyte infection. In contrast, the WCAV vaccinees developed similar disease as the non-vaccinees following A. marginale infection, though the peak erythrocyte infection reduced to 6% and the PCV dropped 43%. This is the first study describing targeted mutagenesis and its application in determining in vivo virulence and vaccine development for an Anaplasma species pathogen. This study will pave the way for similar research in related Anaplasma pathogens impacting multiple hosts.

Theileria orientalis outbreak in an organized cattle breeding farm

Theileriosis is an important tick borne disease of cattle caused by a haemoprotozoan of genus Theileria. Clinical bovine theileriosis is mainly caused by T. annulata or T. parva but the clinical disease due to T. orientalis is rare. T. orientalis mainly infect RBCs and causes "Oriental theileriosis" or Theileria-associated bovine anaemia in cattle and other livestock species. Two genotypes of T. orientalis (Chitose and Ikeda) are reported to cause severe disease in some countries. In this report, a spontaneous outbreak of Oriental theileriosis was studied in an organized Holstein-Friesian cattle breeding farm situated in the south-eastern Himalayan ranges of Himachal Pradesh State of India. Animal blood and tick samples were tested using cytological and PCR techniques. The disease episode occurred in a protracted manner spanning over 10 to 12 months and association of T. orientalis was confirmed in 93.3% of the blood and 21.7% of Rhipicephalus microplus (tick) samples. No other tick borne pathogen was detected except Anaplasma marginale in two blood samples. Haematological profiling of infected cattle showed characteristic indicators of anaemia like haemoblobin, RBC count, haematocrit value and mean corpuscular volume at either lower than normal or near the lower normal range. The prevailing persistent anaemic changes led to more severe clinical manifestations like abortion and joint inflammation. The detected T. orientalis strains and ticks species were further confirmed by nucleotide sequence analysis of 18S rRNA and 16S rRNA genes. Phylogenetically, T. orientalis strains showed clustering with other reported strains of T. orientalis from the surrounding regions. This first report of clinical Oriental theileriosis from India emphasises the importance of T. orientalis as an emerging tick borne pathogen and role of widely prevalent ticks species in disease transmission and their impact on livestock production.

Evaluation of sporozoite and macroschizont antigen (Spm2) of Theileria annulata for its diagnostic potential

Theileria are tick-borne apicomplexan parasites, which mainly infect ruminants in tropical and subtropical regions of the world. The present study was directed to investigate the serological methods for the diagnosis of theileriosis in crossbred cattle. Blood samples (n = 176) were collected from the regional cattle populations of Bihar state situated at the Gangetic plains of India. Microscopic examination of blood smears from the cattle revealed the presence of tick-borne infectious organisms (Theileria and Anaplasma) in the region. PCR-based detection of Tams1 (Theileria annulata merozoite surface antigen) gene and the sequencing of 18S rRNA amplicon from the blood samples confirmed T. annulata as the primary causative agent of theileriosis in cattle of the Bihar region. Similarly, the amplification of the msp5 gene confirmed Anaplasma marginale infection. For the large-scale epidemiological investigation, sporozoite and macroschizont (spm2) partial gene from T. annulata was cloned in pET-28a (+) vector and overexpressed in E. coli BL21 cells. Overexpressed recombinant-Spm2 (43 kDa) was purified by Ni-NTA affinity chromatography and was used for immunodetection of theileriosis in cattle serum samples. Sequence analysis of the cloned partial spm2 gene in this study showed multiple SNPs (single nucleotide polymorphisms) in T. annulata. Recombinant-Spm2 antigen was explicitly recognised by the immunoglobulins (IgG) of the cattle naturally infected with Theileria. Further, an indirect enzyme-linked immunosorbent assay (ELISA) was developed using partial r-Spm2 antigen that exhibited high sensitivity (100 %) and specificity (90.9 %). Thus, this study suggests that partial r-Spm2 can be used as a diagnostic antigen for seroepidemiological studies of T. annulata infection in crossbred cattle.

Prevalence of ticks (Acari: Ixodidae) and Theileria lestoquardi in sheep at El Huda and El Nuhud animals production research stations, Sudan

A cross-sectional study was performed 200 blood samples and 314 tick samples in El Huda and El Nuhud animals production research stations, Sudan, in May (summer) and December (winter) in 2016, to determine the prevalence of Theileria lestoquardi in sheep and the potential risk factors associated with the infection. A total of 200 blood samples and 314 tick samples were collected from El Huda (n = 103 blood, 97 tick) and El Nuhud (n = 97 blood, 217 tick) stations. Data on the risk factors, such as age, sex, ecotype of sheep, body condition score and seasons were recorded. The overall prevalence of Theileria lestoquardi was 13% (26/200) using PCR. A significant variation in the prevalence of Theileria lestoquardi was observed between the stations and the ecotype of sheep (p ≤ 0.05), whereas the highest prevalence was recorded in El-Huda station (19.4%) as well as in Shugor (22.8%). Other risk factors, like age, sex, body condition, and seasons were not found to be significantly associated with infection. However, the highest prevalence rate was recorded in old animals (21.6%) than the other, in males (17.9%) than females (12.2%), in animals with poor body condition (26.1%) than the other, and in winter (16%) than summer (10%). Four tick species i.e. Rhipicephalus evertsi evertsi (63.1%), Hyalomma anatolicum (13.8%), Hyalomma dromedarii (8.8%), and Hyalomma impeltatum (14.3%) were recorded in El Nuhud station. While in El Huda station, only Rhipicephalus evertsi evertsi (79.4%), Hyalomma anatolicum (20.6%) were recorded. This study revealed that 13% of sheep were suffering from Theileria lestoquardi which is a considerable number at the stations. Therefore, further epidemiological investigations on disease throughout the year are required in order to set a well-coordinated control program.

An Assessment of the Molecular Diversity of Ticks and Tick-Borne Microorganisms of Small Ruminants in Pakistan

This study investigated ticks and tick-borne microorganisms of small ruminants from five districts of the Federally Administered Tribal Area (FATA) of Pakistan. Morphological (n = 104) and molecular (n = 54) characterization of the ticks revealed the presence of six ixodid ticks: Rhipicephalus (Rh.) haemaphysaloides, Rh. microplus, Rh. turanicus, Haemaphysalis (Hs.) punctata, Hs. sulcata and Hyalomma anatolicum. Phylogenetic analyses of nucleotide sequence data for two mitochondrial (16S and cytochrome c oxidase 1) and one nuclear (second internal transcribed spacer) DNA regions provided strong support for the grouping of the six tick species identified in this study. Microfluidic real-time PCR, employing multiple pre-validated nuclear and mitochondrial genetic markers, detected 11 potential pathogens and endosymbionts in 72.2% of the ticks (n = 54) tested. Rickettsia (R.) massiliae was the most common pathogen found (42.6% of ticks) followed by Theileria spp. (33.3%), Anaplasma (A.) ovis and R. slovaca (25.9% each). Anaplasma centrale, A. marginale, Ehrlichia spp., R. aeschlimannii, R. conorii and endosymbionts (Francisella- and Coxiella-like) were detected at much lower rates (1.9–22.2%) in ticks. Ticks from goats (83.9%) carried significantly higher microorganisms than those from sheep (56.5%). This study demonstrates that ticks of small ruminants from the FATA are carrying multiple microorganisms of veterinary and medical health significance and provides the basis for future investigations of ticks and tick-borne diseases of animals and humans in this and neighboring regions.

Bovine ticks harbour a diverse array of microorganisms in Pakistan

BACKGROUND

Ticks and tick-borne pathogens (TTBP) are a major constraint to livestock production in Pakistan; despite a high prevalence of TTBPs, knowledge on the capacity of Pakistani ticks to carry pathogens and endosymbionts is limited. Furthermore, mixed infections with multiple microorganisms further complicate and limit the detection potential of traditional diagnostic methods. The present study investigated the tick-borne microorganisms in bovine ticks in Pakistan, employing a high-throughput microfluidic real-time PCR based technique.

METHODS

Ticks were collected from clinically healthy cattle (n = 116) and water buffaloes (n = 88) from 30 villages across six districts located in five agro-ecological zones (AEZs) of Pakistan from September to November 2017. The microfluidic real-time PCR was used to test the genomic DNA of individual ticks for the presence of 27 bacterial and eight parasitic microorganisms. Phylogenetic methods were used to assess the genetic relationship of DNA sequences determined herein.

RESULTS

PCR detected DNA of at least one microorganism in each of 221 ticks tested (94.4%, 221/234). DNA-based detection inferred that single pathogens/endosymbionts were the most common (43.4%, 96/221) followed by double (38.9%, 86/221), triple (14.5%, 32/221), quadruple (2.3%, 5/221) and quintuple (0.9%, 2/221) mixed infections. Piroplasms (Babesia/Theileria spp.) were the most prevalent (31.6%, 74/234), followed by Ehrlichia spp. (20%, 47/234) and Anaplasma marginale (7.7%, 18/234). Anaplasma phagocytophilum, A. ovis, A. centrale, Babesia ovis, Borrelia spp., Rickettsia spp., R. massiliae, Bartonella spp. and Hepatozoon spp. were also detected. Endosymbionts such as Francisella-like (91.5%, 214/234) and Coxiella-like (1.3%, 3/234) organisms were also detected in ticks. The highest diversity of microorganisms was detected in Hyalomma anatolicum ticks (test-positive for 14/14 microorganisms), followed by Rhipicephalus microplus (4/14), Hy. hussaini (3/14) and Rh. annulatus (2/14). Ticks collected from cattle carried significantly more frequently piroplasms (41.2%, 54/131; P < 0.05) than those from buffaloes (19.4%, 20/103). However, the overall prevalence of microorganisms did not vary significantly among ticks from the two host species as well as across different AEZs.

CONCLUSIONS

To our knowledge, this is the first study to investigate a wide range of tick-borne microorganisms in bovine ticks using a high-throughput diagnostic method from different AEZs in Pakistan. These findings will aid in establishing the distribution patterns and the control of tick-borne pathogens of bovines in Pakistan.

Molecular identification and prevalence of tick-borne pathogens in zebu and taurine cattle in North Cameroon

Background

Public interest for tick-borne pathogens in cattle livestock is rising due to their veterinary and zoonotic importance. Consequently, correct identification of these potential pathogens is crucial to estimate the level of exposition, the risk and the detrimental impact on livestock and the human population.

Results

Conventional PCR with generic primers was used to identify groups of tick-borne pathogens in cattle breeds from northern Cameroon. The overall prevalence in 1260 blood samples was 89.1%, with 993 (78.8%) positive for Theileria/Babesia spp., 959 (76.1%) for Anaplasma/Ehrlichia spp., 225 (17.9%) for Borrelia spp., and 180 (14.3%) for Rickettsia spp. Sanger sequencing of a subset of positively-tested samples revealed the presence of Theileria mutans (92.2%, 130/141), T. velifera (16.3%, 23/141), Anaplasma centrale (10.9%, 15/137), A. marginale (30.7%, 42/137), A. platys (51.1%, 70/137), Anaplasma sp. ‘Hadesa’ (10.9%, 15/137), Ehrlichia ruminantium (0.7%, 1/137), E. canis (0.7%, 1/137), Borrelia theileri (91.3%, 42/46), Rickettsia africae (59.4%, 19/32) and R. felis (12.5%, 4/32). A high level of both intra- and inter-generic co-infections (76.0%) was observed. To the best of our knowledge, B. theileri, T. mutans, T. velifera, A. platys, Anaplasma sp. ‘Hadesa’, R. felis and E. canis are reported for the first time in cattle from Cameroon, and for R. felis it is the first discovery in the cattle host. Babesia spp. were not detected by sequencing. The highest number of still identifiable species co-infections was up to four pathogens per genus group. Multifactorial analyses revealed a significant association of infection with Borrelia theileri and anemia. Whereas animals of older age had a higher risk of infection, the Gudali cattle had a lower risk compared to the other local breeds.

Conclusion

Co-infections of tick-borne pathogens with an overall high prevalence were found in all five study sites, and were more likely to occur than single infections. Fulani, Namchi and Kapsiki were the most infected breed in general; however, with regions as significant risk factor. A better-adapted approach for tick-borne pathogen identification in co-infected samples is a requirement for epidemiological investigations and tailored control measures.

Prevalence of haemoprotozoan diseases in cattle of Cauvery delta region of Tamil Nadu

A study was carried out to determine the prevalence of haemoparasites in cattle in Cauvery delta region over a period of one year. A total of 228 giemsa stained blood smears were screened for the presence of haemoprotozoa, out of which 34 animals were found to be positive. An overall prevalence of haemoparasites in the sampled cattle were 14.9%, among this Anaplasma sp (8.3%), Babesia sp (3.95%), Theileria sp (2.19%) and Trypanosoma sp (0.44%) as single or mixed blood parasitic infections. In this study Anaplasmosis (14%) was highly prevalent during the winter season and Babesiosis (13.73%) was highly prevalent during summer months followed by Anaplasmosis (9.8%) and Theileriosis (7.8%), the lowest prevalence of Trypanosomiasis was observed during the rainy season. The seasonal variation in prevalence of haemoprotozoan disease might be due to influence of climatic factors on density of vector population in that geographical area. Haemogram revealed decreased level of haemoglobulin, packed cell volume and total erythrocyte count. The serum biochemistry revealed elevated level of liver enzyme Asparate transaminase enzyme. All haemoparasitaemic animals were treated with specific drugs and recovered successfully.

Development of multiplex PCR assay for concurrent detection of tick borne haemoparasitic infections in bovines

This study describes development and evaluation of a multiplex PCR assay for simultaneous detection of Theileria annulata, Babesia bigemina and Anaplasma marginale infections in bovines. The assay was developed using parasites specific genomic DNA and three sets of PCR primers targeting the Tams1, 18S rRNA and 16S rRNA genes of T. annulata, B. bigemina and A. marginale, respectively. Blood samples collected from a total of 461 bovines, suspected for haemoparasitic infections, were examined microscopically to record the status of infection and simultaneously, genomic DNA extracted from these blood samples were utilized for the optimization and validation of multiplex PCR assay. Microscopic examination of blood samples revealed presence of single and multiple species of haemoparasites in 25.8% and 2.4% samples, respectively. Results of multiplex PCR revealed the presence of single haemoparasitic species infection in 159 cases (34.5%), whereas mixed infection was recorded in 82 (17.8%) samples. Occurrence of individual species infection detected by mPCR in the study was 26.03% (120/461) for T. annulata, 3.25% (15/461) for B. bigemina and 5.20% (24/461) for A. marginale. The detection limit of multiplex PCR assay was at the template dilutions of 10-6, 10-6 and 10-4, which corresponded to 0.1 pg, 0.1 pg and 10.0 pg of DNA for T. annulata, A. marginale, and B. bigemina, respectively. Based on the high diagnostic sensitivity and throughput, multiplex PCR assay developed in the present study could be exploited as a tool to conduct large-scale epidemiological survey for tick-borne haemoparasitic infection of bovines.

Molecular, serological and parasitological survey of Theileria annulata in North Kordofan State, Sudan

This survey was conducted to detect Theileria annulata infection in indigenous (Zebu) and cross (indigenous × Friesian) cattle (n 604) of different sex & age groups, and to investigate prevalence of ticks infesting cattle in North Kordofan State, Sudan. Ticks, blood smears, serum samples and blood spots on filter paper were collected from four municipalities at four monthly intervals during the period from August 2008 to July 2009. Out of 604 blood smears, 69 (11.4%, 95% CI: 16.9-5.9) were positive for Theileria piroplasms; whereas, out of 240 serum samples, 164 (68.3%, 95% CI: 89.3-47.3) were positive for antibodies against T. annulata using IFA test. Using PCR, out of 100 blood spots on filter paper, 8 (8%, 95% CI: 9.6-6.4) revealed T. annulata DNA. The highest prevalence of Theileria spp. piroplasms and T. annulata antibodies was recorded in August (15.9 ± 4.6) followed by February (13.3 ± 3.8) and the lowest was in May (3.9 ± 1.0). Among cattle breeds, the highest prevalence of piroplasms (11.9 ± 5.0) and T. annulata antibodies (68.9 ± 10) was among zebu cattle. PCR assays revealed the highest prevalence rate of T. annulata DNA in February (12.5 ± 1.4) followed by August (6.1 ± 0.7) and the lowest was in May (5.7 ± 0.7). According to cattle breeds, T. annulata DNA was detected in cross-bred cattle (3.3 ± 0.4) more than zebu cattle (10 ± 1.6). Seven tick species belonging to four genera and were identified, Amblyomma lepidum, Hyalomma dromedarii, H. impeltatum, H. rufipes, Rhipicephalus evertsi evertsi, Rhipicephalus decoloratus, R. annulatus. The most abundant tick species was H. rufipes followed by H. impeltatum, R. e. evertsi, H. dromedarii, R. decoloratus, A. lepidum and R. annulatus. Theileria annulata has been detected for the first time in North Kordofan State, though at a low prevalence rate. This finding is an alarming situation since tropical theileriosis is an emerging disease and it is widely believed that this economically important tick-borne parasite does not exist in this state. The possible alternative vector(s) of T. annulata in the absence of the known vector H. anatolicum is discussed.

Acaricidal potency of polyherbal spray against Rhipicephalus microplus and Hyalomma anatolicum infestation in cattle

Acaricidal potential of polyherbal spray (Andropogon citrates, Cymbopogon citratus, Ocimum sanctum, Pinus longifoia, Calotropis procera, Datura stramonium, Aegle marmelos, Ricinus communis, Azadirachta indica, Allium sativum, Carica papaya, Annona squamosa and Pongamia glabra) was assessed against tick infestation in cattle on the basis of measurement of tick count, complete blood count and plasma glucose, total protein, albumin and globulin before treatment and 21 days after treatment. Single application of polyherbal spray over body of 20 randomly selected tick infested cattle revealed significant reduction in mean tick count starting from 3 days post treatment till 21 days post treatment. Highly significant (P < 0.01) increase in total erythrocyte count and packed cell volume was observed in treated cows 21 days after application of spray compared to pre-treatment values indicating the reduction in blood loss due to heavy tick infestation before treatment. Plasma biochemical parameters revealed no significant changes in pre-treatment and post treatment values. The results of present study imply the clinical and haematological improvement in tick infested cattle treated with polyherbal spray and it could be potential product for use in livestock as acaricide.

PCR diagnosis of tick-borne pathogens in Maharashtra state, India indicates fitness cost associated with carrier infections is greater for crossbreed than native cattle breeds

Tick-borne pathogens (TBP) are responsible for significant economic losses to cattle production, globally. This is particularly true in countries like India where TBP constrain rearing of high yielding Bos taurus, as they show susceptibility to acute tick borne disease (TBD), most notably tropical theileriosis caused by Theileria annulata. This has led to a programme of cross breeding Bos taurus (Holstein-Friesian or Jersey) with native Bos indicus (numerous) breeds to generate cattle that are more resistant to disease. However, the cost to fitness of subclinical carrier infection in crossbreeds relative to native breeds is unknown, but could represent a significant hidden economic cost. In this study, a total of 1052 bovine blood samples, together with associated data on host type, sex and body score, were collected from apparently healthy animals in four different agro-climatic zones of Maharashtra state. Samples were screened by PCR for detection of five major TBPs: T. annulata, T. orientalis, B. bigemina, B. bovis and Anaplasma spp.. The results demonstrated that single and co-infection with TBP are common, and although differences in pathogen spp. prevalence across the climatic zones were detected, simplistic regression models predicted that host type, sex and location are all likely to impact on prevalence of TBP. In order to remove issues with autocorrelation between variables, a subset of the dataset was modelled to assess any impact of TBP infection on body score of crossbreed versus native breed cattle (breed type). The model showed significant association between infection with TBP (particularly apicomplexan parasites) and poorer body condition for crossbreed animals. These findings indicate potential cost of TBP carrier infection on crossbreed productivity. Thus, there is a case for development of strategies for targeted breeding to combine productivity traits with disease resistance, or to prevent transmission of TBP in India for economic benefit.