Molecular characterization of South Indian field isolates of bovine Babesia spp. and Anaplasma spp

Cladistics and population structure analysis of Anaplasma marginale (Rickettsiales: Anaplasmataceae) in Haryana, India based on genes encoding the major surface proteins

Anaplasma marginale, a tick-borne obligate intracellular rickettsia is incriminated to cause heavy economic losses throughout the tropical and subtropical regions, including India. However, studies highlighting the phylogeography and demographic dynamics of A. marginale are very scant from India. Thus, the present study assessed the cladistics and population structure of Anaplasma marginale based on the genes encoding the major surface proteins (MSP) 4 and 5. The cladistics based on phylogenetic tree including the sequences generated herein with the GenBank archived sequences of A. marginale was performed. The relationship between A. marginale haplotypes based on both the genetic markers was estimated by performing median joining (MJ) haplotype network analysis. Demographic dynamics involving population diversity indices and neutrality indices was also performed. The cladistics and MJ haplotype network analysis corresponding to both the markers demonstrated the presence of three distinct clades (1-3) of A. marginale. Population structure analysis revealed low nucleotide (0.00236 ± 0.00064 and 0.00955 ± 0.00101) and haplotype (0.321 ± 0.073 and 0.493 ± 0.083) diversities for the MSP4 and MSP5 genes, respectively. High genetic structuring and low gene flow [Nm values ranging between 0.044481 and 0.208337 for the MSP4 gene and 0.032735 (clades 1 and 2) for the MSP5 gene] was also recorded among the different clades of A. marginale, based on both genetic markers. The present study highlighted the presence of different clades of A. marginale distributed worldwide. The isolates circulating in north India belonged to the dominant clade prevalent throughout the globe.

Multiplex PCR for detection of Anaplasma marginale, A. bovis and A. platys in cattle

Anaplasma genus has been classified under the family Anaplasmataceae of order Rickettsiales, which contains the spp. Anaplasma marginale, Anaplasma bovis, Anaplasma centrale, Anaplasma platys and Anaplasma phagocytophilum is accountable for a broad range of diseases in both man and animal medicine around the globe. A multiplex PCR procedure was designed to identify A. marginale, A. bovis, and A. platys simultaneously by employing species-specific primers targeting the msp4 (Anaplasma marginale), 16S rRNA (Anaplasma bovis), and groEL (Anaplasma platys) genes. The sensitivity of the assay was ascertained by tenfold dilutions of DNA obtained from cattle blood infected with A. marginale, A. bovis, and A. platys was used to evaluate the test sensitivity. A total of 31 Anaplasma genus positive samples were subjected to mPCR by using species specific primers for simultaneous detection of all the three species. All the 31 samples showed amplification of 753 bp fragment specific for A. marginale and 61.29% of the samples showed amplification of 547 bp fragment specific for A. bovis. The 470 bp DNA fragment specific for A. platys was found in 96.7% of samples. The lower limit of detection of the method for A. platys, A. marginale and A. bovis was found to be 4.4, 0.44 and 0.044 ng/µl, respectively.

Molecular Detection and Identification of Piroplasm in Cattle from Kathmandu Valley, Nepal

BACKGROUND

Tick-borne protozoan parasites (TBPPs) cause significant problems for domestic animals' health in Nepal. TBPPs are routinely diagnosed by labor-intensive blood smear microscopy. In Nepal, there are some reports of Babesia and Theileria in cattle, although species identification is rarely performed. Therefore, we performed conventional nested PCR (nPCR) followed by sequence analysis to identify TBPP species infecting cattle in Nepal.

METHODS

One hundred and six blood samples were collected from cattle in the Kathmandu Valley. Thin blood smears were prepared for microscopic examination. Parasite DNA was extracted from the blood, and nPCR and sequencing were performed to identify the TBPPs present.

RESULTS

Among the 106 samples, 45 (42.5%) were positive for piroplasm (Babesia spp. and Theileria spp.) via microscope observation and 56 (52.8%) samples were positive via nPCR. The obtained PCR products were used for direct sequencing, and we identified the species as B. bigemina, B. bovis, T. annulate and T. orientalis. Phylogenetic analyses showed that the B. bovis, B. bigemina and T. orientalis sequences from this study belonged to each species clade. On the other hand, T. annulate was divided into two clades in the analysis, and our T. annulate sequences were also divided in these two clades. The piroplasm-positive cattle showed lower hemoglobin and red blood cells than healthy cattle.

CONCLUSIONS

To the best of our knowledge, this study is the first to apply molecular detection and species determination of TBPPs in cattle in Nepal. The results of this study may be used as a starting point for the development of successful TBPP surveillance and prevention programs in Nepal.

Phylogenetic analyses of the mitochondrial, plastid, and nuclear genes of Babesia sp. Mymensingh and its naming as Babesia naoakii n. sp

BACKGROUND

The recently discovered Babesia sp. Mymensingh, which causes clinical bovine babesiosis, has a wide geographical distribution. We investigated the phylogenetic position of Babesia sp. Mymensingh using its mitochondrial, plastid, and nuclear genes. Based on morphological and molecular data, Babesia sp. Mymensingh is a unique species and we named it as Babesia naoakii n. sp.

METHODS

A blood DNA sample from a Babesia sp. Mymensingh-infected cow was subjected to genome sequencing to obtain the sequences of mitochondrial, plastid, and nuclear genes. Six phylogenetic trees were then constructed with (1) concatenated amino acid sequences of cytochrome oxidase subunit I, cytochrome oxidase subunit III, and cytochrome b genes of the mitochondrial genome; (2) 16S rRNA of the plastid genome; (3) nucleotide sequences of the elongation factor Tu gene of the plastid genome; (4) ITS1-5.8S rRNA-ITS2; (5) concatenated nucleotide sequences of 89 nuclear genes; and (6) concatenated amino acid sequences translated from the 89 nuclear genes.

RESULTS

In all six phylogenetic trees, B. naoakii n. sp. formed a sister clade to the common ancestor of Babesia bigemina and B. ovata. The concatenated nuclear genes of B. naoakii n. sp. and their translated amino acid sequences shared lower identity scores with the sequences from B. bigemina (82.7% and 84.7%, respectively) and B. ovata (83.5% and 85.5%, respectively) compared with the identity scores shared between the B. bigemina and B. ovata sequences (86.3% and 87.9%, respectively).

CONCLUSIONS

Our study showed that B. naoakii n. sp. occupies a unique phylogenetic position distinct from existing Babesia species. Our findings, together with morphological differences, identify B. naoakii n. sp. as a distinct parasite species.

Bovine babesiosis in India: Estimation of prevalence by systematic review and meta analysis

Bovine babesiosis is a serious threat to the livestock sector especially in tropical countries like India. Understanding the epidemiology of the disease in the country is essentially important in strategizing the available methods to effectively control the disease. Keeping this as the background, the present study was undertaken to estimate the pooled prevalence of bovine babesiosis in India. The relevant literature pertaining to bovine babesiosis was identified and a total of 49 studies published between 1983 and 2018 were included in the final systematic review and meta-analysis. Meta-analysis was conducted using meta-package of R software and prevalence estimates were calculated. Bovine babesiosis was reported from 21 states of India with pooled prevalence estimate of 6% (95% CI = 4%-9%) using random effect model. Zone wise analysis revealed highest pooled prevalence in the west zone and north zone (8%) followed by east zone (7%), central zone (6%), south zone (4%) and northeast zone (4%). The results of meta-analysis indicated high variability between studies. In addition, the pooled seroprevalence was high (29%) compared to prevalence of active infection (5%) of bovine babesiosis in India. Further, the pooled prevalence estimate of B. bigemina infection in India was more (7%) compared to B. bovis infection (1%). The estimation of prevalence of active infection and seroprevalence separately will helps to understand the actual disease prevalence in the country. The study indicated the wide prevalence of bovine babesiosis in India which urges for immediate mitigation strategies.

First molecular detection of Anaplasma species in cattle from Kyrgyzstan; molecular identification of human pathogenic novel genotype Anaplasma capra and Anaplasma phagocytophilum related strain

Anaplasmosis is a rickettsial infection with significant effects on human and animal health, and the discovery of new species or genotypes with zoonotic potential in recent years has increased this importance. The aim of this study was to provide the first assessment of the molecular etiology and prevalence of bovine anaplasmosis in Kyrgyzstan (specifically in the Chuy, Talas, Djalal-Abad, Naryn, and Issyk-Kul regions). The prevalence of bovine anaplasmosis was determined as 1.7% (6/358). PCR and partial DNA sequencing results of the 16S ribosomal RNA (rRNA) gene revealed that Anaplasma centrale, A. phagocytophilum like-1, and the human pathogenic novel genotype A. capra are circulating in cattle herds in Kyrgyzstan. Six DNA nucleotide sequences obtained in this study were deposited in GenBank under the following accession numbers: A. centrale (MW672117, MW672118, MW672119, MW672120), A. phagocytophilum (MW672121), and A. capra (MW672115).

South Indian zebu dwarf cattle show higher natural resistance to tick infestation compared to crossbreds: preliminary observations

The present study aimed to evaluate the influence of various factors on the host resistance of cattle against tick infestation in Kerala State, South India. The number of naturally infested semi-engorged female ticks present on the cattle was counted on a sample cattle population across the four regions of Kerala. Then, the animals were grouped based on the tick count. The chi-square test and Fisher exact test were used to identify the effects of genetic and non-genetic factors on tick burden in cattle. It was found that the Holstein Friesian crossbred and Jersey crossbred cattle had a significantly higher level of tick infestation than the indigenous Vechur breed (Bos indicus). No tick infestation was observed in indigenous Kasaragod Dwarf cattle (B. indicus). Tick infestation was more in heifers and dry animals than lactating animals. However, the sex of the animal and the stage of lactation did not influence the tick load. Tick infestation was also influenced by parity, grazing, and region.

Epidemiology, haematology and molecular characterization of haemoprotozoon and rickettsial organisms causing infections in cattle of Jammu region, North India

BACKGROUND

The present study was aimed at establishing the prevalence, epidemiology and molecular characterization of major haemoprotozoons (Babesia and Theileria) and rickettsia (Anaplasma) of cattle in Jammu region (North India) using microscopy and Polymerase Chain Reaction (PCR). Hematology, microscopy and PCR based prevalence studies were undertaken with 278 whole blood samples from cattle. Molecular prevalence studies were followed by genetic characterization of the isolates of Babesia, Anaplasma and Theileria spp. based on 18S rRNA, 16S rRNA and Tams1 gene, respectively. The data related to metrology and epidemiological variables like temperature, rainfall, season, age and type of livestock rearing was analyzed and correlated with occurrence of disease by statistical methods.

RESULTS

The prevalence based on microscopy was 12.9% (36/278) whereas PCR recorded 30.22% (84/278) animals positive for haemoparasitic infections. All the samples found positive by microscopy were also recorded positive by PCR. Thus the study revealed prevalence of Babesia bigemina, Anaplasma marginale and Theileria annulata to be 9.7, 16.5 and 0.7% respectively. The metrological and epidemiological variables made inroads for the propagation of vector ticks and occurrence of infection. Haematological alterations predominantly related to decrease in haemoglobin, red blood cell count and packed cell volume were evident in diseased animals and collaterally affected the productivity. Further the genetic characterization of Babesia bigemina. (MN566925.1, MN567603, MN566924.1), Anaplasma marginale. (MH733242.1, MN567602.1) and Theileria annulata (MT113479) provided a representative data of the isolates circulating in the region and their proximity with available sequences across the world.

CONCLUSIONS

Despite holding much significance to the animal sector, comprehensive disease mapping has yet not been undertaken in several parts of India. The present study provides a blue print of disease mapping, epidemiological correlations and genomic diversity of Babesia bigemina, Anaplasma marginale and Theileria annulata circulating in the region.

Update on prevalence and distribution pattern of tick-borne diseases among humans in India: a review

In the present scenario, tick-borne diseases (TBDs) are well known for their negative impacts on humans as well as animal health in India. The reason lies in their increased incidences due to global warming, environmental and ecological changes, and availability of suitable habitats. On a global basis, they are now considered a serious threat to human as well as livestock health. The major tick-borne diseases in India include Kyasanur forest disease (KFD), Crimean-congo hemorrhagic fever (CCHF), Lyme disease (LD), Q fever (also known as coxiellosis), and Rickettsial infections. In recent years, other tick-borne diseases such as Babesiosis, Ganjam virus (GANV), and Bhanja virus (BHAV) infections have also been reported in India. The purpose of this paper is to review the history and the current state of knowledge of tick-borne diseases in the country. The conclusion of this review is extending the requirement of greater efforts in research and government management for the diagnosis and treatment and as well as prevention of these diseases so that tick-borne disease burden should be minimizing in India.

Reviewing the ecological evidence base for management of emerging tropical zoonoses: Kyasanur Forest Disease in India as a case study

Zoonoses disproportionately affect tropical communities and are associated with human modification and use of ecosystems. Effective management is hampered by poor ecological understanding of disease transmission and often focuses on human vaccination or treatment. Better ecological understanding of multi-vector and multi-host transmission, social and environmental factors altering human exposure, might enable a broader suite of management options. Options may include "ecological interventions" that target vectors or hosts and require good knowledge of underlying transmission processes, which may be more effective, economical, and long lasting than conventional approaches. New frameworks identify the hierarchical series of barriers that a pathogen needs to overcome before human spillover occurs and demonstrate how ecological interventions may strengthen these barriers and complement human-focused disease control. We extend these frameworks for vector-borne zoonoses, focusing on Kyasanur Forest Disease Virus (KFDV), a tick-borne, neglected zoonosis affecting poor forest communities in India, involving complex communities of tick and host species. We identify the hierarchical barriers to pathogen transmission targeted by existing management. We show that existing interventions mainly focus on human barriers (via personal protection and vaccination) or at barriers relating to Kyasanur Forest Disease (KFD) vectors (tick control on cattle and at the sites of host (monkey) deaths). We review the validity of existing management guidance for KFD through literature review and interviews with disease managers. Efficacy of interventions was difficult to quantify due to poor empirical understanding of KFDV-vector-host ecology, particularly the role of cattle and monkeys in the disease transmission cycle. Cattle are hypothesised to amplify tick populations. Monkeys may act as sentinels of human infection or are hypothesised to act as amplifying hosts for KFDV, but the spatial scale of risk arising from ticks infected via monkeys versus small mammal reservoirs is unclear. We identified 19 urgent research priorities for refinement of current management strategies or development of ecological interventions targeting vectors and host barriers to prevent disease spillover in the future.

Molecular and serological detection of Anaplasma infection in carrier cattle in north India

Anaplasma marginale infection in cattle (n = 216) in the states of Uttar Pradesh and Uttarakhand, North India was screened by microscopy and nested-polymerase chain reaction (PCR). Two recombinant proteins viz. major surface protein (MSP) 5 and MSP2 of A. marginale were expressed in Escherichia coli and their potential in the detection of antibodies to Anaplasma species in the cattle was evaluated by immunoglobulin G-enzyme linked immunosorbent assay (IgG-ELISA). The MSP5 IgG ELISA results were compared with competitive (c) inhibition ELISA. Microscopy being the least sensitive diagnostic test detected 12.0% of animals positive for A. marginale infection while nested-PCR detected 87.9% of these animals as positive for A. marginale infection. The recombinant MSP5 antigen showed positive reactivity in 170/190 nested-PCR confirmed positive animals (sensitivity 89.5%) with specificity of 77.0%. In comparison, the recombinant MSP2 antigen showed lesser sensitivity and specificity of 79.0% and 69.2%, respectively. The cELISA was more sensitive and specific than IgG-ELISA. However, molecular detection by msp5 nested-PCR was highly sensitive and reliable for detection of carrier cattle for Anaplasma infection. The study indicated that a large cattle population (87.9%) was carrier for A. marginale infection in this region of the country.

The co-infection with Ehrlichia minasensis, Anaplasma marginale and Anaplasma platys is not associated with anemia in beef cattle in the Brazilian Pantanal

The Anaplasmataceae family is composed of obligatory intracellular Gram-negative bacteria transmitted by arthropod vectors. In Brazil, with the exception of Anaplasma marginale, little is known about the occurrence of other Anaplasma and Ehrlichia species infecting cattle. The present study aimed at investigating the occurrence of Anaplasma spp. and Ehrlichia spp. in beef cattle (Bos indicus) sampled in the Brazilian Pantanal, an area prone to periodic flooding and endemic for bovine trypanosomiasis. Blood samples from 400 cattle were collected and screened by PCR assays based on rrs and dsb genes from Anaplasma spp. and Ehrlichia spp., respectively. Positive samples for Anaplasma spp. were subjected to qPCR assays based on the msp-2 gene and nPCR based on the groEL gene. As a result, 4.75% (19/400) and 48.12% (167/347) were positive for Anaplasma platys and Ehrlichia minasensis, respectively. Besides, positivity of 56.75% (227/400) for A. marginale and seropositivity of 90.75% (363/400) for Trypanosoma vivax were found. A high rate of co-infection was observed (67.25%), from which the co-infection by A. marginale and E. minasensis was more frequently found in calves than cows. Interestingly, none of the animals presenting co-infection showed anemia or other clinical signs. The present study showed, for the first time, the occurrence of A. platys and E. minasensis in beef cattle in the southern Pantanal, as well as a high rate of co-infection by A. marginale, E. minasensis and T. vivax in the sampled animals.

A Multiplex PCR Detection Assay for the Identification of Clinically Relevant Anaplasma Species in Field Blood Samples

The genus Anaplasma (Rickettsiales: Anaplasmataceae), which includes the species Anaplasma capra, Anaplasma bovis, Anaplasma ovis, and Anaplasma phagocytophilum, is responsible for a wide variety of infections in both human and veterinary health worldwide. Multiple infections with these four Anaplasma pathogens have been reported in many cases. We introduce a novel multiplex PCR for the simultaneous detection of A. capra, A. bovis, A. ovis, and A. phagocytophilum, based on species-specific primers against the groEL (A. capra and A. bovis), msp4 (A. ovis), and 16S rRNA (A. phagocytophilum) genes. To verify the specificity of the PCR reactions, we evaluated four sets of primers to analyze samples containing different blood pathogens. The sensitivity of the multiplex PCR was evaluated by amplifying 10-fold dilutions of total genomic DNA extracted from sheep blood infected with A. capra, A. bovis, A. ovis, or A. phagocytophilum. The reproducibility of the assay was evaluated by testing 10-fold dilutions of total genomic DNA extracted from sheep blood infected with these pathogens from 10⁰ to 10^–3 ng/μL per reaction in triplicate on three different days. A total of 175 field blood DNA samples were used to evaluate the reproducibility of multiplex PCR compared with the simplex PCRs. PCR primers used in this study were confirmed to be 100% species-specific using blood pathogens previously identified by other methods. The lower limit of detection of the multiplex PCR with good repeatability enabled the detection of A. capra, A. bovis, A. ovis and A. phagocytophilum at concentrations of 3 × 10^–5, 5 × 10^–7, 2 × 10^–5, and 7 × 10^–7 ng/μL, respectively. There was no significant difference between conventional and multiplex PCR protocols used to detect the four Anaplasma species (P > 0.05). The results of the multiplex PCR revealed that the A. capra groEL gene, the A. bovis groEL gene, the A. ovis msp4 gene, and the A. phagocytophilum 16S rRNA gene were reliable target genes for species identification in clinical isolates, being specific for each of the four target Anaplasma species. Our study provides an effective, sensitive, specific, and accurate tool for the rapid differential clinical diagnosis and epidemiological surveillance of Anaplasma pathogens in sheep and goats.

Ticks and accompanying pathogens of domestic and wild animals of Kerala, South India

The objective of the present study was to detect the chosen nucleotide DNA or RNA sequences of the pathogens in ticks of domestic and wild animals of Kerala, South India based on molecular techniques. Among 602 ticks collected, 413 were from bovines (cattle and buffalo), 26 from goats, 101 from dogs and 62 from wild animals. Amblyomma integrum, Am. gervaisi, Dermacentor auratus, Haemaphysalis bispinosa, Ha. intermedia, Ha. shimoga, Ha. spinigera, Rhipicephalus annulatus, Rh. microplus, Rh. haemaphysaloides and Rh. sanguineus s.l. were identified from various domestic and wild animals of Kerala. The cDNA synthesized from the RNA isolated from fully or partially engorged adult female/nymphal ticks was used as template for the specific polymerase chain reactions (PCR). Out of 602 ticks examined, nucleotide sequences of pathogens were detected in 28 ticks (4.65%). The nucleotide sequences of tick-borne pathogens like Theileria orientalis, Babesia vogeli, Hepatozoon canis, Anaplasma marginale, An. bovis, Rickettsia sp. closely related to Ri. raoultii, Ri. massiliae, Ri. africae and Ri. slovaca were detected. The identification of the previously unreported nucleotide sequences of rickettsial pathogens from India is of particular interest due to their zoonotic significance. The phylogenetic analysis of the major piroplasm surface protein (MPSP) gene of T. orientalis amplified from Rh. annulatus ticks revealed that they were genetically close to type 7, which belong to the highly pathogenic Ikeda group.