Detection of Babesia canis vogeli, Babesia gibsoni and Ehrlichia canis by multiplex PCR in naturally infected dogs in South India

Population genetics of Babesia vogeli based on the mitochondrial cytochrome b gene

The current study aimed at population genetic characterization of B. vogeli based on the cytochrome b (cyt b) gene sequences (≥ 685 bp) available in the GenBank. Phylogenetic trees placed all the sequences of B. vogeli in a single large monophyletic clade; however, it was further divided into two subclades (Bv1 and Bv2). Out of seven nucleotide variations observed between Bv1 and Bv2 subclades, four were synonymous (G92A, C170T, T488C and A659G), and three were non-synonymous (G324A, C438A and G465A) resulting in amino acid substitutions at three places (V108I, L146I and V155I). Within different B. vogeli populations, the nucleotide and haplotype diversities were low. The median-joining haplotype network revealed only two haplotypes (Hap_1 and Hap_2). A geographical sub-structuring was noticed in the B. vogeli populations, with moderate genetic differentiation (FST = 0.05000; P < 0.05) and a very high gene flow (Nm = 4.75) between Indian and Chinese populations. Neutrality tests and mismatch distributions for the Indian population and the overall dataset of B. vogeli indicated a constant population size. This study provides the first insight into the genetic characterization, population genetics and haplotype network of B. vogeli based on the cyt b gene.

Molecular Survey of Tick-Borne Haemoparasites of Dogs by Multiplex Polymerase Chain Reaction from Punjab, India

PURPOSE

Tick-transmitted parasites as Babesia gibsoni, Babesia vogeli, Ehrlichia canis, and Hepatozoon canis are major health concern for dogs. Owing to prevalence and infection severity, there is need of sensitive, specific, and affordable test for their simultaneous detection.

METHODS

Prevalence of B. gibsoni, B. vogeli, E. canis, and H. canis infections was assessed on 719 blood samples by microscopy and multiplex PCR assay targeting 18S rRNA (B. gibsoni & H. canis), ITS1 & 5.8S rRNA (B. vogeli) and VirB9 gene (E. canis). An internal control (canine-actin) was also included to increase the accuracy of assay and effect of associated risk factors with disease prevalence was also studied.

RESULTS

Microscopic prevalence of B. gibsoni, B. vogeli, E. canis and H. canis was 5.0%, 0.1%, 1.4% and 1.0%, respectively, whereas with multiplex PCR assay, the corresponding values were 8.9%, 1.1%, 2.6% and 5.1% besides concurrent infections of B. gibsoni & H. canis (0.4%), B. gibsoni & E. canis (0.4%), E. canis & H. canis (0.3%) and B. gibsoni & B. vogeli (0.1%). Analytical sensitivity of developed assay was 0.1pg (B. gibsoni & H. canis), 0.01pg (B. vogeli), and 1.0pg (E. canis). A ″fair″ (B. vogeli & H. canis) to ″substantial″ (B. gibsoni & E. canis) agreement between two tests was observed with data as statistically significant. Breed, sex and location were significantly associated with B. gibsoni infection.

CONCLUSION

The developed multiplex PCR assay offers a potential solution to detect these pathogens simultaneously, aiding in timely diagnosis and effective disease management in suspected dogs.

Phylogenetic analysis of Ehrlichia species isolated from horses and dogs in Iran

This study aimed to determine the prevalence and phylogenetic analysis of Ehrlichia spp. in horses and dogs in Iran. Blood samples were collected from 400 animals, including 200 horses and 200 dogs, from five different provinces in Iran. Polymerase chain reaction (PCR) was used to detect Ehrlichia spp. based on amplification of the 16S rRNA gene. The semi-nested PCR method was used to amplify the dsb, TRP36, and gltA genes. The results showed that 4.5 % of the samples (3 % horses and 6 % dogs) were positive for Ehrlichia sp. The highest prevalence was observed in Kerman and Khuzestan, while the lowest was found in West Azerbaijan, Golestan, and Mazandaran. The study suggests that the populations of dogs and horses in the country should be considered important factors in the epidemiology of ehrlichiosis. Phylogenetic analysis based on the dsb and TRP36 genes revealed that the prevalent species were E. canis and E. ruminantium.

Canine Babesiosis Caused by Large Babesia Species: Global Prevalence and Risk Factors-A Review

Canine babesiosis is a disease caused by protozoan pathogens belonging to the genus Babesia. Four species of large Babesia cause canine babesiosis (B. canis, B. rossi, B. vogeli, and the informally named B. coco). Although canine babesiosis has a worldwide distribution, different species occur in specific regions: B. rossi in sub-Saharan Africa, B. canis in Europe and Asia, and B. coco in the Eastern Atlantic United States, while B. vogeli occurs in Africa, southern parts of Europe and Asia, northern Australia, southern regions of North America, and in South America. B. vogeli is the most prevalent large Babesia species globally. This results from its wide range of monotropic vector species, the mild or subclinical nature of infections, and likely the longest evolutionary association with dogs. The most important risk factors for infection by large Babesia spp. include living in rural areas, kennels or animal shelters, or regions endemic for the infection, the season of the year (which is associated with increased tick activity), infestation with ticks, and lack of treatment with acaricides.

Multiple blood pathogen infections in apparently healthy sheltered dogs in southern Thailand

In developing countries such as Thailand, free-ranging dogs are frequently involved in road accidents and contribute to the cost of public healthcare. Shelters play a vital role in communities because they help to control the population of unwanted and free-ranging dogs. This study aimed to investigate blood pathogen infection in sheltered dogs, as it is one of the factors contributing to animal welfare. Blood samples were randomly collected from 141 dogs from the largest shelter (approximately 400–500 dogs in total) in southern Thailand. Blood pathogens were detected using both PCR and light microscopy. Four blood pathogens were identified: Anaplasma platys, Ehrlichia canis, Babesia canis vogeli, and Hepatozoon canis. No trypanosomes were detected. The incidence of blood parasite infection was 56.7% (80/141) by PCR, and 28.4% (40/141) by microscopy. E. canis was the most prevalent pathogen, accounting for 46.1% (65/141) of the cases, while multiple infections accounted for 22% (31/141) of the cases. A triple infection with E. canis, A. platys, and B. canis vogeli was observed in 5.7% (8/141) of the cases. Although PCR is far more sensitive than microscopy, it appears to have equivalent specificity. In conclusion, this study reported a high occurrence of blood pathogen infections in clinically healthy sheltered dogs. Many of them were infected with multiple pathogens and may have been infected before entering the shelter. These findings suggest that a blood test is necessary to screen dogs prior to their admission to the shelter to prevent disease transmission and enhance animal welfare.

Van İlindeki Sokak Köpeklerinde Babesia Türlerinin Polimeraz Zincir Reaksiyonu Yöntemi İle Araştırılması

Amaç: Köpek babesiosisi Babesia spp.’ nin neden olduğu hemolitik anemi, splenomegali, trombositopeni ve ateşe neden olabilen kene kaynaklı bir protozoal hastalıktır. Türkiye’de yapılan moleküler çalışmalar soncunda B. canis, B. gibsoni, B. vogeli, B. rossi ve B. vulpes türlerinin varlığı ortaya konulmuştur. Yapılan literatür taramalarına göre Van ilinde yaşayan köpeklerde Babesia türlerini ortaya koyan herhangi bir çalışma bulunmamaktadır. Bu çalışma, Van ilindeki köpeklerde babesiosisin varlığı ve yaygınlığının Polimeraz Zincir Reaksiyonu (PZR) tekniği ile araştırılması amacıyla yapılmıştır. Yöntem: Rastgele seçilen toplam 100 asemptomatik köpeğin vena cephalica antebrachii’lerinden EDTA’lı tüplere kan örnekleri alınmıştır. Alınan örneklerden elde edilen DNA’lar, Babesia spp.’ nin varlığı yönünden 18S ribozomal RNA geninin amplifiye edildiği PZR yöntemi ile araştırılmıştır. Bulgular: Muayene edilen 100 köpeğin PZR sonuçlarına göre hiçbirinde Babesia spp. DNA’sına rastlanmamıştır. Sonuç: Bu çalışma ile Van yöresi sokak köpeklerinde ilk kez Babesia spp. türleri moleküler olarak araştırılmıştır.

Duplex real-time PCR methods for molecular detection and characterization of canine tick-borne haemoparasites from Punjab state, India

Background

Microscopy is a routinely used technique for the diagnosis of canine tick-borne haemoparasitic diseases in various clinical laboratories worldwide. In an attempt to provide better diagnostic assay to the clients for effective management of these diseases duplex real-time PCR assays were applied.

Methods and results

Blood samples (n = 338) aseptically collected from suspected dogs of Central Plain Zone of Punjab state, India were subjected to SYBR Green based real-time duplex PCR assays for simultaneous detection of B. vogeli & E. canis and B. gibsoni & H. canis. Results revealed an overall prevalence rate of canine tick-borne haemoparasites as 54.1%, amongst which H. canis was the predominant (25.4%), followed by B. gibsoni (16.3%), E. canis (10.7%) and B. vogeli (1.8%). Sensitivity and specificity of the duplex assays ranged from 59.04 to 100.0% and 58.12 to 92.52%, respectively and their strength of agreement was ″fair″ with kappa value statistics. A significant (p < 0.05) association between prevalence of B. gibsoni, H. canis and E. canis infection with risk factors like sex, breed, season and location was recorded. The ancestral background of the field isolates of haemoparasites was also studied by phylogenetic analysis of their nucleotide sequences.

Conclusions

SYBR Green dye based duplex real-time PCR assays proved to be highly sensitive, specific, rapid and affordable diagnostic tests for use by clinicians to save the life of pets.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11033-022-07286-4.

Deltamethrin resistant alleles predominate in Rhipicephalus sanguineus sensu lato in South India

Brown dog tick, Rhipicephalus sanguineus sensu lato, an important ectoparasite transmitting several pathogens, is the most common tick species infesting dogs. Control of ticks being central to the control of fatal tick-borne diseases, this study attempted to assess the susceptibility/resistance of brown dog ticks to synthetic pyrethroids, the commonly used acaricides against ticks. Larval packet assay revealed 60% of isolates tested to be resistant and tolerant to deltamethrin as per the resistance factor that ranged from 1 to 53.7. Sequence analysis of the PCR amplified product of domain II S4-5 linker of sodium channel gene in R. sanguineus revealed novel polymorphisms, viz., C190A, G215T and T270C. In domain III S6 region of the gene, a T2134C mutation was observed. Genotyping with allele-specific PCR targeting domain II S4-5 linker region using single larvae revealed that most R. sanguineus larvae in the study population were homozygous resistant (RR) genotypes, followed by heterozygous (RS) and homozygous susceptible (SS) genotypes. A higher proportion of RS genotypes was also observed in domain III S6 region. This first report of genotyping of Indian R. sanguineus to analyse synthetic pyrethroid resistance highlights the need to devise alternate control strategies to reduce the brown dog tick population.

Challenges in Tick-Borne Pathogen Detection: The Case for Babesia spp. Identification in the Tick Vector

The causative agents of Babesiosis are intraerythrocytic protozoa of the genus Babesia. Babesia parasites are present around the world, affecting several mammals including humans, pets and livestock, hence its medical and veterinary relevance. Babesia spp. detection in its invertebrate host is a main point in understanding the biology of the parasite to acquire more knowledge on the host–Babesia–vector interactions, as increasing knowledge of the Babesia lifecycle and babesiosis epidemiology can help prevent babesiosis outbreaks in susceptible mammals. The aim of the present review is to highlight the newest findings in this field, based on a bibliographic compilation of research studies recently carried out for the detection of the main Babesia species found in tick vectors affecting mammalian hosts, including the different tick stages such as adult ticks, larvae, nymphs and eggs, as well as the detection method implemented: microscopic tools for parasite identification and molecular tools for parasite DNA detection by conventional PCR, nested-PCR, PCR-RFLP, PCR-RLB hybridization, real time-PCR, LAMP and RAP assays. Although molecular identification of Babesia parasites has been achieved in several tick species and tissue samples, it is still necessary to carry out transmission experiments through biological models to confirm the vectorial capacity of various tick species.

Molecular tools-advances, opportunities and prospects for the control of parasites of veterinary importance

The recent advancement in genome sequencing facilities, proteomics, transcriptomics, and metabolomics of eukaryotes have opened door for employment of molecular diagnostic techniques for early detection of parasites and determining target molecules for formulating control strategies. It further leads to the introduction of several purified vaccines in the field of veterinary parasitology. Earlier, the conventional diagnostic methods was entirely based upon morphological taxonomy for diagnosis of parasites but nowadays improved molecular techniques help in phylogenetic study and open an another area of molecular taxonomy of parasites with high precision. Control measures based upon targeting endosymbionts in parasites like Dirofilaria immitis is also under exploration in veterinary parasitology. Metagenomics have added an inside story of parasites bionomics which have created havoc in human and animals population since centuries. Omics era is playing a key role in opening the new approaches on parasite biology. Various newer generations of safer vaccines like edible vaccines and subunit vaccines and diagnostic techniques based upon purified immunologically active epitopes have become commercially available against the parasites (helminths, protozoa and arthropod borne diseases). Nowadays, a transgenic and gene knock out studies using RNA interference and CRISPR are also helping in understanding the functions of genes and screening of target genes, which are not available before the advent of molecular tools. Molecular techniques had paramount impact on increasing the sensitivity of diagnostic tools, epidemiological studies and more importantly in controlling these diseases. This review is about the advancements in veterinary parasitology and their impact on the control of these pathogens.

Survey and Molecular Study of Babesia gibsoni in Dogs of Baghdad Province, Iraq

This study aimed to detect Babesia gibsoni (B. gibsoni) in dogs of different ages, sex and breeds in Baghdad province by microscopic and molecular investigations using polymerase chain reaction (PCR), sequencing, and phylogenetic analyses. The present study was investigated B. gibsoni in 310 blood samples of dogs for the period from December 2018 to September 2019 in Baghdad province, Iraq. The molecular study was carried out by using universal primers of Babesia spp. (PIRO-A and PIRO-B) and specific primers of B. gibsoni (BAGIF and BAGIR) products size of 410 bp and 488 bp fragments of 18S rRNA gene respectively. The clinical signs revealed higher percentage and specific clinical signs of B. gibsoni as depression, anorexia, fever, pale mucus membrane, and ticks infestation, however icterus, and dead were low in which only occurred in two dogs out of infected dogs. The PCR assay and microscopic diagnosis revealed the infection rate of B. gibsoni 9 out of 310 (2.9%) in dogs. The sequence data analyses of nine DNA products were 98-100% similar to sequences of 18S rRNA gene of B. gibsoni data available in Gene bank. According to breed, age, and sex, the results revealed a significantly high-risk factor of infection in Husky dogs; B. gibsoni detected in females which was increased non-significantly than males; while the highest occurrence of disease was in young dogs aged three years or less in addition to the above, the infection rate of B. gibsoni was high in spring season. In conclusion, this study was considered the first molecular record of B. gibsoni in Baghdad, Iraq documented no differences in diagnosis by blood smear and conventional PCR to amplify of 18S rRNA gene and partial sequencing of B. gibsoni with low-cost method and easily done.

Development and application of multiplex PCR assay for the simultaneous detection of Babesia vogeli, Ehrlichia canis and Hepatozoon canis in dogs

A multiplex PCR assay was standardized and evaluated to simultaneously detect the DNA of Babesia vogeli, Ehrlichia canis and Hepatozoon canis in dogs of selected districts of Punjab state, India. Amplicons of 602 bp, 380 bp and 306 bp corresponding to B. vogeli (18S rRNA gene), E. canis (VirB9 gene), and H. canis (18S rRNA gene) were obtained, without any non-specific amplification. The results of multiplex PCR assay were further compared with the corresponding singleplex PCR assay. The diagnostic sensitivity and specificity of multiplex PCR assay with respect to singleplex PCR assay in the detection of B. vogeli, E. canis and H. canis varied from 50% to 100% and 92.08% to 98.79%, respectively revealing "moderate" to "very good" agreement by kappa value statistics. Blood samples from 322 dogs collected from selected districts of Punjab state, India, when screened by microscopy revealed the prevalence of B. vogeli, E. canis and H. canis as 0.31%, 0.93% and 1.86%, respectively whereas with multiplex PCR assay the values were 0.93%, 10.24% and 4.65%, respectively, with concurrent infection of E. canis & H. canis (1.86%) and B. vogeli & E. canis (0.31%). The diagnostic sensitivity and specificity of multiplex PCR assay with respect to microscopy in the detection of B. vogeli, E. canis and H. canis varied from 69.15% to 100% and 85.11% to 92.33%, respectively revealing "fair" agreement by kappa value statistics and the data was statistically significant. The analytical sensitivity of multiplex PCR assay in the detection of B. vogeli, E. canis and H. canis was 100 pg, 10 pg and 0.1 pg, respectively, whereas the values for the singleplex counterpart were 0.1 pg, 0.01 pg and 0.01 pg. Furthermore, various risk factors viz. age, breed, sex, season and districts were non-significantly associated with the prevalence of these haemoparasites except for E. canis that revealed a significant association with districts by multiplex PCR assay. Therefore the multiplex PCR assay developed may be useful in identification of the aetiological agents of these diseases during their early phase, which may in turn be useful in development of better health care and appropriate treatment of suspected dogs, particularly in endemic regions.

Babesia canis spp. in dogs in Baghdad Province, Iraq: First molecular identification and clinical and epidemiological study

AIMS

The aim of this study was to investigate babesiosis in dogs of different breeds and ages and of both sexes in Baghdad Province by molecular detection of Babesia canis using conventional polymerase chain reaction (PCR) and sequencing followed by phylogenetic analyses.

MATERIALS AND METHODS

Blood samples were collected from 310 dogs of different ages and breeds, and of both sexes in different areas of Baghdad Province from December 2018 to September 2019; during clinical examinations, body temperature, pulse, respiratory rate, and signs of diseases were recorded. PCR was used to amplify a specific 450-bp fragment of the 18S rRNA gene of B. canis. PCR products were sequenced, and MEGA 6.0 software was used for analysis. Chi-square and odds ratio tests were used to investigate the prevalence and risk factors of babesiosis.

RESULTS

Clinical signs of babesiosis included paleness or icterus of the mucus membranes, tick infestation, and febrile illness during the acute and subacute phase. The prevalence of infection with B. canis was 5.1%, with the higher prevalence in male dogs and in dogs <3 years of age. Huskies were more likely to be infected than other dogs. Infection prevalence was highest in April and June and was higher in spring and summer than in winter. Using sequence data, 14 isolates of Babesia canis canis and one isolate of each Babesia canis rossi and Babesia canis vogeli were identified. Phylogenetic analyses of B. canis canis revealed that three shared clades and several isolated lineages were similar to other isolates (97-99% similarity), whereas B. canis vogeli and B. canis rossi showed similarities of 98% and 99% with isolates from other geographical regions.

CONCLUSION

This study provides the first molecular record and phylogenic analysis of B. canis in dogs in Iraq, and it will be valuable for confirming clinical signs and studying epidemiological risk factors of babesiosis in dogs.

Genetic Diversity of Canine Babesia Species Prevalent in Pet Dogs of Punjab, Pakistan

Simple Summary

Babesiosis is caused by the intra-erythrocytic Babesia species in dogs. Different species are reported worldwide. The present study was conducted on pet dogs of two districts of Punjab, Pakistan, including Lahore and Narowal. Conventional microscopic and molecular tests, including conventional and nested PCR, were used for identification of diseased dogs and prevalent species. About 42% of dogs were tested positive for babesiosis and only two species including Babesia canis and gibsoni were prevalent.

Abstract

Canine babesiosis is a serious threat to dogs’ health worldwide, caused by the intra-erythrocytic Babesia species. The present study was carried out in pet dogs presented at three clinics of Lahore and one of Narowal in Punjab, Pakistan. Two hundred blood samples (50 from each clinic) were collected and screened by microscopy for Babesia spp. Out of 200 samples, 84 (42%) were found to be positive for babesiosis. The highest number of positive cases (50%) was recorded in dogs at Narowal clinic. Non-significant variation (p > 0.05) was observed in the prevalence of babesiosis in dogs in relation to sex and age. Positive samples were further confirmed by a polymerase chain reaction using 18S-rRNA genus-specific and species-specific primers. Amplicons were further analyzed by nucleotide sequencing for genetic diversity. Babesia canis and gibsoni were confirmed by genome sequencing in all diseased dogs. These isolates closely resembled each other, but differed from previous reported strains. In conclusion, pet dogs suffering from babesiosis were infected with B. canis and gibsoni, while in other countries, other Babesia species are also prevalent.

Evaluation of multiplex PCR assay for detection of Babesia spp, Ehrlichia canis and Trypanosoma evansi in dogs

A multiplex PCR test was evaluated to detect the DNA of three important dog haemoparasites by comparing with singular PCR counterpart on clinical blood samples of dogs in and around Chennai, Tamil Nadu, India. Initial screening of samples was done by microscopic examination of peripheral blood smear and singular PCR and those found exclusively positive for Babesia spp, Ehrlichia canis and Trypanosoma evansi and concurrent infections were used to standardize multiplex PCR. Amplicons of 619 bp, 377 bp and 227 bp corresponding to Babesia spp (18S rRNA gene), E. canis (VirB9 gene), and T.evansi (VSG gene) respectively were amplified, without any non-specific amplification. The laboratory sensitivity (91.7% to 100%) and specificity (100%) of the multiplex PCR were calculated using 'true positive' and 'true negative' dog blood samples obtained in the initial screening process. Clinical blood samples from 287 dogs were screened using singular PCR and multiplex PCR tests for the presence of genome of Babesia spp, E. canis and T. evansi. The multiplex PCR was found to have high level of diagnostic specificity (97.5%-100%) in the detection of all three dog blood parasites and high level of diagnostic sensitivity (95%) in the detection of T. evansi from field level clinical blood samples compared to the singular PCR. However, the diagnostic sensitivity of the multiplex PCR was found to be low to moderate (40.45%-66.7%) in detection of Babesia spp and E. canis from field level clinical blood samples. The strength of agreement between singular and multiplex PCR assays was 'moderate' (0.445), 'good' (0.708) and 'very good' (0.968) in detection of DNA of Babesia spp, E. canis and T. evansi. The multiplex PCR was found to be 10 fold less sensitive in comparison with the singular PCR counterpart.

Molecular evidence of haemoparasites in ixodid ticks of dogs- first report in India

The distribution of ixodid ticks of the genera Rhipicephalus and Haemaphysalis spp. in tropical regions of India contributes to many serious tick-borne parasitic and rickettsial infections in domestic and wild canines. A preliminary molecular survey of the most prevalent haemoparasites in ixodid ticks of carnivores in Kerala, South India was undertaken using multiplex PCR. Babesia vogeli, B. gibsoni and Ehrlichia canis could be detected in R. sanguineus ticks, while H. bispinosa harboured B. gibsoni alone. Future investigations including transmission trials are to be undertaken to prove the vector potentiality of these ticks in this geo-climatic zone.

Molecular detection of Hepatozoon canis in dogs from Kerala

India has a wide range of agro-climatic zones which is highly conducive for a diverse range of vectors and canines are continuously exposed to the risk of spectrum of tick borne protozoan diseases. The brown dog tick, Rhipicephalus sanguineus is widely prevalent among dogs in Kerala and there is a high prevalence of this tick transmitted Babesia and Ehrlichia spp. infection. However, the incidence of Hepatozoon canis transmitted by the same tick species had not been reported in the state since 2004. Preliminary screening of client owned dogs revealed six dogs to be positive for typical gelatin capsule shaped gamonts of H. canis within neutrophils in blood smear by microscopic examination. A PCR assay was standardized to amplify a specific 737 bp fragment of 18S rRNA gene of H. canis. Phylogenetic analysis revealed closest relationship with West Indies isolate deposited at GenBank database. The present study records the molecular detection of this haemoparasite in the state, for the first time.