Babesia canis vogeli: a novel PCR for its detection in dogs in Australia

Molecular detection and characterization of Anaplasma marginale and Babesia canis vogeli infecting dogs in Luxor, Egypt

Tick-borne diseases in animals are increasing rapidly worldwide, but there is insufficient information about tick-borne diseases infecting dogs in southern Egypt. Thus, in the current study, we detected the presence of Anaplasma marginale (A. marginale) and Babesia canis vogeli (B. canis vogeli) in the blood of dogs. The results revealed that 4/100 (4%) were positive, and a higher infection rate was found in males (75%), than females (25%). The phylogenetic analysis for the major surface protein 4 (msp4) gene in this study was compared with amplicons separate from other reported isolates with alignment by identity 100% with cattle and camels from Egypt, and the phylogenetic analysis for the B. canis vogeli small subunit ribosomal RNA (SSU rRNA) gene in this study identified identity by 99.89% with dogs from Egypt. This report is considered the first report in southern Egypt about A. marginale in dogs based on the sequence analysis of the msp4 gene, providing new data for the classification and identification of A. marginale in dogs compared to A. marginale isolated from other animals in southern Egypt.

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.

Canine babesiosis among working dogs of organised kennels in India: A comprehensive haematological, biochemical, clinicopathological and molecular epidemiological multiregional study

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First holistic study on canine babesiosis among working dogs from India.

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B. gibsoni babesiosis is posing a diagnostic & therapeutic challenge in this country.

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Atypical babesiosis (MODS, DIC) are being maidenly documented from this country.

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Simple PCR assay results were statistically found to be significantly false negative.

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Nested PCR assay to be relied upon as screening and for epidemiological studies.

Canine babesiosis is a serious disease among tick-borne haemoprotozoan diseases, globally. The present study was envisaged for carrying out thorough investigation of the disease among working dogs of organised kennels situated in different agro-climatic zones of India as comprehensive understanding of the disease from this country was pertinently lacking. During the study period of three years (2012–2014), 330 dogs suspected for babesiosis were examined for clinicopathology by their physical examination, haematological and biochemical parameters estimation, while the detection of apicomplexan parasites was confirmed by using various diagnostic techniques i.e. by conventional microscopy, by two different Babesia specific 18S rRNA based PCR protocols (conventional/simple PCR and nested PCR assays) followed by sequencing of obtained PCR amplicons for Babsesia spp. identification. Out of 330 clinical cases screened 5.15% (17/330), 9.09% (30/330) and 15.45% (51/330) were found to be positive in microscopic examination, simple- and nested- PCR assay, respectively. Comparative statistical analyses of these diagnostic assay results revealed that significant difference exists among the three diagnostic methodologies and thus it is recommended that the nested PCR technique be relied upon as a screening molecular assay and also for epidemiological studies of the disease in this country. Phylogenetic analysis based on 18S rRNA depicted the monophyletic nature and clonal expansion among all the B. gibsoni, under study. Sequencing results of PCR amplicons revealed that B. gibsoni has predominantly established itself over B. vogeli as former was incriminated in 47 cases while latter was confirmed in only four animals. Based on the clinical severity, these 51 affected animals were classified into three main groups’ of 17 animals each viz., apparently healthy-, simple or uncomplicated babesiosis- and atypical or complicated babesiosis- group. Haematological and biochemical profiling of these dogs confirmed the characteristics findings of infection by both the Babesia spp. It was observed that the infection by small form of Babesia (B. gibsoni) is posing a significant therapeutic challenge and chemosterilization by commonly prescribed anti-protozoal drugs was not achieved as clinical relapses were often observed. The clinical signs, sequence based confirmation and severity of the infection suggested that there is a positive selection of B. gibsoni (smaller form) over B. vogeli (larger form) in this country and raises serious concerns as prognosis in former is considered to be poor compared to latter. Thus, these findings have opened new paradigms for planning of pragmatic control strategies against this emerging canine health problem.

Vector-borne and zoonotic diseases of dogs in North-west New South Wales and the Northern Territory, Australia

Background

Vector-borne diseases of dogs in Australian Aboriginal communities are relatively unexplored. These dogs represent a unique group with variable ecto- and endo-parasitic burdens, nutritional stresses and a general lack of veterinary intervention. We investigated haemoprotozoal and bacterial pathogen prevalences in relation to erythrocyte and platelet numbers in dogs from North-West New South Wales (N-W NSW) and the Northern Territory (NT; Central Australia).

Methods

Real-time PCR (qPCR) amplification of Anaplasma platys, Babesia vogeli, Mycoplasma haemocanis, Candidatus Mycoplasma haematoparvum and Bartonella spp., serological screening for Coxiella burnetii, and Bartonella spp. and haematological analyses were performed on dogs from the two cohorts (96 dogs in total). Brucella suis serology was determined additionally for the N-W NSW cohort.

Results

Anaplasma platys (n = 26 dogs), Babesia vogeli (n = 7), Candidatus Mycoplasma haematoparvum (n = 10 dogs), and Mycoplasma haemocanis (n = 14) were detected in the sample population (n = 96) using qPCR. There were significant associations between (i) A. platys and anaemia (OR 8.7, CI 2.4–31.7; P < 0.001), thrombocytopenia (OR 12.1, CI 3.4–43.2; P < 0.001) and breed (OR 16.1, CI 2.1–121.5; P = 0.007), and (ii) between B. vogeli and anaemia (OR 11.8, CI 2.3–61.6; P = 0.003). Neither protozoal nor bacterial DNA loads, estimated using qPCR, were positively correlated with anaemia or thrombocytopenia. Haemotropic mycoplasmas were not associated with any haematologic abnormality. Four dogs from the NT were seropositive for Coxiella burnetii, while no dogs were seropositive for Brucella suis or to a panel of Bartonella spp. antigens. Despite directed efforts, Bartonella DNA was not detected in blood from any of the cohorts studied. A sample of dogs from the NT recruited specifically for Bartonella α-proteobacteria growth medium enrichment blood culture were also Bartonella PCR negative.

Conclusions

Vector-borne pathogens occur in dogs free ranging near Aboriginal communities, with higher detection rates in NT than N-W NSW. The preponderant haematologic abnormalities were anaemia and thrombocytopenia, likely attributable to A. platys and B. vogeli infections, but also probably affected by nutritional, parasitic, lactational and environmental stressors. The absence of Bartonella spp. is of importance to the Australian setting, and work needs to be extended to tropical coastal communities where fleas are present as well as ticks. Dogs living in and around Aboriginal communities may provide valuable sentinel information on disease infection status of human public health significance.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-017-1169-2) contains supplementary material, which is available to authorized users.

First detection and molecular identification of Babesia gibsoni from Rhipicephalus sanguineus ticks

Babesia gibsoni was firstly identified in Rhipicephalus sanguineus ticks infested on dogs in Asia. A total of 1195 ticks collected from veterinary practitioners and pet clinics were examined for Babesia by nested-polymerase chain reaction assay based on the 18S small subunit ribosomal RNA (ssrRNA) gene. Babesia infection was detected in nymph, male and female ticks with an infection rate of 2.42%, 0.98% and 1.97%, respectively. Sequence and phylogenetic analysis revealed that these Babesia spp. were genetically affiliated to the same clades within the genospecies of B. gibsoni and B. vogeli, and can be discriminated from other genospecies of Babesia. Intra- and inter-species analysis based on the genetic distance (GD) values indicated a lower level in B. gibsoni (GD<0.011) compared with other genospecies of Babesia (GD>0.106) and out-group protozoa (GD>0.244). This study provides the first molecular evidence of B. gibsoni identified in nymphs of R. sanguineus ticks in Asia, and further confirms the detection of B. vogeli in nymphs and adults of R. sanguineus in northern Taiwan. The epizootiological significance of canine Babesia spp. transmitted by R. sanguineus tick needs to be further identified.

First detection and molecular identification of Babesia vogeli from Rhipicephalus sanguineus (Acari: Ixodidae) in Taiwan

A total of 578 Rhipicephalus sanguineus ticks collected from dogs in Taiwan were examined for Babesia by species-specific polymerase chain reaction assay based on the 18S small subunit ribosomal RNA (ssrRNA) gene. Babesia DNA was detected in 1.04 % (6/578) of Rh. sanguineus ticks. Phylogenetic analysis revealed that these Babesia spp. were genetically linked to the same clade within the genospecies of Babesia vogeli and could be discriminated from other genospecies of Babesia. Intra-species analysis based on the genetic distance values indicated a lower level (0.079) compared with other genospecies of Babesia (GD > 0.094) and out-group protozoa (GD > 0.236). This study provides the first molecular evidence of B. vogeli detected and identified in various stages of Rh. sanguineus ticks removed from dogs in Taiwan. Detection of Rh. sanguineus in flat male ticks may imply the possible mechanism of transstadial transmission in Rh. sanguineus ticks. The vector competence and the diversity of Babesia species harbored by Rh. sanguineus ticks need to be further investigated.

Optimization of a molecular method for the diagnosis of canine babesiosis

Babesiosis is a hemolytic disease caused by protozoans of the genus Babesia (Apicomplexa). This disease occurs worldwide and is transmitted by ticks to a variety of mammals, including humans. The objective of the present study was to optimize a molecular approach for the detection of a fragment of 18S rDNA of Babesia canis, Babesia vogeli, Babesia rossi or Babesia gibsoni based on a single semi-nested Polymerase Chain Reaction (PCR), and compare the efficiency of this approach with that of a simple PCR protocol. To this end, 100 blood samples collected from dogs with suspected hemoparasite infections were analyzed. A comparison of the results of simple PCR and semi-nested PCR indicated a highly significant difference (p value = 0.0000). While only five (5%) of the samples tested positive using the simple protocol, 22 (22%) were positive using the snPCR technique. The results of this study reinforce the findings of previous studies, which have demonstrated the greater sensitivity of tests based on nested or semi-nested PCR. Therefore, to avoid false-negative results due to low levels of parasitemia, we suggest the preferential use of this protocol in epidemiological studies of canine babesiosis, particularly those that require reliable estimates of the prevalence of infection.

Babesia infection in naturally exposed pet dogs from a north-eastern state (Assam) of India: detection by microscopy and polymerase chain reaction

The objective of the study was to detect Babesia infections in pet dogs of a north-eastern state of India. The diagnostic efficacy of Babesia infection by polymerase chain reaction (PCR) technique has been compared with microscopy examination. For this, a total of 111 blood samples of pet dogs presented at clinical complex of the College of Veterinary Science, Guwahati, Assam with clinical signs suspected for Babesia infection subjected to the study. A total of 44 (39.63 %) dogs were diagnosed as positive for Babesia infections after microscopic examination. Among these, Babesia canis infection was diagnosed in 5 dogs (4.50 %) and B. gibsoni infection in 39 (35.13 %) dogs microscopically in Giemsa stained blood smears. Molecular diagnosis using PCR detected 63 (56.75 %) dogs positive for Babesia infection. Single infection with B. canis was found in 9 (8.10 %) dogs while B. gibsoni alone was detected in 3 (2.70 %) dogs. Mixed infections by both these species were detected in 51 (45.94 %) dogs. Overall, PCR detected 54 (48.64 %) dogs as B. gibsoni and 60 (54.05 %) dogs as B. canis positive.

Clinical management of canine babesiosis

OBJECTIVE

To review and summarize current information regarding epidemiology, pathogenesis, and pathophysiology leading to the various clinical syndromes associated with canine babesiosis. Diagnosis, treatment, preventative strategies, and zoonotic implications are discussed.

ETIOLOGY

Babesiosis is caused by hemoprotozoa of the genus Babesia. Numerous species of Babesia exist worldwide. An increased incidence of babesiosis is described, especially in North America. The babesial organism spends the majority of its life cycle within the erythrocyte of the definitive host, resulting in hemolysis, with or without systemic complications.

DIAGNOSIS

Definitive diagnosis depends on direct visualization of the organism on blood smear or polymerase chain reaction. A positive serologic antibody test indicates exposure with or without active infection.

THERAPY

Antiprotozoal drugs, antimicrobials, and supportive care are the mainstays of babesiosis therapy.

PROGNOSIS

Prognosis depends on the severity of disease, which in turn depends on both organism and host factors. Clinical syndromes associated with a poorer prognosis include red biliary syndrome, acute renal failure, acute respiratory distress syndrome, neurologic dysfunction, acute pancreatitis, cardiac dysfunction, and hypoglycemia.

Molecular survey of Babesia canis in dogs in Nigeria

An epidemiological study of Babesia canis in dogs in Nigeria was performed. Four hundred blood samples collected from dogs in Nigeria were investigated using nested PCR and sequence analysis. On nested PCR screening, nine samples (2.3%) produced a band corresponding to a 698-bp fragment indicative of B. canis infection. Sequence analysis of the PCR products identified eight samples (2.0%) as B. canis rossi and the ninth (0.3%) as B. canis vogeli. This is the first report of the prevalence of B. canis rossi and B. canis vogeli in dogs in Nigeria.

Assessment of primers designed for the subspecies-specific discrimination among Babesia canis canis, Babesia canis vogeli and Babesia canis rossi by PCR assay

Canine babesiosis is an infectious disease caused by either Babesia gibsoni or Babesia canis protozoans. The latter is also classified under three different phylogenetic groups, referred to as subspecies B. canis canis, B. canis vogeli and B. canis rossi. The objective of the present study was to validate and standardize a PCR assay to discriminate the organisms at the subspecies level. First, the reference sequences of the 18S rRNA, 5.8S rRNA and 28S rRNA genes, including the internal transcribed spacer 1 (ITS1) and 2 (ITS2) of the most common species and subspecies of the genus Babesia were retrieved from the GenBank database. Subspecies-specific primers (BAB3, BAB4 and BAB5) and one genus-specific primer were designed from the alignment of the sequences. The PCR assays were evaluated in three different combinations of primer pairs in order to assure complete specificity for each reaction. The results of the tests had demonstrated effectiveness of the novel primer pairs BAB1/BAB3, BAB1/BAB4 and BAB1/BAB5 for the amplification of the subspecies-specific target fragments of 746 bp (B. c. canis), 546 bp (B. c. vogeli) and 342 bp (B. c. rossi) by PCR. The original enzymatic amplification assays with novel primers reported in this paper were confirmed to be a reliable tool for the specific discrimination among B. canis subspecies by single-step PCR assays.

Canine babesiosis: A Brazilian perspective

Canine babesiosis is highly endemic in Brazil, caused by Babesia canis and Babesia gibsoni, both transmitted by Rhipicephalus sanguineus ticks. The present review argues for a more adequate method of characterizing the Babesia species infecting dogs and cats in different Brazilian endemic zones. It advocates for a comprehensive understanding of the biology of R. sanguineus ticks under Brazilian conditions in order to define the more effective preventive strategies against canine babesiosis and calls for partnerships between the public and private sectors for research on canine babesiosis and other vector-borne diseases in Brazil.