Detection and molecular identification of Hepatozoon canis and Babesia vogeli from domestic dogs in Palestine

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.

Screening and phylogenetic characterization of tick-borne pathogens in a population of dogs and associated ticks in Egypt

Background

The incidence or recurrence of tick-borne diseases (TBDs) in animals and humans is increasing rapidly worldwide, but there is insufficient information about TBDs infecting dogs in Egypt. Thus, the present study was conducted to screen and genetically identify tick-borne pathogens (TBPs) in dogs and associated ticks by microscopic examination and polymerase chain reaction (PCR).

Methods

In Cairo and Giza governorates, 208 blood samples were collected from dogs of different breeds, ages, and sex. In addition, 1266 dog-associated ticks were collected (546 ticks were used to prepare hemolymph smears, and 720 ticks were kept in 70% ethanol until PCR analysis). PCR was applied to 124 dog blood samples and 144 tick pools prepared from 720 ticks.

Results

All ticks collected from dogs were Rhipicephalus sanguineus (s.l.). Microscopic examination revealed that TBP prevalence among dogs was 23.56% (49/208), including Anaplasma and Ehrlichia with 11.1% (23/208) and Babesia canis with 8.2% (17/208). Hepatozoon canis was not detected in blood smears. Co-infections with two pathogens were visible in 4.33% (9/208) of examined dogs. The prevalence of TBPs in hemolymph smears was 45.97% (251/546) including 35.89% (196/546) for H. canis, 8.1% (44/546) for B. canis, and 2.01% (11/546) for Anaplasmataceae (A. phagocytophilum, A. marginale, A. platys, and E. canis). The overall molecular prevalence rate of TBPs was 25.81% and 29.17% in the blood of examined dogs and in ticks, respectively. The molecular prevalence of Anaplasmataceae family, Babesia canis, and H. canis in dog blood samples was 19.35%, 6.45%, and 0.0%, respectively, while in ticks, it was 20.83%, 5.55%, and 2.8%, respectively. A sequential analysis identified six different species of TBPs, namely B. canis vogeli, Hepatozoon canis, A. phagocytophilum, A. marginale, A. platys, and E. canis. The obtained sequences were submitted to GenBank and assigned accession numbers.

Conclusions

The present study detected a wide range of TBPs (B. canis, H. canis, A. platys, A. phagocytophilum, A. marginale, and E. canis) that are considered a threat to domestic animals and humans in Egypt. Hepatozoon canis and A. marginale were reported in dogs and associated ticks for the first time in Egypt.

Graphical Abstract

Traditional and molecular techniques were used to screen domestic dogs and attached ticks for TBPs.

A wide range of TBPs in dogs and attached ticks was detected in Egypt.

Some accidental pathogens, such as A. marginale from other hosts, were identified in dogs.

Some canine isolates from Anaplasmataceae family have high homology to those isolated from humans.

Ticks and Tick-Borne Infections of Dogs in Two Jordanian Shelters

Shelters in Jordan accommodate a huge number of dogs, which are rescued as stray dogs from different cities of the country, but their health receives almost no attention. The aim of this study was to examine tick infestation as well as tick-borne protozoa and bacteria of 80 randomly sampled dogs in two Jordanian shelters. Ticks identified as Rhipicephalus sanguineus sensu lato were found on 14 out of 27 animals in a shelter. No ticks were found on dogs in the other shelter. A total of 42 (52.5% [95% confidence interval: 41.7-63.1]) dogs were infected with one or two pathogens. The DNA of three protozoal (Hepatozoon canis, Babesia vogeli, and Babesia negevi) and two bacterial (Anaplasma platys and Candidatus Bartonella merieuxii) species were detected in the blood samples. To the best of the authors' knowledge, except for H. canis, these species are reported for the first time from Jordan.

Molecular Survey of Vector-Borne Pathogens of Dogs and Cats in Two Regions of Saudi Arabia

Dogs and cats play an important role as reservoirs of vector-borne pathogens, yet reports of canine and feline vector-borne diseases in Saudi Arabia are scarce. Blood samples were collected from 188 free-roaming dogs and cats in Asir (70 dogs and 44 cats) and Riyadh (74 dogs), Saudi Arabia. The presence of Anaplasma spp., Bartonella spp., hemotropic Mycoplasma spp., Babesia spp., and Hepatozoon spp. was detected using a multiplex tandem real-time PCR. PCR-positive samples were further examined with specific conventional and real-time PCR followed by sequencing. Dogs from Riyadh tested negative for all pathogens, while 46 out of 70 dogs (65.7%) and 17 out of 44 cats (38.6%) from Asir were positive for at least one pathogen. Positive dogs were infected with Anaplasma platys (57.1%), Babesia vogeli (30%), Mycoplasma haemocanis (15.7%), and Bartonella henselae (1.4%), and cats were infected with Mycoplasma haemofelis (13.6%), Candidatus Mycoplasma haemominutum (13.6%), B. henselae (9.2%), and A. platys (2.27%), all of which are reported for the first time in Saudi Arabia. Co-infection with A. platys and B. vogeli was detected in 17 dogs (24.28%), while coinfections were not detected in cats. These results suggest that effective control and public awareness strategies for minimizing infection in animals are necessary.

Infection with Babesia canis in dogs in the Algiers region: Parasitological and serological study

Background and Aim:

Canine babesiosis is a vector-borne disease transmitted by ticks of the Ixodidae family. The effects of infection in dogs can range from the subclinical to the severe lethal form. This study aimed to make an original contribution to the knowledge of circulating species of Babesia spp. in dogs in the region of Algiers as well as mechanisms and risk factors for their transmission.

Materials and Methods:

An epidemiological study was carried out on 189 blood samples taken from dogs from April 2015 to January 2016. The samples taken underwent parasitological by Giemsa-stained blood smear and serological analyzes by indirect fluorescent antibody test (IFAT). The ticks were looked on all the dogs taken.

Results:

Giemsa-stained blood smears revealed the presence of two groups of parasites of the genus Babesia: Large Babesia (3/25, 12%) and small Babesia (22/25, 88%). The IFAT at a dilution of 1/32 showed an overall seroprevalence with Babesia canis of 17.98% (95% confidence interval 11.53-22.46). The distribution of the antibody titers for the positive samples showed that of the 34 positive sera with a titer ≥1/32, 28 sera remained positive at a dilution of 1/64 (14.81%), 22 at a dilution of 1/128 (11.64%) and 15 sera remained positive at a dilution of 1/256 (7.93%). Although seroprevalence varied according to canine population (20% and 19.49% in pet dogs and canine pound dogs, respectively, and 6.66-0% in farm dogs and hunting dogs, respectively), statistical analysis showed no significant differences between populations. The antibody titers obtained after several dilutions showed that 22 canine pound dog sera remained positive at a dilution of 1/128 compared to pet dogs and farm dogs which ceased to be positive at the dilution of 1/64. The comparison between the two diagnostic methods showed a strong agreement between the parasitological examination by blood smear and the serological method by IFAT. However, IFAT was much more sensitive. The analysis of risk factors, which may influence B. canis seroprevalence, has shown the influence of age, tick presence, and season. Finally, of the 242 ticks collected from a total of 59 dogs, only one tick species was identified , Rhipicephalus sanguineus.

Conclusion:

This study indicates a frequent circulation of species of Babesia in the dog in the Algiers region and R. sanguineus was the only tick identified.

A new piroplasmid species infecting dogs: morphological and molecular characterization and pathogeny of Babesia negevi n. sp

Introduction

Babesiosis is a protozoan tick-borne infection associated with anemia and life-threatening disease in humans, domestic and wildlife animals. Dogs are infected by at least six well-characterized Babesia spp. that cause clinical disease. Infection with a piroplasmid species was detected by light microscopy of stained blood smears from five sick dogs from Israel and prompted an investigation on the parasite’s identity.

Methods

Genetic characterization of the piroplasmid was performed by PCR amplification of the 18S rRNA and the cytochrome c oxidase subunit 1 (cox1) genes, DNA sequencing and phylogenetic analysis. Four of the dogs were co-infected with Borrelia persica (Dschunkowsky, 1913), a relapsing fever spirochete transmitted by the argasid tick Ornithodoros tholozani Laboulbène & Mégnin. Co-infection of dogs with B. persica raised the possibility of transmission by O. tholozani and therefore, a piroplasmid PCR survey of ticks from this species was performed.

Results

The infected dogs presented with fever (4/5), anemia, thrombocytopenia (4/5) and icterus (3/5). Comparison of the 18S rRNA and cox1 piroplasmid gene sequences revealed 99–100% identity between sequences amplified from different dogs and ticks. Phylogenetic trees demonstrated a previously undescribed species of Babesia belonging to the western group of Babesia (sensu lato) and closely related to the human pathogen Babesia duncani Conrad, Kjemtrup, Carreno, Thomford, Wainwright, Eberhard, Quick, Telfrom & Herwalt, 2006 while more moderately related to Babesia conradae Kjemtrup, Wainwright, Miller, Penzhorn & Carreno, 2006 which infects dogs. The piroplasm forms detected included tetrads (Maltese cross), merozoite and trophozoite stages whose average size was larger than stages of other canine Babesia spp. belonging to the Babesia (s.l.) and B. gibsoni Patton, 1910, and smaller than other canine Babesia (sensu stricto) spp. Of 212 O. tholozani ticks surveyed, 11 (5.2%) harbored DNA of the new species of Babesia.

Conclusions

Babesia negevi n. sp. is described based on morphological and genetic characterization and phylogenetic analyses. The species is named after the Negev desert of southern Israel, where the first infected dog originated from. Despite co-infection in four dogs, the fifth dog had fatal disease attesting that B. negevi n. sp. infection requires clinical attention. Incriminating O. tholozani or another tick species as the vector of Babesia negevi n. sp., would require additional studies.

Molecular Detection of Theileria ovis and Theleiria equi in Livestock from Palestine

Theileria and Babesia are intracellular protozoan parasites infecting a wide range of animals. In Palestine, there is limited information on the prevalence of Theileria and Babesia spp. in livestock. We used PCR of the 18S ribosomal RNA gene followed by DNA sequencing to detect and identify parasite DNA in blood samples from sheep (n = 49), goats (n = 48), horses (n = 40), camels (n = 34), donkeys (n = 28) and mules (n = 2) from four districts of Palestine. DNA of T. ovis and T. equi was detected in 19 and 2 ovine blood samples, respectively. None of the camels, donkeys, and goats were positive for T. ovis. Sheep had a significantly higher rate of infection than other animals (P < 0.05). Theileria ovis is highly prevalent in sheep, while T. equi DNA was detected in a small proportion of the equids in Palestine.

Comparison of conventional polymerase chain reaction and routine blood smear for the detection of Babesia canis, Hepatozoon canis, Ehrlichia canis, and Anaplasma platys in Buriram Province, Thailand

Background and Aim:

Dog blood parasites are important tick-borne diseases causing morbidity and mortality in dogs worldwide. Four dog blood parasites species are commonly found in Thailand: Babesia canis, Hepatozoon canis, Ehrlichia canis, and Anaplasma platys. They are transmitted easily by tick species. However, there is little prevalence data available in Thailand. Diseases presentation of blood parasites infection is similar, but the treatment of each species is different. Current diagnosis mainly relies on microscopic examination of a stained blood smear, which has low sensitivity. Therefore, accurate diagnosis is important. This study aims to evaluate the efficacy of the conventional polymerase chain reaction (PCR) method and routine blood smears in the detection of four blood parasites species in dogs from Buriram Province, Thailand.

Materials and Methods:

In total, 49 EDTA-blood samples were collected from dogs in Buriram Province, Thailand. Blood parasite infection was compared using the Giemsa-stained blood smear technique to identify the parasite under a 100× oil immersion with PCR amplification of the 18S rDNA gene of B. canis and H. canis and the 16S rDNA gene of E. canis and A. platys.

Results:

Only one dog out of 49 was positive for H. canis based on microscopic examination whereas the PCR results showed that 2.04% (1/49), 4.08% (2/49), 36.73% (18/49), and 30.61% (15/49) of dogs were positive for B. canis, H. canis, E. canis, and A. platys, respectively. Moreover, coinfection was found in 16.33% (8/49) of dogs.

Conclusion:

This study is the first report to demonstrate the molecular prevalence of blood parasites in domestic dogs in Buriram Province. The results indicated that the PCR method exhibited much higher sensitivity and reliability for blood parasites diagnosis in dogs. Therefore, our data support serious concern regarding the diagnostic technique used in routine blood testing and also provide prevalence data for the management and control of blood parasites in this area.

Hepatozoon canis in three imported dogs: a new tickborne disease reaching the United Kingdom

An increasing number of non-endemic vectorborne pathogens have been described in dogs imported to the UK in the past two decades. Recently, an outbreak of canine babesiosis in south-east England has raised veterinary awareness with regard to the impact of such diseases on the UK canine population. Canine hepatozoonosis, caused by Hepatozoon canis and transmitted by the ingestion of Rhipicephalus sanguineus ticks, is widespread in the Mediterranean basin. Herein we describe the first three molecularly confirmed clinical cases of canine hepatozoonosis in dogs imported into the UK. Veterinarians in the UK should be aware of H canis as a potential infection in imported dogs, especially in the face of the expanding distribution of R sanguineus ticks in Europe.

Does co-infection with vector-borne pathogens play a role in clinical canine leishmaniosis?

BACKGROUND

The severity of canine leishmaniosis (CanL) due to Leishmania infantum might be affected by other vector-borne organisms that mimic its clinical signs and clinicopathological abnormalities. The aim of this study was to determine co-infections with other vector-borne pathogens based on serological and molecular techniques in dogs with clinical leishmaniosis living in Spain and to associate them with clinical signs and clinicopathological abnormalities as well as disease severity.

METHODS

Sixty-one dogs with clinical leishmaniosis and 16 apparently healthy dogs were tested for Rickettsia conorii, Ehrlichia canis, Anaplasma phagocytophilum and Bartonella henselae antigens by the immunofluorescence antibody test (IFAT) and for E. canis, Anaplasma spp., Hepatozoon spp., Babesia spp. and filarioid DNA by polymerase chain reaction (PCR).

RESULTS

Among the dogs examined by IFAT, the seroprevalences were: 69% for R. conorii, 57% for E. canis, 44% for A. phagocytophilum and 37% for B. henselae; while the prevalences found by PCR were: 8% for Ehrlichia/Anaplasma, 3% for Anaplasma platys and 1% for H. canis. No other pathogen DNA was detected. Statistical association was found between dogs with clinical leishmaniosis and seroreactivity to R. conorii antigen (Fisher's exact test: P = 0.025, OR = 4.1, 95% CI = 1-17) and A. phagocytophilum antigen (Fisher's exact test: P = 0.002, OR = 14.3, 95% CI = 2-626) and being positive to more than one serological or molecular tests (co-infections) (Mann-Whitney test: U = 243, Z = -2.6, n ₁  = 14, n ₂  = 61, P = 0.01) when compared with healthy dogs. Interestingly, a statistical association was found between the presence of R. conorii, E. canis, A. phagocytophilum and B. henselae antibodies in sick dogs and some clinicopathological abnormalities such as albumin and albumin/globulin ratio decrease and increase in serum globulins. Furthermore, seroreactivity with A. phagocytophilum antigens was statistically associated with CanL clinical stages III and IV.

CONCLUSIONS

This study demonstrates that dogs with clinical leishmaniosis from Catalonia (Spain) have a higher rate of co-infections with other vector-borne pathogens when compared with healthy controls. Furthermore, positivity to some vector-borne pathogens was associated with more marked clinicopathological abnormalities as well as disease severity with CanL.

First description of the pathogenicity of Babesia vogeli in experimentally infected dogs

Babesiosis is a tick-borne disease that occurs worldwide with the most recognized Babesia species that infect dogs being Babesia canis, B. vogeli, B. rossi and B. gibsoni. While B. vogeli is reported in dogs worldwide, clinical and laboratory data on infections is based on reports of naturally infected dogs. To provide reliable data on the clinical and laboratory abnormalities associated with acute and more chronic infections in healthy dogs free of other tick-borne diseases, we experimentally infected dogs with a Chinese strain of B. vogeli. All of the six infected Beagles, three of which were splenectomized, became infected with B. vogeli detected in blood smears taken the day following infection and the organism detected by FRET-qPCRs in most blood samples (77/86; 90%) collected about every 4 days until the end of the experiment on day 95. All the infected dogs showed fever, partial anorexia and malaise that was more severe in the splenectomized dogs that did not gain weight for three weeks in the period after initial infection. Regenerative anemia, thrombocytopenia and decreased white blood cell counts were seen in all dogs but were more severe in the splenectomized dogs, of which two had life threatening infections and had to be removed from the study for treatment. Following re-infection on day 66, none of the dogs showed clinical signs and copy numbers did not change significantly although all the dogs were negative by FRET-qPCR on at least some of the subsequent sampling days. Laboratory values in the non-splenectomized dogs were relatively unchanged while in the splenectomized dog there was a temporary small increase in the platelet and white blood cell counts and a temporary slight worsening of the anemia. In summary, our study shows dogs experimentally infected with a B. vogeli strain from China develop only mild clinical signs that are followed by asymptomatic infections that can last for least 95 days. In splenectomized dogs, however, severe life threatening signs may develop.