Prevalence and molecular characterization of piroplasmids in domestic dogs from Paraguay

Phylogenetic inferences based on distinct molecular markers reveals a novel Babesia (Babesia pantanalensis nov. sp.) and a Hepatozoon americanum-related genotype in crab-eating foxes (Cerdocyon thous)

Piroplasmids and Hepatozoon spp. Are apicomplexan protozoa that may cause disease in several canid species. The present study aimed to expand the knowledge on the diversity of piroplasmids and Hepatozoon in crab-eating foxes (Cerdocyon thous; n = 12) sampled in the Pantanal of Mato Grosso do Sul State, central-western Brazil. PCR assays based on the 18S rRNA were used as screening. Three (25%) and 11 (91.7%) were positive for piroplasmids and Hepatozoon spp., respectively. Co-infection was found in three C. thous. Phylogenetic analyses based on the near-complete 18S rRNA, cox-1 and hsp70 genes evidenced the occurrence of a novel of Babesia spp. (namely Babesia pantanalensis nov. sp.) closely related to Rangelia vitalii and Babesia sp. 'Coco'. This finding was supported by the genetic divergence analysis which showed (i) high divergence, ranging from 4.17 to 5.62% for 18 S rRNA, 6.16% for hps70 and 4.91-9.25% for cox-1 and (ii) the genotype network (which displayed sequences separated from the previously described Piroplasmida species by median vectors and several mutational events). Also, phylogenetic analysis based on the 18S rRNA gene of Hepatozoon spp. positioned the sequences obtained herein in a clade phylogenetically related to Hepatozoon sp. 'Curupira 2', Hepatozoon sp. detected in domestic and wild canids from Uruguay and Hepatozoon americanum. The present study described Babesia pantanalensis nov sp. and Hepatozoon closely related to H. americanum in crab-eating foxes from Brazil. Moreover, the coinfection by piroplasmids and Hepatozoon sp. for the first time in crab-eating foxes strongly suggesting that this wild canid species potentially acts as a bio-accumulate of hemoprotozoan in wild environment.

Molecular survey of Piroplasmida, Hepatozoon spp. and Anaplasmataceae in anemic and thrombocytopenic dogs from Uruguay

Canine tick-borne diseases, such as babesiosis, rangeliosis, hepatozoonosis, anaplasmosis and ehrlichiosis, are of veterinarian relevance, causing mild or severe clinical cases that can lead to the death of the dog. The aim of this study was detecting tick-borne protozoan and rickettsial infections in dogs with anemia and/or thrombocytopenia in Uruguay. A total of 803 domestic dogs were evaluated, and 10% were found positive (detected by PCR) at least for one hemoparasite. Sequence analysis confirmed the presence of four hemoprotozoan species: Rangelia vitalii, Babesia vogeli, Hepatozoon canis and Hepatozoon americanum, and the rickettsial Anaplasma platys. The most detected hemoparasite was R. vitalii, followed by H. canis and A. platys. This is the first report of B. vogeli in Uruguay and the second report of H. americanum in dogs from South America. The results highlight the importance for veterinarians to include hemoparasitic diseases in their differential diagnosis of agents causing anemia and thrombocytopenia.

Piroplasmid Infections Among Domestic Dogs in the Mountain City of Rio de Janeiro, Brazil

PURPOSE

The aim of the present study was to analyze the frequency of the piroplasmids in blood from dogs and ticks recovered from these animals in Teresópolis city, located in the mountain region of Rio de Janeiro state, Brazil. In addition to the clinical and hematological profile.

METHODS

A total of 400 dogs attended in a veterinary clinic in this city between 2020 and 2021 were included. The blood was collected from the dogs, along with ticks and information on these dogs was obtained through a questionnaire applied to the owners. Thin-smear analyses and complete blood counts were performed. All forms characteristic of piroplasmids were measured and classified morphologically. The blood was also subjected to PCR assays based on the genes 18S rRNA and hsp70. In addition, the ixodid ticks were classified morphologically and subjected to PCR for piroplasmids research. The amplified products were sent for gene sequencing.

RESULTS

Piroplasmids were detected in 2.3% of the dogs. The variables statistically associated with infections in these animals were hemorrhage/bleeding, jaundice, anisocytosis, activated monocytes and macroplatelets (p ≤ 0.05). Piriform, ring-shaped, oval and aberrant structures were viewed in erythrocytes, neutrophils and monocytes, with lengths greater than and less than 2.5 µm. The nine positive samples from these dogs were characterized as due to Rangelia vitalii. However, one sequence from B. vogeli was detected in a single adult specimen of R. sanguineus.

CONCLUSION

Although circulation of two species of piroplasmids potentially infective for domestic dogs has been observed in the mountain city of Rio de Janeiro, infection due to R. vitalii was mostly seen in the dogs of the present study.

Bovine Piroplasma Populations in the Philippines Characterized Using Targeted Amplicon Deep Sequencing

Molecular assays and capillary electrophoresis sequencing have been used to identify parasites in livestock. The low sample capacity, which increases labor and processing time, is one drawback. Targeted amplicon sequencing (Ampliseq) uses the fast and large sample capacity platform to identify parasites in the target host, overcoming this limitation. DNA was extracted from 162 whole blood samples collected from cattle in three provinces in the Philippines. Using Illumina's Miseq platform, the V4 hypervariable region of the piroplasma 18S rRNA gene was amplified and sequenced. The AMPtk pipeline was used to obtain distinct amplicon sequence variants (ASVs) and the NCBI BLAST non-redundant database was used to assign taxonomy. In total, 95 (58.64%) samples were positive for piroplasma. Using the AMPTk pipeline, 2179 ASVs were obtained. A total of 79 distinct ASVs were obtained after clustering and filtering, which belonged to genera Babesia (n = 58), Theileria (n = 17), Hepatozoon (n = 2), and Sarcocystis (n = 2). The ASV top hits were composed of 10 species: Babesia bovis, B. bigemina, Theileria orientalis, Babesia sp., Hepatozoon canis, Sarcocystis cruzi, T. annulata, T. equi, T. mutans, and Theileria sp. Thung Song. The results generated in this study demonstrated the applicability of Ampliseq in detecting piroplasmid parasites infecting cattle in the Philippines.

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.

Canine piroplasmids: Molecular detection and laboratory characterization in dogs from Brasilia, Brazil, with the first molecular evidence of dog exposure to a novel opossum-associated Babesia sp

Canine piroplasmid infections can be caused by Babesia spp., Theileria spp. and Rangelia vitalii. In Brazil, canine babesiosis caused by Babesia vogeli is endemic and reported throughout the country. On the other hand, Rangeliosis caused by R. vitalii has only been described so far in the South and Southeast regions. Despite that, studies analyzing the laboratory and molecular characterization of these hemoprotozoa are still scarce. To investigate the occurrence, the laboratory features, the molecular characterization, and the diversity of piroplasmids from Midwestern Brazil, a survey was performed using blood samples obtained from 276 domestic dogs from Brasília, Federal District, Midwestern Brazil. A broad-range quantitative PCR (qPCR) targeting the mitochondrial large subunit ribosomal DNA (LSU4) was used to detect piroplasmid DNA. The overall molecular occurrence of piroplasmids was 11.2% (31/276), with 9.7% (27/276) of the sequences identified as Babesia vogeli (98-100% identity to B. vogeli isolate from the USA). Based on a partial 18S rRNA sequence pairwise alignment (-250 bp), 1.4% (4/276) of the sequences showed only 76.8% identity with B. vogeli but 100% identity with opossum-associated Babesia sp. (MW290046-53). These findings suggest the exposure of dogs from Brazil to a recently described Babesia sp. isolated from white-eared opossum. None of the analyzed dogs was positive for Theileria spp. or R. vitalii. Subsequently, all positive sequences were submitted to three additional PCR assays based on the 18S rRNA, cox-1, and cytb genes, aiming at performing a haplotype network analysis. Haplotype network using cox-1 sequences showed the presence of six different haplotypes of B. vogeli; one of them was shared with isolates from Brazil, the USA, and India. When including animals co-infected with other vector-borne diseases, piroplasmid-positive dogs had 2.3 times higher chance of having thrombocytopenia than the negative ones. The molecular results demonstrated that the compared Babesia vogeli sequences showed a low variability as well as evidence of exposure to a putative novel opossum-associated Babesia sp. in dogs from Midwestern Brazil.

PCR detection of Theileria equi and Babesia caballi in apparently healthy horses in Paraguay

Equine piroplasmosis (EP) is a tick-borne disease caused by Theileria equi and Babesia caballi in equids, including horses. EP has a global distribution and often leads to a significant socioeconomic impact on the equine industry. Infected animals remain as carriers and become a source of infection for tick vectors, thereby posing an immense challenge in the disease management. Therefore, detection of these carriers is crucial to assess the risk of transmission and to implement appropriate control measures in endemic countries. Paraguay is a tropical country where various tick-borne diseases are common among livestock; however, the status of EP remains unknown in this country. Because the tick vectors capable of transmitting T. equi and B. caballi are endemic in Paraguay, we hypothesised that Paraguayan horses are infected with these parasite species. To test our hypothesis, we prepared blood DNA samples from a total of 545 apparently healthy horses in 16 of the 17 departments of Paraguay and analysed them with specific PCR assays to detect T. equi and B. caballi. The PCR results showed that 178 (32.7%) and 8 (1.5%) of the horses were infected with T. equi and B. caballi, respectively. Among the infected horses, two (0.4%) were infected with both parasite species. Our analyses further indicated that the positive rates of T. equi infection did not differ between horse breeds, males and females, or age groups. We also found that haematological parameters were the same between the non-infected animals and animals with single infections. By contrast, the two horses co-infected with T. equi and B. caballi had haemoglobin and haematocrit values lower than the normal ranges. In conclusion, the present study demonstrated that Paraguayan horses are infected with T. equi and B. caballi and that the rate of T. equi infection is higher than that of B. caballi. Our findings highlight the need to add EP to the list of differential diagnoses when anaemic horses are presented to equine clinics in Paraguay.

Arthropod-Borne Pathogens in Wild Canids

Wild canids, as well as other wild animal species, are largely exposed to bites by ticks and other hematophagous vectors where the features favoring their presence and spread are found in wooded and semi-wooded areas. Much of the information about arthropod-borne infections concerns domestic and companion animals, whereas data about these infections in wild canids are not exhaustive. The present study is a narrative review of the literature concerning vector-borne infections in wild canids, highlighting their role in the epidemiology of arthropod-borne bacteria and protozoa.

18S rRNA Gene-Based Piroplasmid PCR: An Assay for Rapid and Precise Molecular Screening of Theileria and Babesia Species in Animals

PURPOSE

The parasites of genera such as Babesia and Theileria are called piroplasmids due to the pear-shaped morphology of the multiplying parasite stages in the blood of the vertebrate host. Because of the enormous number of parasite species and the challenges of multiplex PCR, initial screening of samples using piroplasmid-specific PCR may be a more cost-effective and efficient technique to identify parasite species, especially during epidemiological studies. Accordingly, 18S rRNA PCR was standardized and optimized on common piroplasmids of different animals like cattle, buffaloes, sheep, goats, dogs, horses, and leopards.

METHODS

Bloods samples from 1250 animals were collected from different animals in Junagadh district of Gujarat, India. 18S rRNA PCR was standardized and optimized as a primary method for molecular screening of piroplasms in domestic and wild animals. The method was checked for its analytical sensitivity and specificity. Parasite species-specific PCR and sequencing was used to validate the test. Moreover, in-silico restriction enzyme (RE) analysis was also done to assess its applicability in PCR-RFLP.

RESULTS

Piroplasm infections were recorded in 63.3% of animals in Junagadh. The 18S rRNA PCR detected the piroplasmid DNA in as low as 39 picograms (pg) of whole blood genomic DNA isolated from microscopically Theileria positive blood samples and no reactivity was recorded from common but unrelated haemoparasites viz., Trypanosoma evansi, Hepatozoon spp., Anaplasma spp., and Ehrlichia canis was observed. The 18S rRNA PCR assay findings were confirmed by species-specific PCR and sequencing. Analysis of different sequences generated using 18S rRNA PCR revealed that the amplicon size of Babesia spp. is nearly 400 bp (393-408 bp) whereas Theileria spp. were more than 400 bp (418-424 bp). The percentage of sequence divergence among Babesia and Theileria spp. was 7.3-12.2% and 0.7-12.2%, respectively. In-silico restriction enzyme (RE) analysis reveals the presence of at least one site for a commercially available RE in 18S rRNA fragments of every parasite, which can differentiate it from its congeners.

CONCLUSIONS

The presented universal oligonucleotide-based PCR assay provides a highly sensitive, specific, cost-effective, and rapid diagnostic tool for the initial screening of piroplasmids infecting domestic and wild animals and is potentially helpful for large-scale epidemiological studies.

Theileria terrestris nov. sp.: A Novel Theileria in Lowland Tapirs (Tapirus terrestris) from Two Different Biomes in Brazil

The low-land tapir (Tapirus terrestris) is the largest wild terrestrial mammal found in Brazil. Although T. terrestris has been already reported as a host of hemoparasites, the occurrence and genetic identity of Piroplasmida agents in this species is still cloudy. Although it is reported that Theileria equi, an endemic equid-infective agent in Brazil, is occurring in lowland tapirs, these reports are probably misconceived diagnoses since they are solely based on small fragments of 18S rRNA that may not achieve accurate topologies on phylogenetic analyses. The present study aimed to detect and investigate the identity of Theileria spp. in tapirs from Pantanal and Cerrado biomes. Blood-DNA samples from tapirs were screened for a partial (~800 bp) 18S rRNA gene fragment from Piroplasmida and 64 (64/122; 52.46% CI: 43.66-61.11%) presented bands of expected size. Samples were submitted to different protocols for molecular characterization, including near-full length 18S rRNA gene (~1500 bp), and the ema-1 gene from T. equi. Eight sequences were obtained for extended fragments (1182-1473 bp) from the 18S rRNA gene. Moreover, three sequences from partial cox-1 and five from partial hsp70 gene were obtained. None of the samples presented amplifications for the ema-1 gene. Phylogenetic and distance analyses from the 18S rRNA sequences obtained demonstrated a clear separation from tapirs' Theileria spp. and T. equi. Phylogenetic analyses of cox-1 and hsp70 sequences obtained herein also showed a unique clade formed by tapir's Theileria spp. Theileria terrestris sp. nov. is positioned apart from all other Theileria species in 18S rRNA, cox-1, and hps70 phylogenetic analyses. This novel proposed species represents a new Piroplasmida clade, yet to be characterized regarding biological features, vectors involved in the transmission cycles, additional vertebrate hosts, and pathogenicity.

First report of canine rangeliosis in domestic dogs from different regions of Santa Catarina State, Brazil

Rangeliosis is the disease caused by Rangelia vitalii, a parasite reported in dogs from southeastern and southern Brazil, Uruguay, Paraguay, and Argentina. This protozoan is transmitted by the ixodid Amblyomma aureolatum, and infects erythrocytes, leukocytes, and vascular endothelial cells of the host. The common clinical signs, such as prostration, fever, anemia, thrombocytopenia, anorexia, weight loss, and dehydration, are also found in other infections, like canine babesiosis and ehrlichiosis. The similar clinical presentation with other diseases, as well as the indistinguishable morphology with intraerythrocytic Babesia canis, complicates the disease diagnostic. In the present study, blood samples from dogs presenting clinical signs compatible with hemoparasitosis were investigated for rangeliosis. The dogs were treated at veterinary clinics in the cities of Blumenau and Lages, in the State of Santa Catarina, Brazil. Blood samples from 17 dogs were analyzed by PCR. The samples were screened by a conventional piroplasma-PCR and the positives confirmed by a specific R. vitalii-qPCR. Two animals (2/17; 11.8%) were positive for R. vitalii, one from Blumenau and the other from Lages. Both animals presented unspecific signs of hemoparasitosis, such as apathy, anemia, and anorexia. The results indicate the necessity of molecular assays for the proper identification of the hemoparasite, and to investigate the real prevalence of rangeliosis in the State of Santa Catarina.

18S rRNA Gene-Based Piroplasmid PCR: An Assay for Rapid and Precise Molecular Screening of Theileria and Babesia Species in Animals

Purpose

The parasites of genera such as Babesia and Theileria are called piroplasmids due to the pear-shaped morphology of the multiplying parasite stages in the blood of the vertebrate host. Because of the enormous number of parasite species and the challenges of multiplex PCR, initial screening of samples using piroplasmid-specific PCR may be a more cost-effective and efficient technique to identify parasite species, especially during epidemiological studies. Accordingly, 18S rRNA PCR was standardized and optimized on common piroplasmids of different animals like cattle, buffaloes, sheep, goats, dogs, horses, and leopards.

Methods

Bloods samples from 1250 animals were collected from different animals in Junagadh district of Gujarat, India. 18S rRNA PCR was standardized and optimized as a primary method for molecular screening of piroplasms in domestic and wild animals. The method was checked for its analytical sensitivity and specificity. Parasite species-specific PCR and sequencing was used to validate the test. Moreover, in-silico restriction enzyme (RE) analysis was also done to assess its applicability in PCR–RFLP.

Results

Piroplasm infections were recorded in 63.3% of animals in Junagadh. The 18S rRNA PCR detected the piroplasmid DNA in as low as 39 picograms (pg) of whole blood genomic DNA isolated from microscopically Theileria positive blood samples and no reactivity was recorded from common but unrelated haemoparasites viz., Trypanosoma evansi, Hepatozoon spp., Anaplasma spp., and Ehrlichia canis was observed. The 18S rRNA PCR assay findings were confirmed by species-specific PCR and sequencing. Analysis of different sequences generated using 18S rRNA PCR revealed that the amplicon size of Babesia spp. is nearly 400 bp (393–408 bp) whereas Theileria spp. were more than 400 bp (418–424 bp). The percentage of sequence divergence among Babesia and Theileria spp. was 7.3–12.2% and 0.7–12.2%, respectively. In-silico restriction enzyme (RE) analysis reveals the presence of at least one site for a commercially available RE in 18S rRNA fragments of every parasite, which can differentiate it from its congeners.

Conclusions

The presented universal oligonucleotide-based PCR assay provides a highly sensitive, specific, cost-effective, and rapid diagnostic tool for the initial screening of piroplasmids infecting domestic and wild animals and is potentially helpful for large-scale epidemiological studies.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11686-022-00625-2.

Seroprevalence and prevalence of Babesia vogeli in clinically healthy dogs and their ticks in Costa Rica

Canine babesiosis is a disease caused by a parasite of the genus Babesia which destroys red blood cells. Previous studies have shown the presence of Babesia vogeli in rural areas in Costa Rica using molecular techniques. The objective of the present study was to determine the seroprevalence and prevalence of B. vogeli in clinically healthy dogs and their ticks at the national level, both within and outside the Central Valley. Blood samples and ticks from 482 dogs were collected between June 2011 and May 2014, and analyzed by immunofluorescence assay (IFA) and real-time polymerase chain reaction (qPCR); two protocols of endpoint PCR and sequencing were used to confirm qPCR-positive samples. Seroprevalence of canine babesiosis of 5.3% (24/453) was determined at the national level, specifically 2.0% (5/253) within and 9.5% (19/200) outside the Central Valley, respectively. Real-time PCR determined a global prevalence of B. vogeli of 31.3% (125/400): 21.4% (47/220) within the Central Valley and 43.3% (78/180) outside the Central Valley. The endpoint PCR amplified only 10 of the 125 blood samples identified as positive in qPCR. One sample amplified by endpoint PCR was sequenced and identified as B. vogeli. Twelve canines were identified with past infections, seven canines with active infection, and 111 canines with early infection. Two species of ticks were found with B. vogeli: Rhipicephalus sanguineus sensu lato (n = 40) and Amblyomma ovale (n = 1). The prevalence of canine babesiosis at the national level, both within and outside the Central Valley, is reported here for the first time, determining the presence of the piroplasmid throughout the country, with a higher circulation of the agent outside the Central Valley. Only one species, B. vogeli, was detected in the blood of dogs and their ticks. Therefore, veterinarians should consider using qPCR to determine the presence of the parasite in blood donors and before starting treatment of vector-borne disease in dogs.

Molecular detection and phylogenetic characterization of Theileria equi in horses (Equus caballus) from a peri-urban area of Argentina

To investigate the presence of Theileria equi in an endemic area of equine piroplasmosis 42 horses (Equus caballus) from Corrientes City, Argentina were sampled. Eighty-one percent (34 blood samples) of the analyzed horses were tested positive to the presence of piroplasmid 18S rDNA. All these samples could be identified as T. equi by amplifying the specific EMA-1 (merozoite antigen 1) gene of this species. Phylogenetic analysis of an obtained 18S rDNA complete sequence from one strain resulted in the identification of this sample as T. equi sensu stricto (genotype A). This study presents the first molecular detection and characterization of T. equi by the complete 18S rDNA sequence in Argentina. Based on these results further studies should be carried out to investigate the distribution and heterogeneity of presented genotypes of T. equi in Argentina, which is essential for the diagnosis, prevention and treatment of equine piroplasmosis.

A survey on equine tick-borne diseases: The molecular detection of Babesia ovis DNA in Turkish racehorses

Common vector-borne diseases of horses include equine piroplasmosis (EP) caused by Babesia caballi and Theileria equi, and equine granulocytic anaplasmosis (EGA) caused by Anaplasma phagocytophilum. Equine piroplasmosis leads to severe health issues in horses and restrictions on the movement of horses internationally. Anaplasma phagocytophilum causes an acute febrile illness in horses and is also of zoonotic importance. In the present study, blood samples were collected from 152 Turkish racehorses from three different provinces (İzmir, Gaziantep, and Konya) of Turkey to investigate the prevalence of EP and EGA. Standard and nested polymerase chain reactions were performed to identify equine piroplasms and A. phagocytophilum, respectively. PCR primers targeting Babesia spp. 18S rRNA, B. caballi BC48, T. equi EMA-1, and A. phagocytophilum 16S rRNA genes were used for molecular diagnosis. Following the cloning and subsequent sequencing of PCR-positive samples, a total of 15 (9.9%) horses were found to be infected with at least one pathogen. Theileria equi and A. phagocytophilum were found in 3.3% (5/152) and 6.6% (10/152) of the samples, respectively. Although B. caballi specimens were not detected in any of the samples, a positive signal was detected for the Babesia genus-specific 18S rRNA PCR. Subsequent sequencing of this signal revealed 100% identity to Babesia ovis. This is the first detection of B. ovis DNA in racehorses in Turkey to the best of our knowledge. Additionally, this study also reports the first molecular identification of A. phagocytophilum in Turkish racehorses. Based on this report, it is recommended that future epidemiological studies on horses also take B. ovis, a parasite usually found in sheep, into consideration and that further detailed studies be conducted to unravel the transmission pathways and potential clinical effects of B. ovis in horses.

Spatial distribution and molecular epidemiology of Babesia vogeli in household dogs from municipalities with different altitude gradients in the state of Rio de Janeiro, Brazil

We performed a cross-sectional epidemiological study with 456 household dogs from urban and rural areas in two different regions situated at different altitudes in the state of Rio de Janeiro. The PCR technique using 18S rRNA as target revealed prevalence of 7.9% of dogs positive for piroplasmids. These samples were sequenced, and all the sequences were 99.9% to 100% similar to Babesia vogeli sequences from other countries. The spatial distribution of positive cases was analysed using kernel interpolation in the QGIS software, and the spatial correlation indicators among positive dogs, altitude, and presence of ticks were obtained by calculating the local Moran index using the GeoDa software. The spatial correlation between positive cases and altitude was clear based on both visual and statistical observations. Logistic regression applying the Wald method with a cutoff point of 0.1 revealed that dogs from a region with altitude <600 m had a 2.29-fold chance of B. vogeli infection (OR = 2.29; p-value = 0.04; CI: 1.03-5.07), while the rainy season was 2.45 times more associated with B. vogeli infection (OR = 2.45; p-value = 0.01; CI: 1.20-5.01), and dogs infested with Rhipicephalus sanguineus sensu lato had a 2.47 times higher chance of being infected (OR = 2.47; p-value = 0.02; CI: 1.13-5.38). Entropy analysis of the alignment between B. vogeli 18S rRNA (> 1.600 bp) sequences revealed that the most variable region corresponds to the hypervariable V4 region. Genetic homogeneity was observed among the B. vogeli 18S rRNA sequences, with distance values ranging from 0 to 0.007 and a mean value of 0.001. The evolutionary distance (0.003) was greater between the sequences from the municipalities of Barra do Pirai (low altitude) and Teresopolis (high altitude). This study expands the molecular epidemiologic knowledge of B. vogeli and shows points of variability in the B. vogeli 18S rRNA. The results indicate the potential use of spatial analysis tools to improve screening for positive cases, enabling more in-depth studies to strengthen understanding of tick infection prevention in dogs.

Rangelia vitalii in free-living crab-eating foxes (Cerdocyon thous) in Uruguay

Rangelia vitalii is a protozoan parasite that causes a hemorrhagic and hemolytic disease in dogs known as rangeliosis. Current reports of the disease are concentrated in the southern and southeastern regions of Brazil, as well as in Uruguay, Argentina, and Paraguay, and mainly concern domestic dogs. South American wild canids, such as the crab-eating fox (Cerdocyon thous), the pampas fox (Lycalopex gymnocercus), and the maned wolf (Chrysocyon brachyurus) may also be affected, although existing reports are restricted to Brazil. The present study aimed to detect R. vitalii parasitism in the Uruguayan wild fox population. DNA extracted from the blood and/or spleen samples of road-killed C. thous and L. gymnocercus found in northern Uruguay were subjected to polymerase chain reaction (PCR) to amplify a 551-bp fragment of the Rangelia 18S rRNA gene. A total of 62 wild canids, including 38 C. thous and 24L. gymnocercus, were analyzed. Five crab-eating fox samples (13.2%) were positive for R. vitalii, with 99.5-100% identity between the sequences. All samples from pampas fox tested negative for R. vitalii. When compared with the R. vitalii sequences available in GenBank, a similarity of 98.9-100% was revealed. Molecular analysis results suggest that R. vitalii is circulating in the crab-eating fox population in Uruguay; however, its veterinary relevance for these foxes remains unknown.

Rangelia vitalii molecular and histological quantification in tissues comparing crab-eating foxes (Cerdocyon thous) and domestic dogs

Rangeliosis is a condition transmitted by the tick Amblyomma aureolatum and caused by the protozoan parasite Rangelia vitalii in canids. In domestic dogs, the disease causes a severe hemolytic disease, while in wild canids the piroplasm is often detected without any clinical abnormality. This study aimed to detect and quantify the number of copies of the R. vitalii Hsp70 gene (indirect parasite burden) in several organs of domestic and South American wild canids (Cerdocyon thous and Lycalopex gymnocercus) to elucidate distinct clinical presentations of rangeliosis in these species. A total of seven domestic dogs that died due to rangeliosis and 38 wild foxes were initially included, with all dogs presenting histological and molecular features of rangeliosis, while eight C. thous were positive at the molecular analysis for R. vitalii. Fragments of 22 organs collected from domestic (n = 7) and wild foxes (n = 8) were employed for histological and molecular quantification using real-time polymerase chain reaction aiming at the Hsp70 gene. Histologically, parasitophorous vacuoles were constantly detected in the dogs, while these were detected only in two C. thous. Parasitic burden was significantly higher in the digestive, cardiorespiratory, endocrine, genitourinary, and skeletal-muscle systems of domestic dogs when compared to wild foxes. In the hematopoietic system of wild canids, some organs, such as the lymph nodes and tonsils, presented significantly lower amounts of R. vitalii, while other organs (spleen, bone marrow, and blood) had results similar to those of domestic dogs. Additionally, the central nervous system of both domestic and wild canids presented a similar quantity of R. vitalii. The etiological agent is possibly maintained through an asexual reproductive process (merogony) in both domestic and wild species. Nonetheless, a limited or short-duration schizogony phase occurs in C. thous, which would designate this species as a possible reservoir host for the agent. Dogs, in contrast, would most likely act as accidental hosts, presenting a severe and more pathogenic schizogony phase, resulting in characteristic clinical and pathological rangeliosis.

Babesia bicornis, Theileria bicornis and Theileria equi in metapopulations of two black rhinoceros (Diceros bicornis) subspecies in South Africa and their potential impact on conservation

The two black rhinoceros subspecies (Diceros bicornis bicornis and D. b. minor) in South African conservation areas are managed as separate metapopulations. Since infection with Babesia bicornis can be fatal in black rhinoceroses, occurrence of this and other piroplasms in the two metapopulations was determined to assess possible risk. Blood specimens were collected from 156 black rhinoceroses: 80 from D. b. bicornis and 76 from D. b. minor. DNA was extracted; the V4 hypervariable region of the parasite 18S rRNA gene was amplified and subjected to the Reverse Line Blot (RLB) hybridization assay. There was a significant difference in occurrence of piroplasms: 18/80 (23%) in D. b. bicornis and 39/76 (51%) in D. b. minor. Theileria bicornis occurred in significantly more of the D. b. minor population (36/76; 47%) than the D. b. bicornis population (1/80; 1%); with B. bicornis the difference was not significant: D. b. bicornis 5/80 (6%) and D. b. minor 9/76 (11%). Three individuals were infected with Theileria equi. Results were confirmed using molecular characterization of the near full-length parasite 18S rRNA gene of 13 selected specimens. We identified four (Tb1, Tb2, Tb3 and Tb4) 18S rDNA sequence types for T. bicornis, two for B. bicornis (Bb1 and Bb2) and one for T. equi (Teq1). We furthermore identified T. bicornis haplotypes H1, H3 and H4 in 10 rhinoceroses; H3 was the most common haplotype identified. Rhinoceroses inhabiting more arid areas are apparently free of T. bicornis and B. bicornis, probably due to the absence or scarcity of vectors. When individuals are relocated for metapopulation management purposes, appropriate prophylactic action should be taken to minimise the risk of babesiosis, which could be fatal.

Twenty Years of Equine Piroplasmosis Research: Global Distribution, Molecular Diagnosis, and Phylogeny

Equine piroplasmosis (EP), caused by the hemoparasites Theileria equi, Theileria haneyi, and Babesia caballi, is an important tick-borne disease of equines that is prevalent in most parts of the world. Infection may affect animal welfare and has economic impacts related to limitations in horse transport between endemic and non-endemic regions, reduced performance of sport horses and treatment costs. Here, we analyzed the epidemiological, serological, and molecular diagnostic data published in the last 20 years, and all DNA sequences submitted to GenBank database, to describe the current global prevalence of these parasites. We demonstrate that EP is endemic in most parts of the world, and that it is spreading into more temperate climates. We emphasize the importance of using DNA sequencing and genotyping to monitor the spread of parasites, and point to the necessity of further studies to improve genotypic characterization of newly recognized parasite species and strains, and their linkage to virulence.

First detection and molecular identification of Babesia sp. from the giant panda, Ailuropoda melanoleuca, in China

BACKGROUND

Parasitic infections are among the important causes of death of giant pandas (Ailuropoda melanoleuca) that hamper their survival in the wild. There are about 35 species of parasites which have been identified in giant pandas, but no information is currently available regarding the infection of Babesia in giant pandas. Babesia spp. are common intraerythrocytic parasite in wildlife, transmitted by ixodid ticks, which cause babesiosis. Clinical signs of babesiosis include fever, hemolysis, anemia, jaundice and death.

METHODS

A species of Babesia was detected in the blood of a giant panda based on morphology and PCR amplification of the 18S rRNA gene. The phylogenetic relationship of Babesia sp. infecting giant panda was assessed by gene sequence alignment and phylogenetic analysis.

RESULTS

Our analysis revealed that the Babesia isolate detected was most similar to an unidentified species of Babesia identified in black bears (Ursus thibetanus japonicus) from Japan (Babesia sp. Iwate, AB586027.1) with a 99.56% sequence similarity, followed by Babesia sp. EBB (AB566229.1, 99.50%) and Babesia sp. Akita (AB566229.1, 99.07%).

CONCLUSIONS

To our knowledge, this is the first report of Babesia detected in the giant panda. The results indicate that this Babesia sp. may be a novel species, currently named Babesia sp. strain EBP01.

Use of molecular tools for the diagnosis of rangeliosis by Rangelia vitalii in Argentina: A case report

Vector-borne pathogens are responsible for serious emerging diseases and Rangelia vitalii, the etiologic agent of canine rangeliosis, is one of the most pathogenic tick-borne pathogens for dogs in South America. This protozoan is transmitted by the Amblyomma aureolatum tick bite and the clinical features associated to the disease are fever, hemolytic anemia, jaundice, hepatosplenomegaly and bleeding from natural orifices, mainly from the ear egde. The reports of canine rangeliosis in Argentina are scarce. In the present study we report the detection of Rangelia vitalii in a naturally infected dog from Gualeguay, Entre Ríos, Argentina with history of tick infestation and clinical signs compatible with rangeliosis. An initial blood sample was positive to piroplasmids by blood smear examination and the molecular amplification of a fragment of the 18SrRNA gene. Sequencing of the fragment confirmed the pathogen identity. After treatment with imidocarb dipropionate, the clinical signs remitted and the blood smear tested negative.

Canine babesiosis: A literature review of prevalence, distribution, and diagnosis in Latin America and the Caribbean

Canine babesiosis is a tick-borne disease with worldwide distribution and global significance. Traditionally, canine babesiosis was caused by B. canis (large Babesia) and B. gibsoni (small Babesia) based on cytological examination of stained blood smears. Currently, molecular techniques have demonstrated that several Babesia species infect dogs: B. canis, B. vogeli, and B. rossi (large forms) and B. gibsoni, B. conradae, and B. vulpes (small forms). In this study, we compiled and reviewed currently available data on Babesia infections in dogs in Latin America and the Caribbean, as well as on distribution of Babesia species with respect to prevalence, geographic location, and methods of detection. Forty-three studies on canine babesiosis published from 2005 to 2019 were included. The publications retrieved reported three species of Babesia (B. vogeli, B. gibsoni, and B. caballi) based on molecular confirmation of the species. Babesia vogeli was reported in Mexico, Costa Rica, Granada, Haiti, Nicaragua, Saint Kitts and Nevis, Trinidad and Tobago, Argentina, Brazil, Chile, Colombia, Paraguay, Peru, and Venezuela. In contrast, B. gibsoni was recorded in Costa Rica, Nicaragua, Saint Kitts and Nevis, and Brazil. Babesia caballi was found in a dog from Brazil. Babesia prevalence in dogs varied considerably based on parasite species and geographic location, with values close zero to 26.2%. Besides molecular techniques such as PCR, studies included examination of blood smears by microscopy and/or serologic tests. Few countries in the region, e.g., Brazil and Costa Rica, possess profound data availability, whereas the majority of them have scarce information or no data. A deeper understanding of the ecology and epidemiology of Babesia spp. in dogs is needed for the region.

A Review on Equine Piroplasmosis: Epidemiology, Vector Ecology, Risk Factors, Host Immunity, Diagnosis and Control

Equine Piroplasmosis (EP) is a tick-borne disease caused by apicomplexan protozoan parasites, Babesia caballi and Theileria equi. The disease is responsible for serious economic losses to the equine industry. It principally affects donkeys, horses, mules, and zebra but DNA of the parasites has also been detected in dogs and camels raising doubt about their host specificity. The disease is endemic in tropical and temperate regions of the world where the competent tick vectors are prevalent. Infected equids remain carrier for life with T. equi infection, whilst, infection with B. caballi is cleared within a few years. This review focuses on all aspects of the disease from the historical overview, biology of the parasite, epidemiology of the disease (specifically highlighting other non-equine hosts, such as dogs and camels), vector, clinical manifestations, risk factors, immunology, genetic diversity, diagnosis, treatment, and prevention.

A review on the occurrence of companion vector-borne diseases in pet animals in Latin America

Companion vector-borne diseases (CVBDs) are an important threat for pet life, but may also have an impact on human health, due to their often zoonotic character. The importance and awareness of CVBDs continuously increased during the last years. However, information on their occurrence is often limited in several parts of the world, which are often especially affected. Latin America (LATAM), a region with large biodiversity, is one of these regions, where information on CVBDs for pet owners, veterinarians, medical doctors and health workers is often obsolete, limited or non-existent. In the present review, a comprehensive literature search for CVBDs in companion animals (dogs and cats) was performed for several countries in Central America (Belize, Caribbean Islands, Costa Rica, Cuba, Dominican Republic, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Puerto Rico) as well as in South America (Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, French Guiana, Guyana (British Guyana), Paraguay, Peru, Suriname, Uruguay, Venezuela) regarding the occurrence of the following parasitic and bacterial diseases: babesiosis, heartworm disease, subcutaneous dirofilariosis, hepatozoonosis, leishmaniosis, trypanosomosis, anaplasmosis, bartonellosis, borreliosis, ehrlichiosis, mycoplasmosis and rickettsiosis. An overview on the specific diseases, followed by a short summary on their occurrence per country is given. Additionally, a tabular listing on positive or non-reported occurrence is presented. None of the countries is completely free from CVBDs. The data presented in the review confirm a wide distribution of the CVBDs in focus in LATAM. This wide occurrence and the fact that most of the CVBDs can have a quite severe clinical outcome and their diagnostic as well as therapeutic options in the region are often difficult to access and to afford, demands a strong call for the prevention of pathogen transmission by the use of ectoparasiticidal and anti-feeding products as well as by performing behavioural changes.