Detection and Prevalence of Babesia spp. in American Black Bears (Ursus americanus) from Eastern and Western North Carolina, USA

Survey for Babesia spp. in wildlife in the eastern United States

Babesia is a diverse genus of piroplasms that parasitize the red blood cells of a wide variety of mammals and avian species, including humans. There is a lack of knowledge on the Babesia species of carnivores and mesomammals in the eastern United States and the potential impacts of these species on the health of humans and domestic animals. We surveyed 786 wild mammals in the eastern United States by testing blood, spleen, and heart samples with PCR targeting the 18S rRNA region of apicomplexan parasites. We also performed PCR targeting the cytochrome c oxidase subunit 1 (cox1) region of each unique clade identified with 18S rRNA sequencing. We found a high positivity of Babesia spp. infection in raccoons (Procyon lotor), foxes (Vulpes vulpes and Urocyon cinereoargenteus), and striped skunks (Mephitis mephitis), and low positivity in Virginia opossums (Didelphis virginiana). No Babesia infections were detected in coyotes (Canis latrans), black bears (Ursus americanus), groundhogs (Marmota monax), muskrats (Ondatra zibethicus), or mink (Neovison vison). Skunks carried a diverse number of strains including a potential novel species of Babesia related to B. gibsoni, a strain closely related to a B. microti-like species known to cause disease in river otters, as well as a separate B. microti-like strain. Raccoons primarily carried B. microti-like strains, though there was a high diversity of sequences including Babesia lotori, Babesia sensu stricto MA230, and Babesia sp. 'Coco.' Foxes exclusively carried B. vulpes. In addition to Babesia spp., a high positivity of Hepatozoon spp. infection was found in mink, while low positivity was found in raccoons and muskrats. Wildlife in the eastern United States carry a diverse range of Babesia species including several novel strains of unknown clinical significance.

Description and molecular characterisation of Babesia ailuropodae n. sp., a new piroplasmid species infecting giant pandas

BACKGROUND

Babesia spp. are protozoan parasites that infect the red blood cells of domesticated animals, wildlife and humans. A few cases of giant pandas (a flagship species in terms of wildlife conservation) infected with a putative novel Babesia sp. have been reported. However, comprehensive research on the morphological and molecular taxonomic classification of this novel Babesia sp. is still lacking. This study was designed to close this gap and formally describe this new Babesia sp. infecting giant pandas.

METHODS

Detailed morphological, molecular and phylogenetic analyses were conducted to characterise this Babesia sp. and to assess its systematic relationships with other Babesia spp. Blood samples from giant pandas infected with Babesia were subjected to microscopic examination. The 18S ribosomal RNA (18S rRNA), cytochrome b (cytb) and mitochondrial genome (mitogenome) of the new Babesia sp. were amplified, sequenced and assembled using DNA purified from blood samples taken from infected giant pandas. Based on the newly generated 18S rRNA, cytb and mitogenome sequences, phylogenetic trees were constructed.

RESULTS

Morphologically, the Babesia sp. from giant pandas exhibited various forms, including round to oval ring-shaped morphologies, resembling those found in other small canine Babesia spp. and displaying typical tetrads. Phylogenetic analyses with the 18S rRNA, cytb and mitogenome sequences revealed that the new Babesia sp. forms a monophyletic group, with a close phylogenetic relationship with the Babesia spp. that infect bears (Ursidae), raccoons (Procyonidae) and canids (Canidae). Notably, the mitogenome structure consisted of six ribosomal large subunit-coding genes (LSU1-6) and three protein-coding genes (cytb, cox3 and cox1) arranged linearly.

CONCLUSIONS

Based on coupled morphological and genetic analyses, we describe a novel species of the genus Babesia, namely, Babesia ailuropodae n. sp., which infects giant pandas.

Hematological and plasma profiles and ticks and tick-borne pathogens in wild Formosan black bears (Ursus thibetanus formosanus)

BACKGROUND

The endangered Formosan black bear (Ursus thibetanus formosanus) is the largest native carnivorous mammal in Taiwan. Diseases, poor management, illegal hunting, and habitat destruction are serious threats to the survival of bear populations. However, studies on the impact of diseases on bear populations are limited. Therefore, this study aimed to establish a database of the hematological and plasma profiles of free-ranging Formosan black bears and investigate the occurrence of ectoparasites, blood parasites, and vector-borne pathogens.

METHODS

Formosan black bears were captured in Yushan National Park (YNP) and Daxueshan Forest Recreation Area (DSY) in Taiwan. Blood samples were collected from each bear for hematological analysis and plasma biochemistry using a hematology analyzer. Parasites and pathogens were detected using a thin blood smear with Wright-Giemsa staining and polymerase chain reaction (PCR) assay. Additionally, macroscopic ectoparasites were collected from bears to detect blood parasites and other pathogens. Moreover, the relationships between the bear variables (sex, age, and occurrence of parasites or pathogens), ectoparasites, and infectious agents were also analyzed.

RESULTS

In all, 21 wild bears (14 in YNP and 7 in DSY) were captured and released during the satellite tracking studies. Hematological analysis and plasma biochemistry indicated significant differences in white blood cells (WBC), segments, creatine kinase (CK), and lactate dehydrogenase (LDH) levels between foot snare and culvert-captured bears. Additionally, there were significant differences in total plasma protein (TPP), creatinine, Ca2+, Mg2+, and K+ levels between male and female bears. Moreover, pathogen-infected bears had significantly higher erythrocyte sedimentation rate (ESR; 30 min and 1 h) and globulin levels than uninfected bears. In total, 240 ticks were collected from 13 bears, among which eight adult tick species were identified, including Haemaphysalis flava, Haemaphysalis hystricis, Amblyomma testudinarium, Ixodes ovatus, Dermacentor taiwanensis, Haemaphysalis longicornis, Ixodes acutitarsus, Amblyomma javanense, and nymphs belonging to Haemaphysalis spp. PCR revealed that 13 (61.90%) and 8 (38.10%) bears harbored Hepatozoon ursi and Babesia DNA, respectively. Among the ticks examined, 157 (65.41%) and 128 (53.33%) samples were positive for H. ursi and Babesia, respectively.

CONCLUSIONS

To the best of our knowledge, this is the first study to establish a database of the hematological and plasma profiles of wild Formosan black bears and investigate ectoparasite infestation and Hepatozoon and Babesia spp.

INFECTION

In conclusion, these findings may serve as a reference for monitoring the health and population of locally endangered bears.

Development of a Multiplex Droplet Digital PCR Assay for the Detection of Babesia, Bartonella, and Borrelia Species

We describe the development, optimization, and validation of a multiplex droplet digital PCR (ddPCR) assay for the simultaneous detection of Babesia, Bartonella, and Borrelia spp. DNA from several sample matrices, including clinical blood samples from animals and humans, vectors, in-vitro infected human and animal cell lines, and tissues obtained from animal models (infected with Bartonella and/or B. burgdorferi). The multiplex ddPCR assay was able to detect 31 Bartonella, 13 Borrelia, and 24 Babesia species, including Theileria equi, T. cervi, and Cytauxzoon felis. No amplification of Treponema or Leptospira spp. was observed. Sensitivity of 0.2-5 genome equivalent DNA copies per microliter was achieved for different members of the Bartonella and Borrelia genus, depending on the species or matrix type (water or spiked blood DNA) tested. The ddPCR assay facilitated the simultaneous detection of co-infections with two and three vector-borne pathogens comprising four different genera (Babesia, Bartonella, Borrelia, and Theileria) from clinical and other sample sources.

Prevalence of protozoan parasites in small and medium mammals in Texas, USA

Wildlife interaction with humans increases the risk of potentially infected ticks seeking an opportunistic blood meal and consequently leading to zoonotic transmission. In the United States, human babesiosis is a tick-borne zoonosis most commonly caused by the intraerythrocytic protozoan parasite, Babesia microti. The presence of Babesia microti and other species of Babesia within Texas has not been well characterized, and the molecular prevalence of these pathogens within wildlife species is largely unknown. Small (e.g. rodents) and medium sized mammalian species (e.g. racoons) represent potential reservoirs for specific species of Babesia, though this relationship has not been thoroughly evaluated within Texas. This study aimed to characterize the molecular prevalence of Babesia species within small and medium sized mammals at two sites in East Texas with an emphasis on detection of pathogen presence in these two contrasting wild mammal groups at these sites. To that end, a total of 480 wild mammals representing eight genera were trapped, sampled, and screened for Babesia species using the TickPath layerplex qPCR assay. Two sites were selected for animal collection, including The Big Thicket National Preserve and Gus Engeling Wildlife Management Area. Molecular analysis revealed the prevalence of various Babesia and Hepathozoon species at 0.09% each, and Sarcocystis at 0.06% . Continued molecular prevalence surveys of tick-borne pathogens in Texas wild mammals will be needed to provide novel information as to which species of Babesia are most prevalent and identify specific wildlife species as pathogen reservoirs.

Babesia sp. infection in a zoo-housed polar bear (Ursus maritimus)

A 28-year-old female polar bear (Ursus maritimus) housed in a zoo in Upstate New York presented with acute inappetence and lethargy. The bear's condition rapidly deteriorated, and because laboratory testing indicated severe hepatic and renal disease, the bear was humanely euthanized. Examination of a blood smear from a sample collected just prior to euthanasia revealed the presence of intra-erythrocytic inclusions, which were identified as Babesia sp. by PCR. Although it is unclear if babesiosis contributed to this bear's clinical signs, this is the first report of Babesia sp. infection in this species. Zoological institutions exhibiting polar bears and located in tick-endemic areas, as well as managers of wild populations, should be aware of this species' susceptibility to babesiosis.