Piroplasms in brown hyaenas (Parahyaena brunnea) and spotted hyaenas (Crocuta crocuta) in Namibia and South Africa are closely related to Babesia lengau

Genetic diversity of vector-borne pathogens in spotted and brown hyenas from Namibia and Tanzania relates to ecological conditions rather than host taxonomy

Background

Improved knowledge on vector-borne pathogens in wildlife will help determine their effect on host species at the population and individual level and whether these are affected by anthropogenic factors such as global climate change and landscape changes. Here, samples from brown hyenas (Parahyaena brunnea) from Namibia (BHNA) and spotted hyenas (Crocuta crocuta) from Namibia (SHNA) and Tanzania (SHTZ) were screened for vector-borne pathogens to assess the frequency and genetic diversity of pathogens and the effect of ecological conditions and host taxonomy on this diversity.

Methods

Tissue samples from BHNA (n = 17), SHNA (n = 19) and SHTZ (n = 25) were analysed by PCRs targeting Anaplasmataceae, Rickettsia spp., piroplasms, specifically Babesia lengau-like piroplasms, Hepatozoidae and filarioids. After sequencing, maximum-likelihood phylogenetic analyses were conducted.

Results

The relative frequency of Anaplasmataceae was significantly higher in BHNA (82.4%) and SHNA (100.0%) than in SHTZ (32.0%). Only Anaplasma phagocytophilum/platys-like and Anaplasma bovis-like sequences were detected. Rickettsia raoultii was found in one BHNA and three SHTZ. This is the first report of R. raoultii from sub-Saharan Africa. Babesia lengau-like piroplasms were found in 70.6% of BHNA, 88.9% of SHNA and 32.0% of SHTZ, showing higher sequence diversity than B. lengau from South African cheetahs (Acinonyx jubatus). In one SHTZ, a Babesia vogeli-like sequence was identified. Hepatozoon felis-like parasites were identified in 64.7% of BHNA, 36.8% of SHNA and 44.0% of SHTZ. Phylogenetic analysis placed the sequences outside the major H. felis cluster originating from wild and domestic felids. Filarioids were detected in 47.1% of BHNA, 47.4% of SHNA and 36.0% of SHTZ. Phylogenetic analysis revealed high genetic diversity and suggested the presence of several undescribed species. Co-infections were frequently detected in SHNA and BHNA (BHNA median 3 pathogens, range 1–4; SHNA median 3 pathogens, range 2–4) and significantly rarer in SHTZ (median 1, range 0–4, 9 individuals uninfected).

Conclusions

The frequencies of all pathogens groups were high, and except for Rickettsia, multiple species and genotypes were identified for each pathogen group. Ecological conditions explained pathogen identity and diversity better than host taxonomy.

Graphic Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-04835-x.

The Pathology of Pathogenic Theileriosis in African Wild Artiodactyls

The published literature on schizont-"transforming," or pathogenic theileriosis, in African wild artiodactyls is dated and based on limited information. Here the authors review the taxonomy, diagnosis, epidemiology, hematology, pathology, and aspects of control in various species. Molecular studies based on 18S and 16S rRNA gene sequences have shown that African wild artiodactyls are commonly infected with diverse Theileria spp., as well as nontheilerial hemoprotozoa and rickettsia-like bacteria, and coinfections with pathogenic and nonpathogenic Theileria species are often recorded. Although theileriosis is still confusingly referred to as cytauxzoonosis in many species, the validity of a separate Cytauxzoon genus in artiodactyls is debated. The epidemiology of theileriosis is complex; the likelihood of fatal disease depends on the interplay of parasite, vertebrate host, tick vector, and environmental factors. Roan calves (Hippotragus equinus) and stressed animals of all host species are more susceptible to fatal theileriosis. Even though regenerative anemia is common, peripheral blood piroplasm parasitemia does not correlate with disease severity. Other than anemia, common macroscopic lesions include icterus, hemorrhages (mucosal, serosal, and tissue), fluid effusions into body cavities, lung edema, and variably sized raised cream-colored foci of leukocyte infiltration in multiple organs. Histopathologic findings include vasocentric hyperproliferation and lysis of atypical leukocytes with associated intracellular schizonts, parenchymal necrosis, hemorrhage, thromboembolism, and edema. Immunophenotyping is required to establish the identity of the schizont-transformed leukocytes in wild ungulates. Throughout the review, we propose avenues for future research by comparing existing knowledge on selected aspects of theileriosis in domestic livestock with that in African wild artiodactyls.

Molecular identification of Ehrlichia, Anaplasma, Babesia and Theileria in African elephants and their ticks

Although historical records indicate the presence of Ehrlichia and Babesia in African elephants, not much is known about their prevalence and diversity in elephants and their ticks, Amblyomma thollonii and Rhipicephalus humeralis. We amplified and sequenced the hypervariable V4 region of the 18S rRNA gene of Babesia and Theileria and the heat shock protein gene (groEL) of Ehrlichia/Anaplasma in DNA extracted from elephant blood (n = 104) and from elephant ticks (n = 52). Our results showed that the African elephants were infected with a novel Babesia spp. while A. thollonii was infected with Theileria bicornis and Theileria cf. velifera. This is the first record of T. bicornis; a protozoan that is linked to fatal infection in rhinoceros in a tick. Elephants and their ticks were all infected with a species of Ehrlichia like that identified in Japanese deer. The prevalence of Babesia spp., Theileria spp. and Ehrlichia spp. in ticks was higher than that of their elephant hosts. About 13.5% of elephants were positive for Theileria or Babesia while 51% of A. thollonii ticks and 27% of R. humeralis ticks were positive for Theileria or Babesia. Moreover, 5.8% of elephants were positive for Ehrlichia or Anaplasma compared to 19.5% in A. thollonii and 18% in R. humeralis. There was no association between the positive result in ticks and that of their elephant hosts for either Babesia spp., Theileria spp. or Ehrlichia spp. Our study reveals that the African elephants are naturally infected with Babesia spp and Ehrlichia spp and opens up an opportunity for further studies to determine the role of elephant as reservoirs of tick-borne pathogens, and to investigate their potential in spreading these pathogens as they range extensively. The presence of T. bicornis in A. thollonii also suggests a need for experiments to confirm its vector competence.

SERUM BIOCHEMISTRY VALUES AND SELECT SEROLOGIC SCREENING OF BROWN HYENAS ( PARAHYAENA BRUNNEA) FROM THE NAMIB DESERT, NAMIBIA

Blood from 30 free-ranging brown hyenas ( Parahyaena brunnea) was collected for biochemical analysis and select serologic screening in Namibia from 1997 to 2010. Age was found to have an influence on several biochemical parameters that may be related to growth, a developing immune system, and differences in diet. Seasonal differences in diet of coastal brown hyenas also had an overall significant effect on lipemia values, and differences in stress due to varying capture methods could be associated with an increase in glucose and creatinine kinase. Comparisons among hyena species from published data were inconclusive, as some samples may have been derived from captive populations and individuals. Sera were tested for antibodies against 18 pathogens. Antibodies were not detected for most pathogens, but the proportion of sera containing antibodies against canine adenovirus-1 (CAV-1) and canine adenovirus-2 (CAV-2) was 65% and 84%, respectively. There was no effect of sex, age, year of sampling, or contact with domestic dogs, indicating that CAV-1 or CAV-2 may be enzootic. The prevalence of antibodies to canine distemper virus (CDV) was 43%, and older brown hyenas were 6.9 times more likely to have been exposed to CDV, adjusting for year of sampling and degree of estimated contact with domestic dogs, suggesting epizootic outbreaks. This study is the first to present biochemical reference intervals for wild brown hyenas and provides an indication of disease exposure in this species.

Diversity of Anaplasma and Ehrlichia/Neoehrlichia Agents in Terrestrial Wild Carnivores Worldwide: Implications for Human and Domestic Animal Health and Wildlife Conservation

Recently, the incidence and awareness of tick-borne diseases in humans and animals have increased due to several factors, which in association favor the chances of contact among wild animals and their ectoparasites, domestic animals and humans. Wild and domestic carnivores are considered the primary source of tick-borne zoonotic agents to humans. Among emergent tick-borne pathogens, agents belonging to family Anaplasmataceae (Order Rickettsiales) agents stand out due their worldwide distribution and zoonotic potential. In this review we aimed to review the genetic diversity of the tick-transmitted genera Ehrlichia, Anaplasma and "Candidatus Neoehrlichia sp." in wild carnivores Caniformia (Canidae, Mustelidae and Ursidae) and Feliformia (Felidae, Hyanidae, Procyonidae and Viverridae) worldwide, discussing the implications for human and domestic animal health and wildlife conservation. Red foxes (Vulpes vulpes) have been identified as hosts for Anaplasma spp. (A. phagocytophilum, Anaplasma ovis, A. platys), Ehrlichia canis and "Candidatus Neoehrlichia sp." (FU98 strain) and may contribute to the maintaenance of A. phagocytophilum in Europe. Raccoons (Procyon lotor) have been reported as hosts for E. canis, A. bovis, "Candidatus Neoehrlichia lotoris" and A. phagocytophilum, and play a role in the maintenance of A. phagocytophilum in the USA. Raccoon dogs (Nyctereutes procyonoides) may play a role as hosts for A. bovis and A. phagocytophilum. New Ehrlichia and/or Anaplasma genotypes circulate in wild canids and felids from South America and Africa. While Ehrlichia sp. closely related to E. canis has been reported in wild felids from Brazil and Japan, Anaplasma sp. closely related to A. phagocytophilum has been detected in wild felids from Brazil and Africa. Red foxes and mustelids (otters) are exposed to E. canis in countries located in the Mediaterranean basin, probably as a consequence of spillover from domestic dogs. Similarly, E. canis occurs in procyonids in North (raccoons in USA, Spain) and South (Nasua nasua in Brazil) Hemispheres, in areas where E. canis is frequent in dogs. While "Candidatus Neoehrlichia lotoris" seems to be a common and specific agent of raccoons in the USA, "Candidatus Neoehrlichia sp." (FU98 strain) seems to show a broader range of hosts, since it has been detected in red fox, golden jackal (Canis aureus) and badger (Meles meles) in Europe so far. Brown (Ursus arctos) and black (Ursus americanus) bears seem to play a role as hosts for A. phagocytophilum in the North Hemisphere. Anaplasma bovis has been detected in wild Procyonidae, Canidae and Felidae in Asia and Brazil. In order to assess the real identity of the involved agents, future works should benefit from the application of MLST (Multi Locus Sequence Typing), WGS (Whole Genome Sequencing) and NGS (Next Generation Sequencing) technologies aiming at shedding some light on the role of wild carnivores in the epidemiology of Anaplasmataceae agents.

A survey of Babesia spp. and Hepatozoon spp. in wild canids in Israel

Background

Babesia spp. and Hepatozoon spp. are apicomplexan parasites that infect a variety of animals, including canids. Their life-cycle includes an invertebrate hematophagous vector as a definitive host and vertebrates as intermediate hosts. The aims of this study were to investigate the prevalence and risk factors for Babesia spp. and Hepatozoon spp. infections in wild golden jackals (Canis aureus) and red foxes (Vulpes vulpes) in Israel and to compare spleen with blood sample polymerase chain reaction (PCR) for the detection of infection.

Results

Blood and spleen samples from 109 golden jackals and 21 red foxes were tested by PCR for the detection of Babesia spp. and Hepatozoon spp. using primers for the 18S ribosomal (r) RNA gene. Hepatozoon canis was detected in 50/109 (46%) of the jackals and 9/21 (43%) of the foxes. “Babesia vulpes” (the Babesia microti-like piroplasm) was detected in 4/21 (19%) of the foxes and in none of the jackals. A previously unknown genotype termed Babesia sp. MML related to Babesia lengau (96–97% identity) was detected in 1/109 (1%) of the jackals and 4/21 (19%) of the foxes. Further characterization of this genotype carried out by PCR of the rRNA internal transcribed spacer 2 (ITS2) indicated that it had only 87% identity with the B. lengau ITS2. Sex (male or female), age (juvenile or adult) and geographic zone (North, Central or South Israel) were not found to be significant risk factors for these protozoan infections. The prevalence of “B. vulpes” and Babesia sp. MML infections was significantly higher in foxes compared to jackals (χ² = 15.65, df = 1, P < 0.005), while there was no statistically significant difference in the rate of H. canis infection between these two canid species. A fair agreement beyond chance between identification in the blood and spleen of H. canis was found in 21 animals from which both blood and spleen samples were available (k = 0.33).

Conclusions

This study describes a high prevalence of H. canis infection in foxes and jackals and is the first report of “B. vulpes” infection in Israel, an area where Ixodes spp. are rare. It describes infection with a previously unknown genotype of Babesia related to B. lengau from Africa.