Molecular Detection and Genetic Variability of Hepatozoon canis in Golden Jackals (Canis aureus L. 1758) in Serbia.

Hepatozoon canis is a protozoan tick-borne parasite infecting domestic and wild canids, including foxes, wolves, and jackals. It is mainly found in dogs but has also been detected in several wild carnivores, including foxes, wolves, and jackals. Host transmission primarily occurs through the ingestion of infected ticks, typically Rhipicephalus sanguineus, with documented instances of transplacental transmission from infected females to cubs. In Serbia, the golden jackal is common throughout the country, and its population has increased in recent years. Previous research has documented the presence of several vector-borne pathogens in the jackal population in Serbia, so we conducted this study to determine the presence, prevalence, and genetic variability of H. canis. Over eleven years (2010-2020), 114 animal samples were collected from 23 localities in Serbia. A total of 90/114 (78.95%) jackals were positive for H. canis, and they came from 22 localities. Among 15 juveniles, almost half (6/15 (40%)) tested positive for H. canis. In addition to the high prevalence, high genetic variability of the pathogen was also found. According to the mutated positions, four sequence types (S4-S7) of H. canis were determined. Based on our earlier research on the grey wolf and on this study, it can be observed that various sequence types of H. canis circulate within wild canid populations in Serbia. The prevalence of H. canis infection in wild carnivores raises significant concerns for wildlife conservation and animal health. Infected animals may act as reservoirs for the disease, posing a potential risk to domestic animals by acting as a source of infection.

High Prevalence and Genetic Variability of Hepatozoon canis in Grey Wolf (Canis lupus L. 1758) Population in Serbia.

Wild canids are globally recognised as hosts and reservoirs of a large number of ecto- and endoparasites. Data that reveal the importance of the grey wolf (Canis lupus L.1758) in the spread of hepatozoonosis are very scarce. There are a large number of different potential host species that can be infected by Hepatozoon canis, but the most common are domestic and wild carnivores, such as dogs, jackals, foxes, and wolves. In this study, the epidemiological significance of the grey wolf as a host for the pathogen was analysed for the first time in Serbia, as well as the genetic variability of H. canis. The presence of H. canis in wolf spleens has been demonstrated using molecular methods. A total of 107 wolf spleen samples from 30 localities in Serbia were analysed. The presence of H. canis was confirmed in 62 (57.94%) individuals from 26 out of 30 localities. According to the analysis, the sampled H. canis sequences were found to be characterised by a certain heterogeneity. Based on five mutated nucleotide sites in the sequences, H. canis could be divided into five sequence types, S1 to S5. The five sequence types can potentially circulate in grey wolf populations as well as among other domestic and wild canids. This study is the first confirmation of the presence of H. canis in grey wolf populations in Serbia. Considering that the role of this vector-borne disease is poorly researched in wild carnivores, it is very important to indicate the role of this species in the circulation of this pathogen in natural ecosystems.

First Molecular Detection of Pneumocystis spp. in the Golden Jackal (Canis aureus).

Forty-six golden jackals (Canis aureus) were collected between November 2020 and February 2021 in five counties of Serbia. Lung samples were screened for the presence of Pneumocystis DNA by pan-Pneumocystis PCR on the mtLSU rRNA gene obtaining PCR products of 370 bp in length. Pneumocystis DNA was detected in the lungs from 6/46 (13.04%) golden jackals. Four were females and two were males; four were classified as adults and two as subadults. Positive samples were confirmed in 4/5 investigated counties. No gross pathologic lung lesions were observed in this study. The sequences of Pneumocystis spp. from golden jackals were identical to one another and showed the highest similarity with Pneumocystis spp. sequences of dogs (98% nucleotide identity). The genetic variation was comparable to Pneumocystis spp. of raccoon dogs (95-97% nucleotide identity), red foxes (91-95% nucleotide identity), ferrets (86% nucleotide identity), and another Pneumocystis type in dogs (P. canis Ck2, 81% nucleotide identity) was higher. Golden jackals may be carriers and may play a nonnegligible role in the spread of Pneumocystis spp. Although this finding cannot be directly related to any clinical manifestation or pathologic lesions, a possible role in the exacerbation of different pulmonary disorders should be considered.

First Report of Alveolar Hydatid Disease (Echinococcus multilocularis) in a Golden Jackal (Canis aureus).

BACKGROUND: Alveolar hydatid disease caused by the tapeworm Echinococcus multilocularis is a parasitic disease present in the northern hemisphere. Echinococcus multilocularis is a parasite of canid and felid carnivores as definitive hosts, and small mammals, particularly rodents as intermediate hosts. Other animal species and humans can be aberrant intermediate hosts for this parasite. It is known that besides acting as definitive hosts, domestic dogs can rarely become infected with the larval form of E. multilocularis and develop alveolar echinococcosis; however, a role of wild canids as aberrant intermediate hosts has not been documented until now. To the best of our knowledge the present paper provides the first description of alveolar hydatid disease in a golden jackal (Canis aureus). CASE PRESENTATION: Necropsy of the yearling female animal found a large, round, tumor-like mass, 20 cm in diameter, with a rough, multilobulated surface in the abdominal cavity, connected to the liver and omentum. On the cut surface this tumor-like lesion was multicystic, with a number of locular cavities filled with a clear yellowish to orange watery fluid and a large area of necrosis in the central part of the mass. Histopathology revealed multiple cystic spaces separated by fibrous sheaths and inflammatory cells-lymphocytes, plasma cells, neutrophil and eosinophil granulocytes. The cysts contained either pale, hyaline, eosinophilic laminar and occasionally amorphous, acellular, PAS-positive structures, or metacestodes with invaginated protoscolices. In several cysts round calcified bodies (calcareous corpuscles) were noted. Microscopic examination showed everted and inverted protoscolices which were attached to fragments of the brood capsule or free in hydatid fluid. By comparing consensus nucleotide sequence of 457 bp obtained by PCR reaction with sequences deposited in NCBI GenBank it is determined that it was 100% identical with E. multilocularis sequences under accession numbers MH259778.1, MH259776.1, AB668376.1, EU704124.1 and AB018440.2. CONCLUSIONS: The present paper provides a proof that the golden jackal, besides being a definitive host, can also serve as the aberrant intermediate host for E. multilocularis.

Heartworm Disease in Jackals: Unusual Location of Dirofilaria immitis.

PURPOSE: The knowledge of heartworm disease in free ranging wild canid populations is limited. As it is very difficult to monitor this disease in live animals, sporadic findings are mostly obtained by examining culled individuals of game species. METHODS: As a part of a broader study on jackal (Canis aureus) ecology in Serbia, the necropsy of legally hunted animals was performed in 2020. RESULTS: Two cases of heartworm infection with unusually located adult heartworms were diagnosed. The first case is an adult female jackal harvested in the vicinity of the capital city of Belgrade. Three adult specimens of Dirofilaria immitis were found in the right atrium of the heart, and nine adult specimens were located at an atypical site, in the vena cava caudalis. Very similar, the second case was in an adult female jackal harvested in the vicinity of Backi Monostor. In this case, six adult specimens of D. immitis were found in the right atrium of the heart and six more adult specimens in the vena cava caudalis. CONCLUSION: Although this nematode generally resides in the pulmonary arteries and the right ventricle of the heart, rare findings in other large blood vessels can occur. To the best of our knowledge, these are the first and only two confirmed cases of adult D. immitis found in vena cava caudalis in jackals in Europe.