Endoparasitic fauna of two South American foxes in Chile: Lycalopex culpaeus and Lycalopex griseus

Parasitic findings on threatened pudu deer from Central Chile accounts first genetic characterization of lice parasitizing P. puda in Chile and the first molecular report of Taenia hydatigena metacestodes in this species

Southern pudu (Pudu puda) is a threatened endemic deer of the temperate forests of Chile. In recent years pudu populations rates have decreased mainly due to anthropogenic causes including forest loss and landscape fragmentation. In this context, the parasitic fauna of Chilean pudu has been scarcely investigated. The aim of this study was to determine the parasitic status of rescued pudu n = 13 from its natural habitat in Central Chile (Maule region) during March 2022 and June 2023 by applying morphological, histopathological, and molecular analyses. As result, we report the presence of transmission of parasites from dogs to pudus as showed by the presence of metacestodes of the parasite Taenia hydatigena on omentum, liver, and pleura of pudus during postmortem examinations, being the first molecular report on the presence of this parasite on Chilean pudu. Meanwhile, ectoparasite examinations determined the presence of chewing and sucking lice on pudu exemplars here analysed. Molecular and phylogenetic analysis of lice revealed new insights on Bovicola and Anoplura lice parasitizing P. puda in Chile, equally being the first genetic characterization of lice parasitizing pudu exemplars in Chile. In addition, parasite loads of lice and metacestodes were analysed. However, no statistically significance was observed when comparing environmental and individual traits influence on parasite load variation. Overall, the study area is the northern limit of habitat distribution of this specie in Chile and we here provide novel information on pudu deer parasites, thus making a useful and valuable contribution to the parasitological knowledge on this threatened species.

Centrorhynchus spp. (Acanthocephala) in South America: new anuran record and checklist of vertebrate hosts

The aim of this study was to record Centrorhynchus sp. associated with the exotic species Aquarana catesbeiana (bullfrog) in southern Brazil and to present a checklist of vertebrate hosts in South America. Twenty-nine adults and juveniles of A. catesbeiana were collected in Capão do Leão, state of Rio Grande do Sul, Brazil, between October 2019 and December 2020. We found 275 specimens of Centrorhynchus sp. cystacanths in the stomach musculature and coelomic cavity of 55.1% of hosts (16). There was no significant differences in the prevalence and mean intensity of infection with cystacanths when compared males and females of A. catesbeiana. The prevalence was significantly higher in adults than in juveniles. The checklist presents 106 species of vertebrate hosts and 14 taxa of Centrorhynchus recorded in nine South American countries. Avian were the main definitive hosts of Centrorhynchus spp. and snakes Dipsadidae, anurans Hylidae and Leptodactylidae the main paratenic hosts in South America. This is the first record of Centrorhynchus cystacanths in A. catesbeiana in the South America. The study provides tools to help understand the parasitic relationships between species of Centrorhynchus and A. catesbeiana and other hosts in areas where bullfrog have been introduced.

Co-infection patterns of vector-borne zoonotic pathogens in owned free-ranging dogs in central Chile

We investigated the co-occurrence of the nine of the most relevant canine vector-borne pathogens (CVBP) using conventional and real-time PCR and evaluated risk factors and potential non-apparent haematological alterations associated with co-infection in 111 rural, owned, free-ranging dogs in the Metropolitan Region of Chile.

At least one pathogen was detected in 75% of the dogs. DNA of Anaplasma platys (Ap; 36%), Candidatus Mycoplasma haematoparvum (CMhp; 31%), Mycoplasma haemocanis (Mhc; 28%), Trypanosoma cruzi (17%), Leishmania spp. (4.5%), and Acanthocheilonema reconditum (1%) was detected. All dogs were negative for Ehrlichia spp., Rickettsia spp., Bartonella spp., Piroplasmida, and Hepatozoon spp. Thirty-eight dogs (34%) were coinfected. CMhp was involved in 71%, Mhc in 58%, and Ap in 50% of the co-infections. The most common co-infection pattern was CMhp–Mhc (37% of the cases). The prevalence of Ap was higher in juvenile than in adult dogs, whereas the opposite was found for CMhp and Mhc. Adult dogs were four times more likely of being co-infected than juveniles. Co-infected animals showed higher white blood cell count, segmented neutrophil count, and GGT levels than non-co-infected dogs. Clinically healthy but infected dogs may act as reservoirs of CVBP, and their free-ranging behavior would facilitate the spread of these pathogens to other dogs as well as human beings or wild carnivores.

Large-scale survey for canine vector-borne parasites in free-ranging dogs and foxes from six diverse bioclimatic regions of Chile

Chile is a large country with a marked range of climate conditions that make it an ideal scenario for the study of vector-borne parasites (VBPs); however, knowledge about their distribution is limited to a few confined areas of this country. The presence of Hepatozoon spp., piroplasmids, Leishmania spp. and filarioids was investigated through molecular and serological methods in blood and serum samples of 764 free-ranging rural dogs, 154 Andean foxes (Lycalopex culpaeus), and 91 South American grey foxes (Lycalopex griseus) from six bioclimatic regions across Chile. Hepatozoon spp. DNA was exclusively detected in foxes (43% prevalence), including sequences closely related to Hepatozoon felis (24.1%; only Andean foxes), Hepatozoon americanum (16.2%; only grey foxes), and Hepatozoon canis (1.25%; in one grey fox). Risk factor assessment identified a higher probability of Hepatozoon infection in juvenile foxes. DNA of piroplasmids was detected in 0.7% of dogs (Babesia vogeli) but in no fox, whilst antibodies against Babesia sp. were detected in 24% of the dogs and 25% of the foxes, suggesting a wider circulation of canine piroplasmids than previously believed. A positive association between the presence of antibodies against Babesia and high Rhipicephalus sanguineus sensu lato burden was observed in dogs. Leishmania spp. DNA and antibodies were detected in 0.8% and 4.4% of the dogs, respectively. Acanthocheilonema reconditum was the only blood nematode detected (1.5% of the dogs and no fox). Differences in prevalence among bioregions were observed for some of the VBPs. These results expand our knowledge about the occurrence of vector-borne parasites in Chile, some of which are firstly reported herein. This information will facilitate the diagnosis of vector-borne diseases in domestic dogs and improve the control measures for both domestic and wild canids.

Morphological and molecular evidence of Oslerus osleri (Nematoda: Filaroididae) in the Andean fox (Lycalopex culpaeus)

Oslerus osleri is a cosmopolitan filaroid nematode that parasitizes the respiratory system of domestic and wild canids. Natural infection by O. osleri is reported in the Andean fox (Lycalopex culpaeus) in this study. Nematodes, enclosed in small and compact fibrous nodules of 1 to 5 mm in diameter, were found on the surface of the trachea near the bronchial bifurcation on four Andean foxes during necropsy (one from Cuzco, Peru and three from Northwestern Patagonia in Argentina). The nematodes were identified as O. osleri by morphological and molecular methods. Ribosomal and mitochondrial DNA analyses were performed amplifying the second internal transcribed spacer region (ITS-2), the partial cytochrome c oxidase 1 (cox1), and the large subunit of nuclear ribosomal RNA (LSU rRNA) genes. Sequences of the ITS-2 and LSU rRNA had a genetic variation of 1.5% and 1.0%, respectively, with previous sequences of O. osleri registered in Genbank. This is the first amplification of the cox1 gene of O. osleri and demonstrated an identity of 92% to Perostrongylus falciformis (KY365437), and 90% to Angiostrongylus cantonensis (KY779735) and Angiostrongylus costaricensis (AP017675).