Neotropical Zoonotic Parasites in Bush Dogs (Speothos venaticus) from Upper Paraná Atlantic Forests in Misiones, Argentina

Neglected zoonotic helminthiases in wild canids: new insights from South America

The global threat of neglected tropical diseases (NTDs) constitutes a public health issue in underdeveloped countries. Zoonotic helminthiases are the most common human NTD agents in developing countries in sub-Saharan Africa, Asia, and the Americas, causing a global burden of disease that exceeds that of more recognized infectious diseases such as malaria and tuberculosis. Wild canids are well-known mammals that act as natural reservoirs of zoonotic-relevant helminthiasis worldwide, thus playing a pivotal role in their epidemiology and transmission to humans. Here we evaluate the occurrence of zoonotic gastrointestinal helminths in two Neotropical wild canid species from the Amazonian and Andean regions of Colombia, i.e., the bush dog (Speothos venaticus) and the crab-eating fox (Cerdocyon thous). We recovered tapeworm proglottids from bush dog fecal samples and identified them molecularly as the canine-specific lineage of Dipylidium caninum by using cytochrome c oxidase subunit I (cox1) gene sequences. Moreover, examination of a crab-eating fox during necropsy revealed the presence of non-embryonated eggs of the neglected nematode Lagochilascaris cf. minor, in addition to eggs and gravid proglottids of the cestode Spirometra mansoni. These findings represent the first report of zoonotic-relevant cestodes, i.e., D. caninum ("canine genotype"), S. mansoni, and the nematode L. cf. minor, in bush dogs and crab-eating foxes as final hosts. The occurrence of these zoonotic helminthiases in wild canid species calls for regular monitoring programs to better understand the epidemiology and transmission routes of neglected dipylidiasis, lagochilascariosis, and sparganosis in South America.

Heterologous microsatellite primers are informative for paca (Cuniculus paca), a large rodent with economic and ecological importance

OBJECTIVE

This study was designed to facilitate genetic studies that would allow information on population structure and genetic diversity of natural or captive stocks of paca (Cuniculus paca), a species of ecological and socioeconomic importance, by testing cross-amplification of 20 heterologous microsatellite primer pairs developed for guinea pigs (Cavia porcellus) and capybara (Hydrochoerus hydrochaeris).

RESULTS

Those primers that showed the best amplification profile in blood samples were subsequently applied to scats and saliva samples, to evaluate their efficiency. Of the 13 microsatellite pairs that amplified in blood, one-third (32%) were successfully amplified in saliva and scat samples. This initial work demonstrates successful cross-amplification in paca providing a solid and promising foundation for future genetic studies with this species. The ability to quantify genetic diversity using noninvasive samples from free-ranging paca is essential to developing applied management strategies for this large neotropical rodent that is not only a prey favored by wide-ranging carnivores [e.g., jaguar (Panthera onca), puma (Puma concolor)], but is also a species targeted by illegal hunting and wildlife trade.

History of Toxocara and the associated larva migrans

This review covers the systematics and nomenclature of the Ascaridoid genus toxocara, and more specifically the species Toxocara canis and Toxocara cati. Also discussed is the discovery of the persistence of these larvae in the tissues of paratenic hosts, and the role that other species of this genus might or could play in other such hosts; including those where the life cycle has been described, i.e., Toxocara vitulorum, Toxocara pteropodis, Toxocara mackerrasae, and Toxocara tanuki. Also examined is the work that led to the realization that the larval stage leaving the egg actually being a third rather than a second stage larva. Also discussed on the work showing that the larvae can persist in paratenic host with remarkable longevity without undergoing any morphological change for years and that these larvae can be transmitted from one paratenic host to another by ingestion. People are usually infected by the ingestion of eggs containing third-stage larvae, but infections also occur on occasions from the ingestion of uncooked paratenic hosts.

Parasitologic examination and associated risk factors of domestic dogs at the domestic-wildlife interface in the Iberá wetlands Ecoregion, Argentina

The wildlife-domestic interface represents points of contact between wild animals and human-associated domestic animals, and provides opportunities for the dissemination and transmission of parasitic agents. Domestic dogs are reservoirs of parasitic agents, many of which are capable of infecting wild animals. To better investigate this potential risk at the Iberá wetlands eco-region, fecal samples from dogs present at the wildlife-domestic interface of two protected areas in Corrientes province, Argentina were examined. The prevalence of intestinal parasites and overall generic richness were examined and associations with age, sex, body condition, anthelmintic treatments and dog movement restriction were explored. From August-September 2017, questionnaires were carried out and fecal samples collected from 51 dogs at the interface zones. The overall estimated prevalence of gastrointestinal parasites was 63%. Nine genera of helminths and four protozoans were found in the examined dogs, many of which are known to infect wild carnivores and several have zoonotic potential. Ancylostoma and Isospora were the most prevalent genera. Freedom to roam was positively associated with prevalence and richness. From all dogs in our study, only a small proportion (17%) is subjected to some degree of movement restriction, while most dogs were free roaming. Veterinary health care and treatment was also extremely limited. The findings of this study revealed conditions of high prevalence of gastrointestinal parasites, lack of veterinary care and unrestricted roaming; all circumstances that suggest that dogs that live at these interface zones pose an infection risk to sympatric wildlife.

How Behavior of Nontarget Species Affects Perceived Accuracy of Scat Detection Dog Surveys

Detection dogs, specially trained domestic dogs (Canis familiaris), have become a valuable, noninvasive, conservation tool because they remove the dependence of attracting species to a particular location. Further, detection dogs locate samples independent of appearance, composition, or visibility allowing researchers to collect large sets of unbiased samples that can be used in complex ecological queries. One question not fully addressed is why samples from nontarget species are inadvertently collected during detection dog surveys. While a common explanation has been incomplete handler or dog training, our study aimed to explore alternative explanations. Our trials demonstrate that a scat’s genetic profile can be altered by interactions of nontarget species with target scat via urine-marking, coprophagy, and moving scats with their mouths, all pathways to contamination by nontarget species’ DNA. Because detection dogs are trained to locate odor independent of masking, the collection of samples with a mixed olfactory profile (target and nontarget) is possible. These scats will likely have characteristics of target species’ scats and are therefore only discovered faulty once genetic results indicate a nontarget species. While the collection of nontarget scats will not impact research conclusions so long as samples are DNA tested, we suggest ways to minimize their collection and associated costs.

Natural infection in Pampas fox (Lycalopex gymnocercus) by Lagochilascaris major Leiper, 1910 (Nematoda: Ascarididae) in Buenos Aires, Argentina

Lagochilascariosis is an emerging parasitic disease limited to the American continent, caused by nematodes of the genus Lagochilascaris. Its life cycle is heteroxenous, involving natural definitive hosts (wild carnivores), accidental hosts (domestic carnivores and humans), and intermediate hosts (rodents). Here we report, for the first time, the occurrence of Lagochilascaris major in female of a Pampas fox (Lycalopex gymnocercus) which was found in the Mar Chiquita basin, Buenos Aires province, Argentina. At necropsy, multiple Lagochilascaris larvae and several adults (1 female and 5 male) were observed inserted in the mucosa of the trachea and a male was also collected in the stomach. The diagnosis was made by observing the different stages with optical microscopy, by scanning electron microscopy of adult males and coproparasitological analysis. Although cases of lagochilascariosis have been reported in wildlife in different countries of the American continent, in Argentina, cases are really rare and were only found in domestic cats. Graphical abstract ᅟLagochilascariosis is an emerging parasitic disease limited to the American continent. In Argentina, sporadic cases of Lagochilascariosis were reported in domestic cats but this work represents the first record in a wild carnivore (L. gymnocercus) naturally infected with L. major.