Epizootic and zoonotic helminths of the bobcat (Lynx rufus) in Illinois and a comparison of its helminth component communities across the American Midwest

A walk on the wild side: A review of the epidemiology of Toxocara canis and Toxocara cati in wild hosts

Toxocara species are cosmopolitan nematode parasites of companion, domestic and wild hosts. Of the 26 known species of Toxocara, only Toxocara canis and Toxocara cati are definitively zoonotic. The significance of wild carnivores as definitive hosts of T. canis and T. cati respectively, has received far less attention compared to domestic dogs and cats. Complex environmental changes have promoted increasing contact between wildlife, domestic animals and humans that can enhance the risk of pathogen spillover. This review lists a total of 19 species of wild canid host that have been shown to act as definitive hosts for T. canis and a total of 21 species of wild felid host. In general, the number of publications focusing on felid host species is fewer in number, reflecting the general paucity of data on T. cati. The wild canids that have received the most attention in the published literature include the red fox (Vulpes vulpes), the wolf (Canis lupus), and the golden jackal (Canis aureus). The wild felid species that has received the most attention in the published literature is the Eurasian lynx (Lynx lynx). Some non-canid and non-felid hosts also act as definitive hosts of Toxocara species. Certainly, red foxes would appear to be the most significant wild species in terms of their potential to transmit Toxocara to domestic dogs and humans via environmental contamination. This can be explained by their increasing population densities, encroachment into urban areas and their dietary preferences for a wide range of potential paratenic hosts. However, a major challenge remains to assess the relative importance of wild hosts as contributors to environmental contamination with Toxocara ova. Furthermore, one major constraint to our understanding of the significance of wildlife parasitism is a lack of access to samples, particularly from rare host species.

Endemic Paragonimus kellicotti infections in animals and humans in USA and Canada: Review and personal perspective

Infections with the lung fluke, Paragonimus kellicotti, have been diagnosed in a variety of domestic and wild animals and humans in USA and Canada. Although there are many species of Paragonimus in other parts of the world; P. kellicotti is the only species definitively diagnosed in USA and Canada. Fresh water snails (several species) and crayfish (mainly Orconectes spp.) are its intermediate hosts. Humans and animals become infected with P. kellicotti only by ingesting metacercariae encysted in the heart of crayfish. After ingestion, the fluke penetrates intestinal wall, enters peritoneal cavity, and reaches pleural cavity by direct penetration of diaphragm, 2-3 weeks post inoculation (p.i.). Young flukes penetrate lungs and become encysted in pulmonary tissue, often in pairs. Time to maturity is around 4-7 weeks p.i. Eggs are coughed up, swallowed, and are excreted in feces. Although the parasite has been known for more than a century, there has been an upsurge of human infections in the USA. Here, I review P. kellicotti infections in naturally infected hosts. Pathogenesis, diagnosis, and treatment in parasite-free cats and dogs experimentally infected P. kellicotti are reviewed to shed light on the pathogenesis of human paragonimiasis. Problems and challenges facing diagnosis of paragonimiasis, especially non-pulmonary infections, are discussed. Fluke stages are deposited in Smithsonian Museum.

A clinical review of human disease due to Paragonimus kellicotti in North America

Human autochthonous infections with the trematode Paragonimus kellicotti are increasingly being reported in North America, but the true prevalence and geographic distribution are unknown. Ingestion of raw crayfish is reported in most human cases, typically in the context of alcohol intoxication. Risk of infection varies depending on what part of the crayfish is ingested as metacercariae of P. kellicotti (>50% mature to adults) localize to the heart and pericardium of the crayfish. Reported human cases have manifested primarily in otherwise healthy young adults presenting with severe eosinophilic pneumonia, pleuritis, systemic symptoms, dermatologic lesions and cerebral involvement. However, it is likely that many infections go unreported due to lack of awareness, mild illness or the absence of rapid commercially available diagnostic tests. Promising advances have been made related to novel diagnostic targets. Conservation of these antigen targets among at least four Paragonimus species could make these antigens viable for diagnostic testing of P. kellicotti specifically as well as other Paragonimus species, but additional studies and funding investments are required. Public and physician awareness may have improved due to targeted education campaigns, but ongoing activities to raise awareness are needed, particularly in areas where cases have not been frequently reported to date.

Detection of Toxocara cati Larvae in a Common Buzzard (Buteo buteo) and in a Red Kite (Milvus milvus) in Basilicata Region, Italy

Toxocara cati is a common parasite of wild and domestic felines,and presents a cosmopolitan distribution. Adult parasites localize in the gut of the definitive host giving rise to the infection, which usually runs asymptomatic. These worms produce eggs that are excreted with feces into the environment, where they become a source of infection for paratenic hosts, such as mammals, birds, and invertebrates. In this brief communication, we report the detection of T. cati larvae in a common buzzard (Buteo buteo) and a red kite (Milvus milvus), in the Basilicata Region of Italy. This result may be important to define new pathways of spread and survival of T. cati in the wild.

Gastrointestinal and cardiorespiratory endoparasites in the wild felid guigna (Leopardus guigna) in Chile: Richness increases with latitude and first records for the host species

Guignas (Leopardus guigna) are small felids closely associated with native forest habitats. In fragmented landscapes, they use vegetation corridors and forest remnants to move across the landscape. In these contexts, guignas may increase contact probabilities with domestic animals, being therefore relevant to assess their pathogens and parasites. The aim of this study was to characterize the helminth fauna in the gastrointestinal tract and cardiorespiratory system of guignas from central and southern Chile. Between 2015 and 2018, 33 dead free-ranging guignas were found road-killed or were collected from wildlife rescue centers. Thirty-two gastrointestinal tracts and 32 cardiorespiratory organs were analyzed through direct analysis and artificial digestion. We found 81.8% (27/33) guignas were positive for helminth endoparasites (84.4% (27/32) positive for gastrointestinal parasites, 37.5% (12/32) positive for cardiorespiratory parasites). Fourteen parasites were identified (7 at genus level and 7 at species level), with Angiostrongylus sp., Molineus sp., Oslerus sp. and Troglostrongylus sp. as first records in guignas. The most prevalent parasites were the species Toxascaris leonina, Toxocara cati and Uncinaria stenocephala. Uncinaria stenocephala showed the highest intensity of infection. Multiparasitism was observed in 76% of the animals. Significant differences in richness of endoparasites and prevalence of cardiorespiratory parasites were found between geographic zones; higher values in the southern zone are possibly due to favorable environmental characteristics for endoparasite development. There were no statistically significant differences between sexes. All the parasites found in this study have been previously reported in domestic cats. These results are valuable to understand parasite transmission at the domestic-wildlife interface; the possibility of endoparasite transmission between domestic cats and guignas should be clarified with molecular analysis.

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The 81.8% of analyzed Leopardus guigna were positive for helminth parasites.

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First report of Angiostrongylus sp., Molineus sp., Oslerus sp. and Troglostrongylus sp. in guignas.

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Higher prevalence and diversity of cardiorespiratory parasites in guignas from southern Chile.

Toxocara spp. in dogs and cats in Canada

Toxocara spp. (T. canis and T. cati) are the dominant ascarids of domestic dogs and cats, respectively, in populated regions of southern Canada, where they pose animal and public health concerns. A review of the published literature indicated that prevalence of both parasites is declining in more recent studies (post 2000), likely due to changes in animal husbandry as well as use of anthelmintics. Geographically, prevalence was higher in the east (Atlantic), and in more southerly locations, possibly due to more favourable climate conditions for egg survival and development. At northern latitudes and in wild felids and canids in general, the non-zoonotic ascarid Toxascaris leonina appears to outcompete Toxocara spp.; however, T. leonina is rare in domestic cats in Canada. Prevalence of Toxocara spp. was higher in cats than dogs, shelter/rural/remote/feral/stray vs owned animals, and young vs adult animals, as has been observed in many other studies and regions of the world. While the regional prevalences in this review should be interpreted carefully in light of variation in diagnostic methods and study populations, they generally follow the same trends observed in a recent national study of shelter animals. This review is a timely summary of the state of the published knowledge on prevalence of Toxocara spp. in Canada, and highlights knowledge gaps to be addressed, including the northern distributional limits of these species in Canada, the potential for transmission to and from wildlife hosts, and the public health significance of the parasite in the mainstream Canadian population.

First confirmed case of Alaria alata mesocercaria in Eurasian lynx (Lynx lynx) hunted in Latvia

Trematode Alaria spp. have a complex life cycle that includes canids, mustelids, and felids as definitive hosts. However, several mammal species, besides acting as definitive hosts, may also act as paratenic hosts. Alaria spp. life cycles are well studied. Still, there is a lack of knowledge on one host significance as both-the paratenic and definitive host, especially in the case of Eurasian lynx (Lynx lynx). Previous studies have described Eurasian lynx as a definitive host for A. alata although the prevalence has always been low. The aim of the present study was to analyze the occurrence of A. alata in Eurasian lynx in Latvia. The viscera (n = 231) and muscle samples (n = 234) from Eurasian lynx were collected during the hunting seasons from 2004/2005 to 2017/2018. The prevalence of the adult A. alata in Eurasian lynx was 1.7%. However, mesocercariae infection in Eurasian lynx was detected for the first time. These findings suggest that the Eurasian lynx may serve both as paratenic and definitive host for A. alata.

Zoonotic nematodes of wild carnivores

For a long time, wildlife carnivores have been disregarded for their potential in transmitting zoonotic nematodes. However, human activities and politics (e.g., fragmentation of the environment, land use, recycling in urban settings) have consistently favoured the encroachment of urban areas upon wild environments, ultimately causing alteration of many ecosystems with changes in the composition of the wild fauna and destruction of boundaries between domestic and wild environments. Therefore, the exchange of parasites from wild to domestic carnivores and vice versa have enhanced the public health relevance of wild carnivores and their potential impact in the epidemiology of many zoonotic parasitic diseases. The risk of transmission of zoonotic nematodes from wild carnivores to humans via food, water and soil (e.g., genera Ancylostoma, Baylisascaris, Capillaria, Uncinaria, Strongyloides, Toxocara, Trichinella) or arthropod vectors (e.g., genera Dirofilaria spp., Onchocerca spp., Thelazia spp.) and the emergence, re-emergence or the decreasing trend of selected infections is herein discussed. In addition, the reasons for limited scientific information about some parasites of zoonotic concern have been examined. A correct compromise between conservation of wild carnivores and risk of introduction and spreading of parasites of public health concern is discussed in order to adequately manage the risk of zoonotic nematodes of wild carnivores in line with the 'One Health' approach.

Chronic Cytauxzoon felis infections in wild-caught bobcats (Lynx rufus)

Cytauxzoon felis, and the resulting disease, cytauxzoonosis, is an emerging threat to domestic cats in the Midwest and Southeastern United States. Domestic cats that survive cytauxzoonosis (or are subclinically infected) are chronically infected with C. felis, yet to date, there is no information relative to chronic infections in bobcats, the natural reservoir. Over a period of 3.5 years (2014-2017), we captured and re-captured 5 bobcats in southern Illinois. One bobcat was captured each year of trapping, 1 was caught in the first and third year and 3 were recaptured approximately 1 year apart. We screened bobcats for the presence of C. felis using a nested PCR that amplified the nuclear small subunit (SSU) 18S rRNA. In addition, we amplified and sequenced the internal transcribed spacers 1 and 2 (ITS1 and ITS2) to detect if the strains of C. felis in each bobcat were consistent over time. All bobcats were positive for C. felis at the initial and subsequent capture(s). Bobcats that were PCR-positive for C. felis had blood smears screened for the presence of C. felis; all PCR-positive bobcats had detectable parasites in blood smears. The strains of C. felis present were consistent each year in 4 of 5 bobcats indicating these bobcats remained infected during this period. One bobcat appeared to be infected with a different strain based on a polymorphism at a nucleotide in ITS1. Our study provides important details of the epizootiology of C. felis: bobcats are chronically infected and are not immune to reinfection with new strains of C. felis.

Trypanosoma cruzi strain TcIV infects raccoons from Illinois

BACKGROUND

The northern limits of Trypanosoma cruzi across the territory of the United States remain unknown. The known vectors Triatoma sanguisuga and T. lecticularia find their northernmost limits in Illinois; yet, earlier screenings of those insects did not reveal the presence of the pathogen, which has not been reported in vectors or reservoir hosts in this state.

OBJECTIVES

Five species of medium-sized mammals were screened for the presence of T. cruzi.

METHODS

Genomic DNA was isolated from heart, spleen and skeletal muscle of bobcats (Lynx rufus, n = 60), raccoons (Procyon lotor, n = 37), nine-banded armadillos (Dasypus novemcinctus, n = 5), Virginia opossums (Didelphis virginiana, n = 3), and a red fox (Vulpes vulpes). Infections were detected targeting DNA from the kinetoplast DNA minicircle (kDNA) and satellite DNA (satDNA). The discrete typing unit (DTU) was determined by amplifying two gene regions: the Spliced Leader Intergenic Region (SL), via a multiplex polymerase chain reaction, and the 24Sα ribosomal DNA via a heminested reaction. Resulting sequences were used to calculate their genetic distance against reference DTUs.

FINDINGS

18.9% of raccoons were positive for strain TcIV; the rest of mammals tested negative.

MAIN CONCLUSIONS

These results confirm for the first time the presence of T. cruzi in wildlife from Illinois, suggesting that a sylvatic life cycle is likely to occur in the region. The analyses of sequences of SL suggest that amplicons resulting from a commonly used multiplex reaction may yield non-homologous fragments.

The diversity and impact of hookworm infections in wildlife

Hookworms are blood-feeding nematodes that parasitize the alimentary system of mammals. Despite their high pathogenic potential, little is known about their diversity and impact in wildlife populations. We conducted a systematic review of the literature on hookworm infections of wildlife and analyzed 218 studies qualitative and quantitatively. At least 68 hookworm species have been described in 9 orders, 24 families, and 111 species of wild mammals. Black bears, red foxes, and bobcats harbored the highest diversity of hookworm species and Ancylostoma pluridentatum, A. tubaeforme, Uncinaria stenocephala and Necator americanus were the hookworm species with the highest host diversity index. Hookworm infections cause anemia, retarded growth, tissue damage, inflammation and significant mortality in several wildlife species. Anemia has been documented more commonly in canids, felids and otariids, and retarded growth only in otariids. Population- level mortality has been documented through controlled studies only in canines and eared seals although sporadic mortality has been noticed in felines, bears and elephants. The main driver of hookworm pathogenic effects was the hookworm biomass in a population, measured as prevalence, mean burden and hookworm size (length). Many studies recorded significant differences in prevalence and mean intensity among regions related to contrasts in local humidity, temperature, and host population density. These findings, plus the ability of hookworms to perpetuate in different host species, create a dynamic scenario where changes in climate and the domestic animal-human-wildlife interface will potentially affect the dynamics and consequences of hookworm infections in wildlife.

Concurrent Examination of Bobcats and Ticks Reveals High Prevalence of Cytauxzoon felis in Southern Illinois

Cytauxzoon felis is an intraerythrocytic apicomplexan of felids enzootic in the southeastern United States. In domestic cats (Felis catus), this parasite can result in the highly fatal disease cytauxzoonosis or bobcat fever. Bobcats (Lynx rufus) are the wild animal reservoir host. To date, the characterization of prevalence of C. felis in bobcats is mostly based on broad-scale surveys from hunter-harvested specimens collected across large geographic areas, usually consisting of multiple states. Detailed studies on the development, transmission, distribution, effects, and prevalence of C. felis in the tick vectors are scarce. To fill some of these gaps in the literature, such as prevalence in ticks and bobcats in a discrete region, we examined bobcats and ticks in an 8,000-km² portion of southern Illinois. We screened for C. felis using a nested polymerase chain reaction that amplifies a fragment of the nuclear small subunit (SSU) 18S rRNA. We screened 125 individual bobcats collected in southern Illinois from 2003 to 2015; of these, 70.6% were positive for C. felis. In addition, we screened 214 ticks of both vector species (Amblyomma americanum and Dermacentor variabilis) and detected C. felis in 15.6% of them; this prevalence is higher than reported by previous surveys. Our study reports the prevalence of C. felis in ticks and bobcats from south Illinois. We found that 70.6% of bobcats and 15.6% of ticks were infected with C. felis, which suggests risk of transmission to domestic cats.

Pathogen exposure varies widely among sympatric populations of wild and domestic felids across the United States

Understanding how landscape, host, and pathogen traits contribute to disease exposure requires systematic evaluations of pathogens within and among host species and geographic regions. The relative importance of these attributes is critical for management of wildlife and mitigating domestic animal and human disease, particularly given rapid ecological changes, such as urbanization. We screened > 1000 samples from sympatric populations of puma (Puma concolor), bobcat (Lynx rufus), and domestic cat (Felis catus) across urban gradients in six sites, representing three regions, in North America for exposure to a representative suite of bacterial, protozoal, and viral pathogens (Bartonella sp., Toxoplasma gondii, feline herpesvirus-1, feline panleukopenea virus, feline calicivirus, and feline immunodeficiency virus). We evaluated prevalence within each species, and examined host trait and land cover determinants of exposure; providing an unprecedented analysis of factors relating to potential for infections in domesticated and wild felids. Prevalence differed among host species (highest for puma and lowest for domestic cat) and was greater for indirectly transmitted pathogens. Sex was inconsistently predictive of exposure to directly transmitted pathogens only, and age infrequently predictive of both direct and indirectly transmitted pathogens. Determinants of pathogen exposure were widely divergent between the wild felid species. For puma, suburban land use predicted increased exposure to Bartonella sp. in southern California, and FHV-1 exposure increased near urban edges in Florida. This may suggest interspecific transmission with domestic cats via flea vectors (California) and direct contact (Florida) around urban boundaries. Bobcats captured near urban areas had increased exposure to T. gondii in Florida, suggesting an urban source of prey Bobcats captured near urban areas in Colorado and Florida had higher FIV exposure, possibly suggesting increased intraspecific interactions through pile-up of home ranges. Beyond these regional and pathogen specific relationships, proximity to the wildland-urban interface did not generally increase the probability of disease exposure in wild or domestic felids, empha- sizing the importance of local ecological determinants. Indeed, pathogen exposure was often negatively associated with the wildland-urban interface for all felids. Our analyses suggest cross-species pathogen transmission events around this interface may be infrequent, but followed by self-sustaining propagation within the new host species. virus; puma (Puma concolor); Toxoplasma gondii; urbanization.

Presencia de Toxascaris leonina y Cystoisospora felis en Lince Rojo (Lynx rufus escuinapae) en México

El Lince Rojo (Lynx rufus) es una especie de carnívoro mediano con una amplia distribución en Norteamérica, abarcando desde el sur de Canadá hasta México (Hall 1981). En la zona central de México se encuentra la subespecie Lynx rufus escuinapae, la cual habita principalmente el bosque mixto de pino-encino y bosque de oyamel (Romero 2005). De acuerdo a la Lista Roja de Especies Amenazadas de la UICN, la especie se encuentra catalogada como de Baja Preocupación (Kelly et al. 2008) y como especie En Peligro por el U.S. Fish and Wildlife Service (1973). La pérdida de hábitat y la cacería ilegal sonsus principales amenazas (Kelly et al. 2008).

North American paragonimiasis: epidemiology and diagnostic strategies

Paragonimiasis is a zoonotic, food-borne trematode infection that affects around 23 million people in Asia, Africa and the Americas. North American paragonimiasis, caused by Paragonimus kellicotti, is a common infection of crustacean-feeding mammals in parts of the USA and Canada. Although infection rates in crayfish are very high in some areas, human infections are rare and depend on the consumption of raw or undercooked crayfish. Human infections can be easily prevented and treated, but proper diagnosis of paragonimiasis is a problem. Paragonimus lung flukes often cause serious disease symptoms before they produce eggs that may be detectable in sputum, bronchoalveolar lavage, stool or histological sections by microscopy or PCR. Antibodies against selected Paragonimus proteins are detectable as early as 2-3 weeks after infection. Therefore, antibody serology is the most promising diagnostic approach for paragonimiasis in North America and elsewhere.