Baylisascaris procyonis in raccoons (Procyon lotor) from North Carolina and current status of the parasite in the USA

Prevalence of Baylisascaris procyonis in wild rodents in central Georgia, USA

Raccoon roundworm, Baylisascaris procyonis, is a zoonotic parasite of raccoons (Procyon lotor) that needs a One Health approach to better inform risks to human and animal health. The few studies on B. procyonis in wild rodents have primarily focused on white-footed mice (Peromyscus leucopus). This study aimed to determine the prevalence and rodent host range of B. procyonis in Georgia (USA) and investigate differences in prevalence at urban/fragmented sites and rural/agriculture sites. We sampled 99 rodents of five species. Larvae were recovered from seven of 78 (9.0%) white-footed mice with a mean of 4.4 larvae (range 1-12). One mouse had a single larva in the brain. Prevalence was not different between urban and rural sites. This report extends the geographic range of this parasite and confirms that rodents serve as paratenic hosts in the southern range. Therefore, baylisascariasis should be considered a differential for neurologic domestic animals, wildlife, or people in this region.

Morphology and ASAP analysis of the important zoonotic nematode parasite Baylisascaris procyonis (Stefahski and Zarnowski, 1951), with molecular phylogenetic relationships of Baylisascaris species (Nematoda: Ascaridida)

Species of Baylisascaris (Nematoda: Ascarididae) are of great veterinary and zoonotic significance, owing to cause Baylisascariosis or Baylisascariasis in wildlife, captive animals and humans. However, the phylogenetic relationships of the current 10 Baylisascaris species remain unclear. Moreover, our current knowledge of the detailed morphology and morphometrics of the important zoonotic species B. procyonis is still insufficient. The taxonomical status of B. procyonis and B. columnaris remains under debate. In the present study, the detailed morphology of B. procyonis was studied using light and scanning electron microscopy based on newly collected specimens from the raccoon Procyon lotor (Linnaeus) in China. The results of the ASAP analysis and Bayesian inference (BI) using the 28S, ITS, cox1 and cox2 genetic markers did not support that B. procyonis and B. columnaris represent two distinct species. Integrative morphological and molecular assessment challenged the validity of B. procyonis, and suggested that B. procyonis seems to represent a synonym of B. columnaris. Molecular phylogenetic results indicated that the species of Baylisascaris were grouped into 4 clades according to their host specificity. The present study provided new insights into the taxonomic status of B. procyonis and preliminarily clarified the phylogenetic relationships of Baylisascaris species.

Raccoon Roundworm (Baylisascaris procyonis) Undetected in Endangered Key Largo Woodrat (Neotoma floridana smalli) Endemic Range

Raccoon roundworm (Baylisascaris procyonis) negatively affects woodrat (Neotoma spp.) populations but is not known to occur in the endemic range of endangered Key Largo woodrats (Neotoma floridana smalli). Rectal swabs from 23 raccoons (Procyon lotor) in Key Largo were screened for raccoon roundworm by PCR. All tests were negative, suggesting continued absence.

Drug Repurposing of Quisinostat to Discover Novel Plasmodium falciparum HDAC1 Inhibitors with Enhanced Triple-Stage Antimalarial Activity and Improved Safety

Our previous work found that the clinical histone deacetylase (HDAC) inhibitor quisinostat exhibited a significant antimalarial effect but with severe toxicity. In this work, 35 novel derivatives were designed and synthesized based on quisinostat as the lead compound, and their in vitro antimalarial activities and cytotoxicities were systematically evaluated. Among them, JX35 showed potent inhibition against both wild-type and multidrug-resistant parasite strains and displayed a significant in vivo killing effect against all life cycles of parasites, including the blood stage, liver stage, and gametocyte stage, indicating its potential for the simultaneous treatment, chemoprevention, and blockage of malaria transmission. Compared with quisinostat, JX35 exhibited stronger antimalarial efficacy, more adequate safety, and good pharmacokinetic properties. Additionally, mechanistic studies via molecular docking studies, induced PfHDAC1/2 knockdown assays, and PfHDAC1 enzyme inhibition assays jointly indicated that the antimalarial target of JX35 was PfHDAC1. In summary, we discovered the promising candidate PfHDAC1 inhibitor JX35, which showed stronger triple-stage antimalarial effects and lower toxicity than quisinostat.

Spatio-temporal clustering of Baylisascaris procyonis, a zoonotic parasite, in raccoons across different landscapes in southern Ontario

Baylisascaris procyonis, the raccoon roundworm, is a parasite found throughout North America and parts of Europe. More than 150 species of mammals and birds including humans can develop neurological disease following infection with the larval stage of this parasite. To investigate whether B. procyonis infections in raccoons cluster in space, time, or space-time, we used data from 1353 Ontario raccoons submitted to the Canadian Wildlife Health Cooperative between 2013 and 2016. We identified a significant spatial cluster of increased infection prevalence in southern Ontario centered over a major metropolitan area, as well as a significant cluster of decreased infection prevalence in a primarily agricultural region in southwestern Ontario. Furthermore, we identified statistically significant temporal clusters in the fall in annual scans of data from 2014, 2015 and 2016. Examination of both Bernoulli and space-time permutation models for space-time analysis suggested that the purely spatial and temporal clusters were not explained by relatively short and spatially discrete events in space-time. The identified annual temporal clusters are consistent with previous research on the seasonality of B. procyonis infection in raccoons. Recognition of the spatial infection clusters will help identify potential geographic and anthropogenic factors associated with the occurrence of B. procyonis infection in raccoons. Given the zoonotic potential of this parasite, identification of a cluster of high infection prevalence in a major metropolitan area has implications for public education and risk management strategies.

Raccoon roundworm prevalence (Baylisascaris procyonis) at the North Carolina Zoo, USA

Baylisascaris procyonis is an important zoonotic nematode of raccoons (Procyon lotor). Infection with this parasite has important health implications for humans, zoo animals, and free-ranging wildlife. As a large, natural habitat zoo, the North Carolina Zoo (NC Zoo) coexists with native wildlife. Raccoons are abundant at the NC Zoo and the prevalence of B. procyonis is unknown. Raccoon latrines were located through employee reporting and systematic searching throughout the zoo and sampled for B. procyonis in October and November of 2018 and 2019. Parasite prevalence, latrine location, substrate category and latrine persistence were recorded. Thirty-three latrines were located in 2018 and eight new latrines in 2019 while four latrines from the prior year were no longer available to be sampled. Of the 29 latrines sampled over the two years, 16 (55%) persisted for at least one year. The majority of the latrines were found on natural substrate with rock showing the highest preference. Just over half (n = 21 of 41 total) of the active latrines in the study were in or immediately adjacent to animal enclosures. Two latrines were found in public areas including one contaminating children’s play equipment. Additionally, fresh fecal samples were collected from five adult raccoons presented to the zoo’s veterinary clinic in 2018 and 2019. All fecal samples tested by centrifugal flotation for both years were negative for B. procyonis. The results of this study show the value of field sampling to properly assess risk and enable informed decision-making regarding public health and wildlife management.

Baylisascaris procyonis infection in raccoons: A review of demographic and environmental factors influencing parasite carriage

Baylisascaris procyonis, the roundworm of raccoons (Procyon lotor), is an emerging helminthic zoonosis in North America. Since the larval form is capable of causing neurological disease in more than 150 species of birds and mammals including humans, understanding factors that influence carriage of the parasite by raccoons is important for mitigating risk. This review examines the current literature to identify major demographic and environmental risk factors associated with B. procyonis carriage in wild raccoons. Raccoon age and season of sample collection were most commonly identified as risk factors, with increased prevalence found in juvenile animals and when sample collection occurred in the fall. Human urbanization and agricultural land use were also observed as potential risk factors; however, there are inconsistencies in the direction of influence these risk factors have on the prevalence of infection. Further investigation into the role of environmental risk factors is required to better understand how human activities influence parasite carriage in raccoons. Additionally, future research using multivariable statistical models guided by epidemiological principles to control for confounding variables and identify interaction effects will help clarify the effect of these demographic and environmental factors. Developing a better understanding of the primary risk factors for parasite carriage in raccoons will help identify areas of higher risk for environmental contamination and will aid in the development and refinement of education and management programs to reduce the risk of human exposure.

Survey of Baylisascaris spp. in Eastern Tennessee Wildlife and Detection of Baylisascaris spp. Eggs in Virginia Opossum ( Didelphis virginiana) Feces

We analyzed 69 eastern Tennessee wildlife samples for Baylisascaris spp. during 2011. The prevalence of Baylisascaris spp. in raccoons ( Procyon lotor) was 16% (8/49), an increase compared to previous surveys in this region. One Virginia opossum ( Didelphis virginiana) had eggs in its feces, indicating that opossums can play a role in Baylisascaris spp. transmission.

Raccoon roundworm (Baylisascaris procyonis) as an occupational hazard: 1. Knowledge of B. procyonis and attitudes towards it and other zoonoses among wildlife rehabilitators

Wildlife rehabilitators are at risk of zoonotic diseases because they often have prolonged contact with many species of wildlife and their bodily fluids. Raccoon roundworm (Baylisascaris procyonis) is a common zoonotic parasite of raccoons that has the potential to cause severe or fatal neurologic disease in a broad variety of hosts if the eggs within raccoon faeces are ingested. We administered an online survey to wildlife rehabilitators to assess their knowledge regarding aspects of transmission, biology and disease caused by B. procyonis, and also to evaluate attitudes towards wildlife diseases and B. procyonis as an occupational hazard. Knowledge was assessed using multiple choice and true-false questions; attitudes were measured using Likert-type items. A total of 659 complete or near-complete responses (missing fewer than three knowledge or attitudes items and/or non-response to some demographic fields) were collected. The median knowledge score was 7/14 questions correct (range: 0-14 correct). Generally, individuals with higher levels of education and rehabilitation experience, veterinary professionals and those who are members of professional wildlife rehabilitation groups scored above the median significantly more often (p < .01). Significantly more rehabilitators who were located in the south-east and those with part-time or infrequent commitments scored below the median overall knowledge score. There was general agreement that B. procyonis is a health risk of rehabilitators and that measures should be taken to control transmission to people and animals. Some factors explaining differences in attitudes include setting of rehabilitation (home versus animal care facility), veterinary profession, region, membership in a wildlife rehabilitation group and rehabilitation of raccoons. Findings emphasize the importance of awareness and mentorship to inform rehabilitators on the potential risks of B. procyonis and other potential zoonoses within captive wildlife settings, and the important role of professional wildlife rehabilitator groups in disseminating educational materials.

Similar yet different: co-analysis of the genetic diversity and structure of an invasive nematode parasite and its invasive mammalian host

Animal parasitic nematodes can cause serious diseases and their emergence in new areas can be an issue of major concern for biodiversity conservation and human health. Their ability to adapt to new environments and hosts is likely to be affected by their degree of genetic diversity, with gene flow between distinct populations counteracting genetic drift and increasing effective population size. The raccoon roundworm (Baylisascaris procyonis), a gastrointestinal parasite of the raccoon (Procyon lotor), has increased its global geographic range after being translocated with its host. The raccoon has been introduced multiple times to Germany, but not all its populations are infected with the parasite. While fewer introduced individuals may have led to reduced diversity in the parasite, admixture between different founder populations may have counteracted genetic drift and bottlenecks. Here, we analyse the population genetic structure of the roundworm and its raccoon host at the intersection of distinct raccoon populations infected with B. procyonis. We found evidence for two parasite clusters resulting from independent introductions. Both clusters exhibited an extremely low genetic diversity, suggesting small founding populations subjected to inbreeding and genetic drift with no, or very limited, genetic influx from population admixture. Comparison of the population genetic structures of both host and parasite suggested that the parasite spread to an uninfected raccoon founder population. On the other hand, an almost perfect match between cluster boundaries also suggested that the population genetic structure of B. procyonis has remained stable since its introduction, mirroring that of its raccoon host.

Baylisascaris procyonis roundworm infection patterns in raccoons (Procyon lotor) from Missouri and Arkansas, USA

Baylisascaris procyonis is a helminth parasite of raccoons Procyon lotor and represents a health concern in paratenic hosts, including humans and diverse domestic and wildlife species. In North America the helminth is expanding its geographic range. To better understand patterns of infection in the Ozark region of the USA, raccoons (n = 61) were collected in 2013-2014 from five counties in Missouri and Arkansas, USA and necropsied. We documented B. procyonis in all surveyed locations. The overall prevalence of B. procyonis was 44.3 % (95 % CI = 31.9 - 57.4) and was significantly higher in females than males. There were also significant differences in prevalence among raccoons sampled north and south of the Missouri River. Mean intensity was 9.9 (CI = 5.44 - 17.22), and parasites were highly aggregated among hosts such that approximately 20 % of hosts harbor 90 % of parasites. These levels of parasitism indicate that B. procyonis is common in the region and its impacts on paratenic hosts could be qualitatively similar to effects observed in other localities.

Update on Baylisascariasis, a Highly Pathogenic Zoonotic Infection

Baylisascaris procyonis, the raccoon roundworm, infects a wide range of vertebrate animals, including humans, in which it causes a particularly severe type of larva migrans. It is an important cause of severe neurologic disease (neural larva migrans [NLM]) but also causes ocular disease (OLM; diffuse unilateral subacute neuroretinitis [DUSN]), visceral larva migrans (VLM), and covert/asymptomatic infections. B. procyonis is common and widespread in raccoons, and there is increasing recognition of human disease, making a clinical consideration of baylisascariasis important. This review provides an update for this disease, especially its clinical relevance and diagnosis, and summarizes the clinical cases of human NLM and VLM known to date. Most diagnosed patients have been young children less than 2 years of age, although the number of older patients diagnosed in recent years has been increasing. The recent development of recombinant antigen-based serodiagnostic assays has aided greatly in the early diagnosis of this infection. Patients recovering with fewer severe sequelae have been reported in recent years, reinforcing the current recommendation that early treatment with albendazole and corticosteroids should be initiated at the earliest suspicion of baylisascariasis. Considering the seriousness of this zoonotic infection, greater public and medical awareness is critical for the prevention and early treatment of human cases.

The Increase of Exotic Zoonotic Helminth Infections: The Impact of Urbanization, Climate Change and Globalization

Zoonotic parasitic diseases are increasingly impacting human populations due to the effects of globalization, urbanization and climate change. Here we review the recent literature on the most important helminth zoonoses, including reports of incidence and prevalence. We discuss those helminth diseases which are increasing in endemic areas and consider their geographical spread into new regions within the framework of globalization, urbanization and climate change to determine the effect these variables are having on disease incidence, transmission and the associated challenges presented for public health initiatives, including control and elimination.

Reduction of Baylisascaris procyonis eggs in raccoon latrines, suburban Chicago, Illinois, USA

Baylisascaris procyonis, a common roundworm of raccoons, causes severe or fatal human infections, often in suburban areas. To evaluate the effectiveness of a baiting strategy requiring minimal labor, we distributed medicated baits near raccoon latrines in suburban Chicago, Illinois, USA. This strategy lowered B. procyonis prevalence in raccoons, possibly reducing risk to humans.

Survival, recruitment, and population growth rate of an important mesopredator: the northern raccoon

Populations of mesopredators (mid-sized mammalian carnivores) are expanding in size and range amid declining apex predator populations and ever-growing human presence, leading to significant ecological impacts. Despite their obvious importance, population dynamics have scarcely been studied for most mesopredator species. Information on basic population parameters and processes under a range of conditions is necessary for managing these species. Here we investigate survival, recruitment, and population growth rate of a widely distributed and abundant mesopredator, the northern raccoon (Procyon lotor), using Pradel's temporal symmetry models and >6 years of monthly capture-mark-recapture data collected in a protected area. Monthly apparent survival probability was higher for females (0.949, 95% CI = 0.936-0.960) than for males (0.908, 95% CI = 0.893-0.920), while monthly recruitment rate was higher for males (0.091, 95% CI = 0.078-0.106) than for females (0.054, 95% CI = 0.042-0.067). Finally, monthly realized population growth rate was 1.000 (95% CI = 0.996-1.004), indicating that our study population has reached a stable equilibrium in this relatively undisturbed habitat. There was little evidence for substantial temporal variation in population growth rate or its components. Our study is one of the first to quantify survival, recruitment, and realized population growth rate of raccoons using long-term data and rigorous statistical models.

Cerebral Baylisascaris larva migrans in a cynomolgus macaque (Macaca fascicularis)

An incidental, asymptomatic, focal inflammatory lesion was detected in brain cerebrum of an approximately 6-year-old, female cynomolgus macaque from a chronic toxicology study. No gross lesions were noted at necropsy. Microscopically, the lesion contained a cross-section of larvae approximately 70-80 μm in diameter, a centrally located intestine flanked on either side by large triangular excretory columns, and prominent single lateral cuticular alae. Mixed inflammatory cells of eosinophils, macrophages, and lymphocytes admixed with abundant connective tissue stroma and necrosis surrounded the larvae. Histochemical stains for trichrome revealed significant amount of fibrous connective tissue. The morphology of the larvae was compatible with Baylisascaris spp. Based on the microscopic and histochemical examination, a diagnosis of neural Baylisascaris spp. larva migrans was made.

Parasites and the conservation of small populations: The case of Baylisascaris procyonis

Human demands on natural resources result in landscape changes that facilitate the emergence of disease. Most emerging diseases are zoonotic, and some of these pathogens play a role in the decline of vulnerable wildlife species. Baylisascaris procyonis, the common roundworm parasite of raccoons (Procyon lotor), is a well recognized zoonotic infection that has many of the properties associated with a pathogen capable of driving extinction. It is highly non-specific and frequently pathogenic with regard to paratenic hosts, which contact eggs of B. procyonis at raccoon latrines. Eggs accumulate at latrines and remain viable for many years. Transmission of B. procyonis is sensitive to changes in land-use, and fragmented habitats increase contact rates between raccoons, potential paratenic hosts, and the parasite. Raccoons, and subsequently B. procyonis, have been introduced to Europe and Japan, where naïve vertebrates may be exposed to the parasite. Finally, domestic animals and exotic pets can carry patent infections with B. procyonis, thus increasing environmental contamination beyond raccoon latrines, and expanding the area of risk to potential paratenic hosts. This parasite can potentially contribute to extinctions of vulnerable species, as exemplified by the case of the Allegheny woodrat (Neotoma magister), a species that has experienced local declines and extinctions that are linked to B. procyonis. Conservation strategies for vulnerable species should consider the transmission ecology of parasitic pathogens, like B. procyonis.