Spread of the Zoonotic Nematode Baylisascaris procyonis into a Naive Raccoon Population.

The raccoon roundworm (Baylisascaris procyonis), a gastrointestinal nematode of the raccoon (Procyon lotor), may cause a severe form of larva migrans in humans, which can lead to death or permanent neurological damage. Although roundworms were inadvertently introduced to Europe alongside their raccoon hosts, the parasite is not present in every raccoon population. It is important to understand the geographic distribution of B. procyonis, as early and rapid treatment can prevent severe pathologies in humans. We present evidence for the roundworm spreading into a naive raccoon population through natural dispersal of infected raccoons. We sampled 181 raccoons from Saxony-Anhalt, a German federal state containing contact zones of different raccoon populations, two of which were previously free of the parasite. We screened the raccoons for roundworms and used microsatellite-based assignment tests to determine the genetic origin of the raccoons and their parasites. We detected roundworms in 16 of 45 raccoons sampled in a previously roundworm-free area in the northern part of the state. The largest proportion of the genetic ancestry (≥ 0.5) of the 16 raccoon hosts was assigned to the previously naive raccoon population. Conversely, the genetic ancestry of almost all the roundworms was assigned to the nearest roundworm population in the southern part of the state. Infected raccoons have, therefore, spread to the north of the state, where they interbred with and infected local raccoons. It seems likely that the roundworms will continue to spread. Health authorities should consider continuous surveillance programmes of naive populations and raise public awareness.

Infection levels of Gnathostomatidae (Nematoda) larvae in commercial fishes in north-eastern Australian waters and related food safety concerns.

The majority of research on the safety of marine edible fish has primarily focused on anisakid nematodes, neglecting the potential risks posed by other parasites, including those belonging to the family Gnathostomatidae. In Australia, there have been few reported cases of human infections with gnathostomatid parasites since 2011. However, due to the absence of a standardized diagnostic test in the country, it is believed that the actual number of infections is higher than reported. This study aimed to assess the occurrence and prevalence of infectious gnathostomatid parasites in selected commercial fish species in Australia. A total of 1947 marine fish from northern Australia, representing 9 families, 16 genera, and 30 species, were examined for gnathostomatid nematode infections. Overall, 12.3 % of the fish were found to be infected with at least one gnathostomatid larva. Among the species examined, the yellow-dabbled flounder (Branchypleura novaezeelandiae) exhibited the highest prevalence (83.3 %; n = 6) and the largest number of gnathostomatid larvae. The identification of the gnathostomatid larvae was confirmed as belonging to the genus Echinocephalus based on both morphological characteristics and sequence data. No significant correlation was observed between the prevalence, mean abundance, and mean intensity of infection with the length or weight of the examined fish species. Notably, several of the infected fish species are considered popular choices in the Australian market. Hence, it is imperative to raise awareness among relevant food safety authorities regarding the occurrence of these parasites. The findings from this study should be taken into consideration for the revision of current seafood safety protocols in the country.

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.

Distribution of Baylisascaris procyonis in Raccoons (Procyon lotor) in Florida, USA.

Baylisascaris procyonis, or raccoon roundworm, is an intestinal nematode parasite of raccoons (Procyon lotor) that is important to public and wildlife health. Historically, the parasite was uncommon in the southeastern US; however, the range of B. procyonis has expanded to include Florida, US. From 2010 to 2016, we opportunistically sampled 1,030 raccoons statewide. The overall prevalence was 3.7% (95% confidence interval=2.5-4.8%) of sampled individuals, and infection intensity ranged from 1 to 48 (mean±standard deviation 9.9±4.0). We found raccoon roundworm in 9/56 (16%) counties sampled, and the percent positive ranged from 1.1% to 13.3% of specimens collected per county. Including previously published data, B. procyonis was detected in 11 Florida counties. We used logistic regression to estimate the contribution of raccoon demographic variables and the presence of the endoparasite Macracanthorhynchus ingens to B. procyonis detection in Florida. Following the model selection process we found housing density, M. ingens presence, and urbanicity to be predictive of raccoon roundworm presence. We also found substantial among-county variation. Raccoon sex and age were not useful predictors. Public health officials, wildlife rehabilitators, wildlife managers, and others should consider any Florida raccoon to be potentially infected with B. procyonis, particularly in areas where housing density is high.

Microsatellite profiling of hosts from parasite-extracted DNA illustrated with raccoons (Procyon lotor) and their Baylisascaris procyonis roundworms.

BACKGROUND: Important information on movement pathways and introduction routes of invasive parasites can be obtained by comparing the genetic makeup of an invader with its spatial genetic structure in other distribution areas. Sometimes, the population genetic structure of the host might be more informative than that of the parasite itself, and it is important to collect tissue samples of both host and parasite. However, host tissue samples are frequently not available for analysis. We aimed to test whether it is possible to generate reliable microsatellite profiles of host individuals by amplifying DNA extracted from a nematode parasite, using the raccoon (Procyon lotor) and the raccoon roundworm (Baylisascaris procyonis) as a test case. METHODS: Between 2020 and 2021, we collected tissue as well as a single roundworm each from 12 raccoons from central Germany. Both the raccoon and the roundworm DNA extracts were genotyped using 17 raccoon-specific microsatellite loci. For each roundworm DNA extract, we performed at least eight amplification reactions per microsatellite locus. RESULTS: We extracted amplifiable raccoon DNA from all 12 roundworms. We obtained at least two amplification products for 186 of the 204 possible genotypes. Altogether 1077 of the 1106 genotypes (97.4%) matched the host-DNA derived reference genotypes and thus did not contain genotyping errors. Nine of the 12 roundworm-derived genetic profiles matched the reference profiles from the raccoon hosts, with one additional genetic profile containing genotyping errors at a single locus. The remaining two genetic profiles were deemed unsuitable for downstream analysis because of genotyping errors and/or a high proportion of missing data. CONCLUSIONS: We showed that reliable microsatellite-based genetic profiles of host individuals can be obtained by amplifying DNA extracted from a parasitic nematode. Specifically, the approach can be applied to reconstruct invasion pathways of roundworms when samples of the raccoon hosts are lacking. Further research should assess whether this method can be replicated in smaller species of parasitic nematodes and other phyla of parasites more generally.

Epidemiological study on factors influencing the occurrence of helminth eggs in horses in Germany based on sent-in diagnostic samples.

Gastrointestinal nematodes are ubiquitous parasites of grazing equines with Parascaris spp., and strongyles being the most relevant ones regarding the prevalence and potential disease severity. Despite their importance, epidemiological data regarding the presence and egg-shedding intensities of these parasites are scarce. Data from 1067 horse samples collected on German horse farms initially to compare diagnostic methods were used for epidemiological analyses. Due to its higher sensitivity, presence/absence data were based on a combined sedimentation/flotation technique while faecal egg counts were based on Mini-FLOTAC. For strongyles, 46.5% of the samples were positive and the median egg-shedding intensity was 40 (range 5-2590). In multivariate analyses, prevalence and egg-shedding intensity were significantly influenced by season, age group and sample type. The drug used for the last treatment and the number of foals on the yard only affected prevalence while the number of horses on the yard and sex were only significant for egg-shedding intensity. For Parascaris spp., a prevalence of 4.6% and a median egg-shedding intensity of 0 (range 5-905) were observed. In multivariate analyses, the age group, the time since the last anthelmintic treatment, presence and number of foals had significant effects on ascarid prevalence whereas egg-shedding intensity was significantly influenced by age group and season only. Parascaris occurred only on yards with foals, but with an increasing number of foals, Parascaris egg-shedding intensity decreased. Prevalence and egg-shedding intensity were influenced by different but partially overlapping variables for Parascaris and strongyles.

First report of the zoonotic nematode Baylisascaris procyonis in non-native raccoons (Procyon lotor) from Italy.

Baylisascaris procyonis is a nematode parasite of the raccoon (Procyon lotor), and it can be responsible for a severe form of larva migrans in humans. This parasite has been reported from many countries all over the world, after translocation of its natural host outside its native geographic range, North America. In the period between January and August 2021, 21 raccoons were cage-trapped and euthanized in Tuscany (Central Italy), in the context of a plan aimed at eradicating a reproductive population of this non-native species. All the animals were submitted for necroscopic examination. Adult ascariids were found in the small intestine of seven raccoons (prevalence 33.3%). Parasites have been identified as B. procyonis based on both morphometric and molecular approaches. The aim of the present article is to report the first finding of this zoonotic parasite from Italy, highlighting the sanitary risks linked to the introduction of alien vertebrate species in new areas.

Population genetics, invasion pathways and public health risks of the raccoon and its roundworm Baylisascaris procyonis in northwestern Europe.

The geographic range of the zoonotic raccoon roundworm (Baylisascaris procyonis) is expanding together with the range of its host, the raccoon (Procyon lotor). This creates a new public health risk in parts of Europe where this parasite was previously absent. In the Netherlands, a raccoon population is becoming established and incidental findings of B. procyonis have been reported. To assess the risk to public health, the prevalence of B. procyonis was determined in the province of Limburg, where currently the largest Dutch raccoon population is present, as well as in the adjoining region of southern Belgium. Furthermore, genetic methods were employed to assess invasion pathways of both the raccoon and B. procyonis to aid in the development of control measures. Macroscopic analysis of intestinal content and testing of faecal samples were performed to detect B. procyonis adults and eggs. The population genetics of both B. procyonis and its raccoon host were analysed using samples from central and northwestern Europe. B. procyonis was found in 14/23 (61%, 95% CI: 41%-78%) raccoons from Limburg, but was not detected in 50 Belgian raccoons. Genetic analyses showed that the majority of the Dutch raccoons and their roundworms were introduced through ex-captive individuals. As long as free-living raccoon populations originate from captivity, population control methods may be pursued. However, natural dispersal from the border regions will complicate prolonged population control. To reduce the public health risk posed by B. procyonis, public education to increase awareness and adapt behaviour towards raccoons is key.

GEOGRAPHICAL VARIATION OF ENTEROPARASITISM IN THE SOUTHERN SEA LION OTARIA FLAVESCENS (SHAW, 1800) OFF THE COAST OF CHILE AS EVIDENCED WITH COPROLOGICAL TESTS: IMPLICATONS FOR ZOONOTIC RISKS.

The scarce information on the helminth fauna in otariids from the Southeastern Pacific comes mainly from stranded individuals or killed for that purpose. In this study, we compared the abundance and composition of enteroparasitic assemblages of Otaria flavescens using coprological techniques. Three sampling localities from north to south spanning 2,200 km off the Chilean coast were considered (Iquique, Viña del Mar, and Talcahuano). In all, 60 fecal samples were collected, and eggs belonging to 5 taxa were found in 91.6% of the samples. They were the anisakid nematodes Contracaecum and Pseudoterranova, the cestode Adenocephalus (syn. Diphyllobothrium), the trematode Ogmogaster, and the acanthocephalan Corynosoma. Samples from southern Chile (Talcahuano) showed the highest prevalence. Adenocephalus eggs had the highest prevalence and abundance in Iquique and Talcahuano, whereas Ogmogaster was the less prevalent and abundant in all sampling localities. Corynosoma eggs had similar prevalence and abundance among sampling localities, and Pseudoterranova eggs were absent in Iquique and with median prevalence values in Viña del Mar and Talcahuano. Thus, the composition of parasite egg assemblages was different between sampling localities. These differences between sampling localities may help to explain differential records of some zoonotic parasitoses such as pseudoterranovosis and diphyllobothriosis in Peru and Chile, where consumption of raw or marinated fish (ceviche) is common. For example, the lower diversity of parasite egg assemblages in the northern Chilean coast may be due to the absence or lower abundance of first intermediate/paratenic hosts of Pseudoterranova.

Parascaris spp. eggs in horses of Italy: a large-scale epidemiological analysis of the egg excretion and conditioning factors.

BACKGROUND: Equine ascariosis, caused by Parascaris spp., is a worldwide endoparasitic disease affecting young horses in particular. Despite the great number of horses reared in Italy, large-scale epidemiological surveys dealing with ascariosis prevalence in the country are not reported in the current literature. For this reason, the present survey aims to describe, for the first time, the spread and infestation of Parascaris spp. in a large population of Italian horses (6896 animals) using faecal egg counts, and further to identify risk factors associated with ascarid egg shedding. METHODS: Individual rectal faecal samples collected during routine veterinary examinations were used and Parascaris spp. prevalence was tested against the animal's age, sex, housing conditions, geographic provenance as well as the respective sampling season. RESULTS: Among the examined stables, 35.8% showed at least one horse to be positive for Parascaris spp. eggs and an overall prevalence of 6.3% was found. Ascariosis rates tended to decrease significantly with age and, proportionally, 80.0% of the recorded Parascaris spp. eggs were found in 0.7% of the examined animals. Statistically significant differences among prevalence rates were found between the different geographic areas of provenance and prevalence was found to be higher in horses reared outdoors compared to those raised indoors. Analysis of data based on sex and season did not show any significant differences. Despite the lower prevalence found compared to other European countries, ascariosis was concluded to represent a significant health challenge for horses reared in Italy, especially foals. Age (foals and yearlings) and outdoor rearing were identified to be significant risk factors for Parascaris spp. egg shedding. Furthermore, the relevance of the infected horses over 6 years of age should not be underestimated as these represent a significant source of contamination for younger animals. CONCLUSIONS: The development of improved treatment protocols based on regular faecal examination combined with follow-up assessment of the efficacy of integrated action plans would prove beneficial in regard to animal health and anthelmintic resistance reduction in the field.

PHYLOGEOGRAPHY OF BAYLISASCARIS PROCYONIS (RACCOON ROUNDWORM) IN NORTH AMERICA.

Sequences of the mitochondrial cytochrome c oxidase 1 (COI) gene of 115 Baylisascaris procyonis individuals from 13 U.S. states and 1 Canadian province were obtained from 44 raccoon hosts to assess genetic variation and geographic structure. The maximum genetic distance between individuals was low (1.6%), consistent with a single species. Moderate COI haplotype (h = 0.60) and nucleotide (π = 0.0053) diversity were found overall. Low haplotype diversity was found among samples east of the Mississippi River (h = 0.036), suggesting that historical growth and expansion of raccoon populations in this region could be responsible for high parasite gene flow or a selective sweep of B. procyonis mtDNA. There was low genetic structure (average Φst = 0.07) for samples east of the continental divide, but samples from Colorado showed higher diversity and differentiation from midwestern and eastern samples. There was marked genetic structure between samples from east and west of the continental divide, with no haplotypes shared between these regions. There was no significant isolation by distance among any of these geographic samples. The phylogeographic patterns for B. procyonis are similar to genetic results reported for their raccoon definitive hosts. The phylogeographic divergence of B. procyonis from east and west of the continental divide may involve vicariance resulting from Pleistocene glaciation and associated climate variation.

Identification and genetic characterization of Contracaecum sp. (Nematoda: Anisakidae) from China.

Contracaecum species are economically important fish-borne larval nematodes with zoonotic significance. In June 2019, more than 100 piscivorous birds died in their habitats close to the Wild Duck Lake, located in Yanqing, northwest of Beijing, China. Post-mortem examination of Black Night Herons (Nycticorax) revealed the presence of numerous anisakid nematodes in the proventriculus. Recovered nematodes were identified as Contracaecum sp. based on morphological description. Phylogenetic analysis of the mitochondrial (mt) genome and the ITS gene showed that sequences of Contracaecum sp. Beijing isolates were grouped into a new individual cluster. Furthermore, the parasite was successfully isolated from fresh dead birds, feces of piscivorous birds, and fish and prevalence ranged from 8.0% to 81.8%. Consequently, our study demonstrated Contracaecum sp. infections in different sources from China, which might constitute a threat to wildlife, aquaculture, and public health.

A potential zoonotic threat: First detection of Baylisascaris procyonis in a wild raccoon from Austria.

Baylisascaris procyonis is a common gastrointestinal parasite of raccoons (Procyon lotor) in their native range, and both have been introduced to Europe. Humans may ingest ascarid eggs shed via the racoons' faeces, and this could lead to severe infections affecting the central nervous system. Here, we report the first occurrence of B. procyonis in Austria. The parasite was detected in a two-year-old male raccoon that was road-killed in November 2019 near Hittisau (Vorarlberg). Genetic profiling provided strong evidence that the raccoon (and its parasite) originated from the nearest German raccoon population. The first finding in Austria highlights the need for monitoring the parasite and information of the public and practitioners.

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.

Infection and molecular identification of ascaridoid nematodes from the important marine food fish Japanese threadfin bream Nemipterus japonicus (Bloch) (Perciformes: Nemipteridae) in China.

The Japanese threadfin bream N. japonicus (Bloch) (Perciformes: Nemipteridae) is an important marine food fish in Asia. However, our present knowledge of the occurrence of its nematode parasites is still limited. In the present study, the species composition and infection rate of ascaridoid nematodes in N. japonicus from the South China Sea, were studied for the first time. Five ascaridoid species, namely Anisakis typica (L3), Hysterothylacium amoyense (L3), Hysterothylacium sp. IV-A (L3), adult of H. thalassini and Raphidascaris lophii (L3), were identified using integrative taxonomy. Hysterothylacium amoyense was the most prevalent species (prevalence 47.2%, mean intensity 14.9 ± 17.1). Hysterothylacium thalassini and R. lophii were reported in the Japanese threadfin bream for the first time. Two different genotypes of A. typica (overall prevalence of 3.4%; mean intensity 1.7 ± 0.9) were found in the South China Sea for the first time. The unique restriction polymorphism patterns of three species of Hysterothylacium are provided for rapid diagnosis. Our present results indicate that RFLP analysis of ITS region, using the restriction enzymes HhaI and RsaI, represents a simple and practical method for large-scale surveys of Hysterothylacium for seafood industry.

New insights into the coexistence of Contracaecum rudolphii A and Contracaecum rudolphii B (Nematoda: Anisakidae) in Phalacrocorax carbo sinensis from Sardinia: genetic variability and phylogenetic analysis.

Contracaecum sp. nematodes are important parasites of fish eating birds that can cause animal health problems. In the present study, specimens of Contracaecum rudolphii sensu lato, from the great cormorant Phalacrocorax carbo sinensis from Sardinia, were characterized based on morphological and molecular data. The morphological analysis allowed to identify all the fourth stage larvae (n = 1918) as Contracaecum sp., and adults, male (n = 5845) and female (n = 8312), as C. rudolphii sensu lato. Population genetics and phylogenetic relationships were inferred based on mitochondrial and nuclear markers. Multiple sequence alignment of the ribosomal internal transcribed spacer showed the coexistence of C. rudolphii A (n = 157), C. rudolphii B (n = 22) and a rare heterozygote of these species. Moreover, mitochondrial markers, namely NADH dehydrogenase subunits I (nad1), cytochrome c oxidase subunit (cox1 and cox2) and small subunit of rRNA (rrnS), showed that the studied C. rudolphii A populations had undergone bottleneck, or founder effect event, subsequent to a rapid population growth and expansion. The observed heterozygote is with a mitochondrial pattern of C. rudolphii B. Although, both Contracaecum species showed high genetic diversity, no genetic structure between localities was detected. Phylogenetic reconstructions supported the paraphyly of the avian Contracaecum species including C. ogmorhini (parasite of otariids).

Ascaridoids in commercial fish: Occurrence, intensity and localization in whole fish and fillets destined for the Belgian market.

Anisakidae and Raphidascaridae are marine nematodes present in a wide range of fish hosts, which may cause gastro-intestinal complaints and/or allergy in human, in addition to economic losses for the industry. Data regarding the presence of these parasites in fish for the Belgian market is currently missing; therefore, our aim was to investigate the presence and intensity of ascaridoids in a wide range of commercially fish species. A total of 415 fish samples, belonging to 36 different fish species, were collected from a Belgian whole-sale company. Ascaridoid larvae from the viscera (if present) and the muscles were collected by enzymatic digestion and the prevalence, median intensity, mean number of larvae per 100 g infected muscle, and localisation were determined. An overall prevalence of 53% [95%-CI: 42-63%] in the viscera and 27% [95%-CI: 23-32%] in the muscles was observed. Infection in the muscles varied between the fish species; no larvae were detected in 13 fish species, while a high prevalence (>78%) was observed in pollack, halibut, and gurnard. Most samples originated from the Northeast Atlantic Ocean, with the highest prevalence in the muscles observed in the Barents & Norwegian Sea (65% [95%-CI: 38-86]). Muscle samples were, if possible, divided in an anterior region, belly flap, medial region, and posterior region, with the most infections and larvae found in the belly flaps. In all samples, a total of 2569 larvae were recovered, with 1594 larvae originating from the viscera and 975 from the muscles; with an average of two larvae per 100 g infected fillet detected. Larvae were morphologically identified, and a subgroup was further confirmed using PCR/RFLP, resulting ultimately in the identification of Anisakis simplex s.s. (1853 larvae), A. pegreffii (137), A. simplex/pegreffii hybrid genotype (38), Pseudoterranova decipiens (160) and Hysterothylacium aduncum (380). This study demonstrates that ascaridoid larvae are highly prevalent in different fish species on the Belgian market.

Prevalence of Baylisascaris procyonis in raccoon latrines in southern Ontario, Canada.

Raccoon latrines represent sites of potential infection by the zoonotic parasite Baylisascaris procyonis for wildlife and humans. Our objective was to determine the prevalence of B. procyonis at raccoon latrine sites in southern Ontario. Thirty raccoon latrines were sampled between June - July 2018; multiple scats were collected and homogenized to form a representative sample of each latrine. To determine the presence or absence of B. procyonis eggs in each sample, we used the Cornell-Wisconsin centrifugal floatation technique. Twenty-three percent (7/30) of homogenized samples tested positive for B. procyonis. Eggs per gram of feces ranged from 1 to 388 (median = 1.28, IQR = 0.32-232.5). Baylisascaris procyonis positive latrines were found in conservation areas heavily used by people, which may represent a possible source of exposure for humans in these areas.

Geographic Distribution of Raccoon Roundworm, Baylisascaris procyonis, Germany and Luxembourg.

Infestation with Baylisascaris procyonis, a gastrointestinal nematode of the raccoon, can cause fatal disease in humans. We found that the parasite is widespread in central Germany and can pose a public health risk. The spread of B. procyonis roundworms into nematode-free raccoon populations needs to be monitored.

Compilation of 29 years of postmortem examinations identifies major shifts in equine parasite prevalence from 2000 onwards.

Horses are infected by a wide range of parasite species that form complex communities. Parasite control imposes significant constraints on parasite communities whose monitoring remains, however, difficult to track through time. Postmortem examination is a reliable method to quantify parasite communities. Here, we compiled 1,673 necropsy reports accumulated over 29 years, in the reference necropsy centre from Normandy (France). The burden of non-strongylid species was quantified and the presence of strongylid species was noted. Details of horse deworming history and the cause of death were registered. Building on these data, we investigated the temporal trend in non-strongylid epidemiology and we determined the contribution of parasites to the deaths of horses throughout the study period. Data analyses revealed the seasonal variations of non-strongylid parasite abundance and reduced worm burden in race horses. Beyond these observations, we found a shift in the species responsible for fatal parasitic infection from the year 2000 onward, whereby fatal cyathostominosis and Parascaris spp. infection have replaced cases of death caused by Strongylus vulgaris and tapeworms. A concomitant break in the temporal trend of parasite species prevalence was also found within a 10 year window (1998-2007) that has seen the rise of Parascaris spp. and the decline of both Gasterophilus spp. and tapeworms. A few cases of parasite persistence following deworming were identified, which all occurred after 2000. Altogether, these findings provide insights into major shifts in non-strongylid parasite prevalence and abundance over the last 29 years. They also underscore the critical importance of Parascaris spp. in young equids.