Nodular Human Lagochilascariasis Lesion in Hunter, Brazil.

Lagochilascariasis is a rare helminthic infection caused by Lagochilascaris minor nematodes and found in Latin America; most cases are reported in the Amazon region. We report on a case observed in a hunter in southern Brazil and describe scanning electron microscopy results for L. minor adult forms.

Baylisascaris procyonis Central Nervous System Infection in a Four-Month-Old Gordon Setter Dog.

A 16 wk old intact female Gordon setter was examined for a 2 wk history of progressive cerebellovestibular ataxia. Eosinophilia was found on complete blood count, and the remaining blood work was normal. A trial treatment with clindamycin and anti-inflammatory prednisone did not result in improvement of clinical signs; therefore, the dog was euthanized. On histopathologic examination, cross sections of a 75 µm wide nematode larva with a 5 µm cuticle, prominent lateral cords, lateral alae, and coeloemyelian musculature were identified in a focally extensive region of cerebellar necrosis. The size and morphology of the parasites was most consistent with Baylisascaris procyonis. This case highlights a rare but important zoonotic disease that should be considered as a differential diagnosis in any dog exhibiting acute, progressive central nervous system signs, and peripheral eosinophilia. The index of suspicion should be elevated in dogs with an unknown deworming history and known or suspected exposure to raccoons. Because most anthelminthics have been shown to be effective against B. procyonis, annual deworming is recommended in the at-risk population to reduce the likelihood of aberrant migration and zoonosis.

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.

Rapid Therapeutic Response of Eosinophilic Meningoencephalitis in a Toddler With Baylisascaris procyonis Infection.

INTRODUCTION: Eosinophilic meningitis is an infrequently encountered condition. Baylisascaris procyonis (raccoon roundworm) infection, rarely diagnosed in North America, is a known cause of eosinophilic meningitis, often producing death or permanent neurologic damage. CASE REPORT: We recently encountered a toddler with geophagia and probable exposure to raccoon feces, who presented with eosinophilic meningitis and encephalitis, and was diagnosed with B procyonis infection and possible Toxocara co-infection. His marked peripheral eosinophilia and neurologic symptoms rapidly responded to corticosteroid and albendazole therapy. DISCUSSION: Since B procyonis infection is infrequently encountered, its diagnosis in the proper clinical and epidemiologic setting may not always be considered, resulting in a delay of appropriate therapy. Our patient, diagnosed and treated early in his course, demonstrated rapid clinical and laboratory improvement with anti-inflammatory and antiparasitic therapy. CONCLUSION: In cases of eosinophilic meningitis, infection with B procyonis should be routinely considered to allow timely institution of effective therapy for this unusual but potentially fatal or debilitating infection.

Characteristics of parasitic egg shedding over a 1-year period in foals and their dams in 2 farms in central Saskatchewan.

The goals of this study were to report the seasonal shedding patterns of strongyle and Parascaris spp. eggs in repeated fecal samples for mares (n = 38) and foals (n = 39), and to evaluate the efficacy of ivermectin treatment in mares from 2 selected horse breeding farms in central Saskatchewan. Median strongyle fecal egg counts (FEC) peaked in July and August in adult horses. The farms differed significantly (P = 0.0005) in regard to strongyle shedding categories (< 200; 200 to 500; and > 500 eggs/g) over time, but for each individual horse (both farms combined) these categories did not differ over time (P = 0.13) on samples collected in grazing season. When evaluating 3 samples collected fall, summer and fall in 2 consecutive grazing seasons, 94% of horses that shed < 200 eggs/g on 2 initial samples, remained in the same category on the third sample. Mares on each farm didn't differ statistically in shedding categories when comparing September samples from 2 consecutive years (Farm A: P = 0.56, Farm B: P = 0.06). Peak strongyle shedding occurred late fall in the first year of life for foals on Farm A, and in July in the second year of life for foals on Farm B. Parascaris spp. FEC were greatest in foals ≤ 6 months of age, with peak observed when foals were 5 to 6 months old. Ivermectin was 100% effective at reducing strongyle FEC 2 weeks after treatment in adult horses. Horses in Saskatchewan had relatively high strongyle shedding levels, which were significantly different between the farms, and high prevalence of Oxyuris equi. Strongyle shedding consistency was observed for FECs collected from mares in grazing season (July to September).

Caractéristiques de l'excrétion des oeufs de parasites pendant une période de 1 an chez les poulains et leurs mères dans deux fermes du centre de la Saskatchewan. Cette étude avait pour but de dresser un rapport sur les tendances d'excrétion saisonnière des oeufs des strongyles et de Parascaris spp. dans des prélèvements fécaux répétés pour les juments (n = 38) et les poulains (n = 39) et d'évaluer l'efficacité du traitement à l'ivermectine chez deux juments provenant de deux fermes d'élevage de chevaux dans le centre de la Saskatchewan. Les comptes médians d'oeufs fécaux des strongyles ont culminé en juillet et en août chez les chevaux adultes. Les fermes présentaient des différences significatives (P = 0,0005) à l'égard des catégories d'excrétion des strongyles (< 200; de 200 à 500; et > 500 oeufs/g) dans le temps, mais, pour chaque cheval individuel (les deux fermes combinées), ces catégories ne présentaient pas de différences à la longue (P = 0,13) pour les échantillons prélevés durant la saison de pâturage. Lors de l'évaluation des reois échantillons prélevés à l'automne, à l'été et à l'automne pendant deux saisons de pâturage consécutives, 94 % des chevaux qui avaient excrété < 200 oeufs/g pour deux prélèvements initiaux, sont demeurés dans la même catégorie pour le troisième échantillon. Les juments de chaque ferme ne présentaient pas de différences statistiques pour les catégories d'excrétion lorsque l'on comparait les échantillons de septembre provenant de deux années consécutives (Ferme A : P = 0,56, Ferme B : P = 0,06). L'excrétion des strongyles a culminé à la fin de l'automne pendant la première année de vie pour les poulains de la Ferme A et en juillet de la deuxième année de vie pour les poulains de la Ferme B. Les comptes d'oeufs fécaux de Parascaris spp. étaient les plus importants chez les poulains âgés de ≤ 6 mois et le point culminant était observé lorsque les poulains étaient âgés de 5 ou 6 mois. L'ivermectine était efficace à 100 % pour réduire les comptes d'oeufs fécaux 2 semaines après le traitement chez les chevaux adultes. Les chevaux de la Saskatchewan ont présenté des taux d'excrétion relativement élevés de strongyles, qui étaient significativement différents entre les fermes, et une forte prévalence d'Oxyuris equi. La constance de l'excrétion des strongyles a été observée pour les comptes d'oeufs fécaux obtenus auprès des juments pendant la saison de pâturage (de juillet à septembre).(Traduit par Isabelle Vallières).

Baylisascaris procyonis-Associated Meningoencephalitis in a Previously Healthy Adult, California, USA.

After severe neurocognitive decline developed in an otherwise healthy 63-year-old man, brain magnetic resonance imaging showed eosinophilic meningoencephalitis and enhancing lesions. The patient tested positive for antibodies to Baylisascaris spp. roundworms, was treated with albendazole and dexamethasone, and showed improvement after 3 months. Baylisascariasis should be considered for all patients with eosinophilic meningitis.

Baylisascaris Procyonis Exposure Case Study.

We report a case of exposure to raccoon feces found to be contaminated with baylisascaris procyonis. The exposure was recognized early enough by the family to allow prophylaxis with albendazole. Because of the potential fatal or neurologically catastrophic effects of this disease immediate treatment is indicated. This is started in advance of environmental studies that are done to determine if the feces is indeed contaminated.

Anthelmintic resistance of intestinal nematodes to ivermectin and pyrantel in Estonian horses.

There is evidence of resistance in horses to anthelmintic treatment using ivermectin and pyrantel. However, little information is available about the parasites, treatment practices or anthelmintic resistance in the horse population in Estonia. In the present study, we examined 41 trotting and riding horses aged < 3 years from four stables in Estonia. Faecal samples were collected, and horses were selected for treatment if the nematode egg count per gram faeces exceeded 200. Horses (n= 32) that shed strongyle-type eggs were treated with pyrantel, whereas Parascaris equorum-positive animals received ivermectin. Up to 78% of horses required anthelmintic treatment and the efficiency of the anthelmintics was evaluated using a faecal egg count reduction test. Resistance of P. equorum was observed in 50% of horses treated with ivermectin and of strongyles in 27% of horses treated with pyrantel. Ivermectin treatment resulted in a mean reduction of 100% for strongyle eggs and an 89% reduction in P. equorum, and pyrantel-treated horses exhibited an 88% reduction in strongyle eggs. These results are considered to be the first indication of resistance to pyrantel, but further studies of ivermectin resistance are required. According to questionnaires completed by the owners of horses, resistance might be explained by a lack of evidence-based strategies, a strong preference for using ivermectin and possibly a subjective evaluation of the body weight of horses.

Occurrence of fenbendazole resistance in Parascaris spp. on breeding farms in Sweden.

Anthelmintic resistance is an increasing problem in many gastrointestinal parasites of grazing animals. Among these, the equine roundworm, Parascaris spp., has developed wide-spread resistance to macrocyclic lactones over the past decades. Additionally, there are recent observations of emerging treatment failure of both tetrahydropyrimidine and fenbendazole. Therefore, the aims of this study were to further investigate the occurrence of fenbendazole resistance on breeding farms and to explore potential management-related risk factors associated with resistance in Parascaris spp. in Sweden. Eleven farms with 92 foals positive for Parascaris spp. were included in a faecal egg count reduction test during the years 2021-2023. According to the clinical protocol of the guidelines of the World Association for the Advancement of Veterinary Parasitology, fenbendazole resistance was present on four farms with efficacies varying from 45 % to 96 %. Having previously reported reduced efficacy on one of these farms, we can now confirm that fenbendazole resistance in Parascaris spp. has established. Farms with more than 40 yearly born foals had a significantly higher probability of having resistant Parascaris spp. Populations compared with smaller farms, (generalized linear model (GLM), t = 70.39, p < 0.001). In addition, there was a correlation between the number of foals on the farm and the frequency of yearly treatments showing that farms with < 20 foals were notably inclined to administer treatments twice during the first year (GLM, t=2.76, p < 0.05) in contrast to larger farms with > 40 foals that were using more frequent treatment intervals. In conclusion, this study confirms the establishment of fenbendazole resistance in Parascaris spp. populations on Swedish stud farms with the number of foals on the farm identified as a risk factor for development of anthelmintic resistance.

Further evaluation in field tests of the activity of three anthelmintics (fenbendazole, oxibendazole, and pyrantel pamoate) against the ascarid Parascaris equorum in horse foals on eight farms in Central Kentucky (2009-2010).

The activity of three anthelmintics (fenbendazole-FBZ; oxibendazole-OBZ; and pyrantel pamoate-PRT) was ascertained against the ascarid Parascaris equorum in horse foals on eight farms in Central Kentucky (2009-2010) in field tests. A total of 316 foals were treated, and 168 (53.2%) were passing ascarid eggs on the day of treatment. Evaluation of drug efficacy was determined qualitatively by comparing the number of foals passing ascarid eggs in their feces before and after treatment. The main purpose was to obtain data on current activity of these compounds against ascarids. Additionally, the objective was to compare these findings with those from earlier data on the efficacy of these three compounds on nematodes in foals in this geographical area. Efficacies (average) for the foals ranged for FBZ (10 mg/kg) from 50% to 100% (80%), for OBZ (10 mg/kg) from 75% to 100% (97%), and for PRT at 1× (6.6 mg base/kg) from 0% to 71% (2%) and at 2× (13.2 mg base/kg) 0% to 0% (0%). Although the efficacy varied among the drugs, combined data for all farms indicated a significant reduction of ascarid infections for FBZ (p < 0.0001) and OBZ (p < 0.0001) but not for PRT (p = 0.0953).

Comparative efficacy of ivermectin and levamisole for reduction of migrating and encapsulated larvae of Baylisascaris transfuga in mice.

The comparative efficacy of 2 anthelmintics (ivermectin and levamisole) against Baylisascaris transfuga migrating and encapsulated larvae was studied in mice. A total of 60 BALB/c mice inoculated each with about 1,000 embryonated B. transfuga eggs were equally divided into 6 groups (A-F) randomly. Mice of groups A and B were treated with ivermectin and levamisole, respectively, on day 3 post-infection (PI). Mice of groups A-C were killed on day 13 PI. Similarly, groups D and E were treated with ivermectin and levamisole, respectively, on day 14 PI, and all mice of groups D-F were treated on day 24 PI. The groups C and F were controls. Microexamination was conducted to count the larvae recovering from each mouse. The percentages of reduction in the number of migrating larvae recovered from group A (ivermectin) and B (levamisole) were 88.3% and 81.1%, respectively. In addition, the reduction in encapsulated larvae counts achieved by ivermectin (group D) and levamisole (group E) was 75.0% and 49.2%, respectively. The results suggested that, to a certain extent, both anthelmintics appeared to be more effective against migrating larvae than encapsulated larvae. However, in the incipient stage of infection, ivermectin may be more competent than levamisole as a larvicidal drug for B. transfuga.

First Report of Resistance to Ivermectin in Parascaris univalens in Iceland.

Horses in Iceland have been isolated for more than 1,000 yr but still harbor a similar range of gastrointestinal parasites as do horses across the world. The long isolation of the horses and their parasites presumably means that no resistance genes have been introduced into the Parascaris spp. population. It is therefore of particular interest to investigate the efficacy of ivermectin on Parascaris spp. infecting Icelandic foals. Potential treatment failure of ivermectin in Iceland will add substantial new information on how resistance can arise independently. This study aimed to determine the efficacy of subcutaneous injection of ivermectin for the treatment of Parascaris spp. infection in foals and to identify the Parascaris species present in the west and north of Iceland. A fecal egg count reduction (FECR) test (FECRT) was performed on 50 foals from 8 farms, including an untreated control group of 6 foals, from September to November 2019. The foals were between 3 and 5 mo of age at the start of the study and had not previously been treated with anthelmintic drugs. Each foal was treated subcutaneously with off-label use of Ivomec® injection 10 mg/ml or Noromectin® 1% at a dose of 0.2 mg/kg. The FECR for each farm was calculated in 2 ways, by the eggCounts package in R and by the Presidente formula (FECRT). Both calculation methods resulted in efficacy levels between 0% and 80.78%, indicating ivermectin resistance on all farms. We also confirmed, by karyotyping, that the species of equine ascarid present in the west and north of Iceland is Parascaris univalens. This study provides evidence for treatment failure of ivermectin against P. univalens infection in foals. Since Icelandic horses have been isolated on the island for more than 1,000 yr, this implies that resistance alleles have developed independently in the Icelandic Parascaris population. The actual clinical impact of ivermectin resistance is unknown but another drug of choice should be considered to treat Parascaris infection in foals in Iceland.

Reduced efficacy of ivermectin and moxidectin against Parascaris spp. in foals from Argentina.

Macrocyclic lactones are the most widely used drugs for the control of gastrointestinal nematodes of horses in Argentina. Ivermectin and moxidectin are used as broad spectrum anthelmintics and although there are several international reports on the resistance of Parascaris spp., the resistance status of the local nematode population is largely unknow. This report informs a case of suboptimal efficacy to both drugs to control Parascaris spp in foals in central Argentina. In February 2018, routine fecal parasite egg counts showed a moderate-high number of Parascaris spp eggs (mean = 680 eggs per gram of feces) in foals treated approximately one month before with moxidectin. Upon suspicion of resistance of this parasite to the macrocyclic lactones, 24 of these animals were selected for a fecal egg count reduction test (FECRT). Twelve foals were treated with ivermectin and the remaining 12 animals with moxidectin. Two weeks after treatment, the FECRT was 48.1% and 34.8% for moxidectin and ivermectin respectively (25% of the animals increased the number of eggs in feces after treatment). Five days later, the administration of fenbendazole resulted in a FECRT = 100%. The monitoring of the status of susceptibility or resistance in each establishment is critical for the design of control programs based on rational and sustainable use of anthelmintics.

Lagochilascaris minor (Nematoda, Ascarididae) in a domestic cat in a coastal city of the state of São Paulo.

This paper describes the discovery of Lagochilascaris minor parasitizing a stray cat (Felis catus) in São Sebastião, a coastal city in the state of São Paulo, Brazil. The cat presented fistulas with purulent secretion in the ventral cervical region. A thorough evaluation revealed nematodes in the site. The parasites were removed, amounting to a total of about 100 specimens. The parasite species was identified based on measurements and morphological characteristics of adult worms. This report of parasitism by L. minor in domestic cats in the state of São Paulo reinforces the need for greater attention to this parasitosis, given the increase in cases among carnivores in Brazil.

Unusual case of lagochilascariasis with breast involvement: the first case report in pregnancy.

Lagochilascariasis is a neglected neotropical helminthiasis, responsible for human infections through the ingestion of raw or undercooked meat from wild animals infected by larvae encysted in their tissues. It is characterized by a chronic evolution with periods of remission and recurrences, affecting mainly the head and neck regions. It can progress to death by invasion of the central nervous system. It is caused by the Lagochilascaris minor nematode, first described in 1909 and mainly found in the Brazilian Amazon ecosystem, notably in Para State. In May 2010, a 15-year-old female, born in the city of Aveiro, Para State, was hospitalized in the city of Santarem, Para State, presenting with cervical and spinal abscesses and osteolytic lesions at T3-T5 level. During hospitalization, white larvae identified as L. minor were observed in a cervical subcutaneous fistula. After the surgical drainage of abscesses, albendazole 400 mg/day was started, with improvement of symptoms. The patient abandoned the follow-up and in January 2016, during the 20th week of pregnancy, she was readmitted to the Santarem Municipal Hospital with new cervical abscesses in the infra-mammary region, with numerous larvae exiting by subcutaneous left breast fistulas. The antiparasitic treatment was restarted due to possible reactivation of the infection in the spine and dissemination to the central nervous system. Ten weeks after hospital discharge, the patient had resolution of the fistulas and decreased abscesses, without gestational complications. This is the first case report of lagochilascariasis during pregnancy, as well as of involvement of mammary glands.

Efficacy of a new oral chewable tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio™) against induced ascarid infections in dogs.

BACKGROUND: Ascarid infections are among the most prevalent intestinal parasitic infections occurring in dogs around the world, with Toxocara canis and Toxascaris leonina commonly observed. Toxocara canis can cause considerable disease in dogs and humans, and year-round prophylactic treatment and control in dogs is recommended. Elimination of immature stages of these parasites before egg-laying will reduce environmental contamination and the risk of infection for both dogs and humans. Studies were conducted to evaluate the efficacy of a novel, oral chewable tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio™) against induced immature adult (L5) and adult T. canis, and adult T. leonina infections in dogs. METHODS: Six negative-controlled, masked, randomized laboratory studies were conducted. Two studies each evaluated efficacy against immature adult (L5) T. canis, adult T. canis, and adult T. leonina. Sixteen to 40 dogs were included in each study. Dogs experimentally infected with the target parasite were dosed once on Day 0 with either placebo tablets or Simparica Trio™ tablets to provide minimum dosages of 1.2 mg/kg sarolaner, 24 µg/kg moxidectin and 5.0 mg/kg pyrantel (as pamoate salt). Efficacy was based on the number of worms recovered at necropsy 7-10 days after treatment compared to placebo control. RESULTS: Based on geometric mean worm counts, efficacy of the sarolaner + moxidectin + pyrantel combination was ≥ 95.2% against immature adult T. canis, ≥ 97.3% against adult T. canis, and ≥ 89.7% against adult T. leonina. There were no treatment-related adverse events in any study. CONCLUSIONS: These studies confirm the efficacy of a single dose of a new oral chewable tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio™) against immature adult and adult T. canis, and adult T. leonina infections in dogs.

The P-glycoprotein repertoire of the equine parasitic nematode Parascaris univalens.

P-glycoproteins (Pgp) have been proposed as contributors to the widespread macrocyclic lactone (ML) resistance in several nematode species including a major pathogen of foals, Parascaris univalens. Using new and available RNA-seq data, ten different genomic loci encoding Pgps were identified and characterized by transcriptome-guided RT-PCRs and Sanger sequencing. Phylogenetic analysis revealed an ascarid-specific Pgp lineage, Pgp-18, as well as two paralogues of Pgp-11 and Pgp-16. Comparative gene expression analyses in P. univalens and Caenorhabditis elegans show that the intestine is the major site of expression but individual gene expression patterns were not conserved between the two nematodes. In P. univalens, PunPgp-9, PunPgp-11.1 and PunPgp-16.2 consistently exhibited the highest expression level in two independent transcriptome data sets. Using RNA-Seq, no significant upregulation of any Pgp was detected following in vitro incubation of adult P. univalens with ivermectin suggesting that drug-induced upregulation is not the mechanism of Pgp-mediated ML resistance. Expression and functional analyses of PunPgp-2 and PunPgp-9 in Saccharomyces cerevisiae provide evidence for an interaction with ketoconazole and ivermectin, but not thiabendazole. Overall, this study established reliable reference gene models with significantly improved annotation for the P. univalens Pgp repertoire and provides a foundation for a better understanding of Pgp-mediated anthelmintic resistance.

Field effectiveness of pyrantel and failure of Parascaris equorum egg count reduction following ivermectin treatment in Italian horse farms.

A study was carried out to assess the field efficacy of ivermectin (IVM) and pyrantel pamoate (PYR) against Parascaris equorum. Seventy-three foals (3-18 months old) from 5 stud farms, not treated with anthelmintics in the previous 10 weeks and with individual faecal egg counts (FEC) >200, were included in the study. For each stud farm, 5-7 foals were included in the IVM-treatment group (IVM 0.2%, 200 mcg/kg body weight) or in the PYR-treatment group (PYR 38%, 13.2mg/kg body weight) and 3 were untreated as controls. For each foal, FECs were carried out before treatment (Day 0) and on Days 7 and 21. An individually based estimation of efficacy was assessed by a bootstrap simulation applied to different previously suggested formulae to evaluate the percent reduction of faecal egg counts (FECR). Two thousand bootstrap resamples were constructed from individual FECRs and the parasite population was considered susceptible for FECs >or=90 and 95% confidence interval (C.I.) >or=95%, suspected resistant for FECRs comprised between 80 and 90% and 95% C.I. <95% and resistant when FECR