Larva Migrans In Humans Research Articles

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.

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.Graphical

Proteomic alterations in the plasma of Beagle dogs induced by Toxocara canis infection

Toxocara canis causes ocular larva migrans and visceral larva migrans in humans. Knowledge about the molecular mechanism of T. canis-hosts interaction is limited. The proteomic alterations in the plasma of Beagle dogs induced by T. canis infection were studied by the quantitative mass spectrometry-based data-independent acquisition (DIA). 418, 414 and 411 plasma proteins were identified at 24 h post-infection (hpi), 96 hpi and 36 days post-infection (dpi), including 6, 5 and 23 proteins with differential abundance, respectively. At 24 hpi, the altered proteins, retinoic acid receptor responder protein 2 (RARRES2), WD repeat-containing protein 1 (WDR1), moesin and filamin-A, may participate in pro-inflammatory reaction or promote larvae migration. At 96 hpi, the altered protein C and fibroleukin may maintain the stability of the coagulation system to protect the lung. At 36 dpi, the alterations of C-reactive protein (CRP), ficolin (FCN), complement factor H-related protein 5 (CFHR5) and other complements can affect the three traditional complement system, including the classic pathway, lectin pathway and alternative pathway. These proteins may play important roles in the interaction between T. canis and its definitive hosts. Further study on these altered proteins triggered by T. canis infection may discovery novel therapeutic or diagnostic targets for toxocariasis. Significance of the studyToxocara canis is one of the globally distributed soil-transmitted helminths, which causes ocular larva migrans and visceral larva migrans in humans and a wide range of warm-blooded animals. T. canis adapts to different microenvironments by resisting and adjusting various biological processes of the hosts. Knowledge about the molecular mechanism of T. canis-hosts interaction is limited. Plasma proteins are good marker for monitoring the occurrence and development of diseases. The proteomic alterations in the plasma of Beagle dogs induced by T. canis infection were studied by the quantitative mass spectrometry-based data-independent acquisition (DIA) in this study. A total of 418, 414 and 411 plasma proteins were identified at 24 h post-infection (hpi), 96 hpi and 36 days post-infection, respectively. Ten protein with differential abundances were validated by using parallel reaction monitoring (PRM). Collectively, our deep proteomic analysis of plasma revealed that proteins alterations were affected by disease development, and proteomic analysis is an ideal method for quantifying changes in circulating factors on a global scale in response to pathophysiological perturbations such as T. canis infection.

Study of toxoplasmosis and toxocariasis in patients suffering from ophthalmic disorders using serological and molecular methods

IntroductionToxoplasma gondii is an intracellular protozoan parasite that can cause ocular toxoplasmosis with most complications such as retinal detachment. Toxocara parasite, round worm, found in dogs and cats appears as larva migrans in humans can cause serious ocular complications such as debilitating vision loss.In Khuzestan province, southwest of Iran, T. gondii infection has been reported to be significant but toxocariasis was rare. However, the frequency of ocular toxoplasmosis and toxocariasis has not been studied in this area. The aim of this study was to evaluate the ocular toxoplasmosis and ocular toxocariasis using serological and molecular methods.MethodIn this case control study, 310 patients were identified by ophthalmologist as ocular toxoplasmosis and then 5 cc of venous blood samples were taken from each of them. Serum samples and buffy coat were prepared and ELISA was used to detect IgG and IgM anti-Toxoplasma antibodies and the molecular PCR was used to detect Toxoplasma DNA parasite in buffy coats. ELISA test was used to detect of IgG anti-Toxocara antibodies.ResultsTotally, for ocular toxoplasmosis, 130 (41.93%) of 310 patients were positive by ELISA, of them 121 (39%) IgG positive and nine (2.9%) IgM positive were diagnosed. Of 121 cases with IgG+, 119 (98.35%) were diagnosed with high IgG avidity indicating chronic phase of the infection. For ocular toxocariasis evaluation, antibodies against Toxocara were not detected in any of the samples. By PCR molecular method, 11 out of 310 patients (3.54%) had T. gondii DNA in the blood. In control, in total, 21 cases were detected positive by serology method, which showed a significant difference with the results of the case group(P < 0.05).By PCR method, only three cases showed positive which also indicated significant difference with result of case group (3 vs 9) (P < 0.05). In the control group, also no anti-toxocara antibodies were found.ConclusionIt can be concluded that T. gondii in Khuzestan province as the etiologic agent of ocular toxoplasmosis and physicians should consider diagnostic methods for identifying the infection when they visit the patients.

Standardization and application of a modified RFLP-PCR methodology for analysis of polymorphisms linked to treatment resistance in Ancylostoma braziliense

BackgroundSingle nucleotide polymorphisms (SNPs) in codons 167, 198 and 200 of the beta-tubulin isotype 1 gene are associated with benzimidazoles resistance in many helminths. Codon 167 mutation has never been described in hookworms; however, polymorphisms in codons 198 and 200 have been described for Ancylostoma caninum and Necator americanus. These mutations have never been investigated in Ancylostoma braziliense; therefore, it is not known if they are present in this species and whether they are correlated with treatment resistance. The RFLP-PCR technique has been used to analyze these polymorphisms in some nematodes, but depending on the species, these alterations do not create or eliminate any restriction enzyme cleavage site, making it impossible to use this technique. Here, we describe the standardization and application of a modified RFLP-PCR technique for detecting polymorphisms in individual A. braziliense worms recovered from naturally infected dogs in two Brazilian states.ResultsThe molecular techniques used were sensitive, specific, and easy to apply. To our knowledge, we report for the first time the presence of a polymorphism at codon 198 of the beta-tubulin gene of A. braziliense (1/81; 95% CI: 0–3.69%).ConclusionsIt is not known whether the presence of the mutation in codon 198 of the beta-tubulin gene of A. braziliense has importance for this parasite. However, based on studies of other helminths, it is possible that this polymorphism is directly related to the resistance to benzimidazoles. This may be a major concern, since this nematode has considerable relevance as a parasite of canids and felids and as one of the agents of cutaneous larva migrans in humans. Standardized methodologies will be useful for screening for polymorphisms in the beta-tubulin gene of canine hookworms in a broader population. The method could also be adapted for the analysis of other SNPs in other nematode species.

Larva Migrans of Baylisascaris potosis In Experimental Animals.

Occurrence of clinical signs by infection with Baylisascaris potosis, the roundworm of kinkajous ( Potos flavus), in mice, rats, and rabbit were studied, and the migration behavior of larvae in mice were compared with that of Baylisascaris transfuga, the roundworm of bears ( Ursus spp.). Three groups of 8 mice, 3 groups of 6 rats, and 3 groups of 2 rabbits were inoculated with either 10, 100, or 1,000 B. potosis eggs. The other 8 mice were inoculated with 1,000 B. transfuga eggs. Animals were monitored for the occurrence of clinical signs until 60 days postinoculation (DPI). The carcass, viscera, brain, and eyes of each of 6 mice inoculated with 1,000 eggs of B. potosis or B. transfuga at 60 DPI were removed individually, and the number of larvae was counted. One mouse inoculated with 100 B. potosis eggs showed rolling at 27 DPI, and 1 larva was found in the medulla oblongata of this mouse. No clinical signs were observed in the other mice or in the rats and rabbits. A mean of 387.2 larvae was recovered from mice inoculated with 1,000 B. potosis eggs, and a mean of 422.0 larvae from mice inoculated with 1,000 B. transfuga eggs. The highest number of larvae was recovered from the carcasses for both B. potosis and B. transfuga. In the viscera, higher numbers of B. transfuga larvae (mean 131.8) were seen than B. potosis larvae (mean 33.1). In the brain, only 1 larva was detected in 1/6 mice inoculated with 1,000 B. potosis eggs, whereas a mean of 21 larvae was detected in mice inoculated with 1,000 B. transfuga eggs. A few larvae (range 0-1) were detected in the eyes of both mice inoculated with B. potosis or B. transfuga eggs. The result indicated that B. potosis larvae do not show a higher tendency to migrate into the brain of mice than B. transfuga larvae. However, 1 mouse inoculated with 100 eggs had 1 larva in the central nervous system and showed a serious neurological sign. This result may underline a potential risk of B. potosis to cause neural larva migrans in humans.

Epidemiology of canine gastrointestinal helminths in sub-Saharan Africa

BackgroundDogs have a close association with humans providing companionship, security and a source of dietary protein. However, dogs are also potential carriers of zoonotic pathogens. Dogs, therefore, pose a public health risk and a good understanding of canine diseases is important for planning and implementing control measures. The aim of this study was to characterise canine helminthiasis in sub-Saharan Africa using a systematic approach.MethodsPubmed and Google Scholar were searched for relevant primary studies published from 2000. Forty-one eligible studies were included in the meta-analysis. Pooled prevalences were estimated using the quality effects model.Results and conclusionsTwenty-six genera of enteric helminths were reported and the pooled estimate of canine helminthiasis was 71% (95% CI: 63–79%). Species of Ancylostoma and Toxocara, causative agents of larva migrans in humans, were the most frequently reported helminths with pooled estimated prevalences of 41% (95% CI: 32–50%) and 22% (95% CI: 16–29%), respectively. Dipylidium caninum and Taenia spp. were the most frequently reported cestodes with pooled estimated prevalences of 20% (95% CI: 12–29%) and 9% (95% CI: 5–15%), respectively. Trematodes were rarely reported. There was a high level of heterogeneity in most pooled estimates (I2 ˃ 80%). The results of this study show that canine helminthiasis is highly prevalent in sub-Saharan Africa and there is need for regular deworming programmes to improve the health status of the dogs and minimise the potential health risk to humans.

Baylisascaris procyonis larva migrans in two white-headed lemurs (Eulemur albifrons) in Spain and response to treatment derived from a human pediatric protocol

Baylisascaris procyonis is a well-known ascaridoid nematode that causes larva migrans in humans and many other animal species. The North American raccoon (Procyon lotor) is the definitive host, which has been successfully introduced in the past decades to other geographical regions around the world. Two white-headed lemurs (Eulemuralbifrons) from a Zoological Park in Lugo, Spain, developed severe neurological signs within a brief period after being transferred from exhibit and placed in close contact with three captive raccoons from the same zoo. One lemur was euthanized due to the severity of disease progression and histopathology revealed granulomatous inflammation and ascaridoid larvae in kidneys, lung, spleen and brain. Larvae were identified as B. procyonis larvae by real time PCR. In light of the results, the cage mate with similar neurological signs was put on an albendazole treatment regimen adapted from a human pediatric protocol. The aggressive anthelmintic treatment likely contributed to the arrest of clinical signs and recovery of some motor skills. Importantly, Baylisascaris procyonis infection might occur in wild raccoon populations in Spain.

Molecular cloning and characterization of arginine kinase gene of Toxocara canis.

Toxocara canis is an important gastrointestinal nematode of dogs and also a causative agent of visceral larva migrans in humans. Arginine kinase (AK) gene is one of the important biomolecule of phosphagen kinase of T. canis which is emerging as an exciting novel diagnostic target in toxocarosis. The present study was carried out to clone and characterize AK gene of T. canis for future utilization as a diagnostic molecule. Total RNA was extracted from intact adult worms and reverse transcription was done with oligo dT primers to obtain complementary DNA (cDNA). Polymerase chain reaction (PCR) was carried out using cDNA as template with specific primers which amplified a product of 1,202bp. The amplicon was cloned into pDrive cloning vector and clone was confirmed by colony PCR and restriction endonuclease analysis. Sequence analysis of the gene showed 99.8 and 77.9% homology with the published AK gene of T. canis (EF015466.1) and Ascaris suum respectively. Structural analysis shown that the mature AK protein consist of 400 amino acids with a molecular wt of 45360.73Da. Further expression studies are required for producing the recombinant protein for its evaluation in the diagnosis of T. canis infection in humans as well as in adult dogs.

Hepatic Visceral Larva Migrans Presenting as a Pseudotumor

h c d l f n i A woman was referred for the assessment of a focal hepatic lesion of fortuitous discovery. The patient’s edical history was remarkable for adenocarcinoma of the reast that had been in remission for 10 years. Routine laboraory results including liver test function and tumor markers ere within normal limits. Imaging study revealed a unique odular lesion of 26 mm in hepatic segment IV, hyperechoic in bdominal ultrasonography, and low density in computed toography (Figure A, arrow). Magnetic resonance imaging showed a nodule that exhibited low intensity in T2 (Figure B, arrow) and high intensity in T1 and presented slightly heterogeneous contrast enhancement after gadolinium injection. Imaging characteristics ruled out focal steatosis, angioma, or focal nodular hyperplasia. In the context of malignancy history, ultrasound-guided liver biopsy of the lesion was conducted. Histologic analysis showed an encapsulated abscess (Figure C). At higher magnification (Figure D), it was made of a mixture of necrotic hepatocytes and large amounts of altered eosinophils, and many Charcot–Leyden crystals, appearing as refringent yellowish spindle-cell structures, were irregularly scattered among these cells. No parasitic structures were visible. Tumoral process was absent. Serologic antibody testing for various helminthic infections was negative except for Toxocara canis, with a titer of 34 U in enzyme-linked immunosorbent assay (normal range, 9 U), and confirmatory Western blot test showed 5 positive bands (normal, 2). This resulted in the conclusive diagnosis of visceral toxocariasis. The patient was managed with albendazole 400 mg 3 times a day associated with ivermectin 12 mg per week for a total of 3 weeks. Magnetic resonance imaging control 6 months after treatment was normal, consistent with favorable outcome. Toxocara canis is the main cause of visceral larva migrans in humans. It may affect multiple visceral organs, and the liver is the most involved site, usually mimicking tumoral processes.1 Lesions are usually described as oval, ill-defined nodules, either unique or more frequently multiple.2,3 Noninvasive approach as been advocated for contributing to diagnostic issue by ombining imaging and serologic testing. Visceral larva migrans iagnosis is to be ascertained when managing investigations for iver nodules caused by eosinophilic infiltrate to disclose them rom metastatic deposits. Treatment of symptomatic forms is ot well codified, and albendazole alone or in combination with vermectin has been reported to be effective.

Geographic Expansion ofBaylisascaris procyonisRoundworms, Florida, USA

Geographic Expansion of<i>Baylisascaris procyonis</i>Roundworms, Florida, USA

Human medical view on zoonotic parasites

Human medical view on zoonotic parasites

Destruição de ovos de Toxocara canis pelo fungo nematófago Pochonia chlamydosporia

Toxocara canis is an ascarid parasite of the small intestine of dogs that causes visceral larva migrans in humans. With the aim of demonstrating the effectiveness of the fungus Pochonia chlamydosporia on Toxocara canis eggs under laboratory conditions, a trial was set up in Petri dishes with 2% agar-water. There was ovicidal activity of 43.8% (p < 0.01) in the treated group in relation to the control group over the periods studied. The results from the present study suggest that Pochonia chlamydosporia can potentially be used as an alternative biological control for embryonated Toxocara canis eggs.

Evaluation of a molecular beacon real-time PCR assay for detection of Baylisascaris procyonis in different soil types and water samples

Baylisascaris procyonis is a helminth parasite commonly found in North American raccoons (Procyon lotor) that is a cause of clinical neural, ocular, and visceral larva migrans in humans when infective eggs are ingested. Rapid detection of B. procyonis eggs in contaminated soil and water would assist public health analysts in evaluating risks associated with public exposure to areas of known raccoon activity. In this study, a molecular beacon probe-based real-time polymerase chain reaction (PCR) assay was developed to enable rapid and specific detection of eggs of Baylisascaris spp. The molecular beacon assay targeted the cytochrome oxidase subunit 2 (cox-2) gene of B. procyonis. To determine method sensitivity, experiments testing various egg levels (250, 25, and five eggs) were performed by seeding into 0.5-g soil samples or 0.5-mL water samples. Different soil sample types were extracted using a commercial nucleic acid extraction kit. Specificity testing using previously characterized helminth tissue specimens indicated that the assay was specific to Baylisascaris spp. Little real-time PCR inhibition was observed for most of the soil and water samples. A seed level of 250 eggs was detected for all soil types, and two seed levels (25 and five eggs) were detected for surface water samples. These results demonstrate that the reported real-time PCR assay was effective for the sensitive detection of B. procyonis in a wide range of soil types, and should be a useful tool for investigations of soil or water potentially contaminated with eggs of this parasite.

Ocular lesions in gerbils (Meriones unguiculatus) infected with low larval burden of Toxocara canis: observations using indirect binocular ophthalmoscopy

To study the frequency of ocular lesions in 30 gerbils infected with 100 embryonated eggs of Toxocara canis, indirect binocular ophthalmoscopy was performed 3, 10, 17, 24, 31 and 38 days after infection. All the animals presented larvae in the tissues and 80% presented ocular lesions. Hemorrhagic foci in the choroid and retina were present in 92% of the animals with ocular lesions. Retinal exudative lesions, vitreous lesions, vasculitis and retinal detachment were less frequent. Mobile larvae or larval tracks were observed in four (13.3%) animals. Histological examination confirmed the ophthalmoscopic observations, showing that the lesions were focal and sparse. In one animal, there was a larva in the retina, without inflammatory reaction around it. The results demonstrated that gerbils presented frequent ocular lesions after infection with Toxocara canis, even when infected with a small number of embryonated eggs. The lesions observed were focal, consisting mainly of hemorrhages with signs of reabsorption or inflammation in different segments of eye, and differing from the granulomatous lesions described in ocular larva migrans in humans.

Toxocarose hépatique pseudotumorale

Toxocariasis is a common helminth infection that causes visceral larva migrans in humans. It has a wide and varied clinical spectrum. A 60-year-old woman consulted after 6 months of recurrent biliary pain with fever. Laboratory tests showed moderate disturbance of liver enzymes and hypereosinophilia (10 400/mm3). Imaging studies revealed a pseudotumor in hepatic segment IV, hyperechoic in abdominal ultrasound and low density in computed tomography. The diagnostic conclusion after ultrasound-guided liver biopsy was unspecific granulomatous hepatitis and eosinophilic infiltrate. The course of the antibody titer to Toxocara canis finally resulted in a diagnosis of Toxocara infection. Outcome was good following treatment with diethylcarbamazine. Some clinical features of liver toxocariasis can mimic tumors and may be interpreted histologically as granulomatous hepatitis, eosinophilic infiltrate of the hepatic portal vein, and/or necrotizing eosinophilic abscesses. Treatment is not yet well codified, but the symptomatic forms call for albendazole or diethylcarbamazine.

Raccoon Roundworms Pose Threat of Neural Larva Migrans

The raccoon roundworm, Baylisascaris procyonis, can cause larva migrans in humans and other animals. Migration of larvae into the central nervous

Pulmonary and Hepatic Involvement of Toxocariasis in an Adult: Case Report

Toxocariasis is known as visceral larva migrans in humans and it is caused by T. canis and T. catis, especially in children, but it is less commonly reported in adults. Although several cases of toxocariasis in adults have been reported, there have been no descriptions of toxocariasis involving the liver or, the lungs and the pleura. We report here on a case of T. canis infection in an immunocompetent adult with peripheral eosinophilia, elevated serum levels of Ig E and CT findings displaying multiple focal air space consolidations in the lungs, bilateral pleural effusion and low attenuated hepatic nodules.

Baylisascaris procyonis in the metropolitan Atlanta area.

Baylisascaris procyonis, the raccoon roundworm responsible for fatal larva migrans in humans, has long been thought to be absent from many regions in the southeastern United States. During spring 2002, 11 (22%) of 50 raccoons trapped in DeKalb County, Georgia, had B. procyonis infection. The increasing number of cases highlight this emerging zoonotic infection.

Assay of nematocidal activity of isoquinoline alkaloids using third-stage larvae of Strongyloides ratti and S. venezuelensis

We examined the effects of isoquinoline alkaloids in vitro in an effort to identify a treatment for Strongyloides stercoralis larva migrans in humans. Infective third-stage larvae of S. ratti and S. venezuelensis were used as model nematodes for S. stercoralis. Nematocidal activity was evaluated by the 50% paralysis concentration (PC 50). Most of the tested isoquinoline alkaloids had activity for S. ratti and S. venezuelensis. We then evaluated in vitro cytotoxicity, which was the 50% inhibition concentration (IC 50) of the compounds using HL60 tissue-culture cells. Three of the compounds (protopine, d-corydaline, and l-stylopine) which exhibited strong nematocidal activity, showed little cytotoxicity. In addition, we examined the relationship between nematocidal activity and cytotoxicity using the PC 50/IC 50 ratio. A ratio equivalent to or lower than that calculated for the currently prescribed strongyloidosis treatments, ivermectin, albendazole and thiabendazole, was observed for allocryptopine, protopine, dehydrocorydaline, d-corydaline, l-stylopine, and papaverine. In contrast, the PC 50/IC 50 ratios for protopine, d-corydaline, and l-stylopine were substantially more favorable. Therefore, protopine, d-corydaline, and l-stylopine were identified as potential effective treatments for strongyloidosis.