Visceral Larva Migrans In Humans Research Articles

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.

Incidence of Ascaris suum-specific antibodies in Austrian patients with suspected larva migrans visceralis (VLM) syndrome.

The pig roundworm, Ascaris suum, is commonly found in domestic pigs all over the world. The transmission to humans takes place by ingestion of infective A. suum eggs present in soil because pig manure is widely used as fertilizer. The possible role of A. suum in the human visceral larva migrans (VLM) syndrome has been discussed controversially during past decades, even though various case reports, particularly from Japan document pulmonal, hepatic and even cerebral symptoms caused by migrating A. suum larvae after ingestion of infected row meat (liver) or contaminated vegetables. We examined 4481 sera by A. suum immunoblot (As-IB) and 5301 sera by Toxocara-ELISA from patients with symptoms associated with the VLM syndrome during three consecutive years (2012-2014). The incidence of A. suum-specific antibodies was 13.2 %, the incidence of T. canis specific antibodies 12.9 % and from a part of the As-IB positive sera (n = 417) additional Toxocara serology was performed to demonstrate the specificity of our tests. Only 56 out of the 417 (13.4 %) sera showed antibodies to both helminth species demonstrating that double infections exist. Interestingly the age distribution of the patients showed that 2.8 % of the Ascaris-positive patients were younger than 21 years, while in the Toxocara-positive group 13.4 % were <21 years. These results are in accordance with a Dutch study suspecting different ways of transmission as cause for this interesting age distribution. Due to the fact that large amounts of untreated pig manure are used as fertilizer and that the expulsion of adult A. suum worms causing intestinal ascariosis is extremely rare in Central European countries, the zoonotic potential of A. suum is considerably underestimated. We suggest that the performance of reliable immunoserological tests, in all industrialized countries where pigs are raised and their manure is used as fertilizer, could help to assess the actual potential of A. suum as causative agent of the VLM syndrome in humans.

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.

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.

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.

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.

Visceral larva migrans: migratory pattern of Toxocara canis in pigs

The migratory pattern of Toxocara canis was investigated following infection of pigs with 60 000 infective eggs. Groups of six pigs were slaughtered at 7, 14 and 28 days after infection (p.i.), and the number of larvae in selected organs and muscles was determined by digestion. A group of uninfected pigs was used as negative controls for blood parameters and weight gain. Toxocara canis migrated well in the pig, although the relative numbers of larvae recovered decreased significantly during the experiment. On day 7 p.i., high numbers of larvae were recovered from the lymph nodes around the small intestine and to some extent also from the lymph nodes around the large intestine, and from the lungs and the liver. On day 14, the majority of larvae were recovered from the lungs and the lymph nodes around the small intestine, and by day 28 p.i. most larvae were found in the lungs. Larvae were recovered from the brain on days 14 and 21, with a maximum on day 14 p.i. No larvae were found in the eyes. Severe pathological changes were observed in the liver and lungs, especially on day 14 p.i.; also, development of granulomas was observed in the kidneys. Finally, a strong specific antibody response towards T. canis L2/L3 ES products was observed from day 14 p.i. until termination of the experiment, and the maximum eosinophil response was observed 14 days p.i. The pig is a useful non-primate model for human visceral larva migrans, since T. canis migrate well and induce a strong immunological response in the pig. However, the importance of the pig as a paratenic host is probably minor, because of the relatively early death of most of the larvae.

Chicken liver as an important route of infection with larval ascarid nematodes to cause human visceral larva migrans

Chicken liver as an important route of infection with larval ascarid nematodes to cause human visceral larva migrans

The extraparasitic life cycle of Toxocara vitulorum in the village environment of Sri Lanka.

The extraparasitic life cycle of Toxocara vitulorum of buffalo in the villages of Sri Lanka is related to observations on buffalo behaviour, experimental studies on the development and persistence of the eggs in soil and in wallows and the presence of eggs in village locations. Calf faeces on soil were rapidly incorporated by insect activity and the eggs developed only slightly slower than in the laboratory. Some infective eggs persisted 3-4 cm deep for 17 months, finally dying during a prolonged hot, dry period. Eggs in a wallow developed intermittently over 16 months as it was flushed with rain water, and eventually died when the wallow dried out. When infected faeces were placed in water, decomposition caused some material to rise to the surface and eggs developed. In villages, eggs are ubiquitous where young calves are kept but survive best where there is moisture and shade around animal pens and wallows. Cows and calves acquire infection from infective eggs in wallow water, soil and pasture, while calves may also be infected from contamination on the udder and teats of the cow. The larvae resulting from this infection do not mature until the infection is passed to the calf through the milk of the cow. At least 72% of village calves have patent infections and current treatment procedures do not reduce the prevalence. The possibility that T. vitulorum is a cause of human visceral larva migrans is discussed.

Species‐specific and common epitopes on the secreted and surface antigens of Toxocara cati and Toxocara canis infective larvae

It is widely accepted that the major cause of visceral larva migrans (VLM) in man is Toxocara canis infection. This has been largely based on the detection of antibodies to this species. We have compared the antigens of T. canis and Toxocara cati in order to establish whether assay for the former might be compromised by infection with the latter. Comparisons were made by radioiodination of the surface and excretory/secretory (ES) glycoproteins of the infective larvae of both species, immunoprecipitation with poly- and monoclonal reagents, and SDS-PAGE. The SDS-PAGE profiles of surface antigens of the two species showed few similarities, whereas that of the ES material indicated considerable homology. Serum from infected animals and a human VLM patient exhibited complete cross reactivity, although there was evidence in the mouse of a specific response to one of the components of T. cati ES. Testing of ES against a panel of monoclonal antibodies (MoAbs) confirmed the similarity; all but one of the MoAbs recognized several of the components of both sources of ES. The only exception was MoAb Tcn-2, which did not react with T. cati surface, somatic or ES antigens. This antibody is known to recognize a carbohydrate determinant which is widespread on T. canis glycoproteins. This species-specific determinant, therefore, represents a reversal of the consensus that peptide determinants tend to be the more specific. Finally, the MoAbs were used to examine the exposure of shared epitopes on the surface of intact larvae of T. cati. Again, fine differences in binding by anti-carbohydrate monoclonals were observed when the two species of Toxocara were compared, reflecting a distinction in exposure or orientation of surface molecules on these nematodes. Moreover, these epitopes were absent or variably present on the surface of freshly hatched larvae, and full exposure did not occur until about 24 h post-hatching. This delay in the presentation of epitopes might have implications for the process of infection in sensitized hosts. In conclusion, it is probable that the serological response in man to T. canis is, by current serological methods, indistinguishable in specificity from that induced by T. cati infection, and that the MoAb which we describe could be used to permit discrimination.

Visceral Larva Migrans and Alveolar Hydatid Disease: Dangers Real or Imagined

For both visceral larva migrans and alveolar hydatid diseases, it is the feces of companion animals that are the primary source of human infection. Clearly, whatever is done to reduce this form of environmental contamination and the prevalence of the parasites' infective stages will help to protect the health of the human population in the United States and Canada, particularly the children. Very important are appropriate anthelmintic treatment programs, especially for T. canis, and proper control of close associations between pets and people. Probably the known incidence of visceral larva migrans in humans and the range of its known pathogenicity will increase as better diagnostic methods become available. In addition, other animal helminths, for instance Toxocara cati and Toxascaris leonina, may become more substantially documented as causes of human visceral larva migrans. Until more is known of the geographical distribution and prevalence of Echinococcus multilocularis among animals in North America, it will be difficult to assess accurately the future significance of alveolar hydatid disease in the continent's human population. Another important advance would be the development of anthelmintics that are effective for somatic second stage larvae of T. canis, and others effective for adult or larval Echinococcus species. Meanwhile it is a most important responsibility of the veterinary profession to educate its clients thoroughly concerning these dangerous helminths.

Studies On The Inducing Possibility Of Human Visceral Larva Migrans Associated With Eating Habit Of Raw Liver Of Domestic Animals

To observe the possibility of human visceral larva migrans due to eating of raw liver of domestic animals, especially of cattle, and also to serve as a good reference for adequate sanitary measures, the investigation survey was carried out from May 1975 to May 1976. From the subjects of a l,048 inhabitants (male 558, female 490) in five localities including two Provinces and three different cities, food habit was studied by questionnaire mannual. Larvae isolated from liver tissues of cattle, and pig were identified. Experimental observation on the chicken and mice infected with Toxocara canis was undertaken to draw a assumption of possibility inducing human visceral larva migrans. The results obtained from the present study are summarized. 1. A part of Korean people has the habit to eat the livers of cattle, fowl, pig and dog raw. Eating rate of raw beef liver was 37.8% out of l,048 inhabitants, and its rate was higher markedly in male(57.7%) than in female (15. 1%), and the highest rate among the group of 31-40 years old. Eating rate of raw liver of fowl was 5.9%, pig 5.3%, and dog 2.5%. 2. Larva recovery rate from beef liver was 11.8% out of 195 samples and 72.0% of total detected 1arvae were identified as Toxocara(=Neoascaris) vitulorum. From pig liver, larvae of nematoda were found in 6.4% out of 109 samples but no larva was detected from 120 fowl livers. 3. Larvae detected from one-half of tissues and organs of infected chicken with about 2,000 Toxocara canis eggs were 8-245 in number, and 85-100% of recovered larvae were from their 1iver tissues. 4. Toxocara canis larvae, 45, 31, 42 and 23 in number at 3rd, 14th, 25th and 55th day in one-half of the tissues and organs after infection respectively, were demonstrated from the mice infected with 500 larvae collected from infected chicken liver. Most of the larvae were recovered from the carcass of the mouse. It was approved the larvae isolated from chicken possess infectivity to the mice. 5. Typical eosinophilic granulomatous change was not observed in the liver tissue of the infected chicken at 20th day after infection. As it summarized above, the liver of various domestic animals is the favorite tissue for migration of nematodes larvae. Therefore, the possibility of human visceral larva migrans may be induced due to eating of raw liver of domestic animals.

Visceral larva migrans in the dog.

It has been known that in the course of their migration, Toxocara canis larvae wander widely through various tissues of the dog. It has also been known, from experimental infections, that some of these larvae are arrested in the course of their migration and remain in visceral tissues unable to either develop or proceed further. These facts were established from digestion experiments, and the effects of the arrested larvae on the host were known in but few tissues. We have found that granulomas form around such larvae, and that these occur in a wide variety of tissues: kidney, liver lung, myocardium, skeletal muscle, thyroid, pancreas, pituitary, lymph node, intestine, retina, brain and cauda equina. The larvae in the granulomas were identified as Toxocara species, presumably T. canis. The lesions resemble those of human visceral larva migrans, but do not elicit clinical signs. Because they occur in the same host that harbors the adult worm, the previously accepted definition of visceral larva migrans is too narrow, and it is proposed that this term be applied to any visceral lesions produced by migrating helminthic larvae.