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Although human toxocariasis can lead to serious complications including neurological, ocular and visceral complications, there is a lack of comprehensive epidemiological information about the seroprevalence of Toxocara species in humans. In the present study, we analysed and reviewed the overall seroprevalence of human toxocariasis in Iran. The data collection was systematically undertaken on published articles using the PubMed, Google Scholar, ScienceDirect and Scopus databases. A total of 27 studies from the past two decades reporting seroprevalence of human toxocariasis met our eligibility criteria. The pooled proportion of Toxocara infection was estimated as 6.58% (95% confidence interval = 3.98-9.77). A wide variation between different studies was observed (Q statistic = 799.37, df = 26, P  < 0.0001, and I 2  = 96.7%). The seroprevalence rate of toxocariasis in the Iranian population is relatively high; contamination of the environment by eggs from the host as well as from household dogs and cats should be blamed.

The zoonotic roundworms Toxocara canis and T. cati are not only present worldwide in their definitive hosts; they also frequently occur in other animal species, including humans. In those so-called paratenic hosts, the larvae do not develop into the adult stage, but rather migrate throughout the somatic tissue and persist as infectious L3 stage for extensive periods. Those arrested larvae may lead to severe inflammatory reactions and consequently to a wide range of pathological and clinical manifestations. However, the infected paratenic hosts also constitute a potential source of infection for the definitive hosts or humans who may also function as paratenic hosts. In the present review, current knowledge of larval migration in a variety of possible paratenic hosts is summarized including variations of migration routes and susceptibilities. Furthermore, information about the clinical and pathological changes for the presented species and possible consequences of the somatic migration of larvae, i.e. the resulting tissue damage as well as adverse host reactions to arrested larvae are reviewed. There are still many questions unanswered regarding larval behaviour in hosts other than their definitive host. Therefore, it is of great importance to continue further elaboration on the biology of Toxocara spp. to prevent further spreading of larvae in both the paratenic and the definitive host., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Objectives: To present a detailed investigation of risk factors, symptoms, and laboratory and imaging tests that may be useful to establish the clinical laboratory diagnosis of visceral larva migrans (VLM) in children, demonstrating the importance of diagnosis and treatment to prevent complications in the eyes, liver, and other organs., Sources: Literature review using the MEDLINE and LILACS (1952-2009) databases, selecting the most recent and representative articles on the topic., Summary of the Findings: VLM is an infectious disease with non-specific clinical presentation, whose transmission is related to contact with dogs, especially puppies, and which may progress to late systemic complications in vital organs such as the eyes and the central nervous system. IgG (ELISA) anti-T. canis can be used to establish the laboratory diagnosis. Higher cutoff points suggest recent illness and lower cutoff points demonstrate mild infection or infection in remission. Therapeutic response may be assessed by means of eosinophil blood cell count. The present article provides the pediatrician with updated information regarding VLM, a disease of high prevalence worldwide and in Brazil., Conclusions: The diagnosis of VLM depends mainly on the presence of dogs in the child's household, associated with ELISA (IgG anti-T. canis), using excretory-secretory antigens of Toxocara canis. Prospective studies are warranted to assess the best drug therapy. Prevention is the most important strategy because of the high prevalence of T. canis in urban areas.

The clinical presentation of toxocariasis, a zoonotic parasitosis transmitted from dogs and cats to humans, can be very diverse, which is one of the reasons why Toxocara-related disease may go unnoticed. This paper gives a brief summary of the various clinical presentations (covert/common toxocariasis, visceral larva migrans, ocular toxocariasis and neurotoxocariasis), diagnostic and differential-diagnostic considerations as well as treatment and prevention. In brief, the diagnosis of human toxocariasis relies mainly on patient data, anamnestic information, symptoms, eosinophil count and total-IgE levels.

Purpose: The purpose of this study is to investigate the MRI findings of visceral larva migrans (VLS) of Toxocara canis in spinal cord., Materials and Methods: We retrospectively reviewed spinal MRI findings in eight patients with serologically proven Toxocara canis between 2005 and 2008. We evaluated the location, length, extent and migration of the lesion, MR signal intensity (SI), enhancement pattern, and swelling of the spinal cord. We evaluated clinical features including presenting symptoms and signs and treatment response., Results: Total 8 patients (M=8; age range 36-79 years) were included. The lesions were located in the cervical or thoracic spinal cord in all patients. All lesions showed high SI and minimal or mild swelling of involved spinal cord on T2WI and focal nodular enhancement on posterior or posterolateral segment of spinal cord. The length of involved lesion was relatively short in most patients. There was a migration of lesion in one patient. In spite of albendazole or steroid treatment, neurological symptoms or signs were not significantly improved in all patients., Conclusion: Although all lesions show non-specific imaging findings like non-tumorous myelopathy mimicking transverse myelitis, single lesion, focal nodular enhancement on posterior or posterolateral segment of spinal cord, relatively short segmental involvement and migration of lesion may be characteristic findings of spinal VLM of Toxocara canis. In addition, the reluctant response to the treatment may be characteristic of spinal VLM of Toxocara canis., (Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.)

This research was undertaken to determine the seroprevalence of Toxocara canis (T. canis) in children aged 3-13 years in Kütahya, to determine the presence of infected larvae in playground sandboxes, and to obtain a view of the general situation regarding visceral larva migrans (VLM) in the city. The blood sera of 119 children (54 girls, 65 boys) were tested for T. canis IgG, and 9 (7.6%) were found positive. In sand samples collected from playgrounds in nine different residential areas across the city, only two of them, in Inköy and Zafertepe neighborhoods, had T. canis larvae; in total, 3 of the 30 sand samples (10%) contained larvae. It is concluded that the main factor regarding VLM infection in children is outdoor playgrounds or playing areas.

A 14-year-old male, who completed chemotherapy following limb salvage surgery for osteosarcoma approximately 2 years ago, was seen for routine follow-up. A CT scan revealed new scattered multifocal nodular lesions. An ultrasonography-guided percutaneous needle biopsy was done to confirm pulmonary metastasis of the underlying osteosarcoma. The lung biopsy showed findings of eosinophilic pneumonia with no evidence of malignancy. Peripheral eosinophilia was also noted. When a more thorough history revealed frequent intake of raw cow liver, we diagnosed pulmonary toxocariasis by ELISA for specific serum IgG antibody., ((c) 2009 Wiley-Liss, Inc.)

Toxocariasis is one of the causes of eosinophilia in peripheral blood and provokes eosinophilic infiltration in internal organs. In Israel, the number of cases of toxocariasis is very low, 3 cases annually, according to the records at the Ministry of Health. Many cases of eosinophilia might be misdiagnosed as hypereosinophilia syndrome (HES), if serological testing for Toxocara is not conducted, leading to inappropriate treatment. The test is for specific serum IgG antibody of Toxocara canis antigen measured by enzyme-linked immunosorbent assay (ELISA). The authors present a 4 year old girl with hypereosinophilia of 40,000 cell/microl, without involvement of target organs. The authors found that toxocara was the cause of hypereosinophilia. After appropriate treatment the number of eosinophils decreases, presenting a measurement of the parasite activity.

This survey was conducted to determine prevalence of Toxocara spp. eggs and seasonal variation of this prevalence in public parks in Ankara, Turkey. A total of 259 sand samples were collected from May 2005 to April 2006 in 40 public parks for determining prevalence. To attain seasonal variation, a total of 696 sand samples were collected from five public parks regularly throughout year. Prevalence of Toxocara spp. and combination of Toxascaris leonina and Taenia spp. was 15.05% and 0.38%. Overall, 45% of public parks were contaminated. There was a seasonal variation in prevalence. Prevalence of Toxocara spp., Toxascaris leonina, and Taenia spp. eggs during summer (4.21%) was lower than during spring (12.64%), autumn (13.21%), and winter (9.77%; p < 0.05). Average number of Toxocara spp. eggs was 2.57 per 50 g of sand, with average dimension of 70.1 mum. In conclusion, prevalence data are consistent with international data reported in other metropolitans. Our results indicate that the public parks in surveyed areas may be a source of toxocariasis. Effective preventive measures should be established.

Unlabelled: Toxocara canis is a common intestinal helminth found in dogs. In humans, it is a cause of Visceral Larva Migrans (VLM), a zoonosis rarely studied in Mexico. The aim of this study is to examine, by means of the indirect haemaglutination test (IHAT), the prevalence of antibodies of T. canis in the serum of stray dogs in Mexico City., Methods and Materials: 141 stray dog serum samples from three different districts of the city were analyzed: Iztacalco (49), Iztapalapa (49) and Coyoacan (43). In each location three study groups were formed. Group I with 35 dogs (less than a year old), Group II with 91 dogs (ages 1

Introduction: Visceral larva migrans, a syndrome observed in humans, is caused by larva of parasitic helminths, such as Toxocara spp., which usually infect dogs and cats. Among the risk factors involved in the incidence of this syndrome, the size of these animal populations is particularly important. Ciudad Bolívar (Bolivar State, Venezuela) is a city with a large dog population. This fact has led to an effort to determine of prevalence of eggs from Toxocara spp. and other helminths in public squares and parks in this city., Methods: Twenty-five squares and parks were selected from five areas of the city. Soil samples (20 sites) and dog stools (12 sites) were collected from four separate parts of each square or park. Samples were processed by spontaneous sedimentation and saturated sodium solution methods., Results: Among the 70 squares and parks in Ciudad Bolívar, 25 were studied (35,7%). Toxocara eggs were identified in 55% of soil samples and 16.7% of dog stools. Ancylostoma spp. was detected in 61.1% of stools evaluated. There were no differences in helminth detection related to the area of the city where samples were obtained., Conclusion: Public parks and squares in Ciudad Bolívar showed a high percentage of contamination by dog helminths. These results suggest a potential risk of zoonotic transmission of dog parasites in these public places.

The syndrome of visceral larva migrans was described for the first time in 1952 by Beaver. He demonstrated that the presence of nematodes larvae, particularly in the liver, were those of Toxocara canis and T. cati. Baylisascaris procyonis, the common racoon ascarid in the U.S.A. can also cause serious diseases in human. Digestive and respiratory clinical symptoms are usually moderate, however severe disease resulting from invasion of the myocardium or the brain has been reported. A blood hypereosinophilia is usually present the first few years after infection. Diagnosis uses serological methods, among them the ELISA test. Ocular larva is also possible with in that case, immunological modifications of the aqueous. Cutaneous larva migrans characterized by a linear, progressing, serpigenous eruption and intense itching is easy to diagnose. Larva migrans is due to dogs, cats and horses helminths. Dogs and cats (referred here as pets) now receive antihelmintitic treatments and parasites are now in decrease.

We report a familial case of visceral larva migrans (VLM) caused by Toxocara canis larvae. Patient 1 was a 45-year-old man who presented to our university hospital complaining of mild fever, general fatigue, and headache. Patient 2 was a 71-year-old man and was the father of Patient 1; he presented complaining of cough and hyper-viscous white sputum. Laboratory data from both patients showed extensive eosinophilia, their chest X-ray findings revealed multiple pulmonary infiltrates, and their bronchoalveolar lavage fluid (BALF) showed an elevated eosinophil count. The diagnosis of VLM was made based on a positive result in a serological test using T. canis larval excretory-secretory both in the serum and BALF. T. canis larvae were identified in meat that was prepared from chicken taken from the same source as that ingested. This is the first report to identify antibodies in BALF in patients with VLM.

Few studies have been conducted in the United States to quantify the potential risk associated with encountering zoonotic ascarid ova in the environment. In an effort to raise awareness and to better understand the risk of acquiring visceral larva migrans in south central Connecticut, this environmental survey was conducted to determine the prevalence of ascarid ova (Toxocara canis, Toxocara cati, Baylisascaris columnaris, and Baylisascaris procyonis) in public areas of Wallingford, Connecticut, to compare prevalence levels among these public areas, and to determine what host species are primarily responsible for environmental contamination. A preliminary study was conducted to determine if ascarid ova of different species could be identified by size and appearance utilizing light microscopy alone; results did not support the differentiation of species via these methods. To determine the prevalence of environmental contamination with ascarid ova, samples of approximately 250 g of soil were collected from park green areas, playgrounds, public housing areas, parkways, and a school. Ova were detected in 46 (14.4%) of 319 samples collected. Ova were collected from three of the 60 (5.0%) park green area samples, 11 of the 40 (27.5%) playground samples, six of the 98 (6.1%) public housing samples, and 26 of the 96 (27.1%) parkway samples. Public areas of Wallingford, Connecticut are frequently contaminated by potentially infectious ascarid ova. Of particular concern is the high degree of contamination of playgrounds and the potential risk these areas pose to children's health.

In a recent publication it was suggested that human toxocarosis, including ocular larva migrans, may result from petting dogs infected with Toxocara canis, the dog roundworm. Recalculating the eggs per gram in the dog's coat revealed that in 7 of the 15 positive dogs only one Toxocara egg per dog was found. Only 4% of all eggs were embryonated and hence infectious. It is, however, very plausible that this is contamination originating from the environment. The authors found also many other parasite eggs and free-living larvae in their samples, which points to the dog being merely a passive transport host. The risk to man of acquiring the infection by stroking a dog is therefore considered to be extremely limited.

A 46-year-old Swiss woman presents with intermittent abdominal pain and persistent eosinophilia that is suggestive of helminthic etiology. Though her stay in Africa goes back > 35 years, an imported disease is a possibility. However, contact with a puppy suggests a locally acquired organism. Antibodies to filariae and Toxocara are demonstrated in the serum. Following treatment with albendazole 400 mg daily for 14 days the patient makes a full recovery, and the final diagnosis is active Toxocara canis infection.

One hundred and seventy soil samples from forty-six public parks in Ankara area were examined to determine the level of contamination with Toxocara spp. eggs. 30.6% of the 170 soil samples were contaminated with Toxocara spp. eggs. The number of eggs in the positive soil samples varied from 1 to 10. A high proportion of the eggs was fully embryonated. The findings demonstrate the common occurrence of these eggs in locations likely to be important in the transmission of visceral larva migrans. Of 19 fecal collected, 5 (26.3%) contained Toxocara spp. eggs. Eggs of Ancylostomidae, Toxascaris leonina, Trichuris spp., Taenia spp. and Enterobius vermicularis were also recovered from 17.6, 4.1, 2.4, 1.8 and 1.2% of soil samples, respectively.

A 13-month-old boy developed eosinophilic meningoencephalitis, retinitis, and a protracted encephalopathy with severe residual deficits. The initial MR examination revealed diffuse periventricular white matter disease, and follow-up images showed atrophy. Brain biopsy, serology, and epidemiologic studies lead to the diagnosis of Baylisascaris procyonis infection, a parasitic disease contracted through exposure to soil contaminated by the eggs of a common raccoon intestinal roundworm. The pathologic, epidemiologic, and imaging features of this disease are herein reviewed.

Beach sand was examined and analysed in 1997 at several locations in Warnemünde, a North-East German seaside resort, especially for the incidence of the nematode genuo Toxocara. Two of 126 samples contained Toxocara. The author points out measures to decrease the risk of infection.

Toxocarosis is the clinical disease in man caused by infection of zoonotic roundworms of dogs and cats, Toxocara canis and T. cati. In this review the mode of transmission to the human by oral ingestion of Toxocara eggs from the environment is discussed. T. cati seems to play a more important role than generally suggested. Direct contact with animals is not considered a potential risk because embryonation of excreted Toxocara ova requires a minimum of 2 weeks. For the same reason there is no relationship expected between infection and exposure to dogs and cats in the household. Children more frequently have clinical symptoms because of the closer contact with contaminated soil in yards and sandpits, the lack of hygiene, and because of eating dirt. Toxocara larval migration in the body can cause various clinical syndromes. Visceral larva migrans, ocular larva migrans, and covert toxocarosis are described. Serodiagnostic techniques are reliable tools to detect antibodies or antigens. Systemic treatment with anthelmintics is described but can result in hypersensitivity reactions caused by dying larvae. For ocular lesions, laser photocoagulation and corticosteroid therapy are described. Preventive measures consist of preventing contamination of the environment with Toxocara eggs and for education of pet owners and non-pet owners to increase awareness about potential zoonotic hazards. Veterinary practitioners, general practitioners, and public health agencies should therefore provide sufficient information and advice.

The surface of T. canis is now recognized as a dynamic structure which turns over quite rapidly and serves as a renewable source of large quantities of antigen(s). The major host responses to these antigens include a marked eosinophilia and hyperglobulinemia. Both of these responses are apparently ineffective at ridding the body of infective larvae. Both eosinphils and IgE antibodies are manifestations of the Th2 subset of T helper cells and the cytokines that they secrete. Further, there is reason to believe that the antigens released from T. canis larvae favor the induction of this cellular population. Finally, there is mounting evidence that the chronic production of parasite antigen and its continued stimulation of the host immune system with a concomitant production of eosinophils can lead to a permanent alteration of the normal organization of the cardiopulmonary system. In the absence of any well-documented drugs capable of killing infective larvae, it would seem that immunological intervention may offer the only way to minimize or neutralize this 'gift from man's best friend'. This chapter was not intended to be an exhaustive review of the literature pertaining to toxocariasis. Several other recent publications will hopefully fulfill the need for more detailed information on the biology of this organism and the clinical spectrum of the disease it produces [16, 138-140]. Finally, a MEDLARS search of the current medical literature should bring anyone up to speed in a very short time.

Some aspects of dog toxocarosis and syndrome of visceral larva migrans in human toxocarosis, particularly in children were presented. In detail the morphological characters and biology of Toxocara canis, its pathogenicity, ways of invasions as well as conditions favouring the spreading of parasites were discussed. Attention was paid to the efficacy of diagnosis of invasions, treatment and prophylaxis. The current toxocarosis threat was analysed and epidemiological prognosis was moved forward.

Human toxocariasis is a zoonotic infection which characteristically presents either as visceral or ocular disease. Some patients are asymptomatic. The real incidence of symptomatic infection and its natural history, and the likelihood of congenital infection, are unknown. Collaboration between clinicians, epidemiologists and microbiologists should help to resolve these questions.

The authors selected among 5 diagnosed cases of larva migrans. In this study, the authors reported a review of this disease.

An enzyme-linked immunosorbent assay (ELISA), employing antigens from Toxocara canis larvae and the absortion of suspected sera with Ascaris lumbricoides extracts was used in a seroepidemiological study performed in five municipalities of São Paulo State, Brazil (São Paulo, Campinas, Santos, Marília and Presidente Prudente) in order to determine the frequency of antibodies to Toxocara. In 2,025 blood samples collected, 806 proceeded from male subjects and 1,219 from females; 483 samples were collected from subjects under 15 years of age and the remaining 1,542 from subjects aged 15 years or over. Among the 2,025 sera investigated, 3.60% had antibodies to Toxocara at significant levels. A moderate predominance of infection with Toxocara among male subjects (3.72%) was observed, although the difference was not statistically significant when this rate was compared with that for female (3.28%). Related to age, a higher frequency of positive results was detected among subjects under 15 years (6.41%) against the older group (2.53%). A trend of more elevated rates of infection was observed in municipalities with high demographic densities (São Paulo, Campinas and Santos). Nevertheless, such findings only appeared to be statistically significant in subjects younger than 15 years.

Reports of Visceral larva migrans (VLM) are not frequent in Brazil, but the prevalence of this disease may be more common due to poor environmental conditions to which most of the children are exposed. The most common infectious agent is Toxocara canis, a parasite of the intestinal tract of dogs. Children get infected eating contaminated material with feces of dogs. The ova are swallowed and reach the intestinal lumen of the children. Systemic migration occurs by lymphatic or portal circulation to several organs, most frequently, to the liver and lungs, causing hepatosplenomegaly and/or bronchospasm.

A review is given on the occurrence of Toxocariasis, the prevalence of T. canis among dogs and investigations on the prevalence of infective ova in soil- and sandsamples. The resistance of ascarid eggs and larvae against different environmental influences, including various sewage treatment-effects is discussed. The eggs are destroyed in 7 minutes when kept at 55 degrees C in a high humidity, slower when the humidity is lowered. When the temperature is -32 degrees C T. canis eggs are inactivated after 8 hours. Complete embryonation is reached in 4 days when the temperature is 30 degrees C. Potential ways of transmission to man are outlined (pica, vegetables, bathing etc.) and recommendations in order to prevent the disease are given such as deworming of dogs, methods to decimate occurrence of eggs in wastewater and sludge etc.

Visceral larva migrans, VLM, is a disease of young children. Due to lack of awareness of the disease as well as its non-specific symptomology, a survey of the potential risk of acquiring the disease was conducted in the Baton Rouge, Louisiana area. The greatest number of dogs showing positive results to tests for the presence of the eggs of Toxocara canis were those less than one year of age. Very few of the soil samples collected from twenty different parks/playgrounds were found to contain eggs of T. canis. A higher percentage of soil samples from individual yards proved to be contaminated with the eggs of the parasite. Even though the incidence of VLM in Baton Rouge is reported to be quite low, the potential for the infection certainly is present. Veterinarians must be prepared to take a leading role in the education of their clients as to the potential of the disease for the children associated with new puppies, and the measures parents can take to reduce the exposure potential.

Blood samples were obtained during a lead screening program from 100 children aged 1-6 years in Allegheny County, Pennsylvania, to determine whether there was any association between specific forms of pica and infection with Toxocara canis, the principal cause of visceral larva migrans in the United States, or elevated blood lead levels. Significant associations were found between: 1) feces, soil, or grass pica and Toxocara infection; 2) paint or plaster pica and elevated blood lead; and 3) dog ownership and Toxocara infection. These findings suggest that an accurate pica history may be useful in identifying potential health problems in children.

Between 1982 and 1985 18 sand-pits were examined for Toxocara canis eggs. Eggs were found in 4 sand-pits. This implies a risk of larva migrans visceralis infection for children playing in these sand-pits. Some measures for diminishing the contamination are recommended.

A seroepidemiologic investigation was conducted in order to determine the cause of an apparent increase in rates of eosinophilia among 1400 institutionalized children during 1976-1977. The annual serologic survey during this period revealed 283 (20%) individuals with eosinophilia that exceeded 600 cells/cu mm of blood. During a five-month period in 1977, five patients who were hospitalized in adjacent wards developed acute pneumonia with eosinophilia. Because laboratory tests of sputum, bone marrow, and stool failed to identify the etiologic agent, it was thought that these pneumonia cases might be related to the increased rates of eosinophilia. Analyses of random samples of sera from patients with eosinophilia revealed seroprevalence rates of 12% for Ascaris, 20% for Toxocara canis, 24% for Strongyloides stercoralis, and 32% with increased antibody to Entamoeba histolytica. Further investigation showed a statistically significant positive association between occurrence of eosinophilia and pica behavior, and eosinophilia and contact with dogs. Although the serologic survey showed patients to have had previous exposure to a variety of parasites, we hypothesize that a principal cause of eosinophilia among institutionalized children may be Toxocara infestation, due to their frequent pica behavior and, in this case, contact with resident animals. We recommend that children in similar facilities have limited contact with pet dogs, and only after frequent and vigorous examination of the animals for infectious parasites.

Pets are not a major source of human infections but they can transmit certain diseases to man. This transmission usually is complex, requiring close contact with pets or their excretions and frequently involves a breach of sound hygienic practice. In some instances, pathogens of animal origin are acquired inadvertently because infectivity can persist after evidence of gross contamination has gone. Veterinarians participate in controlling zoonotic diseases by encouraging rabies vaccination and hygienic treatment of pet feces and urine, by supporting community efforts toward responsible pet ownership and by advising on precautions for handling sick animals. It is recommended that veterinarians discourage the keeping of wild or exotic animals as pets and excess fondling of pets (particularly by children and pregnant women). Clients and kennel workers should be advised to use caution with animals that have aborted.