Status of human toxocariasis, a neglected parasitic zoonosis in Iran: a systematic review from past to current.

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 I2 = 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.

Toxocara spp. infections in paratenic hosts.

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.

Toxocariasis: visceral larva migrans in children.

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.

Toxocaríase: larva migrans visceral em crianças e adolescentes / Toxocariasis: visceral larva migrans in children

OBJETIVOS: Apresentar investigação detalhada de fatores de risco, sintomatologia, exames laboratoriais e de imagem que possam contribuir para o diagnóstico clínico-laboratorial da larva migrans visceral (LMV) em crianças e mostrar a importância do diagnóstico e do tratamento para evitar complicações oculares, hepáticas e em outros órgãos. FONTES DOS DADOS: Revisão de literatura utilizando os bancos de dados MEDLINE e LILACS (1952-2009), selecionando os artigos mais atuais e representativos do tema. SÍNTESE DOS DADOS: LMV é uma doença infecciosa de apresentação clínica inespecífica cuja transmissão está relacionada ao contato com cães, principalmente filhotes, podendo evoluir com complicações sistêmicas tardias em órgãos vitais como o olho e sistema nervoso central. Para diagnóstico laboratorial, pode ser utilizado IgG (ELISA) anti-Toxocara canis, cujos pontos de corte mais elevados sugerem doença recente e, os mais baixos, infecção leve ou em resolução. A resposta terapêutica pode ser avaliada por meio da contagem de eosinófilos no sangue. Esse artigo atualiza o pediatra em relação à LMV, doença de alta prevalência no mundo e no Brasil. CONCLUSÕES: O diagnóstico de LMV depende principalmente da epidemiologia da presença de cães no domicílio da criança, associada ao ELISA (IgG para T. canis), utilizando antígenos Toxocara de excreção e secreção. São necessários estudos prospectivos para avaliar a melhor droga na terapêutica. A prevenção é a estratégia mais importante devido à alta prevalência de T. canis na região urbana.

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.

[Toxocariasis]. / Toxocariasis.

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.

Visceral larva migrans among children in Kütahya (Turkey) and an evaluation of playgrounds for T. canis eggs.

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.

MRI findings of spinal visceral larva migrans of Toxocara canis.

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.

Pulmonary toxocariasis masquerading as metastatic tumor nodules in a child with osteosarcoma.

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.

[Toxocariasis as a cause of hypereosinophilia].

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.

Seasonal prevalence of Toxocara ova in soil samples from public parks in Ankara, Turkey.

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.

Prevalence of anti-T. canis antibodies in stray dogs in Mexico City.

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

[Toxocara spp. and other helminths in squares and parks of Ciudad Bolívar, Bolivar State (Venezuela)]. / Toxocara spp. y otros helmintos en plazas y parques de Ciudad Bolívar, estado Bolívar (Venezuela).

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.

[Visceral and cutaneous larva migrans]. / Larva migrans viscérales et cutanées.

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.

Contaminação por fezes caninas das praças públicas de Cuiabá, Mato Grosso / Contamination for faecal samples dogs of the public squares of Cuiabá, Mato Grosso

O presente trabalho teve o objetivo de avaliar a contaminação das praças públicas de Cuiabá, Estado de Mato Grosso, por fezes de cães. Foram pesquisadas 55 praças, de agosto a novembro de 2006. Destas, 14 localizavam-se no centro da cidade e 41 em diversos bairros periféricos do município. As amostras foram coletadas pela manhã, armazenadas em sacos plásticos sob refrigeração e processadas no Laboratório de Doenças Parasitárias do Hospital Veterinário da UFMT, através das técnicas de Willis-Mollay e Hoffmann, Pons e Janer, 1934. Das 55 praças, 40 possuíam amostras de fezes de cães. Ao todo foram coletadas 121 amostras e em 45 foram observados ovos de helmintos. Destas, 38 (84,4%) apresentaram ovos de Ancylostoma sp; 07 (15,5%) de Toxocara sp; 09 (20%) de Trichuris vulpis e 01 (2,2%) de Platynossomum sp e Cystoisospora sp. Vinte e duas das 121 amostras encontradas foram nas praças centrais e 99 nas de bairros periféricos, entretanto não houve diferença estatística significativa (p>0,05) entre as mesmas. Este estudo revelou alta contaminação de praças públicas da cidade de Cuiabá por ovos de helmintos, incluindo os de importância em saúde pública, o que indica risco de transmissão dessas zoonoses a população.

The present work had the objective to evaluate the contamination of the public squares of Cuiabá, State of Mato Grosso, for faecal samples of dogs. Fifty five squares had been searched, of August the November of 2006. Of these, 14 beed situated in the center of city and 41 in diverse outlying areas of the city. The samples were collected per the morning, stored in processed plastic bags under refrigeration and in the Laboratory of Parasitic Illnesses of the Hospital Veterinarian of the UFMT, through the techniques of Willis-Mollay and Hoffmann, Pons and Janer, 1934. Of the 55 squares, 40 had faecal samples of dogs. To 121 samples had been all collected and in 45 eggs of helminths had been observed. Of these, 38 (84,4%) had presented eggs of Ancylostoma sp; 07 (15,5%) of Toxocara sp; 09 (20%) of Trichuris vulpis ones and 01 (2,2%) of Platynossomum sp and Cystoisospora sp. Twenty and two of the 121 joined samples had been in the squares central offices and 99 in the ones of outlying areas, however did not have difference significant statistics (p>0,05) between the same ones. This study it disclosed high contamination of public squares of the city of Cuiabá for eggs of helminths, including of importance in public health, what it indicates risk of transmission of these zoonosis the population.

A familial case of visceral larva migrans after ingestion of raw chicken livers: appearance of specific antibody in bronchoalveolar lavage fluid of the patients.

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.

A survey of environmental contamination with ascarid ova, Wallingford, Connecticut.

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.

[Negligible risk of visceral or ocular larva migrans from petting a dog]. / Verwaarloosbaar risico op viscerale of oculaire larva migrans door het aaien van een hond.

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.

[Eosinophilia, diarrhea]. / Eosinophilie, Durchfall.

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.

Ocorrência de larva migrans na areia de áreas de lazer das escolas municipais de ensino infantil, Araçatuba, SP, Brasil / Presence of larva migrans in sand boxes of public elementary schools, Brazil

A areia das áreas de lazer de escolas podem constituir vias de transmissäo para várias zoonoses parasitárias, representando risco potencial para as crianças que brincam nesses locais. Foi avaliada a ocorrência de agentes de larva migrans em 28 escolas municipais de ensino infantil de Araçatuba, SP. Foram colhidas 535 amostras de areia das áreas de lazer dessas escolas nos meses de janeiro (veräo) e julho (inverno) de 1997 para estabelecimento da freqüência de isolamento de larvas e/ou ovos de Ancylostoma spp. e de ovos de Toxocara spp., pelos métodos de centrífugo-flutuaçäo e de Baermann, respectivamente. A presença de larvas de Ancylostoma spp. foi observada em, pelo menos, uma das amostras, em 35,7 por cento (10/28) das amostras da primeira colheita (veräo) e em 46,4 por cento (13/28) quando da segunda colheita (inverno). Ovos de Toxocara spp. näo foram encontrados e a presença de ovos de Ancylostoma spp. foi observada em 0,56 por cento (3/535) das amostras

Prevalence of Toxocara spp. eggs in the soil of public parks in Ankara, Turkey.

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.