A Case of Visceral Larva Migrans Due toToxocara canisShowing Varied Manifestations

Relapse of toxocariasis after completion of four-week treatment with albendazole

Food-borne toxocariasis caused by the consumption of raw meat or liver has occasionally been reported from East Asia. We treated a 38-year-old Japanese man who was infected with Toxocara in China and underwent a four-week treatment with albendazole. The liver and lung lesions disappeared after the treatment, suggesting that the treatment was successful. One month after the end of the treatment, the patient relapsed, and albendazole was administered again for eight weeks. The patient has remained relapse-free for one year. Although toxocariasis can heal spontaneously, in some cases, such as the present case, the disease relapses even after long-term treatment. In conclusion, different durations of treatment are recommended by various guidelines, and the duration of treatment needs to be modified with each case, considering the response to the treatment.

Prevalence, Infection, and Risk to Human Beings of Toxocara canis in Domestic Food-Producing Animals

Toxocariasis is a significant food-borne zoonotic parasitic disease, and a range of birds and mammals are the paratenic hosts of Toxocara canis. The consumption of raw or undercooked meat and viscera of these paratenic hosts frequently leads to T. canis infection and the development of human toxocariasis. In this review, we will perform an analysis of relevant papers published in the National Center for Biotechnology Infrastructure database on the parasitism, migration, and infection of T. canis in chickens, pigeons, quail, pigs, cattle, sheep, and other food-producing animals, so as to make the public aware of the risk factors of human toxocariasis, improve the public's understanding of T. canis infection, and provide evidence for targeted prevention and control measures.

Serosurvey and associated risk factors of anti-Toxocara spp. antibodies in bovines from slaughterhouses of southeastern Brazil

BACKGROUND

Toxocariasis, caused by a nematode species of the genus Toxocara, has been described as one of the most prevalent zoonotic helminthiases worldwide. Human transmission may occur by ingesting Toxocara spp. larvae from raw or undercooked meat or organs; however, no comprehensive serosurvey study has been conducted to date investigating the role of cattle as paratenic hosts. The aim of the study reported here was to assess the prevalence of anti-Toxocara spp. antibodies and associated risk factors in bovines from two slaughterhouses located in Presidente Prudente, southeastern Brazil.

METHODS

Blood samples were collected and tested by indirect enzyme-linked immunosorbent assay (ELISA). Cattle farmers voluntarily responded to an epidemiologic questionnaire.

RESULTS

Overall, 213 of the 553 (38.5%) bovine samples were assessed as seropositive for anti-Toxocara spp. antibodies by indirect ELISA. Multivariate analysis revealed that the source of beef cattle and the presence of dogs or cats at the farm were associated with seropositivity. The use of feedlot systems was associated with lower likelihood of seropositivity.

CONCLUSIONS

These results indicate a high level of anti-Toxocara seropositivity in slaughterhouse cattle, with potentially contaminated meat posing an infection risk to humans. In addition, the presence of dogs and cats where the slaughtered beef cattle were raised was statistically associated with bovine seropositivity, probably due to the overlapping environment at the farm and the lack of pet deworming. The use of feedlot systems was a protective factor likely due to the absence of dog and cat contact, elevated feeding troughs that avoid contact with contaminated soil or grass, and younger age at slaughter of feedlot cattle. In summary, bovines may be used as environmental sentinels of Toxocara spp. contamination, and high seropositivity of slaughterhouse cattle may indicate a potential risk of human toxocariasis through the ingestion of raw or undercooked contaminated meat.

Toxocariasis of the Nervous System

PURPOSE

Toxocariasis is a helminthozoonosis caused by the infection of a human host by the larva of Toxocara spp., predominately involving Toxocara canis and Toxocara cati, which are common nematodes in dogs and cats, respectively. Human transmission occurs through contact with animals or by consumption of food contaminated with parasite's eggs. The purpose of this article is to review the current knowledge regarding human neurotoxocariasis.

METHODS

We conducted a systematic review of the existing literature concerning toxocariasis of the nervous system.

RESULTS

Clinical spectrum of human toxocariasis varies widely from a subclinical course to significant organ morbidity. Clinical course depends on parasitic load, the migration route of the larvae and host response. Human neurotoxocariasis is a relatively rare entity yet associated with severe sequelae. Manifestations include meningitis (usually eosinophilic), encephalitis, myelitis, cerebellar vasculitis, space-occupying lesion, behavioral abnormalities, and optic neuritis. Even though valid diagnostic criteria are lacking, neurotoxocariasis should be suspected in patients with neurologic symptoms and cerebrospinal fluid (CSF) pleocytosis with eosinophilia, positive serology for anti-Toxocara antibodies, in serum and/or CSF, sterile CSF and clinical improvement after antihelminthic treatment. Neurotoxocariasis is treated by benzimidazole components, most frequently albendazole, corticosteroids, or diethylcarbamazine.

CONCLUSION

Parasite larvae migrate through tissues and are able to reach the nervous system causing neurotoxocariasis. Its clinical spectrum varies and includes myelitis, meningoencephalitis, brain abscess, and vasculitis. Neurotoxocariasis should always be suspected in patients with neurologic symptoms accompanied by eosinophilia in blood and/or CSF. Early diagnosis and treatment could prevent long-term neurologic impairment.