Human toxocariasis

Abstract

Parasitic nematodes of the genus Toxocara are socioeconomically important zoonotic pathogens. These parasites are usually directly transmitted to the human host via the faecal-oral route and can cause toxocariasis and associated complications, including allergic and neurological disorders. Although tens of millions of people are estimated to be exposed to or infected with Toxocara spp, global epidemiological information on the relationship between seropositivity and toxocariasis is limited. Recent findings suggest that the effect of toxocariasis on human health is increasing in some countries. Here we review the salient background on Toxocara and biology, summarise key aspects of the pathogenesis, diagnosis, and treatment of toxocariasis, describe what is known about its geographic distribution and prevalence, and make some recommendations for future research towards the prevention and control of this important disease.

Prevalence of Toxocara and Toxascaris infection among human and animals in Iran with meta-analysis approach

“…In total, seroprevalence data integration in epidemiological investigations is not reasonable for several reasons, comprising sampling disparities, antigen preparation, and quality, different cutoff levels, cross-reactivity especially in the tropics were polyparasitism exist and inability to explicitly distinguish the infection by various Toxocara spp. Therefore, expanding our evidence based on human Toxocara infection would be corroborated by a better understanding of parasite biology, in particular, the immune evasion mechanism of larvae, and utilization of advanced, species-specific diagnostic tools [30].…”

“…Toxocara/Toxascaris infection in human populations is considered as a chronic parasite in nature which is distributed worldwide, particularly in tropical underdeveloped countries [28]. Several risk factors are supposed to play a major role in Toxocara/Toxascaris distribution among the human population, consisting of habitation in rustic areas, soil contact, consuming the undercooked meat of the infected paratenic host, insufficient and unhygienic water repositories, poor housing and low education as well [29][30][31][32]. Furthermore, owing to the adventurous nature of children, such as tasting any objects, eating soil and/or earthworms and being in the vicinity of dogs and cats, they are considered as a substantial risk group regarding toxocariasis [4,33].…”

Zoonotic helminth exposure and risk of allergic diseases: A study of two generations in Norway

“…Why zoonotic Toxocara spp. infections do not confer the protection associated with natural helminth infections is not known, but may possibly be due to Toxocara spp.‐secreted immune regulatory products being active against dog and cat immune responses and not against human . Therefore, the Toxocara spp.…”

Seroprevalence and risk factors for Toxocara infection among children in a rural community in Fars province, southern Iran

“…Human becomes infected by the ingestion of Toxocara eggs in the contaminated soil, vegetables or the consumption of raw meat of paratenic hosts contained Toxocara larvae . Human toxocariasis is often asymptomatic; however, it may be presented as ocular larva migrans (OLM), visceral larva migrans (VLM), nervous or covert toxocariasis . Covert toxocariasis is considered as the most common form of the disease with symptoms including wheezing, cough, fever, and headache with or without eosinophilia .…”

“…1 Human toxocariasis is often asymptomatic; however, it may be presented as ocular larva migrans (OLM), visceral larva migrans (VLM), nervous or covert toxocariasis. 2 Covert toxocariasis is considered as the most common form of the disease with symptoms including wheezing, cough, fever, and headache with or without eosinophilia. 1 Children are more prone to infection because of playing in the playground centres or sandboxes contaminated with Toxocara eggs.…”