[Toxocariasis in a 5-year-old boy--manifesting as bronchial asthma and behavioral disorder]

Toxocara Awareness Among Medical Practitioners in Saudi Arabia

Human toxocariasis is a zoonotic infection with global and regional impacts. Worldwide it is underestimated and clinically overlooked. Medical practitioners are generally unaware of the extent of the resulting disease spectrum. The objective of the study was to assess knowledge and disease awareness among medical practitioners in Aseer, south-western Saudi Arabia. A questionnaire addressing knowledge about the parasite, its visceral larva migrans and the disease spectrum generated was used to interview participants. The study included 285 participants. In answer to the question what is toxocara, only 27%, answered correctly that it is a nematode, paediatricians being the majority. With regard to years of experience among participants, 56.8% of those who answered correctly had less than 5-year experience, as opposed to 35.4% for those with more than 10-year experience. The cumulative awareness about the disease manifestations and spectrum, i.e. those who knew, was less than 30% across specialties and years of experiences. Lack of awareness regarding Toxocara infection and the disease spectrum it can generate is evident. The consequence for such lack of knowledge within our practising medical community is simply unacceptable as it might translate into misdiagnosis and consequently misguided treatment.

Toxocariasis and the clinical spectrum

Toxocara canis and T. cati are among the most widely distributed helminthic species in the world with a high zoonotic impact. Millions of people are infected^a and hundreds of thousands are suffering from toxocarosis, a disease encompassing four different entities: larva migrans visceralis (VLM) syndrome, ocular larva migrans (OLM) syndrome, covert toxocarosis (covT), common toxocarosis (comT) and neurotoxocarosis (NT). Toxocara infections in humans may remain clinically inapparent but may also induce severe diseases. This contribution gives a synoptic overview of the most important historical, clinical, diagnostic and therapeutical aspects of toxocarosis in humans.

Manifestation of toxocariasis in children with neuroblastoma treated with autologous hematopoietic transplants

Toxocariasis was diagnosed in 3 out of 22 children (14%) treated in our center with high-dose chemotherapy and autologous hematopoietic stem cell transplantation (HSCT). The patients were coming from rural areas in the southeastern Poland and did not present any clinical symptoms of toxocariasis upon admission to the hospital. Although no neurological and ophthalmological abnormalities were noticed, the atypical form of toxacariasis was diagnosed based on elevated eosinophils counts, positive serological tests, and biochemical symptoms of liver damage. The authors conclude that toxocariasis should be taken into consideration in the differential diagnosis of eosinophilia in children undergoing high-dose chemotherapy and HSCT, especially if they are coming from rural areas.

Toxocara-infestations in Austria: a study on the risk of infection of farmers, slaughterhouse staff, hunters and veterinarians

A total of 585 persons from several occupational groups (farmers, slaughterhouse staff, hunters, veterinarians) exposed to Toxocara infestations and 50 persons of a control group were tested for the presence of specific antibodies to the Toxocara canis antigen using an enzyme-linked immunosorbent assay and a western blot. Farmers showed the highest seroprevalence (44%), followed by veterinarians (27%), slaughterhouse staff (25%) and hunters (17%), whereas only 2% of the individuals of the control group were seropositive. Thus, the risk to Toxocara infestation is 39, 18, 16 and 9 times higher for farmers, veterinarians, slaughterhouse staff (some workers were part-time farmers) and for hunters, respectively, when compared to the control group. The main source of infection in rural areas seems to be (roaming) farm cats and dogs that have not been dewormed. The results are discussed with a view to potential risk factors and preventive measures, in terms of veterinary and human medicine.

Association of autoantibodies against small nuclear ribonucleoproteins (snRNPs) with symptomatic Toxocara canis infestation

Several studies have demonstrated the occurrence of autoantibodies in the course of infestations with helminth parasites and a number of target proteins have been identified. Sera from patients suffering from toxocarosis, a disease caused by the parasitic roundworm Toxocara canis, and from healthy individuals were tested for autoantibodies by immunofluorescence and immunoblot assays using HEp-2 cells as antigen. A considerable proportion of the sera from patients with toxocarosis-associated symptoms were autoantibody-positive, with a speckled staining pattern in the immunofluorescence test (62%) and with anti-snRNP reactivity in the immunoblot assay (98%). In contrast, significantly fewer sera from asymptomatic individuals scored positive in these assays (18% in the immunofluorescence test, P < 0.005; 24% in the immunoblot, P < 0.005). Although the causative link between Toxocara infestation and the occurrence of autoantibodies is still unclear, our results show that increased amounts of autoantibodies are associated with clinical symptoms of inflammation. Thus a serum test for autoantibodies in toxocarosis patients might be a valuable gatekeeper assay for the decision for or against anti-inflammatory treatment.

Treatment of ocular toxocariasis with albendazole

The purpose of this study was to evaluate the efficacy of combined albendazole and steroid treatment for uveitis caused by Toxocara canis in immunocompetent patients. Five patients (7 eyes) with ocular larva migrans syndrome (OLM) were used in this study. Toxocariasis was suspected based on clinical manifestations and confirmed by anti-toxocara IgG and Western blot analysis. Systemic albendazole (adults: 800 mg b.i.d.; children: 400 mg b.i.d.) was given in conjunction with steroids. Visual acuity before and after therapy, inflammatory response, side effects and toxicity were evaluated. Treatment resulted in an improved visual acuity in all patients. Mean initial Snellen visual acuity was 20/40, and mean final acuity was 20/20. There were no recurrences of uveitis throughout the observation period (average: 13.8 months; range: 3 days to 24 months). These findings suggest that albendazole, in combination with systemic steroids, is a useful regimen to treat ocular larva migrans syndrome.