Chickens bred extensively as sentinels from soil contamination by Toxocara

Deglycosylation of Excretory-Secretory Antigens of the Second-Stage Larvae of Toxocara cati Improves Its Efficacy in the Diagnosis of Human Toxocariasis

Background

Toxocariasis is an important zoonotic infection, especially in tropical areas. One of the significant challenges in the serodiagnosis of human toxocariasis is the cross-reaction of Toxocara antigens with other parasites due to their relatively similar glycan structures. Removing the glycan structure from Toxocara excretory-secretory (TES) antigens may increase the efficacy of these antigens in the diagnosis of toxocariasis. The current study aimed to assess the efficacy of deglycosylated Toxocara cati excretory-secretory (dTES) antigens for the serodiagnosis of human toxocariasis.

Methods

Toxocara ES antigens were prepared from T. cati second-stage larvae and deglycosylated using sodium hydroxide (NaOH). The TES antigens, along with the dTES antigens, were used in an ELISA as well as a western blotting system for the detection of anti-Toxocara antibodies. Sera samples collected from 30 confirmed cases of toxocariasis, 30 patients with other diseases, and 30 healthy subjects were evaluated by both systems.

Results

The sensitivity of TES and dTES ELISA for the diagnosis of human toxocariasis was 96.67% (95% CI = 82.78-99.92) and 93.33% (95% CI = 77.93-99.18), respectively, while the specificity of dTES (88.33%; 95% CI = 77.43-95.18) increased significantly compared to the TES (80.00%; 95% CI = 67.67-89.22). The sensitivity of both antigens was 100% (95% CI = 88.43-100) by the western blotting system. Moreover, the specificity of TES and dTES antigens was 95% (95% CI = 86.08-98.96) and 98.33% (95% CI = 91.06-99.96), respectively, when using the western blotting system.

Conclusion

Results of the current study indicate that the chemical removal of the glycan epitopes of T. cati ES antigens significantly reduces cross-reactivity rates with other parasitic infections. Considering the findings of the present study, the dTES antigens seem to be suitable antigens for the serodiagnosis of human toxocariasis.

Detection of Toxocara species larvae in four Iranian free-range broiler farms

BACKGROUND

The epidemiology of Toxocara canis and Toxocara cati in food animals, associated products, and their zoonotic potential are poorly understood. A cross sectional study was designed to determine the prevalence of Toxocara spp. larvae from free-range broiler chickens in traditional farms using conventional techniques and molecular method. Eight-hundred tissue samples including liver, gizzard, lungs and heart were collected from 200 chickens belonging to different regions of Zanjan Province, Iran and were processed by conventional and molecular methods.

RESULTS

Out of 800 chicken tissues, 49 samples (6.1%) were positive for nematode larvae. Polymerase chain reaction was performed to identify species-specific of Toxocara larvae. The findings showed that 10.5% (21 out of 200) chickens were infected with Toxocara species, so that 57.1% (12 out of 21) of the samples were positive for Toxocara canis and 42.9% (9 out of 21) of the samples were positive for Toxocara cati.

CONCLUSION

Considering the significant contamination/infection of free-range broiler chickens with Toxocara larvae, the consumption of chicken meat and viscera, especially liver and gizzards, can play an important role in the transmission of infection to humans. Prevention and control measures focused on regular deworming of dogs and cats, increasing public awareness of Toxocara infection are recommended.

Human Toxocariasis: 2010 to 2020 Contributions from Brazilian Researchers

This is a review of the published contributions made by Brazilian researchers between 2010 and 2020 on the natural history of human toxocariasis and the effects of human toxocariasis on nonhuman paratenic hosts.