Serodiagnosis of Toxocariasis by ELISA Using Crude Antigen of Toxocara canis Larvae

Abstract

Toxocariasis is a worldwide zoonosis caused by larvae of ascarid nematodes of dogs or cats, Toxocara canis or T. cati. Diagnosis of human toxocariasis currently relies on serology that uses T. canis excretory-secretory antigen to detect specific IgG antibodies by ELISA. We investigated the serodiagnostic efficacy of ELISA using crude antigen of T. canis larvae (TCLA). Serum specimens of 64 clinically confirmed toxocariasis, 115 healthy controls, and 119 other tissue-invading helminthiases were screened by ELISA using TCLA. The ELISA using TCLA showed 92.2% (59/64 patient samples) sensitivity and 86.6% (103/119) specificity. Its positive diagnostic predictivity was 78.7% and negative predictivity was 97.8%. No serum of healthy controls reacted but that of anisakiasis (45.5%), gnathostomiasis (19.2%), clonorchiasis (15.8%), sparganosis (11.1%), and cysticercosis (6.3%) cross-reacted. Immunoblot analysis on TCLA recognized antigenic proteins of 28- and 30-kDa bands in their dominant protein quantity and strong blotting reactivity. The present results indicate that the ELISA using our TCLA antigen is acceptable by the sensitivity and specificity for serodiagnosis of human toxocariasis. ELISA with TCLA is recommended to make differential diagnosis for patients with any sign of organ infiltration and eosinophilia.

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

“…However, as documented cases of toxocariasis are rarely described in Norway, we would not expect our study participants to have specific IgE towards Toxocara spp. We therefore focused on assessing IgG4 towards Toxocara spp., which is most commonly used for serodiagnosis of toxocariasis . Although we did not have data on specific IgE towards Ascaris or Toxocara in the present study, we cannot exclude the possibility that exposure to HDM or cockroach allergens may have influenced A. lumbricoides IgG4 seropositivity as observed in the present study.…”

“…We therefore focused on assessing IgG4 towards Toxocara spp., which is most commonly used for serodiagnosis of toxocariasis. 57 Although we did not have data on specific IgE towards Ascaris or Toxocara in the present study, we cannot exclude the possibility that exposure to HDM or cockroach allergens may have influenced A. lumbricoides IgG4 seropositivity as observed in the present study. However, we did not observe any association between Ascaris or Toxocara IgG4 and allergic sensitization (SPT or specific IgE) towards HDM, which is the most commonly described cross-reactive allergen with helminths.…”

“…However, somatic Toxocara spp. antigen ELISA is acceptable for detecting exposure to Toxocara spp . Moreover, we based our definition of exposure on elevated levels of Toxocara spp.…”

Detection of Specific Antibody Reactivity to Toxocara Larval Excretory-secretory Antigens in Asthmatic Patients (5-15 Years)

“…For example, Lim and his colleagues [26] suggested that toxocariasis is common but neglected by doctors mostly due to their lack of awareness. The second, toxocariasis is unaware to doctors and abandoned by lack of good routine diagnostic service in many regions [27]. The seroprevalence of anti- Toxocara antibodies was not significantly associated with the prior history of contact with dogs, consumption of unwashed fruits and vegetables, or use of cattle/sheep liver (P>0.05).…”

Ocular toxocariasis: clinical features, diagnosis, treatment, and prevention

“…The ELISA (Biokema-Affinity Products, Crissier-Lausanne, Switzerland) [28] at a serum titer greater than 1: 32 has 78% sensitivity for the detection of toxocariasis [29] and Hagler et al [30] suggested that a serum titer of 1: 8 is sufficient to support a diagnosis of ocular toxocariasis if the patient has signs and symptoms compatible with that disorder. In addition to the commercial ELISA kit, serodiagnosis by ELISA using crude antigen of toxocara larvae developed by researchers in Seoul National University in South Korea also showed acceptable diagnostic value with 92.2% sensitivity and 86.6% specificity [31]. It has been reported that recombinant antigens [32] can offer further solutions for serologic diagnosis by providing increased sensitivity and specificity compared to native excretory-secretory antigens.…”