Field evaluation of a rapid diagnostic test to detect antibodies in human toxocariasis

Abstract

Human toxocariasis which is caused mainly by the larvae of Toxocara canis and Toxocara cati, is a worldwide zoonotic disease that can be a potentially serious human infection. The enzyme-linked immunosorbent assay (ELISA) using T. canis excretory-secretory (TES) antigens harvested from T. canis larvae is currently the serological test for confirming toxocariasis. An alternative to producing large amounts of Toxocara TES and improved diagnosis for toxocariasis is through the development of highly specific recombinant antigens such as the T. canis second stage larva excretory-secretory 30 kDa protein (recTES-30). The aim of this study was to evaluate the sensitivity and specificity of a rapid diagnostic kit (RDT, named as iToxocara kit) in comparison to recTES-30 ELISA in Serendah Orang Asli village in Selangor, Malaysia. A total of 133 subjects were included in the study. The overall prevalence rates by ELISA and RDT were 29.3% and 33.1%, respectively, with more positive cases detected in males than females. However, no association was found between toxocariasis and gender or age. The percentage sensitivity, specificity, positive predictive value and negative predictive value of RDT were 85.7%, 90.1%, 80% and 93.2%, respectively. The prevalence for toxocariasis in this population using both ELISA and RDT was 27.1% (36/133) and the K-concordance test suggested good agreement of the two tests with a Cohen's kappa of 0.722, P<0.01. In addition, the followed-up Spearman rank correlation showed a moderately high correlation at R=0.704 and P<0.01. In conclusion, the RDT kit was faster and easier to use than an ELISA and is useful for the laboratory diagnosis of hospitalized cases of toxocariasis.

Excretory/Secretory Metabolome of the Zoonotic Roundworm Parasite Toxocara canis

“…Diagnostic techniques include microscopic or macroscopic examination of the parasite, various DNA analysis techniques, and a variety of immune-based serological assays. Serological assays including enzyme-linked immunosorbent assay (ELISA), dot-ELISA, recTES-30 ELISA, and immunoblot are considered gold standard techniques for laboratory diagnosis of human Toxocara infection [3]. However, their sensitivities and cross-reactivities differ from place to place and they are often affected by the presence of infections by other parasites.…”

“…Covert toxocariasis is most frequently found in children and the clinical symptoms include fever, headaches, abdominal pain, cervical lymphadenitis and hepatomegaly. On the other hand, patients with visceral larva migrans are mostly asymptomatic, while patients with ocular larva migrans may have chronic inflammation and permanent eye damage [3]. Toxocara canis and T. cati are parasites of dogs and cats, respectively, but can accidentally infect humans and are the most common causes of human toxocariasis [4].…”

A Lateral Flow Rapid Test for Human Toxocariasis Developed Using Three Toxocara canis Recombinant Antigens

“…Bojanich et al 25 developed a dot-test ELISA and suggested that the several advantages it offered when compared with standard ELISA (i.e., test stability, low cost, and ease of use without the need for specialized equipment) made it the most suitable assay for epidemiological surveillance studies. More recently, Lim et al 26 reported on the development and evaluation of a lateral flow rapid test based on rTES-30, which they called iToxocara. In the present study, three recombinant proteins, rTES-26, rTES-30, and rTES-120, were used for the development of lateral flow dipsticks.…”

Toxocariasis in Children: An Update on Clinical Manifestations, Diagnosis, and Treatment

“…52 Immunochromatographic rapid diagnostic test based on the recombinant antigen recTES-30 is a rapid and easy to conduct test with high sensitivity as it can detect anti-Toxocara antibodies in children aged 1 to 10 years in spite of their low levels. 53…”