Diagnostic Value of the Serum Anti-ToxocaraIgG Titer for Ocular Toxocariasis in Patients with Uveitis at a Tertiary Hospital in Korea

Abstract

PurposeThis study evaluated the prevalence of ocular toxocariasis (OT) in patients with uveitis of unknown etiology who visited a tertiary hospital in South Korea and assessed the success of serum anti-Toxocara immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) as a diagnostic test for OT.MethodsThe records of consecutive patients with intraocular inflammation of unknown etiology were reviewed. All participants underwent clinical and laboratory investigations, including ELISA for serum anti-Toxocara IgG. OT was diagnosed based on typical clinical findings. Clinical characteristics, seropositivity, and IgG titers were compared between patients diagnosed with OT and non-OT uveitis. The seropositivity and the diagnostic value of anti-Toxocara IgG was investigated among patients with different types of uveitis.ResultsOf 238 patients with uveitis of unknown etiology, 71 (29.8%) were diagnosed with OT, and 80 (33.6%) had positive ELISA results for serum anti-Toxocara IgG. The sensitivity and specificity of the ELISA test were 91.5% (65 / 71) and 91.0% (152 / 167), respectively. The positive predictive value of the serum anti-Toxocara IgG assay was 81.3%. Among patients with anterior, intermediate, posterior, and panuveitis, the prevalence rates of OT were 8.3%, 47.1%, 44.8%, and 7.1%, respectively; the seropositivity percentages were 18.1%, 47.1%, 43.7%, and 17.9%; and the positive predictive values were 38.5%, 95.8%, 92.1%, and 40.0%. The serum anti-Toxocara IgG titer also significantly decreased following albendazole treatment.ConclusionsOT is a common cause of intraocular inflammation in the tertiary hospital setting. Considering that OT is more prevalent in intermediate and posterior uveitis, and that the positive predictive value of the anti-Toxocara IgG assay is high, a routine test for anti-Toxocara IgG might be necessary for Korean patients with intermediate and posterior uveitis.

Designing and standardizing Toxocara serologic diagnostic kit and determining anti-Toxocara antibodies frequency in patients referred to health care centers in Urmia (northwest of Iran)

“…If these infective eggs (containing a L2 larva) are ingested by human, in the duodenum, the larva will hatch and find its route to the liver via the portal circulation, then from vascular channels to the lung systemic circulation. Eventually, larva will settle in various organs and tissues, including eye, brain, lungs, liver, and muscles, resulting in two major clinical syndromes of toxocariasis, visceral larva migrans (VLM) and ocular larva migrans (OLM) (Bae et al 2016;Despommier 2003;Fialho et al 2016;Fisher 2003). Other recognized clinical manifestations include neurological toxocarisis and occult toxocariasis (Mazur-Melewska et al 2015;Pawlowski 2001).…”

Prognosis for ocular toxocariasis according to granuloma location

“…The OT patients were predominately male, and the OT patients in this Korean population were older than those in Western countries, where OT mainly causes pediatric uveitis due to contamination of the environment or infection from pets. [ 4 , 10 , 14 , 27 – 30 ] We suggest that these differences in sex and age distribution are the result of differences in the route of infection. Some adult males in Korea eat raw cow’s liver or meat, believing it to be good for ocular health, which may have been the cause of OT in previous studies.…”

“…[ 6 – 8 ] However, recent studies from Asia have reported a higher prevalence than expected in uveitis patients, whose infection may have involved ingestion of infected raw cow liver or meat. [ 9 – 14 ]…”

“…[ 16 , 17 ] Although some studies revealed that ELISA test could have cross reactivity with other helminthes,[ 18 , 19 ] another study reported that the sensitivity and specificity were 91.5% and 91.0%, respectively. [ 20 ] Another study proved the usefulness of additional use of aqueous humor in ELISA test to improve accuracy of diagnosis. [ 21 ]…”

Ocular toxocariasis caused by toxocara canis in an adult woman. Case report

“…(7) For this reason, differential diagnosis should be made with other ocular granulomatous diseases such as ocular toxoplasmosis, sarcoidosis, tuberculosis and fungal infections. (3,15) Since leukocoria and strabismus are the two most common signs of retinoblastoma, it is also necessary to perform a differential diagnosis with this neoplasm. (7,13,16) The patient described in this case did not present any of those ocular alterations.…”