Diagnostic Performance of Kato Katz Technique and Point-of-Care Circulating Cathodic Antigen Rapid Test in Diagnosing Schistosoma mansoni Infection in HIV-1 Co-Infected Adults on the Shoreline of Lake Victoria, Tanzania.

Humphrey Mazigo,Jorg Heukelbach

doi:10.3390/tropicalmed3020054

Abstract

Background: The diagnostic performance of the Kato Katz (KK) technique and the point-of-care circulating cathodic antigen (POC-CCA) test in detecting S. mansoni infection in the presence of the human immunodeficiency virus-1 (HIV-1) infection has remained inconclusive. The present cross-sectional survey compared the diagnostic performance of the KK technique and the POC-CCA test in diagnosing S. mansoni infection in an adult population co-infected with HIV-1 in northwestern Tanzania. Methods: Single urine and stool samples from 979 adults were screened for S. mansoni infection using both the KK technique and POC-CCA tests. To compare the performance of the two diagnostic tests a combined artificial gold standard was created, based on either an egg-positive KK technique or a POC-CCA-positive test. Results: Based on the KK technique, the prevalence of S. mansoni was 47.3% (463/979, 95% CI: 44.2–50.4), as compared to 60.5% by the POC-CCA test (592/979; 95% CI: 57.4–63.5). The overall sensitivity and specificity of the POC-CCA test were 92.5% (95% CI: 89.4–94.9) and 73.3% (95% CI: 69.6–76.8), respectively. In the HIV-1 seropositive group, the sensitivity and specificity of the POC-CCA test were 78.1% (95% CI: 60.0–90.7) and 45.9% (95% CI: 35.8–56.3). Using a combined gold standard, the sensitivity of the POC-CCA test increased to >90% in both subgroups whereas that of the KK technique in the HIV-1 seropositive group was low (49.5%; 95% CI: 39.6–59.5). Conclusion: In the presence of HIV-1 co-infection, the KK technique attained a very low sensitivity. The POC-CCA test offers the best option for the rapid screening of S. mansoni infection in communities with a high prevalence of HIV-1 infection.

Highlights

Intestinal schistosomiasis caused by Schistosoma mansoni remains one of the Neglected Tropical Diseases that is highly endemic in communities living along the shorelines of Lake Victoria in northwestern Tanzania [1,2]
The study was performed at Sangabuye, Kayenze, Igalagala, and Igombe, four villages located at the southern shore of Lake Victoria, in the Ilemela district (32–34◦ E and 2–4◦ S), Mwanza region, northwestern Tanzania [10,22]
The main findings from this study indicate that the point-of-care circulating cathodic antigen (POC-cathodic antigen (CCA)) test is more sensitive than the parasitological Kato Katz (KK) technique in detecting S. mansoni infection among the general study population, in the human immunodeficiency virus-1 (HIV-1)/S. mansoni co-infected population

Summary

Introduction

Intestinal schistosomiasis caused by Schistosoma mansoni remains one of the Neglected Tropical Diseases that is highly endemic in communities living along the shorelines of Lake Victoria in northwestern Tanzania [1,2]. KK technique sensitivity can be increased by repeating stool samples to be collected and tested over consecutive days [7]. This adds more cost to the control programs and may result in the withdrawal of study participants [7]. The present cross-sectional survey compared the diagnostic performance of the KK technique and the POC-CCA test in diagnosing S. mansoni infection in an adult population co-infected with HIV-1 in northwestern Tanzania. Using a combined gold standard, the sensitivity of the POC-CCA test increased to >90% in both subgroups whereas that of the KK technique in the HIV-1 seropositive group was low (49.5%; 95% CI: 39.6–59.5). The POC-CCA test offers the best option for the rapid screening of S. mansoni infection in communities with a high prevalence of HIV-1 infection

Methods

Discussion

Conclusion