Stool antigen immunodetection for diagnosis of Giardia duodenalis infection in human subjects with HIV and cancer

Abstract

Human infection with the protozoan parasite Giardia duodenalis is one the most common parasitic diseases worldwide. Higher incidence rates of giardiasis have been reported from human subjects with multiple debilitating chronic conditions, including hypogammaglobulinemia and common variable immunodeficiency (CVID). In the current study, stool specimens were collected from 199 individuals diagnosed with HIV or cancer and immunocompetent subjects. The sensitivity of microscopy-based detection on fresh stool preparations, trichrome staining and stool antigen immunodetection for the diagnosis of G. duodenalis were 36%, 45.5% and 100%, respectively when compared with a highly sensitive stool-based PCR method as the gold standard. Further multilocus molecular analyses using glutamate dehydrogenase (gdh) and triose phosphate isomerase (tpi) demonstrated that the AI genotype of G. duodenalis was the most prevalent, followed by the AII genotype and mixed (AI+B) infections. We concluded that stool antigen immunodetection-based immunoassays and stool-based PCR amplification had comparable sensitivity and specificity for the diagnosis of G. duodenalis infections in these populations. Stool antigen detection-based diagnostic modalities are rapid and accurate and may offer alternatives to conventional microscopy and PCR-based diagnostic methods for the diagnosis of G. duodenalis in human subjects living with HIV or cancer.

Combined Mini-Parasep SF and Nanogold Immunoassay Show Potential in Stool Antigen Immunodetection for Giardiasis Diagnosis

“…In recent years, there is an increased rate of using stool antigen immunodetection-based assays for the detection of Giardia infections in humans, widely in diagnostic laboratories in both underdeveloped and developing countries and this is because of their higher sensitivity compared to conventional microscopic diagnostic methods. Antigen detection modalities have rapid diagnostic capabilities and comparable sensitivity and specificity to those of stool-based PCR methods for the diagnosis of giardiasis 5 .…”

Multilocus sequence typing of Giardia duodenalis genotypes circulating in humans in a major metropolitan area

“…In this study, tpi assemblage-specific PCR assays showed a high prevalence (45.2%) of mixed infection of A and B assemblage in Tehran isolates, but less than reported in Malaysia (64%) ( 36 ), although greater than in Belgium (32.4%) ( 32 ) using the same primers. Co-infection by assemblage A and B has been previously reported in Iran based on PCR-RFLP of the gdh locus ( 21 , 25 , 43 , 45 ).…”

Parasitic infections in hematopoietic stem cell transplant recipients

“…8 Unlike in immunocompetent patients, microscopic detection of parasites in stool has low sensitivity in immunocompromised patients. 17 Furthermore, the fact that cysts are often excreted intermittently or sometimes released in numbers too small to be detected also decreases the sensitivity of this test. 12 In immunocompromised patients with HIV, stool antigen immunodetection-based modalities have been shown to have higher sensitivity than stool microscopy.…”

“…12 In immunocompromised patients with HIV, stool antigen immunodetection-based modalities have been shown to have higher sensitivity than stool microscopy. 17 However, in some cases confirmatory testing via duodenal biopsy and aspiration might be needed in patients having persistent GI symptoms. 9 Treatment of giardia is typically metronidazole, nitazoxanide, or paromomycin.…”