Evaluation of immunologic tests in the diagnosis of Giardia duodenalis and Cryptosporidium spp., Honduras

Abstract

Background: We know no data about evaluation of immunologic tests for improved diagnosis of Giardia duodenalis and Cryptosporidium spp., worldwide important etiologic agents of diarrhea, in Honduras. Objectives: To evaluate two immunologic tests for the diagnosis of Giardia and Cryptosporidium spp. and determine their applicability compared to microscopy results. Methodology: Descriptive transverse study. One hundred and sixty-four stool samples from the Parasitology Service (PS), Hospital Escuela (HE) and 67 samples from a health center were analyzed with an immunochromatographic rapid test (2013); 60 samples from PS were tested by an immunoenzymatic test ELISA (2019-2020). Microscopic routine protocol examination included direct smear in saline and Lugol solutions, trichrome stain and carbol fuchsine acid resistant modified stain (ARM). Results: Either immunologic test recognized more Giardia (6.7% vs 4.5%) and Cryptosporidium (3.7% vs 0.7%) than microscopy in 134 samples at HE with the rapid immunochromatographic assay, as well as in 67 samples at CSAS (14.9% vs. 7.5% for Giardia and 0.7% for Cryptosporidium with immunological test). Of 60 samples analyzed by ELISA test in HE, 31.7% was positive for Giardia compared to 18.3% in the direct smear and 23.3% with trichrome stain; Cryptosporidium spp. was 6.7% positive compared to 3.3% with ARM stain. Discussion: Immunologic tests significantly improved Giardia and Cryptosporidium microscopic diagnosis; however, other publications utilizing similar tests presented inconclusive results. High cost would limit their use for pediatric and immunocompromised patients in hospitals, complementing microscopy. Public health laboratories must strengthen diagnostic capacity.