Molecular typing of Strongyloides stercoralis in Latin America, the clinical connection

REPETTO SILVIA ANALÍA; QUARROZ BRAGHINI JUAN; RISSO MARIKENA GUADALUPE; BATALLA ESTELA; STECHER DANIEL; SIERRA MARIELA; BURGOS JUAN MIGUEL; RADISIC MARCELO; GONZALEZ CAPPA STELLA MARIS; RUYBAL PAULA

Congreso; MEEGID XV 2021: 15th International Conference on Molecular Epidemiology and Evolutionary Genetics of Infectious Diseases; 2021

Strongyloidiasis is a soil-transmitted, intestinal parasitic neglected disease caused by the nematode genus Strongyloides. We previously suggested that the parasitological cure after ivermectin administration is unlikely. The aim of this study was to analyze the variability of a 404 bp region of the cox1 (cox1.404) mitochondrial gene from 41 Latin-American samples in a clinical context including epidemiological, diagnosis and follow-up variables. A prospective, descriptive, observational study was also conducted to evaluate clinical and parasitological evolution after ivermectin treatment of 29 patients infected with Strongyloides stercoralis. Reactivation of the disease was defined both by clinical symptoms appearance and/or direct larvae detection from 30 days after treatment.The analysis of the 41 stool samples described ten cox1.404 haplotypes organized in two clusters (C1 and C2). HP24 and HP93 were the most frequent haplotypes in our patient?s population, distributed in American and Asian continents and cluster founders in median-joining network analysis (C1 and C2, respectively).Clinical presentation (intestinal, severe, cutaneous, and asymptomatic), immunological status and eosinophil count were not associated with specific haplotypes or clusters. Nevertheless, presence of C1 haplotypes during diagnosis increased the risk of reactivation with an OR of 7.51 (CI 95% 1.38-44.29, p=0.026). In contrast, reactivation probability was 83 times lower if C2 was detected (OR=0,17, CI 95% 0.02-0.80, p=0,02). Hence, I152V mutation, associated with C2, could be related with a lower mitochondrial energy metabolism in S. stercoralis reducing the odds of intra-host cycle reactivation. Overall, this is the first analysis of S. stercoralis cox1 diversity in the clinical context. Haplotype/cluster determination could assist in the management of strongyloidiasis clinical evolution. C1 identification during diagnosis suggests the need to increase the frequency of medical examination compared to other genetic variants. In contrast, C2 and its protective role would avoid the irrational use of ivermectin as prophylaxis in immunocompromised patients.