Acute schistosomiasis diagnosis: a new tool for the diagnosis of schistosomiasis in a group of travelers recently infected in a new focus of Schistosoma mansoni

Rafaella Fortini Queiroz Grenfell,Alba Otoni,Carlos Maurício De Figueiredo Antunes,Paulo Marcos Zech Coelho,Izabela Voieta,Áureo Almeida De Oliveira,Vanessa Silva-Moraes,Edward Oliveira,Watson Martins,José Roberto Lambertucci,Cristina Toscano Fonseca,Sandra Costa Drummond,Eduardo Ribeiro De Oliveira

doi:10.1590/0037-8682-0064-2012

Abstract

The diagnosis of schistosomiasis mansoni on early stages of infection is important to prevent late morbidity. A simple, cheap, sensitive and specific assay for routine diagnosis of schistosome infection based on the detection of specific IgG for schistosomula tegument antigens (ELISA-SmTeg) was developed by our group. We describe here an acute outbreak involving a travel group of 80 individuals from a non-endemic area of the State of Minas Gerais, Brazil. These individuals were in contact with a freshwater pool where Biomphalaria glabrata was found. Results obtained from our new methodology were compared to IgG antibody titers against soluble worm antigenic preparation (SWAP) by ELISA and, also to parasitological examination, nuclear magnetic resonance and clinical findings. ELISA-SmTeg was capable of detecting 64 positive cases among the 80 individuals participating at the survey with a positivity ratio of 80% and a higher sensitivity than ELISA-SWAP that was only sensitive for 56% of positive cases. Besides, a significant correlation was found for the severity of the infection and the specific IgG titers against SmTeg. Our data showed that ELISA-SmTeg might serve as the initial diagnostic tool for acute stages of the infection in community-based helminth control programs or for the surveillance of individuals from non-endemic areas.

Highlights

The diagnosis of schistosomiasis mansoni on early stages of infection is important to prevent late morbidity
Schistosoma mansoni infection was defined as exposure to the freshwater pool plus one of the following criteria: presence of eggs in faecal samples, immunoglobulin G (IgG) antibody titers by ELISA using adult worm antigens, myeloradiculopathy detected by nuclear magnetic resonance, and/or symptoms compatible with acute schistosomiasis
We could see that patients that was diagnosed as negative by ELISA-soluble worm antigenic preparation (SWAP), but presented all the clinical symptoms compatible with acute schistosomiasis (28/80) (35%), presented lower IgG titers for SmTeg in comparison to group 2 (p=0.002)

Summary

Introduction

The diagnosis of schistosomiasis mansoni on early stages of infection is important to prevent late morbidity. Methods: We describe here an acute outbreak involving a travel group of 80 individuals from a non-endemic area of the State of Minas Gerais, Brazil. A significant correlation was found for the severity of the infection and the specific IgG titers against SmTeg. Conclusions: Our data showed that ELISA-SmTeg might serve as the initial diagnostic tool for acute stages of the infection in community-based helminth control programs or for the surveillance of individuals from non-endemic areas. The acute symptomatic schistosomiasis that may appear 3 to 7 weeks after an exposure and is characterized by cough, fever, anorexia, abdominal pain and headaches In this phase, the inflammatory reaction is well established and involves predominantly Th1 bias, when immunoglobulin levels are elevated in the serum[2] and hypereosinophilia. Hepatosplenic, schistosomal myeloradiculopathy and acute forms with the latter being a main indicator of schistosomiasis severity[3,4]

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Conclusion