ALCOHOLISM AND Strongyloides stercoralis: INVESTIGATION OF POSSIBLE FACTORS ASSOCIATED WITH THE GREATER PREVALENCE OF THE NEMATODE IN CHRONIC ALCOHOLISTS
Name: STEVEEN RIOS RIBEIRO
Publication date: 17/02/2017
Advisor:
Name |
Role |
|---|---|
| FAUSTO EDMUNDO LIMA PEREIRA | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| ALOÍSIO FALQUETO | Internal Examiner * |
| DANIEL CLAUDIO DE OLIVEIRA GOMES | Internal Examiner * |
| FAUSTO EDMUNDO LIMA PEREIRA | Advisor * |
| GUSTAVO ROCHA LEITE | External Examiner * |
Summary: Introduction. Strongyloides stercoralis (Bavay, 1876) is an intestinal nematode that can proliferate in the host by autoinfection, and persist for decades without further exposure to exogenous infection. The prevalence of the parasite is poorly known in the state. Higher prevalence of S. stercoralis in chronic alcoholic patients than in non-alcoholics, attended at the same hospital, has been reported, but there are doubts about if there is a greater exposure to the parasite or greater survival and fecundity of females in the duodenum would increase the chance of encountering larvae in the feces. Objectives. To evaluate: (a) the prevalence of S. stercoralis in the state on samples of schoolchildren aged 7 to 14 years and samples from patients attended at the different outpatient clinics of the Hospital C.A. Moraes (HUCAM) and Hospital Concórdia at Sta. Maria de Jetibá; (b) the prevalence of the parasite on samples of alcoholics and non-alcoholics in the Department of Gastroenterology of HUCAM and Hospital Concordia; (c) the number of S. stercoralis rabditoid larvae on stools of alcoholics and non-alcoholics patients; (d) the anti-S. stercoralis antibodies on serum and Treg lymphocytes (Treg) in peripheral blood in alcoholics and non-alcoholics; (e) the use of the conventional PCR method on stool samples of alcoholic and non-alcoholic patients, to confirm the difference in prevalence observed between the two groups. Methods. Stool samples were analyzed either by the Baermann-Moraes method or HPJ, and the larval count was made; the search for anti-S. stercoralis antibodies was done by ELISA (AccuDiagTM Strongyloides IgG ELISA Kit, Diagnostic Automation/Cortez Diagnostics, Inc, California, USA); Treg research on peripheral blood was done by flow cytometry; the PCR using probes to amplify specific ribosomal DNA sequences (Gene Bank access number: AF279916). Results. Prevalence of S. stercoralis was 0.47% on stool samples of schoolchildren and 1.17 on samples of the patients attending the two Hospitals. Higher prevalence of positive faecal examinations for S. stercoralis was evidenced on two samples of alcoholics and nonalcoholics by parasitological techniques and by DNA detection of the parasite on feces. The prevalence of positive serology for S. stercoralis was higher in alcoholics than in non-alcoholics. In alcoholics infected with S. stercoralis, the elimination of larvae on feces was significantly higher than in non-alcoholics; in S. stercoralis infected patients, alcoholics or not, and in alcoholics without Strongyloides infection, there was an increase in the peripheral blood Treg, compared to the nonalcoholic, non-infected control group; but with no difference between alcoholics and non-alcoholics infected groups. Conclusion. The state of Espírito Santo can be considered an endemic region for S. stercoralis. Higher prevalence of positive parasitological examinations in alcoholics, confirmed by PCR and a higher prevalence of anti-Strongyloides antibodies than in non-alcoholics, confirms that the abusive use of ethanol favors infection with S. stercoralis. Greater elimination of larvae on feces of alcoholics suggests a greater parasitic load or greater fecundity of females in the duodenum. Patients, alcoholics or not, with S. stercoralis and alcoholics without the parasite showed increased Treg in the peripheral blood, but the abusive use of ethanol did not potentiate this increase in alcoholics with the parasite.
