Alcoholism and Strongyloides stercoralis: Daily Ethanol Ingestion Has a Positive Correlation with the Frequency of Strongyloides Larvae in the Stools

Abstract

Background

Significantly higher prevalence of Strongyloides stercoralis has been reported in chronic alcoholic patients. The aim of this investigation was to report the prevalence of Strongyloides larvae in stools of chronic alcoholic patients with known daily ethanol intake.

Methods

From January 2001 through December 2003 the results of fecal examinations and the daily ethanol intake were retrieved from the records of 263 chronic alcoholic and from 590 non-alcoholic male patients that sought health care at the outpatients unit of the University Hospital C A Moraes. Alcoholic patients were separated into four groups, with 150g intervals between the groups according to the daily ethanol intake.

Results

(a) The frequency of Strongyloides was significantly higher in alcoholic patients than in control group (overall prevalence in alcoholic 20.5% versus 4.4% in control group; p = 0.001). Even in the group with a daily intake of ethanol equal to or less than 150g the prevalence was higher than in control group, although non significant (9.5%, versus 4.4% in control group; p = 0,071); (b) the prevalence of Strongyloides in alcoholic patients rises with the increase of ethanol intake (Pearson's Correlation Coefficient = 0.956; p = 0.022), even in patients without liver cirrhosis (Pearson's Correlation Coefficient = 0.927; p = 0.037).

Conclusion

These results confirm and reinforce the hypothesis that chronic alcoholism is associated with Strongyloides infection, which is in direct relationship with the severity of alcoholism, independently of the presence of liver cirrhosis.

Author Summary

It has been reported that Strongyloides stercoralis infection is more prevalent in chronic alcoholic patients than in non alcoholics living in the same country. In a retrospective study on the prevalence of S. stercoralis infection in a large sample of alcoholic patients, we demonstrate that this prevalence is significantly higher than in non-alcoholic patients admitted at the same hospital. Moreover, the frequency of the parasite was in close relationship with the daily amount of ingested ethanol, even in the absence of liver cirrhosis, reinforcing the idea that chronic alcoholism is associated with increased susceptibility to Strongyloides infection. Beside the bad hygiene profile of alcoholic patients, which explains high risk for acquisition of the parasite, the high prevalence of S. stercoralis in alcoholics may be in relationship with other effects of ethanol on the intestinal motility, steroid metabolism and immune system, which could enhance the chance of autoinfection and the survival and fecundity of females in duodenum. In this way, the number of larvae in the stools is higher in alcoholic patients, increasing the chance of a positive result in a stool examination by sedimentation method.