Intestinal damage in strongyloidiasis: the imbalance between cell death and proliferation

Effect of Bifidobacterium animalis on mice infected with Strongyloides venezuelensis

The administration of viable Bifidobacterium animalis was tested to induce resistance against Strongyloides venezuelensis infection in mice. Effects on parasite burden, worm length, egg output, and intestinal mucosal histology were evaluated. The oral administration of B. animalis, strain 04450B, starting 14 days before the inoculation of nematode larvae significantly decreased the worm burden and egg output. In probiotic treated animals, the percent reduction of adult worms in the intestine was of 33% and the reduction of egg production was of 21%, compared with those of the control group. The duodenum villous height and villous/crypt ratio were significantly higher in probiotic-treated mice, indicating that this group could be experiencing less intestinal damage. The present findings revealed that the administration of B. animalis for the amelioration of host response to nematode infections is biologically plausible and could have some potential for impacting public health. Meanwhile, further study is needed to delineate the nature and identity of the factor(s) involved in these beneficial effects.

Endoscopic and histopathological study on the duodenum of Strongyloides stercoralis hyperinfection

AIM: To investigate endoscopic and histopathological findings in the duodenum of patients with Strongyloides stercoralis (S. stercoralis) hyperinfection.

METHODS: Over a period of 23 years (1984-2006), we investigated 25 patients with S. stercoralis hyperinfection who had had an esophagogastroduodenoscopy before undergoing treatment for strongyloidiasis. The clinical and endoscopic findings were analyzed retrospectively.

RESULTS: Twenty-four (96%) of the patients investigated were under immunocompromised condition which was mainly due to a human T lymphotropic virus type 1 (HTLV-1) infection. The abnormal endoscopic findings, mainly edematous mucosa, white villi and erythematous mucosa, were observed in 23 (92%) patients. The degree of duodenitis including villous atrophy/destruction and inflammatory cell infiltration corresponded to the severity of the endoscopic findings. The histopathologic yield for identifying larvae was 71.4% by duodenal biopsy. The endoscopic findings of duodenitis were more severe in patients whose biopsies were positive for larvae than those whose biopsies were negative (Endoscopic severity score: 4.86 ± 2.47 vs 2.71 ± 1.38, P < 0.05).

CONCLUSION: Our study clearly demonstrates that, in addition to stool analysis, endoscopic observation and biopsies are very important. We also emphasize that S. stercoralis and HTLV-1 infections should be ruled out before immunosuppressive therapy is administered in endemic regions.