Clinical Studies in Non-Dysenteric Intestinal Amebiasis

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  • Gorgas Memorial Laboratory, Panama, R. of P.


In the present clinical investigation only cases of intestinal amebiasis in which there was neither a present nor a past history of dysentery were studied. The cases comprised both symptom-less carriers of E. histolytica and infected individuals with complaints of varying severity. Control observations were made whenever feasible. Only those symptoms and signs were ascribed to E. histolytica after other possible causes had been ruled out. In all, 216 cases of non-dysenteric amebiasis were studied, of which 100 were found to have symptoms.

  1. 1.A study of the occurrence of symptomatology in a selected group of 106 apparently healthy men harboring E. histolytica showed 46 or 43.4 per cent to have symptoms. A control group of 108 cases negative for intestinal protozoa revealed but 8 or 7.4 per cent to have complaints. Of the 106 cases of amebiasis only 13.2 per cent of the complaints were of any appreciable severity.
  2. 2.Of 236 individuals harboring various intestinal protozoal species, but not E. histolytica, the percentage with symptoms was similar to that found in the non-parasitized group, with the exception of Dientamoeba fragilis in which 27.3 per cent of 44 cases presented symptoms. Similarly, some of the flagellates presented higher percentages than the control. An explanation of this apparent pathogenicity was offered.
  3. 3.A study of the blood findings in 61 cases of apparently healthy carriers of E. histolytica showed no significant differences from the results obtained in a control group of an equal number of individuals not harboring the parasite.
  4. 4.Despite the apparent trivial nature of the complaints presented by most of the cases in an ambulatory group, it was found by a study of various hospitalized groups that a considerable number of non-dysenteric amebic infections are severe enough to require hospitalization. In 47 such cases the disease picture was so obscure that only the finding of the parasite in the stool led to the proper diagnosis, and in these, specific anti-amebic treatment gave good results where other methods had failed.
  5. 5.A study of the nature of complaints revealed these to be primarily referable to the gastro-intestinal tract, yet without blood and mucus in the stools and usually without bowel abnormalities which might suggest an amebic process. Complaints referable to both upper and lower gastro-intestinal tracts appeared with equal frequency. Complaints referable to other systems were seldom encountered. Chronicity, recurrency and mildness of the symptoms were characteristic features.
  6. 6.A symptom-complex simulating subacute or chronic appendicitis was the most commonly observed syndrome in this series of non-dysenteric cases of amebiasis.

Author Notes

Medical Corps, United States Navy.