The diagnosis of Strongyloides stercoralis infections is routinely made by microscopic observation of larvae in stool samples, a low sensitivity method, or by other, most effective methods, such as the Baermann or agar culture plate methods. We propose in this paper a practical modification of Baermann method. One hundred and six stool samples from alcoholic patients were analyzed using the direct smear test, agar culture plate method, the standard Baermann method, and its proposed modification. For this modification the funnel used in the original version of the method is substituted by a test tube with a rubber stopper, perforated to allow insertion of a pipette tip. The tube with a fecal suspension is inverted over another tube containing 6 ml of saline solution and incubated at 37°C for at least 2 h. The saline solution from the second tube is centrifuged and the pellet is observed microscopically. Larva of S. stercoralis were detected in six samples (5.7%) by the two versions of the Baermann method. Five samples were positive using the agar culture plate method, and only in two samples the larva were observed using direct microscopic observation of fecal smears. Cysts of Endolimax nana and Entamoeba histolytica/dyspar were also detected in the modification of Baermann method. Data obtained by the modified Baermann method suggest that this methodology may helps concentrate larvae of S. stercoralis as efficiently as the original method.

The infection with Strongyloides stercoralis in 106 chronic alcoholic patients W8S evaluated, using agar plate culture (APC),Baermann method, and microscopic observation of direct smear of feces. Baermann method detected 6 (5.7%) cases: whereas by APC one case W8S not diagnosed (sensitivity of 83.3%), and only 2 were visualized by direct smear (sensitivity of 33.3%). Other intestinal parasites diagnosed were Endolimax nana (16%), Giardia 1amblia (7.3), Entamoeba coli (6.6%), Entamoeba histolytica (4.7%), hookworm (0.9%), Hymenolepis nana (0.9%), and Entamoeba hartmanni (0.9%). The overall prevalence of intestinal parasites in the patients studied was 30%. This value is relatively low. but it is in accordance with the national prevalence of 21% or less than 5% if only helminths are considerd. lt is important the comparison of hookworm and S. stercoralis infection in alcoholic patients, since both parasites have similar infection mechanisms, and our data showed a higher prevalence for the latter, that denote possible increasing risk for this infection.

Se evaluó la infección con Strongyloides stercoralis en 106 pacientes alcohólicos crónicos, usando el método de Baermann, el cultivo en plato de agar (CPA) y la observación microscópica de frotis de heces. El parásito fue observado en 6 (5,7%) casos. Todos diagnosticados por Baermann, 5 por CPA (sensibilidad = 83,3%), y solo 2 por el frotis directo (sensibilidad = 33,3%). Otros parásitos intestinales diagnosticados fueron Endolimax nana (16%), Giardia lamblia (7,3%), Entamoeba coli (6,6%), Entamoeba histolytica (4,7%), uncinarias (0,9%), Hymenolepis nana (0,9%) y Entamoeba hartmanni (0,9%). La prevalencia global de parásitos intestinales en los pacientes estudiados fue del 30%, un valor relativamente bajo; pero en concordancia con la prevalencia a nivelnacional que fue 21% o menor al 5% si sólo se consideran los helmintos intestinales. Además, es importante la comparación de las infecciones por uncinarias y S. stercoralis en pacientes alcohólicos, porque ambos parásitos tienen mecanismos de infección similares; pero nuestros datos muestran una mayor prevalencia para el último, lo que denota un posible incremento en el riesgo para esta infección en pacientes alcohólicos.