Overdiagnosis of amebiasis in children with dysentery

• Published in: Archivos argentinos de pediatría Vol. 107; no. 6; pp. 510 - 514
• Main Authors: Beltramino, Juan Carlos, Sosa, Horacio, Gamba, Natalia, Busquets, Natalia, Navarro, Lucas, Virgolini, Stella, Ricardo, Omar
• Format: Journal Article
• Language: Spanish
• Published: Argentina 01-12-2009
• Subjects: Adolescent; Argentina - epidemiology; Child; Child, Preschool; Diagnosis, Differential; Dysentery - epidemiology; Dysentery - parasitology; Dysentery, Amebic - complications; Dysentery, Amebic - diagnosis; Dysentery, Amebic - epidemiology; Enzyme-Linked Immunosorbent Assay; Female; Humans; Infant; Male; Prevalence; Argentina
• ISSN: 1668-3501
• DOI: 10.1590/S0325-00752009000600007

There are morphologically identical amebaes, but with differences that can distinguish them; one as pathogenic: Entamoeba histolytica, and the other: Entamoeba dispar, as inoffensive. That brought the new hypothesis that many of the cases treated as amebiasis, weren't so.
To identify E. hystolitica in patients with dysentery, supposed to be caused by amebae.
Transversal and observational study performed between March 2005 and November 2007 in the city of Santa Fe, Argentina. Stools from children aged 2 months to 15 years-old with dysentery and direct exams with E. hystolitica/ dispar, were studied with ELISA to detect the adhesin of E. histolytica (adhesin Eh). Permanent stains for amebae were done as well as stool cultures. Clinical data were charted.
75 children were studied; 35 were male and 40, female, with a median age of 3 years-old. All of them presented diarrhea with leucocyte, 73% macroscopic blood on stool and 27% detectable on the microscope. Elisa Eh was positive in 21; 3 cases had hematophagous trophozoites. In 15 stool cultures were found: S. flexneri S2 type in 5 cases. Other parasites: 6 (Blastocystis homini 5). In 54 adhesin Eh was negative, 19% of the coulouring detected E. dispar. From 44 stool cultures: S. flexneri S2 type was detected in 13, Shigella sp in 1, C jejuni 5, other: 3. Other parasites: 12 (Blastocystis homini 9).
In this group of children with "amebic dysentery", half of them developed invasive bacteriae and only 28% had E. histolytica on stools; that means that the prevalence of positive cases in the population could be 18% to 38% [CI 95% (0.179; 0.381)].