Abstract
Purpose:
Previous studies of prevalence of ocular lesions secondary to toxoplasma gondii infection revealed that 20% of patients patients attending ophthalmic offices at the center east region of Misiones have toxoplasmic retinal scars. Most of the patients with toxoplasmic retinochoroiditis (63%) have German or Eastern European ancestry. A small mbya aborigine community of 150 people called Tamandua is located in the above mentioned region. The purpose of this study is to evaluate the prevalence of toxoplasmic retinochoroidal lesions in Mbya aborigines from the center region of Misiones, Argentina
Methods:
With the consent of the cacique (community leader) and each patient, a complete eye examination including, visual acuity, autorefractometry, anterior biomicroscopy, and indirect ophthalmoscopy were performed in aborigines with decrease visual acuity. Antibodies against toxoplasma gondii were screen by indirect hemaglutination and results were later confirmed by the Sabin Feldman dye test.
Results:
From all aborigines that underwent ophthalmic examination only two presented retinochoroidal scars compatible with toxoplasma gondii retinochoroidal infection (n=52). One of them had active intraocular inflammation at the moment of examination. Sixty seven percent of the examined aborigines tested positive for toxoplasma gondii antibodies when samples were tested by Sabin Feldman .
Conclusions:
We detect a difference in the prevalence of toxoplasmic retinochoroidal lesions between the Caucasian versus the Mbya populations on the center-east region of Misiones. There are some possible explanations that can describe the low prevalence of toxoplasmic retinochoroidal lesions in mbya aborigenes: First, Mbya aborigines and their ancestors have been in contact with the local toxoplasma parasite strains for more than 1000 years while European immigrants not. Second, there are no cats in the majority of Mbya communities, hence it is possible that mbyas got in contact with low amounts of tissue cysts, and much less frequently with oocysts.More studies are needed to determine the causes in the difference in toxoplasmic retinochoroidal prevalence between both populations
Keywords: 734 toxoplasmosis •
704 retinochoroiditis •
746 uveitis-clinical/animal model