Besnoitia sp. infection in a natural population of vizcachas (Lagostomus maximus, Rodentia) in Buenos Aires, Argentina

RUTH CWIRENBAUM; SANTIAGO ANDRES CORTASA; MARIA CLARA CORSO; ALFREDO DANIEL VITULLO; VERONICA BERTA DORFMAN; JULIA HALPERIN

Congreso; Reunión Anual de Sociedades de Biociencias 2020; 2020

SAIC, SAI, SAFIS

Our laboratory uses vizcachas as a model for reproductive endocrinology studies and we have often found abnormal cyst-like structures in ovaries. Our specimens come from a natural population at La Plata. A coccidian parasite that affected several domestic rabbits from a rabbit breeder in La Plata was the first report of a Besnoitia infection in Argentina. To evaluate whether vizcachas could also be host of this parasite, we examined histological sections of various female organs. Pinhead-sized tissue cysts were found in ovaries, adrenals, mammary glands, uterus, pituitary, brain, spleen and fascia. Either superficial or deep tissue cysts were simultaneously seen in several organs of the same animal. Cysts were found in both pregnant and non-pregnant females. Histologically, a thick wall made up of an outer layer of collagen fibers and an inner granular-looking layer surrounded each tissue cyst, which was packed with numerous bradyzoites and some host nucleated cells. Outside the cysts, host cellular structures showed normal appearance. Mammary gland acini of infected pregnant females showed normal morphology and the ovaries exhibited follicles in different stages despite the presence of cysts. These results indicate that infection with this parasite would not affect the reproductive process. The presence of cysts in brain areas could be indicative of the parasite ability to cross the blood-brain barrier whereas cysts in the embryonic organs suggest the same for the placental barrier. Based on a comparative morphological analysis with the tissue cysts exhibited by the naturally-infected rabbits of La Plata we identified ours as Besnoitia sp. This is the first report of L. maximus as a host for Besnoitia. Considering that bovine besnoitiosis is a serious problem affecting Middle East, Asia, Africa and Europe with significant economic losses, our report is highly relevant since the distribution map of L. maximus largely overlaps with that of Argentinian cattle.