Frequency and cyst density of Sarcocystis spp. in the myocardium of alpacas (Vicugna pacos) according to sex and age in a province of the Peruvian Andes

Abstract Sarcocystis is a threat to food security in the Peruvian Andes. The Sarcocystis species that forms microcysts in the myocardium of alpacas is S. masoni n. sp. (known as "S. lamacanis"). There is a lack of current studies estimating the prevalence of this parasite in alpacas, although this information is crucial for the control and prevention of sarcocystosis. The aim of this study was to determine the frequency and cyst density of Sarcocystis masoni n. sp. in the myocardium of alpacas in Huancavelica, a province of the Andean region of Peru. Myocardial samples for histological analysis were taken from 104 alpacas slaughtered in an official abattoir in the area. All alpacas (100%) presented this parasite. About 44% (95% CI: 34.5-53.5%), presented from 31 to 45 microcysts per mm2 of myocardial histological slide (cyst density). Cyst density was significantly higher (p<0.05) as the age of the animals increased. In addition, cyst density was significantly higher (p<0.05) in 4- and 5-years-old males compared to females of the same age. These results confirm that myocardial sarcocystosis is highly endemic in alpacas in Peru.