Economic burden and biological drivers of carcass condemnation due to macroscopic sarcocystosis in Peruvian alpacas (Vicugna pacos).

Alpacas (Vicugna pacos) are essential for Andean food security and represent a sustainable global livestock alternative. However, macroscopic Sarcocystis infection leads to widespread carcass condemnation, devaluing this high-value protein source. This study quantified the biological determinants of sarcocystosis, the carcass condemnation prevalence, and the associated economic burden at the slaughterhouse through a stochastic modeling approach. Retrospective records (2021-2024) from two Andean locations (Ninacaca and Huancavelica) were analyzed to estimate economic impacts, while prospective data on age, sex, and weight identified risk factors for sarcocystosis. The financial burden at both study sites and a national projection was estimated using Monte Carlo simulations (10,000 iterations). The overall carcass condemnation prevalence was 62.6% (95% UI: 62.3-62.9%), with Huancavelica showing higher endemic stability (80.1%) than Ninacaca (25.6%), and females showing a higher likelihood of carcass condemnation (OR = 1.17, p = 0.009). Infection risk was strongly age-dependent, increasing over 500-fold in animals older than 3.5 years. Infected carcasses were 3.06 kg lighter than non-infected ones (95% CI: -3.36 to -2.75; p < 0.001). Despite limitations inherent to cross-sectional abattoir data, this weight difference provides a preliminary basis that warrants further longitudinal studies. Annual losses under a total condemnation scenario were USD 3.43 million for Huancavelica (95% UI: 3.28-3.59) and USD 533,618 for Ninacaca (95% UI: 510,890-556,459). These losses were reduced to USD 2.1 million and USD 319,380, respectively, when partial recovery via charqui processing was assumed. The national projection estimated a mean annual burden of USD 15.97 million (95% UI: 14.01-18.06), equivalent to USD 28.4 per slaughtered alpaca. These findings identify sarcocystosis as a structural driver of Andean rural poverty, highlighting the need for a national control strategy.