Animal health in Argentina is facing a major epidemiological milestone following the recent confirmation by the National Service for Agri-Food Health and Quality (SENASA) of the first cases of classical scrapie in imported breeding sheep. The affected animals, identified in farms located in the provinces of Santa Fe and Entre Ríos, had been imported from Paraguay between 2021 and 2022. This finding highlights the complexity of Transmissible Spongiform Encephalopathies (TSEs) and the critical importance of post-entry surveillance systems.
Pathogenesis and Diagnosis: The Challenge of the Prion Protein
Scrapie is a progressive, fatal neurodegenerative disease that affects small ruminants. Unlike conventional viral diseases, its etiology is based on prions, abnormal isoforms of normal cellular proteins in the central nervous system that induce pathological conformational changes.
One of the main challenges for veterinary clinicians is its long incubation period, which allows asymptomatic animals to pass initial clinical inspections. In this outbreak, the animals showed no compatible symptoms, and the disease was detected only after natural death through active surveillance.
Initial diagnosis was performed using a screening ELISA test and later confirmed by Western Blot at a reference laboratory in Spain. This method confirmed the presence of the classical strain, previously absent in the country.
Risk Management and Adaptation of International Trade
The detection of this disease results in an immediate change in the country’s sanitary status, directly impacting export protocols. In response, SENASA has begun adapting international certifications in line with the guidelines of the World Organisation for Animal Health (WOAH).
The goal is to mitigate trade disruptions through the classification of “safe commodities.” Under international standards, products such as wool, tallow, collagen, and embryos remain eligible for trade.
Ovine meat is considered safe provided that specified risk materials (SRM) are strictly removed. For other products, such as live animals or dairy products, additional mitigation measures are proposed in accordance with international recommendations for countries with varying sanitary conditions.
Sanitary Safety and Public Health
It is essential for veterinary professionals to clearly communicate that scrapie is not a zoonotic disease. There is no scientific evidence of risk to public health, either through direct contact with infected animals or through the consumption of derived products.
Additionally, it has been confirmed that the disease does not affect cattle nor is it transmitted through bovine products.
Containment and Surveillance
Containment of these outbreaks currently depends on movement restrictions in affected production units and intensified epidemiological surveillance.
For the veterinary community, this event reinforces the importance of immediate mandatory reporting when detecting suspicious neurological signs, in order to ensure the resilience of the national animal health system.