# Swine Influenza Virus Introduction in Pig Farms: A Semi-Quantitative Risk Assessment in Northern Italy

## TL;DR

This study assesses the risk of swine influenza virus introduction in 22 pig farms in northern Italy using biosecurity and location data to prioritize surveillance efforts.

## Contribution

A semi-quantitative risk assessment method was applied to classify pig farms based on biosecurity and geography for influenza virus introduction.

## Key findings

- All farms had the highest risk for buildings and access control due to poor visitor management.
- Fifteen farms showed medium risk for personnel biosecurity due to PPE use issues despite training.
- The method helps identify high-risk farms for targeted surveillance and mitigation strategies.

## Abstract

Influenza viruses are a major health priority worldwide. Pigs can be infected with both human and avian strains, increasing the risk of emergence of new strains with pandemic potential. Therefore, risk-based surveillance for the early detection of new viruses is needed. In our study, we classified 22 commercial pig farms in northern Italy in terms of likelihood of influenza virus introduction, based on their biosecurity system and geographical location. We used a semi-quantitative risk assessment method to calculate risk priority codes, indicating increasing levels of risk for biosecurity criteria for the evaluated farms. Then, an overall risk index was calculated including a geographical risk indicator. The highest risk for all the farms regarded biosecurity related to buildings and access control, due to poor visitor control. Medium risk was obtained in fifteen farms for biosecurity related to personnel, with most of the farms compliant with training on biosecurity, but with some critical points related to the use of personal protective equipment. The method allowed the identification of farms at higher risk, which is crucial to implement risk-based surveillance and to apply strategies aimed at risk mitigation.

Swine influenza is a viral zoonotic respiratory disease of pigs threatening both animal and human health due to its pandemic potential. We conducted a semi-quantitative risk assessment to classify 22 commercial pig farms in northern Italy in terms of the likelihood of introduction of influenza, evaluating their biosecurity systems and geographical locations. We used a modified Failure Mode and Effect Analysis (FMEA) to calculate Risk Priority Codes (RPCs), indicating increasing risk levels (from 1 to 5) for six biosecurity criteria: (A) personnel, (B) animal management, (C) shelter management, (D) animal transport, (E) materials management, and (F) buildings and access control. Then, an overall risk index, including the geographical risk, was calculated to obtain the final risk ranking of the farms. All farms obtained the highest risk level (RPC = 5) for criterion F (buildings and access control), mostly due to poor control of visitor access. Fifteen farms scored a medium risk level (RPCs = 3) for criterion related to personnel due to some weaknesses in the use of personal protective equipment, although 90% of personnel had recent biosecurity training. In an endemic context, risk assessment helps identify high-risk farms, supporting surveillance for early detection of new influenza strains.