Comparative Risk Analysis of Two Culicoides-Borne Diseases in Horses: Equine Encephalosis More Likely to Enter France than African Horse Sickness.

The researchers have studied the probabilities of African Horse Sickness and Equine Encephalosis, two vector-borne diseases, entering France. They found Equine Encephalosis to be more likely to enter through an infectious host while African Horse Sickness through an infected vector. They also propose distinct protective measures for both diseases.

Objective of the study

• The primary aim of this research was to investigate and compare the likelihood of two vector-borne viral diseases – African Horse Sickness (AHS) and Equine Encephalosis (EE) – entering France. They used stochastic spatiotemporal models to predict the potential entry routes of these viruses.

Methodology

• The researchers utilized stochastic spatiotemporal models that estimate the chance of virus entry into France. They examined this over three consecutive years, from 2010 to 2012, with particular emphasis on how the probabilities varied with seasons and different regions.
• Two main pathways for virus entry were considered: the importation of live-infected animals and the importation of infected vectors (midges of the Culicoides genus).

Findings

• The study found that both AHS and EE showed the same patterns of seasonal and regional differences in their entry probabilities into France. However, EE had a significantly higher probability of entry than AHS.
• Moreover, the most likely route of virus entry was different for each disease. AHS was more likely to enter through infected vectors, while EE was more likely to enter through live-infected animals (hosts).

Proposed Protective Measures

• The research presented different protective measures for the two diseases. For AHS, the most efficient prevention method was implementing vector protection on all imported animals from low-risk regions. This means taking steps to prevent any vectors like midges from infecting the animals before they are brought into the country.
• For EE, the greatest reduction in virus entry probability was achieved by implementing quarantine measures for horses imported from both EU and non-EU countries. This would involve keeping the imported animals isolated for a period to ensure they are not infected before entering the population.

Implications

• The models developed in this study suggest specific actions for reducing the risk of these diseases entering France. Not only could these steps protect the national equine industry, but they could also provide guidance for addressing similar risks in other countries.
• Moreover, these findings may also be useful in implementing risk-based surveillance, aiding in the effective monitoring and prevention of these potentially devastating diseases.