Quantitative risk assessment of rabies being introduced into mainland France through worldwide noncommercial dog and cat movements

Risk of rabies reintroduction into the European Union as a result of the Russo-Ukrainian war: A quantitative disease risk analysis

AIMS

The importation of rabid animals poses a continual threat to rabies freedom in the European Union (EU). Following the Russian invasion of Ukraine in 2022, the European Commission eased the rules on companion animal importations for Ukrainian refugees through derogations to the EU Pet Travel Scheme (EU PETS). As Ukraine remains endemic for canine rabies, this paper aimed to quantitatively assess whether the change in regulations affected the risk of rabies introduction to the EU.

METHOD AND RESULTS

Transmission pathways for both EU PETS and derogations to this scheme were considered, as well as the scenarios of 100% compliance and reduced compliance within both schemes. Stochastic modelling was performed via a Monte Carlo simulation to calculate the median and 95% confidence intervals of the annual risk of rabies entry and the years between rabies entries into the EU. Following 100% compliance, the derogation scheme posed a significantly lower risk at a value of 3.63 × 10-3 (CI 95% 1.18 × 10-3-9.34 × 10-3) rabies entries per year in comparison to EU PETS where the risk was 4.25 × 10-2 (CI 95% 1.44 × 10-2-9.81 × 10-2). Despite a significantly lower risk as compared to EU PETS under 100% compliance, the derogation scheme was more sensitive to a reduction in compliance which resulted in a 74-fold increase in risk. Given this, even under reduced compliance, the annual risk remained lower under the derogation scheme, although this was not statistically significant.

CONCLUSION

The findings of this study suggest that a 4-month period of quarantine, as modelled for the derogation scenario, could reduce the annual risk of rabies entry. This scheme may present a viable solution for the management of companion animal influxes in future crises.

Retrospective analysis of sero-prevalence and bait uptake estimations in foxes after oral rabies vaccination programmes at European level: Lessons learned and paths forward

Rabies caused by the Classical Rabies Virus (Lyssavirus rabies abbreviated RABV) in the European Union has been close to elimination mainly thanks to Oral Rabies Vaccination (ORV) campaigns targeting wildlife (primarily red foxes). ORV programmes co-financed by the European Commission include a monitoring-component to assess the effectiveness of the ORV campaigns at national level. This assessment is performed by a random collection of red foxes in the vaccinated areas with control of antibodies presence by serological analysis and control of bait uptake by detection of biomarkers (tetracycline incorporated into the baits) in the bones and teeth. ORV programmes aim to a vaccine coverage high enough to immunize (ideally) 70 % of the reservoir population to control the spread of the disease. European Union (EU) programmes that led to almost elimination of rabies on the territory have been traditionally found to have a bait uptake average of 70 % (EU countries; 2010-2020 period) while the seroconversion data showed an average level of 40 % (EU countries; 2010-2020 period). To better understand variations of these indicators, a study was been set up to evaluate the impact of several variables (linked to the vaccination programme itself and linked to environmental conditions) on the bait uptake and the seroconversion rate. Thus, pooling data from several countries provides more powerful statistics and the highest probability of detecting trends. Results of this study advocate the use of a single serological test across the EU since data variation due to the type of test used was higher than variations due to field factors, making the interpretation of monitoring results at EU level challenging. In addition, the results indicates a negative correlation between bait uptake and maximum temperatures reached during ORV campaigns questioning the potential impact of climatic change and associated increase of temperatures on the ORV programmes efficiency. Several hypotheses requesting additional investigation are drawn and discussed in this paper.