Concerns are rising in France following reports of a patient infected with hantavirus after a cruise, but the Rhône region is no stranger to the virus. A case was already detected in the region in 2024, and infected rats have been found in Lyon’s Parc de la Tête d’Or.
Hantavirus in France: A National Overview
Between 2005 and 2024, a total of 2,046 cases of hemorrhagic fever with renal syndrome (HFRS) were diagnosed in mainland France by the National Reference Centre (CNR) for hantaviruses (Institut Pasteur). These figures highlight the recurrent presence of hantavirus infections across the country.
A Confirmed Case of Seoul Virus in the Rhône
The confirmed case in the Rhône region dates back to 2024 and involved an infection with the Seoul virus (SEOV). According to Santé publique France, the strain detected in this patient is similar to strains circulating in wild rats captured in Lyon’s Parc de la Tête d’Or.
An article titled “Evolution and genetic characterization of Seoul virus in wild Rattus norvegicus rats from an urban park in Lyon, France (2020-2022)” details that SEOV is an orthohantavirus primarily carried by rats. In humans, it can cause hemorrhagic fever with renal syndrome (HFRS).
Rats in Parc de la Tête d’Or Tested Positive
The study, conducted by researchers who sampled rats in Parc de la Tête d’Or between 2020 and 2022, aimed to provide essential information for implementing SEOV surveillance strategies. “We performed a comprehensive serological and molecular characterization of SEOV in Rattus norvegicus in a highly frequented urban park in a large city (Lyon, France),” the study explains.
The researchers observed low genetic structuring of wild rat populations across the city of Lyon. However, one specific sampling site within the park (a building established in 2021) exhibited significant genetic differentiation and warranted particular attention. The study confirmed the circulation of SEOV among rats in the park, showing a high seroprevalence rate of 17.2% and a strong genetic similarity to a strain previously identified in Lyon in 2011.
Surveillance as an Early Warning System
This study confirmed the continuous circulation of the Seoul virus in a heavily visited urban park, indicating a present risk of human transmission. The authors suggest that “implementing surveillance of this virus could constitute an effective early warning system and help prepare risk-based interventions.”
Given the significant gene flow observed between rat populations in the park and those in the rest of the city, the study recommends that SEOV surveillance be conducted at a city-wide level. This broader approach would provide a more comprehensive understanding of the virus’s spread and potential risks to the urban population.
Public Health Implications and Future Actions
The presence of hantavirus in an urban environment like Lyon, particularly within a popular public park, underscores the importance of ongoing public health monitoring and preventative measures. Authorities are urged to consider these findings in their public health strategies to mitigate potential outbreaks and ensure public safety.
The findings from Lyon contribute to the broader understanding of hantavirus epidemiology in urban settings, providing valuable data for public health officials not only in France but also internationally. The continuous surveillance and characterization of such zoonotic diseases are crucial for timely responses and effective disease control.
The current concern surrounding the hantavirus case involving a cruise ship passenger further emphasizes the need for vigilance and robust public health infrastructure to address emerging and re-emerging infectious diseases. The lessons learned from the Lyon study can inform strategies for other urban areas facing similar challenges.
Source: https://actu.fr/auvergne-rhone-alpes/lyon_69123/hantavirus-a-lyon-un-cas-dans-le-rhone-en-2024-des-rats-infectes-au-parc-de-la-tete-d-or_64258536.html
