Abir Monastiri

Bats are major reservoir hosts of coronaviruses (CoVs), yet the ecological mechanisms governing CoV circulation and cross-species transmission remain poorly understood, particularly in Europe. Here, we investigated the diversity, host associations, and interspecific transmission dynamics of alpha- and betacoronaviruses in European bats using an integrated phylogenetic and network-based approach. We analysed 835 guano samples collected from 31 bat roosts in Catalonia and the Balearic Islands (Spain) between 2020 and 2024, encompassing 14 bat species from three families. CoV RNA was detected in 18.9% of samples, with five alphacoronavirus and two betacoronavirus subgenera identified. Virus–host networks were highly structured and non-random, with strong modularity and specialization, and a small subset of bat species occupying central connector roles. Notably, we report the first confirmed detection of sarbecoviruses in Miniopterus schreibersii , expanding their known host range beyond Rhinolophidae, and identify merbecoviruses in Rhinolophus euryale for the first time. Phylogenetic and seasonal patterns suggest that these associations reflect ecologically mediated cross-species transmission facilitated by mixed roosting, synchronized colony phenology, and spatial overlap. Our findings reveal greater permeability of coronavirus host boundaries than previously assumed and highlight multi-species bat colonies and ecological networks as key contexts for understanding and anticipating viral emergence.

Toscana phlebovirus (TOSV) and Sicilian phlebovirus (SFSV) are endemic in the Mediterranean area where they are transmitted to humans by infected sandflies. Vertebrates of several species have been postulated to act as reservoirs of these viruses, but convincing evidence is still awaited. Among them, bats have been suggested, however documented evidence is lacking. Here we tested a total of 329 bats belonging to eight species collected from twelve localities in southern Spain for the presence of neutralizing antibodies specific to TOSV and SFSV. Positive sera were detected in Schreiber’s long-fingered bat (Miniopterus schreibersii), mouse-eared Myotis (Myotis myotis), European free-tailed bat (Tadarida teniotis), and common serotine (Eptesicus serotinus) with the latter showing the highest prevalence rates for SFSV (22.6%) and TOSV (10%). There was no difference between females and males. Results suggest that bats are not likely to play a major role in the natural cycle of these two sandfly-borne phleboviruses. However, large breeding colonies of bats can be used as sentinels for surveillance of the presence of such viruses in a given locality. In addition, capture–recapture studies should be initiated in order to understand better the dynamics of TOSV and SFSV in bat populations.

A West Nile virus (WNV) outbreak occurred in Tunisia between mid-July and December 2012. To assess the epidemiological features of the WNV transmission cycle, human cerebrospinal fluid samples from...