Unusual Mortality Event in Egyptian Fruit Bat Population in Northern Cyprus
Researchers documented a surge in sick and dying Egyptian fruit bats in northern Cyprus between January and June 2025, alongside sharp declines at multiple known roost sites. The affected population is genetically isolated, and Staphylococcus aureus infections were detected in several individuals, though the root cause of the broader population decline remains unknown. The findings raise conservation concerns and prompted calls for urgent monitoring and expanded pathogen surveillance.
From January to June 2025, the Cyprus Wildlife Research Institute received 12 Egyptian fruit bat admissions — an unprecedented number compared to prior years — with most animals arriving moribund and dying within 12 to 24 hours. Clinical examinations revealed purulent lesions and abscesses in a substantial fraction of cases, and bacteriological testing identified Staphylococcus aureus in multiple individuals, with isolates remaining susceptible to standard antibiotics. Follow-up roost surveys conducted in February and March 2026 found dramatic declines at several historically large colonies, with some sites dropping from hundreds of bats to single digits and others showing complete absence. Investigators found no clear evidence of recent human disturbance, extreme weather, or food scarcity, though historical hunting cartridges were present at some sites. The authors caution that while S. aureus infections — which tend to cluster in winter — are consistent with the observed lesions, they cannot confirm this as the sole or primary driver of the population-level decline, and other factors such as toxins or undetected pathogens remain possible. Because the Cyprus population is genetically isolated, the authors describe the situation as particularly concerning and recommend longitudinal monitoring, whole-genome sequencing of bacterial isolates, toxicological screening, and development of a formal species recovery plan.
What's missing
The study notes several of its own key limitations: roost survey data were collected roughly 8–14 months after the initial mortality event, making it difficult to establish a direct temporal link between the hospital admissions and the observed population declines. Toxicological screening of carcasses had not yet been completed at the time of publication, leaving chemical or pesticide exposure unassessed. Whole-genome sequencing of S. aureus isolates — which could clarify whether a novel or particularly virulent strain is involved — was recommended but not yet performed. The baseline population size of the Cyprus Egyptian fruit bat population prior to the event is not precisely established, limiting quantification of overall losses.
What different sources said
- bioRxivCenter
Case report of unusual mortality of Egyptian fruit bat (Rousettus aegyptiacus) in northern Cyprus
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