Biology subjects

Pelgrims, R.

Publications and source records attributed to Pelgrims, R..

3 recordsLinked to original sources

bioRxiv2026

Case report of unusual mortality of Egyptian fruit bat (Rousettus aegyptiacus) in northern Cyprus

We report an unusual mortality event affecting the isolated Egyptian fruit bat (Rousettus aegyptiacus) population in northern Cyprus, combining clinical admissions, microbiological findings, and roost surveys to assess magnitude and potential drivers. From January to June 2025, the Cyprus Wildlife Research Institute (CWRI) Wildlife Hospital received an unprecedented surge in admissions with 12 individuals (versus sporadic admissions in prior years), with high acute mortality: most bats arrived moribund and died within 12-24 hours. Clinical records noted localized purulent lesions and abscesses in a substantial fraction of cases. Bacteriological culture and PCR assays recovered Staphylococcus aureus from abscesses and skin swab samples in multiple individuals; isolates exhibited susceptibility to tested antibiotics. Necropsy sampling confirmed viable S. aureus in several specimens despite prolonged storage. Concurrent targeted surveys of ten known roosts in Feb-Mar 2026 documented marked declines at multiple historical sites, including reductions from hundreds to single-digit counts at formerly large colonies and the complete absence of bats at multiple roosts. No clear evidence of recent human disturbance, extreme weather anomalies, or reduced food availability was found; shotgun cartridges from historical hunting were present, but no direct anthropogenic cause was apparent. While S. aureus infections--seasonally concentrated in winter--are consistent with observed lesions and may have contributed to morbidity and mortality, causality for the population-level declines remains unknown, and other factors (toxins, unassessed pathogens, multi-factor stressors) cannot be excluded. Given the genetic isolation and conservation significance of the Cyprus Egyptian fruit bat population, these findings are concerning. We recommend urgent, coordinated longitudinal population monitoring, expanded pathogen surveillance including whole-genome sequencing of S. aureus isolates, toxicological screening, and development of a species recovery plan incorporating emergency response, habitat protection, and public outreach.

ecology↗

bioRxiv2019

Zebrafish dorsal habenula is required for updating learned behaviors

Operant conditioning requires multiple cognitive processes, such as learning, prediction of potential outcomes and decision making. It is less clear how interactions of these processes lead to the behavioral adaptations that allow animals to cope with a changing environment. We showed that juvenile zebrafish can perform conditioned place avoidance learning, with an improving performance across development. Ablation of the dorsolateral habenula (dlHb), a brain region involved in associative learning and prediction of outcomes, led to an unexpected improvement in performance and delayed memory extinction. Interestingly, while the control animals exhibited rapid adaptation to a changing learning rule, dlHb ablated animals failed to adapt. Altogether, our results show that the dlHb plays a central role in switching animals strategies while integrating new evidence with prior experience.

neuroscience↗

bioRxiv2019

Glia-neuron interactions underlie state transitions to generalized seizures

Brain activity and connectivity alter drastically during epileptic seizures. Throughout this transition, brain networks shift from a balanced resting state to a hyperactive and hypersynchronous state, spreading across the brain. It is, however, less clear which mechanisms underlie these state transitions. By studying neuronal and glial activity across the zebrafish brain, we observed striking differences between these networks. During the preictal period, neurons displayed a small increase in synchronous activity only locally, while the entire glial network was highly active and strongly synchronized across large distances. We observed that the transition from a preictal state to a generalized seizure leads to an abrupt increase in neuronal activity and connectivity, which is accompanied by a strong functional coupling between glial and neuronal networks. Optogenetic activation of glia induced strong and transient burst of neuronal activity, emphasizing a potential role for glia-neuron connections in the generation of epileptic seizures.

neuroscience↗