Biology subjects

Weinberg, M.

Publications and source records attributed to Weinberg, M..

7 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↗

bioRxiv2023

Neural responses to social cues in the accessory olfactory bulb are altered by context and experience.

Social interaction enhances evolutionary fitness by enabling efficient communication of physiological information between individuals. Semiochemicals, that convey socially relevant physiological information, are detected by the vomeronasal organ (VNO) which projects directly to the accessory olfactory bulb (AOB). Mitral and tufted (M/T) neurons in the AOB convey this information from the AOB to a network of brain regions particularly devoted to processing social information and affecting social behavior. The dynamics of social behaviors are shaped by both context and experience. However, our understanding of how alterations in behavior, triggered by the same social cues, correlate with moment-to-moment fluctuations in neural activity within social circuits remains limited. Here, we investigate how context and experience alter the sensory-driven activity of AOB M/T neurons using fiberphotometry and find that the context in which a stimulus is presented can be as important for determining the strength of response as the identity of the stimulus itself.

neuroscience↗

bioRxiv2023

Spatial and single-cell transcriptomics illuminate bat immunity and barrier tissue evolution

The Egyptian fruit bat displays tolerance to lethal viruses and unique dietary adaptations, but the molecular basis for this is poorly understood. To this end, we generated detailed maps of bat gut, lung and blood cells using spatial and single-cell transcriptomics. We compared bat with mouse and human cells to reveal divergence in genetic programs associated with environmental interactions and immune responses. Complement system genes are transcriptionally divergent, uniquely expressed in bat lung and gut epithelium, and undergo rapid coding-sequence evolution. Specifically in the tip of the gut villus, bat enterocytes express evolutionarily young genes while lacking expression of genes related to specific nutrient absorption. Profiling immune stimulation of PBMCs revealed a monocyte subset with conserved cross-species interferon expression, suggesting strong constraints to avoid an excessive immune response. Our study thus uncovers conserved and divergent immune pathways in bat tissues, providing a unique resource to study bat immunity and evolution.

genomics↗

bioRxiv2023

A comparative analysis of the antiviral response in two bat species reveals conserved and divergent innate immune pathways

Bats host a range of viruses that cause severe disease in humans without displaying clinical symptoms to these infections. The mechanisms of bat adaptation to these viruses are a continuous source of interest but remain largely unknown. To understand the landscape of bat antiviral response in a comprehensive and comparative manner, we studied this response in two bat species - the Egyptian fruit bat and the insectivore Kuhls pipistrelle, representing the two major bat subordinal clades. We profiled the transcriptional response to dsRNA - that triggers a rapid innate immune response - in skin fibroblasts from a large cohort of replicates from each bat species, using RNA-sequencing, and compared bat response with responses in primates and rodents. Both bat species upregulate a similar set of genes, many of which are known to be involved in the antiviral response across mammals. However, a subset of these genes is transcriptionally divergent in response between the two bat species. These transcriptionally divergent genes also evolve rapidly in coding sequence across the bat clade and have particular regulatory and functional characteristics, including specific promoter architectures and association with expression programs thought to underlie tolerance and resistance in response to viral infection. In addition, using single-cell transcriptomics, we show that transcriptionally divergent genes display high expression variability between individual cells. A focused analysis of dsRNA-sensing pathways further points to significant differences between bat and human in basal expression of genes important for triggering antiviral responses. Finally, a survey of genes recently lost or duplicated in bats points to a limited set of antiviral genes that have undergone rapid gene loss or gain in bats, with the latter group resulting in paralogs displaying divergence in both coding sequence and expression in bat tissues. Our study reveals a largely conserved regulatory program of genes upregulated in response to viral infection across bats and other mammals, and points to a set of genes that evolved rapidly in bats through multiple evolutionary mechanisms. This divergence can contribute to bat adaptation to viral infection and provides directions to understanding the mechanisms behind it.

evolutionary biology↗

bioRxiv2022

Seasonal challenges of tropical bats (Rousettus aegyptiacus) in temperate zones

Egyptian fruit bats (Rousettus aegyptiacus) manage to survive and flourish in a large geographic range despite the variability of natural and anthropogenic conditions in this range. To examine the challenges faced by free-ranging R.aegyptiacus living at the northern edge of their distribution, we performed a retrospective analysis of [~]1500 clinical cases reported by a bat rescue NGO over 25 months, from all over Israel. All cases of injured or stranded bats were evaluated and categorized according to date, place, sex, age, and etiology of the morbidity. The analysis of the data showed an increase in all types of morbidity during the wintertime, with more than twice the number of cases in comparison with the summertime, over two consecutive years. Moreover, we found that the number of abandoned pups peaks during spring till autumn when adult morbidity is minimal. We characterize two prominent types of previously undescribed morbidity in R.aegyptiacus, one in the form of bacterial illness, and the other associated with feet deformation which affects bats in addition to major anthropogenic-related threats related to synanthropic predators. We analyze the reasons driving winter morbidity and conclude that winter weather and specifically low temperature best explains this morbidity. We hypothesize that R.aegyptiacus, a fruit-bat of tropical origin is facing major seasonal difficulties near the northern edge of its distribution, probably limiting its further spread northward.

ecology↗

bioRxiv2020

Sick Bats Stay Home Alone: Social distancing during the acute phase response in Egyptian fruit bats (Rousettus aegyptiacus)

Along with its many advantages, social roosting imposes a major risk of pathogen transmission. How social animals, and especially free-ranging mammals, reduce this risk is poorly documented. We used lipopolysaccharide injection to imitate bacterial sickness in both a captive and a free-ranging colony of an extremely social, long lived mammal - the Egyptian fruit bat. We monitored behavioral and physiological responses using an arsenal of methods, including on-board GPS and acceleration, video, temperature and weight measurements, and blood samples. Sick-like bats exhibited an increased immune response, as well as classical illness symptoms including fever, weight loss, anorexia, and lethargy. Notably, they also isolated themselves from the group by leaving the social cluster and avoiding contact. Free-ranging individuals ceased foraging outdoors for at least two nights. Together, these sickness behaviors demonstrate a strong, integrative immune response which promotes recovery of infected individuals while protecting their group members from transmission of pathogens, and at the same time, reducing spillover events outside the roost.

zoology↗

bioRxiv2017

Who is the host of the host-associated microbiome? Colony-level dynamics overshadow individual-level characteristics in the fur microbiome of a social mammal, the Egyptian fruit-bat

In the first longitudinal study of bat microbiomes, we find that unlike the pattern described in humans and other mammals, the prominent dynamics in Egyptian fruit bats fur microbiomes are those of change over time at the level of the colony as a whole. Thus, on average, a pair of fur microbiome samples from different individuals in the same colony collected on the same date are more similar to one another than a pair of samples from the same individual collected at different time points. This pattern suggests that the whole colony may be the appropriate biological unit for understanding some of the roles of the host microbiome in social bats ecology and evolution. This pattern of synchronized colony changes over time is also reflected in the profile of volatile compounds in the bats fur, but differs from the more individualized pattern found in the bats gut microbiome.

ecology↗