Reproductive seasonality of the Egyptian fruit bat (Rousettus aegyptiacus) at the northern limits of its distribution

Sosuga Virus Detected in Egyptian Rousette Bats (Rousettus aegyptiacus) in Sierra Leone

Sosuga virus (SOSV), a rare human pathogenic paramyxovirus, was first discovered in 2012 when a person became ill after working in South Sudan and Uganda. During an ecological investigation, several species of bats were sampled and tested for SOSV RNA and only one species, the Egyptian rousette bat (ERBs; Rousettus aegyptiacus), tested positive. Since that time, multiple other species have been sampled and ERBs in Uganda have continued to be the only species of bat positive for SOSV infection. Subsequent studies of ERBs with SOSV demonstrated that ERBs are a competent host for SOSV and shed this infectious virus while exhibiting only minor infection-associated pathology. Following the 2014 Ebola outbreak in West Africa, surveillance efforts focused on discovering reservoirs for zoonotic pathogens resulted in the capture and testing of many bat species. Here, SOSV RNA was detected by qRT-PCR only in ERBs captured in the Moyamba District of Sierra Leone in the central region of the country. These findings represent a substantial range extension from East Africa to West Africa for SOSV, suggesting that this paramyxovirus may occur in ERB populations throughout its sub-Saharan African range.

Advances in understanding bat infection dynamics across biological scales

Over the past two decades, research on bat-associated microbes such as viruses, bacteria and fungi has dramatically increased. Here, we synthesize themes from a conference symposium focused on advances in the research of bats and their microbes, including physiological, immunological, ecological and epidemiological research that has improved our understanding of bat infection dynamics at multiple biological scales. We first present metrics for measuring individual bat responses to infection and challenges associated with using these metrics. We next discuss infection dynamics within bat populations of the same species, before introducing complexities that arise in multi-species communities of bats, humans and/or livestock. Finally, we outline critical gaps and opportunities for future interdisciplinary work on topics involving bats and their microbes.

Phylogeographic Aspects of Bat Lyssaviruses in Europe: A Review

During the last few decades, bat lyssaviruses have become the topic of intensive molecular and epidemiological investigations. Since ancient times, rhabdoviruses have caused fatal encephalitis in humans which has led to research into effective strategies for their eradication. Modelling of potential future cross-species virus transmissions forms a substantial component of the recent infection biology of rabies. In this article, we summarise the available data on the phylogeography of both bats and lyssaviruses in Europe and the adjacent reg ions, especially in the contact zone between the Palearctic and Ethiopian realms. Within these zones, three bat families are present with high potential for cross-species transmission and the spread of lyssaviruses in Phylogroup II to Europe (part of the western Palearctic). The lack of effective therapies for rabies viruses in Phylogroup II and the most divergent lyssaviruses generates impetus for additional phylogenetic and virological research within this geographical region.

Pregnancy reduces concurrent pup care behaviour in meerkats, generating differences between dominant and subordinate females

In some mammals, and particularly in cooperative breeding ones, successive bouts of reproduction can overlap so that a female is often pregnant while still nurturing dependent young from her previous litter. Such an overlap requires females to divide their energetic budget between two reproductive activities, and pregnancy costs would consequently be expected to reduce investment in concurrent offspring care. However, explicit evidence for such reductions is scarce, and the potential effects they may have on work division in cooperative breeders have not been explored. Using 25 years of data on reproduction and cooperative behaviour in wild Kalahari meerkats, supplemented with field experiments, we investigated whether pregnancy reduces contributions to cooperative pup care behaviours, including babysitting, provisioning and raised guarding. We also explored whether pregnancy, which is more frequent in dominants than subordinates, could account for the reduced contributions of dominants to the cooperative pup care behaviours. We found that pregnancy, particularly at late stages of gestation, reduces contributions to cooperative pup care; that these reductions are eliminated when the food available to pregnant females is experimentally supplemented; and that pregnancy effects accounted for differences between dominants and subordinates in two of the three cooperative behaviours examined (pup provisioning and raised guarding but not babysitting). By linking pregnancy costs with reductions in concurrent pup care, our findings illuminate a trade-off between investment in successive, overlapping bouts of reproduction. They also suggest that some of the differences in cooperative behaviour between dominant and subordinate females in cooperative breeding mammals can be a direct consequence of differences in their breeding frequency.

Anesthesia, pain management and surgical approach of ovariectomy or orchiectomy in six Egyptian fruit bats (Rousettus aegyptiacus): A case report

The purpose of this report is to describe the anesthetic and analgesic management and the surgical procedures of gonadectomy in six (four females and two males) healthy adult Egyptian fruit bats (Rousettus aegyptiacus). Bats were anesthetized with a combination of alfaxalone, midazolam, and morphine administered subcutaneously. Incisional line infiltration using bupivacaine was administered in all bats, and additional bilateral intratesticular injection was administered in the males. Ovariectomy was performed via a dorsal approach, by bilateral midline skin incisions at the paralumbar fossa level. Orchiectomy was performed via a ventral approach, by bilateral midline incisions of scrotal skin above the testes. Following surgery, all bats were administered flumazenil for midazolam reversal, and meloxicam for postoperative analgesia, subcutaneously. All bats recovered from anesthesia uneventfully. Bats were monitored for complications up to 10 days following surgery, when skin sutures were removed. No morbidities or mortalities occurred during this period in any of the bats. In conclusion, ventral approach orchiectomy and dorsal approach ovariectomy using the injectable combination alfaxalone-midazolam-morphine in conjunction with local anesthesia and meloxicam are feasible procedures in Egyptian fruit bats and can be performed with relative ease. However, further studies using these techniques in a larger group of bats should be performed to establish their safety.

Seasonal shedding patterns of diverse henipavirus-related paramyxoviruses in Egyptian rousette bats

Bat-borne viruses in the Henipavirus genus have been associated with zoonotic diseases of high morbidity and mortality in Asia and Australia. In Africa, the Egyptian rousette bat species (Rousettus aegyptiacus) is an important viral host in which Henipavirus-related viral sequences have previously been identified. We expanded these findings by assessing the viral dynamics in a southern African bat population. A longitudinal study of henipavirus diversity and excretion dynamics identified 18 putative viral species circulating in a local population, three with differing seasonal dynamics, and the winter and spring periods posing a higher risk of virus spillover and transmission. The annual peaks in virus excretion are most likely driven by subadults and may be linked to the waning of maternal immunity and recolonization of the roost in early spring. These results provide insightful information into the bat-host relationship that can be extrapolated to other populations across Africa and be communicated to at-risk communities as a part of evidence-based public health education and prevention measures against pathogen spillover threats.

Overview of Bat and Wildlife Coronavirus Surveillance in Africa: A Framework for Global Investigations

The ongoing coronavirus disease 2019 (COVID-19) pandemic has had devastating health and socio-economic impacts. Human activities, especially at the wildlife interphase, are at the core of forces driving the emergence of new viral agents. Global surveillance activities have identified bats as the natural hosts of diverse coronaviruses, with other domestic and wildlife animal species possibly acting as intermediate or spillover hosts. The African continent is confronted by several factors that challenge prevention and response to novel disease emergences, such as high species diversity, inadequate health systems, and drastic social and ecosystem changes. We reviewed published animal coronavirus surveillance studies conducted in Africa, specifically summarizing surveillance approaches, species numbers tested, and findings. Far more surveillance has been initiated among bat populations than other wildlife and domestic animals, with nearly 26,000 bat individuals tested. Though coronaviruses have been identified from approximately 7% of the total bats tested, surveillance among other animals identified coronaviruses in less than 1%. In addition to a large undescribed diversity, sequences related to four of the seven human coronaviruses have been reported from African bats. The review highlights research gaps and the disparity in surveillance efforts between different animal groups (particularly potential spillover hosts) and concludes with proposed strategies for improved future biosurveillance.

Wing: A suitable nonlethal tissue type for repeatable and rapid telomere length estimates in bats

Telomeres are used increasingly in ecology and evolution as biomarkers for ageing and environmental stress, and are typically measured from DNA extracted from nonlethally sampled blood. However, obtaining blood is not always possible in field conditions and only limited amounts can be taken from small mammals, such as bats, which moreover lack nucleated red blood cells and hence yield relatively low amounts of DNA. As telomere length can vary within species according to age and tissue, it is important to determine which tissues serve best as a representation of the organism as a whole. Here, we investigated whether wing tissue biopsies, a rapid and relatively noninvasive tissue collection method, could serve as a proxy for other tissues when measuring relative telomere length (rTL) in the Egyptian fruit bat (Rousettus aegyptiacus). Telomeres were measured from blood, brain, heart, kidney, liver lung, muscle and wing, and multiple wing biopsies were taken from the same individuals to determine intra-individual repeatability of rTL measured by using qPCR. Wing rTL correlated with rTL estimates from most tissues apart from blood. Blood rTL was not significantly correlated with rTL from any other tissue. Blood and muscle rTLs were significantly longer compared with other tissues, while lung displayed the shortest rTLs. Individual repeatability of rTL measures from wing tissue was high (>70%). Here we show the relationships between tissue telomere dynamics for the first time in a bat, and our results provide support for the use of wing tissue for rTL measurements.

Spatial networks differ when food supply changes: Foraging strategy of Egyptian fruit bats

Animals are faced with a range of ecological constraints that shape their behavioural decisions. Habitat features that affect resource abundance will also have an impact, especially as regards spatial distribution, which will in turn affect associations between the animals. Here we utilised a network approach, using spatial and genetic data, to describe patterns in use of space (foraging sites) by free-ranging Egyptian fruit bats (Rousettus aegyptiacus) at the Dakhla Oasis in Egypt. We observed a decrease in home range size during spring, when food availability was lowest, which was reflected by differences in space sharing networks. Our data showed that when food was abundant, space sharing networks were less connected and more related individuals shared more foraging sites. In comparison, when food was scarce the bats had few possibilities to decide where and with whom to forage. Overall, both networks had high mean degree, suggesting communal knowledge of predictable food distribution.

Anatomical features of the tongue of two chiropterans endemic in the Egyptian fauna; the Egyptian fruit bat (Rousettus aegyptiacus) and insectivorous bat (Pipistrellus kuhlii)

The current study aimed to investigate the tongue (lingual) morphometry, histology, and histochemistry of two chiropterans endemic in the Egyptian fauna, and having different feeding preferences. The tongues of nine adult individuals of each species were utilized in our investigation. The tongue of fruit-eating bat was observed relatively longer than the one of insect-eating bat. Grossly, the insect-eating bat had a lingual prominence on the dorsum of lingual body, while the fruit-eating bat had a concave midline over the lingual body. Histologically, numerous forms of lingual papillae were scattered along the dorsal epithelium of the tongue. The lingual papillae of the fruit-eating bat seem to be well adapted for piercing the skin of a fruit and liquid sap retention. The lingual glands of both species were lodged in the muscular layer. Two main sets were identified; the serous von Ebner's gland usually seen accompanied by the circumvallate papillae and Weber's gland with mixed mucoserous secretions. Von Ebner's gland showed more prominent acidic mucins, while Weber's gland expressed neutral mucins. The lingual epithelium of the fruit-eating bat had an outer covering of cornified non-nucleated epithelium. On the other hand, the insect-eating bat had an outer covering of nucleated epithelium. It is for the first time to record the existence of the entoglossal plates of both species which consisted of a bony core in the fruit-eating bat and a cartilaginous element in the insect-eating bat. The current study represents an attempt to shed more light on the tongue evolution among mammalian vertebrates.

Possible importance of carcasses for ebolavirus persistence in the ecosystem

Some outbreaks caused by ebolaviruses have been associated with wildlife mortalities in the past. Here, we discuss the possible roles played by animal carcasses during an ebolavirus outbreak. Corpses of wild animals that died due to ebolavirus infection or other reasons might be eaten by vertebrates and invertebrates, spreading live ebolaviruses to other animals, including humans. To prevent and contain an ebolavirus outbreak, not only potential reservoirs but also all organisms with a high likelihood of virus exposure need to be investigated.

Exploring the genome and transcriptome of the cave nectar bat Eonycteris spelaea with PacBio long-read sequencing

Background

In the past two decades, bats have emerged as an important model system to study host-pathogen interactions. More recently, it has been shown that bats may also serve as a new and excellent model to study aging, inflammation, and cancer, among other important biological processes. The cave nectar bat or lesser dawn bat (Eonycteris spelaea) is known to be a reservoir for several viruses and intracellular bacteria. It is widely distributed throughout the tropics and subtropics from India to Southeast Asia and pollinates several plant species, including the culturally and economically important durian in the region. Here, we report the whole-genome and transcriptome sequencing, followed by subsequent de novo assembly, of the E. spelaea genome solely using the Pacific Biosciences (PacBio) long-read sequencing platform.

Findings

The newly assembled E. spelaea genome is 1.97 Gb in length and consists of 4,470 sequences with a contig N50 of 8.0 Mb. Identified repeat elements covered 34.65% of the genome, and 20,640 unique protein-coding genes with 39,526 transcripts were annotated.

Conclusions

We demonstrated that the PacBio long-read sequencing platform alone is sufficient to generate a comprehensive de novo assembled genome and transcriptome of an important bat species. These results will provide useful insights and act as a resource to expand our understanding of bat evolution, ecology, physiology, immunology, viral infection, and transmission dynamics.

First record of the Egyptian fruit bat, Rousettus aegyptiacus (Pteropodidae), from Kastellorizo island, Greece

The Egyptian fruit bat (Rousettus aegyptiacus) is a pteropodid species with a large part of its range in the Palearctic region. It has a quite discontinuous range from sub-Saharan Africa to NW India, including SW Turkey. In this note we present the first record of the Egyptian fruit bat in Greek territory, observed during a zoological expedition on the island of Kastellorizo (Dodecanese, Greece). At least three specimens were observed foraging a white mulberry in the town of Megisti on May 4 2017, but no individual was spotted during a summer expedition in August 2017.