Sky News Australia — Deadly bat lyssavirus detected in NT

Northern Territory residents and visitors are being warned not to handle bats after a flying fox tested positive to the deadly Australian bat lyssavirus.

This is the second bat to test positive in a matter of months and only the third case for the Northern Territory since the first was detected in 1997.

Found Australia-wide, the virus is very similar to rabies, and symptoms include severe headaches and convulsions, before it paralyses breathing and causes a fatal brain inflammation.

All three people who have contracted the virus, in Queensland, have died.

The infected flying fox was under the care of a bat carer when it became sick and died, said Malcolm Anderson, the NT’s chief veterinary officer.

‘The disease, like rabies, can have a very long incubation period, so it can be in an animal for a long time before they show signs … six months or 12 months,’ he said.

. . .

Click HERE for the complete article.

Comparative Analysis of Bat Genomes Provides Insight into the Evolution of Flight and Immunity


Guojie Zhang,1,2*† Christopher Cowled,3Zhengli Shi,4 Zhiyong Huang,1 Kimberly A. Bishop-Lilly, Xiaodong Fang,1 James W. Wynne,3 Zhiqiang Xiong,1 Michelle L. Baker,3 Wei Zhao,1 Mary Tachedjian,3 Yabing Zhu,1 Peng Zhou,3,4 Xuanting Jiang,1 Justin Ng,3 Lan Yang,1 Lijun Wu,4 Jin Xiao,1 Yue Feng,1 Yuanxin Chen,1 Xiaoqing Sun,1 Yong Zhang,1 Glenn A. Marsh,3 Gary Crameri,3 Christopher C. Broder,6 Kenneth G. Frey,5
Lin-Fa Wang,3,7† Jun Wang1,8,9

Bats are the only mammals capable of sustained flight and are notorious reservoir hosts for some of the world’s most highly pathogenic viruses, including Nipah, Hendra, Ebola, and severe acute respiratory syndrome (SARS). To identify genetic changes associated with the development of bat-specific traits, we performed whole-genome sequencing and comparative analyses of two distantly related species, fruit bat Pteropus alecto and insectivorous bat Myotis davidii. We discovered an unexpected concentration of positively selected genes in the DNA damage checkpoint and nuclear factor kB pathways that may be related to the origin of flight, as well as expansion and contraction of important gene families. Comparison of bat genomes with other mammalian species has provided new insights into bat biology and evolution.

. . .

The most conspicuous feature of bats, distinguishing them from all other mammalian species, is the capacity for sustained flight. Positive selection in the oxidative phosphorylation (OXPHOS) pathway suggests that increased metabolic capacity played a key role in its evolution (3), yet the by-products of oxidative metabolism [such as reactive oxygen species (ROS)] can produce harmful side effects including DNA damage (4). We hypothesize that genetic changes during the evolution of flight in bats likely included adaptations to limit collateral damage caused by by-products of elevated metabolic rate. Another phenomenon that has sparked intense interest in recent years is the discovery that bats maintain and disseminate numerous deadly viruses (5). In this context, we further hypothesize that the long-term coexistence of bats and viruses must have imposed strong selective pressures on the bat genome, and the genes most likely to reflect this are those directly related to the first line of antiviral defense—the innate immune system.

. . .

In summary, comparative analysis of P. alecto and M. davidii genomes has provided insight into the phylogenetic placement of bats and has revealed evidence of genetic changes that may have contributed to their evolution. Gene duplication events played a particularly prominent role in the evolution of Myotis bats and may have helped contribute to their speciation. Concentration of positively selected genes in the DNA damage checkpoint pathway in bats may indicate an important step in the evolution of flight, whereas evidence of change in components shared by the DNA damage pathway and the innate immune system raises the interesting possibility that flight-induced adaptations have had inadvertent effects on bat immune function and possibly also life expectancy (24). The data generated by this study will help to address major gaps in our understanding of bat biology and to provide new directions for future research.

Click HERE for the complete article.
Comparative Analysis of Bat Genomes Provides Insight into the Evolution of Flight and Immunity

How often do bats live over ten years?

A Japanese study found that
“Females less than two years of age constituted the majority of the members in the relatively large-sized A and B colonies investigated by the banding-recapture method, whereas older females, and males more than one year of age decreased rapidly.”

For the complete study, please see:
Age Composition of Summer Colonies in the Japanese House-dwelling Bat, Pipistrellus abramus
Kimitake Funakoshif’ and Teru Aki Uchida

Amplification of viruses in maternal colonies?

The paper here
Amplification of Emerging Viruses in a Bat Colony

describes a first wave of infection. Since the bats were probably all born in similar colonies, wouldn’t they very likely already have been previously infected? That would mean that the female bats arrived at the colony with a persistent infection.

Female bats of species normally go into a daytime torpor will maintain high daytime temperatures during reproduction. Could a rise in body temperature be the cause of the virus spike?

With a captive colony, if the droppings could be regularly checked for viruses, what’s known about persistence of viruses in bats will
become a lot less nebulous. And perhaps with infrared thermometers,
the resting temperatures might be taken without disturbing the bats.
It will be interesting to see if there’s any correlation between the
bat’s resting body temperature and the presence of viruses.

Experiment DID NOT show that bats are asymptomatic carriers of rabies

Bats, emerging infectious diseases, and the rabies paradigm revisited

It is stated that:
“More recently, the asymptomatic excretion of RABV in the saliva of
experimentally infected vampire bats, which survived the challenge
during at least 2 years of observation, was documented again (18).”

But the cited research — despite what one might expect from the title
Salivary excretion of Rabies virus by healthy vampire bats

states that
“Rabies virus was not detected in the saliva of any of the 11 animals
that succumbed (somewhat early) to rabies challenge, nor in the
control bats. In contrast, virus was detected early, and only once
(days 6, 6 and 21) in each of the three animals that survived rabies
challenge and remained healthy for at least 2 years after challenge.
At that time even vigorous dexamethasone and cyclosporine
administration failed to provoke further viral excretion.”

This seems to show that bats once recovered are no longer carriers and not that apparently healthy ones are.