Bats: important reservoir hosts
of emerging viruses
Charles H. Calisher (C.S.U., Ft.
Collins), James E. Childs (Yale U.,
New Haven), Hume E. Field
(Department of Primary Industries and
Fisheries, Brisbane), Kathryn V.
Holmes (U.C.H.S.C., Aurora), Tony
Schountz (U.N.C., Greeley)
Pallid Bat
(Antrozous pallidus)
Western Pipistrelle
(Pipistrellus hesperus)
Red Bat
(Lasiurus blossevillii)
Little brown bat
(Myotis lucifugus)
Townsend’s Big-eared bat
(Corynorhinus townsendii)
Blyth's (Glossy) Horseshoe Bat
(Rhinolophus lepidus)
Of the more than 4,600 recognized
species of mammals …
1,116 (about 25%) are of bats.
Bats are grouped into two
suborders, Megachiroptera,
containing a single family, and
Microchiroptera, containing 17
families
Bats
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They are the only flying mammals
They echolocate
Some hibernate or enter torpor
Fruit-eating bats may have a wing span of up
to 2 meters
Other bats have wing spans as small as 130
mm
Some have been known to live for 35 years
As many as 300 have been known to roost
together per 0.09 meters
The people who discovered Carlsbad Caverns found the cave
entrance by following what they thought was a plume of smoke.
The smoke was actually a column of Mexican free-tail bats exiting
the cave.
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Mexican free-tail bats at Carlsbad Caverns –
8.7 million in 1936; approximately 200,000 by 1973.
Similar declines have been noted throughout the southwestern
United States and Mexico. “Development”, the pesticide DDT,
closing old mines, and other changes (stupidity is not a “change”)
are thought to be the primary causes of this decline.
Bats disperse the seeds and
pollinate the flowers of many
plants.
Fruits that depend on bats for
pollination or seed dispersal
include: bananas, peaches,
dates, carob, avocados, jack fruit,
plantains, mango, guava,
cashews, figs, and many more
Dietary characters
Fruit bats: fruits and flowers
 Vampire bats: blood (bats of only one
species are obligately
hematophagous)
 Other bats: insects (moths, ants,
termites, wasps, leafhoppers, beetles,
crickets, flies, bugs, midges,
mosquitoes, and others)
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Pest control
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One bat may eat ~ 500 mosquitoes/hour
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~ 10 hours/night = 5,000 mosquitoes
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~ 200,000 bats x 5,000 mosquitoes = 1 x
109 =
~ 1, 000, 000, 000 mosquitoes
 Per night!
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Order Chiroptera, Family
Megachiroptera
Subfamily
Pteropodidae
Genera
42
Species
186
Large Flying Fox
(Pteropus vampyrus)
Order Chiroptera, Family Microchiroptera
Subfamily
Craseonycteridae
Emballonuridae
Furipteridae
Megadermatidae
Molossidae
Mormoopidae
Mystacinidae
Myzopodidae
Natalidae
Noctilionidae
Nycteridae
Phyllostomidae
Rhinolophidae
Rhinopomatidae
Thyropteridae
Vespertilionidae
Total
Genera
1
13
2
4
16
2
1
1
3
1
1
56
1
1
1
47
Species
1
51
2
5
100
10
2
1
8
2
16
160
77
4
3
407
151
849
Total number of viruses isolated
from bats of various species =
77
Recently emerged bat-borne viruses
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Hendra virus:
September 1994 – QLD horse trainer, his
stablehand, and most of his horses
became ill in Hendra, a suburb of
Brisbane. The trainer and 14 horses died.
Samples sent to AAHL, Geelong
New virus isolated; named Hendra virus
Epidemiologic investigations
Hendra virus not detected in rodents,
cats, dogs, goats, sheep, birds, or other
vertebrates, or in mosquitoes
Antibody to Hendra virus detected in fruit
bats
Hendra virus isolated from fruit bats
October 1995 – Farmer from Mackay died of
Hendra virus. He had had close contact with two
horses in August 1994 during their clinical illnesses
and when they were autopsied. Subsequent tests
at Geelong on tissue from the dead horses
revealed Hendra virus.
January 1999 – a horse from a property near
Cairns died from Hendra disease.
December 2004 – Hendra virus confirmed in a
dead horse from the Townsville area.
Menangle and Tioman viruses
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Mild illness in people at a piggery in New South
Wales
Menangle virus isolated from bats roosting near
the piggery
Tioman virus isolated from fruit bats (no disease
recognized in humans)
Nipah virus
1999 – Outbreak of encephalitis and respiratory
illness in Malaysia
Diagnosis: “A particularly virulent form of
Japanese encephalitis” (a disease caused by an
arbovirus)
40% case-fatality rate
Ridiculous diagnosis!
Epidemiology
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Patients were all adult, male, Chinese, pig
farmers (does that sound to you like a mosquitoborne virus?)
Most people in Malaysia are vaccinated against
or infected with Japanese encephalitis virus
(JEV) when they are young
Pigs also were dying (JEV is not pathogenic for
pigs)
Patients did not have IgM antibody to JEV
Nipah virus isolated from fruit bats
September 2005
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Lau SK, Woo PC, Li KS, Huang Y,
Tsoi, HW, Wong BH, Wong SS,
Leung SY, Chan KH and Yuen KY
(2005) Severe acute respiratory
syndrome coronavirus-like virus in
Chinese horseshoe bats. Proc. Natl.
Acad. Sci. (USA). 102:14040-14045.
Viruses isolated from or viral RNA detected in
bats
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Family Rhabdoviridae
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genus Lyssavirus
Rabies virus
Lagos bat virus
Duvenhage virus
Australian bat lyssavirus
European bat lyssavirus 1
European bat lyssavirus 2
Aravan virus
Khujand virus
Irkut virus
West Caucasian bat virus
Number of bat species
numerous, world-wide
3
3
3
2
6
1
1
1
1
Viruses isolated from or viral RNA detected in bats
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Family Rhabdoviridae
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genus unassigned
Gossas virus
Kern Canyon virus
Mount Elgon bat virus
Oita 296 virus
Number of bat species
1
1
1
1
Family Orthomyxoviridae, genus Influenzavirus A
Influenza A virus
1
Family Paramyxoviridae, genus Henipavirus
Hendra virus
4
Nipah virus
3
Viruses isolated from or viral RNA detected in bats
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Family Paramyxoviridae
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genus Rubulavirus
Menangle virus
Tioman virus
Mapuera virus
Number of bat species
1
1
1
Family Paramyxoviridae, genus undetermined
a parainfluenzavirus
1
Family Coronaviridae
(Group 1) coronaviruses (= 2)
(Group 2) SARS coronavirus
2
4
Family Togaviridae, genus Alphavirus
Chikungunya virus
1
Sindbis virus
2
Venezuelan eq. enc. virus
3
Viruses isolated from or viral RNA detected in bats
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Family Flaviviridae
 genus Flavivirus
Bukalasa bat virus
Carey Island virus
Central European encephalitis virus
Dakar bat virus
Entebbe bat virus
Japanese encephalitis virus
Jugra virus
Kyasanur Forest disease virus
Montana Myotis leucoencephalitis virus
Phnom-Penh bat virus
Rio Bravo virus
St. Louis encephalitis virus
Saboya virus
Sokuluk virus
Tamana bat virus
Uganda S
West Nile virus
Yokose virus
Number of bat species
1
2
1
3
2
3
1
2
1
2
2
1
1
1
1
1
1
1
Viruses isolated from or viral RNA detected in bats
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Family Bunyaviridae
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genus Bunyavirus
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Catu virus
Guama virus
Nepuyo virus
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Family Bunyaviridae
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Hantaan virus
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Family Bunyaviridae
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Family Bunyaviridae
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2
genus Phlebovirus
Rift Valley fever virus
Toscana virus
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1
1
2
genus Hantavirus
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Number of bat species
2
1
genus unassigned
Kaeng Khoi virus
Bangui virus
1
3
Viruses isolated from or viral RNA detected in bats
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Family Reoviridae
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genus Orbivirus
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Ife virus
Japanaut virus
Fomede virus
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Family Reoviridae
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Number of bat species
1
1
1
genus Orthoreovirus
Nelson Bay virus
Pulau virus
Broome virus
1
1
1
Family Arenaviridae
Tacaribe virus
2
Viruses isolated from or viral RNA detected in bats
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Family Herpesviridae
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genus unassigned
Number of bat species
Agua Preta virus
a cytomegalovirus
Parixa virus
1
1
1
subfamily Gammaherpesvirinae
gammaherpesvirus 1
gammaherpesvirus 2
gammaherpesvirus 3
gammaherpesvirus 4
gammaherpesvirus 5
gammaherpesvirus 6
gammaherpesvirus 7
4
2
3
2
1
1
1
subfamily Betaherpesvirinae
betaherpesvirus 1
2
Viruses isolated from or viral RNA detected in bats
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Family Picornaviridae
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genus undetermined
Number of bat species
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Juruaca virus
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Unclassified
Issyk-kul = Keterah virus 14
Mojui dos Campos virus
1
Yogue virus
1
Kasokero virus
1
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1
Virus isolated from a bat
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Family Papillomaviridae
genus new, unnamed
isolated from an Egyptian fruit bat
Viral RNA detected in bats
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Family Filoviridae
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Genus Marburgvirus
Lake Victoria marburgvirus
Number of bat species
3
Genus Ebolavirus
Zaire ebolavirus
3
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Chiropteran species from which viruses have been
isolated or in which viral RNA has been detected
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Of 1,116 recognized species of bats –
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Viruses have been isolated from bats of
33 viruses have been isolated from bats of
12 viruses have been isolated from bats of
4 viruses have been isolated from bats of
5 viruses have been isolated from bats of
3 viruses have been isolated from bats of
1 virus has been isolated from bats of
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No viruses have been detected in bats of 1,036 species
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80
1
2
5
4
5-6
14
Why have there been so few
studies of viruses in bats?
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Bats of many species are “endangered” or
“threatened” (or extinct).
Bats of some species are protected and it is
illegal to capture them.
It is difficult to capture bats.
Few investigators who are knowledgeable about
bats also are knowledgeable about viruses, and
vice versa.
Until recently, bats were not considered when
epizoological studies of viruses were planned.
Why are these viruses emerging now?
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1. *** We had not looked. ***
2. We are impinging on natural areas.
3. We are monumentally and irreversibly
altering formerly natural areas.
4. We are dependent on oil and other
extractive industries (These make a
mess).
5. We need more and more food for more
and more people.
There is more work to
be done!