Bats and the origin of outbreaks - Reuters UK

As the World Health Organization reaches its findings on the zoonotic origins of the novel coronavirus, we explain why bats make such ideal hosts for disease-causing viruses.

As the World Health Organization reaches its findings on the zoonotic origins of the novel coronavirus, we explain why bats make such ideal hosts for disease-causing viruses.

As the World Health Organization reaches its findings on the zoonotic origins of the novel coronavirus, we explain why bats make such ideal hosts for disease-causing viruses.

As the World Health Organization reaches its findings on the zoonotic origins of the novel coronavirus, we explain why bats make such ideal hosts for disease-causing viruses.

As the World Health Organization reaches its findings on the zoonotic origins of the novel coronavirus, we explain why bats make such ideal hosts for disease-causing viruses.

As the World Health Organization reaches its findings on the zoonotic origins of the novel coronavirus, we explain why bats make such ideal hosts for disease-causing viruses.

Changes in the environment are driving displaced species of animals into new habitats, allowing them to mix with other species or potential hosts.

Those shifts, combined with greater human interaction with animals as people move deeper into forests, increases the chances of a virulent virus jumping species.

This kind of spillover, when a pathogen in one species could start circulating in another and potentially create a new disease – is what appears to have happened in China with the virus that causes COVID-19.

Among the largest species of bat with a wingspan of up to 1.5 m.

Among the largest species of bat with a wingspan of up to 1.5 m.

Among the largest species of bat with a wingspan of up to 1.5 m.

The Malayan fruit bat is among the largest species of bat.

The Malayan fruit bat is among the largest species of bat.

The reservoir host species often displays no symptoms despite carrying the pathogen, as the hosts and germs are often well-adapted to each other

THE UNIVERSE OF BATS

Leaf-nosed bats

leaf-nosed bats

Ghost-faced bats

short-tailed bats

Free-tailed bats

Simple-nosed bats

THE UNIVERSE OF BATS

Leaf-nosed bats

Bulldog bats

short-tailed bats

Free-tailed bats

Simple-nosed bats

Ghost-faced bats

False vampire bats

Sac-winged bats

Old world fruit bats

THE UNIVERSE OF BATS

Leaf-nosed bats

short-tailed bats

Free-tailed bats

leaf-nosed bats

Ghost-faced bats

Simple-nosed bats

False vampire bats

Old world fruit bats

Sac-winged bats

THE UNIVERSE OF BATS

Leaf-nosed bats

leaf-nosed bats

Ghost-faced bats

short-tailed bats

Free-tailed bats

Simple-nosed bats

THE UNIVERSE OF BATS

Leaf-nosed bats

short-tailed bats

Free-tailed bats

leaf-nosed bats

Ghost-faced bats

Simple-nosed bats

False vampire bats

Old world fruit bats

Horseshoe bats

Bent-winged bats

Slit-faced bats

Many deadly viruses in the past have originated from bats including the deadly Ebola outbreaks in Western Africa

Nipah, also carried by bats, has already caused human outbreaks across South and South East Asia and has “serious epidemic potential”, according to global health and infectious disease specialists

Scientists have discovered that SARS and MERS were caused by viruses that originated in bats, with other animals serving as intermediate hosts

Bats are a group of flying mammals, with more than 1,300 species in 20 families, according to IUCN

They make up approximately 20% of all mammal species and are found all over the world except for the Arctic, the Antarctic and a few oceanic islands

There are approximately 2,300 species of rodents in 33 families, making up about 40% of all mammals

Rodents are believed to harbour more viruses as a group but bats harbour more viruses per species

The diversity of both groups has been seen by scientists as a possible mechanism for driving virus diversity, as the greater number of species can create more potential niches for viruses

Some bats roost in forests while others in caves

Most bats eat insects such as beetles, moths and mosquitoes

Some bats eat fruit, nectar, seeds and pollen from flowers while others eat small animals such as birds, fish, frogs and lizards

A small number of bats consume blood

The smallest bats are the Kitti’s hog-nosed bat at about 3cm (1.2 inches) and the biggest, known as a flying fox, can grow to around 45cm (18 inches)

Studies have shown that bats are unique when it comes to hosting zoonotic viruses even when compared to rodents, as bats host more zoonotic viruses per species than rodents do

Apart from diversity, other traits that make bats suitable as virus hosts include their size and longevity

When bat species with large ranges migrate or use seasonal roosting sites for hibernation, this increases potential exposure to pathogens

Moreover, members of some bat species live together in large communities with close-quarter colonies in locations such as caves

There is a high energy and metabolic demand for flight, leading to elevated body temperatures in bats which is similar to the effects of human fever that occurs during immune response

Some bats play important roles such as plant pollination and seed dispersal

Bats can pollinate more than 500 species of plants including avocados, bananas, dates and mangoes

In this sense, bats are important economically for people

Some bats can also play critical roles in spreading seeds and regrowing forests

The insect-eating bats also serve as natural biological controls of insects, consuming millions of them at night, including some major crop pests

More than 200 bat species (~15%) in 60 countries are considered threatened with extinction and more than 20 are critically endangered

In addition, eight bat species have been documented as having gone extinct in the recent past

Almost 30% of all bat species face some level of threat

Bat species

Almost 30% of all bat species face some level of threat

Bat species

Nearly 30% of the assessed species with sufficient data are threatened, near threatened with extinction or extinct

Bat species

Bat species

Nearly 30% of the assessed species with sufficient data are threatened, near threatened with extinction or extinct

Nearly 30% of the assessed species with sufficient data are threatened, near threatened with extinction or extinct

Bat species

There are nearly 250 bat species classified as Data Deficient (~19%), a relatively high proportion when compared to other mammals in general (~13%) or birds (~1%), showing that for many bat species not enough is known to even assess their status

Bats are also exploited for food or traditional medicine, as around 170 of bat species have been recorded to be hunted

Given their larger size, Old World fruit bats are disproportionately affected by hunting, with roughly half of the species in that family hunted