In brief– Research news and discovery

ONE more reason not to eat our

close living relatives. Of the three

strains of HIV known to infect

humans, we know that two – the

one causing the global AIDS

epidemic and another that has

infected a small number of people

in Cameroon – came from a

chimpanzee virus called SIV. The

source of the third strain, which

infects people in western central

Africa, was a mystery. Now we

The next mystery is how the

gorillas got it. The gorilla virus

is descended from the chimp

variety, but gorillas are vegetarian

and rarely encounter chimps.

There is little mystery about

how humans contracted the virus,

though: local people picked it

up hunting gorillas for food and

traditional medicine. That means

the virus could yet cross again

and create another HIV strain, say

the researchers, especially as

growing demand for “bushmeat”

leads to more hunting.

know it came from gorillas.

Martine Peeters and colleagues

at the University of Montpelier in

France have discovered the virus

in the droppings of gorillas living

in remote forests in Cameroon

(Nature, vol 444, p 164). The

infected gorillas lived up to

400 kilometres apart, so the

researchers think it must be a

normal or endemic virus in the

animals, as SIV is in chimps.

WHEN you are ill, having a fever is

not necessarily a bad thing. Now

we know a little more about why:

an elevated body temperature

helps the immune system

identify the cause of an infection

and then eradicate it, say Sharon

Evans and colleagues at the

Roswell Park Cancer Institute in

Buffalo, New York.

The team replicated the effects

of a fever in mice by keeping them

at 39.5 °C. This doubled the

number of lymphocytes passing

through the lymph nodes, which is

where the immune system checks

which lymphocytes recognise any

infective agents. Those that do

are rapidly multiplied and sent

out in the bloodstream to combat

the pathogen.

An elevated body temperature

somehow activates cells in the

lymph nodes that in turn solicit

more lymphocytes to pass

through, says Evans. This should

help the body react faster to

infection (Nature Immunology,

DOI: 10.1038/ni1406).

Give me fever

String up the dingoes, and other species pay the priceTHE eastern hare-wallaby is gone. The lesser bilby is no

more. In the past two centuries, these and 16 other

mammals have become extinct in Australia – almost half

the mammalian species lost worldwide over that time.

Changes in how people use fire to clear land, the

introduction of rabbits and disease, and sheep farming

have in the past been blamed for the extinctions. Now a

team led by Chris Johnson of James Cook University in

Townsville, Queensland, says the cause is far simpler: the

persecution of mainland Australia’s only top predator, the

dingo. “Where there are no dingoes, introduced predators

are rife, and up to 65 per cent of ground-dwelling mammal

species have disappeared,” Johnson says. “If dingoes

hadn’t been so savagely persecuted, we wouldn’t have had

this total catastrophe.”

By mapping habitat type and the range of ground-

dwelling marsupials, rabbits, foxes, dingoes and sheep,

Johnson’s team has shown that wherever dingo populations

have slumped, prey species such as the lesser bilby have

become extinct (Proceedings of the Royal Society B, DOI:

10.1098/rspb.2006.3711). That adds to circumstantial and

historical evidence that dingoes protect small marsupials

by reducing numbers of introduced predators, such as the

fox, whose numbers explode in the dingo’s absence.

KEN

GRIF

FITH

S/NH

PA

www.newscientist.com 11 November 2006 | NewScientist | 17

YET more evidence is in that the

Ebola virus is spreading in a wave

across Africa – putting the world’s

last big populations of lowland

gorillas directly in its path.

In 2003, an outbreak of Ebola

struck gorillas living in the Congo.

Bats in the area at that time were

also carrying the virus, researchers

recently discovered (New Scientist,

3 December 2005, p 20). That

meant either the virus had always

been lurking in bats, and spread to

the gorillas, or that the bats were

newly infected as the epidemic

crossed their territory.

Now researchers have found

that the bat viruses all descended

recently from a common ancestor,

confirming that the virus was new

to the bats and is on the march

(PLoS Pathogens, vol 2, e90).

Ebola heads for last great apes

Gorillas missing link in HIV mystery

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