* Study maps hotspots of animal-human diseases
* Emerging disease hotspots in United States and Europe
* Animal-borne diseases often hit world's poorest hardest
By Kate Kelland
LONDON, July 5 A global study mapping human
diseases that come from animals like tuberculosis, AIDS, bird
flu or Rift Valley fever has found that just 13 such diseases
are responsible for 2.4 billion cases of human illness and 2.2
million deaths a year.
The vast majority of infections and deaths from so-called
zoonotic diseases are in poor or middle-income countries, but
"hotspots" are also cropping up in the United States and Europe
where diseases are newly infecting humans, becoming particularly
virulent, or are developing drug resistance.
And exploding global demand for livestock products means the
problem is likely to get worse, researchers said.
"From cyst-causing tapeworms to avian flu, zoonoses present
a major threat to human and animal health," said Delia Grace, a
veterinary epidemiologist and food safety expert with the
International Livestock Research Institute (ILRI) in Kenya and
lead author of the study.
She said targeting these diseases in the hardest hit
countries is crucial to protecting global health, and failing to
tackle them would allow demand for meat products to "fuel the
spread of a wide range of human-animal infectious diseases."
The study, conducted by the ILRI, the Institute of Zoology
in Britain and the Hanoi School of Public Health in Vietnam,
mapped livestock-keeping and diseases humans get from animals,
and drew up a list of the top 20 geographical hotspots.
It found that Ethiopia, Nigeria, and Tanzania, as well as
India have the highest zoonotic disease burdens, with widespread
illness and death.
It also found the United States and Europe - especially
Britain - Brazil and parts of Southeast Asia may be becoming
hotspots of "emerging zoonoses", which are infecting humans for
the first time, are especially virulent or are becoming drug
The report studied so-called endemic zoonoses which cause
the vast majority of illness and death in poor countries.
One such disease is brucellosis, also known as Bang's
diseases or Mediterranean fever, which is a highly contagious
zoonosis people catch by consuming unsterilised milk or meat
from infected animals.
The researchers estimated that about one in eight livestock
in poor countries are affected by brucellosis. As well as
threatening people with disease, this also reduces milk and meat
production in cattle by around 8 percent.
The study also looked at epidemic zoonoses, which typically
occur as outbreaks - such as anthrax and Rift Valley fever - and
at the relatively rarer emerging zoonoses like bird flu. A few
of these, like HIV/AIDS and H1N1 swine flu, have shown the
ability to spread to cause pandemics.
While zoonoses can be transmitted to people by either wild
or domesticated animals, most human infections are acquired from
the world's 24 billion livestock, including pigs, poultry,
cattle, goats, sheep and camels.
The study initially looked at 56 zoonoses that together are
responsible for around 2.5 billion cases of human illness and
2.7 million human deaths per year.
It then zoomed in on the 13 most important, and found high
levels of infection with these in livestock in poor countries.
Some 27 percent of livestock in developing countries showed
signs of current or past infection with bacterial food-borne
disease - a source of food contamination and widespread illness.
The researchers estimated at least a third of the world's
cases of diarrhoeal disease are caused by animal-human diseases
and said this was the biggest zoonotic threat to public health.
John McDermott, director of the CGIAR research program on
agriculture for nutrition and health led by the International
Food Policy Research Institute (IFPRI), said that in booming
livestock sectors in developing nations the fastest growing
areas are poultry and pigs - putting the potential disease risk
emphasis on flu.
"Historically, high-density pig and poultry populations have
been important in maintaining and mixing influenza populations,"
he said in a statement accompanying the study.
"A major concern is that as new livestock systems intensify,
particularly small- and medium-sized pig production ... more
intensive systems will allow the maintenance and transmission of
pathogens. A number of new zoonoses ... have emerged in that
(Editing by Mark Potter)