- ATLANTA, March 24 " Stronger ties between veterinarians and physicians
are needed to prevent further outbreaks of the animal diseases that have
caused deaths and serious illness among humans in many countries in recent
years, international health officials said at a meeting here.
- The diseases are known as zoonoses because
they affect animals primarily, and humans only incidentally. The AIDS,
SARS and A(H5N1) avian influenza viruses and at least eight other infectious
agents carried by animals have led to new and emerging human diseases in
- The spread of new and emerging diseases
can be a two-way street as people occasionally transmit human diseases
like tuberculosis to elephants in captivity in the United States and Sweden
and mongooses in Africa.
- The latest and most visible zoonosis
is A(H5N1) avian influenza. Through illness and culling, the virus has
led to the death of an estimated 200 million birds worldwide. In Asia and
Europe, the virus has caused 185 human cases of which 104 have been fatal.
- New diseases are occurring in part because
of globalization and because people are encroaching on areas once reserved
for wildlife. After the AIDS virus infected tens of millions of people
worldwide and an animal disease, anthrax, was deliberately spread through
the United States postal system after Sept. 11, public health has become
intertwined with national security.
- Experts at the three-day International
Symposium on Emerging Zoonoses said they had no way of predicting what
human disease would emerge next from an animal source.
- Preventing further outbreaks, participants
said, will require a variety of measures, including more education about
zoonoses among veterinarians and physicians; more integration of animal
diseases into health plans; the creation of more laboratories to detect
animal diseases; and possibly changes in the foods people eat and the animals
they keep as pets.
- Breaking down barriers among government
agencies, academia and special interest groups will be needed as scientists
seek new ways to collect reliable evidence to protect the health of animals
and humans, participants said.
- But "no single institution has the
capacity to do all this," said Dr. Pierre Formenty, a veterinarian
and epidemiologist at the World Health Organization in Geneva.
- The meeting was the first between the
World Animal Health Organization, a cooperative of chief veterinary officers
from 167 countries, based in Paris, and the federal Centers for Disease
Control and Prevention, based in Atlanta, said Dr. Lonnie King, the dean
of Michigan State University's veterinary school.
- Dr. King is soon joining the C.D.C.,
which is expected to become a laboratory and epidemiology reference center
for the animal organization.
- "We are creating the conditions
for the spread of these viruses" that cause zoonoses and human illness
through tourism, hunting and farming, said Dr. Bruno Chomel, a professor
of zoonoses at the University of California, Davis.
- For example, Dr. Chomel said, the corn
mouse that carries the virus that causes Argentine hemorrhagic fever has
spread its range with changes in farming, leading to outbreaks of the bleeding
- The liver infection caused by the hepatitis
E virus, which has been detected mainly in poor countries, is being increasingly
recognized in wealthy countries in small numbers. Two outbreaks of hepatitis
E occurred recently in Japan after people ate raw liver from infected wild
boar and deer, Dr. Chomel said.
- In 1999, scientists discovered the Nipah
virus among pig workers in Malaysia and Singapore who developed inflammation
of the brain and respiratory illness. Farming practices on pig farms where
fruit trees were abundant created opportunities for transmission of the
Nipah virus, said Dr. Peter W. Daniels of the Australian Animal Health
Laboratory in Geelong.
- Fruit bats carried the Nipah virus, and
it was transmitted to pigs that lived in an open farm environment. In turn,
the virus was transmitted to humans and their pets.
- Additional factors favoring Nipah virus
transmission were disrespect for regulations and the frequent breaking
of rules to increase profits. It was a lesson that self-regulation must
be realistically audited, Dr. Daniels said.
- The demand for exotic pets can also spread
- Customs inspectors recently stopped the
potential spread of A(H5N1) virus in Belgium by catching a man trying to
smuggle infected Thai eagles that had been stuffed alive in a roller tube.
- Cats, leopards and tigers have died from
A(H5N1) avian influenza in southeast Asia and Europe. Though the number
of cases is small, they have raised concern that the virus could become
a bigger problem among felines. The 10,000 tigers now being kept as pets
in the United States outnumber the 6,000 in the wild worldwide, Dr. Chomel
- Another zoonosis, rabies, killed 50,000
people in 2005, mainly from dog bites in Africa and Asia despite availability
of an effective vaccine, according to the World Health Organization.
- In poor countries, many dogs go unvaccinated
because they are believed to be strays. But many strays turn out not to
be strays, said Dr. Jakob Zinsstag of the Swiss Tropical Institute in Basel.
In a pilot study in Chad, his team vaccinated and tagged stray dogs. When
the Swiss team recaptured stray dogs, it found that 70 percent had been
vaccinated, concluding that their owners had let them roam freely and that
opportunities existed to conduct rabies vaccination programs.
- Many disease outbreaks like avian influenza
often lead to mass cullings that create practical and emotional problems
for animal health workers, said Dr. Larry Granger, a veterinarian at the
United States Department of Agriculture in Riverdale, Md. When mass euthanasia
of animals is carried out, all workers should be debriefed to help relieve
their stress, Dr. Granger said.
- Patricia A. Doyle, DVM, PhD- Bus Admin,
Tropical Agricultural Economics Univ of West Indies
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