2006/11/09
From: Mathaba
Animals are
increasing becoming the cause of many human deaths; a new study shows an
estimated 50 million people worldwide contracted animal born diseases
between 2000 and 2005.
(Xinhua) -- Could it be animals around the world are
starting to fight back? A new study shows an estimated 50 million people
worldwide contracted diseases -- and 78,000 died -- from dogs, chickens,
cattle and mosquitoes between 2000 and 2005.
The finding reveals the global urgency for doctors to stay aware of zoonotic
illnesses that are transmitted by non-human animals.
"This comes on the heels of other major zoonotic viral epidemics in the last
decade," said virologist Jonathan Heeney of the Biomedical Primate Research
Center in The Netherlands.
By reviewing past studies, Heeney found the diseases responsible for the
majority of zoonotic illnesses seem to be increasing. These include severe
acute respiratory syndrome (SARS), West-Nile virus, Ebola virus and
monkeypox.
Zoonotic killers during 2000 to 2005 included rabies (estimated 30,000
killed), dengue virus (affected 50 million people, killed around 25,000),
Japanese encephalitis virus (estimated 15,000 died), Lassa fever (affected
up to 300,000, killed about 5,000) and SARS Corona virus (774 died).
Rabies is spread by host animals such as dogs, cats, bats and horses. Dengue
virus and Japanese encephalitis is spread by mosquitoes. Lassa fever is
spread by a rodent known as the multimammate rat, and the host for SARS is
yet to be discovered.
There are no effective vaccines for some of the most common zoonotic
viruses. Heeney said doctors and veterinarians need to work together to
tackle this increasing global threat.
"They are in the best position to identify trends and patterns, such as
increases in the number of deaths of wild or domestic animals," Heeney said.
"Awareness and surveillance of ecosystems will play a key role in
identifying and controlling new, emerging and re-emerging viral zoonotics."
The bird flu, or H5N1, is the current No. 1 attention getter because of its
potential to spread from chickens and other birds to humans, and because the
virus may mutate in a way that allows it to spread between humans. During
the study period, bird flu killed just over half of the 145 people infected
with the virus.
An estimated 700,000 to 2.7 million people -- 75 percent of them African
children -- die of malaria each year. However, malaria is not a zoonotic
disease, because the virus depends on a human host for part of its life
cycle.
Over time, viruses can develop the needed "machinery" for efficient
transmission not only from the animal host to humans, but from human to
human. When this happens, Heeney said, zoonotic illnesses can become serious
human killers with potential to reach epidemic proportions.
While vaccines have eradicated devastating human diseases, such as smallpox,
other related viruses, such as monkeypox, could hit people whose smallpox
vaccines have expired.
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