The threat of zoonoses from live animal markets<\/p>\n
Karmele Llano Sanchez
\nJakarta<\/p>\n
An article published last July in Emerging Infectious Diseases
\nreports on the significant impact that the wildlife trade and
\nlive animal markets are having on human health worldwide, in
\nparticular Asia.<\/p>\n
The large population on this continent arguably increases the
\nlikelihood of a pandemic occurring. It is in this continent also
\nwhere the population is at higher risk of contracting animal-
\nborne diseases due to the encroachment of humans into wildlife
\nhabitats, and the presence of animal markets where animal
\nproducts and live animals are on sale.<\/p>\n
Presently, an outbreak of H5N1 type A influenza virus (bird
\nflu) has alerted human health authorities in Indonesia. This
\nzoonosis (an animal disease capable of being transmitted to
\nhumans) has already cost the lives of dozens of people. However,
\nthe most threatening aspect is the possibility that many other
\nzoonotic pathogens could be covertly infecting people basically
\nbecause they are difficult to diagnose by physicians.<\/p>\n
This highlights the question of where these emerging pathogens
\nare hidden and what causes them to emerge. According to Lonnie
\nKing et al, three-quarters of emerging human diseases over the
\npast two to three decades have been animal-borne, and the future
\nwill probably bring many more such outbreaks.<\/p>\n
In addition, the threat of these diseases spreading quickly
\nworldwide is reasonably high due to contemporary global transport
\npatterns: planes, ships, people and animals carry infections in
\nevery direction.<\/p>\n
Animal health has broad implications, ranging from the health
\nof individual animals, human health and global security. Animal
\ndiseases have implications not only for the global food supply
\nbut also for human health directly due to the existence of animal
\nborne diseases transmissible to humans (zoonoses).<\/p>\n
The pool of infectious pathogens shared between animals in a
\nmarket will not stay confined to these locations. To the
\ncontrary, these animals and their pathogens will be transported
\nto other areas, locally and nationally, and even internationally
\nwhen animals are smuggled outside of the country.<\/p>\n
This not only threatens people but also wildlife, when, for
\ninstance, they are eventually released by the owners because they
\nare no longer wanted, or when they escape and become a threat to
\nlocal wildlife.<\/p>\n
The likelihood of disease transmission is also increased when
\nanimals are submitted to unnatural conditions causing high stress
\nlevels.<\/p>\n
Wild animals suffer much stress when they are captured and
\ntransported, then forced into a completely unknown environment,
\nsurrounded by their most dangerous predator: humans. They are
\nalso offered for sale in cramped cages with no space to even
\nstretch their bodies.<\/p>\n
At the same time, this stress renders their immune system
\nless effective, making them more prone to infections for which
\nthey are not a natural host.<\/p>\n
Pathogens for which humans become new hosts are more hazardous
\nwhile human immunity does not yet posses the ability to fight
\nthem.<\/p>\n
Some estimations of the numbers of wild animals traded
\nannually worldwide includes approximately 40,000 live primates, 4
\nmillion live birds, 640,000 live reptiles, and 350 million live
\ntropical fish. According to one report, in a single market in
\nNorth Sulawesi up to 90,000 mammals are sold per year.<\/p>\n
Over the last 25 years, more than 35 diseases have emerged. In
\na list of 1,415 human pathogens, 61 percent are known to be
\nzoonotic, and multiple-host pathogens are twice as likely to be
\nassociated with emerging infectious diseases in humans. As much
\nas 77 percent of pathogens found in livestock are shared with
\nother host species.<\/p>\n
The rash of emerging or reemerging livestock disease outbreaks
\naround the world since the mid 1990s, including bovine spongiform
\nencephalopathy, foot-and-mouth disease, avian influenza, swine
\nfever, and other diseases, has cost the world economy $80
\nbillion.<\/p>\n
Efforts to control the spread of avian influenza in Asian
\ncountries since 2003 has required the killing of about 140
\nmillion chickens. In order to keep up with an increasing
\npopulation and growth in demand for protein, countries such as
\nIndonesia will have to increase livestock production which will
\nincrease the risk of livestock disease outbreaks. Following
\nthis tendency, it is very likely that these infections will be
\nlinked to wild animals.<\/p>\n
In July of this year, studies reported the first case of
\nsimian foamy virus (SFV) infection, a non-human primate-borne
\ndisease, in a person with known exposure to free-ranging
\nIndonesian macaques in an eco-tourism monkey attraction in Bali.<\/p>\n
Alarm warns foreign tourists not to have close contact with
\nmacaques in these kinds of premises. However, no risk awareness
\nis raised for local people who keep these monkeys as pets, or who
\nsell them in markets. In all the animal markets of Jakarta and in
\nother large cities in Java and other islands, macaques are
\ncommonly seen on sale either as pets or for human consumption. No
\nanimal disease control is carried out and no authority warns
\npeople of the risk of transmission of diseases.<\/p>\n
The poor hygienic conditions in these markets means a risk for
\nsellers, buyers, visitors and the entire environment. The close
\ncontact between people and animals and their diseases in the
\ncontext of any animal market is, arguably, a potential risk for
\nzoonoses to emerge.<\/p>\n
All these wild animals harboring pathogens would not be a
\nhazard to human beings at all if they were left alone in their
\nnatural habitats far away from humans. It's only when humans
\ncross the barrier and stand in the way of these pathogens that
\nthe risk of new disease emerges.<\/p>\n
Emerging Infectious Disease reports that some studies have
\nshown that closing down retail poultry markets in Hong Kong for
\none day per month reduced the rate of H9N2 avian influenza virus
\nin market birds. In the same terms, it seems reasonable to think
\nthat closing down animal markets would have an analogous effect
\nin the Indonesian context.<\/p>\n
The writer is a veterinarian based in Jakarta.<\/p>", "url": "https:\/\/jawawa.id\/newsitem\/the-threat-of-zoonoses-from-live-animal-markets-1447899208", "image": "" }, "sponsor": "Okusi Associates", "sponsor_url": "https:\/\/okusiassociates.com" }