Thursday, December 5, 2013

Zoonotic Diseases


An area that has not been specifically talked about in class is the increase in zoonotic diseases. Zoonotic diseases are spread between animals and humans. The type of infection is not specific. It can be bacterial, viral, parasitic, or fungal.  While malaria and dengue are zoonotic disease (1), the one that has been in the local news recently is animal influenza (aka bird and swine flu) (3). There is currently a bird flu strand name H7N9 that has now spread from China to Hong Kong. With this current strand of the 137 that have gotten sick, 45 have died (5). Like many other strands before it the worry is that it will mutate and become more contagious and spread.  There is currently no vaccination against this strand of influenza.
More often zoonotic diseases seem to be attracting more publicity in the media. It has appeared to me that there is an increase in the numbers of zoonotic diseases that have emerged. This could be due to the increase in contact between human and livestock populations. The increase in world travel and globalization could make it easier for the diseases to spread to areas faster than they used to as well (2). Another factor that could be leading to the increase in zoonotic diseases is the urbanization or deforestation of previously uninhabited areas. The movement of people to these new areas increase contact to arthropods that could expose humans to new viruses (2).
Not only can zoonotic diseases have an impact on the health of humans directly through sickness or death they can also effect the economy. The impact that zoonotic diseases can have on the food supply is illustrated in the case of Bovine spongiform encephalopathy (BSE) or colloquially known as mad cow disease. It emerged in the UK in 1986 and up to 1 million cattle may have been infected by 1997. In 1995 variant Creutzfeldt-Jakob disease (vCJD) first appeared and was believed to be caused by BSE infected cattle that was consumed.  People who contract vCJD slowly lose the ability to see, speak, or feed themselves due to brain damage (3). When it becomes known that a country has a case of BSE beef prices are hit hard locally and generally beef exports are banned from a country suspected of having a case of BSE. BSE has already extremely hurt the beef industry in the UK and also has hurt the US beef industry when a case was found in Washington in 2003 (4).  Should something similar happen in a developing country it could wipe out certain agricultural practices and damage economies.
While these zoonotic diseases have received media attention other diseases such as Leptospirosis (passed from rats) or brucellosis (passed from cattle, pigs, goats, sheep, and dogs) have not received the same publicity. In some cases there are treatments or vaccinations to prevent transmission. No matter where the disease is, increased coordination from experts in all areas will be needed to come together to find ways to prevent the spread of these diseases.

(5) http://healthland.time.com/2013/12/03/heres-what-you-need-to-know-about-the-bird-flu-case-in-hong-kong/

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