Monday, August 27, 2012

Something Wicked This Way Comes


mosquitoes spread the disease

 During my teenage foray into science fiction I read a novel by Ray Bradbury by this name which scared my pants off. It is about a dangerous character Mr. Dark who comes to a small town with his maniac carnival. Sometime later I bumped into the original phrase whilst reading Shakespeare’s Macbeth in school: “By the pricking of my thumbs, something wicked this way comes” says Macbeth.


Something wicked is coming our way and in many ways it is invisible. It’s an array of scary diseases transmitted by animals.  These are know as zoonotic diseases. One which is making the news right now  is West Nile fever. This year's West Nile outbreak in the United States is on track to be the biggest ever since the virus first appeared in the US  in 1999. As of the third week of August, there have been a total of 1,118 cases of West Nile virus in people in 38 US States, including 41 deaths
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West Nile fever is unknown to most Seychellois. What is really scary is that the virus arrived in Seychelles some time ago and infected a substantial part of our population without anyone knowing it at the time. 

In 1997 it was found that almost 40% of individuals tested for Dengue, and other mosquito borne diseases surprisingly had antibodies against West Nile virus. This means that at some point in time these individuals were infected by the virus and developed immune responses. Researches speculate that West Nile virus arrived in Seychelles in epidemic waves rather then being endemic to the country.

Whilst it is a potentially serious illness only a few infected people will develop severe illness and about 20 percent of infected people who become infected have symptoms such as fever, headache, and body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash. In the US there have been 1,100 deaths reported since 2002.

West Nile fever is spread by the bite of an infected mosquito. Mosquitoes become infected when they feed on birds carrying the virus. Infected mosquitoes can then spread the disease to humans and other animals when they bite

But research in the US brings a positive twist to this tale. Scientists have found that in areas with high bird diversity, that is many different species especially native ones, there is a dilution effect where the proportion of suitable hosts for West Nile virus is reduced. High bird diversity is linked with low incidence of the virus in humans. http://tinyurl.com/9bqygy9

This is good news for some of our islands where conservation efforts led by BirdLife international, Nature Seychelles, private island owners and others have restored the habitats and increased the number of native bird species. These islands may be “immunized” against future epidemics of West Nile Fever. 

The moral of the story is to keep conserving our native environment so that if anything “wicked this way comes” it will be absorbed and diluted by the wonderfully diverse biodiversity we possess.

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