Sunday, January 31, 2016
There’s Zika in our future. Count on it.
You’ve read lots about the Zika virus, another in the toxic deck of playing cards dealt by the Aedes aegypti mosquito, the yellow fever mosquito. Others include Dengue, Yellow Fever and Chikungunya.
Zika can also be carried by the Aedes albopictus mosquito, the Asian tiger mosquito.
We’ve got them in Hawai`i. Lucky Hawai`i, we are one of the first places on the planet to be invaded by both. They are both alien invaders. In pre-human Hawai`i, there were no native mosquitoes.
So far, only one person is known to have arrived in the islands with Zika, and it appears not to have spread from that case. The most likely source of the virus is in travelers returning from areas where the virus is rampant.
It’s in Samoa, and almost anywhere in the tropical and subtropical Americas. How widespread is it in the Americas? Check this list: Barbados, Bolivia, Brazil, Colombia, Dominican Republic, Ecuador, El Salvador, French Guiana, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Puerto Rico, Saint Martin, Suriname, U.S. Virgin Islands, Venezuela.
Oh, it just got reported this week in Jamaica.
There’s a lot of information about Zika at this Centers for Disease Control (CDC) site.
Zika is in a class of disease-causing organisms called flaviviruses. They include West Nile virus, dengue fever, tick-borne encephalitis and others.
The upshot is that the disease is not that big a deal for adults—certainly nowhere near as painful and symptom-filled as the dengue fever that’s now running through the Big Island. Primary symptoms are fever, rash, joint pain, or conjunctivitis (red eyes), muscle pain and headache. And most infected people—four out of five—have no obvious symptoms at all (although presumably they can still spread the disease.)
However, there are concerns that in some people an infection with Zika could lead to Guillain-Barré Syndrome, an immune system disorder. CDC notes that there are increased cases of Guillain-Barré in Zika infections, but they haven’t confirmed the relationship.
Same thing with birth defects. Pregnant women who get Zika in Brazil seem to have an increased rate of children born with microcephaly, or abnormally small heads, “and other poor pregnancy outcomes,” CDC says. There’s still far more to learn, but women are encouraged to avoid Zika infested areas if pregnant, or if likely to become pregnant, and to use precautions if they must be there.
Here are the precautions, but the basic rule is to do everything you can to avoid being bitten by a mosquito, including chemical mosquito repellants and protective clothing.
World Health Organization Director-general Margaret Chan last week convened an emergency panel, to meet Feb. 1, 2016, to look into the association between Zika and birth defects and Guillain-Barré. Here is her statement.
And there are all sorts of conspiracy theories running around already, as there were about AIDS and Ebola. One of them is that genetically modified mosquitoes are somehow involved in transmission.
The opposite is true. A number of initiatives are being used to determine whether genetically modified mosquitoes can be used to stop the virus, but they are happening after Zika already burgeoned. And a test of a genetically modified mosquito in one Brazilian city, Piracicaba, appears to have protected many residents there.
Zika appears to have changed its character and become more of an epidemic and less of a rare and isolated disease as much as 10 years ago, long before genetic modification techniques on mosquitoes were being attempted in Brazil.
To be clear, Zika was first identified in 1947 in the forests of Uganda in monkeys. It was found in 1952 in humans in Uganda and Tanzania. It popped up occasionally here and there as people moved it around the globe. It got to Southeast Asia in 1966, and by 1970 was in India, Pakistan, Indonesia and Malaysia.
It first appeared in the Pacific in Yap with a couple of hundred cases in 2007.
Zika had been rare and isolated before Yap. The Yap case was the first to be described as an outbreak.
The New England Journal of Medicine described the Yap cases in a paper in 2009.
“The virus could have been imported by a person with undetected infection. Serologic evidence of Zika virus infection in humans has been reported in the Philippines, and travel between Yap and the Philippines is common,” the journal article said.
In an ominous bit of prediction, the 2009 paper warned that this disease, the way it was behaving on Yap, was a threat throughout the Pacific as well as the Americas.
“The accessibility of air travel and the abundance of mosquito vectors of flavivirus in the Pacific region raise concern for the spread of Zika virus to other islands in Oceania and even to the Americas,” the paper said.
The outbreak in Tahiti/French Polynesia four years later was the largest known Zika flare-up in history.
One suggestion is that Tahitian canoe paddlers competing in the Va`a World Sprint Championship in Rio brought it to Brazil in August 2014. Here is a report on that.
It seems to be spreading in Brazil with the same ferocity as it did in Tahiti. It was reported as a full-fledged outbreak by mid-2015.
Here is a World Health Organization fact sheet on Zika.
Here is a fact sheet for health professionals on Zika from the European Centre for Disease Prevention and Control.
How bad could it be? In Tahiti in 2013, 35,000 suspected cases were reported, although far fewer were confirmed. There are fewer than 300,000 people in all of French Polynesia--so more than 10 percent of the population was possibly impacted.
Brazil alone has more than 200 million people, and the rest of South America has nearly that number. The World Health Organization reported Zika is spreading explosively through the Americas.
© Jan TenBruggencate 2016