Chikungunya in North America: "one million cases in the first ninety days!" HT: Croft.
Via chapelboro.com, a thought-provoking post by Jeff Danner: Chikungunya is Coming: Part I. Click through to read the whole thing. Excerpt, with the author's graphics:
The first ever recorded case of locally-transmitted chikungunya in North or Central America occurred on the island of St. Martin in December of 2013. Since then, an epidemic has spread like wild fire, particularly in the Dominican Republic. The Graph below shows the number of infections reported during the first ninety days of the epidemic in the Dominican Republic, with day zero being April 1 of 2014.
In the first 90 days of the epidemic, this nation of 10 million people had 135,000 cases! If the behavior of this epidemic follows the pattern of the outbreak on Reunion Island in the India Ocean from 2005-2006, the Dominican Republic can expect approximately two to four million cases of chikungunya to occur within a year.
To put it lightly, an epidemic of this proportion will be very challenging and disruptive to the citizens and economy of the Dominican Republic. Overall, there have been over a quarter of a million cases in the Caribbean, including Puerto Rico and the U.S. Virgin Islands, in the first six months of 2014.
Now let’s consider the probability of a chikungunya outbreak in the continental United States. For starters, essentially zero percent of the population of the United States is immune to chikungunya. Next consider the maps below showing the current ranges of Aedes aegypti and Aedes albopictus in the U. S.
As you can clearly see, both species of mosquito are resident in large portions of the country, including North Carolina.
For the purposes of the calculations below I estimated that approximately 25% of the U.S. population lives within the current range of one or both of these mosquitoes. All that is needed for an epidemic to get started is for one or more infected people to arrive here on boats or planes and the mosquitoes to bite them at the right time.
The data on this front is not encouraging. According to the Centers for Disease Control (CDC), so far this year there have been 138 confirmed cases of people arriving in the continental US, primarily returning vacationers, with a chikungunya infection acquired while abroad. This number is unprecedented. So far we have been extremely lucky that there have been no reported cases of local transmission.
While my position is that current conditions make a near-term chikungunya epidemic in the U.S. almost certain, the statement made by the CDC on their website is more measured. Their position is, “There is a risk that the virus will be imported to new areas by infected travelers.” Therefore, either I am being alarmist or they are too concerned about creating a panic to be more forthright about the risk.
If I am correct and the Southeastern United States is about to have an epidemic similar to the one in the Dominican Republic, we’d have one million cases in the first ninety days! That would make for a few headlines.
So is there anything we can do to prevent this? Should we have been more prepared that we are? For my thoughts on that, you need to come back next week. In the meantime, I’d think about stocking up on insect repellent.
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