Chikungunya in the Americas: Updated Charts

Last Update: 13 July 2014 [Charts]
chik_in_USA1_7.20chik_in_USA2_7.20chik_in_americas_7.20Some observations from the PAHO/WHO and CDC ArboNET reporting data this week…
1. The United States experienced its first locally-transmitted case(s) in Florida! Given that Aedes genus mosquitoes are endemic to the state, it’s not really surprising… Seems to me that it was just a matter of time. Though there’s no way to know for sure, I think that New York might be next state to experience local transmission [endemic Aedes + 20 reported imports since June 2014]. It’ll be interesting to see what happens next on this front!
2. Weekly case counts are on the rise and show no sign of stopping anytime soon. My e-mentor and Twitter-colleague Dr. Ian Mackay asked me whether this is due to (seemingly) rapid rates of transmission… Or if it’s just a consequence of improved surveillance. I’m honestly not sure. I personally think a third option is also viable: misclassification of cases. The reality is that only 1-2% of the cases reported thus far have actually been laboratory-confirmed; the vast majority of cases are classified as chikungunya when they meet the following PAHO/WHO definition: “patient with acute onset of fever >38°C (101°F) and severe arthralgia or arthritis not explained by other medical conditions, and who resides or has visited epidemic or endemic areas within two weeks prior the onset of the symptoms”. It’s possible that some folks who meet all these criteria don’t have chikungunya at all and instead of some other disease – resulting in misclassification as chikungunya cases.

I’m curious to hear what others think about the steep increases in case counts we’ve been seeing lately in the Americas, as well as hypotheses on possible contenders for local transmission in the United States! Contact me if you’ve got some #SWAGs to share.


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