Eighty nine Americans have been diagnosed with chikungunya after returning from trips abroad this year, and not one of them caught it at home. Federal surveillance data current through August 11 show 89 travel-associated cases reported to the national arbovirus system from US states, plus one in a US territory, and zero locally acquired cases anywhere in the country.
That combination is the whole story. The virus keeps arriving in the United States inside returning travelers, and so far this year it has not established itself in local mosquito populations the way dengue has in parts of Florida. The pattern shifts the risk from a neighborhood question to a trip planning question.
