Arkansas has a large Marshallese community, and they accounted for more than half of cases during a mumps outbreak their late last year.
The Marshall Islands was now battling at least a thousand cases of mumps, which was first discovered in March.
Jill McCready, who works for the Pacific Island Health Officers' Association, said travel advice was issued to Marshallese living in Arkansas in October, but this wasn't enough to keep the outbreak contained.
