Health officials in the United States have confirmed the first case of screwworm infestation to be observed in the country. The screwworm infestation comes from a female fly that lays its eggs in an open wound of a live human or other warm-blooded animal. Travelers bound for those regions should be careful not to sleep outside in rural areas where livestock are housed. The CDC advises doctors with patients who present with a screwworm infestation to notify their state health regulators. Travelers bound for destinations with outbreaks or infestations can review the risks and current threat levels at the CDC website.