Hawaii officials closed a Big Island road, campground and hiking trail in an effort to stop the spread of a dengue fever outbreak that had sickened 223 residents and visitors as of Friday (Jan. 15), the Maui News reported.

Five of those cases could be potentially infectious, according to the Hawaii Department of Health.

The Department of Land and Natural Resources closed the Muliwai hiking trail on the far cliff side of Waipio Valley and its Waimanu Valley campground on Friday.

Hawaii County’s Civil Defense Agency blocked all traffic to Waipio Valley Access Road on Thursday and limited access to residents. The road closure comes three weeks after health officials closed access to state lands near Milolii and Honomalino Bay, which were “hot spots” for the mosquito-borne virus.

The agency sprayed the area to kill the insects and met with residents and local tour operators, said Darryl Oliveira, Hawaii County’s civil defense administrator. So far, health officials have not identified other potential problem areas, he said.