The Kalalau Trail on Kauai is expected to reopen fully to visitors on Tuesday after a recent norovirus outbreak that affected an estimated 50 people this summer.

State park officials had temporarily closed the trail and campsite at Napali Coast State Wilderness Park on Sept. 4 upon the advice of the Hawaii Department of Health. On Sept. 21, the trail was partially reopened up to Hanakapiai, for day use only.

“While it is not possible to ensure complete eradication of norovirus from the park or its facilities, substantial preventive measures have been taken during the closure,” said the Hawaii Department of Health in a news release. “Repeated disinfection of comfort stations, weeks of closure allowing natural processes (rain, UV light, virus degradation) to diminish remaining virus, and the cessation of new infections, give DOH and DLNR confidence that opening the park now is appropriate.”

During the closure, DOH said state crews also airlifted barrels of effluent from the Hanakapiai, Hanakoa and Kalalau composting comfort stations for treatment and disposal.

Health officials advise visitors to the reopened park, however, to take precautions by carefully washing hands with soap and water, treating water before drinking it and not visiting the park while ill.

The initial source of the outbreak was most likely a park visitor already infected with norovirus, according to DOH, who became acutely ill while at the park. An initial analysis points to “person-to-person spread and contact with contaminated comfort stations as highly suspected primary means of infection.”

Testing of water, sand and sediment samples from Kalalau Valley by the Centers for Disease Control and Prevention did not show any norovirus.

However, CDC tests found evidence of fecal contamination inside the cave near the campsite, which will remain closed through the winter.

State officials remind visitors it is against the law to urinate or defecate other than at the toilet facilities provided.

Norovirus is a very contagious virus that causes vomiting and diarrhea, often with fever, according to DOH.

It spreads in many ways, including:

>> Contact with an infected person while caring for them (they may have virus on their skin and clothing from vomiting and diarrhea).

>> Eating food or drinking liquids contaminated with norovirus (for example, if food or drink was prepared by someone who was sick or if it was shared with them).

>> Touching a surface or object that has norovirus on it and then touching your food or putting your fingers in your mouth (especially without thoroughly washing your hands with soap and water).

>> Sharing utensils or cups with people who are sick with norovirus.

To help prevent the spread of norovirus:

>> Wash hands carefully with soap and running water after using the toilet and before eating, preparing or handling food. Hand sanitizers alone do not work well against norovirus and should not be substituted for soap and water.

>> If you are sick, do not prepare food for others or care for others for at least two days after you recover. Throw out any food that may be contaminated with norovirus.

>> Clean and disinfect contaminated surfaces where anyone has vomited or had diarrhea using a chlorine bleach solution or other EPA-registered disinfectant effective against norovirus.

>> Thoroughly wash all contaminated clothing and bedding.

Visitors who develop symptoms of vomiting or diarrhea during or within 72 hours of a visit to the park are asked to notify DOH at 808-586-4586. If symptoms do not improve, DOH said, visitors should seek medical attention.