Nigerians are strongly advised against non-essential travel including inter-state travel. The NCDC is working in collaboration with the Port Health Services, Nigeria Customs Service and Nigeria Immigration Service to ensure enhanced surveillance at land borders and seaports. At the seaports, ships arriving are subjected to mandatory health screening and clearance by the Port Health Services. This particularly applies to ships that sailed from high-risk ports, have been at sea for less than 14 days and/or that have crew members who are ill. The NCDC has also developed and disseminated the guidelines for self-isolation.