A seafarer infected by any of common mosquito-borne diseases may initially experience fever with mild non-specific symptoms similar to those of influenza and other febrile illnesses. As severity and treatment varies between diseases, immediate medical attention should be sought to ensure early diagnosis.

Most common Symptoms of Mosquito borne / transferred diseases


Sleeping quarters, mess rooms and dining rooms, indoor recreational areas, as well as all food spaces, should be effectively screened when vessels are in transit in areas where flies and mosquitoes are prevalent. Screening of no more than 1.6 mm spacing is recommended and care should be taken to screen all outside openings. Screens should not affect the safe opening of the door/hatch or porthole.

Standing Water

The best place for mosquito growth and development is the standing water. Areas with standing water should be adequately cleaned up and drained. Swimming pools, mooring line areas, drain drums, garbage drums are examples of potentially standing water development. The length of the mosquito life cycle varies between species and depends on area’s temperature and moisture. The life cycle of all mosquitoes is comprised of the egg, larval, pupal and adult stages. Eggs will hatch into larvae within 24 to 48 hours. Within seven to 10 days, larvae enter the pupal stage.

After a mosquito is fully developed, it will emerge as an adult from its pupal case. At this time, the new adult stands upon the water and dries its wings to prepare for flight. Larvae and pupae usually cannot survive without water. If a water source evaporates before the larvae and pupae within it transform into adult mosquitoes, those young often will die.


  • When working outside, such as in ports where mosquito-borne diseases occur, use insect repellent lotions on exposed skin.
  • At night, have the crew sleep under pyrethroid-treated bed nets
  • Do not use space spraying to control mosquitoes
  • Do not allow crew to rely on insect repellents other than those provided by vessel, in accordance with International Medical Guide for Ships.