A health travel warning to the Madeira Islands off Portugal was issued by the Health Ministry on Monday after it received reports of dengue fever there.The disease, which has flu-like symptoms such as fever, headaches, muscle and joint aches, a rash and digestive disruptions, is spread by mosquito bites. It can also cause hemorrhages, and in one percent of cases, it can be fatal. The ministry recommended that anyone going to the islands take precautions against mosquito bites both outdoors and indoors and at any time of the day by wearing long-sleeved clothing and using anti-mosquito spray or roll-ons.