Dengue fever has left at least 67 people dead, including 40 children, in the state of Rio since January this year, Xinhua quoted local media as reporting. Thirteen new deaths caused by the disease were reported Monday in the state, where some 45,000 dengue cases have been registered since January, surpassing the total number of 2007. The Brazilian armed forces started services in several field hospitals Monday to help with the fight against the epidemic and promised to provide altogether 1,200 staff in the battle. According to Brazil's Ministry of Health, Rio has registered some 36 percent of all the 120,570 dengue fever cases in the country this year. Rio's State Secretary of Health Sergio Cortes announced that he will ask other state governments to send pediatricians to Rio, where local residents have complained about the lack of medical staff specialized in children care at hospitals. Dengue fever, a viral infection spread by the Aedes Aegypti mosquito, is a serious health problem in many American countries. Its symptoms include high fever, nausea, rash, backache and headache. Most mainstream dengue cases are not fatal, but the hemorrhagic type, which causes severe internal bleeding as blood vessels collapse, kills one in 20 of the infected. The World Health Organization said the only way to fight dengue is to stamp out mosquitoes, which reproduce in bodies of water from puddles to lakes and reservoirs. Some 50 million people are infected with the disease each year, mostly in the tropical regions.