Brazilian Health Minister Alexandre Padilla on Thursday warned that Rio de Janeiro faced a major dengue epidemic, although he said the virus strain prevalent was not fatal. \"I believe that Rio could this year face one of the worst dengue epidemics in its history, in terms of number of cases,\" he said in a television interview. Padilla said the dengue virus strain prevalent in Rio was not the most serious and was not fatal. The official Agencia Brasil said since the start of the year, 3,499 dengue cases have been recorded in Rio, compared with 2,322 last year, but none were fatal. The government said that nationally cases dropped 62 percent this year to 40,486. Dengue affects between 50 and 100 million people in the tropics and subtropics each year, resulting in fever, muscle and joint ache. But it can also be fatal, developing into hemorrhagic fever and shock syndrome, which is characterized by bleeding and a loss of blood pressure. The news comes as Carnival frenzy sweeps Brazil and the South American powerhouse prepares for a week of sizzling samba dancing, glittering parades and unabashed merry-making in Rio and other cities.