Brazilian soldiers were deployed last week in Rio de Janeiro to help local authorities fight against the worst ever outbreak of dengue fever.

During the past four months, more than 55,000 cases of dengue fever have been reported in Brazil. The disease, which has already been called epidemic, has killed 67 people this year in Rio, according to the state’s ministry of health, CNN Web site reports. Slightly less than half of the deaths were children under the age of 13, the ministry said.

Dengue fever – which is transmitted mainly by the Aedes aegypti mosquito – comes in several strains and is difficult to diagnose, according to the U.S. Centers for Disease and Control. The disease is also known as “bone-break fever” and often causes severe joint pain, elevated body temperature, diarrhea, vomiting and bruising. People who suffer repeat infections from different strains run the risk of potentially fatal internal bleeding. No vaccine is yet commercially available. The disease cannot be spread by person to person.

Moreover, dengue hemorrhagic fever, one of the most severe forms of dengue “can be fatal if unrecognized and not properly treated,” Dr. Ali Khan of the CDC says. There are nearly 10 million cases of dengue worldwide each year, the CDC estimates.

"And unfortunately, over the last 30 years or so, we've seen an increase in the number of countries infected with dengue fever," Dr. Khan said.

Three new military field hospitals were set up in Rio and, according to state officials, they should help ease the shortage of hospital beds and take some of the pressure off emergency rooms packed with victims of the mosquito-borne disease.

“We have to enter into combat like we’re fighting a war, to minimize the suffering of the population,” said field hospital commander Maj. Roberto Tury, according to the same source.

Rio Mayor Cesar Maia said patients from outside the city are flooding the municipal hospital and there aren’t enough beds to accommodate them, Brazilian newspaper O Globo reported.

This is the reason why, more than 2,000 people, including members of the Ministry of Health and the military, arrived in Rio this week to help fighting against dengue, by spraying insecticide in hard-hit neighborhoods and by setting up emergency hospital tens, Brazil's Health Minister Jose Gomes Temporao said. Also, they inform people on the disease and ways they can avoid infection.

People are recommended wear long pants, socks and shoes, not sandals and use good insect repellant to prevent mosquito bites.