(CNN) -- Soldiers and firefighters have joined the fight against dengue, a sometimes deadly mosquito-borne disease that has infected at least 55,000 people in Brazil this year.
"We have to go into this fight as if we are going into combat in order to minimize the population's suffering," said Maj. Roberto Tury, a field hospital commander.
The disease has killed 67 people this year in Brazil's Rio de Janeiro state, the state's Ministry of Health reported, and 58 other deaths are under investigation.
Almost half of those who died were children under the age of 13, the ministry said.
Dengue, or dengue fever, is common in Brazil and other tropical countries. Yet this outbreak is one of the worst in the region in recent memory, with an average of 1.4 new cases a minute, authorities said. Learn more about the disease »
Brazilian authorities call it an epidemic.
The Health Ministry said 21 people died from the more severe form of dengue, dengue hemorrhagic fever, or DHF.
Dengue hemorrhagic fever causes internal and external bleeding and is almost always fatal if untreated. The U.S. Centers for Disease Control and Prevention, however, said that with treatment, fatalities from DHF can be less than 1 percent of those infected.
Fourteen deaths were from dengue shock syndrome -- a form of DHF, but with signs of circulatory failure or shock -- and 32 were caused by the more common form of the disease, the health ministry said.
About 400 patients a day streamed into a military field hospital, and blood tests showed that 65 percent of them had dengue. Soldiers carried patients on stretchers while other patients stepped off buses.
"My eyes are hurting," one man said. "I'm dizzy. I have a headache and my back hurts."
Dengue is caused by four closely related viruses, all of which are carried by infected mosquitoes -- mainly the Aedes aegypti mosquito -- the CDC said. Watch a report on the outbreak »
It cannot be spread from person to person.
The Rio de Janeiro Health Ministry said 513 of its 57,010 cases of dengue were DHF.
The mayor of the city of Rio de Janeiro, Cesar Maia, said patients from outside the city are flooding the municipal hospital, and there aren't enough beds to accommodate them, the Brazilian newspaper O Globo reported.
The newspaper said hospital waits range from eight to 28 hours in some places.
One father told O Globo, "I am just watching my son die slowly as we knock on different hospital doors."
The state's secretary of health, Sergio Luiz Cortes da Silveira, acknowledged: "We don't have enough hospitals for these patients." He said the state is appealing for help from pediatricians elsewhere in the country. Watch ill Brazilians being cared for »
Brazil's Health Minister Jose Gomes Temporao said this week that 2,000 people, including members of the Ministry of Health and the military, were working to combat the Aedes Aegypti mosquito, the government reported on its Web site. At least part of this work, he said, included going door-to-door to educate people about preventing the breeding of mosquitoes.
"Without the mosquito, dengue does not exist," he said, according to the government.
Mosquitoes carrying dengue viruses breed in stored, exposed water, including places as shallow as jars, discarded bottles and plant saucers, according to the World Health Organization.
The CDC estimates there are up to 10 million cases of dengue around the world each year. "It actually is quite common," Dr. Ali Khan of the CDC said.
"And unfortunately, over the last 30 years or so, we've seen an increase in the number of countries infected with dengue fever," he said, blaming the increase in part on population growth. Mosquitoes that carry dengue typically breed in areas near humans.
"This is a disease that occurs where there's lots of population," Khan said. Watch Khan discuss dengue and its prevention »
He emphasized prevention. "Wear long sleeves, loose, baggy pants, and make sure you're using good insect repellent."
Symptoms of dengue fever include high fever, severe headache, backache, joint pains and eye pain, nausea, vomiting, and a rash, according to the CDC.
There is no vaccine to prevent dengue fever or DHF, the CDC said. E-mail to a friend
CNN's Harris Whitbeck and journalist Fabiana Frayssinet contributed to this report.