Rousseff, in a taped national TV address, said the virus represents a real threat.
"Victory depends on our determination," Rousseff said, while emphasizing that the fight against the virus "is complex."
The President said her government is providing a large amount of human, financial and technological resources to fight the virus.
On February 13, about 220,000 Brazilian armed forces will take part in a campaign to fight the spread of the virus, Rousseff said.
The Zika virus is "now spreading explosively" in the Americas, the head of the World Health Organization said last week, with another official estimating between 3 million to 4 million infections in the region over a 12-month period.
The infection by itself is usually not dangerous, according to experts, but it has been linked to a condition called microcephaly, in which babies whose mothers are infected with the virus during pregnancy can be born with small heads and underdeveloped brains.
The virus is linked to an alarming spike in babies born with microcephaly in Brazil.
At least 404 -- almost three times the normal yearly total -- of babies were born with microcephaly in Brazil from November 8 through January 30, the Brazilian Ministry of Health said Wednesday. Seventeen of those cases have so far been linked to Zika, the agency said.
According to health officials, five infant deaths have been linked to Zika and microcephaly. Another 10 deaths attributed to microcephaly have not been associated with Zika. More than 50 infant deaths are still being investigated.
Emergency meeting among South American health officials
The Pan American Health Organization, or PAHO, launched an international appeal to fight Zika at a regional health summit.
"We estimate that we'll need some $8.5 million to adequately help our member states to respond," Carissa Etienne, the organization's director, told journalists at a meeting in Montevideo, Uruguay, on Wednesday. "We ask governments, and foundations, and other donors to help us with that money."
The organization has already spent more than $800,000, she said.
Health officials from 13 Latin American countries met in Uruguay on Wednesday in a hastily organized summit to coordinate the fight against Zika.
Despite Brazil's observation of sharp rises in birth defects, there were conflicting observations.
Colombia has so far reported the second highest number of microcephaly cases, but the increase hasn't been as high as expected, according to Colombia's minister of health.
"There is a major question mark," Colombian health minister Alejandro Gaviria Uribe said.
Gaviria Uribe said there was no rise in births with microcephaly so far in his country, but warned that the virus had only recently arrived.
French Polynesia reported a similar observation, according to Etienne.
Authorities expect the epidemic to reach many more in the Americas. Exactly how many is difficult to say because an estimated 75% of cases are relatively mild and go unreported, according to the PAHO.
The usefulness of recent fumigations across the world to combat mosquitos that carry the disease between people were questioned by PAHO's chief.
"Fumigation has high visibility -- high political visibility -- but we are not sure that it really is extremely effective in fighting the Aedes aegypti mosquito," Etienne said.
Larvae aren't killed by these procedures, leaving future generations of insects as a threat, Etienne said. Nevertheless, controlling mosquitoes and their bites is the only known prevention.
Officials agreed to create an emergency team to monitor the disease, according to a joint statement read by Uruguay Health Minister Jorge Basso. The statement also listed two other conditions transmitted by the mosquito as further causes for concern, namely, dengue and chikungunya.
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