President Dilma Rousseff says Brazil is trying to develop vaccine against the Zika and dengue viruses.

She says the Health Ministry is working with Brazilian and foreign laboratories to obtain a vaccine against dengue and the Zika viruses that are transmitted by the Aedes aegypti mosquito.

Brazilian officials have linked the Zika virus has been linked to the large number of cases of microcephaly, a rare birth defect.

The Health Ministry has said the number of cases of microcephaly has risen to 3,893 since authorities began investigating the surge in cases in October.

Rousseff also called on Brazilians to redouble their efforts to eliminate the mosquito and its breeding grounds.

Zika virus in pregnancy

A pregnant woman waits to be attended at a maternity hospital in Tegucigalpa, Honduras on Thursday. If a pregnant woman is infected by the Zika virus circulating in the country, the baby could be at greater risk for a rare birth defect called microcephaly. (Orlando Sierra/AFP/Getty)

She made her remarks on Thursday during a highway inauguration ceremony in the northeastern state of Pernambuco.

Some Canadian women who are pregnant have cancelled trips to the 20 affected countries and territories in South and Central America and parts of the Caribbean.

Last week, the Public Health Agency of Canada recommended that pregnant women and those considering becoming pregnant discuss their travel plans with their health care provider to assess their risk and consider postponing travel to areas where the Zika virus is circulating.

Doctors advise pregnant women who do travel to affected areas to cover up and use mosquito repellent.

With files from CBC News