Zika virus fight a ‘long journey’—WHO chief

Brazil’s President Dilma Rousseff, right, and Director-General of the World Health Organization, Margaret Chan, pose for photo with a T-shirt of the mosquito eradication program, during a meeting at the Planalto Presidential palace in Brasilia, Brazil, Tuesday, Feb. 23, 2016. Chan is on a two-day visit to Brazil. AP Photo

BRASÍLIA, Brazil—The head of the World Health Organization warned Tuesday that the fight against Zika, a mosquito-transmitted virus linked to serious birth defects, will be long and complex.

“The Zika virus is very tricky, very tenacious, very difficult. And so is the Aedes aegypti mosquito,” WHO chief Margaret Chan said in the Brazilian capital Brasilia.

“We have learnt lessons from dengue and from chikungunya outbreaks in the past, so we should expect to see more cases, we should expect this is going to be a long journey.”

Brazil is at the center of a Zika outbreak and the virus is strongly suspected of causing a spike in microcephaly, a congenital condition that causes abnormally small heads and hampers brain development.

READ: CDC team in Brazil to study possible Zika link to defect

Cases of active Zika transmission have been reported in 28 countries and territories in the Americas and Caribbean, with 1.5 million in Brazil, the hardest-hit country.

Countries throughout the region have launched massive operations to eliminate pools of stagnant water where the mosquitoes, which also spread dengue and chikungunya viruses, can breed.

READ: Can scientists prove Zika virus is causing birth defects?

There is currently no cure or vaccine against the Zika virus.

The WHO had previously warned that the virus’s spread could be “explosive,” infecting up to four million people.