US faces major Zika virus outbreak risk in summer: Study

The conditions in a number of US cities will become favourable for a possible Zika virus outbreak during the peak summner months, warns new research.

The Aedes aegypti mosquito, which is spreading the virus in much of Latin America and the Caribbean, will likely become increasingly abundant across much of the southern and eastern US as the weather warms, the study said.

"This research can help us anticipate the timing and location of possible Zika virus outbreaks in certain US cities," said lead author of the study Andrew Monaghan from US National Center for Atmospheric Research (NCAR).

"While there is much we still don't know about the dynamics of Zika virus transmission, understanding where the Aedes aegypti mosquito can survive in the US and how its abundance fluctuates seasonally may help guide mosquito control efforts and public health preparedness," Monaghan noted.

Summertime weather conditions are favourable for populations of the mosquito along the East Coast as far north as New York City and across the southern tier of the country as far west as Phoenix and Los Angeles, according to specialised computer simulations by the researchers.

Spring and autumnl conditions can support low to moderate populations of the Aedes aegypti mosquito in more southern regions of its US range. Wintertime weather is too cold for the species outside southern Florida and southern Texas, the study found.

By analysing travel patterns from countries and territories with Zika outbreaks, the research team further concluded that cities in southern Florida and impoverished areas in southern Texas may be particularly vulnerable to local virus transmission.

The results were published in the journal PLOS Currents: Outbreaks.

First identified in Uganda in 1947, the Zika virus has moved through tropical regions of the world over the past decade. It was introduced into Brazil last year and spread explosively across Latin America and the Caribbean, with more than 20 countries now facing pandemics.

Monaghan, however, stressed that even if Zika establishes a toehold in the mainland United States, it is unlikely to spread as widely as in Latin America and the Caribbean. This is partly because a higher percentage of Americans live and work in air-conditioned and largely sealed homes and offices.