After four patients in Florida tested positive for the Zika virus. infectious disease experts say that it could soon be spreading to  Louisiana and Texas.

But health officials also said they do not expect outbreaks of the size seen in South and Central America, primarily because of better sanitation, mosquito control and wider use of window screens and air conditioners.

Though Florida Governor Rick Scott is urging tourists not to change their travel plans, some medical experts say pregnant women should not travel to the Miami area. The Center for Disease Control is not issuing such advice. The CDC is warning, however, that pregnant women in the Miami area should be tested.