(CBS) — A potential blood shortage could be on the horizon as blood banks are forced to turn away donors who have traveled to areas of high risk for the Zika virus.

CBS 2’s Mai Martinez talked with one of the largest blood banks in our area about the impact on Chicagoland.

When it comes to blood drives, the more donors the better.

“There’s always a need for blood,” said Tammy Winchester, senior blood consultant for Heartland Blood Centers. “It’s constant. Patients are in need in surgeries every day.”

Heartland Blood Centers serves more than 70 hospitals in the Chicago area.

“There’s always a blood shortage is what I say,” Winchester said. “Right now we are in need O-neg and A-neg.”

In the winter, that shortage is even greater because of the flu and holiday travel, but this year, the Zika virus is putting an added strain on the blood supply.

As a precaution, people who have traveled to at-risk areas including Mexico, the Caribbean, Central America and South America are being asked to wait 28 days before donating.

“The concern is will their blood be infected?” Winchester said. “Will they impact patients? Are they still able to donate? And how long?

In the past week alone, Winchester had to turned away about 20 donors who recently traveled to at-risk areas.

Winchester says in the past week, she’s had to turn away about 20 donors. She says a pint from one donor could possibly save three lives, but that it’s tough to gauge knowing many surgeries require dozens of pints of blood per patient.

When asked if there is a concern the Zika virus will put a critical strain on the blood supply, Winchester says, “It is a concern because so many people have traveled and still traveling.”

Winchester says it’s too early to tell what the long-term impact of the Zika virus will be on blood donations, but that makes it even more important that people donate now.

If you’d like to, there’s a link to upcoming drives, visit www.heartlandbc.org/find-by-city-2/.