On Tuesday, the American Red Cross asked prospective donors who have travelled to Zika outbreak zones to wait for more than 28 days prior to donating blood, however, mentioned that the risk of the virus transmission through blood donations is ‘extremely’ low in the continental United States.

In a statement, the Red Cross said that the ‘self-deferral’ notice for blood donors is applicable on the ones who have travelled to Mexico, the Caribbean, or Central or South America in the previous four weeks.

The Washington-based nonprofit disaster relief agency also asked that donors who donate blood and then contract symptoms consistent with Zika in the time span of two weeks of donating must consult the Red Cross so that the product can be quarantined.

So far, cases of the Zika virus have been reported in over 30 countries and territories. It is a mosquito-borne illness associated with a dangerous birth defect known as microcephaly, identified by abnormally tiny head size, and to a fatal autoimmune disorder known as Guillian-Barre syndrome that can lead to paralysis.

The infection’s most common symptoms are flu-like, including aches and fever. Susan Stramer, a microbiologist for the Red Cross said that nearly 80% of infected people have shown no symptoms whatsoever. Moreover, there is no blood test for the detection of disease.

Even then, the Red Cross said in its statement that the risk of transmission via blood donation is very low in the continental US.

Stramer added that even in Hawaii, which is presently hit by an outbreak of other mosquito-borne tropical disease, known as dengue fever, the chances of contamination of the blood supply due to Zika is less as there has been no reported transmission in the islands.