The Allegheny County Health Department confirmed the fourth local case of Zika virus since the end of March on Thursday.

Three weeks ago, a Pitt researcher accidentally stuck herself with a needle contaminated with Zika virus, according to a Pitt statement. A week later, she developed symptoms of Zika infection — which commonly include fever, rash, joint pain and redness of the eyes — and a blood test last Wednesday confirmed the Zika diagnosis.

Zika virus usually spreads through mosquito bites or sexual activity, but a needle can also introduce the virus into the bloodstream.

While Zika is not a debilitating disease in adults, research suggests that contracting the virus during pregnancy can lead to a severe congenital brain malformation, called microcephaly, in newborns.

The afflicted Pitt researcher no longer has any Zika symptoms, but she is wearing long-sleeve clothing and insect repellant to avoid mosquito-borne transmission of the virus, Pitt said.

According to Karen Hacker, director of the ACHD, “… despite this rare incident, there is still no current risk of contracting Zika from mosquitos in Allegheny County.”