By Alexandra Ulmer and Corina Pons
CARACAS (Reuters) - A fetus whose mother likely had the Zika virus suffered the rare congenital defect known as microcephaly and ultimately died, doctors said on Friday, in the first Venezuelan case linking the infection to damage in babies.
The mosquito-borne virus has been linked to thousands of suspected cases of microcephaly in Brazil, and a recent study has suggested the virus may be associated with stillbirths.
The World Health Organization declared Zika an international health emergency on Feb. 1, citing a "strongly suspected" relationship between Zika infection in pregnancy and microcephaly, a condition in which an infant's head is markedly smaller than those of other babies of similar age and gender.
Public health officials say that link is growing stronger with new evidence, but expect it could take years to prove a connection.
In the Venezuelan case, the unidentified 24 year-old woman from the hot, oil-rich state of Monagas suffered a skin rash and general malaise during the thirteenth week of her gestation in January, according to a report by doctors from the Central University of Venezuela (UCV).
Some symptoms of Zika include a mild fever, skin rash, conjunctivitis, muscle and joint pain and fatigue, though as many as 80 percent of those infected never develop symptoms.
Nearly four months into the woman's pregnancy, a scan revealed that the fetus' heart had stopped beating. The dead fetus was diagnosed with microcephaly and there was a deficiency in the amount of amniotic fluid.
"Initial results... undertaken in the blood and the umbilical cord, as well as the amniotic fluid, reveal the presence of Zika's genetic material in these tissues," the report says.
The woman tested negative to cytomegalovirus, rubella, dengue and chikungunya, the doctors added.
Further information was not immediately available. The Health Ministry did not respond to requests for comments.
Venezuela last month said that suspected cases of Zika had risen to 5,221, one of only two official estimates on the virus that is rapidly spreading through the Americas.
Doctors say Venezuela actually has a far greater incidence of Zika and accuses the government of not doing enough to combat the outbreak.
An economic crisis in the OPEC country has meant that insect repellent, reagents to detect the virus, and fever relievers are running short. A scarcity of birth control pills has also led to unwanted pregnancies in Venezuela, where abortion is banned unless a woman's health is at risk.
President Nicolas Maduro's administration has not reported any cases of pregnant Venezuelans with the virus.
Infectious disease specialist Julio Castro, who is closely tracking Zika, says he knows of no other cases of potential Zika-linked microcephaly in Venezuela.
(Writing by Alexandra Ulmer; Editing by Bernadette Baum)