Infection with Rift Valley fever virus was associated with a sevenfold increased risk for miscarriage in pregnant women in Sudan, according to a recent study.
“Outbreaks of Rift Valley fever lead to mass abortions in livestock, but such abortions have not been identified in human beings,” the researchers wrote in The Lancet Global Health. “Our aim was to investigate the cause of miscarriages in febrile pregnant women in an area endemic for Rift Valley fever.”
According to WHO, Rift Valley fever virus (RVFV) can cause severe disease in animals and humans. Mosquitoes can transmit the virus, but humans are most often affected through contact with the blood or organs of infected animals, WHO says. The virus is almost always documented in Africa, although confirmed cases appeared in Saudi Arabia and Yemen in 2000.
The researchers tested patient samples from 130 pregnant women who attended a government hospital in Port Sudan between June 30, 2011, and Nov. 17, 2012, and had a fever of unknown origin.
Among the women diagnosed with RVFV (n = 28), 54% had miscarriages, compared with 12% of those not infected with RVFV (n = 102). Multiple logistic regression analyses showed that RVFV infection was an independent predictor of having a miscarriage (OR = 7.4, 95% CI, 2.7-20.1), the researchers wrote.
In a related editorial, Ali S. Khan, MD, MPH, dean of the department of epidemiology, and Carl V. Smith, MD, professor of obstetrics and gynecology, both from the University of Nebraska Medical Center, wrote that knowledge of RVFV is decades-old — and the disease has perhaps been around since Biblical times. Still, they said, revelations about it continue to be made, including the first two reports in this century of vertical transmission.
“The observation of spontaneous abortion due to Rift Valley fever is timely given the experience with two other emerging infections: Zika in the Americas and Ebola in West Africa,” they wrote.
Khan and Smith said it was premature to alert pregnant women about areas of endemic RVFV, but that caution should be taken to prevent mosquito bites. They also wrote that further investigations are needed to determine if RVFV should be added to the list of diseases that cause adverse pregnancy outcomes. – by Gerard Gallagher
Disclosure: The researchers report no relevant financial disclosures.