Mosquito-Borne Rift Valley Fever Virus Linked to Miscarriage in Humans

Rift Valley fever virus (RVFv) has been linked to miscarriage in a cross-sectional study of pregnant Sudanese women with fever, which indicated a 7 times greater risk of miscarriage for infected women.

“In parts of Africa where there are RVF outbreaks, human miscarriages have never been linked to this particular viral infection, until now,” said co-author Magnus Evander, professor at Umeå University Faculty of Medicine (Umeå, Sweden), “With these results, we can add miscarriage to the list of known complications from RVF. This discovery is important for maternal health and for our efforts to develop preventive measures to minimize miscarriages, which are a big health problem for women in the affected areas of Africa.” The study was a collaboration between researchers at Umeå University, the Swedish Defense Research Agency (FOI), and clinicians in Sudan.


RVFv, mostly in Africa and on the Arabian Peninsula, regularly causes large outbreaks with hundreds of thousands of infected people and animals (e.g. cows, sheep, goats). RVF usually produces mild, influenza-like symptoms in humans, but in about 8% of cases, infected people develop serious symptoms, such as liver damage, serious eye infection, internal and external bleeding, meningitis, and death. In animals it often leads to death and as well as pregnancy miscarriages.

The new results are based on a study of 130 pregnant women with fever in Sudan, where outbreaks are a large and recurring health problem. Of the 130 patients, 27 had a miscarriage and 4 had premature births. The women infected with RVFv had a 7 times greater risk of miscarriage.

”Because RVF is caused by a mosquito-borne virus, there is a potential risk of global spread, which has been the case with the Zika virus. The fact that RVF could lead to miscarriage is very worrying,” said Prof. Evander.

The study was published September 27, 2016, in the journal Lancet Global Health.

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