News Scan for Mar 01, 2017

Flu antivirals in pregnancy
;
Ebola deaths
;
Aedes aegypti and Zika

Review: Influenza drugs pose no risk to newborns

Neuraminidase inhibitors, the antiviral drugs given to fight and prevent influenza, pose no safety risks to fetuses or newborns, according to a new study published today in BMJ. This is the largest study on antiviral use and safety in pregnancy conducted to date.

The study was based on monitoring birth outcomes in 6,000 women in France and Scandinavia who were prescribed any of the two most common neuraminidase inhibitors, oseltamivir (Tamiflu) or zanamivir (Relenza), during pregnancy, and 700,000 women who did not receive prescriptions during a pregnancy in the same period (2008 to 2010).

Researchers found no evidence of negative birth outcomes, including low Apgar score, low birth weight, preterm birth, or birth defects among the women who took antivirals. The results were the same for either drug exposure.

"This study is by far the largest, being almost twice the size of all other studies combined with respect to the number of exposed pregnant women, and our results confirm and expand on the findings in the previous studies of no association between neuraminidase inhibitors and a broad range of adverse neonatal outcome," the authors write.

Pregnant women’s exposure to antivirals increased dramatically in 2009, during the H1N1 flu pandemic. Regulatory agencies in both Europe and the United States have routinely recommended using antiviral drugs to avoid complications from influenza infection in pregnancy.
Mar 1 BMJ study
Mar 1 BMJ press release

 

Malaria co-infection led to greater Ebola mortality, study says

According to a new study in The Lancet Infectious Diseases, Ebola patients co-infected with malaria were more likely to face increased mortality rates. The study was based on observations made at three Ebola treatment centers in Sierra Leone in 2014 and 2015.

The study looked at 1,524 cases admitted to treatment centers during the height of the 2013-2016 Ebola epidemic in West Africa. Of those cases, 1,114 patients tested negative for Ebola, but 365 (33%) were positive for malaria. Of the 254 patients with Ebola, 21% (53) also had malaria. For patents with both febrile diseases, mortality rates were high, about 66%. Patents with just Ebola suffered from a mortality rate of 52%.

Compared with patients who had neither malaria nor Ebola, mortality was increased in the malaria-positive and Ebola-positive group (adjusted hazard ratio 9.36), and the malaria-negative and Ebola-positive group (5.97), but reduced in the malaria-positive and Ebola-negative group (0.37).

The authors of the study said the results suggest the usefulness of treating malaria infections at Ebola treatment centers.
Mar 1 Lancet Infect Dis study
Mar 1 Lancet Infect Dis commentary

 

Scientists report varied Zika infection in Aedes aegypti mosquitoes

In a surprise finding, Zika researchers found that the African strain of the virus was more infectious than the Asian strain—which is responsible for the current outbreak in the Americas—and only Aedes aegypti mosquitoes from the Dominican Republic and not those from the United States or Brazil transmitted the Asian strain.

The international researcher group, led by investigators from the University of Texas Medical Branch at Galveston, used Zika virus strains from Senegal (the African strain) and Cambodia and Mexico (the Asian strain). They fed Ae aegypti mosquitoes from the three countries blood meals from viremic mice and used artificial blood that contained one of the three Zika strains.

The scientists found that, across all three mosquito populations, the African virus produced a significantly higher level of infection in the insects and a higher percentage of infectious saliva. They also found that only mosquitoes from the Dominican Republic transmitted the two Asian strains. The Cambodia strain was not transmitted at all by mosquitoes from Brazil after artificial blood meals, whereas 61% transmission occurred after a blood meal from infected mice.

The authors concluded, "Although some previous studies showed relatively low Zika virus competence in Ae. aegypti mosquitoes, raising questions about the role of other potential vectors, others have shown this species to be highly competent. We demonstrated that Ae. aegypti mosquito competency as a vector for Zika virus in the Americas varies greatly and depends on mosquito origin, Zika virus strain, and type of blood meal used."

They added, "Although regional origins of vector populations and virus strain influence transmission efficiency, Ae. aegypti mosquitoes appear to be competent vectors of Zika virus in several regions of the Americas."
Feb 28 Emerg Infect Dis study

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