In its weekly report on Zika virus developments, the World Health Organization (WHO) said today that the outbreaks continue to expand, with three more countries reporting an increased incidence of Guillain-Barre syndrome (GBS).
In other developments, Hong Kong scientists who compared the genetic patterns of the current outbreak strain with those of an earlier version of the virus found several changes, though the clinical significance isn't clear. Also, experts weighed in the need to learn more about the complication potential of the African strain and for strong countermeasure development.
WHO notes more spread, new developments
In a situation update today, the WHO acknowledged new reports of local transmission in Cuba and Dominica, raising the number of affected countries in the Americas to 33. Five Pacific-region countries and territories are also experiencing outbreaks.
The WHO also noted that 12 countries are now reporting an increased incidence of GBS or lab-confirmed Zika infections in those with GBS, up from 9 the previous week.
So far only French Polynesia and Brazil have reported an increase in microcephaly and other fetal malformations, but the WHO said a baby was born with microcephaly in Cape Verde, where an outbreak has been under way, and tests on samples from the mother and baby for Zika virus are pending.
The agency added that 165 pregnant women in Cape Verde with suspected infections are being followed and that 44 have already delivered their babies.
Among several other new developments, the WHO:
- Cited a new report of a 2014 Zika virus case in Bangladesh, based on a retrospective study, similar to those identified in Papua New Guinea in 2015
- Announced the release of two mobile apps to help Zika responders and health providers, with versions in Spanish and Portuguese due this week
- Released with its partners risk communication radio spots on Zika virus in English and Spanish
Gene comparison reveals changes
A research team based at the University of Hong recently compared the pre-epidemic and post-epidemic Asian-lineage Zika strains to look for any changes that might explain increasing reports of neurologic complications. They found several, though they said more studies are needed to assess the biological significance. They published their findings yesterday in Emerging Microbes and Infections.
When they compared phylogenetic trees, coding regions were the same except for the nonstructural 2B, with further analysis suggesting a recombination at the site with Spondweni virus. They also found a conformational change in the epidemic strain, along with 15 amino acid substitutions.
They concluded that mutations in other flaviviruses have been linked to changes in virulence, replication efficiency, and host tropism, for example, and that more studies are needed to sort out the significance of the changes in the epidemic Zika virus strain.
Commentaries cover Africa risk, research priorities
- In vitro studies published this month showing that Zika virus from the African lineage can infect and kill human neural progenitor cells and block their growth are concerning enough to prompt prospective studies to look for microcephaly in African outbreaks, Daniel Lucey, MD, MPH, an infectious disease expert with Georgetown University Medical Center, wrote in a commentary today in Health Security. He said Cabo Verde could face a microcephaly epidemic soon in the wake of its outbreak, and clinical and epidemiologic studies would be helpful there, despite which strain is involved. Expanded surveillance and testing in Africa would be useful, especially in the West African region to help differentiate the illness from mild Ebola infections.
- More aggressive actions are needed to stop the spread of emerging pathogens, and the underlying problem is a lack of sustained investments and support for developing new vaccines and medicine ahead of outbreaks, according to two Sanofi research and development executives in a Science Translational Medicine editorial yesterday. Gary Nabel, MD, PhD, chief scientific officer, and Elias Zerhouni, MD, president of the division, suggested five improvements, including stronger political will to support the countermeasures, better regulatory harmonization, and more use of public-private partnerships.
See also:
Mar 17 WHO Zika situation report
Mar 16 Emerg Microbes Infect report
