Ebola Lessons learned? Global organizations speed Zika R&D

Print 29 January 2016
Nuala Moran / BioWorld

LONDON – Forces are starting to be marshaled against the Zika virus, with researchers calling for the experience of the Ebola crisis to be applied in expediting clinical trials of potential treatments and diagnostic tests for the newly rampant virus.

"[This] is an important emerging disease outbreak situation and we really must apply the lessons we learned from Ebola, because Zika could be a major public health issue," said Trudie Lang, director of the Global Health Network at Oxford University.

Lang, who was involved in setting up field trials of treatments for Ebola in West Africa, said studies of possible treatments for Zika are needed as soon as possible.

"During the Ebola outbreak the research response was too slow," Lang said. "Research simply must be embedded in the global response to emerging outbreaks such as [Zika]."

The international research community is pulling together through the International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC) network to support local health research groups to set up studies as quickly as possible, by sharing research methods and protocols, said Lang.

ISARIC, based in Oxford, is a global initiative aiming to ensure that clinical researchers have the open access protocols and data-sharing processes needed to facilitate a rapid response to emerging diseases that may turn into epidemics or pandemics.

Meanwhile, the U.S. National Institute of Allergy and Infectious Diseases issued a notice highlighting possible opportunities for funding Zika research. It is interested in funding work to understand infection, replication, pathogenesis and transmission of Zika, and the development of animal models, diagnostic tests, drugs and vaccines against the virus.

The call to speed up research and clinical studies came as the World Health Organization (WHO) issued an alert warning the Zika virus is likely to spread to all countries in North and South America where the Aedes mosquito vector is found.

Following the first reported case in the Americas, which occurred in Brazil in May 2015, the virus had reached 21 countries in the region as of Jan. 23.

While the role of the Aedes mosquito in transmitting Zika is well understood, there is little conclusive evidence on other aspects of the virus, nor any specific diagnostic or treatment for the fast-spreading infection.

R&D efforts may be ramping up, but for now WHO is limited to giving traditional advice on preventing or slowing the spread of Zika by controlling mosquito populations and avoiding mosquito bites.

Zika is not readily passed from human to human. However, it can be transmitted through blood and has been isolated in human semen, with one case of possible sexual transmission, though more evidence is needed to confirm this, WHO said.

Similarly, more evidence is needed of whether mother to child transmission is possible in pregnancy or through breast milk.

Although Zika typically causes only mild symptoms, it has been linked to an unfolding public health emergency in Brazil, where there is a marked increase in microcephaly in newborn babies. A total of 3,863 cases of microcephaly have been reported from 21 Brazilian states, more than a 20-fold increase compared to the average number of annual cases reported from 2010-2014.

In addition, several Zika-affected countries have reported unusual increases in Guillain–Barré syndrome.

Zika is named after a forest in Uganda, where it was first detected in a monkey in 1947. The first human cases were identified in Nigeria in the late 1960s. From there it spread gradually to Southeast Asia.

EXPLAINING THE RAPID SPREAD

WHO attributed the rapid spread since reaching Brazil to the fact that the population in the Americas has not been exposed previously and so lacks immunity to Zika, and that the Aedes mosquito vector is widespread.

Potential factors enhancing transmission are the high population density in large cities and the large number of breeding sites for the Aedes mosquito, said Laura Rodrigues, professor of infectious disease epidemiology at the London School of Hygiene and Tropical Medicine. "[Aedes] is a domestic mosquito and is rarely found more than 100 metres from human habitation," she said.

Rodrigues, who is a Brazilian, said evidence for a link between contracting Zika during pregnancy and microcephaly is relatively strong, noting the virus is neurotrophic. "It grows in the brain of the fetus and destroys brain structures," she said.

Until a few months ago it was not known Zika could cause microcephaly, Rodrigues noted.

"It caught us all by surprise," she said. "There was very little research as Zika was seen as a virus of no public health importance. There is no vaccine. We do not know if a case becomes immune. There is no good diagnostic test and no treatment. Much more research needs to be done."

In a speech on Monday, Margaret Chan, director general of WHO, said the "explosive spread" of Zika to new geographical areas is a cause for concern.

Following criticism of its reaction to the Ebola epidemic, WHO is in the process of setting up a new program for handling infectious disease outbreaks. An expert group appointed to advise on its structure delivered its report last week. Chan promised the lessons from Ebola will be applied to strengthen WHO's response in future.

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