Nav: Home

Seven months after Rio Olympics, Zika continues to plague babies in urban slums

March 23, 2017

Many international travelers to the 2016 Summer Olympics in Rio De Janeiro, Brazil, openly considered skipping the games to avoid the threat of Zika. Despite the fears, not a single case of Zika or its major neurological complication, microcephaly, was reported by foreign visitors. The near-paranoia -- and the diversion of scarce resources to protect a low-risk population -- could have been avoided by heeding the lessons of previous epidemics, argues a new study from public health researchers at UC Berkeley.

The researchers analyzed the burden of diseases that are similar to Zika and found that seasonal patterns in their spread foreshadowed Zika's decline leading up to the games. As Zika tapered, and news coverage of the epidemic became less frequent, the truly vulnerable people became invisible, according to the study. Both during the games and today, mothers living in Rio's sprawling urban slums give birth weekly to microcephalic babies (children born with abnormally small heads and a range of other complications).

"Zika is just another example of how populations that reside in these urban slum communities are ignored, neglected and invisible," said study author Lee Riley, a professor in the Berkeley School of Public Health, who has spent nearly 25 years studying urban slums in Brazil. "What happened with Zika is just like what happened with the spread of Ebola; nobody said a word about it in urban slums."

The study was published Thursday in the journal PLOS Neglected Tropical Diseases. The research was a collaboration with their colleagues Claudete Araújo Cardoso, Fabio Aguiar-Alves and Felipe Neves at the Universidade Federal Fluminense in Brazil.

Except for sporadic reports, Zika is a disease of the urban poor. Slum-defining characteristics such as poor water and sanitation infrastructure, crowding and poor structural quality of housing offer ample opportunities for mosquitoes to breed and spread the Zika virus. The species of mosquito that most commonly transmits Zika will, on average, travel a mere 100 meters in its lifetime. In the densely populated slums of Brazil, a single 100-square-meter space could contain more than 100 housing structures, up to three stories high, with a resident population upwards of 1,000. These residents can be infected multiple times by mosquitoes circulating in such neighborhoods.

Yet during the Rio Games, the world's attention focused on issues related to tourists. Wealthy residents or tourists in high-rise apartment buildings with screened windows, air conditioning and regular spraying of insecticides, even if located adjacent to these slums, are less likely to be exposed to such mosquitoes.

To illustrate how Zika fears were misplaced, and to offer one example for how the public-health community can use data to better understand future epidemics, the study compared other mosquito-borne diseases carried by the same mosquito that carries Zika, such as dengue virus. The study showed that peak incidence of these diseases in Brazil occurred during the hottest and wettest months. Because August is a winter month in the Southern Hemisphere, incidence of the diseases plummeted around this time. Even the Brazilian Ministry of Health's most recent Epidemiologic Bulletin reported no new cases in Rio de Janeiro between early August and September. Taken together, these data suggest that Zika infections would have tapered off well before the Olympics, which is just what happened.

"Our study suggests that if we had looked at whether or not Zika would be a problem using previous epidemiological evidence, we would not have wasted energy or effort worrying about tourists getting Zika," said Robert Snyder, the study's lead author and program manager for the Center for Global Public Health.

Snyder, Riley and study co-author Claire Boone each spent time in Brazil, studying infectious diseases that predominate in urban slums. Boone, a master's student, was awarded a Center for Global Public Health fellowship to spend the summer of 2016 prior to the games conducting research in Brazil.

Predictive models suggest the ongoing Zika epidemic may run out of steam after two or three more seasons, but these models do not consider how urban slums and their highly mobile populations affect the disease's dynamics, according to the study.

"One of the biggest questions with Zika is, what is the future going to be like?" Snyder said. "We have no idea what the characteristics of this disease moving forward will be."

The energy, media attention and research resources revolving around the Zika virus epidemic must be harnessed and used to bring the largely ignored urban slum populations of megacities around the world into the global spotlight, the study argues.

"If the public-health community had looked at the examples of previous epidemics, maybe we could have invested more effort in helping the people in urban slums who are actually being affected by Zika," Snyder said.
-end-


University of California - Berkeley

Related Public Health Articles:

The Lancet Public Health: Ageism linked to poorer health in older people in England
Ageism may be linked with poorer health in older people in England, according to an observational study of over 7,500 people aged over 50 published in The Lancet Public Health journal.
Study: Public transportation use linked to better public health
Promoting robust public transportation systems may come with a bonus for public health -- lower obesity rates.
Bloomberg American Health Initiative releases special public health reports supplement
With US life expectancy now on the decline for two consecutive years, the Bloomberg American Health Initiative is releasing a supplement to Public Health Reports, the scholarly journal of the US Surgeon General.
Data does the heavy lifting: Encouraging new public health approaches to promote the health benefits of muscle-strengthening exercise (MSE)
According to a new study in the American Journal of Preventive Medicine, almost 75 percent of US adults do not comply with public health guidelines recommending two or more muscle-strengthening exercise (MSE) sessions a week, with nearly 60 percent of the population doing no MSE at all.
The Lancet Public Health: Moderate carbohydrate intake may be best for health
Low-carb diets that replace carbohydrates with proteins and fats from plant sources associated with lower risk of mortality compared to those that replace carbohydrates with proteins and fat from animal sources.
Mass. public safety, public health agencies collaborate to address the opioid epidemic
A new study shows that public health and public safety agencies established local, collaborative programs in Massachusetts to connect overdose survivors and their personal networks with addiction treatment, harm reduction, and other community support services following a non-fatal overdose.
Cyber attacks can threaten public health
Gordon and Landman have authored a Perspective piece in the New England Journal of Medicine that addresses the growing threat of attacks on information systems and the potential implications on public health.
Public health guidelines aim to lower health risks of cannabis use
Canada's Lower-Risk Cannabis Use Guidelines, released today with the endorsement of key medical and public health organizations, provide 10 science-based recommendations to enable cannabis users to reduce their health risks.
Study clusters health behavior groups to broaden public health interventions
A new study led by a University of Kansas researcher has used national health statistics and identified how to cluster seven health behavior groups based on smoking status, alcohol use, physical activity, physician visits and flu vaccination are associated with mortality.
Public health experts celebrate 30 years of CDC's prevention research solutions for communities with health disparities
It has been 30 years since CDC created the Prevention Research Centers (PRC) Program, currently a network of 26 academic institutions across the US dedicated to moving new discoveries into the communities that need them.
More Public Health News and Public Health Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

In & Out Of Love
We think of love as a mysterious, unknowable force. Something that happens to us. But what if we could control it? This hour, TED speakers on whether we can decide to fall in — and out of — love. Guests include writer Mandy Len Catron, biological anthropologist Helen Fisher, musician Dessa, One Love CEO Katie Hood, and psychologist Guy Winch.
Now Playing: Science for the People

#543 Give a Nerd a Gift
Yup, you guessed it... it's Science for the People's annual holiday episode that helps you figure out what sciency books and gifts to get that special nerd on your list. Or maybe you're looking to build up your reading list for the holiday break and a geeky Christmas sweater to wear to an upcoming party. Returning are pop-science power-readers John Dupuis and Joanne Manaster to dish on the best science books they read this past year. And Rachelle Saunders and Bethany Brookshire squee in delight over some truly delightful science-themed non-book objects for those whose bookshelves are already full. Since...
Now Playing: Radiolab

An Announcement from Radiolab