A genomics study undertaken by Scripps Research recently uncovered a previously undiscovered and underreported outbreak of the Zika virus that hit Cuba in 2017, prompting scientists to call on health, academia, and government organizations to step up efforts to share and coordinate information.
“Given that undetected viral outbreaks have the potential to spread globally, I hope that this study will encourage utilizing both travel surveillance and genomic data–in addition to local reporting–for future surveillance efforts,” said Sharada Saraf, an undergraduate intern in the Andersen Lab and co-first author of the study.
Sharaf and his colleagues analyzed airline travel schedules, flight patterns, and cruise ship destinations to better piece together the 2017 situation. The outbreak was peaking in Cuba just as international fears of the disease were beginning to pass, two years after its dramatic debut in Brazil in 2015. Health agencies throughout the world had assumed the Zika epidemic was nearing conclusion by the end of 2016, but in Cuba, where an aggressive mosquito control campaign had likely helped keep Zika at bay as it hit other Caribbean nations, the disease was taking root. There was little in the way of reliable local case reporting, however, to notify international officials. The only clue was a steady stream of Caribbean travelers still contracting the disease when even the World Health Organization’s concerns had eased.
As a result, the Scripps team — in conjunction with Yale University, Florida Gulf Coast University, and other organizations — obtained blood samples from infected travelers who had visited Cuba and used genomic sequencing to reconstruct virus ancestry and outbreak dynamics.
“Infectious diseases such as Zika are global problems, not local problems, and greater international collaboration and coordination is critical if we are to stay ahead of looming threats,” said Dr. Kristian Andersen, associate professor at Scripps Research and director of Infectious Disease Genomics at the Scripps Research Translational Institute. “Through this study, we developed a framework for a more global, more proactive way of understanding how viruses are spreading. The traditional reliance on local testing may not always be sufficient on its own.”
Once they had established the age of the virus, the team they determined the timeline of the Cuban outbreak, then began parsing health data from various sources, which they proceeded to analyze and consolidate. They made that data, and the Zika virus sequence data, available in the aftermath. What the team cannot say, however, is whether the Zika outbreak is still ongoing — the discrepancies in the local report continue.
“So many serious diseases–not just Zika–are almost perfectly linked to fluctuations in mosquito populations, yet this type of data isn’t being collected or made available in most places of the world,” Andersen said. “Especially as mosquito populations and other animal reservoirs of infectious diseases increase due to climate change and an expanding human population, it is becoming critically important for governments to prioritize this type of proactive monitoring.”