The study discoverying of the hidding outbreak hints; that Zika virus can spread silently. 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 threat. Through this study, we developing 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; When the mosquito-borne Zika virus was discovering in Brazil during the spring of 2015; but it had already been circulating for at least a year, so this making its way to more than 40 countries, the study notes.
Very quickly, Zika ascended from a little-known virus to a source of international panic with worries accentuated by the fact that it could sometimes cause a severe condition known as microcephaly in babies born to women who contracted Zika during pregnancy. Coordinated response to Zika relied upon countries accurately detecting cases and reporting them to international health agencies.
Zika virus spread
By the end of 2016, data from these health agencies suggested that the epidemic was nearing its end. The virus subsequently fell off travelers radar; and the World Health Organization ended its designation of Zika as a Public Health Emergency of International Concern. However, researchers finding that an undetected outbreak was reaching its peak in Cuba at that time, off the radar of international health agencies.
Surprisingly, the outbreak lagged other Caribbean countries by a year, likely due to an aggressive mosquito control campaign that delayed the disease’s emergence, according to the study. The researchers noted that other infectious diseases spread by Aedes aegypti mosquitoes, including dengue, also were absent in Cuba at the same time. This expose an unknown outbreak when it began investigating travel-associated Zika cases in 2017.
Outbreaks in the Caribbean
The scientists simply wanted to know if the epidemic really was winding down. Instead, they found that a steady number of travelers from the Caribbean were still contracting the virus. With limited access to reliable local case reporting; the team devised a way to estimate local prevalence by obtaining blood samples from infected travelers who had visited Cuba; then using genomic sequencing to reconstruct virus ancestry and outbreak dynamics. The approach is known as genomic epidemiology.
By examining tiny genomic changes in each virus sample; The timeline determined that the outbreak in Cuba was established a year later than other outbreaks in the Caribbean. Study realizing there was a whole outbreak that had gone undetecting. Another major source of data came from travel surveillance. Together, the information painted a picture of how many people; visiting Cuba and other Zika-endemic countries during the time period in question.