Colombia on Monday became the first nation in Latin America to declare that the “epidemic” stage of the much-feared Zika virus was over, even as a few hundred new cases emerge each week.
In addition, the Ministry of Health said there were far fewer cases than they originally feared last year, when the mosquito-borne illness began sweeping the region and was declared an international health emergency.
Since Zika was first detected along Colombia’s northern coast in September, 2015, it rapidly spread — resulting in 99,721 suspected cases so far.
The virus peaked early this year, when 6,312 new cases were reported during the first week of February. Since then, the number has dropped to fewer than 500 new cases per week and is expected to keep declining as Zika joins the ranks of Chikungunya and dengue as just another reality of living in the tropics.
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“This virus is here to stay,” Vice Minister of Public Health Fernando Ruíz said at a press conference. “In the future, we’re likely to see a small number of cases like we are seeing now with Chikungunya, but obviously there’s always the chance that we’ll see a new outbreak.”
Colombia has the second-highest number of suspected Zika cases in the Americas after Brazil.
As of July 14, the Pan American Health Organization had reported a total of 505,719 cases in the region with 165,932 of those cases occurring in Brazil.
The United States has seen 1,403 cases, with New York and Florida leading the nation with 345 and 270 respectively. Almost all the cases are attributed to travel to Zika-plagued areas, particularly the Dominican Republic. However, two Florida cases — in Miami-Dade and Broward — are being studied to see if they were transmitted by local mosquitoes.
Although the vast majority of those infected with Zika are asymptomatic, it can sometimes register as a mild flu and include rashes, joint pain and diarrhea. One of its most insidious effects is on pregnant mothers, who see an increased risk of giving birth to children with microcephaly, or abnormally small heads.
Colombian health officials said that of the 12,587 suspected Zika babies, 256 are microcephalic. But only 21 of those have been confirmed as Zika-related. An additional 160 remain under study.
Authorities were originally expecting 600 to 700 microcephalic births. Still, there’s an undeniable spike, said Martha Lucía Ospina, the director of the National Institute of Health. Statistically, without Zika, Colombia might expect to see 90 microcephalic births during this period.
And the country is expecting to see a spike in microcephalic births in August and September from pregnant women infected during the height of the outbreak. Researchers still don’t know whether there may be other effects on babies whose mothers had the disease.
As a result of this new “endemic” phase of the virus — where it remains persistent but at manageable levels — authorities also lifted the recommendation that women avoid getting pregnant.
The better-than-expected Zika rates in Colombia can be attributed, in part, to faulty models, Ruíz said. Initial projections were based on what researchers had seen on Yap Island, in the Federated States of Micronesia, and Brazil. Ruíz speculated that it was the varying terrain of those nations (Colombia is 100 times larger than Yap) that made them poor predictors of the virus’ spread here.
In addition, the country had just recently gone through a Chikungunya outbreak. And the measures taken in that case — including mosquito eradication — likely limited the spread of Zika, Ruíz said.
The receding tide of Zika is exactly what you would expect with this type of virus, said Aileen Marty, an infectious disease specialist at Florida International University.
“When Zika started, the entire population of the Americas, no matter where it became endemic, was immunologically naive... so that anyone who became infected had an increased chance of manifesting symptoms, because there was no natural immunity,” she said. “As the outbreak has spread and more and more people are resistant to infection they develop immunity. That’s what we see every time there’s an outbreak.”
And she predicted that the United States, and South Florida, are well prepared to handle the virus.
“We’ve had malaria, dengue and Chikungunya in South Florida... and we attack it by concentrating our efforts,” she said. “That’s why we’ll be able to manage [Zika] and hopefully, within not too long, we’ll have a vaccine.”