(Bloomberg View) — In 33 years of practice, Rio de Janeiro obstetrician and gynecologist Isabella Tartari Proenca has helped countless expectant mothers through the anxieties of pregnancy and childbirth. But ever since an exotic virus called Zika hit Brazil a few months ago, she’s run out of assurances. “I get calls and text messages all day long,” Tartari told me. “My patients are terrified.”
Who could blame them? Since May, when the national health ministry confirmed the first cases of Zika virus, the mosquito-borne disease has swept the country, infecting at least half a million people. While most victims escape with a low-grade fever, skin rashes and achy joints, some dire complications have ensued. Suspected to be among them is microcephaly, a condition that leads to exceptionally small infant head size, which causes lasting neurological damage and can lead to death.
Zika has since spread across Latin America. By Dec. 22, Brazilian authorities had confirmed 2,782 cases of microcephaly this year, a fivefold increase over the yearly average since 2010; 80 babies whose mothers tested positive for Zika were stillborn or died shortly after birth.
No one knows for sure if Zika causes microcephaly, nor how the virus attacks neurological tissue. And experts can only guess at how a sleeper disease that emerged in the forests of Uganda in 1947 and was known only for scattered outbreaks in the Pacific Islands since then ended up as an urban public health emergency halfway around the globe.
Dennis Fujita and Felipe Scassi of the Institute of Tropical Medicine of Sao Paulo think the virus might have arrived with athletes or fans during the 2014 World Cup, or possibly by way of South America’s Pacific coast after an outbreak on Easter Island.
What’s certain is that Brazil’s response to the crisis came late and may already have fallen short. Consider Health Minister Marcelo Castro’s advice to families thinking about having children: “Sex is for amateurs. Pregnancy is for professionals,” he said in November. True, after the surge in microcephaly cases, President Dilma Rousseff declared a “war on the virus,” deploying police and even the armed forces to join public health workers in a door-to-door mission to preach prevention and root out the disease.
As encouraging as that sounds, the pathogens are faster. Zika is only the latest epidemic transmitted by an old scourge: Aedes aegypti, a stripe-legged mosquito that not only flourishes in the steamy tropics but is also at home in cities.
A century ago, the panic was over yellow fever. But when a vaccine was found in the 1930s and the crisis passed, so did mosquito control. That cleared the way for dengue fever, an affliction that made the jump from Asia to the Americas in the 1980s and quickly spread on the wings of Aedes aegypti. Dengue is now a pandemic, with four separate strains contaminating 390 million people a year worldwide. Last decade, Brazil accounted for 60 percent of infections, and the country has logged more than 5 million cases since 2010. After years of research, the first of several dengue vaccines under development has been cleared for marketing in Brazil, Mexico and the Philippines.
There is no vaccine for Zika and no known treatment, which leaves battling mosquitoes the only recourse. That’s a war best fought in September and October, when milder weather makes bug control manageable. By December, with temperatures spiking and mosquitoes swarming, there is little to be done.
Until a few months ago, however, health authorities were distracted by another exotic newcomer from Africa called chikungunya, but that virus petered out. No one was ready for Zika.
Underestimating a threat, then scrambling when the crisis hits: It’s a familiar script in Latin America, and exactly the sort of blind spot that emerging diseases love. “We’ve been fighting a losing battle with the mosquito for 30 years,” said virologist Mauricio Nogueira. By the time the authorities were paying attention, Zika had become an epidemic. Throw in underfunded hospitals and faulty primary care, and a full-blown public health crisis was born.