One year into the Zika outbreak: how an obscure disease became a global health emergency

Ill-prepared to cope

The emergence of Zika in the Americas surprised a world that was ill-prepared to cope, especially with the heart-breaking neurological abnormalities in newborns. With no vaccines, clinicians can offer women of child-bearing age little protection beyond advice to avoid mosquito bites, delay pregnancy, or refrain from travel to areas with ongoing transmission.

Concerned pregnant women also get little reassurance. Apart from impeding disease investigations, the lack of reliable and widely available diagnostic tests means that pregnant women possibly exposed to Zika are left to worry about the consequences for their unborn babies, especially since ultrasound can detect brain abnormalities only in the third trimester of pregnancy.

The fact that sexual transmission of Zika is more common than previously thought further complicates advice to couples planning their families. During the first year of the outbreak, sexual transmission was documented in nine countries: Argentina, Canada, Chile, France, Italy, New Zealand, Peru, Portugal, and the United States of America.

Few countries in the outbreak zone offer universal access to sexual and family planning services. According to a recent study, countries in Latin America and the Caribbean have the highest proportion, at 56%, of unintended pregnancies anywhere in the world.

In Brazil, many women giving birth to babies with microcephaly are young and poor. In a rich country, like the US, the costs of caring for a single child with microcephaly have been estimated to be as high as $10 million. In a poor country, the burden of care will largely fall on mothers, who may have to give up salaried work or have difficulty finding the time and the transportation to access support from health and social services.

The burden of Zika falls on the poor for other reasons as well. In tropical cities throughout the developing world, the poor cannot afford air-conditioning, window screens, or even insect repellents. With no piped water and poor sanitation, they are forced to store water in containers, providing ideal conditions for the proliferation of mosquitoes.

Perhaps the greatest failure of coping capacity comes from the complacency that set in after the spectacularly successful mosquito control campaigns in the 1940s and 1950s. During the 1960s, with yellow fever vanquished, funding for mosquito control dried up, control programmes were largely dismantled, and entomologists vanished. The response to the infectious disease threat shifted from building basic public health infrastructures and capacities for prevention as the first line of defence to the use of surveillance to pick up early signals of an outbreak and then mount an emergency response.

The weaknesses of such a stop-gap approach have been demonstrated by the dramatic resurgence of dengue, the recent emergence of chikungunya as a significant threat to health, the delayed detection and subsequent exponential spread of Ebola in West Africa, and this year’s return of urban yellow fever to Africa. Zika seems destined to make these weaknesses even more explicit.