President Obama recently proposed a $1.8 billion emergency funding package to assist federal agencies in managing the Zika outbreak abroad and preventing it from spreading domestically. Stopping or slowing this mosquito-borne disease, which has now been reported in more than 20 Latin American countries and 20 U.S. states, would seem to be a non-partisan priority — if not for humanitarian reasons, then for unadulterated self-interest. Mosquitoes don't respect international borders and when they seek out bloodmeals they don't discriminate on the basis of party affiliation. Nevertheless, the request for Zika funding inexplicably ran into trouble almost immediately.
The Zika virus is native to Africa, as is its major mosquito vector Aedes aegypti. But Aedes aegypti, the yellow fever mosquito, has lived in the New World since European explorers inadvertently carried it here aboard ships more than 500 years ago. Today, this species thrives in at least a dozen states in the U.S., and its range is expanding. In 2013, it turned up in three counties in California.
There is no vaccine to protect against Zika and, while it's true that many who are infected remain asymptomatic, others experience rashes, joint pain and conjunctivitis; the virus has also been linked to serious birth defects if contracted during pregnancy. For the record, in addition to carrying Zika virus (and yellow fever), Aedes aegypti is an excellent vector for the viruses causing dengue and chikungunya. The global incidence of these diseases has been increasing astronomically, with millions potentially at risk. In the Americas, local transmission of both diseases has been documented in 40 countries. There is no vaccine to prevent chikungunya and the dengue vaccine is not yet 100% effective.
Obama's emergency package would provide funding to expand vector mosquito management programs, develop vaccines, educate medical professionals and vulnerable populations, and assist Zika-affected countries.
Some members of Congress are reluctant to “rubber stamp” Zika funds and suggest that money should be diverted from elsewhere, including from money allocated for Ebola response. But diseases don't take turns going global. Ebola still presents a threat and siphoning off Ebola response funds to address Zika undermines the ability to deal effectively with either disease.
It should be obvious to lawmakers that it's better — and cheaper — to manage Zika before the disease reaches crisis proportions in the U.S. Getting the genie back into the bottle is, after all, considerably more difficult than not letting it out in the first place.
Even if we develop a vaccine for Zika, that won't stop Aedes aegypti from harboring other viruses. And if we eradicate Aedes aegypti, as some have proposed, that won't stop other Aedes species from spreading Zika. Aedes albopictus, the Asian tiger mosquito, is a competent vector for yellow fever, dengue, and chikungunya and is considered a potential vector for Zika. It's been living in the Americas for 30 years and in Los Angeles at least since 2011.
Emergency funding is unarguably necessary—but not sufficient. Stable, sustained financial support for research, including entomological research spanning mosquito genomics to ecology, is essential for anticipating and circumventing the next emerging or re-emerging mosquito-borne disease. Zika is just the latest manifestation of a new world order, with ancient diseases resurging in new places and new diseases arising circumglobally.
A heroic effort launched in 1947 to eradicate Aedes aegypti entirely from the Western Hemisphere almost succeeded. By 1965, however, populations resurged, due partly to insecticide resistance, global travel and urban growth (with its accompanying proliferation of habitats preferred by this mosquito). Political complacency also deserves a share of the blame; the perceived decrease in disease risk was accompanied by decreased interest in efforts to manage the vector. All of these factors are, to varying degrees, worse today than they were 50 years ago. Congress should invest in research across the sciences, including entomology, to devise both immediate short-term and durable long-term solutions to this persistent challenge to human health.
May Berenbaum is the president of the Entomological Society of America.