The White House's new $1.8 billion plan to fight the Zika virus, explained

The Zika virus hasn't (yet) done very much harm in the United States. But it's already freaking people out — and the Obama administration is now calling for a sweeping response before it spreads any further.

On Monday, the White House announced it would ask Congress for $1.8 billion to combat the mosquito-borne Zika virus, which has already infected more than 1 million people in South America and is thought, in some cases, to damage the brains of fetuses.

What makes Zika so unnerving is that it's relatively new — it was virtually unknown in the Western Hemisphere until arriving in Brazil in 2014, likely during the World Cup. Since then, it has spread rapidly throughout South and Central America and the Caribbean, carried by the notoriously pesky Aedes aegypti mosquitoes. So far, only about a dozen people in the United States have been infected, mostly travelers from abroad. But the virus is expected to arrive in Florida, Texas, and other Southern states during the spring and summer mosquito season.

For most people, Zika isn't very dangerous at all. Only about 20 percent of people show any symptoms, and those usually involve a low-grade fever, sore body, headache, and sometimes a rash.

But the reason the disease has gotten so much attention is the newly discovered possibility that it may cause birth defects. Over the past year, Brazil has seen a sharp rise in reported cases of microcephaly — a birth defect characterized by a shrunken head and incomplete brain development. At least six cases appear to have a link to Zika, and scientists are still sorting through thousands of other cases to see if there's actually a connection. Many Latin American countries aren't taking the chance, however, and are warning women to postpone pregnancy for a year or two.

Why the White House wants $1.8 billion to fight Zika

Stopping the Zika virus won't be easy — experts say it will basically require a bunch of disparate tactics.

First, more research. Scientists still need to better understand the virus, to get a handle on how exactly it spreads. We know that mosquitoes are the main carriers of Zika, but it also appears the virus can spread through sexual transmission. We also need better ways of testing for the disease (especially among those who don't show symptoms). And experts still need to understand the link between Zika and microcephaly, or between Zika and Guillain-Barré syndrome, a neurological disorder that can temporarily paralyze people.

Second, prevention. This will involve tracking the disease, something the Centers for Disease Control and Prevention (CDC) does for other outbreaks. It will also mean controlling Aedes aegypti mosquitoes, which thrive in urban areas and can breed in virtually any small pool of water. Eradication programs are difficult and time-consuming — using larvicides, getting rid of any potential breeding sites such as trash or old tires. And scientists need to know if and when other mosquitoes, like the Aedes albopictus, start carrying Zika.

Fortunately, prevention will be easier in the United States than it is in Latin America, in part because the Aedes aegypti mosquito has a smaller range (mainly in the South), but in part because we have established mosquito control programs and the widespread use of air conditioning allows people to keep their windows closed and avoid bites.

Finally, since none of these prevention strategies work perfectly, it would be nice to eventually have a vaccine for Zika — which is still years away.

To that end, the White House is asking for $828 million for the CDC to increase research into Zika, monitor the disease, and improve testing programs. It's also asking for $250 million to expand health programs in Puerto Rico, where the virus has already taken hold. It's asking for another $200 million for vaccine research, and $335 million to the US Agency for International Development to support Zika control efforts abroad.

On top of that, the White House is asking for $210 million to establish a new Urgent and Emerging Threat Fund that would build readiness in case other mosquito populations — like the Aedes albopictus — start carrying Zika to new states.

How the Zika funding compares with funding for other diseases

In 2014, the White House asked Congress for $6.2 billion to fight the ongoing Ebola outbreak, which was mainly ravaging Liberia, Sierra Leone, and Guinea but had recently entered the United States and was causing mass panic in the media. Congress eventually approved $5.4 billion.

Ebola was much, much deadlier than Zika, but it was also easier to stop (since it was spread by fluid contact between humans, which is more straightforward to prevent than mosquito bites). Ultimately, only two people ever contracted Ebola inside the United States. And the disease has since been mostly stopped in West Africa, though not before killing more than 11,000 people.

That same year, the White House asked for $13.9 billion in funding to combat HIV/AIDS, which still kills more than 1 million people around the world (including many Americans).

That goes to show two things. There's not always a tight link between how deadly a disease is and how much funding Congress approves. Newer diseases dominating the headlines can command a disproportionate share of funds. But the Ebola case also shows that a very rapid influx of money really can do quite a bit to halt a disease that's causing mass panic.

Further reading:

• You can read the White House's.
• on the Zika virus
• The about how to kill off mosquitoes and stop the Zika virus