The threat of contracting Zika virus has been looming over Americans who travel to Latin America or the Caribbean for quite a while now. But fear spiked when a case in Miami was recently confirmed as contracted from a local mosquito.
And now we are all on alert for Aedes aegypti mosquitoes, the type that carry and transmit Zika virus, looking for the best-performing chemical repellents and home remedies.
Most recently, videos have been circulating on social media that boast the amazing and near magical power of coffee and its effect on Zika-carrying mosquitoes. But is all this hype true? Could the solution really be that simple?
How coffee kills mosquitoes
In 2003, a study showed that used coffee grounds and caffeine could kill off the larvae of Aedes aegypti by blocking their development from becoming adult mosquitoes. The insects also couldn’t develop a resistance to the coffee.
Later, in 2007, a team of researchers discovered the same effect on larvae when using coffee grounds and a liquid infused with coffee, both at low concentrations. This research suggested that coffee could be used to prevent mosquito populations from growing in gardens and even urban areas, the Huffington Post reports.
Again in 2012, coffee extracts were used to prevent development of larvae and kill off both Aedes aegypti and Aedes albopictus mosquito populations—using both caffeinated and decaffeinated versions.
What’s more, a 2015 study revealed that mosquitoes are deterred from laying eggs in coffee-treated water due to its darker color. And if they do, as proven before, the larvae die.
But there’s a major catch
This seemingly quick fix has a huge drawback: To actually control the entire mosquito population, coffee would have to be added to every still water source, which is where the flies congregate and reproduce.
And there is obviously no way to treat every single stagnant water source that exists. Additionally, all of this research does not directly address merely sprinkling your garden with grounds, as the popular Facebook post advises.
So what can you do?
So you’ve got a bunch of spent coffee grounds and undying fear of contracting Zika. Here’s what you can do about both: AARP suggests letting the grounds dry and age for about a month in an open container, then sprinkling them into puddles and other standing water to kill the larva; in addition, the site says you can spray leftover brewed coffee on weeds and outdoor surfaces because “mosquitos hate its aroma.”
And apparently covering your yard with spent grounds might be a good idea after all: The National Center for Biotechnology Information at the U.S. National Library of Medicine supports the claim that female mosquitoes lay fewer eggs on areas covered by coffee grounds, saying “coffee and its waste may be useful in developing potent, low-cost, and bio-rational mosquito control strategies.”
So in the end, it’s worth a shot if you have grounds you’d otherwise be tossing in the trash. Because you’ve really got nothing to lose.
Rheanna O’Neil Bellomo
