~Written by Theresa Majeski (Contact: theresa.majeski@gmail.com)
Malaria has been described in literature dating 4,000 years ago but has probably been around longer and has certainly had an influence on the history of humanity. Even though malaria has been around for thousands of years we haven’t done a very good job of eradication. Yes, we have eliminated malaria from some parts of the world, notably most of the northern hemisphere, but malaria still killed an estimated 584,000 people in 2013.
So why haven’t we been able to eradicate malaria from the tropical regions of the world? It can’t be just due to the mosquitos because mosquitos that can carry malaria are found lots of places in the world.
Figure 1 Geographical location of mosquito species capable of carrying malaria, Courtesy of the CDC
According to Sonia Shah in this superb TED talk, there are four reasons malaria still exists:
1. Scientific challenges – malaria is an incredibly complex parasite that undergoes multiple changes in humans and mosquitos so it’s hard to develop new drugs against it
2. Economic challenges – malaria is found in lower income areas of the world and malarial episodes make it hard for people to continue with their daily lives and work which contributes to the lower income status of these areas
3. Cultural challenges – people living in malarial areas don’t view malaria as we in the West do, they view it as a part of life just like we view the deadly influenza virus as a part of life
4. Political challenges – eliminating or eradicating a disease takes a large concerted effort with involvement and resources from governments and some malarious countries just don’t have the drive to eliminate malaria
Even though it seems like malaria eradication from the world is an unachievable goal, work is being done to decrease the burden of malaria in affected countries. One way we’re fighting malaria is with the use of bed nets, which persons sleep under every night to prevent them from being bitten by malaria carrying mosquitos that feed during the night. However there are drawbacks to bed nets. You may have also seen the recent article in the New York Times featuring an interview with a fisherman who is using his bed net to catch fish so his family doesn’t starve. A second way we’ve been fighting malaria is with indoor residual spraying. This is where workers spray down the indoor walls of houses with insecticide to prevent the mosquitos from coming into the house. Another method in the fight against malaria may be a little less known, and that is with biological methods. Biological methods are things like using fungi or bacteria to control mosquito populations, or using fish to eat the mosquito larvae.
While every method has its drawbacks, researchers are still trying to find new methods to help control malaria. One method caused a small media storm a couple weeks ago, the use of genetically modified mosquitos. Controversial sounding isn’t it? Basically, researchers give male mosquitos a gene preventing their offspring from surviving. So the males mate with the females (who are the only ones who bite to get blood to make baby mosquitos) and those offspring die, as do the original male and female once they’ve lived out their lifespans. But as with all things involving any sort of genetic engineering, people are hesitant. Work is still continuing on for a vaccine for malaria with hope for licensure of at least one vaccine in 2015. There’s also a TED talk (can you tell I love TED talks?) by Bart Knols that demonstrates a pill people take which results in the death of mosquitos who bite them. Bart Knols also discusses using dogs and their powerful sense of smell to help workers find mosquito larval breeding groups so those breeding grounds can be treated with insecticide. It can be hard to find all of the mosquito breeding grounds during the rainy seasons as every little indent in the ground can fill with water and provide an excellent breeding ground for mosquitos.
While malaria continues to cause high numbers of death and a high disease burden, researchers are continuing to get creative with methods of controlling malaria in the hopes of one day eradicating it. That goal may be a ways off yet, but at least one researcher thinks we may one day be shooting mosquitos out of the sky with lasers.