By Erik McLaughlin, M.D.
What is malaria? It’s a parasitic infection of the red blood cells and liver that is acquired from the bite of an infected mosquito. Main symptoms include fatigue, muscle aches and a fever. Fever is known to undulate (come and go) approximately every three days. There are four main types: Plasmodium Vivax, Plasmodium Ovale, Plasmodium Malariae, and Plasmodium Falciparum.
Most every tropical area of the world. P. Ovale is localized to West Africa only. All other types are found worldwide.
Transmitted by bite of infected Anopheles mosquito. Incubation period of 9-20 days, or longer.
Avoiding outdoors at dawn and dusk (mosquito feeding times), long clothing to cover arms and legs, bed nets, premethrin treated clothing, DEET body spray, destroying mosquito breeding areas and anti-malaria medications.
Blood smear that demonstrates Plasmodium species, try to draw blood during fevers.
Based on species and sensitivity to medication. Chloroquine sensitive infections can be treated with quinine (600mg base initially then 300mg base at 6, 24 and 48 hours later) with doxycycline for 7 days. Mefloquine (15mg/kg one time) is used for chloroquine resistant species. Multi-drug resistant strains can require artesunate.
Different types of malaria can be found in different parts of the world and sometimes you can find more than one type in the same place! Malaria causes a special type of fever that “comes and goes”. This fever generally comes on about every 3-7 days, lasts about 12 hours then disappears. More about why this happens in a bit. The length of time between the fevers can sometimes tell you what species of malaria you have been infected with. I always advise anybody traveling to an area known to have malaria to speak with a doctor specializing in travel and tropical medicine.
There are 4 main types of malaria
Plasmodium Vivax (can lay dormant in liver)
Plasmodium Ovale (can lay dormant in liver, uncommon outside West Africa)
Plasmodium Malariae (low level infection possible for years)
Plasmodium Falciparum (the worst type, drug resistant)
How do you get Malaria?
Humans get malaria by being bitten by a mosquito that is carrying malaria. The female mosquito carries malaria but does not get sick, herself. She gets the malaria by biting another human or mammals (monkeys) that already have malaria. It is a vicious cycle.
Then what happens?
Once infected with malaria, from the mosquito bite, the parasites travel to the liver. There, they begin to grow and mature within the cells of the liver. After a few days to months later, the parasites are ready to leave the liver. As they leave, they literally rupture the cells of liver breaking out. From the liver, the parasites migrate to the red blood cells (RBC). Once the parasites get into the red blood cells, they grow and mature some more. Then, you guessed it, once they have grown up some more, they rupture out of the red blood cell (RBC). This causes the fever to appear to “come and go.” As the parasites are growing in the red blood cells, there is no fever. Once they mature, they all rupture out of the RBCs together at the same time, causing a fever. Once they leave the RBC, the parasites infect other red blood cells. The cycle starts over again and the fever goes away. Once the new parasites mature in the red blood cells (after about 3-7 days), they rupture out and cause a fever. This goes on and on, over and over until treatment or death.
I don’t want it! What do I do?
Anti-malaria pills are the last way to stop this infection. These pills/medication are made to be taken by the traveler who is going to an area known to have malaria, for the entire duration of their trip and a few weeks after they return. There are many, many types of medications to chose from. To determine if you need to take anti-malaria pills, do some research. Visit the WHO website and see what the most current advice is for the area you are going to. Their web-site is very up-to-date.
A few basics about malaria prophylaxis (prophylaxis means doing something to avoid getting sick) should begin with the type of malaria you might encounter. Chloroquine is the first drug you should know about. This is an older drug that is used for treatment and prophylaxis of malaria, today. However, not all forms of malaria can be prevented or treated with this older drug. This type of malaria is Plasmodium Falciparum. P. Falciparum is mostly resistant to chloroquine. Malaria is divided into two types, chloroquine sensitive (chloroquine can kill these types) and chloroquine resistant (chloroquine does not kill these types). Plasmodium Falciparum is generally known to be resistant to chloroquine and you need to choose another type of medicine to protect yourself. Don’t worry, there are several out there.
So, the first thing to do is check the websites mentioned and see what type of malaria is found in the area you are going to. Do they have Plasmodium Falciparum? Is the malaria there sensitive or resistant to chloroquine? If the area is know to not have P. Falciparum and the malaria there is sensitive to chloroquine. chloroquine is your drug and should protect you. If the area has Falciparum or is resistant to chloroquine, look for another of the newer drugs to use. Some of these drugs for chloroquine resistant malaria include mefloquine, proguanil and doxycycline (yes, the antibiotic). Most of these drugs are also used to treat malaria, once somebody has become infected.
** Doxycycline, a very common anti-malarial, will interfere with birth control pills and increase risk for sunburn
The anti-malaria medicine should be started a month before the trip. I advise a month because there may be some side-effects to the medicine. You would rather know about them at home, where you can change to another medicine before your trip begins, rather than have to choose between the side effects or the risk of malaria. Regardless, you should generally be taking the same prophylaxis medication for 2 weeks before you have a chance of getting malaria. The drug needs time to build up in your body. Further, it is important to take the medicine a few weeks after you come home. You could have been bitten and infected as you got on the airplane to fly home. If you just suddenly stop the moment you get home, that parasite hiding in your liver could still be a problem! There are some medicines, such as Doxycycline, that can be taken after you return from the trip to ensure that there are no parasites hiding in your liver.
Some different types of anti-malaria prophylaxis are taken everyday and some are taken once per week. Pick a medicine that is not going to be a problem to take. If you frequently forget to take medicine, consider one that doesn’t need to be taken daily. Cost is another consideration. The point is that if you don’t follow the instructions, you are at a greater risk for getting malaria. Nobody wants that. If you have any prior medical conditions such as pregnancy, are immunocompromised or have other health concerns, speak with your travel medicine specialist well in advance of your trip.
* Sickle Cell Trait (curved or sickled red blood cells) is believed to protect affected African-Americans from severe Plasmodium Falciparum infections.
* Most Indigenous Africans have a natural resistance to Plasmodium Vivax due to am absence of Duffy Factor on their red blood cell surfaces.
* The word “malaria” come from the two words “mal” and “aria” meaning bad air. This was because people first believed the disease was caused by bad air in the area. We know now that is it mosquitoes that transmit the disease.
It is important to realize that these assumed protections do not work in all individual cases and proper protection should be discussed with a doctor and used as instructed to prevent acquiring malaria.
The type of mosquito to watch out for is named Anopheles. This is the name of the whole species, in fact. These females like to bite at night. In fact, they do most of their biting at dawn (sun rising) and dusk (sun setting). With this in mind, we know how to begin to avoid them. Not being outside during these times helps us avoid being bitten. Wearing long pants and long sleeved shirts help keep them from finding our tasty skin. Further, soaking or spraying your pants and shirts with a special spray called Premethrin helps keep them away, even more. Bug repellent works great and needs to be used. DEET is the name to know. Make sure that your bug repellent contains 20-30% of this solution. Less than this and it might not work and anymore than 30-35% will irritate your skin. For kids less than 8-10 years old, do not use anything stronger than 10% DEET. Burning “mosquito coils”, citronella candles or “mosquito tablets” really make the Anopheles want to stay away, too. Make sure to do this. Mosquito nets over your beds also work well, if you are in an area with open windows or doors. A climate-controlled hotel will not have a way for the mosquitoes to get in.
Lastly, people who live in the areas where these mosquitoes are found need to help reduce breeding grounds for these mosquitoes. The mosquitoes breed and lay their eggs in standing water. This can be still lakes and ponds, flower pots that collect water, old tires that can collect water and virtually anything that can hold water. May sure to tip these pots and containers over so they don’t collect water and allow the eggs to be laid.
If the water cannot be dumped out or the container turned over, like a pond, there are chemical larvacides (these kill the larva or baby mosquitoes) that can be put into the water. Fish also work well and are a bit more environmentally responsible. The fish eat the mosquito larvae before they hatch.
Malaria is just one of many good reasons to make sure you get backpacking travel insurance before you go!
About the Author:
Erik McLaughlin, M.D. lives in Chicao and is dedicated to helping travelers around the world stay healthy. He writes for Gadling, Matador, and runs the website http://adventurehealthclinic.com.