Malaria in Kitwe Zambia

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QUESTION

Is it dangerous for my children two years old in Kitwe?

ANSWER

Kitwe has been part of the Roll Back Malaria campaign to control malaria in Zambia—the program has been very successful, reducing deaths by malaria by over 65% nationwide. However, there still is a risk of contracting malaria in most parts of the country, and so preventative measures should be taken when visiting or living in Kitwe, such as sleeping under a long-lasting insecticide treated bednet, wearing long-sleeved clothing in the evening and at night and screening doors and windows to prevent mosquitoes from entering.

Anopheles Mosquito

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QUESTION

What does Anopheles looks like?

ANSWER

Mosquitoes of the genus Anopheles are responsible for all transmission of malaria in mammals, including to humans. They are night-feeding mosquitoes, usually biting between dusk and dawn, though they may also be active during the day in heavily shaded environments.

Like all mosquitoes, Anopheles are usually found either as freshwater larvae, which prefer stagnant, still water, or flying adults, of which only the females feed on blood (the males exclusively feed on nectar).  Anopheles larvae lie parallel to the surface of the water where they live (in contrast to Aedes and Culex larvae which hang at an angle), whereas the adults rest with their bodies at a 45 degree angle upwards (again in contrast to Aedes and Culex adults, which rest parallel to their resting surface).

Anopheles Mosquito

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QUESTION

Why is it only the female anopheles mosquito alone can cause malaria but not the male anopheles mosquito or any other mosquitoes?

ANSWER

Malaria is actually caused by a single-celled parasite called Plasmodium—it is transmitted via the bite of a female mosquito, of the genus Anopheles, as she takes a blood meal from a human (or other mammal) host. Male mosquitoes do not feed on blood (they only feed on nectar), whereas females need the nutrients from blood in order to produce their eggs; as such, only female Anopheles transmit mosquito.

Why only Anopheles are able to transmit malaria to humans is interesting—birds and reptiles also can get Plasmodium (though different species than those that infect humans and other mammals), and these kinds of malaria can also be transmitted by other kinds of mosquitoes, such as Aedes and Culex. Other closely related blood parasites can even be transmitted by other flying insects, such as sand flies and black flies. However, it is true that only Anopheles can transmit human malaria.

How to Prevent Malaria

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QUESTION

How to prevent malaria?

ANSWER

There are a number of ways to prevent malaria. These can be placed into two categories: medication and vector protection.

For medication, there are drugs you can take to prevent the malaria parasite from developing after someone is bitten by an infected mosquito. These drugs are known as “chemoprophylaxis.”

There are several different kinds, such as doxycycline, mefloquine (marketed as Lariam), atovaquone-proguanil (marketed as Malarone) and chloroquine—the type you use depends on the type of malaria present in the area. For example, in much of Africa and India, malaria is resistant to chloroquine, so this cannot be used as a prophylactic. In parts of Thailand, resistance to mefloquine has emerged. However, if the appropriate type of prophylaxis is used, it is very effective against malaria.

The problem is that these drugs have not been tested for long-term use, can be expensive and may have side-effects. Therefore they are of limited use for people who live in areas where malaria is endemic, and are more appropriate for travelers who are in malarial areas for short amounts of time. However, anti-malarial medication may be used in a very specific way for people at particularly high-risk for malaria, such as pregnant women and young children. In these cases, the high-risk individuals receive a dose or series of doses of malaria medication in order to prevent malaria. This form of prevention is known as intermittent preventive therapy (IPT).

Vector prevention involves protecting oneself against getting bitten by mosquitoes. This can involve wearing long-sleeved clothing in the evenings and at night, when malaria mosquitoes are most active, or wearing insect repellent on exposed skin. Indoor residual spraying, whereby repellent and insecticides are sprayed inside the house, can also be used to bring down the number of mosquitoes.

Another very effective technique for preventing malaria is to sleep under a long-lasting insecticide-treated bednet. The mesh acts as a barrier against the mosquitoes, and the insecticide impregnated in the mesh further repels the mosquitoes and prevents them from biting through the mesh.

What year was the cause of malaria discovered?

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QUESTION

When did they find out that a bug bite caused malaria, and what year was that?

ANSWER

In 1880, Charles Louis Alphonse Laveran observed that malaria was caused by a parasite in the blood; it wasn’t until 1897-1898 that Ronald Ross, a British Army medical doctor, discovered that the parasite could be transmitted between hosts (he used birds for his experiments) by mosquitoes.

Mefloquine

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QUESTION

My son, 7 years old, took Mefloquine course for malaria prevention last year. We are travelling to INdia again this year. Does he and myself need to repeat the anti-malaria pills again this year?

ANSWER

Yes. You need to take anti-malarial preventative medication every time you go back to a malarial area. It is also important to continue taking the drug for the required amount of time before and after returning from your trip—in the case of mefloquine, you need to start taking it two weeks before you depart for the malarial area, and then continue you taking it for 4 weeks after you get back. This ensures that if you are exposed to malaria at the beginning or end of your trip, you are still adequately protected.

If you have some time, we at Malaria.com would be very grateful if you would take a minute or two to answer our malaria survey that we are conducting about our readers’ experiences with anti-malarials, and particularly their side effects.

P.vivax Malaria Treatment

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QUESTION

Which drug should be given to a p.vivax malaria patient with deficient glucose 6-phosphate for prevention of relapse?

ANSWER

Unfortunately, primaquine is the only drug that is known to kill the latent liver stages of P. vivax and P. ovale. Since it can induce haemolysis in people with G6DP deficiency, this drug is usually not recommended for people with this deficiency. However, there are actually gradations of severity of G6DP deficiency, and so in some cases, primaquine at therapeutic doses may be tolerated by people with only mild G6DP deficiency, if they are carefully monitored for anaemia throughout the process. This may be preferable to no treatment, since no other known medication can prevent relapse.

Is Malaria Contagious?

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QUESTION

Is malaria contagious?

ANSWER

Malaria cannot be transmitted directly between people via normal circumstances, so it is not contagious in the same way flu or the common cold is contagious. It also cannot be sexually transmitted.

In most cases, malaria can only be transmitted via the bite of an infected mosquito, so unless those mosquitoes are present, it cannot be transmitted. Because infectious stages of the parasite are present in the blood, in some cases malaria can be transmitted via blood transfusion (if the blood is not properly treated or screened), via organ transfer, or from a mother to her foetus, either via the placenta or during childbirth (this is called “congenital malaria”). However, compared to the amount of transmission which occurs via mosquito, these cases are relatively rare, and the vast majority of the time, malaria is not directly transmitted between people.

Recurrent Malaria

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QUESTION

can malaria represent itself after 50 years?

ANSWER

There are two types of malaria which can lay dormant for long periods of time, though I don’t personally know of more than a handful of cases where the relapse was a matter of decades after the initial infection. These two types are P. vivax and P. ovale, so if you know you were infected with one of these types a number of years ago, it is possible that you could experience a relapse many years later, though as mentioned above, it is rare for the time lapse to be as long as 50 years.

Malaria Treatments

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QUESTION

What are the of different types of antimalaria drugs?

ANSWER

Most drugs used in treatment are active against the parasite forms in the blood (the form that causes disease) and include:

  • chloroquine
  • atovaquone-proguanil (Malarone®)
  • artemether-lumefantrine (Coartem®)
  • artesunate-pyronaridine (Pyramax®)
  • dihydroartemisinin-piperaquine (Duo-Cotecxin®)
  • mefloquine (Lariam®)
  • quinine (given intravenously, this is recommended first-line treatment for severe, complicated malaria)
  • quinidine
  • doxycycline (used in combination with quinine)
  • clindamycin (used in combination with quinine)

All of the treatments above which combine an artemisinin-derivative (such as artemether, artesunate or dihydroartemisinin) in combination with another anti-malarial are called the artemisinin-based combination therapies (ACTs) and are collectively recommended by the World Health Organisation as the first line medication against uncomplicated malaria.

In addition, primaquine is active against the dormant parasite liver forms (hypnozoites) and prevents relapses. Primaquine should not be taken by pregnant women or by people who are deficient in G6PD (glucose-6-phosphate dehydrogenase). Patients should not take primaquine until a screening test has excluded G6PD deficiency.