More about malaria

Malaria Q & A - Do you know about malaria?

Surely, you have to be bitten many times by mosquitoes in order to contract malaria?
Apart from mosquito bites, how else might malaria spread?
Why does resistance to antimalarial drugs emerge?
What is recrudescence?
Which groups of people are at particular risk from malaria?
I’ve always prescribed prophylactic drugs for travellers to malarious areas - is there a problem with this?
Which antimalarial drugs should I consider prescribing as standby treatment?
What are the major factors affecting the choice of an antimalarial drug?

 

	Surely, you have to be bitten many times by mosquitoes in order to contract malaria?
	No, this is not the case. The disease can be contracted by just one bite from an infected mosquito

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	Apart from mosquito bites, how else might malaria spread?
	In the vast majority of cases, malaria is spread by mosquitoes. However, this blood-borne disease can also be transmitted via blood transfusion, shared hypodermic syringes and via the placenta during pregnancy.

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Why does resistance to antimalarial drugs emerge?

Drug resistance arises when genetic mutations are selected under drug pressure. The resultant resistant organisms are then transmitted from one host to the next. There are three key factors leading to the emergence of resistance: Suboptimal dosing and/or treatment duration Use of partially effective drugs Use of drugs for too long It is therefore very important to prescribe the right drug, in the correct dose for the optimal length of time if we are to maintain an effective arsenal of drugs against this dangerous disease

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What is recrudescence?

Recrudescence occurs when parasites survive in the red cells after incomplete or ineffective drug treatment, and after a brief check, continue to multiply. Recrudescence should not be confused with recurrence, which occurs during infection by Plasmodium vivax and Plasmodium ovale malarial parasites, when hypnozoites emerge from the liver months after the original infection, and reinfect the red blood cells. Recrudescence is distinguished from reinfection, which is caused by further bites from infected mosquitoes, after the original infection has been eliminated.

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Which groups of people are at particular risk from malaria?

Pregnant women - develop higher parasitaemias and more severe malaria (with maternal death) than other women. They are particularly at risk of hypoglycaemia, and fever may lead to miscarriage or premature delivery The foetus - the placenta harbours high numbers of parasites, exposing the foetus to placental insufficiency, resulting in low birth weight and increased infant mortality. Young children (less than 5 years of age) - in endemic countries, young children who have not yet built up immunity to the disease, are at greater risk than older children and adults.

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	I've always prescribed prophylactic drugs for travellers to malarious areas - is there a problem with this?
	Prophylactic drugs have a number of disadvantages. They have unwanted side effects, compliance is poor, and treatment times are long. It is becoming increasingly recognised that standby emergency treatment may be a practical alternative for some travellers.

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	Which antimalarial drugs should I consider prescribing as standby treatment?
	Assuming your patient will not be taking any other antimalarial as prophylaxis, consider: Quinine Mefloquine Malarone® Riamet® (if registered in your country for standby therapy) Note that not all drugs are approved for every country

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	What are the major factors affecting the choice of an antimalarial drug?
	Parasite type Level of drug resistance Patient's health and medical history Intended use (prophylactic, standby, acute treatment) Other factors may also influence the choice of drug in some countries, including economic considerations and availability.

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