How Much Time Between Mosquito Bite and Malaria Symptoms?

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QUESTION

If a mosquito carrying malaria is biting you, do you get sick the next day?

ANSWER

No.  There is a delay called the incubation period, which usually is between 7 to 30 days (depending on the malarial parasite the anopheles mosquito is carrying). The shorter periods are observed most frequently  from P. falciparum and the longer ones with P. malariae.

Antimalarial drugs taken for prophylaxis by travelers can delay the appearance of malaria symptoms by weeks or months, long after the traveler has left the malaria-endemic area. (This can happen particularly with P. vivax and P. ovale, both of which can produce dormant liver stage parasites; the liver stages may reactivate and cause disease months after the infective mosquito bite.)

Such long delays between exposure and development of symptoms can result in misdiagnosis or delayed diagnosis because of reduced clinical suspicion by the health-care provider. Returned travelers should always remind their health-care providers of any travel in malaria-risk areas during the past 12 months.

How Long Does it Take to Feel Ill from Malaria?

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QUESTION

How soon does a person usually to feel ill after malaria infection?

ANSWER

After being bitten by an infected mosquito, there is an “incubation period” before the person begins to suffer from symptoms of malaria. This time corresponds to the period the malaria parasite spends in the liver; it is once it enters the blood and begins to destroy red blood cells that initiate the onset of symptoms. The length of the incubation depends on a number of factors, including the type of malaria and whether the person has been taking anti-malarial preventative medication (prophylaxis), but the usual length of time is between 1-4 weeks.

Causes of Malaria

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QUESTION

What are the causes of malaria?

ANSWER

Malaria is caused by a parasite called Plasmodium, which is transmitted via the bites of infected mosquitoes. In the human body, the parasites multiply in the liver, and then infect red blood cells. Usually, people get malaria by being bitten by an infective female Anopheles mosquito.

Only Anopheles mosquitoes can transmit malaria and they must have been infected through a previous blood meal taken on an infected person. When a mosquito bites an infected person, a small amount of blood is taken in which contains microscopic malaria parasites. About 1 week later, when the mosquito takes its next blood meal, these parasites mix with the mosquito’s saliva and are injected into the person being bitten.

Following the infective bite by the Anopheles mosquito, a period of time (the “incubation period”) goes by before the first symptoms appear. The incubation period in most cases varies from 7 to 30 days. The shorter periods are observed most frequently with P. falciparum and the longer ones with P. malariae.

Because the malaria parasite is found in red blood cells of an infected person, malaria can also be transmitted through blood transfusion, organ transplant, or the shared use of needles or syringes contaminated with blood. Malaria may also be transmitted from a mother to her unborn infant before or during delivery (“congenital” malaria).


Is it just a cold?

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QUESTION

I came back from a Kenya safari and Mombasa beach holiday 21 days ago.
I took my malaria tablets as prescribed, and only got 5 bites on my last morning.

Since yesterday, I have been feeling hot then cold, though not shivering or overly sweating. A headache which is constantly there. I have also today been sick after eating/drinking. Feeling really tired. Also sore throat and blocked nose which makes me think its more a cold, so don’t want to bother my GP.
Any advice would be appreciated.

ANSWER

Malaria does have an incubation period, which means that the symptoms only show up days or weeks (or in some cases, years) after the patient is bitten by an infected mosquito. Different species of malaria have different incubation times; Plasmodium falciparum, which is the most common form in sub-Saharan Africa, usually has shorter incubation times than P. vivax, a still-acute but less deadly form. P. falciparum incubation is usually between 1 and 3 weeks, although taking anti-malarial medication can extend it. As such, since you began experiencing symptoms within a few weeks of returning, there is definitely a chance it could be malaria, although less likely if you haven’t experienced any fever (this is a key symptom of malaria, and usually goes in cycles of about 48 hours). However, since malaria is a serious issue, and can progress rapidly if not treated, I would suggest you see your GP – if you tell them that you have recently returned from a highly malarial area, they will understand your concern! Alternatively, if you live near London, if you have a fever you can go straight to the A&E department of the Hospital for Tropical Diseases (HTD) in Warren Street, where they have doctors that specialise in traveller’s health and tropical medicine.