Malaria Infection

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QUESTION

How can you get infected with malaria?

ANSWER

Malaria is transmitted directly via the bite of an infected mosquito. Only certain female mosquitoes, of the genus Anopheles, can carry malaria. The mosquito picks up the malaria parasite (there are five different types of malaria that infect humans, though all are transmitted in exactly the same way) when it feeds on the blood of an infected person. The parasite then undergoes a cycle of reproduction in the mosquito, before new parasites migrate once again to the mosquitoes salivary glands. From here, they are able to escape into the blood of a new human host when the mosquito takes another blood meal by biting the person.

Since malaria is transmitted by blood, there have been a some reports of malaria transmission via organ donor or blood transfusion, though most countries now screen for malaria before using donated blood or organs. Additionally, if a pregnant woman gets malaria, the parasite can be passed to her baby either across the placenta or during delivery; this is called “congenital malaria”, and can be quite harmful to the baby. As such, and also because pregnant women themselves are especially vulnerable to malaria, many campaigns have dedicated themselves to providing pregnant women with long-lasting insecticide treated bednets and other measures to prevent and treat malaria.

Malaria in Australia and Bali

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QUESTION

Is Australia, Bali or Tasmania in the malaria affected area?

ANSWER

While malaria used to be endemic in parts of Australia (not Tasmania—it is too cold), the country was declared to be free of malaria transmission in 1981. However, several hundred cases are reported in Australia every year, mainly brought back by travellers returning from other regions, such as south-east Asia and Africa.

The tropical northern region of Australia, i.e. Northern Queensland and particularly the Torres Strait area, is climatically very suitable for malaria transmission, and some local outbreaks may occur. Similarly, Bali is climatically very suitable for malaria, and some transmission does occur, though not high levels. For both Bali and northern Australia, it is not usually considered necessary to take anti-malarial medication while visiting the region, but precautions should be taken against getting mosquito bites, as this is how malaria is transmitted. Such precautions include sleeping under an insecticide-treated bednet, wearing long-sleeved clothing in the evenings and at night, and wearing insect repellent on exposed skin.

First Cases of Malaria

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QUESTION

When was malaria first detected?

ANSWER

Humans have known about malaria as a disease for thousands of years. The earliest written record of malaria is from ancient China, 2700 BCE. The ancient Romans and Greeks also described the symptoms of malaria, though none of these ancient people knew the true cause or had identified specifically how it was transmitted. This was first achieved in the 19th century, first in 1880 by Charles Louis Alphonse Laveran, who observed the parasites that cause malaria in the blood of a patient. A few years later, in 1897/1898, Ronald Ross discovered that the parasites were transmitted between hosts via mosquitoes, thus laying the foundations for future decades of malaria control efforts.

Malaria Outbreaks

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QUESTION

What is the largest outbreak in the world from malaria?

ANSWER

Most parts of the world don’t suffer from malaria “outbreaks” in the traditional sense of the world. Instead, malaria is “endemic,” which means that transmission is on-going all of the time. In some cases, transmission is seasonal, but each year’s level of disease incidence is similar to the next year’s. Having said this, despite no major and obvious “outbreaks” malaria has probably killed more people in history than any other disease.

Outbreaks of malaria do occur in places where malaria is not usually found, though these are usually small and isolated. For example, while Jamaica was previously malaria free, an outbreak in 2006/2007 resulted in 370 cases. By the end of 2007, it had been declared malaria-free once more, as transmission was interrupted. In 2002, a man with Plasmodium vivax caused an outbreak among 10 fellow campers at a camp site in Northern Queensland, Australia. In the US in 2008, almost a thousand cases of malaria were reported, though most of those were imported cases from travellers who had recently returned from malaria endemic areas, and therefore did not get infected within the US.

Causes of Malaria

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QUESTION

What is malaria usually caused by?

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.

If you have ever taken anti-malaria medication, please take this brief Malaria Survey.

How Does One Contract Malaria?

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QUESTION

How to get 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.

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).

If you have taken medications for malaria, please help Malaria.com by taking our Malaria Medication Side-effects Survey: Treatment and Prophylaxis. Thank you!

Malaria Transmission Through Sexual Contact

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QUESTION

Can i get malaria if i have sex with someone that has malaria?

ANSWER

No. Malaria cannot be sexually transmitted. In virtually all cases, malaria is transmitted through the bite of an infected mosquito, of the genus Anopheles. The mosquito passes the malaria parasite (there are several species which cause malaria in humans, all of the genus Plasmodium) through its saliva when it feeds on blood. Only female mosquitoes feed on blood, and so only females transmit malaria. The mosquito picks up malaria also by feeding on blood, this time from someone who already has the infection.

The only other ways to get infected with malaria are through blood transfusion, organ transplant and via the placenta during pregnancy (“congenital” malaria), and these are all very rare, particularly as blood and organ donors are now usually screened for malaria infection prior to transfusion or transplant.

If you have taken medications for malaria, please help Malaria.com by taking our Malaria Medication Side-effects Survey: Treatment and Prophylaxis. Thank you!

Community Control of Malaria

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QUESTION

how can the community can control malaria through personal protection?

ANSWER

That’s a very good question. One of the most effective known ways for reducing infection with malaria is through the use of long-lastong insecticide treated bednets. Sleeping underneath one at night drastically reduces the chance of being bitten by the Anopheles mosquitoes that transmit malaria.

Other personal protection measures include indoor residual spraying (IRS) with insecticides, which reduces the number of mosquitoes inside houses and also prevents infection. These protection methods protect individuals and families from malaria, but they also can assist in interrupting transmission—that is, if enough families use bednets and do IRS, the whole community may benefit from reduced numbers of mosquitoes that are carrying malaria.

Estimates of the level of bednet or IRS coverage required for community benefits to occur vary based on the region and the local strength of transmission (Killeen et al. reported coverage ranging from 35%-65% as adequate for detecting community-level benefits. This was published in the journal PLoS Medicine in 2007). However, most organisations are advocating attempting 80% coverage of bednet use—therefore, large efforts are being made to increase current bednet coverage and IRS efforts, especially in sub-Saharan Africa where the highest number of cases and the highest mortality rates are observed.

Malaria Prevention

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QUESTION

what is the prevention of malaria?

ANSWER

There are many ways in which to prevent malaria. I’ll break them down into three categories: 1) medical prevention, 2) protection from getting mosquito bites and 3) vector control.

1) Medical prevention

Malaria can be prevented using certain medications. Taking drugs to prevent a disease is known as “chemoprophylaxis”, and so these drugs are often referred to as “malaria prophylactics”. There are several different types of malaria prophylactic: the most common ones are chloroquine, a mix of atovaquone and proguanil (marketed as Malarone), mefloquine (marketed as Lariam) and doxycycline. The mode of taking these medications vary (Lariam is taken once a week, for example, whereas the others are usually taken once every day), and they also have different restrictions and side effects. Chloroquine is not effective in areas where local forms of malaria have become resistant, for example, and Lariam is not recommended for people with a history of mental instability, as it is known to cause hallucinations and otherwise impair consciousness. Here on Malaria.com, we are actually currently running a survey on side effects of malaria prophylactic drugs, so if you have ever taken medication to prevent malaria, please take the survey: Malaria Medication Side-effects Survey: Treatment and Prophylaxis

It is worth noting that these drugs have not been tested for long term use, plus they can be expensive if taken for an extended period of time. As such, they may not be appropriate for people living in endemic areas for malaria. However, medication can be useful for preventing malaria in high risk groups, even when they are living in a malaria endemic area. One example is the use of intermittent preventive treatment (IPT) for preventing malaria infection in pregnant women, infants and young children. For more information on this, please see the review article written by Dr Felicia Lester for this website: http://www.malaria.com/research/malaria-pregnancy-preventive-treatment

2) Protection from getting mosquito bites

This section links in with the more general vector control strategies, which will be discussed below. Since malaria is transmitted through the bite of infected mosquitoes, preventing mosquito bites is a very effective way of reducing malaria incidence. One of the most popular methods for personal protection, especially in areas where malaria is endemic, is through sleeping under a mosquito bednet. The mesh prevents mosquitoes from being able to fly close to the person sleeping; however, if there are holes in the net, or the person skin is pressed directly against the mesh, the mosquito may still be able to bite them. This is where insecticide-treated bednets come in – they are impregnated with mosquito repellents to stop mosquitoes from biting through the mesh or passing through holes. Newly developed long-lasting insecticide treated bednets (LLINs) are even more effective, in that they don’t require “re-dipping” to maintain the level of repellent in the fibres, and so can protect a person for several years without losing efficacy. These LLINs have been instrumental in reducing cases of severe and fatal malaria, especially among pregnant women and young children, who are often targeted by bednet distributors.

Other methods for preventing mosquito bites include wearing long-sleeved clothing and personal application of mosquito repellent, particular those containing a percentage of DEET, which is a very effective insecticide. These measures should be especially taken in the evening, early morning and at night, which is when the Anopheles mosquitoes that carry malaria are most active.

3) Vector control

Finally, malaria can be prevented from reducing numbers of mosquitoes directly. Some methods target the adult mosquitoes; one such initiative is indoor residual spraying (IRS), whereby the inside of a house is sprayed with an insecticide to kill mosquitoes. Twelve different insecticides are approved by the World Health Organisation for this purpose, though pyrethroids are among the most popular, as they can be used on a variety of surfaces, do not leave a visible stain and can also protect against other insect pests, such as bedbugs.

Other methods for vector control focus on other parts of the mosquito lifecycle. Mosquito larvae require stagnant freshwater for their development, so some projects have worked to eliminate standing water sources, such as unnecessary ditches and puddles, which reduces the amount of habitat available for mosquitoes to lay their eggs and sustain larvae. Other programmes have spread insecticides directly in stagnant water to kill the larvae, or sought to introduce fish or other aquatic organisms, such as copepods, which consume mosquito eggs and larvae. This latter biological control approach is popular because it can also supply an area with fish for local consumption, and doesn’t contaminate water sources with chemicals.

What is Malaria?

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QUESTION

what is 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.

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).

Symptoms of malaria include fever and flu-like illness, including shaking chills, headache, muscle aches, and tiredness. Nausea, vomiting, and diarrhea may also occur. Malaria may cause anemia and jaundice (yellow coloring of the skin and eyes) because of the loss of red blood cells. Symptoms usually appear between 10 and 15 days after the mosquito bite. If not treated, malaria can quickly become life-threatening by disrupting the blood supply to vital organs. Infection with one type of malaria, Plasmodium falciparum, if not promptly treated, may cause kidney failure, seizures, mental confusion, coma, and death. In many parts of the world, the parasites have developed resistance to a number of malaria medicines.