Introduction of malaria

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QUESTION:

What is the introduction of malaria?

ANSWER:

Malaria is introduced into the human host via mosquitoes, who pass the parasite into the human blood stream through their mouthparts as they take a blood meal. Since the development of both the mosquito and the parasite are temperature-dependent, and tend to favour warm, humid conditions (mosquito larvae require pools of still water to develop into adults), the distribution of malaria is limited to parts of the world where these temperature and humidity conditions are met.

However, cases of malaria can also be introduced into other parts of the world by travellers coming from malarial regions or by mosquitoes, already infected with malaria, being accidentally transported into non-malarial countries in aeroplanes or in ships. These kinds of introductions resulted in about 1500 cases of malaria reported in the United States in 2007, a country which is usually free of malarial transmission. These introductions are rare, and also short lived, as the conditions do not favour the continued survival of the transmission cycle. However, this is one of the worries regarding climate change; it may make some areas of the world, which currently do not have malaria, more climatically suited to transmission of the disease, thus allowing for introductions of the mosquitoes and the parasite in the future.

How does malaria spread?

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QUESTION:

How does malaria spread?

ANSWER:

Malaria is a vector-borne disease; this means that it has to be spread through a “vector” species, which in this case are female mosquitoes of the genus Anopheles. The female mosquito needs to feed on blood in order to produce eggs; most species lay eggs every 2-3 days, which means each female mosquito needs to take very regular blood meals.

Around 20 species of Anopheles mosquito have been implicated in the transmission of malaria; some species are better than others at acting as a vector. The most important group in Africa is the Anopheles gambiae complex; these mosquitoes are also relatively long-lived, which is important for transmission since it means that whole portions of the malaria parasite’s life cycle can be completed inside the vector mosquito.

When the female mosquito takes a blood meal, she inserts her slender mouth part (called a ‘proboscis’) into a tiny cut she makes uses specialized slicing parts of her mouth. She probes until she finds a small surface blood vessel, from which she feeds. The proboscis contains two narrow tubes – one delivers her own saliva into the wound (containing chemicals to stop the blood coagulating as well as a slight pain-killer, to stop you feeling the bite) while the other sucks up blood.

The mosquito’s saliva also contains the malaria parasite; this is how the parasite is delivered into the human body. Similarly, the parasite passes back into the mosquito through the blood she ingests, once the human portion of the life cycle has been completed. As mosquitoes pass between human to human, and indeed also between other animals, they spread the malaria parasite through the delivery of saliva and the uptake of blood.

What is malaria? What Causes Malaria?

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QUESTIONS:

What is malaria?
What causes malaria?

ANSWER:

I have copied below the text from an earlier question, also asking about the causes of malaria and explaining what it is:

Malaria is a disease caused by a parasitic single-celled animal known as Plasmodium. There are different species of Plasmodium, which cause different kinds of malaria. The main types which infect humans are P. falciparum, P. vivax, P. ovale and P. malariae. The parasite is transmitted by certain species of mosquito; the parasite lives in the human blood stream and so goes in to the mosquito when the insect feeds. When the same individual mosquito then feeds on another person, it transmits parasites into a new host.

The symptoms of malaria are caused by the actions that the parasite undertakes while in the human host. For example, part of its reproductive cycle involves invading and then multiplying inside red blood cells. Once several cycles of reproduction have occurred, the new parasites burst out of the red blood cell, destroying it. The cycles are times so that all the new parasites burst out of the red blood cells at the same time; this coordinated destruction of the red blood cells, either every 24, 48 or 72 hours, depending on the malaria species, causes the one day, two day or three day cycles of fevers and chills that characterize malaria infection episodes.


Incidence of malaria in Quito, Ecuador

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QUESTION:

What is the number of cases of malaria reported in Quito, Ecuador? In 1940 was it a common problem?

ANSWER:

There is no transmission of malaria in Quito – it is at too high an altitude! Transmission of malaria in Ecuador is estimated to stop at around 1500m of altitude, and the central plaza of Quito, Plaza Grande, sits at almost 3000m! As such, even in 1940 malaria in Quito would not have been a problem. However, there may still be a small number of reported cases even at such altitudes each year – this is due to people who get infected with malaria from mosquito bites at lower altitudes, such as in much of the rainforest and coastal regions of Ecuador, and then travel back up to the highlands before the first symptoms appear, which can be as long as two weeks after exposure to the parasite.

As mentioned briefly above, although Quito, Guayaquil, the central highlands and the Galapagos Islands are considered areas with low to no malaria transmission, travellers to or residents in other parts of Ecuador should take precautions against getting bitten by mosquitoes, such as long-sleeved clothing in the evenings and sleeping under an insecticide-treated bednet at night. They might also consider taking preventative medication, also known as prophylaxis, against malaria. As this can be expensive long-term, this is usually only used by travellers rather than residents in malarial regions. There are several different types of medication that can be taken; since chloroquine resistant types of malaria are known to occur in Ecuador, Lariam, doxycyline and Malarone are the main types of prophylaxis recommended for this country.

Are these malaria symptoms?

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QUESTION:

My daughter (10yrs) had high fever with chills till 4 days back but now she has low or no fever but feels cold at intervals & for that duration she is feeling giddy & vomittish. A little cough is also their . During this duration she is very uncomfortable & feels she has very high fever. Does all this reflect as malaria symptoms or it is some other problem. Please respond immediately with your suggestions.

ANSWER:

The best thing to do would be to take your daughter IMMEDIATELY to a hospital or to see a doctor. Her symptoms are consistent with malaria, but likewise could be caused by a number of other diseases. The only way to know for sure whether she has malaria is through diagnosis via a blood film or blood test – such diagnosis is crucial to ensure that she is treated promptly and accurately.

Malaria Treatment

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QUESTION:

What is the proper treatment for people with malaria symptoms?

ANSWER:

The proper treatment for malaria depends on the type of malaria parasite that the patient is infected with. Therefore, before treatment begins, the patient should be accurately diagnosed.

In most cases of non-Plasmodium falciparum malaria (the most deadly form of malaria, found throughout the world but most prevalent in sub-Saharan Africa), and even in some places where P. falciparum has not yet developed resistance, treatment with chloroquine is sufficient.

The dosage will depend on body weight (usually approximated by age). Where there is a risk of chloroquine-resistant malaria occurring, treatment of non-complicated cases will usually consist of orally-administered artemisinin-based combination therapy (or ACT) – again, the dosage will depend on age/weight.

For severe malaria, parenteral ingestion of drugs is required. For the treatment of cerebral malaria, caused by P. falciparum, quinine is the traditional drug of choice, though artemisinin has also been shown to be effective. Anti-convulsants and anti-pyretics (to reduce fever) should also be administered.

In cases of infection with P. vivax or P. ovale, the parasite can become dormant in the liver and result in a relapse of the disease if not treated properly. As such, patients with either of these forms of malaria should also be treated with primaquine.

If you have, or suspect you have a health problem, you should visit a physician for a medical diagnosis and treatment.

What is Malaria?

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QUESTION:

What is malaria?

ANSWER:

Malaria is a disease caused by parasites of the genus Plasmodium. Transmitted by mosquitoes, there are several different kinds of malaria distributed throughout the tropical and sub-tropical regions of the world, causing somewhere between 300-500 million cases of disease each year, and as many as 1 million deaths. In fact, malaria is one of the biggest killers of children under the age of five in sub-Saharan Africa, one of the regions of the world where the burden from malaria is the highest. Malaria is usually an acute disease, manifesting itself with severe fever, chills, headache and often nausea as well. Some types of malaria can have relapsing episodes over a time period of many years.

Having said this, malaria is easily preventable, through avoiding mosquito bites by wearing appropriate clothing and sleeping under insecticide-treated bednets, or through taking preventative medication (called prophylaxis). Malaria is also treatable once symptoms appear, through ingesting safe, effective and relatively cheap drugs. With such control measures at hand, you may ask why malaria is still such a huge problem in our world; the answer is that delivering control strategies and treatment to populations most at risk is difficult, and often countries with high malaria burdens don’t have efficient and effective health systems in place to coordinate control efforts.

International non-governmental organisations such as the World Health Organisation, as well as a multitude of non-profit organisations such as the Malaria Consortium and Malaria No More, work tirelessly to bring malaria control and treatment to the places that need it most, with the aim to eradicate malaria as a disease of public health importance.

Malaria symptoms

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QUESTION:

When a person is ill he or she will have what symptoms?

ANSWER:

Malaria can have many different symptoms, but the initial signs are similar to a flu-like illness, with high fever, chills, headache and muscle soreness or aches. A characteristic sign of malaria is cyclical fever, with peaks of severity every two or three days. Additionally, some people will experience nausea, coughing, vomiting and/or diarrhea.

Because these symptoms are quite generic of a wide variety of illnesses, if you live in a malaria-endemic region, it is crucial to be tested when you develop such symptoms, rather than assuming it’s just the flu and soldiering on! If you have recently traveled to a malarial area and start to experience these signs of infection, similarly you should inform your doctor of your travel history, as otherwise they might not recognize your symptoms as potentially that of malaria.

If treated rapidly and with the correct medication, malaria is almost always completely treatable; it is only if treatment is delayed that it becomes more serious, with long-lasting and potentially fatal consequences. Similarly, if you take sensible precautions while living or traveling in malarial areas, such as taking prophylaxis (and taking them as per the instructions, for the full required amount of time!), avoiding being bitten by mosquitoes and sleeping under an insecticide-treated bed-net, you vastly reduce your chances of getting infected in the first place.

It’s also worth noting that different species of Plasmodium, the parasite that causes malaria, cause slightly different manifestations of the disease, and also require different forms of treatment. Plasmodium falciparum has a unique way of affecting the red blood cells it infects, which eventually can result in loss of function of internal organs. ‘Cerebral malaria’ is a particularly deadly version of this, whereby the function of the brain is affected. The cycles of fever, mentioned above, are caused by synchronous rupturing of the red blood cells in the body by the malaria parasite; P. falciparum, P. vivax and P. ovale complete this cycle every 48 hours, resulting in fever cycles of roughly two days (though P. falciparum can be unpredictable); P. malariae, on the other hand, has a cycle lasting 72 hours, so three day cycles of fever are expected. Finally, although many types of malaria can be successfully treated with the drug chloroquine, some strains, and notably of P. falciparum, have become resistant to this treatment. In these cases, artemesinin-based treatment is recommended, usually in combination with other therapies (artemesinin-combination therapy, or ACT). P. vivax, in addition, requires an additional drug, called primaquine, which is used to treat lingering liver stages of the parasite, to prevent recurrence of the infection.

Malaria Treatment

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QUESTION:

Is there any treatment for malaria?

ANSWER:

Yes, treatment is available for malaria and most cases can be cured easily if diagnosed accurately and early. There are several different drugs that are used to treat malaria, and different modes of ingestion.

Most cases of malaria can be treated effectively with oral drugs, usually artemisinin-based combination therapies (which contain a drug called artemisinin, long used in Chinese medicine to treat malaria) or chloroquine. The choice between these will depend on the type of malaria you have (hence the need for accurate diagnosis) as well as whether the area you are in is known to have types of malaria that are resistant to chloroquine. In addition, some types of malaria, notably P. vivax and P. ovale, require an additional drug, known as primaquine, to prevent later relapses of malaria from dormant forms of the parasite, that hide in the liver.

Severe malaria may require the administration of drugs directly into the body, usually intravenously. Quinine is often the first-choice drug at this stage, though artemisinin-based compounds have also been shown to be effective. Severe malaria, sometimes manifesting as cerebral malaria, is usually only caused by P. falciparum, the most deadly of the types of malaria found in humans.

Does malaria affect population vigour?

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QUESTION:

How is malaria affecting population vigour at present?

ANSWER:

If I understand your question correctly, you are asking if malaria affects the well-being of populations. In answer, malaria is an extremely debilitating disease in many populations around the world, and is known to severely affect population vigour.

People infected with malaria are likely to miss work or school, and of course are at risk of dying from the disease as well. There is, moreover, an intimate association between malaria and poverty, with malaria both being considered a disease caused by poverty as well as a cause of it – malaria is known to result in lost productivity through absenteeism, permanent neurological damage caused by severe disease episodes, and changes in economic or investment decisions based on presence of malaria.

One estimate is that a combination of the above indirect costs of malaria, together with direct costs on the healthcare infrastructure, cost Africa as much as $12 billion per year in lost economic output. A review on the link between poverty and malaria was written in 2002 by Jeffrey Sachs and Pia Malaney for the scientific journal Nature.

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