What are the symptoms of malaria?

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QUESTION

What are the symptoms of malaria?

ANSWER

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.

Frequent Fever

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QUESTION

I live in Mumbai,India. My mother’s age is 56. She is getting fever from last 1 month and also lost her appetite. We have tested for malaria but it is negative. Tried 4-5 doctors but no one is able to detect the exact cause. She feels better for 3-4 days after medication but then again gets a fever. She feels like vomiting while trying to eat something. Please help.

ANSWER

If the doctors have tested her for malaria and the test was negative, then she probably isn’t suffering from malaria. There are many other potential causes for her illness, from influenza to gastroenteritis. She should try to keep drinking plenty of fluids to stay rehydrated, and plain foods so as not to upset her stomach but keep her strength up. We are not able to give specific medical advice. If she is still feeling sick, you should consult another doctor and ask for a more comprehensive set of tests to determine the cause of illness (including blood tests and a faecal examination to look for parasites).

Malaria in Mosquitoes

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QUESTION

Why can’t mosquitoes become sick of malaria? What do they have in their system that prevent them from becoming sick yet they transmit the disease to humans?

ANSWER

First of all, mosquitoes do get “sick” when infected with malaria, though not in the same way as humans. This is due to the major differences between human and mosquito physiology and also differences in the life stage of the malaria parasite between the different hosts.

Humans get sick from malaria because the malaria parasite, when inside the human host, sequentially infects red blood cells, multiplying inside them and then destroying them. This process of destruction and the resultant debris in the blood results fever and other symptoms (some of which are exacerbated by the body’s immune response).

Mosquitoes are insects, and do not have blood in the same way as humans. Instead, in the mosquito, the malaria parasites differentiate into male and female life stages (called gametocytes) which fuse into the mosquitoes gut. After further reproduction, they eventually produce sporozoites that rupture out of the mosquito gut wall and migrate to the salivary glands, where they can be infected into a new human host.  

Mosquitoes also have a very different immune system to humans, and so the concept of “sick” is not the same for them as for humans. However, there is a lot of evidence that infection with malaria results in reduced reproductive success for the mosquito, as well as lower survival. This could be due to protective responses on the part of the mosquito, but also could be mediated by the malaria parasite, by diverted resources towards its own development that could have been used for mosquito reproduction or survival.

When did malaria start?

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QUESTION

What year did malaria start?

ANSWER

Malaria first emerged as an infection of humans tens of thousands, if not hundreds of thousands, of years ago. The species of malaria that infect humans probably evolved from closely related malaria species that infect macaques (in the case of Plasmodium vivax) and gorillas (in the case of P. falciparum).

The earliest records from human history of malaria come from a Chinese medical parchment almost 5000 years ago, and it is believed the ancient Egyptians also recognised the symptoms of the disease. Written accounts of malaria also occur in ancient Roman and Greek texts, though the true causes of malaria were not discovered until the 19th century.

Malaria Vaccine Research

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QUESTION

Is there any research to produce anti malaria vaccine, if not, why?

ANSWER

There are many teams of scientists working hard to try to produce a malaria vaccine. In fact, only last year, the preliminary results of a vaccine trial were published. The vaccine, called RTS,S, has been produced by GlaxoSmithKline and is in the midst of Phase III trials in Africa. The preliminary results showed approximately a 50% reduction in malaria incidence, though it is not clear how much of that protection came from the vaccine and how much should be attributed to the vaccine adjunct (a compound given with the vaccine to boost immune responses).

The preliminary results also did not include analysis of how much the vaccine prevented mortality due to malaria, and levels of protection against severe malaria appeared to be low. However, we will have to wait until 2014 for the full and final results of the clinical trial to be made available. In the meantime, other vaccine candidates are being developed, but there are many challenges to overcome.

For example, there are five different types of malaria that infect people: these differ significantly in the way they develop in the human host, and so a vaccine appropriate for one may not be effective against the others. Most vaccine researchers are focusing on Plasmodium falciparum, the most deadly form of malaria, and a vaccine effective against this parasite would certainly do the most to reduce malaria-related mortality. However, Plasmodium vivax also causes high morbidity, particularly in Asia and the Pacific, and so should not be overlooked.

Moreover, within each of these species exist different strains in different areas, each of which can be markedly different from a genetic perspective. Finally, we do not yet fully understand the complex ways in which our immune system reacts to malaria. As such, this presents a challenge to developing an effective malaria vaccine, though many scientists are willing to address this challenge and have made big inroads in the search for a safe, effective vaccine. For more information on current efforts to develop a malaria vaccine, please see PATH’s Malaria Vaccine Initiative.

Malaria Transmission and Deaths in the United States

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QUESTION

How do you get malaria? How does malaria come to the United States? How many people have died from malaria?

ANSWER

Malaria is caused by infection with single-celled parasites called Plasmodium. There are five different species which infect humans; of these, Plasmodium falciparum is the most deadly. The Plasmodium parasites are transmitted to humans through the bite of an infected female Anopheles mosquito; when these mosquitoes bite a human, they transfer some of the parasites in their saliva.

After undergoing one set of multiplications in the liver, the malaria parasites are released into the blood, where they repeatedly infect and destroy red blood cells, multiplying in the process. These cycles of infection and destruction of red blood cells cause the cyclical fever that is characteristic of malaria. Eventually, the parasite produces new types of cells, called gametocytes; if the patient is then bitten by another mosquito, the mosquito can take up gametocytes as well as blood when it feeds, and the cycle continues.

Malaria used to be relatively common in the United States, though usually only occurring during the summer months and restricted to the warm, wet south-eastern region. However, a concerted control campaign in the 1940s, focusing mainly on vector control (i.e. killing mosquito and reducing their opportunities for breeding) swiftly led to the eradication of malaria from the US.

Nowadays, virtually all malaria cases in the US are imported from abroad, whereby people get infected when traveling to other countries, but are only diagnosed as having malaria when they return home. There are about 1,000 cases of malaria reported each year in the US, and most of these were actually caught outside the US. Very rarely, an Anopheles mosquito will bite one of these travelers once they have returned from abroad, and therefore have the potential to transmit malaria within the US. However, due to a strong public health network and good access to malaria diagnosis and treatment, these events rarely lead to more than a handful of cases before they are quickly treated and transmission eliminated again.

The World Health Organisation estimates that last year, approximately 700,000 people died of malaria. Of these, 90% were in sub-Saharan Africa, and the vast majority were children under the age of 5.

Three Stages of Malaria

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QUESTION

What are the three stages of malaria?

ANSWER

The three parts of the malaria life cycle are known as the exo-erythrocytic cycle, the erythrocytic cycle and the sporogonic cycle. The first two of these take place in the human (or other mammal) host, while the third occurs in the mosquito vector. The below diagram, courtesy of the CDC, shows the complete life cycle of malaria in more detail.

malaria life cycle CDC

Schematic of the malaria life cycle, courtesy of the CDC (www.cdc.gov)

P. Falciparum Malaria Treatment

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QUESTION

I dont have high fever yet have been diagnosed with P. falciparum malaria. How can this disease be treated and is it completely curable?

ANSWER

Don’t worry, if diagnosed early and given appropriate treatment, P. falciparum infection is very easily cured. You should be given a type of medication called artemisinin-based combination therapy (ACT). An example is Coartem, which is a combination of artemether and lumefantrine.

Other artemisinin derivatives that are commonly used include artesunate and dihydroartemisinin. You should start to feel better after just a few days and will make a complete recovery. Make sure you get the correct dose for your age and weight from the doctor, and take the medication for the full length of time the doctor tells you – this is very important to make sure the infection is completely cured, otherwise the infection may be able to come back.

What is malaria, and what causes it?

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QUESTION

What is malaria and what causes it?

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).

Cyclical Fever and Malaria Symptoms

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QUESTION

My dad is not well from last one month. In the evening time he feels headache, neck pain and 102 Temp.

Can you please tell me can it be Malaria.

ANSWER

Those symptoms can be characteristic of malaria—cyclical fever is a key symptom, though usually the cycles are every other day or even every third day (depending on the type of malaria). However, in some cases the cycles are more frequent or the patient may even have constant fever.

One of the difficulties with diagnosing malaria is that its symptoms are very general and can therefore be mistaken for many other illnesses. Likewise, in areas of high malaria transmission, doctors may assume a feverish illness is malaria without thinking about other possible diseases. As such, it is crucial that you take your father for a blood test, which is the only accurate way to diagnose malaria.

The doctor or clinician will either make a blood film and look at it under the microscope, or use a tiny drop of blood in a rapid diagnostic test. Either way, it is important for them to see evidence of a malaria infection before they give your father treatment. The diagnostic test should also show which type of malaria your father has (if indeed he has malaria), and this will also help to determine which is the most appropriate type of medication.