Dangerous

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QUESTION

Why malaria so dangerous?

ANSWER

Malaria can be dangerous for a number of different reasons, some of which relate to each other. First of all, there are five different types of malaria that infect humans, and each varies in terms of its severity and potential for severe consequences. Even within these types, the severity of the disease caused (termed “virulence” by scientists and doctors), can even vary by strain or geography. Generally, the most dangerous form of malaria is caused by Plasmodium falciparum. One reason why this species of malaria is so dangerous is that is replicates very quickly in the blood. This means that infection levels can build up very quickly; if a person infected with P. falciparum does not get diagnosed and treated within a few days of feeling sick, the infection can progress to a point where the disease becomes very severe. This rapid accumulation of infection is also observed with P. knowlesi, a much rarer form of malaria found in south-east Asia. The parasites of P. knowlesi have a 24-hour reproductive cycle in the blood, the quickest for any type of malaria that infects humans. However, P. falciparum also has other characteristics which make it even more dangerous, and which do not occur with P. knowlesi. For example, when P. falciparum infects red blood cells, it causes their shape to change, and makes them “sticky”. This stickiness causes the red blood cells to become lodged in the blood vessels leading in to major organs, in a process known as sequestration. Sequestration creates blockages of these blood vessels, reducing blood flow and resulting in oxygen deprivation. When this process occurs in the blood vessels in the brain, the outcome is known as cerebral malaria, characterised by impaired consciousness, coma and even death. It is this pathology which is associated with most cases of severe malaria, and causes the most number of deaths.

However, if treated promptly with the correct drugs, even P. falciparum malaria is usually easily controlled. Therefore, one of the additional reasons why malaria is so dangerous is that in many places, and particularly sub-Saharan Africa, people do not have access to medication, or not the right types of medication. Many strains of P. falciparum have become resistant to chloroquine, once the first line treatment for malaria, and so this drugs is now ineffective in many cases. Instead, the World Health Organisation recommends now that artemisinin-based combination therapies (ACTs, such as Coartem) should be given as first-line treatment against all uncomplicated malaria, to prevent additional resistance from developing.

Thalassaemia and Malaria

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QUESTION

How can Thalassaemia effect Malaria infection?

ANSWER

Thalassaemia is the name given to a group of inherited genetic blood disorders, which result in reduced or no synthesis of one of the globin protein chains that combine to make haemaglobin. Haemaglobin is used to carry oxygen throughout the body and to its organs.

Thalassaemia can result in anaemia; in some cases, this is severe enough to require periodic blood transfusions. There has long been a hypothesis that thalassaemia might have persisted due to conveying protection against malaria infection; this was suggested due to the geographical distributions of populations with high prevalence of the alleles (gene types) that cause thalassaemia and areas with high levels of malaria transmission. However, scientifically confirming this association has proved challenging.

A recent study from Kenya demonstrated that children with either one copy of the thalassaemia allele or two copies appeared to have a reduced incidence of severe malaria, fewer deaths from malaria and were hospitalized less frequently for malaria. However, they were just as likely as non-thalassaemic children to have mild or sub-clinical malaria, and the same levels of parasitaemia (numbers of parasites in the blood).

A contrasting study from Vanuatu observed higher incidences of severe malaria in children with thalassaemia, though one potential confounding factor in comparing these studies is that the Vanuatu study looked at both P. falciparum and P. vivax, whereas the Kenya study only looked at P. falciparum malaria.

The difference is significant: one of the proposed mechanisms by which thalassaemia protects against malaria is by preventing modification of the surface of red blood cells, which causes the red blood cells to become “sticky” and sequester within the blood vessels that feed major organs, eventually restricting blood flow and causing major complications. This sequestration is only observed to occur during infection with P. falciparum, and so thalassaemia might not be as protective against other forms of malaria. More empirical research from the field is needed to understand the mechanisms relating malaria infection with thalassaemia more fully.

Malaria Parasite Picture

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QUESTION

Please show parasites pictures.

ANSWER

The first plate below shows various stages of the life cycle of Plasmodium falciparum, the most deadly form of malaria, and the most commonly found type in sub-Saharan Africa. Below that, a similar plate shows a series of images of Plasmodium vivax, the most widespread type of malaria.

A: The stages of P. falciparum. 1: Normal red cell; Figs. 2-18: Trophozoites (among these, Figs. 2-10 correspond to ring-stage trophozoites); Figs. 19-26: Schizonts (Fig. 26 is a ruptured schizont); Figs. 27, 28: Mature macrogametocytes (female); Figs. 29, 30: Mature microgametocytes (male). Illustrations from: Coatney GR, Collins WE, Warren M, Contacos PG. “The Primate Malarias”. Bethesda: U.S. Department of Health, Education and Welfare; 1971. Reproduced here courtesy of the CDC (www.cdc.gov)

 

 

Where is malaria found?

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QUESTION

Where is malaria found?

ANSWER

Malaria is found throughout the world’s tropical and sub-tropical areas, and mainly in Central and South America, Africa, Asia and the Indo-Pacific region. It is most common in tropical regions, where transmission occurs year-round; in sub-tropical and temperate areas, transmission may only occur during seasons that have appropriate climatic conditions. This includes sufficiently high temperature and water availability for the growth and development of the mosquito, which transmits the disease. Currently, the greatest burden of the disease is felt in sub-Saharan Africa, where over 90% of deaths due to malaria occur. The map below shows the estimated risk for malaria across the world, courtesy of the World Health Organisation.

Global_Malaria_2010_WHO

Map of the global distribution of malaria, courtesy of WHO (www.who.org)

Dietary recommedations

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QUESTION

Can I have the dietary recommendations please.

ANSWER

I am afraid I do not completely understand your question. There are no known dietary measures that can be used to prevent malaria infection, nor are there and recommended ways of treating malaria with common foods. In the past, people drank tonic water, which contained quinine, as a way of preventing and treating malaria. However, in modern times, tonic water contains very low levels of quinine, insufficient to protect against malaria. More effective means of prevention, such as prophylactic medication and sleeping under a long-lasting insecticide treated bednet, are recommended instead.

Malaria Relapse

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QUESTION

Why do I suffer from constant malaria attack? The doctor has prescribed different prescriptions every time I get an attack but its still coming back. What could be the problem?

ANSWER

There are a number of possible answers to your question. First of all, your doctor might not be prescribing the right type of treatment for the type of malaria that you have. The World Health Organisation now recommends that all uncomplicated cases of malaria should be treated with artemisinin-based combination therapies (ACTs), such a Coartem. However, in some places, doctors still prescribe other drugs, such as Fansidar or chloroquine. This can be a problem, as in many areas, the local kinds of malaria have become resistant to these earlier drugs, and so you may not be cleared of the infection. This is called recrudescence—when a malaria infection is not cleared completely from the blood and so symptoms come back once the treatment has stopped.

Alternatively, if there is a longer time interval between your episodes of illness, you may be suffering from relapses. This occurs with two particular types of malaria: Plasmodium vivax and P. ovale. These types of malaria can form liver stages which remain dormant even after the treatment you take kills all the malaria in your blood. Therefore it will appear like you have been cured, but really you still have an infection in the liver.

These liver stages can re-activate and re-enter the blood, causing another episode of malaria symptoms months or even years after the initial infection. If your doctor finds that you are positive for one of these two types of malaria, you should talk to him/her about the possibility of taking primaquine. This drug kills the liver stages of the parasite, but is not appropriate for people with G6DP deficiency, so you should be tested for that first.

Finally, there is the possibility that you are continually being re-infected with malaria. In this case, you should take more preventative precautions. For example, sleep under a long-lasting insecticide-treated bednet, wear long-sleeved clothing (especially at night) and cover exposed skin with insect repellent. All of these measures will help prevent mosquito bites, which transmit malaria. In addition, you could consider indoor residual spraying, which coats the walls inside your house with insecticide to further eliminate the presence of mosquitoes.

When to Seek Malaria Treatment

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QUESTION

I have been in New Guinea recently and 2 weeks on am exhibiting all the signs and symptoms of malaria. What is best course of action, considering I do not know what sort of mosquito was hovering about?

ANSWER

You should visit your physician or a clinic immediately. Depending on where you are, you may have to visit a specialist travel medicine clinic, to be sure that you will be seen by someone who understands how best to diagnose malaria. They should take blood and examine it under a microscope (using thick and thin blood films), or they may utilise a rapid diagnostic test. Either way, they will be able to determine whether you have malaria and if so, which type of malaria you have. 

This is important because some types of malaria, such as Plasmodium vivax (which is very common in PNG) can remain dormant in the liver after the initial infection has been treated, which leads to relapses months or years later. In order to prevent relapses, if you find you are infected with P. vivax you should inquire about the possibility of also being given primaquine, which is a drug that can kill these liver stages.

Frequent Urination and Malaria

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QUESTION

Can malaria result in frequent urination, especially during night?

ANSWER

Malaria can affect the kidneys, especially malaria caused by P. falciparum. This could result in changes to urination patterns. However, at this stage in the infection, the patient would also be experiencing severe fever, chills and other symptoms associated with malaria. The fever would also likely be causing dehydration if the patient was not taking on sufficient fluids, which would result in less frequent urination.

Can malaria be dormant for years?

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QUESTION

My child (age 5 at time) was bitten by something in Mexico that looked like a mosquito bite. About 7 days later we were home in the US and she developed high fever, headache, chills,sweating at night, extreme fatigue,abdominal pain, and swollen lymph nodes in neck. She had a fever for 40 days! I took her to the pediatrician almost every other day and had immediately informed them of the bite in Mexico and asked if they could test her for malaria. They laughed at me and said that is not high malaria area.

Her wbc was 30,000ish and liver enzymes 1000–tons of other blood work got lost. I had researched and agreed but told them it still exits there even if it is low. So 3 years later she still has swollen lymph nodes in neck that are bigger and now in the axillary and groin area, always sweats in the middle of the night, pale, and very tired. Dr. tells me not to worry about the lymph nodes but it is hard not to. I have bypassed her finally and talked with an infectious disease doctor that suggested we get a lymphnode biopsy. We have an appt w/an hem/onc Dr in 5 days. If they were to biopsy a lymph node could it show Malaria this late or would it have to be the liver or could they do a blood smear this late? She also has had low amounts of myoglobin in her urine for about a year.

ANSWER

I replied to an earlier version of this post—reading your subsequent details, I think it is unlikely that the cause is malaria, but rather an infection or indeed another disorder which would result in elevated WBC and enlarged lymph nodes. A biopsy at this stage would not be able to diagnose malaria—a blood test would only reveal an active, blood-borne infection, which would be associated with high fever and other “typical” malaria symptoms. If your daughter is experiencing these (though fever/sweats at night are not particularly associated with malaria), a blood test could put your mind at rest by eliminating malaria as a cause. However your pediatrician will be better placed to discuss other possible diagnoses which correspond to the symptoms.

Is malaria infectious?

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QUESTION

Is malaria infectious or noninfectious?

ANSWER

Malaria is considered an infectious disease because it can be transmitted from one person to another, via the bite of an infected mosquito. Since the parasite that causes malaria is passed through the blood, it can also be transmitted via organ transplant, blood transfusion, or via pregnancy (so-called “congenital” malaria).