Repeated Malaria

by

QUESTION

Since January 2011 I got three times malaria. Is it come regularly? Last week also I got maleria and I took medicine but still I have mild headache and sweating feeling tiredenes in between..

ANSWER

The timing of the repeated malaria episodes you have experienced means that it could be recrudescence (where treatment does not completely kill all the malaria parasites in your blood), relapse (where the malaria goes dormant in your liver, then comes back—this is only caused by Plasmodium vivax and Plasmodium ovale malaria) or even re-infection.

However, first of all, the most important thing is to make sure you are properly diagnosed with malaria and secondly, that you receive the right type of treatment for the kind of malaria that you have.

The symptoms of malaria are very general (fever, chills, nausea, tiredness, aches) and can also be caused by many other illnesses and diseases. As such, in order to confirm you actually have malaria, you should have a blood test (thick and thin blood smear, looked at under the microscope by a trained technician, or a rapid diagnostic test (RDT). In some places you can buy these RDTs from local pharmacies and do the test yourself at home).

Depending on where you live, there may be different types of malaria present; in this case, if you do have malaria, it is important to find out which one you have.

P. falciparum is the most common kind in sub-Saharan Africa and first-line treatment is an artemisinin-based combination therapy, such as Coartem – most areas have P. falciparum that is resistant to chloroquine, so this is not appropriate as treatment, nor are sulfadoxine and pyrimethamine combinations (such as Fansidar).

If you have P. vivax or P. ovale, chloroquine may be used, again depending on where you are and whether resistance is known from your area or not. In addition, you might also talk to your doctor about taking primaquine to prevent future relapse and recurrence of the infection.

Repeated re-infection can be prevented by protecting yourself more thoroughly against getting bitten by an infected mosquito. For example, you should sleep under a long-lasting insecticide treated bednet, screen your windows and doors and wear long-sleeved clothing at night and in the evenings. Indoor residual spraying, which coats your walls with insecticide, can also prevent mosquitoes from persisting inside your home.

Information About Malaria

by

QUESTION

What is malaria?

ANSWER

Malaria is a serious and sometimes fatal disease caused by a tiny parasite that commonly infects a certain type of mosquito (of the genus Anopheles) which feeds on humans. People who get malaria are typically very sick with high fevers, shaking chills, and flu-like illness. Four kinds of malaria parasites can infect humans: Plasmodium falciparum, P. vivax, P. ovale, and P. malariae. Infection with P. falciparum, if not promptly treated, may lead to death. Although malaria can be a deadly disease, illness and death from malaria can usually be prevented.

Test for Malaria?

by

QUESTION

Is there a way to verify that someone has had malaria? I had symptoms that were treated with only 10 days of proper 14 days prescription and had a relapse a year later. Have felt weak and keep my drinking to a very light level as a result. Is there test that can be taken to verify having/had plasmodium vivax?

ANSWER

The best way to test for relapsing malaria (i.e. Plasmodium vivax or Plasmodium ovale) is via a blood test while you are experiencing a recurrence of symptoms. Symptoms are associated with the parasite re-entering the blood, and so at this point, they can be visualized on a blood film, or their proteins detecting using a rapid diagnostic test. Other than that, you could also investigate having a serological test done (some forms of these tests are called ELISAs, standing for enzyme-linked immunosorbent assay).

These test for antibodies to specific proteins associated with malaria, and so can be designed to test for a particular strain, such as P. vivax. As antibodies can persist in the blood for weeks or even months after the initial infection has cleared, this could be a way for you to determine whether you had P. vivax without waiting for another relapse. This paper describes the development of a P. vivax-specific serological assay, though I am not sure whether such a test is commercially available as of yet.

If you are diagnosed with Plasmodium vivax, you should ask your doctor about the possibility of taking primaquine to kill the dormant liver stages and prevent future relapse. Primaquine is not recommended for people with G6DP deficiency, so you should be tested for this before taking the medication.

Malaria’s Scientific Name

by

QUESTION

What is malaria’s scientific name?

ANSWER

The genus name for the single-celled parasite which causes malaria is Plasmodium. In the genus, there are five species which infect humans: Plasmodium falciparum (the most deadly kind), P. vivax, P. ovale, P. malariae and P. knowlesi.

Malaria Drug Binding Site

by

QUESTION

What is malaria, and drug binding site?

ANSWER

Malaria is caused by a single-celled protozoan parasite of the genus Plasmodium. Five kinds of Plasmodium are known to infect people: P. falciparum, P. vivax, P. ovale, P. malariae and P. knowlesi.

There is no one drug binding site with respect to malaria: different anti-malarial drugs have different modes of action, and not all are well described. I will briefly outline the proposed mechanism of action of two of the most common types of anti-malarials: artemisinin (and derivatives) and chloroquine (quinine is thought to act similarly to chloroquine).

Artemisinin is thought to have anti-malarial properties by virtue of possessing an endoperoxide moiety, or double oxygen bridge (-Carbon-Oxygen-Oxygen-Carbon). In the presence of intracellular free ion, this moiety is converted by a chemical reaction to “free radicals”, atoms with unpaired electrons which are highly reactive. The free radicals act as alkylating agents and induce cell death, but only those that are already pathologically crippled, for example due to malaria infection. Another hypothesis is that the free radicals directly damage the malaria parasite.

Chloroquine is thought to act by causing buildup of the toxic by-product of hemoglobin metabolism, heme – the malaria parasite usually converts heme to hemozoin, a non-toxic crystal, and stores it in the digestive vacuole. When chloroquine diffuses into an infected red blood cell, it reacts with heme to “cap” it, preventing further conversion into hemozoin. Moreover, chloroquine also converts hemozoin into a highly toxic substance called the FP-Chloroquine complex. This build-up of toxicity leads to breakdown of the cell membrane, and eventual cell death and autodigestion.

When did malaria start?

by

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.

Recurring Malaria

by

QUESTION

I had malaria twice when I was 4 and 8 years old. I am 50 years old now but I have severe chills at least once or twice a month, muscle aches, fatigue severe head aches for the past 10-15 years with no apparent cause and my I take head ache medication for migraine (maxalt and excedrim) and my chills and fatigue is getting more frequent. I had no other history of any diseases. Is this symptoms a possible recurrent malaria.

ANSWER

Thanks for your question. One of the most common symptoms of malaria is high fever, which comes in cycles with chills in between. Without fever, it is unlikely that you are suffering from malaria.

However, there are some forms of malaria which can cause relapses. Specifically, Plasmodium vivax and P. ovale can form dormant liver stages which can then re-enter the blood causing a relapse of malaria infection and a recurrence of symptoms. To diagnose malaria in your case, next time you have an episode of chills, go to your doctor and ask for a blood test to check for malaria. S/he will either look at your blood under the microscope or perform a rapid diagnostic test, which tests for malaria-specific proteins, called antigens, in your blood.

In either case, it will tell you whether you have malaria, and which kind. If you have one of the relapsing kinds (P. vivax  or P. ovale) then you may be able to take a course of a drug called primaquine which kills the dormant liver forms of the malaria parasite and thus prevents future relapses. However, people with G6DP deficiency should not take primaquine, so you should be tested for this deficiency prior to taking the drug.

Evolution of Malaria

by

QUESTION

how did malaria evolve?

ANSWER

Malaria in humans probably evolved independently several times, and both times likely due to a cross-over event from a closely related primate malaria. For example, Plasmodium vivax is evolutionarily closely related to several species of malaria found in macaque monkeys in south-east Asia, and so a cross-over of one of those species into human, with subsequent adaptation and speciation, is one hypothesis as to the origin of P. vivax. Conversely, some people argue that P. vivax emerged in Africa, due to the high prevalence of certain genetic traits in African populations (such as the Duffy negative antigen), which protect against P. vivax.

In contrast, P. falciparum is agreed to have emerged in sub-Saharan Africa, and likely in the Congo basin, though the exact source of its origin has been under recent scientific dispute. Until 2010, it was thought that P. falciparum had crossed over to humans from chimpanzees, as chimps are known to be infected with P. reichenowi, a species very closely related to P. falciparum. However, a paper was published in 2010 which had sampled Plasmodium parasites of gorillas and revealed new species of Plasmodium which are even more closely related to P. falciparum, suggesting that the cross-over occurred from gorillas to humans.

As you can see, humans are not the only primates to get malaria; many species of monkey and ape are also susceptible to Plasmodium species, and even lemurs have their own suite of Plasmodium parasites. Among the mammals, rodents also can get malaria, and bats are infected with Hepatocystis, a malaria-like parasite which also infects hippos, primates and rodents. However, no other species of mammal appears to be susceptible to Plasmodium/Hepatocystis, and the reasons for this are not entirely clear.

Plasmodium probably crossed over to mammals from birds or lizards, both of which are infected with a vast number of species of Plasmodium. It is unclear in which of these groups Plasmodium first emerged, though it likely evolved originally from another type of blood-borne parasite called Leucocytozoon, which infects birds and uses blackflies (genus Simulium) as vectors.

A sister group to Plasmodium, called Haemoproteus, also evolved from Leucocytozoon but utilises a variety of different vectors, including mosquitoes, biting midges (Culicoides), louse flies (Hippoboscidae) and tabanids (Tabanidae). Plasmodium, by contrast, exclusively uses mosquitoes as its vectors (apart from one species of lizard Plasmodium, P. mexicanum, which uses sandflies), but while mammalian Plasmodium is only transmitted by Anopheles mosquitoes, bird and lizard Plasmodium can be transmitted by Culex, Aedes, Culiseta, Anopheles, Mansonia and Psorophora. As such, understanding the patterns of vector and host switches within Plasmodium and related taxa can actually provide interesting insights into the genus’ evolutionary history.

Thalassaemia and Malaria

by

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

by

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)