Can Malaria Penetrate the Brain

by

QUESTION

Can malaria penetrate the brain?

 

ANSWER

Approximately 1% of people with malaria will develop a severe form, and in these cases the brain can be affected.  When the brain is affected, the condition is called cerebral malaria.  Functional changes to the blood-brain barrier occur in cerebral malaria, possibly as a result of the binding of parasitized red blood cells to cerebral endothelial cells,  although scientists do not really understand the mechanism.  However, people suffering from cerebral malaria can have seizures, fall into a coma, or show other neurological problems.

Without treatment, cerebral malaria generally leads to death.  Among children with cerebral malaria who received treatment and survived, it has been found that about a quarter (25%) have long-term problems with thought processes, motor function or have behavior impairments and  10% develop epilepsy.

Malaria: Should I See a Doctor?

by

QUESTION

For the last couple of days I am suffering from all the symptoms that are mentioned on your website and I am taking tylenol for these symptoms thinking that it is flu but I am feeling better now. Should I still see a doctor or keep taking Tylenol?

ANSWER

Symptoms of malaria often include high fever, aches, chills, nausea, and headache.  When severe, malaria can lead to anemia, impaired consciousness and even coma or death.  The best course of action is to get a simple blood test to check if you have malaria, because if you do have it,  early treatment with the appropriate drug (for the type of malaria you have), is essential.

You should also know how to prevent getting malaria. The first thing to do is to make sure you are protecting yourself sufficiently from mosquito bites. You can’t get malaria if you aren’t bitten by mosquitoes, and the type of mosquitoes that transmit malaria usually bite at night. As such, it is crucial to sleep every night under a long-lasting insecticide treated bednet. If you have one, it might need to be re-dipped in insecticide to make sure it keeps working effectively. Also, you should make sure all your windows and doors are properly screened to prevent mosquitoes from coming in; many people also do something called “indoor residual spraying” where they spray insecticide on the walls inside their house to kill any mosquitoes which might come in. If you live in an urban area, this might not be necessary if you can get good screens, or indeed if you have air conditioning (mosquitoes do not like cooler environments). Finally, you should try to wear long-sleeved clothing in the evenings and at night, again to stop mosquitoes from biting.

Can Malaria Cause Blindness?

by

QUESTION

Can you please help us? My husband got severe malaria and now he’s blind. He stayed 33 days in hospital.

We live in Portugal. My husband came back from Africa (Angola) on 2nd June 2012. On 3rd June he started feeling ill. He got worse next days. The symptoms were strong headache, high fever, chills, delirium, vomit, couldn’t breathe and weakness. He went to hospital on 7th June. On 8th June was diagnosed with Malaria (Plasmodium Falciparum). Doctors induced him in a coma (10 days) so he could breathe through a machine. He got kidney’s failure, cardiovascular collapse (he needed to be reanimated) and severe anemia. Doctors thought he would die… He woke up from coma on 18th June. On 19th June he couldn’t see anything, it was all dark… First Doctors told us it was due to the quinine treatment, that when quinine come out from the blood he would recover vision. Later exams revealed optic nerve damages. Sometimes he sees images only during few seconds… Can you help us? Do you think this blindness is reversible? Is there any treatment we can do? Are you aware of cases like this? He has 35 years old, we are in panic… Thank you in advance.

ANSWER

I think I have answered this question within one of the comments sections on the website, but will briefly address it here as well. Your doctors are right – the blindness is probably a side effect of the intravenous quinine treatment, which likely saved your husband’s life, but the high dosage is also somewhat toxic to the body. Most patients do recover their vision eventually; one report which I read said that in the short term, treatment with charcoal derivatives can help to lower quinine levels in the blood, thus encouraging faster recovery.

Antimalarial Drugs During pPregnancy

by

QUESTION

What is the safest antimalarial drug to be used by a pregnant woman in her second trimester?

ANSWER

With regards to treating malaria, intravenous artesunate (or quinine, if artesunate is not available) should be used for the treatment of severe/complicated Plasmodium falciparum malaria. Signs of severe and/or complicated malaria include impaired consciousness, organ failure, abnormal bleeding, hypoglycemia, severe anemia and/or inability to ingest medication orally. Treatment for uncomplicated malaria (where the above signs are absent) in pregnant women is usually chloroquine for P. vivax, P. ovale, P. knowlesi and P. malariae, as well as for P. falciparum if there are no reports of this parasite being resistant to chloroquine in the area. In places where P. falciparum is resistant to chloroquine, quinine and clindamycin should be used to treat this parasite in pregnant women.

As for preventative anti-malarials (chemoprophylaxis), if a pregnant woman is travelling to an area where only P. vivax, P. ovale, P. knowlesi, P. malariae or chloroquine-sensitive P. falciparum is transmitted, then she should take chloroquine to prevent malaria. In areas where P. falciparum is resistant to chloroquine, mefloquine is also suitable during pregnancy. Note that in some areas of south-east Asia, there are areas where P. falciparum is resistant to mefloquine, which may prevent its suitability as a prophylactic in this region. Preventing malaria during pregnancy is crucial, since the mother, particularly if it is her first baby, is especially vulnerable to the parasite. Moreover, malaria can have a negative impact on the fetus.

Duration of Malaria Symptoms

by

QUESTION

If untreated how long will a person suffer symptoms caused by Malaria?

ANSWER

The answer to that depends a lot on what type of malaria they have as well as their own immune status, and particularly if they have been infected with malaria before. So, for example, P. falciparum is the most severe and deadly kind of malaria, and without treatment, many people who do not have acquired immunity (from previous infections) are likely to die within just a few days. This is the type of malaria that causes the most deaths, and explains why most of the fatalities occur in young children, who have not had the chance to acquire immunity.

In contrast, other kinds of malaria are less severe, and so symptoms can persist before the malaria parasite is naturally cleared by the parasite, usually within 1-2 weeks. In extreme cases, this can last much longer; Plasmodium malariae is the slowest replicating form of malaria, and so frequently causes mild infections which can last weeks, if not months. In some cases, people are infected with low levels of P. malariae for years without even experiencing symptoms, since their own immune system is able to keep levels of the parasite low enough so that they don’t cause noticeable disease.

Number of Species of Malaria

by

QUESTION

I recently read an ISOS world malaria day poster saying 5 species of plasmodium cause malaria. I think that is confusing as we always talked about 4, ovale, vivax, falciparum and malaria….are they referring to the way we now split ovale into 2 sub species? or is this a typo on their part?

ANSWER

That is a really interesting question, and a good observation on your part! I imagine the fifth species they are referring to is Plasmodium knowlesi, which is found in parts of south-east Asia, with the majority of cases being reported from Borneo. Originally known only from macaque monkeys, it appears to be occurring more frequently in humans. However, it is not known whether this is a new host switch, or whether it is simply a matter of better detection methods—the morphology of P. knowlesi closely resembles that of P. falciparum in its early trophozoite stages, and P. malariae in later trophozoite and other life stage forms. Moreover, some molecular-based tests for P. knowlesi cross-react with other forms of malaria, such as P. vivax, leading to greater diagnostic confusion.

There is also a hypothesis that changes in land use in tropical forests may be resulting in greater human exposure to the vectors which carry P. knowlesi, which accounts for its increased recent prevalence in humans. P. knowlesi is the only known malaria in humans (and indeed, in all primates) with a 24-hour reproductive cycle, which means that without treatment, high levels of parasitaemia can accumulate rapidly in the blood, and lead to severe clinical symptoms. This makes its apparent emergence of great public health concern in south-east Asia. Luckily, at this point, P. knowlesi is completely susceptible to chloroquine treatment and other medications, and so is easily controlled once diagnosed.

One of our contributors, Christina Faust, wrote a blog post last year on P. knowlesi entitled Of Macaques and Men. More information on recent research about P. knowlesi can be found in the article, Monkeys Provide Malaria Reservoir for Human Disease in South-East Asia.

Malaria Treatments

by

QUESTION

What are the of different types of antimalaria drugs?

ANSWER

Most drugs used in treatment are active against the parasite forms in the blood (the form that causes disease) and include:

  • chloroquine
  • atovaquone-proguanil (Malarone®)
  • artemether-lumefantrine (Coartem®)
  • artesunate-pyronaridine (Pyramax®)
  • dihydroartemisinin-piperaquine (Duo-Cotecxin®)
  • mefloquine (Lariam®)
  • quinine (given intravenously, this is recommended first-line treatment for severe, complicated malaria)
  • quinidine
  • doxycycline (used in combination with quinine)
  • clindamycin (used in combination with quinine)

All of the treatments above which combine an artemisinin-derivative (such as artemether, artesunate or dihydroartemisinin) in combination with another anti-malarial are called the artemisinin-based combination therapies (ACTs) and are collectively recommended by the World Health Organisation as the first line medication against uncomplicated malaria.

In addition, primaquine is active against the dormant parasite liver forms (hypnozoites) and prevents relapses. Primaquine should not be taken by pregnant women or by people who are deficient in G6PD (glucose-6-phosphate dehydrogenase). Patients should not take primaquine until a screening test has excluded G6PD deficiency.

Celebral Malaria and Blindness

by

QUESTION

I live in Nigeria. Good friend of mine complained of headaches in Dec 2011. Did an MRI went to Germany had a general check up. Back in Nigeria in January, headaches increase, she gets blind in one eye, following day the other eye, now in Germany where they have induced her into a coma. They said that she got a brain Haemorrage from the malaria. Can malaria bring blindness. What are the chances of surviving and getting back eyesight.

ANSWER

Although rare, brain hemorrhage is sometimes associated with severe cerebral malaria (caused by infection with Plasmodium falciparum, the most deadly form of malaria). This bleeding in the brain could cause blindness—whether the visual impairment is permanent or not depends on the extent of the bleeding and how much damage it caused.

I have found one case in the literature where severe malaria caused a brain hemorrhage which resulted in permanent blindness, and the authors report their case is only the second they have heard of, so this is rare indeed. Similarly, her survival will depend on how well she responds to treatment, which will likely be intravenous quinine, at least at first. Given that she is in Germany, where health care is excellent, I would say her chances are as good as they would be anywhere else in the world. I hope she makes a full and swift recovery!

Why not create a vaccine for malaria?

by

QUESTION

Why not create a vaccine for malaria?

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.

Another stumbling block has been inadequate financial commitment; increased resources devoted towards vaccine development would help overcome the scientific and technical obstacles in our way. PATH, coordinating the Malaria Vaccine Initiative, mentions for example that it can cost up to half a billion dollars ($500,000,000!) to fund a vaccine through the full process of development, testing and clinical trials through to licensing.

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.