Is it Malaria Relapse?

by

QUESTION

WHILE IN VIETNAM, I HAD VIVAX AND FACIPRIUM MALARIA. THE OLDER I GET I COME DOWN WITH THE CHILLS, FEVER AND PROFUSE SWEATING. BLOOD TEST NEVER DOES SHOW ANY MALARIA BUT DOES SHOW THE VIVAX ANTIBODIES. DOES THIS MEAN I STILL HAVE MALARIA OR HOW LONG DO THE ANTIBODIES REMAIN IN MY BODY AND WHY NO MALARIA CELLS?

ANSWER

Antibodies to malaria can persist in the body for years after the malaria infection, so if blood tests are not showing up malaria parasites but do show you have antibodies, then you probably don’t have malaria now, and it is just showing that you once had malaria, but it could have been many years ago. You should talk to your doctor about other possible infections that might be causing your symptoms.

Can the PCR blood test identify hypnozoites?

by

QUESTION

I have never been diagnosed with malaria but returned from Turkey in 2007 (P. Vivax endemic area; Diarbykar & Mardin areas). My symptoms were consistent with malaria and I have now had 5 relapses since then, averaging one occurrence per year. I now have impaired kidney functioning and I am uncertain if this could be because of undiagnosed malaria? Would the PCR blood test at anytime be an option to conclusively rule out malaria or would blood need to be drawn during an actual relapsing event?

ANSWER

You have certainly done your research! It’s great to hear from someone who is so well informed about the risk areas they traveled too and the diagnostic options. You’re right in thinking that PCR is only appropriate during an active relapse; while the malaria parasites are dormant in the liver (called hypnozoites, in that form), they are extremely hard to detect. One option could be to investigate the possibility of taking a test to look for antibodies to the P. vivax parasite. These tests are often referred to as ELISAs (enzyme-linked immunosorbent assays) and they can sometimes be useful for testing for malaria in between relapses because the antibodies your body produces against the malaria parasite during the relapse phase can stick around in the blood for weeks, or even months or years. Therefore these tests are not very useful for people in endemic areas (who may always have these antibodies, regardless of their current infection status) but for travelers who have been exposed a limited number of times, this test may be able to say whether you have at some stage been infected with P. vivax; together with your clinical history, this will provide strong evidence to your doctor that you might need to discuss the possibility of taking primaquine, the drug which can kill the dormant hypnozoites and prevent further relapse.

Testing for Dormant Malaria

by

QUESTION

When malaria is dormant in the body can it be detected in a blood test?

ANSWER

Not directly, no. A normal malaria blood test consists of a thick or thin smear, which is often stained and then looked at under a microscope; with these tests, you would not be able to see any sign of the malaria which is lying dormant in the liver. However, there is another type of blood test, known as serology, which looks for the body’s antibodies against malaria. These are proteins produced by the immune system when the patient becomes infected with malaria. These antibodies are specific to the type of malaria the person was infected with, and can persist for many months and even years. As such, if a patient was infected with one of the types of malaria which can become dormant (i.e. P. vivax and P. ovale), a serology test might be able to tell whether the patient had ever been infected with one of these two types, and then suggest that they might continue to have a dormant infection.

About Malaria Proteins

by

QUESTION

Please tell about about malarial causitive proteins.

ANSWER

I’m not sure what your question is, as malaria is not caused by a protein, but rather by a single-celled parasite called Plasmodium, which contains many different types of proteins. Some of these are indeed used for entering host cells and thus causing disease. Many of these proteins, and particularly ones on the surface of the malaria parasite, induce the host’s immune system, and so are called antigens. One of the most well known malaria antigens is called the Duffy antigen, and it is found on two types of malaria (Plasmodium knowlesi and Plasmodium vivax). It is used by the parasite to invade host red blood cells, and it is interesting because many populations of people in Africa have genetic changes in the parts of the red blood cell which the Duffy antigen binds to. This means these people, called Duffy negative, are much less susceptible to these types of malaria than people who are so-called Duffy positive and have normal red blood cells.

High Count of Malarial Antibodies

by

QUESTION

In 2007 we travelled to Kenya and Zanzibar. We took the normal anti-malarial tablets and were unaware of having been bitten. My older son has recently had a full medical and one of the blood tests which he had to repeat came back with a high count for malaria antibodies for Plasmodium falciparum. The doctor told him that he had had malaria at some time. We are puzzled as he has never been ill since returning. Can this happen? On the other hand my younger son has not been fully fit since returning from the trip, flu like symptoms, lack of energy etc. He has had several blood tests including one for glandular fever but nothing has shown up. Should he be tested for malarial antibodies? Could this be the reason he has had recurrent bouts of illness.

ANSWER

It is certainly possible to be exposed to malaria, but for your body to successfully fight the infection before it can reproduce and establish, thus the person will never experience the full illness. This is likely what happened with your elder son. As for your younger one, malaria tends to be an acute illness rather than a long-lasting chronic one, particularly the types of malaria that are found in East Africa.

Since your elder son was exposed and seems to have antibodies to malaria, I don’t think an antibody test will be particularly illuminating with regards to diagnosing your younger son. It would be better to have the doctors test him for malaria using the traditional thick and thin blood smears, which are then looked at under the microscope. This test will better inform the doctors whether your son has an active malaria infection, and will also be able to determine the species of malaria he has (if positive), and thus what treatment would be most effective for him. Again, though you should do this test to rule out malaria for sure, I think it is unlikely that your son has been experiencing symptoms caused by malaria for this length of time.

Persistent Antibodies to Malaria?

by

QUESTION

I had malaria as child, more than 30 years ago. It was successfully treated with no relapse. I have since travelled to malaria- endemic countries, but the last time was over 3 years ago. No symptoms. I recently donated blood and routine screening has detected malaria antibodies. How long do the antibodies persist?

ANSWER

Based on your experience, I would say at least three years! While I doubt your antibodies would persist since your infection as a child, it is more likely that in your more recent trips to malarial areas you have been re-exposed to the parasite, but for whatever reason, the infection didn’t progress into a full-blown episode of malaria. This could well be due to some residual immunity from childhood, or you just received a light enough infection that your general immune system was able to fight off. Either way, this would have produced new antibodies against malaria, which were picked up by the blood screen.

The length of time antibodies persist is important information in the control of malaria, since serological tests (which detect antibodies) can be used for screening of populations in low-transmission environments, but their efficacy is reduced in locations where people have been treated for malaria but their antibodies persist. Also, understanding how antibodies are created and maintained in the body is necessary for gaining an appreciation of how preventive measures, such as bednets, might potentially leave populations more vulnerable to malaria later on, through lack of acquired immunity.

Malaria and Pregnancy

by

QUESTION

Can your baby become immune if you’re pregnant and you have malaria?

ANSWER

Some of the protective antibodies that the mother produces when she has malaria can pass to her baby via the placenta. There is also evidence for immune system “priming” in foetuses when their mothers have been infected my malaria during pregnancy. However, these potentially protective effects are usually far outweighed by the negative effects of malaria during pregnancy.

Due to changes to the mother’s immune system and also perhaps due to the creation and physiology of the placenta, pregnant women are very vulnerable to malaria. For reasons which are not fully understood, women experiencing their first pregnancy (primagravidae) are most susceptible to malaria and their foetuses are most likely to have severe effects. These effects vary depending on the immune status of the mother and whether she is from an endemic or low transmission malaria environment, but typical results include low birth weight, anaemia and spontaneous abortion—abortion rates due to malaria can vary between 15-70%.

There is also the risk (up to 33% in some studies) that malaria will pass directly from the mother to the baby, either through the placenta or in blood during childbirth—this is called “congenital malaria,” and can manifest as early as 1 day after delivery but a late as months after. The symptoms are similar to that of adult malaria, with fever, anaemia, lethargy, etc.

Given these negative effects, it is very important to protect pregnant women against malaria, and bednet distribution schemes in many places target these women. In high transmission settings, women may also be offered intermittent preventive therapy (IPT) which consists of at least two doses of anti-malarial medication, usually once during the second and once during the third trimester.

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.

Late Malaria Confirmation

by

QUESTION

I was given a field diagnosis of malaria 1 1/2years ago and was treated. Can I still get a blood test to confirm if I truly had malaria?

ANSWER

That’s a very interesting question, and the answer is: it depends. Since you were treated, you will no longer have the parasites in your blood stream, and so you cannot use a traditional blood film, looked at under a microscrope, which is the standard diagnostic method in many places.

However, there are other blood tests which look for the presence of antibodies against specific malaria proteins. These antibodies can remain in the blood for a long time after the malaria infection – probably months, but perhaps even years, though the exact length of time may vary from person to person, as well as between antibodies. If you wanted, you could inquire in your hospital whether it would be possible to get a serology test for malaria (serology tests look for antibodies) – if they tell you the brand they use then you could also contact the manufacturer to ask if they have done tests on the length of time the antibodies stay in the blood.

Will Malaria Test Work with No Symptoms Present?

by

QUESTION

I believe my fiance who lives in Kenya has malaria but refuses to go for a test. She has headaches and now flu like symptoms. I am returning in late December, if the symptoms have gone can I still take her for a blood test to see if malaria is still present even if the symptoms subside?

ANSWER

Most malaria diagnosis in Kenya is done by looking at a small sample of the patient’s blood under the microscope. Unfortunately, using this method, it is almost impossible to detect malaria that is non-symptomatic. In this case, one option would be to use a rapid diagnostic test which looks for antibodies in the blood against malaria – as these antibodies can sometimes persist after the infection has subsided, it can sometimes tell you whether that person recently had malaria. These rapid diagnostic tests are available in most of the main cities in Kenya, in larger pharmacies, and maybe even in some big supermarkets like Nakumatt. However, given how rapidly malaria can progress and how serious is can become, I would highly recommend that your girlfriend goes to a clinic or doctor and has a malaria test! That way she can receive treatment early, before her symptoms get worse.