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Communicable Diseases Module: 7. Diagnosis of Malaria

Study Session 7  Diagnosis of Malaria

Introduction

In this study session you will learn about two different methods used to identify malaria parasites in patients (parasite-based tests). But first you will need to make a clinical or ‘presumptive’ diagnosis of malaria, based on recognising the most common signs and symptoms of the disease, including severe malaria.

The most important malaria diagnostic method used at the community level is the rapid diagnostic test (RDT) for malaria. RDTs provide a quick way to tell whether a person with malaria-like symptoms actually has malaria, as the test takes only 15–20 minutes. The RDT detects certain chemicals in the blood that are produced by malaria parasites if they are present. In this study session you will learn how to use the RDT kit for malaria, including the precautions you must take when performing an RDT, and how to interpret the results.

Finally, we will briefly describe how malaria can be diagnosed using microscopic techniques to detect the presence of parasites in blood smears. You are not expected to use a microscope for diagnosis, but it is useful for you to know what is involved in microscopic diagnosis, which is done at health centres and hospitals.

Learning Outcomes for Study Session 7

When you have studied this session, you should be able to:

7.1  Define and use correctly all of the key words printed in bold. (SAQ 7.1)

7.2  Describe how to diagnose malaria and assess the severity of cases, based on clinical signs and symptoms. (SAQs 7.2 and 7.3)

7.3  List the advantages and limitations of rapid diagnostic tests (RDTs) for malaria. (SAQ 7.4)

7.4  Explain how to perform RDTs for malaria safely and effectively, and record the results accurately. (SAQs 7.5 and 7.6)

7.5  Explain how microscopic examination is used to diagnose malaria and state its advantages over RDTs. (SAQ 7.7)

7.1  Clinical diagnosis

In Study Session 2, you learned how to classify and diagnose communicable diseases according to their clinical symptoms. In this section, you will be able to apply those principles to the clinical diagnosis of malaria. In Study Session 5 you learned that some members of the population, such as children under the age of five years and pregnant women, are at a higher risk of getting malaria due to their weaker immunity. By learning how to identify malaria with clinical diagnosis (and confirm it with RDTs) you will be able to provide effective and prompt treatment of malaria to patients at the community level. By identifying signs and symptoms of severe malaria, you will also be able to refer patients that need higher medical care to the health centre or hospital. In this way your knowledge and actions could save many lives, as poorly diagnosed and managed malaria could kill many people in your community.

7.1.1  The symptoms and signs of malaria

The clinical symptoms of malaria vary from very mild to very severe, depending on several factors. In areas where malaria is very common, adults with the disease may show just a slight increase in body temperature. However, pregnant women, and in particular, young children, often have a severe illness with many symptoms. The most important symptom of malaria is fever (or a history of fever within the last two to three days). An attack often begins with shivering (body shaking). This is followed by a period of fever, and finally there is profuse sweating. During an attack the patient often complains of headache and pains in the back, joints, and all over the body (Figure 7.1).

A sick man lying in a bed at home.
Figure 7.1  An adult with malaria, Ethiopia.

There may also be loss of appetite, vomiting, and diarrhoea. The patient may feel better the next day, but may have another attack the day after that, and so on. If untreated (or inadequately treated), malaria can cause several weeks or months of poor health because of repeated attacks of fever, anaemia (see Box 7.1) and general weakness. Some patients rapidly become very ill and may die within a few days.

Box 7.1  Anaemia

Anaemia means not enough haemoglobin in the blood. Haemoglobin is the red substance in the red blood cells which carries oxygen. Malaria parasites destroy the red blood cells and so malaria may cause anaemia. Anaemia may also have other causes (for example, not enough iron in the food). You can recognise anaemia by looking at the patient’s hands: the palms of a person with anaemia do not have the redness of a healthy person’s palms. If the red colour of the inner eyelid or mouth is paler than in a healthy person, the patient has anaemia. Breathlessness and a fast pulse may also be present, because the person’s blood cannot carry enough oxygen for their needs.

A critical feature that may help you to recognise if a fever is due to malaria or not is that malarial fever occurs in cycles – periods of fever alternate with periods in which the patient shows normal body temperature (below 37.5°C) and no symptoms. The stages of malarial fever attacks are shown in Table 7.1. (You will learn more about how to identify malaria cases in Section 7.2.3).

Table 7.1  Clinical symptoms of a typical malarial fever attack.
Stage of malarial fever attack
Stage nameCold stage Hot stageSweating stage

Main clinical symptoms

  • Feeling very cold
  • Vigorous shivering
  • Feeling very hot – higher than normal temperature
  • Dry burning skin
  • Headache
  • A lot of sweating
  • Fall in temperature
  • Feeling exhausted and weak
  • Tendency to fall asleep
How long symptoms last15–60 minutes2–6 hours2–4 hours
  • A four-year-old patient is presented to you with fever of 38°C. The child also has poor appetite, is weak and has yellowish eyes. What other questions should you ask his mother or guardian to try and find out if the child is suffering from malaria? Give reasons for your answer.

  • You should try to find out how long the child has had fever. You should also find out whether the fever has alternated with a stage of sweating, followed by a cold, shivering stage. A child with a fever could have malaria, but fever can also be a symptom of other diseases. However, a child who has gone through stages of fever, sweating and shivering is much more likely to be suffering from malaria, as this is the typical pattern of malarial fever attacks.

Malarial fever attacks usually repeat every 48 hours, for patients infected with the two most common species of plasmodium in Ethiopia, P. vivax and P. falciparum.

7.1.2  Course of malarial disease

Symptoms of malaria usually start to appear 7 to 21 days after the bite of an infected mosquito. However, the normal incubation period is different for different species of Plasmodium, as described in Study Session 5. Remember that the incubation period is the time between the parasite getting into the blood of a person and the onset of symptoms.

  • Can you recall, from what you learned in Study Session 5, which of the following malaria parasites has the shortest incubation period? Which has the longest?

    • Plasmodium falciparum
    • Plasmodium vivax
    • Plasmodium malariae
    • Plasmodium ovale.
  • P. falciparum has the shortest and P. malariae has the longest incubation period.

A patient who is not treated may develop severe complications and may die, or may continue to have cycles of fever alternating with symptom-free periods. In general, the more Plasmodium parasites there are in the blood, the more severe the disease will be.

Disease progression varies with the parasite species

Disease progression varies according to the species of Plasmodium that has infected the patient. Patients infected with P. vivax, especially for the first time, can be quite ill. However, P. vivax rarely causes complications or results in death. Relapses (return of malaria symptoms due to activation of an old infection) due to P. vivax can occur for several years.

Patients with serious complications are generally referred to a health centre; you will learn how to refer such patients in Study Session 8.

By contrast, P. falciparum is the most lethal form of malaria infection. It causes the most serious complications, which are anaemia (Box 7.1 above) and cerebral malaria. In cerebral malaria, red blood cells infected by the parasite stick to small blood vessels in the brain. This reduces the flow of blood and the supply of oxygen and nutrients to the brain. If untreated, cerebral malaria can kill the patient in 24–48 hours. It most commonly affects young children (Figure 7.2).

A mother holds her sick child.
Figure 7.2  A mother with a child suffering a malaria attack. (Photo: UNICEF Ethiopia)

7.1.3  How you can identify cases of malaria

The most important element in the clinical diagnosis of malaria is for you to be alert and to suspect malaria in all patients with fever, whether your catchment area is located in a malarious area or not. Because the distribution of malaria in Ethiopia is patchy, it is also very important for you to find out the geographical and travel history of a patient who shows signs and symptoms of malaria, most importantly fever.

In non-malarious areas, you should suspect malaria in a patient who has high fever, or has had fever in the last 48 hours, if the person has travelled to a malarious area or country in the previous two weeks. In malarious areas, fever, or a history of fever in the last 48 hours, should be enough for you to suspect malaria in a patient. You should pay particular attention to children under the age of five years and pregnant mothers, as these groups are at a higher risk than others.

  • Why do you think children are at higher risk of getting severely ill or dying of malaria than adults?

  • Children have a much weaker immunity against malaria. Immunity develops after repeated exposures to the malaria parasite and this takes time.

You can recognise malaria by asking the right questions and looking for the important signs (see Box 7.2):

Box 7.2  How to approach a clinical diagnosis of malaria
  • Ask: Ask questions and listen to what the patient has to say (if the patient is a young child, listen to the parent or guardian). If the patient (or parent) does not mention fever, ask whether there has been a fever at any time during the past 2–3 days. Patients who have had fever during the last 2–3 days may have malaria.
  • Look: Examine the patient for symptoms of malaria. Measure the temperature with a thermometer. If the temperature is more than 37°C, the patient has a fever. (If you do not have a thermometer with you, feel the forehead with the back of your hand. If the forehead feels hot, the patient probably has a fever).
  • Check: In addition to fever, malaria patients can show the following signs and symptoms: loss of appetite, refusal to breastfeed (child), weakness, nausea, vomiting, headache, joint pains, muscle aches. If you see any of these features you should think about malaria and act immediately. If there is no fever and no history of fever during the past 2–3 days, the patient does not have malaria.

7.1.4  Danger signs of severe malaria

If the patient has had fever during the past 2–3 days, first ask about and then look for danger signs:

Ask:

  • Is the patient unable to drink?
  • Has the patient had convulsions (fits)?
  • Does the patient vomit repeatedly?
  • How much urine does the patient pass? Very little? None at all? Is it dark?
  • Is the patient breathing fast, or having difficulty breathing?
  • Does the patient have yellowish eyes, mouth or palms?

Look:

  • Is the patient abnormally sleepy, difficult to wake, or confused?
  • Does the patient have anaemia?
  • Does the patient have severe dehydration? (Look for sudden weight loss, loose skin, sunken eyes, dry mouth)
  • Is the patient unable to stand or sit?
  • Is the patient breathing fast, or having difficulty breathing?
  • Does the patient have yellowish eyes, mouth or palms?

Important!If the answer to any of these questions is yes, the patient has severe malaria. The patient’s life is in danger. Urgent treatment is needed to save the patient’s life so refer immediately to the nearest health centre.

7.2  Parasitological diagnosis of malaria

If you suspect that a patient may have malaria, you will need to confirm the clinical diagnosis using specific tests to identify the presence of the malaria parasite or its products in the blood. This process is called parasitological or parasite-based diagnosis. In areas with a risk of malaria, or in patients who have travelled back from malaria-endemic areas, fever should be enough to make you suspect malaria and do a confirmatory test. The parasitological diagnosis of malaria can be divided into microscopic and non-microscopic tests. Microscopic tests involve the use of a microscope to see the parasite in the blood of a patient. At health post level you will not be able to carry out microscope tests, but they will be discussed briefly in Section 7.2.3. First we describe the non-microscopic tests, also known as rapid diagnostic tests (RDTs).

7.2.1  Introduction to rapid diagnostic tests (RDTs) for malaria

The national malaria diagnosis policy in Ethiopia is that Health Extension Workers and Practitioners must test anyone suspected of having malaria by using the RDT for malaria. RDTs are now available in all health posts in areas where malaria is a risk and you will receive some practical training in how to use them.

The Ethiopian national guidelines state that malaria treatment at health post level, or referral from the health post to the health centre, should be based on RDT test results, so knowing how to use the RDT properly is a very important part of your job. In this section you will learn how to use the RDTs more effectively. You will also learn about the precautions you have to take to protect yourself and other patients when working with blood.

How RDTs work

RDTs test whether a person with malaria-like symptoms actually has malaria by testing the blood of the patient for chemical substances produced by malaria parasites. Malaria parasites produce proteins called antigens. RDTs detect malaria antigens, so if they are present, the person will test positive. If malaria antigens are not present, the person will test negative.

The reason for using RDTs

RDTs enable you to find out if a fever is really caused by malaria rather than by other illnesses. You can also get information about which malaria parasites may be causing the infection. The information provided by RDTs is important for three main reasons:

  • First, being able to tell quickly whether a patient with fever has malaria or not ensures that the patient can receive the correct treatment.
  • Second, if a patient does have malaria, knowing which parasite may be involved is important, as some malaria parasites are more dangerous than others and require more urgent treatment.
  • Can you remember which malaria parasite causes the most serious malaria in Ethiopia?

  • P. falciparum can kill a person in 24–48 hours, for example by causing cerebral malaria. P. vivax is less likely to cause complications and is rarely fatal.

You will learn about malaria case management with these drugs in Study Session 8.

  • Third, falciparum malaria treatment in Ethiopia is based on artemisinin combination therapy (ACT), which is more expensive than older anti-malarial drugs such as chloroquine (CQ) and sulfadoxine-pyrimethamine (SP). Vivax malaria accounts for 40% of the malaria cases in Ethiopia, but it does not need treatment with ACT. By identifying which patients have falciparum malaria, RDTs can save money, as ACTs will then only be given to patients with falciparum malaria.

By using the RDT you will be able to test for malaria parasites in a patient’s blood, and in this way to provide a more accurate diagnosis than a clinical or presumptive diagnosis. RDTs give results in about 15–20 minutes, so a patient with malaria can begin treatment right away. RDTs do not require any expensive or complicated equipment and can be used by you in the patient’s home. You should be able to learn to use RDTs in just a few hours in your practical training programme.

Limitations of RDTs

RDTs are very effective for diagnosing malaria, but there are some things they cannot do.

First, RDTs cannot test how many malaria parasites there are in the blood – they can only test whether parasites are present or absent. In fact, RDTs do not detect actual parasites; they detect parasite antigens, as mentioned above. Some parasite antigens can remain in the blood for at least two weeks after the parasites have been killed by drugs.

  • What will be the result if an RDT is used on a person within two weeks of taking anti-malarial drugs, and should you trust the result? Explain your answer.

  • An RDT used within two weeks of drug treatment may still detect parasite antigens and so give a positive result for malaria infection, even if the person no longer has parasites, because the parasites have been killed by the drugs. This is why this positive result cannot be trusted.

Second, RDTs can be damaged by heat and humidity, so the RDT should not be removed from its sealed package before you are ready to use it. If a package has been open for some time before the RDT is used, the RDT may be damaged and can give an invalid (false) result. You should discard this package and use another, unopened, package.

Actions following positive and negative results from RDTs

The national malaria treatment guidelines now recommend the use of parasite-based diagnosis using RDTs for malaria by community health workers for all age groups, except when the RDT is not available due to logistics problems.

  • Before using the RDT, ask the patient if he or she has recently taken anti-malaria medication. If the patient has taken a complete course of anti-malaria medication in the last 5–14 days, a positive RDT result may be misleading (see above). It may be necessary to refer the patient to a health centre with a laboratory for further testing using a microscope.
  • If fever persists a few days after a negative RDT result and other appropriate management has been applied, you should re-test the patient with another RDT, as RDTs can sometimes miss early malaria infections.

Otherwise:

  • If the patient has not recently taken anti-malarial medication and the test result is positive, treat the person for malaria according to national guidelines (see Study Session 8).
  • If a patient has fever and the second test result is still negative, refer them to a higher level health centre.

We now explain how to use an RDT, and how to interpret the results.

7.2.2  How to use an RDT to get a malaria test result

Here is the checklist that you must follow when you are using an RDT for malaria diagnosis.

(i) Check the expiry date on the package. Do not use RDTs that have expired.

(ii) Put on gloves before beginning (Figure 7.3). Use a new pair of gloves for each patient. Do not re-use gloves.

Gloves being put on.
Figure 7.3  Put on new gloves before starting each RDT. (Source: WHO, 2006, see marginal note)

Figures 7.3 to 7.10 are from WHO, 2006, How to Use a Malaria Rapid Diagnostic Test (RDT): A Guide for Training CHWs and Other Health Workers.

(iii) Open the RDT package and remove the contents. The blood-transfer device — it could be a capillary tube, straw, loop, pipette or other device — is used to collect blood and transfer it to the test cassette. (Once the packet is opened, the ‘desiccant’ sachet which absorbs moisture from the atmosphere in the package should be discarded.) The test cassette (shown later, in Figure 7.8) is used to conduct the test. The square hole labeled ‘A’ is where you add the blood. The round hole labeled ‘B’ is where you add the buffer.

(iv) Write the patient’s name on the cassette (Figure 7.4).

A hand holding a pencil and writing on the cassette.
Figure 7.4  Write the patient’s name on the cassette.

(v) Open the alcohol swab and clean the patient’s third or fourth finger with alcohol (Figure 7.5). This is to prevent infection. Other fingers may be used if necessary. Ask the patient: ‘Are you right-handed or left-handed?’ If the patient is right-handed, choose a finger on their left hand. If the patient is left-handed, choose a finger on their right hand.

A patients finger being cleaned.
Figure 7.5  Clean the patient’s finger with alcohol.

(vi) After cleaning the finger with the alcohol swab, the finger must be allowed to air dry. After using the alcohol swab, place it on its wrapper and set it aside on the table. You will use it again to stop the bleeding after you collect the patient’s blood.

(vii) Once the patient’s finger is dry, open the lancet. Prick the patient’s finger, preferably towards the side of the pulp (ball) of the finger. Discard the lancet in a sharps-only container immediately after using it (Figure 7.6).

Important!Never put the lancet down before discarding it. Never discard the lancet in a non-sharps container. Never use a lancet on more than one person.

The lancet being put in a ‘sharps only’ safety box.
Figure 7.6  The lancet used in the RDT must be put in a ‘sharps only’ safety box.

(viii) Turn the ‘patient’s’ arm so their palm is facing downward. Squeeze the pricked finger and allow a drop to well up below the finger tip as in Figure 7.7. Use the loop or capillary tube or straw or the pipette to collect the drop from underneath. Once you have collected a sufficient amount of blood, you may hand the alcohol swab back to the patient and show him or her how to use it to stop the bleeding.

Blood being drawn from the finger using a capillary tube.
Figure 7.7  Drawing blood with a capillary tube.

(ix) Use the device (capillary tube, straw, loop, pipette or other) to add the drop of blood to the sample window (square hole labeled with the letter A, see Figure 7.8). The blood needs to reach and be absorbed by the pad at the base of the square hole. If the blood is mostly deposited on the plastic edges of the well, but does not reach the pad, the test will not work correctly. Deposit the blood in the correct place using the capillary tube, straw, loop, pipette or other. Adding too much or too little blood can cause the test to give an invalid result or be difficult to read.

Blood being added to the RDT cassette.
Figure 7.8  Adding blood to the RDT cassette.

(x) Add the buffer solution to the round hole labeled B. Hold the bottle vertically when adding the buffer solution, as in Figure 7.9. This ensures the correct drop size.

The buffer solution being added to the RDT cassette.
Figure 7.9  Adding the buffer solution.

(xi) Wait for the correct duration of time (15 or 20 minutes) after adding buffer before reading the test results.

(xii) Discard the blood-collection device (e.g. capillary tube) safely after use.

(xiii) Remove and discard your gloves at this time. To avoid possible contamination, the used gloves should be discarded in the non-sharps container before you do anything else.

7.2.3  How to read and interpret an RDT test result

The different possible results and what they mean are illustrated in Figure 7.10 and summarised in Table 7.2.

The different possible test results of a malaria RDT.
Figure 7.10  The different possible test results of a malaria RDT. ‘C’ is the control line; ‘T1’ and ‘T2’ are the test lines.

Table 7.2  Malaria RDT interpretation chart.

As you can see from Figure 7.10 and Table 7.2, sometimes the result can be invalid, that is, it could be incorrect.

  • What should you do if the test result is invalid?

  • Discard the RDT cassette. Open a new cassette and repeat the test using the new cassette.

7.2.4  Microscopic test for malaria

Malaria parasites being viewed under a microscope.
Figure 7.11  Malaria parasites being viewed under a microscope. (Photo: I-TECH/Julia Sherburne)

Microscopic diagnosis of malaria is done by a trained laboratory technician at health centre or hospital level. It is not your responsibility to do a microscope test, but this section will briefly explain it so you understand the technique.

Microscopic diagnosis involves taking a small amount of blood from the patient, staining it and looking at it under a microscope to check for malaria parasites. In most cases of malaria, microscopic examination of thick and thin films of finger-prick blood will reveal malaria parasites. Thick films are 20–40 times more sensitive than thin films for detecting Plasmodium parasites, and are particularly useful if the number of parasites is low. Thin smears are also useful as they can allow identification of particular Plasmodium species (Figure 7.11). The diagnostic accuracy relies on the quality of the blood smear and the experience of laboratory personnel.

Summary of Study Session 7

In Study Session 7, you have learned that:

  1. Knowledge of the signs and symptoms of malaria is important for its clinical diagnosis.
  2. Different species of the malaria parasite can cause malaria of different severity. Of the two species present in Ethiopia, P. falciparum is more likely to cause a severe and fatal disease. Young children and pregnant women are more at risk of serious infection as they have weaker immunity.
  3. The most important clinical symptom of malaria is fever (or a history of fever within the last 2–3 days), typically with regular attacks every 2–3 days lasting several hours. Attacks often begin with shivering, followed by fever, then profuse sweating.
  4. In areas where malaria incidence is low, always ask those who have a fever about their travel history to malaria endemic areas in the last two weeks.
  5. Carefully observe all suspected or confirmed malaria cases for any signs of severe malaria, which include convulsions, anaemia, repeated vomiting, high fever (above 39°C), severe dehydration, drowsiness or confusion, and reduced urine output.
  6. Refer severe cases immediately.
  7. Whenever possible malaria treatment should be based on parasitological diagnosis of malaria rather than on a clinical diagnosis based on symptoms.
  8. Rapid diagnostic tests (RDTs) for malaria are available at health post level and are effective in diagnosing malaria if correctly used. RDTs cannot distinguish between species of malaria parasites or estimate the number present in the patient’s blood sample.
  9. In the absence of RDTs, you will need to use clinical symptoms to diagnose malaria. In some cases you may need to refer patients to the health centre or hospital, so a microscopic diagnosis of malaria can be carried out to confirm malarial infection.

Self-Assessment Questions (SAQs) for Study Session 7

Now that you have completed this study session, you can assess how well you have achieved its Learning Outcomes by answering these questions. Write your answers in your Study Diary and discuss them with your Tutor at the next Study Support Meeting. You can check your answers with the Notes on the Self-Assessment Questions at the end of this Module.

SAQ 7.1 (tests Learning Outcome 7.1)

What method is available to you at health post level to allow you to make a parasite-based diagnosis of malaria?

Answer

The RDT or Rapid Diagnostic Test for malaria is available at health post level.

SAQ 7.2 (tests Learning Outcome 7.2)

Malaria is rare in your village. However, a 25 year-old male comes to your health post complaining of loss of appetite and muscle aches. You suspect malaria, but you don’t have an RDT kit to confirm your diagnosis. What questions should you ask him to either exclude malaria as a possible diagnosis, or decide that you should treat him for malaria?

Answer

You would ask him about his travel history to malaria-endemic areas in the last two weeks. You would also ask him if he has had fever in the last two to three days.

SAQ 7.3 (tests Learning Outcome 7.2)

A five-year-old child comes to your health post with fever. He was tested with an RDT and the result was positive for falciparum malaria. Before treating and sending him home, you have to check for signs of severe malaria in case he needs a referral. What are the signs and symptoms you would look for?

Answer

The danger signs of severe malaria are anaemia, convulsions, repeated vomiting, high fever (>39˚C), shivering, sweating, severe dehydration, drowsiness or confusion, and reduced urine output.

SAQ 7.4 (tests Learning Outcome 7.3)

You have learned that RDT and microscopy are two simple and useful methods to diagnose malaria. List two important advantages of RDT over microscopy.

Answer
  • The RDT is simpler than microscopy and can be easily handled at health post level, whereas microscopy tests can only be done at a health centre.
  • RDT results are ready within 15–20 minutes, whereas microscopy tests may take much longer as the patient has to go to the health centre.

SAQ 7.5 (tests Learning Outcome 7.4)

You are confronted with more than 20 fever cases in the community around your health post at the same time. You will test all patients with RDTs for malaria. What do you do to avoid any mix-up of results?

Answer

Write each patient’s name on the RDT cassette to avoid mixing-up the results if you have to do several tests at the same time.

SAQ 7.6 (tests Learning Outcome 7.4)

List the precautions you need to take to avoid contaminating yourself and your patients with another person’s blood, when performing an RDT for malaria.

Answer
  • Wear gloves when handling blood from patients.
  • Use one pair of gloves for each patient.
  • Swab the patient’s finger with alcohol before and after pricking it with the lancet.
  • Use one lancet for each patient.
  • Dispose of the lancet and gloves safely immediately after use.

SAQ 7.7 (tests Learning Outcome 7.5)

You treated the five-year-old child positive for falciparum malaria in SAQ 7.3, according to the national guideline. The child comes back after three days with fever and you again test him with an RDT. The patient was again positive for falciparum malaria.

  • a.What will be your next action?
  • b.What are the advantages of microscopy over RDTs?
Answer
  • a.Refer the child to the health centre for microscopic examination of his blood; RDT positive results after three days of anti-malaria treatment are not reliable, because RDTs can give a positive test up to two weeks after treatment.
  • b.The advantages of microscopy over RDT are:
    • Microscopy can tell you if parasites are cleared and a patient is cured immediately after anti-malarial treatment.
    • Microscopy can tell you the number of parasites in the patient’s blood; a high number of parasites could mean a high risk of developing severe complicated malaria.