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close this bookBasic Malaria Microscopy (part I and II) (WHO - OMS, 1991, 72 p.)
View the document(introduction...)
View the documentPreface
View the documentIntroduction
View the documentLearning Unit 1. Malaria, the disease
View the documentLearning Unit 2. Cleaning and storing microscope slides
View the documentLearning Unit 3. Keeping accurate records
View the documentLearning Unit 4. Blood films
View the documentLearning Unit 5. Staining blood films with Giemsa stain
View the documentLearning Unit 6. The microscope
View the documentLearning Unit 7. Examining blood films
View the documentLearning Unit 8. Examining blood films for malaria parasites
View the documentLearning Unit 9. Artefacts in blood films
View the documentLearning Unit 10. Routine examination of blood films for malaria parasites
View the documentLearning Unit 11. Life cycle of the malaria parasite
View the documentLearning Unit 12. Supervisory aspects of malaria microscopy
View the documentBack Cover

Learning Unit 1. Malaria, the disease

Learning objectives

By the end of this Unit you should:

· recognize the importance of malaria as a disease
· be able to recognize the common clinical signs and symptoms of malaria
· know that some people can have malaria without clinical symptoms
· know that malaria is caused by the presence of parasites in a patient’s blood
· know that a female anopheline mosquito can transmit malaria to people
· realize that, to diagnose malaria accurately, you must be able to find and identify parasites in a stained blood film examined under the microscope.

The importance of malaria

Malaria is a serious public health problem in many parts of the world. Attacks of the disease can be very severe and can even lead to death if they remain untreated.

Malaria can be responsible for people spending many days away from school or work and so may affect:

· the amount that they learn at school
· the quantity of food they are able to grow
· the money they can earn.

Malaria is caused by a very small living organism called a parasite, which infects a person’s blood. The disease is transmitted from one infected person to another by the bite of a female anopheline mosquito. This can occur only after the parasite has been inside the mosquito for at least a week.

You will learn more about the malaria parasite and how the disease is transmitted in a later Learning Unit.

Clinical signs and symptoms of malaria

In people who have had very few attacks of malaria, the disease is fairly easy to recognize by the presence of one or more of the following clinical signs and symptoms:

· high fever
· headache
· severe chills
· general body pains.

In some cases the following symptoms are also present:

· vomiting
· diarrhoea.

As a learner, you may be confused because these signs and symptoms are also found in other diseases. Further observations are needed for accurate diagnosis.

It is more difficult to diagnose malaria in people who have had several attacks of the disease. This is because their bodies are more used to the disease and so the clinical signs and symptoms are not always present. Similarly, if patients have treated themselves with some medication before you see them, the signs and symptoms may be modified. A patient may have only a mild headache and nothing else, or a very slight fever that causes little discomfort.

How to diagnose malaria

Many people do not know that malaria is caused by a parasite in the blood. The parasite is very small and can be seen only with the aid of a microscope.

Before the parasite can be seen in a patient’s blood, a blood film must be made. The dry blood film is then stained with Giemsa stain and examined under the microscope, using the oil immersion objective lens. If stained parasites are seen by the examiner, the patient is confirmed as having malaria.

You should therefore understand that the only correct way to diagnose a case of malaria is by examining the patient’s stained blood film with a microscope. This is a highly skilled job. The following Units of this Learner’s Guide will take you through the steps necessary to acquire the skills you need.