PRESENTOR:NURDEZA N PUNTUKAN

JAY G. CAYABSMT-4A

MALARIA

reference

The Diagnosis of Malaria by_Norman Moore, PhD_Director of Medical Affairs (ppt)

wikipedia

OBJECTIVES

To be able to know what is:1. Malaria2. Diagnostic test in determining malaria.3. Treatment4. Prevention

TABLE OF CONTENTS

MalariaVectorClassification of malariaSigns and symptomsDiagnosis

Malaria

Is a mosquito-borne infectious disease of human and other animals caused by parasitic protozoan's belonging to the genus plasmodium.

Malaria is one of the major causes of preventable death in the world today. It affects more than 500 million people worldwide and causes 1 to 2 million deaths every year.

Vector

The disease transmitted most commonly by an infected female anopheles mosquito.

The mosquito bite introduces the parasites from the mosquito saliva into a person blood.

The parasites travel to the liver where they mature and reproduce .Five species of plasmodium can infect and be spread by humans.

Classification of Malaria

Most deaths are caused by P.falciparum because P. vivax, P. ovale and P. malariae cause generally cause a milder form of malaria and the P.knowlesi rarely causes disease in humans.

Signs and symptoms

Diagnosis

The diagnosis of malaria may in fact into two ways :

Direct diagnosis: direct demonstration of the parasite whole cell or of parasite’s nucleic acid or products in the blood

Indirect Diagnosis: the demonstration of the patient’s immune response to the infection (immunodiagnosis).

(A) Light microscopic observation - Sample preparation 1- thin film observation of malaria parasites is

optimal when parasites are fixed and observed in their natural location within red blood cells after appropriate staining. This is best accomplished with the thin film preparation technique. Unfortunately, thin film has a low sensitivity and is thus inadequate for low parasitaemic infection.

2- thick film An adequate parasite concentration method is obtained by osmotic lysis of the red blood cells releasing the parasites, as is the case with the thick film preparation technique, the sensitivity is more than thin film.

- Fixation Its may be achieved by heat and alcoholic

solutions for 10-20 seconds . Methanol (methyl alcohol) is the most widely used fixative for malaria thin films.

- staining 1- Giemsa staining procedure Is the most commonly used method for both thin

and thick films all over the world for the quality of the stain and, of greater importance, because its stability in tropical climates.

2- Field staining procedure 3- Leishman staining procedure

Blood smear stained with Giemsa, showing a white blood cell (on left side) and several red blood cells, two of which are infected with Plasmodium falciparum (on right sideBlood smear stained with Giemsa, showing a white blood

- Field staining procedure. Field staining is a good method to stain thick films but is not suitable for thin films. However, it has the remarkable advantage to be extremely quick (the smear may be stained in 1 minute).

- Leishman staining procedure. Since Leishman staining solution uses methanol as a solvent, this method is only useful to stain thin films.

(B ) Quantitative Buffy Coat (QBC ®) and the direct acridine orange staining

Is a sensitive microscopic test based on the ability of acridine orange to stain nucleic acid containing cells

A direct acridine orange (fluorochrome) staining This method recently proposed of thin and thick film to provide an economically convenient alternative to the QBC ® technique for use in the field by using specially designed interference filters that may be connected to conventional light (even sunlight) microscopes

(C) DNA probes and Polymerase Chain Reaction

The initial studies in nucleic acid-based malaria diagnosis used the parasite’s repetitive DNA found throughout the Plasmodium genome as the diagnostic target . Therefore, after the sequencing of two small subunits (18S) rRNA genes from P. falciparum and P. vivax , species-specific regions of the rRNA genes have been exploited in developing a sensitive and specific

(D) Detection of P. falciparum antigen The production of histidine rich protein II

(HRP-II) antigen by blood stages of Plasmodium falciparum forms the basis for the development of ELISA antigen test and more recently, of the dipstick Becton Dickinson ParaSight ®-F test,

( E) Other direct diagnostic methods The determination of blood levels of parasite-

specific lactate dehydrogenase (pLDH) has been evaluated as indirect method of quantifying parasitaemia and also drug resistance

(D) Detection of P. falciparum antigen The production of histidine rich protein II

(HRP-II) antigen by blood stages of Plasmodium falciparum forms the basis for the development of ELISA antigen test and more recently, of the dipstick Becton Dickinson ParaSight ®-F test,

( E) Other direct diagnostic methods The determination of blood levels of parasite-

specific lactate dehydrogenase (pLDH) has been evaluated as indirect method of quantifying parasitaemia and also drug resistance

2- Indirect diagnosis (immunodiagnosis)

Detection of Plasmodia specific antibodies by:

1-Immunofluorescene (IFAT) The first serological test to be used for malaria antibodies was immunofluorescence (IFAT), which may give quantitative results for both G and M specific immunoglobulins. Its specificity and sensitivity largely rely on the laboratory technician’s expertise.

2- Indirect haemoagglutination test (IHA) : Is simple and suitable for field studies, but its sensitivity and specificity are poor

3- Radioimmunoassay (RIA) : is sometimes used but needs well equipped research laboratories and personnel.

Signs and symptoms

The sign and symptoms of malaria typically begin 8-25 days following infection, however symptoms may occur later in those who have taken antimalarial medication as prevention.

Treatment

Malaria is treated with antimalarial drugs and measures to control symptoms, including medications to control fever, antiseizure medications when needed, fluids and electrolytes. The type of medications that are used to treat malaria depends on the severity of the disease and the likelihood of chloroquine resistance. The drugs available to treat malaria include:

Chloroquine Quinine Hydroxychloroquine (Plaquenil) Artemether and lumefantrine (Coartem) Hydroxychloroquine (Plaquenil) Atovaquone (Mepron) Proguanil (sold as a generic) Mefloquine Clindamycin (Cleocin) Doxycycline.

PREVENTION

One way to prevent malaria is to avoid mosquito bites with the following strategies:

As much as possible, stay indoors in well-screened areas, especially at night when mosquitoes are most active.

Use mosquito nets and bed nets. It's best to treat the nets with the insect repellant permethrin.

Wear clothing that covers most of your body.Use an insect repellent that contains DEET or picaridin.

These repellents are applied directly to your skin, except around your mouth and eyes. If you choose a picaridin-based repellant, you will need to reapply it every several hours.

Apply permethrin to clothing.

Evaluation

1. what is the vector of malaria?2. What are the classification of malaria?3. What are the signs of malaria?4. What is the treatment of malaria?5. Prevention of malaria