Malaria....

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Transcript of Malaria....

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Malaria - is a vector-borne infectious disease

caused by protozoan parasites. It is widespread in tropical and subtropical regions, including parts of the Americas, Asia, and Africa

- it is one of the most common infectious diseases and an enormous public health problem. The disease is caused by protozoan parasites of the genus Plasmodium.

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Infective Female Anopheles Mosquitothe only mosquitoes can transmit

malaria, and they must have been infected through a previous blood meal taken on an infected person.

When a mosquito bites an infected person, a small amount of blood is taken, which contains microscopic malaria parasites.

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Symptoms: fever shivering arthralgia (joint pain) vomiting anemia (caused by hemolysis) hemoglobinuria retinal damage convulsions

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A. Plasmodium vivax- causes Benign Tertian Malaria- most endemic in the world- relapsing/recurrent- prefer young RBC`S- Erythrocytic cycle: 48 hours- serrated/fimbriated- stippling/granulations: Schuffner`s dots

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B. Plasmodium ovale- causes Ovale Malaria- also prefer young RBC`s- Erythrocytic cycle: 48 hours- relapsing- enlarged RBC- stippling/granulations: Schuffner's

C. Plasmodium Knowlesi - primate malaria

- different to distinguish from P. Malariae, microscopically

- Erythrocytic cycle: 24 hour- Shot gun appearance

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D. Plasmodium falciparum- causes Malignant Tertian Malaria / Aestivo-autumnal Malaria/ Black

fever- present in all ages of RBC`s- causative agent of Malaria- Erythrocytic cycle: 36 hours- marginal accole/applique forms- stippling/granulations: Maurer`s

dots

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E. Plasmodium malariae- causes Quartan Malaria - prefer older RBC`s- Erythrocytic cycle: 72 hours/3

days- rosette, flower, fruit pie or daisy

head- stippling/granulations: Zeiman`s

dots

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Duffy negative people Delayed transfusion reaction

Glucose-6- phosphate dehydrogenase deficiency

Hemoglobinopathies Change in the hemoglobin molecule in

RBC`S Sickle Cell anemia

A anemia caused by a hemoglobin defects that results in irregularly shaped red blood cells. It is an inherited disorder.

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Sporozoites infect liver cells and mature into schizonts , which rupture and release merozoites. (Of note, in P. vivax and P. ovale a dormant stage [hypnozoites] can persist in the liver and cause relapses by invading the bloodstream weeks, or even years later.)  After this initial replication in the liver (exo-erythrocytic schizogony ), the parasites undergo asexual multiplication in the erythrocytes (erythrocytic schizogony ). Merozoites infect red blood cells. The ring stage trophozoite.

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The gametocytes, male (microgametocytes) and female (macrogametocytes), are ingested by an Anopheles mosquito during a blood meal. The parasites’ multiplication in the mosquito is known as the sporogonic cycle. While in the mosquito's stomach, the microgametes penetrate the macrogametes generating zygotes.The zygotes in turn become motile and elongated (ookinetes) which invade the midgut wall of the mosquito where they develop into oocysts.The oocysts grow, rupture, and release sporozoites , which make their way to the mosquito's salivary glands.  Inoculation of the sporozoites into a new human host perpetuates the malaria life cycle.

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Cerebral Malaria Parasite blocks blood vessels, decreased

oxygen supply to tissue leading to death/ Tissue anoxia.

Causes organ failure/specifically renal failure

Black water fever sudden intravascular hemolysis leading to

hemoglobinuria. Malarial Fever

Fever that accompanies an infection is the result of macrophage derived cytokines acting on the brain.

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Thick Blood FilmRapid screening

test for the presence of malaria species

Dehemoglobinized RBC

Old blood is not advisable

Thin Blood FilmFor specie

identificationGeimsa is the

preferred stain to use

Don`t use blood with anticoagulant (distorts the parasite and alter staining)

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is a new method for identifying the malarial parasite in the peripheral blood.

It involves staining of the centrifuged and compressed red cell layer with acridine orange and its examination under UV light source.

It is fast, easy and claimed to be more sensitive than the traditional thick smear examination.

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new kit method technique. The stick detects the Plasmodium protein or parasite-specific Lactate Dehydrogenase (pLDH) present in P.falciparum infection.

This method is a rapid and accurate method for detection of P. falciparum infection.

It uses monoclonal antibodies to detect PLDH

Present in a finger prick sample Principle: Immunochromatograpic assay

(dipstick)

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Principle: antigen capture immunoassay, immunochromatography

Antigens detected: HRP2 and pLDH Sensitive  

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Positive control pLDH HRP2

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Positive control pLDH HRP2

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is used to detect antibodies against plasmodium. Due to presence of antibodies for long period in the blood

it is not of practical routine diagnostic test for malaria, but it may be useful for:- Screening of blood donors prior to blood transfusion to avoid transmission of infection.- To monitor the prognosis of the disease and evaluation of treatment method.

Principle: Indirect hemeagglutination

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