Malaria IdentificationIt is easier than you think!

Susan Flaker Johnson, MT(ASCP), MEPD

Malaria Identification The learner will be able to:

Describe the symptoms of Malaria

Determine areas of the world where Malaria is endemic

Identify Malaria parasites within red blood cells

Identify the species of Malaria present within red blood cells

What is Malaria?

Italian for “Mala Aria” or Bad Air

It was thought to be caused by breathing stale, warm, humid air found around swamps

It is the Mosquitoes, not the Bad Air

Why Malaria? 3.3 billion people live in areas at risk for Malaria WHO estimates that in 2008 Malaria caused 190

- 331 million clinical episodes and nearly 1 million deaths

89% of those who die are in Sub Saharan Africa, and the majority of those are children

It is the 5th leading cause of death from infectious diseases worldwide (after respiratory infections, HIV/AIDS, diarrheal diseases, and tuberculosis)

It has increased in the last three decades

http://www.cdc.gov/malaria/about/facts.html

Malaria in the Western Hemisphere

http://wwwnc.cdc.gov/travel/yellowbook/2010/chapter-2/malaria.aspx

Malaria in the Eastern Hemisphere

http://wwwnc.cdc.gov/travel/yellowbook/2010/chapter-2/malaria.aspx

Malaria in the USA Anopheles mosquitoes are found in the USA ~ 1500 cases are reported every year 1st and 2nd generation Americans returning to

their “home” countries are less likely to take prophylactic medication

1957 – 2009, 63 outbreaks of locally transmitted Malaria have occurred

1963 – 2009, 96 cases of transfusion-transmitted Malaria were reported

http://www.cdc.gov/malaria/about/facts.html

Malaria in the USA

http://www.cdc.gov/malaria/features/2008_us_data.html

Common Symptoms of Uncomplicated Malaria FEVER 100%

Chills Headache Nausea and Vomiting Myalgia

Thrombocytopenia Anemia Splenomegaly Hepatomegaly

Symptoms of Severe Malaria Seizures, impairment of consciousness, coma Severe anemia Hemoglobinuria Acute respiratory distress syndrome (ARDS) Coagulopathies Acute kidney failure Low blood pressure caused by cardiovascular

collapse

Diagnosis of Malaria Patient Symptoms and Physical Findings Patient History

Foreign Travel? Blood Transfusion?

Laboratory Testing Rapid Diagnostic Tests

False Negatives with low parasitemiaInsufficient data on P. ovale and P. malariaeCDC recommends all positives be followed up with Microscopy

PCR – Available through WSLH and CDCConfirmatory, but there is a delay

Microscopy – ConfirmatoryNeed for competent laboratory professionals

http://www.cdc.gov/malaria/diagnosis_treatment/rdt.html

Specimen Requirements for Microscopy

FRESH EDTA whole blood

Thick and Thin Blood Smears – made within ONE hour

Giemsa stain is preferred

Wright’s Stain is OK for thin smears

Malaria Cycles

SPECIES NAME RBC CYCLE PAROXYSM

CYCLE

P. vivax Benign Tertian 45 hours 8 – 12 hours

P. ovale Tertian 48 hours 8 – 12 hours

P. malariae Quartian 72 hours 8 – 10 hours

P. falciparum Malignant Tertian 48 hours 16 – 36 hours

Species Distribution

Plasmodium vivax 50%

Plasmodium falciparum 43%

Plasmodium malariae 7%

Plasmodium ovale 2%

Plasmodium vivax

Plasmodia in enlarged RBCs (retciulocytes)

Plasmodia in RBCs with Schuffner’s dots

Plasmodia with more than 12 chromatin masses

(usually 16 – 24)

Trophozoite tends to be amoeboid

Plasmodium vivax

Plasmodium malariae

Plasmodia in RBCs of normal size, usually in aging cells

Plasmodia in band stage

Plasmodia rarely have more than 12 chromatin masses (usually 6 – 12) and in a rosette

No Schuffner’s dots

Plasmodium malariae

Plasmodium ovale

Relatively rare

Infected RBCs tend to be oval or burred and of normal size or in reticulocytes (slightly larger RBCs)

Plasmodia with 8 chromatin masses (usually 6 – 10)

Schuffner’s dots may be present

Plasmodium ovale

Plasmodium falciparum Plasmodia in the crescent (banana shape) stage

Plasmodia in ring stage with 2 chromatin dots

Plasmodia in RBCs in eclipse (accole) position

More than one ring (trophozoite) per RBC

Intermediate stages rarely seen, all plasmodia in film in

ring stage or gametocyte stage, but not both

Plasmodia invade all stages of RBCs

Plasmodium falciparum

Now for the Test…..

http://www.rph.wa.gov.au/malaria.html

Other Organisms to Consider

Plasmodium knowlesi

Babesia microti

Plasmodium knowlesi Emerging New Form of Malaria Monkey Malaria Found in South East Asia

Malaysia Borneo Thailand – Burma border region Philippines Singapore

24 hour reproductive cycle Potentially fatal

Plasmodium knowlesi Appearance in blood films similar to P malaria

http://www.cdc.gov/eid/content/15/9/1478-F1.htm

Plasmodium knowlesi

Diagnosis Blood film screening – appears similar to P

malariae Compact parasite – all stages Does not alter RBCs size Schizonts 8 – 10 merozoites, arranged in a rosette

Rapid Diagnostic Tests may NOT recognize P knowlesi

PCR – most reliable

Babesia microti

Tick transmitted Found in USA

Upper Midwest Wisconsin

May be confused with P falciparum

Babesia microti

Diagnosis Microscopy – Thick and Thin Blood Films

Small, delicate parasites Multiple organisms within a single RBC Tetrads within a single RBC

Antibody detection by indirect fluorescent antibody (IFA)

Molecular Methods - PCR

Babesia microti

http://www.dpd.cdc.gov/DPDX/HTML/Babesiosis.htm