Diagnosis (Microscopy)
Migrant workers clinic at Mawker Tai camp in Thailand near the Myanmar border. Microscopy plays a critical role in diagnosis of malaria, one of the major health problems in this area. Image contributed by the Shoklo Malaria Research Unit, Mae Sot, Thailand.
Microscopic examination remains the "gold standard" for laboratory confirmation of malaria in the malaria-endemic world, as well as in the United States.
Technique
A blood specimen collected from the patient is spread as a thick or thin blood smear, stained with a Romanovsky stain (most often Giemsa), and examined with a 100X oil immersion objective. Visual criteria are used to detect malaria parasites and to differentiate (when possible) the various species. (See DPDx specimen preparation) (See DPDx Plasmodium species comparison chart.)
Advantages and Disadvantages
Advantages: Microscopy is an established, relatively simple technique that is familiar to most laboratorians in endemic countries. In such areas, microscopy is a standard technique used for diagnosing other diseases (such as tuberculosis), often by the same laboratorians using the same facilities and equipment.
Disadvantages: In many developing countries, microscopy is not reliable because the microscopists are often insufficiently trained and supervised and are frequently overworked, the microscopes and reagents are of poor quality, and often the supply of electricity is unreliable.
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Atlanta, GA 30333 - Health care providers needing assistance with diagnosis or management of suspected cases of malaria should call the CDC Malaria Hotline:
770-488-7788 or 855-856-4713 toll-free
(M-F, 9am-5pm, eastern time). - Emergency consultation after hours, call:
770-488-7100
and request to speak with a CDC Malaria Branch clinician. - malaria@cdc.gov
