CDC Now Provides Malaria Drug Resistance Testing Services
Starting June 1, 2012, CDC began offering malaria species confirmation and
malaria drug resistance testing services for cases of malaria diagnosed and
treated in the United States. These tests will be provided free of charge.
When resistance to a antimalarial drug reaches certain levels, the drug is no longer effective for prevention (in travelers) or treatment, and another must be used. Currently, only limited information is available about the emergence and spread of malaria drug resistance in many parts of the world.
CDC encourages all laboratories in the United States to make use of this service for all of the cases of malaria that they diagnose.
With information from drug resistance surveillance, CDC will be better able to formulate its prevention and treatment recommendations for those traveling from the United States to areas with malaria transmission.
CDC - Malaria
CDC - Malaria - Features - CDC Now Provides Malaria Drug Resistance Testing Services
Resistance to Antimalarial Drugs
In many places throughout the world, the malaria parasite has become resistant to the antimalarial drugs used to treat cases of malaria illness. First, resistance to chloroquine began to appear. This pattern then repeated itself with sulfadoxine-pyrimethamine, and now in some places in the Mekong region in Asia, some malaria illnesses have not been cured by artemisinin-containing antimalarial drugs.When resistance to a antimalarial drug reaches certain levels, the drug is no longer effective for prevention (in travelers) or treatment, and another must be used. Currently, only limited information is available about the emergence and spread of malaria drug resistance in many parts of the world.
New Surveillance Testing
To help address this gap, the CDC malaria and diagnostic laboratories will now offer expanded malaria testing services free of charge for all cases of malaria diagnosed in the United States---approximately 1,500 each year, virtually all of which were acquired in other countries. Services will include polymerase chain reaction (PCR)-confirmation of the species, identification of drug resistance mutations, and when possible, parasite culture for direct susceptibility testing.CDC encourages all laboratories in the United States to make use of this service for all of the cases of malaria that they diagnose.
With information from drug resistance surveillance, CDC will be better able to formulate its prevention and treatment recommendations for those traveling from the United States to areas with malaria transmission.
Diagnostic Testing
Drug resistance testing and parasite identification do not replace the initial diagnostic testing that must be performed immediately on site to diagnose a case of malaria. The gold standard for the diagnosis of malaria is microscopic visualization of Giemsa-stained parasites in a blood sample. The infecting species of malaria parasite is determined by the parasites’ morphological characteristics and the infected red blood cells. When microscopy services are not immediately available, an antigen detection test (also called rapid diagnostic test or RDT) may be used. Only after a diagnosis of malaria has been established should specimens be sent to CDC for assistance with determining the species or for drug resistance surveillance.
Likewise, treatment decisions and initiation of
therapy should occur immediately after the malaria diagnosis is made based on
the current treatment guidelines .
Clinicians should not wait for the results of the resistance testing to guide
therapy. Resistance testing results will likely require several weeks to be
completed.
Acceptable Specimens for Resistance Testing
Testing can be performed on multiple types of specimens including whole blood, dried blood spots on filter paper, as well as from fixed slides. Multiple types of specimens can be submitted if available, however the preferred specimen is whole blood (collected prior to receipt of antimalarial treatment medicines) in an EDTA blood tube. Specimens that arrive within 72 hours of collection are more likely to contain viable organisms for culture but older specimens can still be evaluated by PCR tests.
Specimens sent to CDC should be accompanied by the specimen
submission form. Additional information can be found in the instructions for
shipping specimens to CDC document.
- Instructions for shipping specimens to CDC [PDF, 1 page, 142 KB]
- Specimen submission form [PDF, 2 pages, 249 KB]
Malaria Resources for Health-Care Providers
Health-care providers are encouraged to use CDC
resources for malaria diagnosis and management advice. These include a Malaria
Hotline, which provides access to CDC malaria experts, web-based, continuously
updated information for clinicians on diagnosis and treatment of
malaria, and diagnostic assistance through DPDx.
CDC - Malaria - Features - CDC Now Provides Malaria Drug Resistance Testing Services
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