Diagnosis
It can be difficult to clinically distinguish EVD from other infectious diseases such as malaria, typhoid fever and meningitis. Confirmation that symptoms are caused by Ebola virus infection are made using the following diagnostic methods:
• antibody-capture enzyme-linked immunosorbent assay (ELISA)
• antigen-capture detection tests
• serum neutralization test
• reverse transcriptase polymerase chain reaction (RT-PCR) assay
• electron microscopy
• virus isolation by cell culture.
Careful consideration should be given to the selection of diagnostic tests, which take into account technical specifications, disease incidence and prevalence, and social and medical implications of test results. It is strongly recommended that diagnostic tests, which have undergone an independent and international evaluation, be considered for use.
• Diagnostic tests evaluated through the WHO Emergency Use Assessment and Listing process Current WHO recommended tests include:
• Automated or semi-automated nucleic acid tests (NAT) for routine diagnostic management.
• Rapid antigen detection tests for use in remote settings where NATs are not readily available. These tests are recommended for screening purposes as part of surveillance activities, however reactive tests should be confirmed with NATs.
The preferred specimens for diagnosis include:
• Whole blood collected in ethylene diamine tetraacetic acid (EDTA) from live patients exhibiting symptoms.
• Oral fluid specimen stored in universal transport medium collected from deceased patients or when blood collection is not possible.
Samples collected from patients are an extreme biohazard risk; laboratory testing on nonactivated samples should be conducted under maximum biological containment conditions. All biological specimens should be packaged using the triple packaging system when transported nationally and internationally.
