Sunday, September 28, 2014

Ebola Opinion: What do you do when you can't tell those with Ebola from patients with other conditions?

Distinguishing Ebola cases from others is the most immediate need for health care providers and patients.  If you cannot determine immediately who is infected, patients with other conditions will be lumped with possible Ebola patients, and may contract Ebola as a result of healthcare!

Even worse (from the point of view of medical providers) is that nurses and doctors will not know for which patients extreme personal protection measures are needed.  Dr. Brantly felt he was exposed to Ebola not in the Ebola ward, but when caring for patients in other areas who had not been diagnosed with Ebola, but had it and were spreading it, while they were believed to have a different problem.

What is the solution?  Reverse transcriptase PCR is used currently.  It requires fancy equipment, plenty of training and a clean lab.  This is not a test that can be performed in the bush.  Immunoassays can also be done, but are not suitable for early detection nor use in rural communities.

According to UpToDate:

Virus is generally detectable by RT-PCR between 3 and 10 days after the onset of symptoms [1]. The demonstration of genetic diversity and rapid accumulation of sequence changes of Ebola virus in the West African epidemic indicates that careful monitoring will be needed to ensure the continued sensitivity of RT-PCR diagnostics [2]. Antigen detection may be used as a confirmatory test for immediate diagnosis [3].
In some cases, testing for IgM or IgG antibodies to Ebola virus may also be useful to monitor the immune response over time and/or evaluate for past infection.

What is needed to deal with Ebola at the village level is a test that could be performed in rural clinics, such as a urine antigen test, and it would need to detect low levels of antigen for earlier, asymptomatic detection. Preferably, the test would employ a card, with a spot that changes color when Ebola virus antigen is detected. Serious consideration should be given to developing rectal and saliva Ebola antigen tests as well.

Were such a test available, it could be performed daily on patients so, as soon as patients began to excrete even low levels of virus, they would be moved to an isolation facility. Testing patients for Ebola just once, using any current method, will miss some number of cases, and those missed cases could infect their families and medical personnel.

Until Ebola can be quickly identified and non-Ebola patients are safely managed (away from all Ebola patients) the healthcare systems in Ebola-ravaged countries will remain crippled.
  1. The Centers for Disease Control and Prevention. Interim Guidance for specimen collection, transport, testing, and submission for Patients with Suspected Infection with Ebola Virus.Disease lab-guidance.pdf (Accessed on August 25, 2014).
  2. Gire SK, Goba A, Andersen KG, et al. Genomic surveillance elucidates Ebola virus origin and transmission during the 2014 outbreak.
  3. Feldmann H. Ebola - A Growing Threat? N Engl J Med 2014.

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