49 Ebola False-Alarms in the USA Since 2018
Ebola testing with OraQuick Ebola Rapid Antigen Testing explained
A new Health Advisory was published by the Alert Network Network (HAN) with updated guidance regarding the usage of a new rapid diagnostic test (RDT) for detecting the Ebola virus in symptomatic patients.
Published by the HAN on December 16, 2019, this Centers for Disease Control and Prevention (CDC) Health Advisory (#432) says ‘healthcare providers caring for a patient with possible Ebola virus infection should first contact their local or state public health authorities before any testing is performed.’
Furthermore, ‘RDTs should be used only in cases where more sensitive molecular testing is not available.’
And, ‘the interpretation of RDT results should be done with caution and in consultation with relevant public health authorities to ensure appropriate testing and interpretation of results.’
In Health Advisory #423, the CDC says ‘there have been 49 travelers since August 2018 who were ill when returning to the USA from the Democratic Republic of Congo (DRC) or the surrounding African countries.
Of these 49 individuals, testing for Ebola was recommended for just 1 person.
The good news from the CDC is that person tested negative for Ebola and was subsequently treated for malaria.
In the USA, presumptive testing for the Ebola virus (Zaire ebolavirus) is now available at 69 Laboratory Response Network (LRN) laboratories located in 49 states, which are accessible through coordination with state or local public health authorities.
These laboratories may be needed in the future.
As of December 17, 2019, more than 3,348 confirmed Ebola Zaire cases and about 2,210 related fatalities have been confirmed during the ongoing central Africa outbreak centered in the DRC.
Despite concerns, Ebola may spread into additional countries, such as Uganda and Rwanda, the CDC now says that the ‘risk of Ebola infection for most U.S.-based travelers in Africa is low.’
And, ‘the risk of global spread of Ebola to the USA and elsewhere is also low.’
‘Only those going to the outbreak area or who otherwise have contact with an Ebola-infected person (living or deceased) are at risk. Family and friends caring for people with Ebola and healthcare workers who do not use correct infection control precautions, are at higher risk.’ says the CDC in the Health Alert.
Furthermore, it is possible for Ebola to spread through sex or other contact with the semen of a man who has recovered from Ebola.
This longer-term contamination risk is because the Ebola virus can remain in certain body fluids of people who have recovered from Ebola. These body fluids include semen, fluids in the eye, and fluids found around the brain and spine.
However, even with a low-risk, the Ebola virus has proven it can reach the USA, then spread.
During the 2014-16 Ebola outbreak in Africa, 11 patients with Ebola were treated in the USA. Four of these patients became ill after they arrived in the USA, either after exposure in West Africa or in a healthcare setting.
Three of these Ebola cases were confirmed in Dallas, Texas.
Two nurses who cared for the sick patient contracted Ebola, marking ‘the first known transmission in the United States,’ says the Texas Department of State Health Services.
Both infected nurses recovered, but unfortunately, the patient died.
And on December 29, 2018, an American providing medical assistance in the DRC experienced a possible exposure to the Ebola virus and was flown to Omaha, Nebraska for monitoring.
“This person may have been exposed to the virus but is not ill and is not contagious,” said Ted Cieslak M.D., associate professor of epidemiology at the University of Nebraska Medical Center College of Public Health, in a press release.
On January 12, 2019, this individual never developed the potentially deadly Ebola disease and posed no risk to the public and was successfully discharged.
The CDC’s new Health Alert recommends that Ebola virus testing be conducted only for people who have an epidemiologic risk factor within 21 days of symptom onset and who have an Ebola compatible clinical syndrome.
And, the CDC published usage recommendations regarding the U.S. Food and Drug Administration (FDA) approved OraQuick® Ebola Rapid Antigen Test.
These RDT results are ‘presumptive, which means all test results (positive and negative) must be verified through real-time reverse transcriptase-polymerase chain reaction (rRT-PCR) testing.’
State public health authorities or healthcare facilities in the USA considering integrating the OraQuick® Ebola Rapid Antigen Test into their Ebola testing algorithms or preparedness protocols should consider the following recommendations:
- The RDT should be used only in circumstances where more sensitive molecular testing is not available.
- RDTs should be used only in collaboration and consultation with relevant public health authorities to ensure appropriate testing and interpretation of results.
- All results (positive and negative) from the OraQuick® Ebola Rapid Antigen Test are presumptive and must be verified through rRT-PCR testing that is available at 69 LRN laboratories located in 49 states and at CDC. Testing at LRN laboratories is coordinated through state or local public health authorities.
- Per existing protocols, specimens that test positive by the Ebola virus rRT-PCR assay at an LRN laboratory must be forwarded to CDC for confirmatory testing.
- Negative RDT results alone should not be used to rule out Ebola virus infection or to determine the use or type of infection prevention and control precautions when managing a patient with compatible symptoms and epidemiologic risk factors.
- The OraQuick® Ebola Rapid Antigen Test may result in false-positive results in patients that have elevated rheumatoid factor levels.
- Additionally, potential cross-reactivity of the test with Ebola vaccines or therapeutics is possible and has not been evaluated, and patients who have received vaccines or therapeutics against Ebola virus may have false positive or other confounding results.
- It is important to consult with public health authorities prior to the use of RDTs and to aid in the interpretation of RDT results.
- Facilities that collect and handle specimens from patients with suspected cases of Ebola should ensure adequate biosafety protocols are in place for the handling and disposal of all potentially infectious materials to avoid the risk of inadvertent exposure.
- For healthcare providers collecting specimens, appropriate personal protective equipment should be used.
The OraQuick® Ebola Rapid Antigen Test has shown to be capable of detecting antigens for three Ebolavirus: Zaire ebolavirus, Bundibugyo ebolavirus, and Sudan ebolavirus, however, the test cannot differentiate between species, says the FDA.
Molecular testing at CDC is available to confirm these results and is also required to differentiate between species of Ebolavirus.
The Ebola virus disease is a rare and deadly disease caused by infection with viruses within the genus Ebolavirus.
There are four known species within the genus Ebolavirus that are known to cause disease in humans: Ebola virus, Sudan virus, Bundibugyo virus, and Taï Forest virus.
People can become infected through contact with blood or body fluids of a person infected with or who has died of Ebola. Ebola virus can also be spread through contact with contaminated objects or infected animals.
The signs and symptoms of Ebola are non-specific, both in the early and advanced clinical course.
Symptoms of Ebola can include fever, headache, muscle and joint pain, abdominal pain, weakness and fatigue, gastrointestinal symptoms including diarrhea and vomiting, and bleeding or bruising.
Because most travelers are at low to no risk of becoming infected with Ebola, other more common differentials with similar clinical symptomatology such as malaria, dengue, influenza, or typhoid should be considered.
Healthcare providers interested in testing for the Ebola virus in ill returning travelers should isolate the patient and contact their state or local public health authorities. An assessment of epidemiologic risk factors for Ebola and clinical presentation and history should be made as quickly as possible to ensure patient care is not compromised.
The CDC is available to provide consultation, technical assistance, and confirmatory testing as necessary.
Recently, there has been good news announced regarding Ebola preventive vaccines and therapeutic treatments, such as:
- Rwanda’s Umurinzi Ebola Vaccine Program Launches
- Just 2 Ebola Medicines Found Safe and Effective
- Japan Begins Ebola Vaccine Candidate Tests
Travel vaccine and medication news published by Vax-Before-Travel.