US public health laboratories have responded quickly to detect the first US cases of MERS-CoV in Indiana and Florida. Public health labs across the country are prepared and ready to test for the virus.
The Illinois businessman who met with the Indiana MERS patient was not infected with MERS-CoV, according to an announcement by the CDC on May 28. The man, who had tested positive for MERS-CoV on an earlier serology test, tested negative on a more sensitive blood test.
Researchers continue to investigate whether asymptomatic or mildly ill patients can transmit MERS-CoV.
CDC and state health departments continue large-scale multistate investigations to control the spread of the virus. Efforts are underway to contact, test and monitor close contacts of the Illinois man.
CDC has moved quickly to apply newly-acquired
advanced molecular detection capabilities to the investigation of MERS-CoV cases. It now has complete genomic sequences from the MERS-CoV cases in Indiana and Florida. The sequences are available to researchers via GenBank.
For additional information, see the CDC
Case 2, Florida
A second imported case of MERS-CoV in the US was confirmed on May 11 by CDC and the Florida State Public Health Laboratory in Tampa. The patient, a 44 year-old male healthcare provider, resides and works in Saudi Arabia. This case is not linked to the first case of MERS-CoV detected in Indiana on May 1.
The patient traveled by plane from Jeddah, Saudi Arabia, to London, England, and from there to Boston, Atlanta and Orlando. He began feeling unwell on the flight from Jeddah to London and continued to feel unwell while en route with symptoms including fever, chills and a slight cough. He continued to experience symptoms upon arrival. On May 9 the patient went to the emergency department of the Dr. P. Phillips Hospital in Orlando where he was admitted the same day. He has since been discharged.
Case 1, Indiana
The first case of MERS-CoV was detected by the Indiana State Department of Health Laboratories May 1 and confirmed by the Centers for Disease Control and Prevention on May 2. Between May 3 and May 7, the Indiana state laboratory tested over 140 additional specimens from contacts of the patient. Public health laboratories in 15 other states have been involved in the investigation of patient contacts in their jurisdictions. The patient, a healthcare provider living and working in Saudi Arabia, has been released from the hospital.
On April 24, the patient departed Riyadh, Saudi Arabia and flew to Chicago, Illinois by way of London, arriving in Chicago. In Chicago, he took a bus to his final destination in Indiana. The patient experienced increasing fever and developed respiratory symptoms on April 27 and was admitted to an Indiana hospital on April 28.
Public Health Laboratory Capability
Forty-five public health laboratories – 44 state laboratories plus one large local laboratory – have the CDC real-time RT PCR test kit and have passed proficiency testing.
- Labs are to report all cases to CDC and forward specimens to CDC for confirmatory testing.
- Six states cannot conduct the test because they do not have one of the requisite extraction platforms (EasyMag or MagNA Pure) for the test.
- CDC will provide testing for suspect cases in states that do not have the assay available.
Test kits were deployed via the Laboratory Response Network (LRN) after the Emergency Use Authorization (EUA) was issued by FDA in June 2013. Again the LRN provided an effective mechanism for CDC test deployment.
Two types of laboratory tests are available for detecting infection with MERS-CoV:
The first is a MERS-CoV real-time reverse transcription polymerase chain reaction (real-time RT-PCR) assay that combines qualitative and quantitative measures to detect RNA expression levels in real time (i.e., qualitative and quantitative measurement is conducted simultaneously.) This test, which requires respiratory specimens, quantifies the number of copies of viral RNA per given volume of a specimen (generally measured in microliters). It is considered to be the optimal test for detection of RNA levels.
The second type are serology tests, which detect antibodies that indicate previous infection. Serology testing for for MERS-CoV includes three separate tests – (1) ELISA or enzyme-linked immunosorbent assay, (2) IFA or Immunofluorescent assay, and a third more definitive test called the neutralizing antibody assay. The neutralizing antibody test takes longer than the other two tests. These tests are conducted only at CDC.
Using the MERS-CoV real-time RT-PCR assay, public health laboratories continue to conduct testing for suspect cases of MERS according to CDC definitions of a
Patient Under Investigation.
- Health practitioners should forward specimens from patients who match the definition of a Patient Under Investigation (see link above).
- Epidemiologists and physicians should be on alert for the virus, particularly in travel hubs and areas with large Middle Eastern populations.
Resources for Public Health Laboratories
Note: The Emergency Use Authorization has been expanded to allow for testing of asymptomatic contacts.
2013 Coronavirus Emergency Use Authorization
Interim Laboratory Biosafety Guidelines for Handling and Processing Specimens Associated with Middle East Respiratory Syndrome Coronavirus (MERS-CoV)
Middle East Respiratory Syndrome (MERS) Information for Laboratories