The MERS coronavirus continues to simmer in the Middle East with the latest WHO EMRO report showing 118 cases reported (through Sept 30th) in 2018. Since 2012, 2260 conﬁrmed cases of MERS - including 803 fatalities - have been reported globally.
While MERS has yet to take off in a big way, it has proven itself to be more easily spread among humans than either of the two major avian flu viruses (H5N1, H7N9) we've been following for years.There are also legitimate questions over just how well surveillance systems are picking up infections, and the role - if any - of asymptomatic or mildly symptomatic cases in spreading the virus in the community.
Recently, in Evaluation of a Visual Triage for the Screening of MERS-CoV Patients - we looked at a review by prolific MERS researcher and former KSA Deputy Minister of Health, Ziad Memish, MD et al. of the visual triage & scoring system developed by the Saudis in 2017 to alert Health Care workers of possible MERS infection in their patients.
After evaluating the sensitivity and selectivity of this method, their conclusion:
The sensitivity and specificity of the scoring system was low and further refinement of the score is needed for better prediction of MERS-CoV infection.The authors were particularly blunt in their assessment (bolding mine) of the current system.
The current study conducted on a large number of patients shows that clinical scoring is not predictive of MERS infection.
Our results are robust and confirm that MERS cannot be distinguished from other respiratory infections based on risk factors and clinical features. Thus all patients with non-specific symptoms in a MERS endemic area will have to be isolated until MERS can be ruled out by rapid PCR testing.
In addition to seeing as steady stream of `community acquired' cases in KSA without a known risk exposure, we've seen other analyses that have concluded that only a fraction of MERS cases are likely diagnosed, including:
- In November of 2013, we looked at a study published in The Lancet Infectious Diseases, that estimated for every case identified, there are likely 5 to 10 that go undetected.
- In 2015, when Saudi Arabia had recorded fewer than 1200 MERS cases, a seroprevalence study (see Presence of Middle East respiratory syndrome coronavirus antibodies in Saudi Arabia: a nationwide, cross-sectional, serological study by Drosten & Memish et al.,) suggested nearly 45,000 might have been infected.
- And a 2016 study (see EID Journal: Estimation of Severe MERS Cases in the Middle East, 2012–2016) suggested that as much as 60% of severe Saudi MERS cases go undiagnosed.
I've excerpted a few passages from a much longer report. For more of the details on this case, you'll want to follow the link and read it in its entirety.
Atypical presentation of Middle East respiratory syndrome coronavirus in a Lebanese patient returning from Saudi Arabia
- Saeed El Zein American University of Beirut Medical Center, Beirut, Lebanon
- Jinane Khraibani American University of Beirut Medical Center, Beirut, Lebanon
- Nada Zahreddine American University of Beirut Medical Center, Beirut, Lebanon
- Rami Mahfouz American University of Beirut Medical Center, Beirut, Lebanon
- Nada Ghosn American University of Beirut Medical Center, Beirut, Lebanon
- Souha S Kanj American University of Beirut Medical Center, Beirut, Lebanon
Around 2090 confirmed cases of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) from 27 countries have been reported to the World Health Organization (WHO) between September 2012 and October 2017, the majority of whom occurring in countries in the Arabian Peninsula, mainly in Saudi Arabia.
MERS- CoV can have atypical and misleading presentations resulting in delays in diagnosis and is associated with a high mortality rate especially in elderly patients with multiple comorbidities.
Herein, we present the first case of confirmed MERS-CoV infection diagnosed at the American University of Beirut Medical Center (AUBMC) - Lebanon in June 2017 presenting without any respiratory symptoms. This is the second confirmed case of MERS-CoV infection in Lebanon since 2014. The first case presented with a febrile respiratory infection with persistent symptoms despite antibiotic treatment.
We report a case of MERS-CoV infection diagnosed in Lebanon, in a previously healthy patient resident of Riyadh, Kingdom of Saudi Arabia (KSA) presenting with fever and gastrointestinal symptoms.
The patient did not develop respiratory symptoms at any time throughout the course of the disease. To our knowledge, our case is the second documented case of MERS-CoV infection in Lebanon, and one of the few reported cases in the literature with complete absence of respiratory symptoms.
The patient is a 40-year-old male, previously healthy gastroenterologist, resident of Riyadh (KSA) for the past 5 years. On June 8, 2017 while still in Riyadh, he developed high grade fever, anorexia and fatigue. At that time, a nasopharyngeal swab for MERS- CoV by Polymerase Chain Reaction (PCR) was negative.
The patient had no contact with dromedary camels and did not drink camel milk. He also had no documented contact with any confirmed MERS-CoV patients and is not practicing in a hospital with known MERS-CoV cases.
However, he reported that he examined patients returning from Mekkah for Umrah several days prior to his illness. He failed to improve on a 7-day course of oral ciprofloxacin started on June 9. The patient reported taking a 5-day course of metronidazole started on June 11 after developing diarrhea.
There is still debate on the extent of infectivity of asymptomatic carriers of MERS-CoV . Ongoing viral shedding for 6 weeks has been detected by PCR from an asymptomatic healthcare worker .
Our patient, similar to many others reported in the literature, had no direct contact with a confirmed infected case suggesting that acquisition from an asymptomatic or mildly symptomatic carrier could be an important contribution to ongoing transmission [15,16].
Interestingly, 60 new cases of MERS-CoV infection were reported to the WHO in KSA between April 21 and June 10, 38 of which being from Riyadh , coinciding with the period in which our patient is thought to have acquired the infection.
MERS-CoV infection has a high fatality rate especially in elderly patients with multiple comorbidities. Human-to-Human transmission is well documented and asymptomatic carriers may play a big role in the transmission cycle. Our case proves that patients with confirmed MERS-CoV infection can have an atypical presentation with no respiratory symptoms making identification and adequate patient isolation a challenging task.
It is possible that MERS-CoV is underdiagnosed in patients with the above clinical picture. Therefore, it is very important to keep a high index of suspicion in all patients who present with fever of unclear etiology and have a direct epidemiological link to a MERS-CoV endemic area even with no history of exposure to a confirmed case within the past 14 days prior to presentation. Successful diagnosis will help in early isolation of the patient to prevent potential transmission to household members, travelers and healthcare workers and to avoid unnecessary antibiotics use.(Continue . . . )
While MERS-CoV hasn't embarked on a global tour the way that SARS did in 2003, we've seen analyses (see Study: A Pandemic Risk Assessment Of MERS-CoV In Saudi Arabia) suggesting the virus doesn't have all that far to evolve before it could pose a genuine global threat.
Earlier this year, in the WHO List Of Blueprint Priority Diseases, we saw MERS-CoV listed among the 8 disease threat in need of urgent accelerated research and development.
The second annual review occurred 6-7 February, 2018. Experts consider that given their potential to cause a public health emergency and the absence of efficacious drugs and/or vaccines, there is an urgent need for accelerated research and development for*:
- Crimean-Congo haemorrhagic fever (CCHF)
- Ebola virus disease and Marburg virus disease
- Lassa fever
- Middle East respiratory syndrome coronavirus (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS)
- Nipah and henipaviral diseases
- Rift Valley fever (RVF)
- Disease X
All of which makes gaining a better understanding of how - and how well - the MERS coronavirus continues to spread in the community a high priority.