This week, the WHO was notified of the first confirmed case of Middle East Respiratory Syndrome (MERS) in 2018. That this notification was made in the midst of two other significant health security threats—the Ebola outbreak in the Democratic Republic of the Congo (DRC) and an Nipah outbreak in India—is a good reminder of the importance of building strong public health and healthcare capacities and of investing in robust, scalable emergency response systems. Specifically, though, it also speaks to the need for public health to maintain operational partnerships with the healthcare sector to improve detection and response to such outbreaks. Below, we will review the recent case of MERS and highlight commonalities among outbreak responses to MERS, Ebola, and Nipah.
What is known about the latest MERS case?
According to the WHO, a 78-year-old man with fever, cough, and shortness of breath presented to a hospital in Abu Dhabi, UAE on May 13. Clinical specimens collected on May 14 tested positive for MERS-CoV infection, and UAE’s International Health Regulations (IHRs) National Focal Point reported the laboratory-confirmed case to the WHO on May 16. The patient is in stable condition, but he has also been diagnosed with hypertension and interstitial lung disease. The presence of underlying comorbidities has been reported in the literature as being positively associated with patients’ development of severe disease and death, although it is unclear to what degree specific comorbidities increase these risks.
MERS is a viral respiratory disease caused by a coronavirus that was first identified in Saudi Arabia in 2012. While 80% of reported cases have occurred in Saudi Arabia, 27 other countries have reported sporadic MERS cases. Evidence indicates that dromedary camels serve as the primary animal reservoir, and zoonotic transmission is believed to occur via contact with contaminated animal products, particularly raw camel milk, camel urine, or undercooked camel meat. Limited human-to-human transmission has been documented, the majority of which has occurred in the healthcare environment.
This latest case from the UAE brings the global total of laboratory-confirmed MERS cases to 2,207 since its discovery in 2012—787 of which have died. According to the WHO, the notification of the new MERS case “does not change the overall risk assessment,” and they continue to expect that cases of MERS will occur in the Middle East as well as other countries due to disease exportation.
While the occurrence of a single new MERS case is not cause for global alarm, it is prudent for health authorities to monitor the situation to ensure that further transmission does not occur. In 2015, a single imported case of MERS in South Korea initiated a hospital-associated outbreak that resulted in 186 cases and 36 deaths. Preventing such outbreaks from occurring in the UAE or elsewhere will require adherence to proper infection control practices, identification and investigation of those who had contact with the patient, and continued surveillance and testing of patients with similar symptoms and risk factors.
What Do MERS, Ebola, and Nipah Have in Common?
While the viruses that cause MERS, Ebola, and Nipah are morphologically unreleated and their diseases are clinically quite different, there are similarities in the response to associated outbreaks. For example, while outbreaks involving sustained community transmission of Nipah and MERS occur far less frequently than for Ebola, all three have exhibited the potential for nosocomial transmission. During the 2013-16 Ebola epidemic in West Africa, health workers were between 21 and 32 times more likely to be infected with Ebolavirus than the general population. During the 2015 South Korea MERS outbreak, more than 90% of cases were among health workers, other caregivers, and other hospital patients. Additionally, the remaining cases included hospital visitors and security personnel who were also likely infected in a healthcare setting. For another large MERS outbreak in Jeddah, Saudi Arabia, 97.3% of cases were determined to be healthcare-associated infections and a third of the cases were among health workers. Data regarding nosocomial transmission of Nipah are a bit less certain, but in a 2001 outbreak of Nipah in India, more than 50% of cases occurred among health workers and visitors to a hospital that treated a Nipah-infected patient. Additionally, epidemiological studies have found that prior close contact with a Nipah patient, such as being involved in direct care of an infected individual, is common among cases. One study, however, found low risk of transmission to healthcare workers treating Nipah patients, even with poor PPE compliance. In the current Nipah outbreak in India, news sources are reporting that several health workers may be among the 15 cases reported to date.
Another commonality of Ebola, MERS, and Nipah outbreaks is the important role that frontline health workers can play in the initial identification of cases that can lead to early detection of an outbreak. In the current Nipah outbreak, clinicians at Baby Memorial Hospital are credited with contributing to the early detection of the outbreak by promptly diagnosing Nipah in the first known case of the outbreak. These efforts enabled health authorities to rapidly initiate a public health response, including an evaluation of the patient’s contacts for Nipah virus infection. Conversely, in the current Ebola outbreak, the first cases likely occurred at least one month before the outbreak was detected by public health authorities, by which point the infection had been transmitted to dozens of others. To date, there have been 53 reported cases of Ebola (36 confirmed) and 26 deaths.
While MERS, Nipah, and Ebola may differ significantly in their taxonomy and clinical presentation, the similarities in response highlight the continued need for better infection control practices and enhanced disease surveillance in healthcare settings. By improving these capacities, healthcare facilities can enhance their outbreak response to a variety of pathogens, thus decreasing the potential for disease transmission and subsequently saving lives. Considerable international attention and resources are being dedicated to containing the Ebola outbreak in the DRC, including the implementation of critical vaccination efforts and clinical trials, but the current situations in UAE and India highlight the importance of maintaining the capacity to combat a variety of simultaneous health threats on multiple fronts.
Photo: World Health Organization Headquarters in Geneva, Switzerland.
Outbreak Observatory aims to collect information on challenges and solutions associated with outbreak response and share it broadly to allow others to learn from these experiences in order to improve global outbreak response capabilities.