The details of how a single patient in an overcrowded emergency room transmitted the MERS virus to 82 individuals in South Korea in just three days were released recently. The data maps the case of highest transmission of the virus from a single patient outside of the Middle Eastern region till date.

The researchers who studied and formulated the map suggest that there is a possible potential of future MERS-CoV spread and “healthcare facilities worldwide need to be prepared for emerging infectious diseases”.

Middle East respiratory syndrome coronavirus (MERSCoV) was first identified in a corpse of a 68-year-old man from Saudi Arabia, who died of multi-organ failure and pneumonia in September 2012. The virus infection shows symptoms like shortness of breath, cough, and fever. Nearly three to four patients out of 10 have died after acquiring this infection. In cases where death occurs, other underlying medical conditions have been identified as contributing factors.

Since the start, the virus has spread to 27 countries including South Korea. Within two months of the outbreak, 186 cases of the viral infection have been confirmed in South Korea.

The transmission map shows that patient 1 (index patient), who had visited four Middle Eastern countries between April and May 2015, was the point of outbreak origin. The man visited United Arab Emirates, Bahrain, Qatar and Saudi Arabia. He visited the Samsung Medical Center in Seoul on May 17 and was isolated the next day on suspicion of MERS virus. He was officially diagnosed on May 20.

However, he had already spread the virus to several other individuals in other healthcare facilities before arriving to the Samsung Medical Center. One such case, a 35-years-old man (patient 14) with whom the index patient had shared a ward, was an important point of transmission.

It was patient 14 who was admitted to Samsung Medical Center later on May 27, without any possible indication of the virus, that spread the disease and caused the outbreak at the Center. The exposure caused infections in 33 patients, eight healthcare workers and 41 visitors.

1,576 people were exposed to patient 14, and 285 patients and 193 healthcare workers were exposed to patient 1, according to the review of closed-circuit security video footage and electronic medical records from the hospital. The researchers suggest that the difference in exposure and transmission could be due to multiple factors such as symptoms, duration, pattern of movement, spread of virus itself and onset of disease.

Professor David S Hui from the Department of Medicine and Therapeutics and Stanley Ho Center for Emerging Infectious Diseases, the Chinese University of Hong Kong, China, commented that overcrowding in the emergency room could be one of the contributing factors to this super spreading event.

The contributing researchers Professor Doo Ryeon Chung and Yae-Jean Kim, Division of Infectious Diseases at the Samsung Medical Center, Seoul, South Korea, agreed and said, “Overcrowding is an important issue for this outbreak but also a common feature of modern medicine which should be of concern to governments and healthcare providers in the context of future possible outbreaks.”

They suggested that emergency preparedness and vigilance should be important part of the outbreak prevention strategies at hospitals, laboratories, and government agencies not only of MERS-CoV infections, but also other emerging infectious diseases.

There is growing evidence that increased bed occupancy rates and overcrowding influence the spread of hospital-acquired infections (HAIs). These infections are the most frequent adverse events seen in healthcare delivery and the burden caused by these diseases is often complicated by antimicrobial resistance.

Only two cases of MERS have been reported in US, that too before June 2014. Continued monitoring efforts ensure that foreign travelers do not bring the virus back to the country. However, any infectious disease like pneumonia can potentially turn deadly in healthcare facilities if not controlled properly. According to the CDC, there were 722,000 HAIs in acute care hospitals which resulted in 75,000 deaths in the year 2011.

The latest US outbreak of HAI was seen in September 2012, and is currently under investigation by the CDC in collaboration with the FDA, state and local health departments. The case count reached 753 and resulted in deaths of 64 individuals. The outbreak spread over 20 states with multiple points of origin. The multistate outbreak of meningitis and other infections was seen among patients who received contaminated MPA steroid injections from the New England Compounding Center in Framingham, Massachusetts.

The most common US outbreak seen is of norovirus which causes diarrhea and vomiting once acquired. Severe diarrhea can have fatal consequences. Nearly 61% of cases are caused due to direct contact and three out of four cases occur in long term care facilities.