coronavirus

Introduction

Coronavirus (CoV) is an enveloped positive sense single stranded RNA virus located in the coronaviridae family. This group of viruses is found throughout the world and can cause a variety of diseases in humans and animals such as domestic pets. Human CoV circulates within the human population, often as ‘the common cold’, whereas bats are believed to be the reservoir for most zoonotic coronaviruses.

Epidemiology

Human CoV typically cause a low level of annual lower and upper respiratory tract infections. It causes approximately 25% of common colds with only rhinovirus causing more cases. While infection often results in upper and/or lower respiratory tract infections, evidences suggests it may be an important diarrhoeal disease in developing countries. The virus is spread through droplet transmission. The main routes of transmission between humans is through the air by inhalation of droplet particles, or close contact. These droplet particles can be propelled up to 3 feet by a cough or sneeze. The droplet particles containing the virus can land on surfaces and inanimate objects forming fomites. If a person then touches the object, for example a door handle, they can then transfer the virus to their mouth, eyes or nose leading to infection caused by fomite transmission.

Occasionally, zoonotic coronavirus can spill over into humans when people come into contact with either an infected or reservoir animal. These infections typically lead to a more destructive disease. Previous examples of spill over events include the 2002/2003 severe acute respiratory syndrome (SARS) CoV pandemic. The infection, transmitted the same way as human CoV, led to 8,000 infections with an overall mortality rate of approximately 10%. SARS CoV fatality rate increases with age. Less than 1% of 24 year olds and under died from the infection whereas 50% of over 65 year olds infected died. No new cases have been reported since 2004. Middle East respiratory syndrome (MERS) was first described in 2012 and since then 27 different countries have reported cases of MERS CoV. MERS CoV has more destructive pathology in comparison to SARS CoV and has the highest mortality rate of 35%.

Recently, a novel coronavirus (Wuhan pneumonia) has spilled over in Wuhan, China. The source of the infection is currently unknown. However, there are 314 cases confirmed globally with 51 cases defined as severely ill and several deaths have occurred (WHO situation report 22nd January). The majority of information on this novel coronavirus is currently unknown. However, transmission is believed to follow a similar path to other coronaviruses where droplet or close contact transmission can occur. The number of cases and deaths are expected to rise over time.

Clinical Features

Common human CoV have an incubation period of 1-3 days which is followed by rhinorrea, sore throat, fever, cough, malaise and headache. Occasionally, in at risk populations, the virus can cause lower respiratory tract infections such as bronchitis or pneumonia. These infections are often self-limiting and patients make a full recovery without seeking medical attention. 

CoV infections that spill over from animal populations seem to result in higher morbidity and mortality. SARS follows a similar clinical syndrome to human CoV but causes shortness of breath and usually progresses to pneumonia. MERS mirrors SARS except it often progresses to a pneumonia which is fatal in 4 out of every 10 patients diagnosed with the infection. Currently there is limited evidence on the clinical syndrome relating to novel CoV. However, as it is a respiratory syndrome, it is believed to follow similar pathologies and routes of transmission to SARS CoV and MERS CoV. It is suggested that 20% of patients with laboratory-confirmed infections are critically or severely ill.

Treatment and Prevention

There are currently no licensed antiviral agents or vaccines developed for use in coronavirus infections. Therefore, treatment is usually supportive care followed by infection control to prevent the spread of the virus. Infection control measures include personal protective equipment and quarantine of infected individuals. The best form of treatment is prevention typically in the form of a vaccine. However, as there are no options available, disinfection and sanitisation play a fundamental role in the containment of the spread of CoV. Due to the risk of transmission from contaminated surfaces and objects, persons should wash or disinfect their hands frequently. The risk of transmission is highest when entering an area with a high volume of people such as public transport, schools, offices, hospitals, and other public places. 

Disinfection and sanitation of areas where coronavirus transmission has occurred or is likely to occur is essential in containing an outbreak. These practices interrupt the chain of transmission. Byotrol has developed a highly effective antimicrobial disinfectant, Byotrol24, with proven residual self-sanitizing action for 24 hours, and efficacy against coronavirus as well as other enveloped viruses in just 1 minute. Frequent surface decontamination through cleaning and disinfection is a critical component of infection control. Using biocides such as Byotrol24 which have known virucidal efficacy against these viruses could aid to mitigate their transmission leading to lower infection rates, both within community and healthcare settings.