BY KURNIAWATI KAMARUDIN

KUALA LUMPUR: In any outbreak of a viral infection, it is important to identify the exposure route or pathway of the virus to humans.

In the case of Covid-19 – which has claimed the lives of thousands of people worldwide – the coronavirus that causes the disease is known to be transmitted to humans through inhalation and absorption. It can be transmitted from human to human within a range of 1.8 metres through body fluids, namely droplets generated by coughing and sneezing.

Universiti Kebangsaan Malaysia (UKM) senior lecturer at the Department of Earth Sciences and Environment Dr Mohd Shahrul Mohd Nadzir, who is an air quality expert, said studies have shown that airborne transmission had played an important role in the epidemiology of two previous coronavirus outbreaks, namely Severe Acute Respiratory Syndrome (SARS) in 2003 in China and Middle East Respiratory Syndrome (MERS) in 2012 in the Arabian peninsula.

(Airborne transmission occurs when viruses are carried by small particles suspended in the air; it is different from transmission through droplets where people can get infected by coming into contact with droplets generated by coughing and sneezing.)

And, during the avian influenza outbreak in the US state of Iowa in 2014-2015 that was caused by the HPA1 H5 virus, particulate substances were found to have carried the virus, he said.   

Researchers, he added, found that particulates (solid and liquid particles suspended in the air) carrying the virus from chicken coops infected thousands of other chickens which badly impacted the state’s poultry industry.

Airborne transmission

Mohd Shahrul said studies by international scientists on whether particulate matter can carry the Covid-19 virus are still at the preliminary stage.

“It can be possible for the (Covid-19) virus to be transmitted through particulate matter in the air if it serves as a ‘host’.

“It’s important to carry out studies on the involvement of particulate matter because it is capable of carrying the virus more than two meters high in the air in enclosed spaces such as homes, hospitals and other buildings,” he told Bernama.

He also cited last month’s studies by scientists from the US-based National Institutes of Health’s National Institute of Allergy and Infectious Diseases who discovered that SARS-CoV-2 – the virus that causes Covid-19 – can remain active in aerosols (suspension of fine solid particles or liquid droplets in air or another gas) for up to three hours; four hours on copper surfaces; up to 24 hours on cardboard surfaces; and two to three days on plastic and stainless steel surfaces.

“This means the Covid-19 virus can be ‘transferred’ from any surface to another host,” he pointed out.

Local research efforts

Meanwhile, a team of researchers from UKM has embarked on a preliminary study to evaluate the transmission risk of the Covid-19 virus through particulate matter inside buildings.

The team, headed by Mohd Shahrul, comprises experts in the fields of air quality, virology and medicine. The team is collaborating with Hospital Cancelor Tuanku Muhriz (HCTM), Malaysia Genome Institute and Universiti Malaya in their study.

According to Mohd Shahrul, his team spent seven days collecting air samples from the Covid-19 operations centre at UKM’s HCTM in Cheras.

He said his team would be able to derive data and early findings from their study by the middle of this month.

He said preliminary findings from their study would help to determine if particulates of less than 2.5 micrometres in diameter can carry the Covid-19 virus.

“It’s important to know this because only small particulates can enter the respiratory tract and into the lungs,” he said, adding that he hoped their study would help hospitals to take proactive steps to curb the transmission of the virus.

Good ventilation

Mohd Shahrul said if it is proven that particulate matter is capable of carrying the Covid-19 virus, immediate steps must be taken to optimise filtration technologies or the use of humidifiers in enclosed spaces.

“When an infected patient is inside a building, the dust from his footsteps and movements will float in the air as particulate matter which will circulate the room and move to other parts of the building.

“This is the reason why good ventilation is important for buildings so that the air (inside the building) does not become an agent for virus carriers,” he added. – Bernama