Listed below is a selection of viruses that are of relevance to the indoor environment. They can contaminate the air and/or surfaces indoors and have the potential to cause serious illness. This is not an exhaustive list. If you wish to test your product against a particular virus, please contact us to discuss feasibility. Surrogate viruses are used in place of viruses which cause severe infections such as SARS and MERS as detailed below.
Influenza A (H1N1), part of the Orthomyxoviridae family, is a single-stranded RNA enveloped virus ranging from 80-120 nm in diameter. Influenza A virus is responsible for many epidemics of respiratory illness, including the swine-flu epidemic of 2009. Associated with increased rates of hospitalisation and death in susceptible individuals, influenza viruses are spread from person-to-person via large virus-containing droplets and aerosols that are produced by coughing, sneezing or talking. Influenza viruses may also be spread via contaminated fomites or by direct contact. At airmid healthgroup, Influenza A (H1N1) virus has been validated for use in virus removal and inactivation studies based in the environmental test chamber or test duct and laboratory, depending on our clients' requirements.
Rhinovirus, part of the Picornoviridae family, is a small single-stranded RNA non-enveloped virus around 27 nm in diameter. Rhinovirus is among the most common viral infective agents in humans and accounts for more than 80% of common colds. The main route of transmission of Rhinovirus is via aerosols, droplets and by direct contact with infected individuals or via indirect contact from contaminated surfaces or fomites. At airmid healthgroup, Rhinovirus has been validated for use in virus removal studies based in the environmental test chamber or test duct and laboratory, depending on our clients' testing requirements.
Norovirus (formerly Norwalk agent), a single-stranded RNA non-enveloped virus 38-40 nm in diameter, is part of the Caliciviridae family. Norovirus is recognized as the cause of 90% of epidemic non-bacterial outbreaks of gastroenteritis around the world. Norovirus is highly contagious with multiple modes of transmission including via faecal-contaminated food or water, person-to-person contact, aerosol droplets or fomites. It is relatively stable in the environment and is resistant to disinfectants. As Norovirus adapts well to cell culture, and owing to its contagious nature, surrogates of the virus are commonly used instead, such as Feline Calicivirus (FCV), also part of the Caliciviriadae family. At airmid healthgeroup, FCV has been validated as a Norovirus surrogate for use in virus removal studies based in the environmental test chamber or test duct and laboratory, depending on our clients, testing requirements.
Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV), part of the Coronaviridae family, is a single-stranded RNA enveloped virus 100-140 nm in diameter. SARS-CoV is associated with severe pneumonia, acute respiratory distress and has a high risk of a fatal outcome (10% morality rate). SARS-CoV was first identified in 2003 when an epidemic commenced in China, where it was thought to be spread from small mammals (most likely bats) to humans. SARS can be spread by inhaling small droplets of nasal secretions, via direct contact with an infected person or via fomites. Murine Hepatitis Virus or Bovine Coronavirus belong to the same genus (Betacoronaviruses) as SARS-CoV, which implies that both viruses have a close phylogenetic relationship with SARS-CoV. Both of these viruses have been used as surrogates for SARS-CoV in the literature and can be used for product testing at airmid healthgroup.
Middle East Respiratory Syndrome Coronavirus (MERS-CoV): Like SARS-CoV, MERS-CoV is part of the Coronaviridae family, but seems to have originated in Saudi Arabia in 2012. It is believed to have originated in bats, with camels suggested as a possible intermediate host. MERS-CoV causes similar symptoms to SARS-CoV including acute respiratory distress, but has a higher mortality rate (around 30%). The route of transmission is thought to be similar to SARS-CoV, primarily via respiratory droplets, but transmission via the oral route or via urine cannot yet be excluded. Murine Hepatitis Virus or Bovine Coronavirus belong to the same family as MERS-CoV and could potentially be used as surrogates for MERS-CoV. Transmissible Gastroenteritis Virus (TGEV), a severe acute respiratory syndrome coronavirus, is also a SARS-CoV surrogate in the literature, and could be used as a surrogate for MERS-CoV.
MS2 Coliphage: MS2 Coliphage has been used as a surrogate virus in numerous studies relating to virus contamination of air, water and food as it mimics the behaviour of pathogenic viruses, while being harmless to humans and animals. The MS2 coliphage (Leviviridae family) is a bacteriophage that specifically infects Escherichia coli (Migula 1895) and is a non-enveloped ssRNA icosahedral virus with a diameter of 25-27nm. MS2 coliphage is similar in morphology to Picornoviruses and can persist as an infectious virus in the environment comparable with the most resistant human pathogens in the Picornoviridae family e.g. poliovirus, rhinovirus and enterovirus. Based on these characteristics it is an ideal surrogate for small enteric viruses and has been validated for use at airmid healthgroup.
Other viruses of interest:
Adenovirus is part of the Adenoviridae family and is a non-enveloped double-stranded DNA virus of 75nm diameter. Adenovirus infections play a major role in most major respiratory disease syndromes in children under 6, causing laryngitis, croup, bronchitis, bronchiolitis, pertussis-like syndromes and pneumonia (also conjunctivitis and diarrhoea). Adenovirus can be spread from an infected person to others via direct contact, from their coughing or sneezing or via touching contaminated surfaces. The virus can be shed by infected individuals in the faeces for months after recovery.
Respiratory Syncytial Virus of the Paramyxoviridae family, is a single-stranded RNA enveloped virus 80-350nm in diameter. RSV causes mild cold-like symptoms in adults but can cause airway infections (e.g. bronchiolitis and pneumonia) in infants and young children. The virus is spread via tiny droplets in the air after an infected person coughs or sneezes. It can also be transmitted by direct contact with an infected person or via contaminated surfaces such as door knobs or toys.
Human Parainfluenza Virus (HPIV) is part of the Paramyxoviridae family and is a single-stranded RNA enveloped virus approximately 200nm in diameter. HPIV causes upper or lower respiratory tract infections, usually with mild symptoms. However HPIV can cause more severe lower respiratory illness such as croup or pneumonia in young children and older adults. Similar to Rhinoviruses, HPIV is transmitted via aerosols, direct contact with infected individuals or via indirect contact from contaminated surfaces or fomites.