Coronaviruses are a large family of RNA viruses that infect humans as well as some animal species. In humans, coronaviruses can cause a variety of symptoms, ranging from a simple cold to severe acute respiratory syndrome type 2 (SARS).
SARS-CoV-2 is a new strain of the virus, which was not previously detected in humans, and initially appeared in the Chinese city of Wuhan in November 2019. The virus rapidly spread worldwide, resulting in the declaration of a pandemic by the World Health Organisation (WHO), in March 2020.
According to scientists, this is a newly discovered coronavirus which results in multisystem disease, that does not only include serious respiratory illness but also other extrapulmonary manifestations such as complications in the kidneys, liver, thrombotic, cardiovascular, endocrinological, gastrointestinal, gastrointestinal, neurological. This is mainly due to the fact that the virus receptor enters the cells and is expressed in many extrapulmonary tissues, thus contributing to their immediate damage but also to the deregulation of the body’s immune responses.
The virus is human-to-human transmissible, most likely through droplets of saliva and mucus during coughing, sneezing and other human contact like handshaking and sharing food or drink. In most cases, symptoms are noticeable within the first 5 days of infection, however the incubation period varies from 1 to 14 days. Even asymptomatic carriers can transmit the virus. A key prevention tactic to stop coronavirus transmission is to detect cases in isolation and isolate them as well as their close contacts.
Diagnosis is carried out through Real-Time Polymerase Chain Reaction (PCR) technique which is performed in the molecular department of our laboratory. Sample collection is done by trained nurses in a specially designed space, on the ground floor of our premises, collecting a nasal and pharyngeal smear, then the sample is stored in a special transport medium and transferred to the molecular department, while following all the related rules of biosafety. The procedure starts with the extraction of nucleic acids from the sample, which is carried out automatically by four state-of-the-art extractors available in our laboratory, minimising the factor human error while maximising the sensitivity of the method. Subsequently, polymerase chain reaction takes place by highly trained molecular biologists of our laboratory, using multipliers manufactured by leading companies in molecular applications, such as QIAGEN and DNA technology.
Specific primers for the conserved areas of the viral genome and double-labelled probes are utilized to amplify and detect SARS-CoV-2 RNA extracted from biological samples. The method uses Taqmanprobes to detect E (Envelope) and N (Nucleocapsid) genes of SARS-CoV-2, as well as the E-gene region common to all SARS-like coronaviruses (SARS-CoV, SARS-CoV- 2). The detection of two different genes of SARS-CoV-2 enables the detection of viral RNA in the sample, even in the case of the presence mutation in one of the two viral genes detected, maximizing, in this way, the method sensitivity even if the viral load in the possible case is minimal. Internal Process Control (IPC), which is added during RNA extraction, is detected in the same reaction as a labelled probe and allows the detection of RT-PCR inhibition by various agents. It also acts as a control by ensuring that viral RNA is isolated from the biological sample, thus preventing false negative results due to insufficient amount of genetic material or improper sample transfer. Results analysis is done by the specialized and experienced staff, thus increasing the reliability of the results given to the candidates to be examined and help in protecting the population from possible cases with low viral load, that may be undetectable by alternative, less reliable methods, therefore, minimising the spread of the virus in the community.
The ethos, professionalism and advanced technology of the molecular department, make us at the forefront of the effort to stop the pandemic on our island.