diseases, with the theoretical potential to become pandemics. Their ability to spread efficiently enough to cause a pandemic is limited, however, as transmission of these viruses requires close contact with the infected vector, and the vector has only a short time before death or serious illness. Furthermore, the short time between a vector becoming infectious and the onset of symptoms allows medical professionals to quickly quarantine vectors and prevent them from carrying the pathogen elsewhere. Genetic mutations could occur, which could elevate their potential for causing widespread harm; thus, close observation by contagious disease specialists is merited. Coronaviruses Coronaviruses (CoV) are a large family of viruses that cause illness ranging from the common cold to more severe diseases such as Middle East respiratory syndrome (MERS-CoV) and severe acute respiratory syndrome (SARS-CoV-1). A new strain of coronavirus (SARS-CoV-2) causes Coronavirus disease 2019, or COVID-19, which was declared as a pandemic by the WHO on 11 March 2020. Some coronaviruses are zoonotic, meaning they are transmitted between animals and people. Detailed investigations found that SARS-CoV-1 was transmitted from civet cats to humans and MERS-CoV from dromedary camels to humans. Several known coronaviruses are circulating in animals that have not yet infected humans. Common signs of infection include respiratory symptoms, fever, cough, shortness of breath, and breathing difficulties. In more severe cases, an infection can cause pneumonia, acute respiratory distress syndrome, kidney failure, and even death. Standard recommendations to prevent the spread of infection include regular hand washing, wearing a face mask, going outdoors when meeting people, and avoiding close contact with people who have tested positive regardless of whether they have symptoms or not. It is recommended that people stay two meters or six feet away from others, commonly called social distancing. Severe acute respiratory syndrome After the SARS outbreak, in 2003 the Italian physician Carlo Urbani (1956–2003) was the first to identify severe acute respiratory syndrome (SARS) as a new and dangerously contagious disease, although he became infected and died. It is caused by a coronavirus dubbed SARS-CoV-1. Rapid action by national and international health authorities such as the World Health Organization helped to slow transmission and eventually broke the chain of transmission, which ended the localized epidemics before they could become a pandemic. However, the disease has not been eradicated and could re-emerge. This warrants monitoring and reporting of suspicious cases of atypical pneumonia. Influenza Wild aquatic birds are the