![]() ![]() The SARS epidemic in 2003 reported 8098 cases with 774 deaths, and was eventually brought under control by July 2003, in a matter of 8 months. COVID-19 spread is facilitated by population densities, urbanization, mass gatherings and superspreading events. The higher asymptomatic rate, further compounded by pre-symptomatic transmission has made containment much harder for COVID-19 than for SARS. Risk factors for severe disease outcomes include older age and co-morbidities. R0 above 1 will lead to propagation and further growth of the outbreak. The basic reproductive number R0 is 2–3, indicating that every case leads to 2–3 secondary cases), is similar or somewhat higher to that of SARS. The main transmission route is via respiratory droplets, and the angiotensin converting enzyme 2 (ACE2), found in the lower respiratory tract of humans, has been identified as the receptor used for cell entry for both SARS and SARS-CoV-2. Live animal markets selling multiple species of wild and domestic animals in proximity to large populations of densely housed humans are thought to be the source of both outbreaks. SARS-CoV-2 is most likely of bat origin, similar to its predecessor SARS virus that caused the SARS outbreak in 2003. The current pandemic is caused by a coronavirus of zoonotic origin -SARS-CoV-2-, that emerged in Wuhan, China, by the end of 2019, and was rapidly declared a public health emergency of international concern (PHEIC). This review examines emerging or re-emerging viral infections of the past two decades, their characteristics and the risk of geographic spread via air travel. For diseases with high potential of geographic spread associated with high case fatalities, rigorous mobility and travel restrictions are being deployed. Despite these differences, policy responses used to tackle viral epidemics have tended to be similar across time and countries – social distancing, quarantines, school closures, and information campaigns are the policy instruments normally available, in addition to vector control campaigns for vector-borne viral diseases, personal protection, and most importantly, vaccines. pregnant women for Zika and the elderly for COVID-19, their vectors of transmission, their fatality rate, and their transmissibility often measured as basic reproduction number. Viral outbreaks differ in many ways, such as the individuals most at risk e.g. SummaryĬOVID-19 is not associated with the highest case fatality rate compared with other emerging viral diseases such as SARS and Ebola, but the combination of a high reproduction number, superspreading events and a globally immunologically naïve population has led to the highest global number of deaths in the past 20 decade compared to any other pandemic.Įmerging infectious disease outbreaks are most likely to originate in wildlife, and are increasing significantly over time correlated with socio-economic, environmental, ecological factors combined with increasing mobility and globalization including climate change. The risk of geographic spread via air travel differs significantly between emerging infectious diseases. ![]() How does COVID-19 compare with other emerging viral diseases of the past two decades? Recent findings The rapid spread was facilitated by air travel although rigorous travel bans and lockdowns were able to slow down the spread. The COVID-19 pandemic poses a major global health threat. ![]()
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