Does COVID-1 9 pose a threat for humans? [Polish]

SARS-CoV-2, the causative agent of COVlD-19 is a zoonotic pathogen. Natural infections with this virus occur in non-human primates, canids, feiids, minks and apparently many other species, including wildlife and laboratory animals are susceptible. It has been also proved that pets, mostly dogs and cats, that were in close contact with their owners suffering from COViD-19 have also become infected. These animals have angiotensin-converting enzyme 2 receptor (ACE2) with high affinity for SARS-COV-2, so are permissive to infection, they also exhibit sustained viral shedding and can transmit the virus to conspecifics. None of herbivorous species as cattle, sheep, goat, alpaca and also rabbit shed infectious virus via nasal, oral or fecal routes, although viral RNA was detected in several animals. Neutralizing antibody are either absent or of low titers one month after infection. The domestic livestock contribute to SARS-CoV-2 epidemiology. COVlD-19 cases due to the contact with mink could suggest that animal to human viral transmission is possible. The white-tailed deer in the populations have been exposed to SARS-CoV-2 and it can infect multiple domestic and wild animal species. Though the SARS-CoV-2 causes few or no clinical symptoms in most animal species, some scientists fear that wildlife might become a reservoir of infection, thus possibly viral mutations. In this review, current information about SARS-CoV-2 infection in animals and the potential spread of the virus to humans through contact with dogs, cats, ferrets, hamsters, farmed minks, cattle, pigs, laboratory animals, white-tailed deer, and 200 animals was presented and discussed.

Epidemics and pandemics of infectious disease

Throughout the course of civilization, epidemics and pandemics have ravaged humanity, destroyed animal breeding and horticulture, and has also changed the course of history. It has been estimated that Justinian plague has affected half of the population of Europe and killed in three pandemics 50 million people, the avian-borne flu (Spanish flu), resulted in 50 million deaths worldwide in the years 1918-1919, and recently the COVID-19 is officially a pandemic, after barreling through 114 countries in just three months. In the past, rinderpest has hit Europe with three long panzootics, African swine fever (ASF), is still a threat to both the swine production industry and the health of wild boar populations. Several molecular changes occur in the pathogen that may trigger an epidemic or even pandemic. These include increase of virulence, introduction into a novel host, and changes in host susceptibility to the pathogen. Once the infectious disease threat reaches an epidemic or pandemic level, the goal of the response is to mitigate its impact and reduce its incidence, morbidity and mortality as well as disruptions to economic, political, and social systems. An epidemic curve shows progression of illnesses in an outbreak over time and the SIR, SI, SIRD and SEIR represent the simplest compartmental models that enable simplify the mathematical modelling of epidemics. This article throws a light on changing ideas in epidemiology of infectious diseases.