Ellen W. Collisson, M.S., Ph.D., Professor, Western University of Health Sciences, Pomona, CA, Professor Emerita, Texas A&M University, College Station, TX
Sažetak
Od novog tisućljeća, dvije emergentne virusne bolesti imale su velik utjecaj na međunarodnu javnost. Virusi ptičje gripe su zajednički patogeni ptica i šire se svijetom putem njihovih migrirajućih domaćina predstavljajući potencijalnu prijetnju kao emergentne bolesti za ljude, posebice kroz infekcije farmskih životinja. Koronavirus teškog akutnog respiratornog sindroma (SARSCoV) proizišao iz skupine prethodno nepoznatih virusa koji inficiraju šišmiše, ali s potencijalom da inficiraju ostale sisavce, uzrokuje tešku bolest u ljudi. Iako postoje mnoge sličnosti između ova dva vrlo kontagiozna tipa virusa, postoje također i jasne razlike. Dok smo se sa SARSCoV epidemijama u ljudi uspjeli nositi, ako ne i eliminirati, virusi ptičje gripe i dalje ostaju prijetnja i razlog za međunarodnu zabrinutost. Oba su respiratorni virusi, ali SARSCoV ima tendenciju pokazivanja kliničkih znakova bolesti ubrzo nakon infekcije dok infekcija virusima ptičje gripe može biti inaparentna. Oba su sposobna za brzi razvoj, kroz mutacije koje jačaju odnosno podižu njihovu patogenost i sklonost domaćinu. Genetske promjene koronavirusa mogu se dogoditi rekombinacijama, a u slučaju virusa ptičje gripe miješanjem genoma. Genetske izmjene u oba virusa mogu se dogoditi mutacijama. Promjena (prijelaz) tih virusa se, barem dijelom, čini zbog mutacija koje utječu na bjelančevine koje su inicijalno u infekciji odgovorne za prihvaćanje virusa na stanice. Dokumentirana pojava ovih virusa u ljudi nudi mogućnost razumijevanja prijenosa ovakvih bolesti životinja na ljude.
Abstract
Since the new millennium, two emerging viral diseases have made quite an impact internationally. Avian influenza viruses are common pathogens of birds and spread worldwide by their migratory hosts presenting a potential threat as an emerging disease to humans, especially through infection of agricultural animals. The severe acute respiratory syndrome coronavirus (SARSCoV) emerged from a group of previously unknown viruses commonly infecting bats, but with the potential to transmit to other mammals, causing severe illness in humans. Although there are many similarities between these two highly contagious types of viruses, there are also distinct differences. Whereas the SARSCoV outbreaks in humans have been managed, if not eliminated, avian influenza viruses continue to be a threat of international concern. Both are respiratory viruses but SARSCoV tends to display clinical illness soon after infection whereas infection may be unapparent with AIV.
Both are capable of readily evolving, through mutations that alter their pathogenesis and host preference. Genetic shifts may occur in coronaviruses by recombination and in influenza viruses by reassortment of genomes. Genetic drift in both viruses may occur through point mutations. The transition of these viruses at least in part appears to be due to mutations affecting the proteins that initially in infection are responsible for attachment of the viruses to the cell. The documented emergence of these viruses to humans offers a window of understanding of the transmission of non-human animal disease to humans.