Avian Influenza - a global threat

Abstract

Influenca ptica, popularno nazivana i ptičja gripa, uzrokuje velike štete u peradarstvu na Dalekom Istoku, ali i zabrinutost globalnih razmjera zbog širenja ovog virusa divljim pticama. Osim Dalekog Istoka, influenca ptica u protekle je dvije godine ćinila značajne probleme i u peradarstvu SAD-a, Kanade i Južnoafričke Republike. Do unatrag 10-ak godina nije bilo dokaza da virusi ptičje influnce mogu izravno zaraziti čovjeka i obratno. Izravni prijenos virusa influence s ptica na čovjeka prvi put je zapažen tijekom pojave visokopatogene influence u Hong Kongu 1997. uzrokovane podtipom virusa H5N1 kada je zaraženo 18, a umrlo 6 ljudi. Krajem 2003. na Dalekom Istoku ponovno izbija visokopatogena influenca te je po treći put od 1997. u ovoj regiji prouzročena podtipom H5N1. Zadnja od ove tri epizootije je započela u Južnoj Koreji i ubrzo se proširila u većini zemalja Dalekog Istoka. Za razliku od predhodnih pojava visokopatogene influence ptica, ovaj put virus prenose i divlje ptice te je zaraza do sada prenešena u većinu azijskih i europskih zemalja te u Afriku. Za očekivati je da će se bolest pojaviti i na drugim kontinentima. Najveću zabrinutost ipak je izazivalo zaražavanje ljudi sa smrtnošću od preko 50 %, kao i mogućnost da virus mutacijom stekne svojstvo interhumanog prijenosa što bi za posljedicu imalo novu pandemiju gripe.Avian influenza, also known as bird flu, causes enormous economic losses in poultry industry in the Far East, but also a global concern because of the spread of the virus by feral birds. Beside the Far East, avian influenza recently caused significant problems in poultry industry in the United States, Canada and South Africa. Until a decade ago, there was no evidence of spreading of the virus from birds to humans and vice versa. First direct transmission from birds to humans was reported in 1997 during an outbreak of highly pathogenic avian influenza in Hong Kong caused by H5N1 virus when 18 people became infected and six died. By the end of 2003 there was another outbreak of highly pathogenic avian influenza in the Far East and this was the third time in the region that it was caused by H5N1 subtype. The last H5N1 epidemic started in South Korea and soon spread to most Far East countries. In contrast to previous highly pathogenic avian influenza outbreaks, this time the virus was spread by feral birds and the infection was introduced in most of the Asian and European countries as well as in Africa. Nevertheless, the main concern is human infection with mortality above 50 % and possibility of the virus to mutate in a form capable for inter human transmission, which will result in new human influenza pandemic