Viral Zoonoses – A Threat under Control?

Abstract

Despite intensive research and considerable effort to eradicate infectious diseases, modern medicine has failed to control many infectious diseases which have been thought to be easy to overcome with advances in medical science and technology. In fact, infectious diseases remain a dominant feature in public health considerations for the 21st century. Some infectious agents already known to be pathogenic have gained increasing importance in recent decades due to changes in disease patterns. Furthermore, many new, previously unknown infectious agents with a high pathogenic potential have been identified. Nearly all of these emergent disease episodes have involved zoonotic or species-jumping infectious agents. The complex interaction of factors like environmental and ecological changes, social factors, decline of health care, human demographics and behaviour influences the emergence of re-emergence of such diseases. Viruses, especially RNA viruses with their ability to adapt quickly to changing environmental conditions, are among the most prominent examples of emerging pathogens. In this review, we present the important examples of zoonotic viruses and discuss the factors playing a key role in the emergence and resurgence of these diseases.

Global Host Immune Response: Pathogenesis and Transcriptional Profiling of Type A Influenza Viruses Expressing the Hemagglutinin and Neuraminidase Genes from the 1918 Pandemic Virus

“…The causes of the high lethality and profound lung pathology that were consequences of 1918 influenza cases remain largely unknown. The emergence of novel influenza viruses and associated epidemics in human populations is thought to occur largely from zoonotic transfer from animal strains (4,43,46,63,(74)(75)(76), and additional influenza pandemics have occurred in 1957 with the "Asian" influenza virus (H2N2) and in 1968 with the "Hong Kong" influenza virus (H3N2), which were estimated to be responsible for approximately 70,000 and 34,000 additional influenza-related deaths, respectively, in the United States (49,56,60,62,78). This is further evidenced by the recent emergence of highly pathogenic avian H5N1 influenza viruses in Hong Kong in 1997, which showed unusually high lethality in humans.…”

Wie gefährlich ist die Vogelgrippe für den Menschen?

“…Die WHO warnt davor, dass die Infektion jederzeit wieder aufflackern kann, weil die Erreger als sog. "re-emerging viruses" [18] in der natürlichen Umgebung weiterhin vorkommen. Sorge bereitet Experten die Mög-lichkeit eines genetischen "reassortment" durch eine gleichzeitige Doppelinfektion eines Wirts (Mensch, Schwein) von humanen und aviären Influenza-A-Viren.…”

Emerging viral threats in Gabon: health capacities and response to the risk of emerging zoonotic diseases in Central Africa

“…Furthermore, some well known pathogens have been expanding their territories, causing increasing concerns in the recent decades due to changing epidemiological patterns. 2 Most of these EID events have involved zoonotic infectious agents: more than 60% of EID affecting humans have a zoonotic origin 3,4 and B75% of the diseases that have emerged over the past two decades have wildlife sources. 5 Therefore, zoonotic EID represent a major and increasing threat to global health.…”

“…For instance, territories (that is: city, district) with an inefficient disease detection system or a failure to control vectors and other carriers of diseases as well as man-made environmental changes (breakdown of the water system, deforestationy) will force an increase in contact between the human population and wildlife. 2,8 Tropical forests form the ecosystem harboring the highest species richness of all terrestrial ecosystems and shelter almost 50% of the total global biodiversity. 9,10 This includes wildlife, flora, multi-cellular organisms as well as an immense diversity of pathogens including bacteria, parasites and viruses.…”