Recent developments in the epidemiology of virus diseases and BSE.

The article discusses the continuous evolution of viral epidemics, focusing on the impact of genetic mutations and host resistance in the emergence of new diseases like AIDS, hemorrhagic fevers and bovine spongiform encephalopathy (BSE) in both humans and animals.

Continuous Evolution of Viral Diseases

• The research talks about constant changes taking place in the sphere of viral epidemics, affecting both humans and animals. These changes include variation in clinical symptoms of diseases, their time span or even complete disappearance, and emergence of new diseases.
• Three primary factors are attributed to this continuous evolution: the etiological agent (the cause or manner of causation of diseases), the host in which the virus propagates, and the environmental conditions.

Role of Genetic Alterations

• Two major mechanisms through which genetic alterations of the virus contribute to disease evolution are discussed: recombination and reassortment mutations.
• Recombination is the process where genetic material from two parent molecules is brought together within one molecule. On the other hand, reassortment is the mixing of the genetic material of a species into new combinations in different individuals.
• These genetic alterations can cause the emergence of new disease strains or influence the progression of existing diseases.

Selection for Resistance or Susceptibility

• The research acknowledges the role of selection for resistance or susceptibility in affecting disease the course and outcome of disease developments.
• Resistance refers to the ability of an organism to defend against a disease agent, whereas susceptibility implies the opposite – the lack of resistance to a disease.
• This interplay between resistance and susceptibility can influence the prevalence and severity of a disease in a particular population.

Newly Emerged Diseases: AIDS, Hemorrhagic Fevers, and BSE

• The article then discusses the epidemiology – the study of disease occurrence and its control in a population – of newly emerged diseases in detail, presenting examples of both human and animal diseases. These examples include Acquired Immunodeficiency Syndrome (AIDS), hemorrhagic fevers, and bovine spongiform encephalopathy (BSE), also known as mad cow disease.
• Other disease examples provided are canine hemorrhagic gastroenteritis (a severe illness in dogs causing vomiting and bloody diarrhea) and respiratory syndrome in horses.