What environmental economic political changes in the past 50

What environmental, economic, political changes in the past 50 years have contributed to the emergence of microbial epidemics due to HIV, West Nile Virus, Ebola, and re-emergence of epidemics due to Mycobacterium tuberculosis?

Solution

The emergence and pandemic spread of the acquired immunodeficiency syndrome has posted the greatest challenge to public health in modern times.full consequence of this may not be evident for several years because of the silent spread and slow evolution of this infection.In 1985 ELISA test become available for detection of anti HIV antibodys, till then the infection detected only when patient developed clinical features such as apportunistic infections and malignancys. West nail virus isolated in 1937 from west Nile povinance of Uganda.this virus is maintained in nature by wild birds by culex mosquitos.in 1999 , west nail fever unexpectedly appeared in New York and since then virus spread over much of the USA and becoming major health problem. The reservoir of Ebola virus and its natural history still remain unclear, dispite frequent outbreaks with high fatality.it is first seen in 1976 , similar to heamarrhagic fever with high fatality.spread by person to person. Mycobacterium tuberculosis, the mode of infection is by direct inhalation of bacilli by coughing, sneezing and speaking.the number, virulence factors, host factors, age, immunity, stress and nutrition influence the outcome of infection.about two million people are infected with tuberculosis.poverty and tuberculosis seen in poor countries. A close relationship with HIV and tuberculosis emergence is seen. Primary infection mostly to childrens by detection of enlarged cervical lymph nodes.