EMERGING AND RE-EMERGING INFECTIOUS DISEASES

Emerging infectious diseases are diseases of infectious origin whose incidence in humans have increased within the past decades or threatens to increase in the near future. The reappearance of a previously known infection after a period of disappearance or decline in incidence is known as re-emergence. Factors such as environmental degradation, rapid population growth, poverty, increased international travel, microbial adaptation of antibiotics, and development of insecticidal resistance and the collapse of public health systems may contribute to the emergence or re-emergence of a disease. Despite the discovery of antibiotics and vaccines, the world continues to be vulnerable to new, emerging, and re-emerging microbial diseases. New diseases in India include HIV/AIDS and a new strain of cholera (V. cholerae 0139) that emerged in 1992. Tuberculosis, malaria, dengue hemorrhagic fever and dengue shock syndrome, Japanese encephalitis, meningococcal meningitis, and hepatitis B .The outbreak of a plague epidemic in India in 1994 and the resurgence of Kala-Azar and epidemics of Leptospirosis are examples of the re-emergence of once-controlled infectious diseases. Preventive efforts and policies to ensure adequate supplies of appropriate medicines, and establishment of national and regional surveillance and diagnostic facilities for combating infectious disease threats should be established.