Communicable diseases

Improved living standards, sanitation, food control, vaccines, and antibiotics have reduced the toll of communicable diseases, saving millions of lives. Smallpox was eradicated in 1977, and poliomyelitis eradication is near. Measles has been reduced drastically, yet outbreaks occur where immunization lags. HIV/AIDS emerged in the 1980s and quickly became a global pandemic costing millions of lives. Despite progress, it remains a major global health issue. Progress has been made in malaria and tuberculosis control, yet they still cause millions of deaths. Influenza pandemics with new, deadly versions continue to appear. Neglected tropical diseases are responding to global efforts. Emerging diseases in the 21st century have led to pandemics, especially COVID-19, the most serious global pandemic since the 1918 H1N1 flu pandemic. Other viral diseases have emerged, moved to new regions, become endemic, such as West Nile fever and Zika virus disease, and spread geographically. Rapid urbanization, changing ecology, and mass travel allow infectious diseases transmitted from animals to humans in isolated villages or Chinese “wet markets” to quickly become global coronavirus pandemics. New viruses or bacteria, antibiotic resistance, and microorganisms such as hepatitis C and Helicobacter pylori that cause noncommunicable diseases—e.g., liver and stomach cancer—pose new challenges for infectious disease control. Public health and clinical care require increasing political, financial, and scientific support and great tenacity to develop treatments, vaccines, and delivery systems to meet 21st-century challenges, such as coronaviruses, other emerging diseases, and pandemic prevention and mitigation. Public health must be prioritized to continue the progress in controlling, eliminating, and eradicating poliomyelitis, measles, and neglected tropical diseases. Scientific advances in microbiology and genetics will advance to new successes in vaccinology and therapeutics to meet old and new communicable disease challenges, including diseases of poverty in countries at all developmental and income levels.