The World Health Organization (WHO) is a specialized agency of the United Nations based in Geneva. The WHO has many initiatives that center around health. Primarily, they lead global efforts to expand universal health coverage using science-based policies and programs. They are also responsible for shaping health research agendas and developing norms and standards.
The WHO provides expert team support, including funding, vaccines, testing, and treatment tools at the country level to fight...

Infectious diseases appear in populations through various transmission patterns, influenced by pathogen characteristics, population immunity, environmental conditions, and social behavior. Understanding these patterns is essential for effective public health surveillance and intervention. These categories—sporadic, outbreak, epidemic, pandemic, and endemic—help frame the nature and scope of disease events.Sporadic diseases occur irregularly and infrequently, without a predictable temporal or...

Cells are sometimes infected by more than one virus at once. When two viruses disassemble to expose their genomes for replication in the same cell, similar regions of their genomes can pair together and exchange sequences in a process called recombination. Alternatively, viruses with segmented genomes can swap segments in a process called reassortment.

Influenza is an acute, highly communicable viral disease that affects the respiratory tract and is responsible for seasonal epidemics worldwide. Influenza A is the most prevalent type associated with widespread outbreaks and is subtyped based on two surface glycoproteins: hemagglutinin (H) and neuraminidase (N), as in H1N1. These glycoproteins are essential for viral infectivity, transmission, and immune recognition. Transmission occurs primarily through respiratory droplets and contaminated...

When a person's physical, emotional, intellectual, social development or spiritual functioning is compromised, this deviation from a healthy normal state is called illness. Illness creates stress that in turn harms individuals. Irritation, anger, denial, hopelessness, and fear are behavioral and emotional changes an individual experiences in the phases of illness. A variety of factors influence a person's health and well-being.
For instance, risk factors are connected to illness, disability,...

Plague is a highly virulent zoonotic disease caused by Yersinia pestis, a Gram-negative, facultatively anaerobic coccobacillus. This pathogen primarily circulates among rodent populations and is transmitted to humans through the bite of infected fleas. Additional transmission routes include direct contact with infected animal tissue or inhalation of respiratory droplets from individuals with pneumonic plague. These multiple transmission pathways highlight the bacterium’s potential for rapid...