An understanding of the mode of transmission of bacteria and other infectious agents is extremely important from a public health perspective, because interrupting the chain of transmission is an excellent way to prevent infectious diseases. The mode of transmission of many infectious diseases is "human-to-human" but infectious diseases are also transmitted from nonhuman sources such as soil, water, and animals. Fomites are inanimate objects, such as towels, that serve as a source of microorganisms that can cause infectious diseases.
Although some infections are caused by members of the normal flora, most are acquired by transmission from external sources. Pathogens exit the infected patient most frequently from the respiratory and gastrointestinal tracts; hence, transmission to the new host usually occurs via airborne respiratory droplets or fecal contamination of food and water. Organisms can also be transmitted by sexual contact, urine, skin contact, blood transfusion, contaminated needles, or biting insects. The transfer of blood, either by transfusion or by sharing needles during intravenous drug use, can transmit various bacterial and viral pathogens. The screening of donated blood for Treponema pallidum, HIV, human T-cell lymphotropic virus, hepatitis B virus, hepatitis C virus, and West Nile virus has greatly reduced the risk of infection by theses organisms.
Bacteria, viruses, and other microbes can also be transmitted from mother to offspring, a process called vertical transmission. Animals are also an important source of organisms that infect humans. The can be either the source or the mode of transmission of certain organisms. So we can greatly reduce the chances of infectious diseases by interrupting the chain of transmission.
Although some infections are caused by members of the normal flora, most are acquired by transmission from external sources. Pathogens exit the infected patient most frequently from the respiratory and gastrointestinal tracts; hence, transmission to the new host usually occurs via airborne respiratory droplets or fecal contamination of food and water. Organisms can also be transmitted by sexual contact, urine, skin contact, blood transfusion, contaminated needles, or biting insects. The transfer of blood, either by transfusion or by sharing needles during intravenous drug use, can transmit various bacterial and viral pathogens. The screening of donated blood for Treponema pallidum, HIV, human T-cell lymphotropic virus, hepatitis B virus, hepatitis C virus, and West Nile virus has greatly reduced the risk of infection by theses organisms.
Bacteria, viruses, and other microbes can also be transmitted from mother to offspring, a process called vertical transmission. Animals are also an important source of organisms that infect humans. The can be either the source or the mode of transmission of certain organisms. So we can greatly reduce the chances of infectious diseases by interrupting the chain of transmission.
