A focus of infection is a place containing whatever epidemiological factors are needed for transmission of an infection. Any focus of infection will have a source of infection, and other common traits of such a place include a human community, a vector population, and environmental characteristics adequate for spreading infection.

Examples of focus of infection

Water pump in 1854 London

In 1854 London physician

John Snow John Snow (15 March 1813 – 16 June 1858) was an English physician and a leader in the development of anaesthesia and medical hygiene. He is considered one of the founders of modern epidemiology, in part because of his work in tracing the so ...

discovered that people who drank from a particular water pump contracted

cholera Cholera is an infection of the small intestine by some strains of the bacterium ''Vibrio cholerae''. Symptoms may range from none, to mild, to severe. The classic symptom is large amounts of watery diarrhea that lasts a few days. Vomiting and ...

, and proposed that drinking this water from this pump was the cause of the illness. At the time people did not readily believe germ theory of disease, instead favoring

miasma theory The miasma theory (also called the miasmatic theory) is an obsolete medical theory that held that diseases—such as cholera, chlamydia, or the Black Death—were caused by a ''miasma'' (, Ancient Greek for 'pollution'), a noxious form of "bad ...

. The discovery of the water pump as a source of infection set a precedent which helped establish epidemiology as a science.

Gay bathhouses, particularly in 1980s

A gay bathhouse is a place where men who have sex with men meet for sex. In the 1980s at the advent of HIV/AIDS many men who used bathhouses for sex developed AIDS as a consequence of their having sex without using

safe sex Safe sex is sexual activity using methods or contraceptive devices (such as condoms) to reduce the risk of transmitting or acquiring sexually transmitted infections (STIs), especially HIV. "Safe sex" is also sometimes referred to as safer se ...

practices for the

prevention of HIV/AIDS HIV prevention refers to practices that aim to prevent the spread of the human immunodeficiency virus (HIV). HIV prevention practices may be undertaken by individuals to protect their own health and the health of those in their community, or may ...

. Consequently, public health policies found bathhouses to be a place to target for public health intervention.

Child daycare

Childcare infection Infection in childcare is the spread of infection during childcare, typically because of contact among children in daycare or school. This happens when groups of children meet in a childcare environment, and there any individual with an infectious ...

is the spread of infection during childcare, typically because of contact among children in daycare or school. This happens when groups of children meet in a childcare environment, and there any individual with an infectious disease may spread it to the entire group. Commonly spread diseases include

influenza-like illness Influenza-like illness (ILI), also known as flu-like syndrome or flu-like symptoms, is a medical diagnosis of possible influenza or other illness causing a set of common symptoms. These include fever, shivering, chills, malaise, dry cough, lo ...

and enteric illnesses, such as diarrhea among babies using diapers. It is uncertain how these diseases spread, but hand washing reduces some risk of transmission and increasing hygiene in other ways also reduces risk of infection.

References

{{reflist Epidemiology Public health