Source of infections

The object in which the etiological agent (EA) survives and reproduces is its source.

It can be: (note: in the absolutist concept it is always only a man or an animal).
 * man',
 * animal,
 * under certain circumstances also the external environment' where it can reside saprophytically (Legionella, mycoses)

One can exclude EA':
 * already during the incubation period (HAV, HBV) (dangerous due to ignorance of own infectivity);
 * further in case of own disease' - patient sick with a clinical form, abortive, atypical or inapparent'';
 * convalescent can also still rule out EA (pertussis);
 * A special type of source is bacillus carrier - short-term (salmonella), long-term/lifelong (typhoid), intermittent ' (at certain periods).

We call diseases transmitted from animals zoonoses (tularemia, anthrax, brucellosis, salmonellosis, Q fever). The most common zoonosis in the Czech Republic is campylobacteriosis, the second most common is salmonellosis. From domestic animals, the main sources are cattle, sheep, goats, ducks, chickens, pigeons, dogs and cats, and from wild animals, deer, roe deer and small rodents.

The reservoir of infection is the environment (living and non-living) in which the EA survives or proliferates. It can also be an intermediate host (snail/plh - schistosomiasis).

If we want to end the cycle of contagion at the source, we can make it his
 * insulation',
 * treatment or
 * killing. The third option concerns animals, e.g. in case of rabies. With certain reservations, this also includes the culling of cow herds during the BSE, foot-and-mouth disease epidemic, or the killing of birds during avian flu.

Related Articles

 * Bloodborne Diseases