Nosilci

Nosilci is a term used in biology and medicine to describe an individual or organism that harbors a pathogen and can transmit it to others, sometimes without showing symptoms. In public health, the concept helps explain how diseases spread and why outbreaks can persist even when many cases are detected.

There are several types of nosilci in the context of infectious diseases. Asymptomatic carriers harbor the pathogen but do not develop noticeable illness, yet they can shed and spread the pathogen. Incubating carriers are infected but not yet symptomatic, capable of transmitting the disease in the incubation period. Convalescent carriers continue to shed the pathogen after symptoms have subsided. Chronic carriers harbor the pathogen for extended periods, sometimes for life, and may intermittently release infectious particles. Nosilci can be humans, animals, or even insects that serve as reservoirs or intermediate hosts for a pathogen. Environmental nosilci—such as contaminated water or soil—can also play a role in transmission.

In genetics, the term is also used for individuals who carry a recessive allele without expressing the associated trait. For example, a person may be a carrier of a recessive genetic mutation (such as that for cystic fibrosis) without having the disease, but they can pass the allele to offspring.

Detection and management of nosilci involve screening, testing, and contact tracing to prevent transmission. Public health measures may include isolation or treatment of carriers, vaccination, hygiene improvements, and surveillance. Ethical considerations focus on privacy, stigma, and the rights of individuals who are identified as carriers.

Historical examples include chronic carriers of Salmonella typhi, famously referred to in relation to the case commonly known as “Typhoid Mary,” illustrating how a carrier state can sustain transmission even without apparent illness.