Vector (biology)

In biology and medicine, a vector (from the Latin vector 'traveler', 'carrier') or disease carrier is a very general carrier of pathogens that cause infectious diseases . The vector transports a pathogen from the host to another organism without becoming ill itself. This also applies to humans and animals with infections that are contagious during the incubation period . This corresponds to an indirect route of infection . There are two types of transmission.

Biological transmission

In biological transmission, also known as active transmission , a type of pathogen is ingested by a special vector - for example a blood-sucking insect  - while eating from an infected main host . The pathogen survives in the vector organism, it can possibly also multiply and / or change there. The next time the vector is fed to a living being that has not yet been infected, this new victim is infected. The vector acts here as an intermediate host . In the case of biological transmission, the basic principle is that each vector can only transmit the pathogen that is specific to it.
Examples are the yellow fever mosquito as the carrier of yellow fever and the Zika virus and the ticks as the carrier of TBE and Lyme borreliosis .

Transition from MERS-CoV and SARS-CoV-1 to humans

The transition from MERS-CoV to humans probably comes from bats and dromedaries as carriers, SARS-CoV-1 from horseshoe bats and via the raccoon dog to humans. In the case of SARS-CoV-2 , various animal species are discussed as transmitters to humans, especially the horseshoe bats and also the raccoon dog ( sea fox fur) bred in China for fur production . Symptom-free or still symptom-free people infected with SARS-CoV-2 play a role as potential vectors from person to person.

Mechanical transmission

In mechanical transmission, also known as passive transmission , the vector is only externally contaminated with one or more pathogens and transfers these to another organism via contact infection ( smear infection ). Examples are the housefly , the blowfly and the cockroach . The vector acts here as a transport host. In mechanical transmission, a vector can transmit all kinds of pathogens. Transport over a longer period of time is only possible if the pathogen is insensitive to air.

Web links

Commons : Vectors  - collection of images, videos, and audio files

• Spread and transmission of infectious diseases
• Anthropophilic blood-sucking arthropods in Germany with their most important potential vector properties
• Information on disease carriers relevant in Europe from the European Center for Disease Prevention and Control (ECDC)
• Vector-borne diseases at the WHO

See also

Vector (genetic engineering)

Zoonosis

Individual evidence

1. ↑ vector. In: WordNet Search 3.1. Retrieved May 5, 2020 . 
2. ^ C. Frank, M. Faber et al .: Important vector-borne infectious diseases in humans in Germany - Epidemiological aspects . In: Federal Health Gazette. 2014, doi: 10.1007 / s00103-013-1925-9 .
3. ↑ M. Coleman, Matthew B. Frieman: Coronaviruses: Important Emerging Human Pathogens . In: Journal of Virology. May 2014, Volume 88, No. 10, pp. 5209-5212, doi: 10.1128 / JVI.03488-13 .
4. ↑ Fabian Schmidt: The raccoon dog as a coronavirus sling? On: dw.com on April 29, 2020.
5. ↑ James D. Cherry, Paul Krogstad: SARS: The First Pandemic of the 21st Century . In: Pediatric Research. Volume 56, 2004, pp. 1-5, doi: 10.1203 / 01.PDR.0000129184.87042.FC .
6. ↑ Wycliffe E. Wei, Zongbin Li et al .: presymptomatic transmission of SARS-CoV 2 In: CDC: Morbidity and Mortality Weekly Report. (MMWR) April 10, 2020, Volume 69, No. 14, pp. 411-415.