Virology - Study of viruses

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Natural Reservoir ---> Disease Reservoir

Introduction:

A natural reservoir or nidus (the latter from the Latin word for "nest") is the long-term host of a pathogen of an infectious disease.[1] Hosts often do not get the disease carried by the pathogen, or it is carried as a subclinical infection and so is asymptomatic and non-lethal. Once discovered, natural reservoirs elucidate the complete life cycle of infectious diseases, providing effective prevention and control.

A disease reservoir is the habitat (animate or inanimate) where an infectious agent is naturally found, where it grows, and multiplies.[2][3] It is where an organism lives when it is not causing illness or disease.[3] What further defines a reservoir (for a specific pathogenic organism) is the inability of the organism to thrive upon its removal from the habitat.[2] There are three main types of reservoirs: human, non-human animals, and environmental.[3] A "multi-host" organism is capable of having more than one natural reservoir.

https://www.cdc.gov/ophss/csels/dsepd/ss1978/lesson1/section10.html

10.3201/eid0812.010317

Janeway CA Jr, Travers P, Walport M, et al. Immunobiology: The Immune System in Health and Disease. 5th edition. New York: Garland Science; 2001. Infectious agents and how they cause disease. Available from: https://www.ncbi.nlm.nih.gov/books/NBK27114/

Human Reservoirs holds potential pathogens that exists on or inside the human species.[3]

Non-Human Reservoirs consist of domesticated and wild animals.[3][2]

Environmental Reservoirs hold infectious agents that such as plants, soil, and water. The bacteria Legionella pneumonphila (causes Legionnaires' disease) and Vibrio cholerae (causes Cholera) are both naturally found in water sources.[3][4]

Disease Transmission

A disease reservoir acts as a transmission point between a pathogen and susceptible host.[3] Transmission can occur directly or indirectly.[5][3]

Direct transmission can occur from direct contact or direct droplet spread.[5] Direct contact transmission between two people can happen through the touching of skin, through kissing, and sexual contact.[5][3] Humans as disease reservoirs can be symptomatic (showing illness) or asymptomatic (not showing illness), act as disease carriers, and often spread illness unknowingly.[3] Direct droplet spread is do to solid particles or liquid droplet suspended in air for some time.[5] Droplet spread is considered the transmission of the pathogen to susceptible host within a meter of distance, they can spread from coughing, sneezing, and talking.[5][3]

Indirect transmission can occur from air particles, vehicles (including fomites), and vectors.[3] Airborne transmission is different from direct droplet spread as it is defined as disease transmission that takes place over a distance larger than a meter.[5] Pathogens that can be transmitted trough airborne sources are carried by particles such as dust or dried residue (referred to as droplet nuclei).[5][3] Vehicles act as a passive transmission point between pathogen and susceptible host.[5] Food, water, blood, and fomites are examples of vehicles.[3] Fomites are inanimate objects (doorknobs, medical equipment, etc.) that become contaminated by a reservoir source or someone/something that is a carrier.[5] A vehicle - like a reservoir - may also be a favorable environment for the growth of an infectious agent, coming into contact with a vehicle leads to its transmission. Vector transmission occurs most often from insect bites from mosquitos, flies, fleas, and ticks.There are two sub categories of vectors: mechanical (an insect transmits pathogen to host without it affecting the insect itself) and biological (reproduction of the pathogen occurs within the vector and is transmitted to a host).

Reservoir Identification and Disease Control and Eradication

  1. ^ Aguirre, A. Alonso; Ostfeld, Richard; Daszak, Peter. New Directions in Conservation Medicine: Applied Cases of Ecological Health. Oxford University Press; 28 June 2012. ISBN 9780199731473. p. 196.
  2. ^ a b c "Identifying Reservoirs of Infection: A Conceptual and Practical Challenge". Emerging Infectious Diseases. 8 (12): 1468–1473. doi:10.3201/eid0812.010317.
  3. ^ a b c d e f g h i j k l m n "Principles of Epidemiology | Lesson 1 - Section 10". www.cdc.gov. Retrieved 2017-11-10.
  4. ^ Nelson, Eric J.; Harris, Jason B.; Morris, J. Glenn; Calderwood, Stephen B.; Camilli, Andrew (2009/10). "Cholera transmission: the host, pathogen and bacteriophage dynamic". Nature Reviews Microbiology. 7 (10): 693–702. doi:10.1038/nrmicro2204. ISSN 1740-1534. {{cite journal}}: Check date values in: |date= (help)
  5. ^ a b c d e f g h i "Modes of Disease Transmission | Microbiology". courses.lumenlearning.com. Retrieved 2017-12-05.