Incubation period

Last updated
In some diseases, as depicted in this diagram, the latency period is shorter than the incubation period. After the latency period (but before clinical infection) the infected person can transmit the disease without signs of any symptoms. Such infection is called subclinical infection. Concept of incubation period.svg
In some diseases, as depicted in this diagram, the latency period is shorter than the incubation period. After the latency period (but before clinical infection) the infected person can transmit the disease without signs of any symptoms. Such infection is called subclinical infection.

Incubation period (also known as the latent period or latency period) is the time elapsed between exposure to a pathogenic organism, a chemical, or radiation, and when symptoms and signs are first apparent. [1] In a typical infectious disease, the incubation period signifies the period taken by the multiplying organism to reach a threshold necessary to produce symptoms in the host.

Contents

While latent or latency period may be synonymous, a distinction is sometimes made whereby the latent period is defined as the time from infection to infectiousness. Which period is shorter depends on the disease. A person may carry a disease, such as Streptococcus in the throat, without exhibiting any symptoms. Depending on the disease, the person may or may not be contagious during the incubation period.

During latency, an infection is subclinical. With respect to viral infections, in incubation the virus is replicating. [2] This is in contrast to viral latency, a form of dormancy in which the virus does not replicate. An example of latency is HIV infection. HIV may at first have no symptoms and show no signs of AIDS, despite HIV replicating in the lymphatic system and rapidly accumulating a large viral load. People with HIV in this stage may be infectious.

Intrinsic and extrinsic incubation period

The terms "intrinsic incubation period" and "extrinsic incubation period" are used in vector-borne diseases. The intrinsic incubation period is the time taken by an organism to complete its development in the definitive host. The extrinsic incubation period is the time taken by an organism to develop in the intermediate host.[ citation needed ]

For example, once ingested by a mosquito, malaria parasites must undergo development within the mosquito before they are infectious to humans. The time required for development in the mosquito ranges from 10 to 28 days, depending on the parasite species and the temperature. This is the extrinsic incubation period of that parasite. If a female mosquito does not survive longer than the extrinsic incubation period, then she will not be able to transmit any malaria parasites.[ citation needed ]

But if a mosquito successfully transfers the parasite to a human body via a bite, the parasite starts developing. The time between the injection of the parasite into the human and the development of the first symptoms of malaria is its intrinsic incubation period. [3]

Determining factors

The specific incubation period for a disease process is the result of multiple factors, including:[ citation needed ]

Examples for diseases in humans

Due to inter-individual variation, the incubation period is always expressed as a range. When possible, it is best to express the mean and the 10th and 90th percentiles, though this information is not always available.

For many conditions, incubation periods are longer in adults than they are in children or infants.

Diseasebetweenand
Cellulitis caused by Pasteurella multocida 0 days [4] 1 day
Chicken pox 9 days [5] 21 days
Cholera 0.5 days [6] 4.5 days
Common cold 1 day [7] [8] 3 days
COVID-19 2 days [9] 11.5 [10] /12.5 [11] /14 days
Dengue fever 3 days [12] 14 days
Ebola 1 day [13] 21 (95%), 42 (98%) days
Erythema infectiosum (Fifth disease)13 days [14] 18 days
Giardia 3 days21 days
HIV 2 weeks to months, or longer [15] 3 weeks to months, or longer
Infectious mononucleosis (glandular fever)28 days [16] 42 days
Influenza 1 day [17] 3 days
Kuru disease 10.3 years (mean) [18] 13.2 years
Leprosy 1 year [19] 20 or more years
Marburg 5 days [20] 10 days
Measles 9 days [21] 12 days
MERS 2 days [22] 14 days
Mumps 14 days [23] 18 days
Norovirus 1 day [24] 2 days
Pertussis (whooping cough)7 days [25] 14 days
Polio 7 days [26] 14 days
Rabies 1 months, but may vary from <1 week to rarely >1 year. [27] [28] 3 months
Rocky Mountain spotted fever 2 days [29] 14 days
Roseola 5 days [30] 15 days
Rubella (German measles)14 days [31] 21 days
Salmonella 12 days [31] 24 days
Scarlet fever 1 day [32] 4 days
SARS 1 day [33] 10 days
Smallpox 7 days [34] 17 days
Tetanus 7 days [35] 21 days
Tuberculosis 2 weeks [36] 12 weeks
Typhoid 7 days21 days

See also

Related Research Articles

<span class="mw-page-title-main">Malaria</span> Mosquito-borne infectious disease

Malaria is a mosquito-borne infectious disease that affects vertebrates. Human malaria causes symptoms that typically include fever, fatigue, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. Symptoms usually begin 10 to 15 days after being bitten by an infected Anopheles mosquito. If not properly treated, people may have recurrences of the disease months later. In those who have recently survived an infection, reinfection usually causes milder symptoms. This partial resistance disappears over months to years if the person has no continuing exposure to malaria.

<span class="mw-page-title-main">West Nile fever</span> Human disease caused by West Nile virus infection

West Nile fever is an infection by the West Nile virus, which is typically spread by mosquitoes. In about 80% of infections people have few or no symptoms. About 20% of people develop a fever, headache, vomiting, or a rash. In less than 1% of people, encephalitis or meningitis occurs, with associated neck stiffness, confusion, or seizures. Recovery may take weeks to months. The risk of death among those in whom the nervous system is affected is about 10 percent.

<span class="mw-page-title-main">Dengue fever</span> Mosquito-borne disease

Dengue fever is a mosquito-borne disease caused by dengue virus, prevalent in tropical and subtropical areas. It is frequently asymptomatic; if symptoms appear they typically begin 3 to 14 days after infection. These may include a high fever, headache, vomiting, muscle and joint pains, and a characteristic skin itching and skin rash. Recovery generally takes two to seven days. In a small proportion of cases, the disease develops into severe dengue with bleeding, low levels of blood platelets, blood plasma leakage, and dangerously low blood pressure.

<span class="mw-page-title-main">Q fever</span> Coxiella burnetii infection

Q fever or query fever is a disease caused by infection with Coxiella burnetii, a bacterium that affects humans and other animals. This organism is uncommon, but may be found in cattle, sheep, goats, and other domestic mammals, including cats and dogs. The infection results from inhalation of a spore-like small-cell variant, and from contact with the milk, urine, feces, vaginal mucus, or semen of infected animals. Rarely, the disease is tick-borne. The incubation period can range from 9 to 40 days. Humans are vulnerable to Q fever, and infection can result from even a few organisms. The bacterium is an obligate intracellular pathogenic parasite.

<span class="mw-page-title-main">Chikungunya</span> Infection caused by the Chikungunya virus

Chikungunya is an infection caused by the Chikungunya virus (CHIKV). The disease was first identified in 1952 in Tanzania and named based on the Kimakonde words for "to become contorted".

<span class="mw-page-title-main">Giardiasis</span> Parasitic disease that results in diarrhea

Giardiasis is a parasitic disease caused by Giardia duodenalis. Infected individuals who experience symptoms may have diarrhoea, abdominal pain, and weight loss. Less common symptoms include vomiting and blood in the stool. Symptoms usually begin one to three weeks after exposure and, without treatment, may last two to six weeks or longer.

<span class="mw-page-title-main">Ascariasis</span> Disease caused by the parasitic roundworm Ascaris lumbricoides

Ascariasis is a disease caused by the parasitic roundworm Ascaris lumbricoides. Infections have no symptoms in more than 85% of cases, especially if the number of worms is small. Symptoms increase with the number of worms present and may include shortness of breath and fever in the beginning of the disease. These may be followed by symptoms of abdominal swelling, abdominal pain, and diarrhea. Children are most commonly affected, and in this age group the infection may also cause poor weight gain, malnutrition, and learning problems.

<span class="mw-page-title-main">Arbovirus</span> Class of viruses which are transmitted by arthropods

Arbovirus is an informal name for any virus that is transmitted by arthropod vectors. The term arbovirus is a portmanteau word. Tibovirus is sometimes used to more specifically describe viruses transmitted by ticks, a superorder within the arthropods. Arboviruses can affect both animals and plants. In humans, symptoms of arbovirus infection generally occur 3–15 days after exposure to the virus and last three or four days. The most common clinical features of infection are fever, headache, and malaise, but encephalitis and viral hemorrhagic fever may also occur.

<span class="mw-page-title-main">Asymptomatic carrier</span> Organism which has become infected with a pathogen but displays no symptoms

An asymptomatic carrier is a person or other organism that has become infected with a pathogen, but shows no signs or symptoms.

Tick-borne diseases, which afflict humans and other animals, are caused by infectious agents transmitted by tick bites. They are caused by infection with a variety of pathogens, including rickettsia and other types of bacteria, viruses, and protozoa. The economic impact of tick-borne diseases is considered to be substantial in humans, and tick-borne diseases are estimated to affect ~80 % of cattle worldwide. Most of these pathogens require passage through vertebrate hosts as part of their life cycle. Tick-borne infections in humans, farm animals, and companion animals are primarily associated with wildlife animal reservoirs. Many tick-borne infections in humans involve a complex cycle between wildlife animal reservoirs and tick vectors. The survival and transmission of these tick-borne viruses are closely linked to their interactions with tick vectors and host cells. These viruses are classified into different families, including Asfarviridae, Reoviridae, Rhabdoviridae, Orthomyxoviridae, Bunyaviridae, and Flaviviridae.

<span class="mw-page-title-main">Oropouche fever</span> Medical condition

Oropouche fever is a tropical viral infection which can infect humans. It is transmitted by biting midges and mosquitoes, from a natural reservoir which includes sloths, non-human primates, and birds. The disease is named after the region where it was first discovered and isolated in 1955, by the Oropouche River in Trinidad and Tobago. Oropouche fever is caused by the Oropouche virus (OROV), of the Bunyaviridae order of viruses.

<span class="mw-page-title-main">Waterborne disease</span> Diseases caused by pathogenic microorganisms transmitted by waters

Waterborne diseases are conditions caused by pathogenic micro-organisms that are transmitted by water. These diseases can be spread while bathing, washing, drinking water, or by eating food exposed to contaminated water. They are a pressing issue in rural areas amongst developing countries all over the world. While diarrhea and vomiting are the most commonly reported symptoms of waterborne illness, other symptoms can include skin, ear, respiratory, or eye problems. Lack of clean water supply, sanitation and hygiene (WASH) are major causes for the spread of waterborne diseases in a community. Therefore, reliable access to clean drinking water and sanitation is the main method to prevent waterborne diseases.

<span class="mw-page-title-main">Lymphatic filariasis</span> Medical condition

Lymphatic filariasis is a human disease caused by parasitic worms known as filarial worms. Usually acquired in childhood, it is a leading cause of permanent disability worldwide, impacting over a hundred million people and manifesting itself in a variety of severe clinical pathologies While most cases have no symptoms, some people develop a syndrome called elephantiasis, which is marked by severe swelling in the arms, legs, breasts, or genitals. The skin may become thicker as well, and the condition may become painful. Affected people are often unable to work and are often shunned or rejected by others because of their disfigurement and disability.

<span class="mw-page-title-main">Subclinical infection</span> Nearly or completely asymptomatic infection

A subclinical infection—sometimes called a preinfection or inapparent infection—is an infection by a pathogen that causes few or no signs or symptoms of infection in the host. Subclinical infections can occur in both humans and animals. Depending on the pathogen, which can be a virus or intestinal parasite, the host may be infectious and able to transmit the pathogen without ever developing symptoms; such a host is called an asymptomatic carrier. Many pathogens, including HIV, typhoid fever, and coronaviruses such as COVID-19 spread in their host populations through subclinical infection.

<span class="mw-page-title-main">Mosquito-borne disease</span> Diseases caused by bacteria, viruses or parasites transmitted by mosquitoes

Mosquito-borne diseases or mosquito-borne illnesses are diseases caused by bacteria, viruses or parasites transmitted by mosquitoes. Nearly 700 million people contract mosquito-borne illnesses each year, resulting in more than a million deaths.

Queensland tick typhus is a zoonotic disease caused by the bacterium Rickettsia australis. It is transmitted by the ticks Ixodes holocyclus and Ixodes tasmani.

<i>Zika virus</i> Species of flavivirus

Zika virus is a member of the virus family Flaviviridae. It is spread by daytime-active Aedes mosquitoes, such as A. aegypti and A. albopictus. Its name comes from the Ziika Forest of Uganda, where the virus was first isolated in 1947. Zika virus shares a genus with the dengue, yellow fever, Japanese encephalitis, and West Nile viruses. Since the 1950s, it has been known to occur within a narrow equatorial belt from Africa to Asia. From 2007 to 2016, the virus spread eastward, across the Pacific Ocean to the Americas, leading to the 2015–2016 Zika virus epidemic.

<span class="mw-page-title-main">Latent period (epidemiology)</span> Time interval between infection by a pathogen and the individual becoming infectious

In epidemiology, particularly in the discussion of infectious disease dynamics (modeling), the latent period is the time interval between when an individual or host is infected by a pathogen and when that individual becomes infectious, i.e. capable of transmitting pathogens to other susceptible individuals.

<span class="mw-page-title-main">Symptoms of COVID-19</span>

The symptoms of COVID-19 are variable depending on the type of variant contracted, ranging from mild symptoms to a potentially fatal illness. Common symptoms include coughing, fever, loss of smell (anosmia) and taste (ageusia), with less common ones including headaches, nasal congestion and runny nose, muscle pain, sore throat, diarrhea, eye irritation, and toes swelling or turning purple, and in moderate to severe cases, breathing difficulties. People with the COVID-19 infection may have different symptoms, and their symptoms may change over time. Three common clusters of symptoms have been identified: one respiratory symptom cluster with cough, sputum, shortness of breath, and fever; a musculoskeletal symptom cluster with muscle and joint pain, headache, and fatigue; and a cluster of digestive symptoms with abdominal pain, vomiting, and diarrhea. In people without prior ear, nose, or throat disorders, loss of taste combined with loss of smell is associated with COVID-19 and is reported in as many as 88% of symptomatic cases.

<span class="mw-page-title-main">Henry Rose Carter</span> American epidemiologist (1852–1925)

Henry Rose Carter was an American physician, epidemiologist, and public health official who served as assistant surgeon general of the Public Health Service Commissioned Corps. His research and protocols were critical in understanding and preventing the transmission of both malaria and yellow fever.

References

  1. Lesson 1, Section 9: Natural History and Spectrum of Disease, Principles of Epidemiology in Public Health Practice, Third Edition, An Introduction to Applied Epidemiology and Biostatistics, Centers for Disease Control and Prevention, May 18, 2012
  2. Sharara, A. I. (1997). "Chronic hepatitis C". Southern Medical Journal. 90 (9): 872–7. doi:10.1097/00007611-199709000-00002. PMID   9305294. S2CID   9838013.
  3. Chan, Miranda; Johansson, Michael A. (Nov 30, 2012). "The Incubation Periods of Dengue Viruses". PLOS ONE. 7 (11): e50972. Bibcode:2012PLoSO...750972C. doi: 10.1371/journal.pone.0050972 . PMC   3511440 . PMID   23226436.
  4. Cellulitis, kidshealth.org. Accessed 2012-05-28.
  5. "Chickenpox: Practice Essentials, Background, Pathophysiology". March 22, 2020 via eMedicine.{{cite journal}}: Cite journal requires |journal= (help)
  6. Azman, Andrew S.; Rudolph, Kara E.; Cummings, Derek A.T.; Lessler, Justin (2013). "The incubation period of cholera: A systematic review". Journal of Infection. 66 (5): 432–8. doi:10.1016/j.jinf.2012.11.013. PMC   3677557 . PMID   23201968.
  7. Lessler, Justin; Reich, Nicholas G; Brookmeyer, Ron; Perl, Trish M; Nelson, Kenrad E; Cummings, Derek AT (2009). "Incubation periods of acute respiratory viral infections: A systematic review". The Lancet Infectious Diseases. 9 (5): 291–300. doi:10.1016/S1473-3099(09)70069-6. PMC   4327893 . PMID   19393959.
  8. Common cold, The Mayo Clinic, mayoclinic.com. Accessed 2012-05-28.
  9. Linton, Natalie M.; Kobayashi, Tetsuro G; Yang, Yichi; Hayashi, Katsuma M; Akhmetzhanov, Andrei R. E; Jung, Sung-mok; Yuan, Baoyin; Kinoshita, Ryo; Nishiura1, Hiroshi (2020). "Incubation Period and Other Epidemiological Characteristics of 2019 Novel Coronavirus Infections with Right Truncation: A Statistical Analysis of Publicly Available Case Data". J Clin Med. 9 (2): 538. doi: 10.3390/jcm9020538 . PMC   7074197 . PMID   32079150.{{cite journal}}: CS1 maint: numeric names: authors list (link)
  10. Lauer, Stephen A.; Grantz, Kyra H.; Bi, Qifang; Jones, Forrest K.; Zheng, Qulu; Meredith, Hannah R.; Azman, Andrew S.; Reich, Nicholas G.; Lessler, Justin (March 10, 2020). "The Incubation Period of Coronavirus Disease 2019 (COVID-19) From Publicly Reported Confirmed Cases: Estimation and Application". Annals of Internal Medicine. 172 (9): 577–582. doi:10.7326/M20-0504. PMC   7081172 . PMID   32150748.
  11. Li, Qun; Guan, Xuhua; Wu, Peng; Wang, Xiaoye; Zhou, Lei; Tong, Yeqing; Ren, Ruiqi; Leung, Kathy S.M.; Lau, Eric H.Y.; Wong, Jessica Y.; Xing, Xuesen; Xiang, Nijuan; Wu, Yang; Li, Chao; Chen, Qi; Li, Dan; Liu, Tian; Zhao, Jing; Liu, Man; Tu, Wenxiao; Chen, Chuding; Jin, Lianmei; Yang, Rui; Wang, Qi; Zhou, Suhua; Wang, Rui; Liu, Hui; Luo, Yinbo; Liu, Yuan; Shao, Ge; Li, Huan; Tao, Zhongfa; Yang, Yang; Deng, Zhiqiang; Liu, Boxi; Ma, Zhitao; Zhang, Yanping; Shi, Guoqing; Lam, Tommy T.Y.; Wu, Joseph T.; Gao, George F.; Cowling, Benjamin J.; Yang, Bo; Leung, Gabriel M.; Feng, Zijian (March 26, 2020). "Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus–Infected Pneumonia". New England Journal of Medicine. 382 (13): 1199–1207. doi:10.1056/NEJMoa2001316. PMC   7121484 . PMID   31995857.
  12. Gubler, D. J. (1998). "Dengue and dengue hemorrhagic fever". Clinical Microbiology Reviews. 11 (3): 480–96. doi:10.1128/CMR.11.3.480. PMC   88892 . PMID   9665979.
  13. Are the Ebola outbreaks in Nigeria and Senegal over?, World Health Organization, who.int. Accessed 2014-10-21.
  14. Erythema Infectiosum at eMedicine
  15. Kahn, James O.; Walker, Bruce D. (1998). "Acute Human Immunodeficiency Virus Type 1 Infection". New England Journal of Medicine. 339 (1): 33–9. doi:10.1056/NEJM199807023390107. PMID   9647878.
  16. Macnair, Trisha, Glandular fever, BBC, bbc.co.uk. Accessed 2012-05-28.
  17. Seasonal Influenza (Flu), Centers for Disease Control and Prevention, cdc.gov. Accessed 2012-05-28.
  18. Huillard d'Aignaux, J. N.; Cousens, S. N.; MacCario, J; Costagliola, D; Alpers, M. P.; Smith, P. G.; Alpérovitch, A (2002). "The incubation period of kuru". Epidemiology. 13 (4): 402–8. doi: 10.1097/00001648-200207000-00007 . PMID   12094094. S2CID   22810508.
  19. "Leprosy Fact sheet N°101". World Health Organization. January 2014. Archived from the original on 2013-12-12.
  20. Questions and Answers About Marburg Hemorrhagic Fever Archived 2016-03-03 at the Wayback Machine , Centers for Disease Control and Prevention, cdc.gov. Accessed 2012-05-28.
  21. Measles, American Osteopathic College of Dermatology, aocd.org. Accessed 2012-05-28.
  22. "MERS Clinical Features". CDC.gov. CDC. 2 August 2019. Retrieved 22 March 2020.
  23. Mumps Disease, Questions & Answers Archived 2007-11-20 at the Wayback Machine , vaccineinformation.org. Accessed 2012-05-28.
  24. Norovirus, Centers for Disease Control and Prevention, cdc.gov. Accessed 2012-05-28.
  25. Pertussis, GPnotebook, gpnotebook.co.uk. Accessed 2012-05-28.
  26. Polio, GPnotebook, gpnotebook.co.uk. Accessed 2012-05-28.
  27. "WHO - Rabies". who.int.
  28. "Rabies vaccines: WHO position paper – April 2018" (PDF). WHO . April 2018 via apps.who.int.
  29. Rocky Mountain Spotted Fever Archived 2016-03-04 at the Wayback Machine , About.com. Accessed 2012-05-28.
  30. Roseola Infantum at eMedicine
  31. 1 2 Dermatologic Manifestations of Rubella at eMedicine
  32. Scarlet Fever at eMedicine
  33. World Health Organization (WHO), Severe acute respiratory syndrome, www.who.int. Accessed 2012-05-28.
  34. Smallpox Disease Overview Archived 2013-04-02 at the Wayback Machine , Centers for Disease Control and Prevention, cdc.gov. Accessed 2012-05-28.
  35. Tetanus at eMedicine
  36. "Tuberculosis (TB)". MedicineNet. Retrieved 22 March 2020.