This document discusses incubation periods of diseases. It defines incubation period, latent period, and infectious period. It notes that incubation period is the time between transmission of an agent and first symptoms. Latent period is time between transmission and infectiousness, while infectious period is when an infected host can transmit. It lists factors that influence incubation periods like pathogen generation time and infective dose. It categorizes incubation periods as short (2-3 days for food poisoning and influenza), medium (10-21 days for measles and mumps), and long (weeks to years for hepatitis B and rabies). Finally, it discusses the importance of knowing incubation periods for tracing infections, determining quarantine periods, and prognosis.

1. Duhok polytechnic university
Shekhan technical college of health
Public health department
2nd stage
INCUBATION PERIOD
Prepared by :
Rathwan misle
Saher aswad
Zedo saido
Academic year: (2022-2023) Date:25/10/2022
Supervised by :
Dr. Alaa N. Sarkees
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2. Contents
 Terms of disease transmission
 Factors influencing incubation period
 Types of Incubation Period
 Importance of IP
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3. Terms of disease transmission:
Incubation period :
Time between transmission
of the agent and the first
symptoms of the disease.
Latent period : Time
between transmission of the
agent and the start of
infectiousness.
Infectious period :
period when an infected
host can transmit the agent
to another host.
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4. • If the latent period is longer than the incubation period,
individuals are contagious only after the onset of
symptoms
• If the latent period is shorter than the incubation period,
people are contagious before presenting symptoms
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5. Factors influencing incubation period:
• Generation time of pathogen
• Infective dose
• Portal of entry
• Individual susceptibility
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6. Types of Incubation Period
Short IP (2-3 days)
Food poisoning
Cholera
Dysentery
Influenza
Medium IP (10-21 days)
 Typhoid Fever
 Chickenpox
 Measles
 Mumps
Long IP (weeks-months-years)
Hepatitis B
Rabies
Leprosy
 AIDS 6

7. Importance of IP:
1) Tracing source of infection and
contacts:
This is use in diseases with shorter IP,
Food poisoning, dysentery, typhoid fever
Not particularly useful in diseases with
Longer IPs
2) Period of surveillance:
Helps in determining quarantine period
which is equal to maximum IP
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8. Importance of IP:
3) Identifying point source or propagated
epidemic:
In point source epidemic all cases fall
within the same incubation period
In propagated epidemics cases fall longer
than IP
4)Prognosis:
Shorter the IP, worse the prognosis
(tetanus, rabies)
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9. References
 Chan, Miranda; Johansson, Michael A. (Nov 30, 2018). "The
Incubation Periods of Dengue Viruses". PLOS ONE. 7 (11):
e50972. Bibcode:2012PLoSO...750972C.
doi:10.1371/journal.pone.0050972. PMC 3511440. PMID
23226436.
 Food poisoning symptoms & treatments - Illnesses &
conditions | NHS inform". Nhsinform.scot. 2020-02-26.
Retrieved 2020-05-07.
 World Health Organization (WHO), Severe acute respiratory
syndrome, www.who.int. Accessed 2012-05-28.
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10. THANK
YOU
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