Glossary · Epidemiology
Incubation period
Interval between exposure to a pathogen and the onset of the first symptoms. For Andes virus: 7 to 42 days, on average 18 to 24 days.
The incubation period is the interval between exposure to a pathogen and the onset of the first symptoms in the infected person. For the Andes virus responsible for the MV Hondius event, it ranges from 7 to 42 days, with an average of 18 to 24 days. This is the longest range observed for a hantavirus, which shapes the entire surveillance arrangement for passengers and contacts.
Definition and mechanism #
Definition #
The incubation period corresponds to the interval between the penetration of the infectious agent into the organism and the moment it manifests clinically. It depends on several parameters: virulence and tropism of the agent, infectious dose received, route of entry, immune status and age of the person, genetic variability between strains.
Distinction from other durations #
Incubation is to be distinguished from the latent period (interval between infection and the start of contagiousness) and the infectious period (interval during which the person is contagious). For hantavirus diseases, contagiousness only begins with symptom onset — there is no documented transmission during the asymptomatic phase.
Incubation period of hantavirus diseases #
Andes virus #
Andes virus has the longest incubation period among known hantaviruses: 7 to 42 days, on average 18 to 24 days. This feature requires extended surveillance of exposed persons: 42 days after the last possible exposure.
Other strains #
Other hantaviruses show similar but variable durations:
- Sin Nombre virus (North America): 1 to 5 weeks, on average 2 to 3 weeks.
- Eurasian hantaviruses (Hantaan, Seoul, Puumala): 1 to 8 weeks for hemorrhagic fever with renal syndrome.
WHO uses an overall range of 1 to 8 weeks for human hantavirus diseases as a whole.
Consequences for surveillance #
Quarantine and follow-up duration #
The international rule is to follow contacts for the maximum known incubation duration of the disease. For Andes virus, this is 42 days. This duration is three times longer than that used for COVID-19 (14 days) or Ebola (21 days), mobilising health resources for nearly six weeks.
Application to MV Hondius #
For the 149 people disembarked in Tenerife (Granadilla de Abona) on 10 May 2026, the surveillance window ends at the end of June 2026. Throughout this period, the health authorities of the 10 countries concerned actively follow contacts: daily symptom surveillance, direct access to a referral physician, immediate isolation upon onset of any suggestive sign.
Why this duration is reassuring #
The longer the incubation period, the wider the window of opportunity to intercept a symptomatic case before it infects those around them. Combined with active surveillance and person-to-person transmission accounting for only 2 to 5% of cases, the WHO assessment of risk to the general population as "low" rests partly on the operational relevance of this prolonged surveillance.
Key figures
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7 to 42 days
Incubation period of Andes virus, the longest range observed for a hantavirus.
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18 to 24 days
Average incubation observed for Andes virus.
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1 to 8 weeks
Range observed for hantavirus diseases overall (all strains combined).
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42 days
Medical surveillance duration applied to MV Hondius passengers and contacts after their last exposure.
Standards & references
- WHO — Epidemiological definitions — WHO defines the incubation period as the interval between infection and the appearance of the first clinical signs.
Frequently asked questions
Why is the incubation period of Andes virus so variable?
The variability (7 to 42 days) reflects several factors: the viral dose received during exposure (the higher the dose, the shorter the incubation), the person's immunity, age, and genetic variability of viral strains. The wide range forces health authorities to maintain surveillance for the maximum known duration, that is 42 days.
Is a person in the incubation period contagious?
For human hantavirus diseases, contagiousness begins with symptom onset. Person-to-person transmission of Andes virus (the only one documented among hantaviruses) does not occur during the asymptomatic incubation phase. That is why contact surveillance relies on screening for symptoms rather than a universal early test.
What happens for MV Hondius passengers?
Passengers and crew disembarked in Tenerife (Granadilla de Abona) on 10 May 2026 are under medical surveillance for 42 days, that is until the end of June 2026. They must monitor their temperature daily, mention their exposure to any consulted healthcare professional, and call 15 (in France) or their local emergency number in case of fever, headache or respiratory symptoms.
Further reading
- About Hantavirus — incubation period — CDC (official documentation)
- WHO — Hantavirus fact sheet — World Health Organization (official documentation)