Table 2: Incubation period, mode of transmission and period of communicability of VHFs Disease Incubation Mode of transmission Period of communicability Crimean-Congo Usually 1–3 Tick bite or crushing tick. Health care At least for duration of illness. haemorrhagic days (1–12 workers frequently infected by exposure fever days) to blood and secretions from cases. Haemorrhagic 2–4 weeks Aerosol from infected rodent excreta Not well defined: fever with renal (few days to (urine, respiratory secretions, saliva, transmission is rare. syndrome 2 months) faeces). Hantavirus 2 weeks Aerosol from infected rodent excreta Not well defined: pulmonary (few days to (urine, respiratory secretions, saliva, transmission is rare. syndrome 6 weeks) faeces). Lassa fever 6–21 days Aerosol or direct contact with excreta of Virus present in throat during infected rats (commonly eaten). acute febrile phase, in urine injury. Contact with case’s for 3–9 weeks and in semen pharyngeal secretions or urine. Sexual for 3 months after infection. contact. Marburg, Ebola 2–21 days handling dead animals in the Low risk in incubation period. rainforest or the blood and tissues of Highest in late stages of infected monkeys. Person-to-person illness. Cadaver can be spread through infected blood, infectious. May be passed secretions, organs, semen and through up to 7 weeks contaminated needles. after illness. Management of case Investigation Obtain a history of travel, contact with animals, insect bites, possible contacts with infected cases, needle-stick accidents, occupation, recreational activities and any other at-risk activities. Ensure laboratory confirmation has been attempted. Restriction In health care facilities, the following isolation precautions are indicated: Crimea-Congo haemorrhagic fever: contact isolation haemorrhagic fever with renal syndrome: standard precautions hantavirus pulmonary syndrome: standard precautions Lassa fever: droplet and contact isolation Marburg, Ebola: contact isolation.
Table 2: Incubation period, mode of transmission and period of communicability of VHFs Disease Incubation Mode of transmission Period of communicability Crimean-Congo haemorrhagic fever Usually 1–3 days (1–12 days) Tick bite or crushing tick. Health care workers frequently infected by exposure to blood and secretions from cases. At least for duration of illness. Haemorrhagic fever with renal syndrome 2–4 weeks (few days to 2 months) Aerosol from infected rodent excreta (urine, respiratory secretions, saliva, faeces). Not well defined: transmission is rare. Hantavirus pulmonary syndrome 2 weeks (few days to 6 weeks) Aerosol from infected rodent excreta (urine, respiratory secretions, saliva, faeces). Not well defined: transmission is rare. Lassa fever 6–21 days Aerosol or direct contact with excreta of infected rats (commonly eaten). injury. Contact with case’s pharyngeal secretions or urine. Sexual contact. Virus present in throat during acute febrile phase, in urine for 3–9 weeks and in semen for 3 months after infection. Marburg, Ebola 2–21 days handling dead animals in the rainforest or the blood and tissues of infected monkeys. Person-to-person spread through infected blood, secretions, organs, semen and contaminated needles. Low risk in incubation period. Highest in late stages of illness. Cadaver can be infectious. May be passed through up to 7 weeks after illness. Management of case Investigation Obtain a history of travel, contact with animals, insect bites, possible contacts with infected cases, needle-stick accidents, occupation, recreational activities and any other at-risk activities. Ensure laboratory confirmation has been attempted. Restriction In health care facilities, the following isolation precautions are indicated: Crimea-Congo haemorrhagic fever: contact isolation haemorrhagic fever with renal syndrome: standard precautions hantavirus pulmonary syndrome: standard precautions Lassa fever: droplet and contact isolation Marburg, Ebola: contact isolation.
communicable-disease-control-manual-2012.docx