The Management of Viral Haemorrhagic Fevers in Ireland - Health ...

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Data evaluating transmission by the airborne route are scarce but the possibility of such transmission remainsin rare instances from patients in advanced stages of disease. 1,6 There is also a potential risk to laboratoryworkers as small clouds of aerosolized viruses can be released in laboratory accidents, such as breakage ofcontainers within centrifuges.H.4.1 Cases with unexplained routes of transmissionIn most outbreaks of VHF, the exposures and routes of transmission have been established for most cases.However, there are some instances where airborne or droplet transmission was a possibility.• In June 2009, a nosocomial outbreak of CCHF involving 6 cases occurred in Iran, four of which werehealthcare workers. Two cases were infected by percutaneous exposure, and three others were probablyinfected through direct contact with blood, clothes and bed sheets. Of these three contacts, one wasadmitted to the same bed as the index case before it had been thoroughly disinfected; one was exposed tothe blood of the index cases while wearing perforated gloves; and the third had always worn intact gloveswhile caring for the index case, but did not always use a face shield or surgical mask and eye protection. 16• The first case of patient to patient nosocomial transmission of CCHF was described in 2006. The secondarycase was in a patient who had shared a room with the index case for 5 days before CCHF was diagnosed.The secondary case was considered to have a nosocomial infection as she had been in hospital for 30 daysbefore the index case was admitted (incubation period of CCHF: 3-5 days). It is not known for certain how thesecondary case became infected but it is postulated that it could have been through contact with infectedblood or bodily fluids as the two patient shared the same toilet. Airborne transmission was considered aremote possibility. 17• Follow-up of contacts (n=157) of a symptomatic patient with Lassa fever who arrived by air in Germany inJanuary 2000 revealed one probable secondary case. This person was a physician who had inserted anintravenous line, obtained blood samples and administered an infusion, did not wear gloves or a maskbut couldn’t recall contamination of the skin with the patient’s blood. The doctor was also exposed to acough from the patient during a throat examination. There was no evidence of any other possible routes oftransmission. This probable secondary case was serological positive but was never symptomatic. 18H.4.2 Laboratory accidentsAirborne transmission is not thought to be the dominant route of transmission for VHFs, with the exception ofmechanical aerosolisation during medical or laboratory procedures. Arenaviruses are transmitted to humansby the inhalation of small particle aerosols derived directly from rodent excreta or saliva containing the virusand these viruses pose a particular risk to laboratory workers where techniques present an opportunity for theaerosolisation of the virus. 19 There have been two reported cases of laboratory-acquired Brazilian HF (Sabiavirus). The first was a laboratory technician who was infected during studies to characterise the virus, probablyby aerosol 20 , and the second was a virologist in Yale, US, who was infected following a leak in a high-speedcentrifuge. 21 Aerosol transmission is also the suspected source in six cases (one death) of Machupo virus up to1980. 22Transmission by aerosolisation in the laboratory and by needlestick injury has also been documented for OmskHF, a member of the flaviviruses. 23 Up to 1979, 87 cases of laboratory-acquired infections of Kyasanur ForestDisease were reported, with inhalation of aerosols during cultivation the most frequently reported route of24, 25transmission.Appendix H: Review of evidence for mode of transmission The Management of Viral Haemorrhagic Fevers in Ireland/HPSC 2012H.4.3 Transmission from non-human primatesAn outbreak investigation into a combined Simian haemorrhagic fever and Ebola virus infection amongcynomolgus monkeys at a primate quarantine facility in Reston, Virginia, United States, in 1989 suggested thatthe route of transmission between animals was aerosol or droplet, though there were no specific studies wereconducted at the time to investigate this feature. Other observations relating to the mode of transmission ofEbola virus during the outbreak included: direct contact was not necessary; blood transfer was not essential;throat swabs were often positive for Ebola virus and the virus was cultured repeatedly from urine and faeces. 26Johnson et al. (1995) reported aerosol transmission of Ebola virus to non-human primates in an experimentalprimate model. 27- 87 -
In April 1990, CDC reported on filovirus infections among persons with occupational exposure to non-humanprimates. Antibody to one or more filovirus antigens was detected in six of 178 persons tested. Four of the sixshowed serologic evidence of recent infection, all of whom worked as animal handlers. One person is likely tohave been infected when he lacerated his finger while performing an autopsy of a dead animal. The mode oftransmission is unknown for the other three. The other two persons had evidence of past infections and hadregular contact with non-human primates over a number of years. 28 In an update in June, 1990, it was reportedthat seropositivity to one or more filovirus test antigens was not evenly distributed between staff groups; 9.8%(26/266) of staff at the import quarantine facility tested positive compared with 5.6% (16/284) of staff whoworked with monkeys (or monkey tissues/bodily fluids) outside the quarantine facility. This compares with 2.7%(12/449) of samples randomly selected from a cross-sectional adult primary-care outpatient population. Noneof the 42 staff who tested positive reported any illness likely to have been caused by a filovirus. 29This is in contrast to other reports on animal handlers. Hennesson W reported that during the Marburg virusoutbreak of 1967 none of the animal caretakers in Marburg, Frankfurt or Belgrade who were not in contact withblood became ill, nor did those who took the usual precautions when working with viruses. The proportion ofthose who became ill varied with occupational exposure; 68.9% (20/29) staff with exposure to blood becameill compared with 30.7% (4/13) of staff who were exposed to tissue cultures. 30The only case of Côte d’Ivorie Ebola virus was in a veterinarian who performed an autopsy on an infectedchimpanzee. The chimpanzee was part of a troop that had been studied since 1987. The autopsy was performedfollowing the sudden death of 12 members of the troop. 31Appendix H: Review of evidence for mode of transmission The Management of Viral Haemorrhagic Fevers in Ireland /HPSC 2012- 88 -
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The Management ofViral Haemorrhagic
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3.5 Infection prevention and contro
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The Viral Haemorrhagic Fever Sub-Co
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• As soon as VHF is being conside
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BackgroundIntroductionViral haemorr
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The search strategy for these guide
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1.3 Overview of VHFsVHFs share a nu
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1.6 Marburg haemorrhagic feverMarbu
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1.9 FlavivirusesThe flaviviruses ca
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1.10 Requirement to notify VHF to t
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Table 3. Clinical presentation of C
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Patient Risk Assessment Key Points
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2.4 Initial management of patient c
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If the malaria test is positive:•
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3. Infection Prevention and Control
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Page 37 and 38: - All acute hospitals should have a
Page 39 and 40: 3.7 Infection prevention and contro
Page 41 and 42: - For larger spills, cover the area
Page 43 and 44: 3.8 Handling human remainsThe gener
Page 45 and 46: 4.3 Packaging and transport of biol
Page 47 and 48: 4.5 Laboratory testing for High Ris
Page 49 and 50: 5. Public Health Management of Impo
Page 51 and 52: In the case of suspected Lassa feve
Page 53 and 54: Box 1Risk CategorisationCasual/no-r
Page 55 and 56: 5.4.4 Management of contactsThis is
Page 57 and 58: 5. Public Health Management of Impo
Page 59 and 60: Figure 3 Summary of notification pr
Page 61 and 62: should be identified in a bid to av
Page 63 and 64: The procedure for cleaning and disi
Page 65 and 66: 1. covert release of a biological a
Page 67 and 68: References1. Scientific Advisory Co
Page 69 and 70: 55. Department of Health and Childr
Page 71 and 72: Appendix A: Search Strategies for V
Page 73 and 74: Appendix C: Published Reports on Re
Page 75 and 76: available 24 hours a day to answer
Page 77 and 78: coughing. They advise that the stag
Page 79 and 80: This was the first highly pathogeni
Page 81 and 82: Appendix D: Annex 2: Decision Instr
Page 83 and 84: Has the patient...Clinical Risk Ass
Page 85 and 86: Appendix G: Summary of VHF Risk Cat
Page 87: longer thus increasing the risk of
Page 91 and 92: 24. CDC Special Pathogens Branch. K
Page 93 and 94: Appendix J: VHF Risk Assessment for
Page 95 and 96: Malaria Test Results:Malaria test 1
Page 97 and 98: Port of Arrival:Name:Via:Arrived by
Page 99 and 100: VHF Case Exposure Assessment & Cont
Page 101 and 102: Healthcare workers:1234567891011121
Page 103 and 104: Total number of contactsVHF Case Ex
Page 105 and 106: Category of worker:CleanerDoctorIf
Page 107 and 108: Relationship to case:PassengerIf ot
Page 109 and 110: Are you currently well?Have you fev
Page 111 and 112: VHF High Risk Contact Surveillance
Page 113 and 114: VHF High Risk Contact Surveillance
Page 115 and 116: Appendix O:VHF Checklists of action
Page 117 and 118: Appendix P:Campus Map, Mater Miseri
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