Pathogen Safety Data Sheets: Infectious Substances – Monkeypox virus

Pathogen Safety Data Sheet - Infectious Substances

Section I - Infectious Agent

NAME: Monkeypox virus.

Synonym or Cross Reference: MPXV, human monkeypoxFootnote 1Footnote 2Footnote 3Footnote 4Footnote 5

Characteristics: Virus belongs to family Poxviridae, sub-family Chordopoxvirinae and genus OrthopoxvirusFootnote 1Footnote 4Footnote 5. MPXV is a 200 to 250 nm brick- shaped enveloped virus with characteristic surface tubules and a dumbbell-shaped core componentFootnote 4. The MPXV genome consists of linear double-stranded DNA. Monkeypox virus is antigenically related to the variola and vaccinia virusesFootnote 6.

Section II – Hazard Identification

Pathogenicity/Toxicity: The disease is characterised by the onset of non- specific symptoms which can include fever, headache, backache, lymphadenopathy and fatigue during a prodromal period of 2 to 3 daysFootnote 1Footnote 2Footnote 4Footnote 7. This is followed by a 2 to 4 week period in which a rash develops and progresses from macules, to papules, to vesicles, and then to pustules, followed by umbilication, scabbing and desquamationFootnote 4Footnote 5Footnote 8. The rash usually occurs in a centrifugal distribution, often spreading to the palms and soles of the feetFootnote 4. Lesions can also develop on mucous membranes, conjunctivae, in the mouth, on the tongue, and on the genitaliaFootnote 5. The clinical presentation of monkeypox is similar to that of smallpox except for the pronounced lymphadenopathy associated with monkeypox and generally milder symptomsFootnote 6Footnote 9. Lymphadenopathy is thus considered a key distinguishing feature of monkeypoxFootnote 5Footnote 9Footnote 10. The case fatality rate is approximately 1 to 10% in Africa, with higher death rates among young childrenFootnote 4Footnote 8. In children unvaccinated against smallpox, the case-fatality rate ranges from 1% to 14%Footnote 9Footnote 10.

Epidemiology: Monkeypox affects all age groups; however, children under 16 years of age have constituted the greatest proportion of casesFootnote 9 . The virus occurs naturally in West and Central Africa in the vicinity of tropical junglesFootnote 4. MPXV isolates originating from West Africa appear to be less virulent and/or transmissible to humans and non-human primates than those from the Congo Basin in Central Africa. Furthermore, the cessation of smallpox vaccination appears to have increased the susceptibility of humans to severe monkeypox.

In 1970, the first human case of monkeypox was identified in a 9 month old child in the Democratic Republic of the Congo (formerly Zaire) in a region where smallpox was eradicated in 1968Footnote 6Footnote 8Footnote 11. In the following year, six additional cases of human monkeypox infection were reported in Liberia, Sierra Leone and NigeriaFootnote 12. From 1970 to 1979, 47 human cases of monkeypox were identified, 38 of which were from ZaireFootnote 4Footnote 5. In the Democratic Republic of the Congo, a total of 338 cases were reported between 1981 and 1986, and more than 400 cases were reported between February 1996 and October 1997Footnote 13Footnote 14.

In 2003, the first cases of human monkeypox in the western hemisphere were reported after an outbreak was reported in Midwestern United States (Illinois, Indiana, Kansas, Missouri, Ohio and Wisconsin) due to the importation of MPXV-infected West African rodents from GhanaFootnote 1Footnote 4Footnote 7Footnote 8Footnote 15.

Host Range: Humans, squirrels, non-human primates, black-tailed prairie dogs, African brush-tailed porcupines, rats, and shrewsFootnote 1Footnote 2Footnote 3Footnote 4Footnote 5Footnote 7Footnote 8Footnote 11Footnote 13Footnote 14Footnote 15Footnote 16.

Infectious Dose: Unknown.

Mode of Transmission: MPXV is transferred from infected animals through a bite or through direct contact with the infected animal's blood, body fluids, or lesionsFootnote 2Footnote 5Footnote 7Footnote 8. It can also be transferred from human-to-human via the respiratory tract, by direct contact with body fluids of an infected person, or with virus-contaminated objectsFootnote 5Footnote 7Footnote 10Footnote 17. The rate of person-to person transmission is increasing, with a secondary attack rate of approximately 10%Footnote 4Footnote 10.

Incubation Period: Approximately 7 to 17 daysFootnote 4Footnote 8.

Communicability: MPXV is capable of person-to-person transmission; a chain of up to six sequential human-to-human transmission events has been documentedFootnote 4Footnote 5Footnote 14.

Section III - Dissemination

Reservoir: Not fully understood but arboreal squirrels (Funisciurus spp., and to a lesser degree, Heliosciurus spp.) are believed to be a reservoir for MPXVFootnote 4Footnote 6Footnote 13Footnote 16.

Zoonosis: YesFootnote 1Footnote 2Footnote 4Footnote 5Footnote 6Footnote 7Footnote 8Footnote 9Footnote 11Footnote 13Footnote 14Footnote 15Footnote 16Footnote 18.

Vectors: UnknownFootnote 4.

Section IV - Stability and Viability

Drug Susceptibility: Cidofovir is considered as a potential therapeutic agent for MPXV infections, as it has been shown to have activity against many DNA viruses in vitro, including MPXVFootnote 19.

Susceptibility to Disinfectants: Orthopoxviruses are susceptible to 0.5% sodium hypochlorite, chloroxylenol-based household disinfectants, glutaraldehyde, formaldehyde, and paraformaldehydeFootnote 20Footnote 21.

Physical Inactivation: Orthopoxviruses are inactivated by heat (autoclaving and incineration)Footnote 20Footnote 21.

Survival Outside Host: Orthopoxviruses are stable at ambient temperatures when driedFootnote 17.

Section V – First Aid / Medical

Surveillance: Monitor for symptoms (unexplained fever, rash or prominent lymphadenopathy) and confirm by laboratory diagnosis using virus isolation, PCR-based assays, haemagglutination inhibition assays, electron microscopy, ELISA, Western blotting, or immunohistochemistryFootnote 4Footnote 5Footnote 6Footnote 7Footnote 8Footnote 10Footnote 16Footnote 18.

Note: All diagnostic methods are not necessarily available in all countries.

First aid/Treatment: There are no licensed antiviral drugs available to treat MPXV infection; instead, treatment is supportiveFootnote 5.

Immunization: Vaccination with vaccinia virus (smallpox vaccine) is approximately 85% effective against monkeypoxFootnote 4Footnote 17.

Prophylaxis: Vaccination with the smallpox vaccine, within 4 days and up to 14 days after initial contact with a confirmed monkeypox caseFootnote 5Footnote 17.

Section VI - Laboratory Hazards

Laboratory-Acquired Infections: None reported to dateFootnote 17.

Sources/Specimens: Lesion fluids or crusts, respiratory secretions, and tissues of infected hostsFootnote 5Footnote 16Footnote 17.

Primary Hazards: Ingestion, parenteral inoculation, droplet or aerosol exposure of mucous membranes or broken skin, or contact with infectious fluids or tissuesFootnote 10Footnote 17.

Special Hazards: Bite of infected non-human primates or rodents, or objects contaminated with the virus (e.g. bedding, clothing)Footnote 1. In pregnant women, human monkeypox may cause fetal complicationsFootnote 24.

Section VII – Exposure Controls / Personal Protection

Risk Group Classification: Risk Group 3Footnote 22.

Containment Requirements: Containment Level 3 facilities, equipment, and operational practices for work involving regulated infectious materials, animals, or cultures.

Protective Clothing: Personnel entering the laboratory should remove street clothing and jewellery, and change into dedicated laboratory clothing and shoes, or don full coverage protective clothing (i.e., completely covering all street clothing). Additional protection may be worn over laboratory clothing when infectious materials are directly handled, such as solid-front gowns with tight fitting wrists, gloves, and respiratory protection. Eye protection must be used where there is a known or potential risk of exposure to splashesFootnote 23.

Other Precautions: All activities with infectious material should be conducted in a biological safety cabinet (BSC) or other appropriate primary containment device in combination with personal protective equipment. Centrifugation of infected materials must be carried out in closed containers placed in sealed safety cups, or in rotors that are loaded or unloaded in a biological safety cabinet. The use of needles, syringes, and other sharp objects should be strictly limited. Open wounds, cuts, scratches, and grazes should be covered with waterproof dressings. Additional precautions should be considered with work involving animals or large scale activitiesFootnote 23.

Additional Information

For clinical diagnostic laboratories handling patient specimens that may contain MPXV, the following resources may be consulted:

Section VIII - Handling and Storage

SPILLS: Allow aerosols to settle and, wearing protective clothing, gently cover spill with paper towels and apply suitable disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up (30 min)Footnote 23.

Disposal: Decontaminate all materials for disposal by steam sterilization, chemical disinfection, and/or incinerationFootnote 23.

Storage: In sealed containers that are appropriately labelled and locked in a Containment Level 3 facilityFootnote 23.

Section IX – Regulatory and Other Information

Regulatory Information: MPXV is a Security Sensitive Biological Agent (SSBA). There are additional security requirements, such as obtaining a Human Pathogens and Toxins Act Security Clearance, for work involving SSBAs.

The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.

Date Updated: May 2022

Prepared By: Centre for Biosecurity, Public Health Agency of Canada.

Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.

Copyright ©
Public Health Agency of Canada, 2022


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