Wyeomyiae virus: Infectious substances pathogen safety data sheet

Section I – Infectious agent

Name

Wyeomyiae virus

Agent type

Virus

Taxonomy

Family

Peribunyaviridae

Genus

Orthobunyavirus

Species

wyeomyiae^{Footnote 1}

Synonym or cross-reference

Orthobunyavirus wyeomyiae (WYOV) was previously known as Wyeomyia Orthobunyavirus or Wyeomyiae virus^{Footnote 1}. Taiassui virus (TAIAV), Tucunduba virus (TUCV) and Rio Pracupi virus are considered members of the WYOV species^{Footnote 2}.

Characteristics

Brief description

In general, orthobunyaviruses are enveloped and roughly spherical, ranging from 90-110 nm in diameter^{Footnote 3Footnote 4}. The virions are simple in composition, possessing a tripartite, single stranded, negative-sense RNA genome that encodes for four structural proteins^{Footnote 3}. The three genomic segments are designated as small (S), medium (M), and large (L)^{Footnote 3Footnote 4}. The S segment, which measures 1.0 kb, encodes the nucleoprotein, while the M segment, measuring 4.5 kb, encodes the glycoprotein precursor, Gn-Gc. The L segment measures 6.9 kb and encodes for the RNA-dependent RNA polymerase.

Properties

The entry of orthobunyaviruses into susceptible cells relies on interactions between the glycoproteins, Gn and Gc, and cell surface receptors^{Footnote 3}. Upon attachment, the virus will enter the cell through receptor-mediated endocytosis, where acidification of the vesicle will allow for virion uncoating and release of the viral genome to the cytoplasm. There, transcription and translation will take place. Assembly takes place in the Golgi, then the virus moves to the cell surface through the exocytic pathway to be released at the plasma membrane.

Section II – Hazard identification

Pathogenicity and toxicity

Since first reported in 1944, there have only been two documented cases of disease^{Footnote 5Footnote 6}. In the Darien Province in eastern Panama, an adult male worker of a road-surveying company presented with low-grade fever, but made a full recovery^{Footnote 5}. WYOV was detected in his blood. In another case, an 18 month old girl presented with meningoencephalitis symptoms, including fever, headache, vomiting, paresis, and coma^{Footnote 6}. Disease persisted for 2 weeks, ultimately resulting in death^{Footnote 6}. Tucunduba virus, a member of the WYOV species, was isolated from her blood^{Footnote 6}.

In general, upon infection with an orthobunyavirus, patients experience a sudden onset of fever, headache, joint and muscle aches, and occasionally nausea and rash^{Footnote 3}. Symptoms typically persist for about 1 week, but fever may reappear 1–2 weeks later. Most patients recover without long-term sequelae.

Epidemiology

Generally, orthobunyaviruses are maintained in arthropod-vertebrate-arthropod cycles^{Footnote 3}. While the main vector species for WYOV has been identified as Wyeomyia mosquitoes, the vertebrate host range has yet to be determined^{Footnote 7}. WYOV was first identified in Colombia in 1940 after being isolated from Wyeomyia melanocephala mosquitoes^{Footnote 7}. Since then, WYOV has been isolated from mosquitoes in Colombia, Trinidad, Panama, Brazil, and Mexico^{Footnote 7Footnote 8Footnote 9}. In Trinidad, WYOV was recovered from various mosquito species, including Aedes scapularis, Culex amazonensis, Limatus durhamii, Limatus flavisetosus, Trichoprosopon longipes, Psorophora albipes, Psorophora ferox^{Footnote 8}. There have been no large outbreaks of disease as there have only been two cases of infection associated with the WYOV species^{Footnote 5Footnote 6}. These cases occurred in Panama and the Brazilian Amazonian region.

In Trinidad between 1953 and 1966, seroprevalence studies revealed that 8 of 30 human serum samples were protective in neutralization tests, but it is possible that these tests were not specific for WYOV^{Footnote 8}. Neutralizing antibodies have also been detected in the Darien Province in Panama where 10 of 59 residents were positive and in western Panama where 5 of 60 inhabitants were seropositive^{Footnote 5}.

Host range

Natural host(s)

Humans are natural hosts of WYOV^{Footnote 5Footnote 6}. The vertebrate host range has not been determined^{Footnote 7}.

Other host(s)

Mice, rhesus macaques, and opossums have been experimentally infected^{Footnote 10}.

Infectious dose

Unknown.

Incubation period

In humans, the incubation period of orthobunyaviruses ranges from 3 to 8 days^{Footnote 3}.

Communicability

The preferred mode of transmission of WYOV is injection via infected mosquito vectors, mainly Wyeomyia species^{Footnote 7}. Other possible routes of transmission include ingestion and contact with mucous membranes as these have been documented for the related Orthobunyavirus oropoucheense^{Footnote 11}.

Section III – Dissemination

Reservoir

Unknown.

Zoonosis

Unknown.

Vectors

The primary vector of WYOV is Wyeomyia spp. mosquitoes^{Footnote 7}. The virus has also been detected in Aedes scapularis, Culex amazonensis, Limatus durhamii, Limatus flavisetosus, Trichoprosopon longipes, Psorophora albipes, and Psorophora ferox^{Footnote 8}.

Section IV – Stability and viability

Drug susceptibility/resistance

There are no effective antiviral agents against WYOV and orthobunyaviruses in general^{Footnote 3}.

Susceptibility to disinfectants

Common to other enveloped viruses, WYOV can be inactivated by 2% glutaraldehyde, formalin, paraformaldehyde, 1% sodium hypochlorite, hydrogen peroxide, non-ionic surfactants (Tween-20 and Tween-80), ethyl alcohol, isopropyl alcohol, peracetic acid, quaternary ammonium compounds, and iodophor compounds^{Footnote 12Footnote 13}.

Physical inactivation

WYOV was shown to lose virulence when cultured for 30 minutes at 45°C^{Footnote 12}. Other inactivation methods for WYOV are unknown, but have been documented for other members of the Bunyaviricetes class^{Footnote 14Footnote 15}. Based on experiments using Rift Valley Fever virus (RVFV), a gamma radiation dose of 8 Mrads is recommended for safe inactivation of 1 × 10⁶ TCID₅₀ of RVFV^{Footnote 14}. A UV-A radiation energy level of 1000 µW/cm² for 90 minutes and 20 µg/mL of 4'-aminomethyl-trioxsalen (a psoralen) were found to inactivate 10^7.8 TCID₅₀/mL of RVFV^{Footnote 15}. High temperatures of 56°C for 30 minutes or 60°C for 15 minutes were found to inactivate Crimean Congo Hemorrhagic Fever virus (CCHFV)^{Footnote 13}.

Survival outside host

WYOV was shown to retain virulence for 4 days in pure saline and 9 days in serum-saline when refrigerated^{Footnote 10}.

Section V – First aid/medical

Surveillance

Surveillance relies on the detection of neutralizing antibodies through complement-fixation tests and neutralization tests^{Footnote 5}.

Note: The specific recommendations for surveillance in the laboratory should come from the medical surveillance program, which is based on a local risk assessment of the pathogens and activities being undertaken, as well as an overarching risk assessment of the biosafety program as a whole. More information on medical surveillance is available in the Canadian Biosafety Handbook.

First aid/treatment

Treatment for orthobunyaviruses is mainly supportive, and there are no antivirals to treat or prevent disease^{Footnote 3Footnote 16}.

Note: The specific recommendations for first aid/treatment in the laboratory should come from the post-exposure response plan, which is developed as part of the medical surveillance program. More information on the post-exposure response plan can be found in the Canadian Biosafety Handbook.

Immunization

There are no vaccines available for orthobunyaviruses^{Footnote 3Footnote 17}.

Note: More information on the medical surveillance program can be found in the Canadian Biosafety Handbook, and by consulting the Canadian Immunization Guide.

Prophylaxis

There are no known pre-exposure or post-exposure measures available to prevent infection or disease with WYOV^{Footnote 17}.

Note: More information on prophylaxis as part of the medical surveillance program can be found in the Canadian Biosafety Handbook.

Section VI – Laboratory hazard

Laboratory-acquired infections

There is no evidence of laboratory-acquired infections resulting from exposure to WYOV.

Note: Please consult the Canadian Biosafety Standard and Canadian Biosafety Handbook for additional details on requirements for reporting exposure incidents.

Sources/specimens

WYOV may be detected in serum and blood^{Footnote 5}.

Primary hazards

Bites of an infected mosquito vector represent the primary hazard associated with exposure to WYOV^{Footnote 7Footnote 8}.

Special hazards

None.

Section VII – Exposure controls/personal protection

Risk group classification

Orthobunyavirus wyeomyiae is a Risk Group 2 Human Pathogen and Risk Group 2 Animal Pathogen^{Footnote 18}.

Containment requirements

Containment Level 2 facilities, equipment, and operational practices outlined in the Canadian Biosafety Standard for work involving infectious or potentially infectious materials, animals, or cultures.

Protective clothing

The applicable Containment Level 2 requirements for personal protective equipment and clothing outlined in the Canadian Biosafety Standard are to be followed. The personal protective equipment could include the use of a labcoat and dedicated footwear (e.g., boots, shoes) or additional protective footwear (e.g., boot or shoe covers) where floors may be contaminated (e.g., animal cubicles, post mortem rooms), gloves when direct skin contact with infected materials or animals is unavoidable, and eye protection where there is a known or potential risk of exposure to splashes.

Note: A local risk assessment will identify the appropriate hand, foot, head, body, eye/face, and respiratory protection, and the personal protective equipment requirements for the containment zone and work activities must be documented.

Other precautions

A biological safety cabinet (BSC) or other primary containment device to be used for activities with open vessels, based on the risks associated with the inherent characteristics of the regulated material, the potential to produce infectious aerosols or aerosolized toxins, the handling of high concentrations of regulated materials, or the handling of large volumes of regulated materials.

Use of needles and syringes are to be strictly limited. Bending, shearing, re-capping, or removing needles from syringes are to be avoided, and if necessary, performed only as specified in standard operating procedures (SOPs). Additional precautions are required with work involving animals or large-scale activities.

Proper precautions should be considered when working with infected arthropods. This might include implementing a program to prevent escapes and monitor any escaped arthropods, as well as using suitable personal protective equipment (PPE), among other measures^{Footnote 19Footnote 20}.

For diagnostic laboratories handling primary specimens that may contain Orthobunyavirus wyeomyiae, the following resources may be consulted:

• Human Diagnostic Activities Biosafety Guideline
• Local Risk Assessment Biosafety Guideline

Section VIII – Handling and storage

Spills

Allow aerosols to settle. Wearing personal protective equipment, gently cover the spill with absorbent paper towel and apply suitable disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time with disinfectant before clean up (Canadian Biosafety Handbook).

Disposal

All materials/substances that have come in contact with the regulated materials to be completely decontaminated before they are removed from the containment zone or standard operating procedures (SOPs) to be in place to safely and securely move or transport waste out of the containment zone to a designated decontamination area / third party. This can be achieved by using decontamination technologies and processes that have been demonstrated to be effective against the regulated material, such as chemical disinfectants, autoclaving, irradiation, incineration, an effluent treatment system, or gaseous decontamination (Canadian Biosafety Handbook).

Storage

The applicable Containment Level 2 requirements for storage outlined in the Canadian Biosafety Standard are to be followed. Primary containers of regulated materials removed from the containment zone to be labelled, leakproof, impact resistant, and kept either in locked storage equipment or within an area with limited access.

Section IX – Regulatory and other information

Canadian regulatory information

Controlled activities with Orthobunyavirus wyeomyiae require a Pathogen and Toxin licence issued by the Public Health Agency of Canada. Orthobunyavirus wyeomyiae is a terrestrial animal pathogen in Canada; therefore, importation of Orthobunyavirus wyeomyiae requires an import permit under the authority of the Health of Animals Regulations (HAR). The PHAC issues a Pathogen and Toxin Licence which includes a Human Pathogen and Toxin Licence and an HAR importation permit.

The following is a non-exhaustive list of applicable designations, regulations, or legislations:

• Human Pathogens and Toxins Act and Human Pathogens and Toxins Regulations
• Health of Animals Act and Health of Animals Regulations

Last file update

August, 2024

Prepared by

Centre for Biosecurity, Public Health Agency of Canada.

Disclaimer

The scientific information, opinions, and recommendations contained in this Pathogen Safety Data Sheet have been developed based on or compiled from trusted sources available at the time of publication. Newly discovered hazards are frequent and this information may not be completely up to date. The Government of Canada accepts no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information.

Persons in Canada are responsible for complying with the relevant laws, including regulations, directives and standards applicable to the import, transport, and use of pathogens and toxins in Canada set by relevant regulatory authorities, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment and Climate Change Canada, and Transport Canada. The risk classification and related regulatory requirements referenced in this Pathogen Safety Data Sheet, such as those found in the Canadian Biosafety Standard, may be incomplete and are specific to the Canadian context. Other jurisdictions will have their own requirements.

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