Hantavirus - Serology and PCR

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Background
This page provides information on the Serology and PCR testing offered through Public Health Ontario (PHO) for hantaviruses.

Hantaviruses are RNA viruses that belong to the Hantaviridae family¹.
These are zoonotic viruses that can be transmitted to humans through contact with infected (but asymptomatic) rodents or their excreta (urine, feces, or saliva).

Hantaviruses are associated with two clinical syndromes with varying disease courses:

Hantavirus Pulmonary Syndrome (HPS) or
Hemorrhagic Fever with Renal Syndrome (HFRS)

Different hantaviruses are associated with HPS and HFRS and the severity of disease caused can be variable. Considerations for disease epidemiology and exposure history should be made if hantavirus infection is suspected^2,3. Testing is available for both syndromes at the National Microbiology Laboratory (NML) in Winnipeg.

Updates
Effective July 2, 2025, submission of the new Vector-borne and Zoonotic Virus Testing Intake Form is mandatory, along with the General Test Requisition when requesting specific vector-borne or zoonotic virus tests. The new intake form replaces both the Arbovirus (Non-Zika) Testing Intake Form and the Mandatory Intake Form for Zika Virus Testing.

* Copie d'impression non contrôlée. Valide uniquement le jour de l'impression : 05 juill. 2025.

Testing Indications

Note: A clinical risk assessment for hantavirus infection is recommended prior to submitting a test request. Due to laboratory biosafety concerns, testing for other infectious diseases that are ordered/sent to PHO at the same time will not be performed until hantavirus testing is completed by the NML.

Hantavirus testing is performed at the NML. All requests require approval by a PHO Microbiologist. A review of the individual’s clinical status, exposure, and travel history (including relevant dates) and consideration of alternative diagnoses should be completed prior to submitting a test request to PHO. This information will be required for the approval processes.

The following individuals may be considered for hantavirus testing:

New onset of compatible symptoms following recent exposure to rodents, their excrement, bedding/nesting materials or saliva (e.g. febrile illness, cough, shortness of breath, bilateral pneumonia (HPS); or febrile illness, hemorrhagic manifestations (HFRS), among others).
Hantavirus exposures may occur at home, in the workplace, in rural areas or outdoors while participating in seasonal activities. The incubation period is between 2 to 8 weeks post-exposure⁴.

Individuals with compatible symptoms who have recently traveled to or reside in areas with a risk for HPS^2,3 or HFRS⁴ and have relevant rodent exposures.
In Canada, most cases of HPS have occurred in Quebec, Manitoba, Saskatchewan, Alberta and British Columbia^2,3. HPS cases have also been detected elsewhere in the Americas⁴. Cases of HFRS are typically reported in Europe and Asia⁴, with sporadic cases previously identified in the US and Canada among rat breeders/owners⁵.

Other clinical situations where hantavirus testing may impact patient management.
Situations not identified above require discussion with a PHO Microbiologist.

Serology is the preferred method for hantavirus testing. Test requests with insufficient justification based on the indications above may be cancelled. This includes requests for hantavirus PCR without an accompanying request for hantavirus serology. Testing is not recommended for asymptomatic individuals.

Acceptance/Rejection Criteria

Specimens received without the appropriate forms (See: Submission and Collection Notes) are subject to cancellation.

Specimen Collection and Handling

Specimen Requirements

Test Requested	Required Requisition(s)	Specimen Type	Minimum Volume	Collection Kit
Hantavirus Serology	General Test Requisition Vector-borne and Zoonotic Virus Testing Intake Form	Serum	5.0 mL blood or 1.0 mL serum	Red top or Serum Separator tubes (SST)
Hantavirus PCR	General Test Requisition Vector-borne and Zoonotic Virus Testing Intake Form	Serum	5.0 mL blood or 1.0 mL serum	Red top or Serum Separator tubes (SST)
Hantavirus PCR	General Test Requisition Vector-borne and Zoonotic Virus Testing Intake Form	Whole blood	1.5 mL blood	EDTA, heparin or citrate tubes (can be submitted as aliquots in sterile 1.5 – 2.0 mL screw cap tubes).
Hantavirus PCR	General Test Requisition Vector-borne and Zoonotic Virus Testing Intake Form	CSF and other body fluids	0.5 mL	Sterile container Sterile 1.5-2.0 mL screw cap tubes.
Hantavirus PCR	General Test Requisition Vector-borne and Zoonotic Virus Testing Intake Form	Tissues	n/a	Fresh or frozen tissues- Sterile container Formalin-fixed tissues- place in sterile plastic containers, clearly identified as being in formalin. Paraffin embedded tissues- can be sent as entire blocks or 4-6 µm sections in a plastic tube or vial.

Submission and Collection Notes

Label the specimen container(s) with the patient’s first and last name, date of collection, and one other unique identifier such as the patient’s date of birth or Health Card Number. For additional information see: Criteria for Acceptance of Patient Specimens. Failure to provide this information may result in rejection or testing delay

Each specimen submitted for testing must be accompanied by a separate PHO General Test Requisition, with all fields completed.

It is MANDATORY to provide the clinical information, relevant travel(s), and relevant exposures for Zoonotic viruses requested on the Vector-borne and Zoonotic Virus Testing Intake Form. Test requests that are submitted without the appropriate mandatory information are subject to cancellation.

Testing for Hantavirus is not routinely performed and must be approved by a PHO Microbiologist. Submission of the mandatory Vector-borne and Zoonotic Virus Testing Intake Form will initiate the review process at PHO provided the form contains all necessary information. Requests received without the form, forms submitted with insufficient information or insufficient justification for testing are subject to cancellation.

If additional infectious disease testing is required, requests for hantavirus serology require the submission of a separate tube of blood. If testing for other infectious diseases is required at the same time, ensure that the hantavirus collection is made in a separate tube. Notify laboratory staff, both at your local microbiology laboratory and PHO that the patient is under investigation for Hantavirus. All tests (Hantavirus and non-Hantavirus tests) can be listed on one PHO requisition.

Due to potential biosafety risks, PHO will not aliquot or perform other testing until hantaviruses have been ruled out by the National Microbiology Laboratory (NML).

Timing of Specimen Collection

Serology:
Acute and convalescent sera should be collected for serologic testing, where applicable. The convalescent serum specimen should be collected at least 2 to 3 weeks after the initial specimen.

Molecular (PCR):
Specimens submitted for molecular testing (PCR) should be collected ASAP after the onset of symptoms (within 3 to 10 days⁶), unless otherwise indicated via discussion with a PHO Microbiologist.

Limitations

Haemolysed, icteric, lipemic or microbial contaminated sera or plasma are not recommended for testing.

Storage and Transport

Specimens should be transported according to TDG guidelines for Category A pathogens (UN2814 packaging).

All clinical specimens must be shipped in accordance with the Transportation of Dangerous Goods Act/Regulations.

Place each specimen type in an individual biohazard bag and seal. Insert the corresponding requisition in the pocket on the outside of each sealed biohazard bag.
Clotted blood/serum specimens should be stored at 2-8°C following collection and shipped to PHO on ice packs.
Ship refrigerated specimens (e.g., clotted blood, serum, CSF) on ice packs, and frozen specimens (e.g., serum, CSF, tissues) on dry ice. Do not ship clotted blood, EDTA/ heparin/citrated whole blood on dry ice.

All specimens submitted for molecular testing should be stored at 2-8°C following collection and shipped to PHO on ice packs. For CSF and serum, If a delay in transport to PHO is anticipated (more than 72 hours), specimens should be frozen (at -80°C if possible) and shipped on dry ice.

Centrifugation of serum tubes is not needed and should be avoided.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Hantavirus serology and molecular (PCR) testing is referred out to the National Microbiology Laboratory (NML).

Turnaround time for both serology and PCR is up to 28 business days from receipt at PHO.

Test Methods

Hantavirus testing will depend on the patient’s clinical presentation and epidemiological risk factors for HPS/HFRS indicated at the time of submission.

Serology:
Hantavirus serology (IgM/IgG) is performed at the NML by enzyme linked immunosorbent assay (ELISA) or strip immunoassay as appropriate for select HPS or HFRS-associated viruses (e.g. Sin Nombre or Seoul virus).

Molecular (PCR):
Molecular testing is performed at the NML by PCR (quantitative and gel-based). Positive results may be confirmed via Sanger sequencing as appropriate.

Interpretation

Hantavirus testing at the NML may be performed by a method that is not fully validated/verified. Refer to NML-Guide to Services for further information.

All results should be interpreted in the context of the clinical and epidemiological information available.

Serology*

IgM ELISA Result	IgG ELISA Result	Possible Interpretation and Recommendations
Negative	Negative	Anti-hantaviral antibodies not detected. This does not rule out infection. Submit a second specimen for testing if clinically indicated unless a PCR test has also been performed and the result for the hantavirus gene targets are negative or not detected.
Positive	Negative	Anti-hantaviral IgM antibodies detected. This suggests an acute/recent infection. Cross-reactivity with other viral agents may be possible. Submit a convalescent specimen for testing.
Negative	Positive	Anti-hantaviral IgG antibodies detected. This suggests a past hantavirus infection or potential cross-reactivity. Submit a second specimen for testing if clinically indicated.
Positive	Positive	Anti-hantaviral IgM and IgG antibodies detected. Suggestive of an acute or recent infection. Submit a convalescent specimen for testing.
Equivocal	Equivocal	Unable to determine if anti-hantaviral antibodies were present. Submit an additional specimen for testing within 2 to 3 weeks of the initial specimen collection date.

Molecular (PCR)*

PCR Result	Possible Interpretation and Recommendations
Negative	Hantavirus nucleic acids not detected. This does not exclude infection. Serology testing is recommended if there is a strong clinical suspicion of hantavirus infection.
Positive	Hantavirus nucleic acids detected. This suggests an acute infection.
Equivocal	Unable to determine the presence of hantavirus nucleic acids in the specimen. This may represent an acute infection (low level viremia) or a false positive. Submit an additional specimen for testing.
Invalid	Testing unable to be completed due to a quality issue. Submit an additional specimen for testing if clinically indicated.

* Reviewed in collaboration with the NML

Reporting

Results are reported to the ordering physician, authorized health care provider (General O. Reg 45/22, s.18) or submitter as indicated on the requisition.

Positive results are also reported to the Medical Officer of Health as per Health Protection and Promotion Act.

References

Bradfute, S. B., Calisher, C. H., Klempa, B., Klingström, J., Kuhn, J. H., Laenen, L., Tischler, N. D., & Maes, P. 2024. ICTV Virus Taxonomy Profile: Hantaviridae 2024, J. Gen. Virol. 105: 001975.
Warner BM, Dowhanik S, Audet J, Grolla A, Dick D, Strong JE et al. 2020. Hantavirus cardiopulmonary syndrome in Canada. Emerg. Infect. Dis. 26(12): 3020-3024.
Drebot MA, Jones S, Grolla A, Safronetz D, Strong JE, Kobinger G, et al. 2015. Hantavirus pulmonary syndrome in Canada: An overview of clinical features, diagnostics, epidemiology and prevention. CCDR. 41-6: 124-130.
Pan American Health Organization (PAHO). 199. Hantavirus in the Americas: Guidelines for diagnosis, treatment, prevention and control (Technical paper No. 47). Washington DC, USA.
Kerins JL, Koske SE, Kazmierczak J, Austin C, Gowdy K, Dibernardo A et al. 2018. Outbreak of Seoul Virus Among Rats and Rat Owners — United States and Canada, 2017. MMWR. 67(4): 131-134.
Klena JD, Chiang CF, Whitmer SM, Wang YF, Shieh WJ. 2023. Hantaviruses. In: Carroll KC, et al. 2023. Manual of Clinical Microbiology (13^thed). ASM Press. Washington DC, USA. 1917-1931.

* Copie d'impression non contrôlée. Valide uniquement le jour de l'impression : 05 juill. 2025.

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Mis à jour le 2 juill. 2025