Hantavirus - Serology and PCR

Consistent with O. Reg. 671/92 of the French Language Services Act, laboratory testing information on this page is only available in English because it is scientific or technical in nature and is for use only by qualified health care providers and not by members of the public.

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.

*Uncontrolled print copy. Valid only on day of print: 26 March 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, relevant clinical information or approvals (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	Serum	5.0 mL blood or 1.0 mL serum	Red top or Serum Separator tubes (SST)
Hantavirus PCR	General Test Requisition	Serum	5.0 mL blood or 1.0 mL serum	Red top or Serum Separator tubes (SST)
Hantavirus PCR	General Test Requisition	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	CSF and other body fluids	0.5 mL	Sterile container Sterile 1.5-2.0 mL screw cap tubes.
Hantavirus PCR	General Test Requisition	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

Complete all fields of the General Test Requisition

Test(s) requested and indications for testing.
Patient setting/specimen source
History of contact with wild or domestic rodents or their excrement (e.g.
droppings/urine) and if the rodents have confirmed Hantavirus infection
Full travel history including travel destinations, dates and relevant exposures.
Symptoms and symptom onset date, clinical diagnosis, underlying diseases, exposure
risk, specific clinical syndrome suspected (HFRS or HPS)

For clinical specimens, 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. Comprehensive patient history must be provided; samples lacking sufficient patient history to justify testing may be rejected.

If additional infectious disease testing is required, a separate tube must be submitted for hantavirus testing. All tests (hantavirus and non-hantavirus tests) can be listed on one PHO Laboratory requisition.

NOTE: Both Serology and Molecular testing by PCR are not performed routinely and must be approved by a PHO Microbiologist. Contact PHO’s laboratory customer service at 416-235-6556 or 1-877-604-4567 to request approval.

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

Place specimen in biohazard bag and seal. Specimens should be stored at 2-8°C following collection and shipped to PHO’s laboratory on ice packs.

Specimens for molecular testing should be frozen and shipped on dry ice.

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.

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

All clinical specimens must be shipped in accordance to the Transportation of Dangerous Good Act.

Special Instructions

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

Hantaviruses are Risk Group 3 pathogens and PHO Laboratory will not aliquot or perform other testing until it has been ruled out by the National Microbiology Laboratory (NML).

If additional infectious disease testing is needed alongside hantavirus testing, submit one requisition with separate specimens/tubes and notify laboratory staff that the patient is under investigation for Hantavirus.

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).

The turnaround time for both serology and PCR is up to 28 business days from receipt at PHO’s laboratory.

Test Methods

Hantavirus testing at the NML 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).

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. 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.

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 (13th ed). ASM Press. Washington DC, USA. 1917-1931.