Testing for Legionella, Mpox and Mumps

Legionella

Legionnaires’ disease is increasing in frequency as the climate changes. In addition to diagnostic and treatment relevance, testing for legionella can help Public Health in investigating and addressing environmental sources of Legionella. For patients presenting with pneumonia like symptoms (e.g., cough, shortness of breath, fever, malaise), where Legionella is on the differential, the recommended testing is both of the following:

• Lower respiratory sample (e.g., sputum) for Legionella culture, AND
• Legionella urinary antigen test

Obtaining a lower respiratory sample for Legionella culture in addition to urinary antigen test is of particular importance. The Legionella urinary antigen test only detects Legionella pneumophila serogroup 1, whereas Legionella culture can detect other serogroups of Legionella pneumophila or other species of Legionella. Additionally, culture isolates can be typed and potentially linked to other cases and environmental sources. Ideally, respiratory samples should be obtained before antibiotic therapy is started.

Testing for Legionella is not recommended for asymptomatic individuals.

For more information on Legionella testing, please see Elab Handbook.

Mpox testing and vaccination

The British Columbia Mpox outbreak was declared over in January 2023. Most cases were among gay, bisexual, or other men who have sex with men. New cases can still result from travel or limited local exposure. Anyone can become exposed or infected after close contact.

The classic Mpox clinical presentation is divided into a prodromal and acute phase. The prodromal phase is characterized by lymphadenopathy, malaise and fever. This is followed by the acute phase, characterized by a painful rash typically involving the oral, inguinal or perianal areas.

Patients who have received Mpox vaccine may present with atypical symptoms such as less intense rash or proctitis alone with no rashes. Clinicians should continue to consider Mpox in their differential diagnosis. If there is localized pain/swelling in regions such as the throat or rectum but no evidence of skin lesions, collect a swab in or around the affected area with an oropharyngeal or a rectal swab.

Testing for Mpox is not recommended for asymptomatic individuals

The Mpox vaccine has been available to at risk populations in British Columbia since June 2022. For more information on eligibility and specific vaccine information, please refer to:http://www.bccdc.ca/health-info/diseasesconditions/mpox#vaccination

Though the Mpox vaccine shows significant reduction in symptoms, most people have received only one dose of out of the recommended two dose series. Clinicians should encourage eligible patients to be vaccinated, and to encourage those who have received only one dose to complete their vaccine series with a second dose.

For more information about Mpox and booking vaccination appointments see: Mpox - Fraser Health Authority

Mumps Testing

Mumps is a viral infection caused by the mumps virus. It presents as fever and malaise with parotitis, and in some cases orchitis/oophoritis.

The reverse transcriptase polymerase chain reaction (RT-PCR) assay is the test of choice for the definitive diagnosis of an acute mumps infection. The preferred specimen for mumps diagnosis is a buccal swab collected within five days of symptom onset. If symptom onset was more than five days prior to specimen collection, urine PCR can be performed up to 14 days after the onset of prodromal symptoms. For oral specimens, use a BCPHMRL virus isolation swab (Starplex, S160V, blue top). For urine mumps PCR collection, use a sterile container. Place specimens on ice, and ship immediately to the BC Centre for Disease Control Public Health Microbiology and Reference Laboratory.

Serology alone is less preferred for diagnosis of mumps, especially since collection of both acute and convalescent serum specimens is recommended. It is also difficult to interpret in a previously immunized person.

We have received reports that mumps serology testing was occasionally done in community settings to assess immune status after vaccination. No known serologic threshold correlates with immunity to mumps, so mumps serology should not be used for assessment of immunity (with a few specific exceptions).

The Measles-Mumps-Rubella (MMR) vaccine is given free (publicly funded) as part of the routine immunization schedule. Older children and adults can receive the vaccine if they have not been immunized and have not had disease.

For more information about Mumps and where to get the vaccine, please see: Mumps - Fraser Health Authority