Test Code: 906
Panel Components:

• 403 MVista® Histoplasma DNA, PCR
• 404 MVista® Blastomyces DNA, PCR
• 405 MVista® Coccidioides DNA, PCR
• 406 MVista® Pneumocystis canis DNA, PCR

Accepted Specimen Types:

• Bronchoalveolar lavage (BAL) fluid, transtracheal wash fluid, orotracheal wash fluid, cavitary effusion

Clinical Significance:
Histoplasma spp. is a dimorphic fungus which is the causative agent of histoplasmosis, which can cause disease localized to the lung and associated lymph nodes or disseminate to any organ in the body. Multisystemic disease is common. Histoplasmosis is endemic to parts of the Americas, Asia, and Africa, but can occur elsewhere. The most accurate non-invasive biomarker test is Histoplasma antigen detection in urine and PCR should be done in conjunction with antigen testing. This polymerase chain reaction assay can provide rapid and specific detection and differentiation of Histoplasma spp. directly from clinical specimens. A negative PCR result does not rule out histoplasmosis.

Blastomyces dermatitidis and B. gilchristii are dimorphic fungi which are the causative agents of blastomycosis, which can cause disease localized to the lung and associated lymph nodes, or disseminate to any organ in the body. Multisystemic disease is common. Blastomycosis is endemic to parts of the United States, Canada, Africa, the Middle East, and India, but can occur elsewhere. The most accurate non-invasive biomarker test is Blastomyces antigen detection in urine, and PCR should be done in conjunction with antigen testing. This polymerase chain reaction assay can provide rapid and specific detection and differentiation of Blastomyces dermatitidis and Blastomyces gilchristii directly from clinical specimens. A negative PCR result does not rule out blastomycosis.

Coccidioides immitis and Coccidioides posadasii are dimorphic fungi which are the causative agents of coccidioidomycosis (Valley Fever), which often causes disease in the lung and associated lymph nodes. Dissemination to other body systems also occurs. Coccidioidomycosis is endemic to the western United States, as well as Mexico and Central America. The gold standard for diagnosis of coccidioidomycosis is enzyme immunoassay (EIA) antibody used in conjunction with an immunodiffusion (ID). PCR should be used in conjunction with antibody testing. This polymerase chain reaction assay can provide rapid and specific detection and differentiation of Coccidioides immitis and C. posadasii directly from clinical specimens. A negative PCR result does not rule out coccidioidomycosis.

Pneumocystis canis is an opportunistic fungal pathogen causing pneumonia in dogs. Interpretation of PCR results should be done in combination with other clinical findings, including clinical signs, physical examination, and thoracic imaging. A positive result demonstrates that P. canis DNA is present in the sample and could be the cause of disease. A negative result does not rule out P. canis as the cause of disease.

Multiplex PCR allows for the simultaneous detection of multiple fungal pathogens from a single sample. This is especially valuable in animals presenting with non-specific respiratory symptoms, where fungal infections can mimic bacterial or viral infections. These fungi (Histoplasma, Blastomyces, Coccidioides, and Pneumocystis) are common causes of opportunistic infections. Early and accurate identification can significantly improve outcomes. In addition, animals might have co-infections with more than one fungal pathogen and multiplex PCR can identify these cases, allowing for more comprehensive treatment planning.

Methodology: Qualitative Real-Time PCR (Polymerase Chain Reaction)
Specimen Collection: Transfer 2 mL of bronchoalveolar lavage (BAL) fluid to a sterile, leakproof container. Tracheal aspirate and bronchial wash will be reported with a rare specimen comment.
Minimum Specimen Requirements: 0.5mL bronchoalveolar lavage (BAL) fluid
Specimen Stability:

• Room Temperature/Ambient: 21 days
• Refrigerated: 21 days
• Frozen: 30 days

Specimen Rejection:

• Sputum, blood, serum, plasma, tissue, feces, urine, or swab samples.
• Specimens with particulate matter or viscosity that would not allow the specimen to be pipetted will be rejected.

Turnaround Time: 24-48 hours, Monday through Friday
Reference Range: Not detected
Interpretative Information:PCR testing should be done in conjunction with appropriate antigen or antibody testing. A POSTIVE PCR result indicates the DNA was detected in the sample and that organism could be the cause of disease. Some organisms (molds and yeasts) can be commensals (or colonizers) and found in non-sterile locations such as the respiratory, GI, and urinary systems – without causing disease. A NEGATIVE result indicates DNA was not detected in the sample but does not rule-out that organism as the cause of disease. All results should be interpreted considering the full clinical picture.