environmental/diagnostic assay data sheet

Coccidioides (Valley Fever) PCR test

Test code: F0011 - Ultrasensitive detection of Coccidioides immitis / Coccidioides posadasii by real time PCR.

Coccidioides species are dimorphic fungi. Coccidioides immitis is endemic to the San Joaquin valley of California; Coccidioides posadasii is found in desert regions of the southwestern United States including Arizona, Utah, New Mexico, and West Texas, and also in parts of Mexico, Argentina, Paraguay and Central America. There is very little difference in morphology or clinical presentation between the 2 species, and both can cause the disease coccidioidomycosis, also referred to as "Valley Fever."

Coccidioides fungi are commonly found in soil and dust in endemic areas (Johnson et al., 2014). Arthroconidida are the infectious form of the fungi. When the arthroconidida dissociate, they can be carried by the wind for many miles. Coccidioidomycosis cases increase when there are rainy summers followed by dry winters, and after earthquakes or after humans disturb the soil by plowing, construction or similar activities.

When the anrthroconidida are inhaled into the lungs, they transform into multinucleated spherical structures containing hundreds of endospores. Most people will only develop a mild or asymptomatic pulmonary infection which resolves without intervention. However, some people who are infected may develop an apparent community-acquired pneumonia which often has an associated rash and arthralgias. The incubation time for the infection is about 2 weeks after exposure. Often these pneumonias resolve and only a few will progress to chronic pulmonary disease which can present as nodular or cavitary disease. Even fewer cases will progress to systemic or central nervous system coccidioidomycosis, but these forms are quite serious and are associated with heightened morbidity and mortality.

While most healthy individuals will normally not develop significant symptoms after exposure to these fungi, some groups of individuals are at increased risk for progression to extrapulmonary or disseminated coccidioidomycosis. These individuals are persons of African American or Filipino descent, pregnant women (especially those in their 3rd trimester) and patients with immunosuppressive conditions such as malignancies, transplant patients, and those with HIV or diabetes.

Molecular detection by polymerase chain reaction (PCR) is often the method of choice for detection and identification of Coccidioides species, not only because of its speed, sensitivity and specificity, but also because of its utility on a variety of specimen types (Gago et al., 2014). PCR can be used to detect these fungi in environmental samples such as dust, water or soil, as well as in various samples of biological origin.

Test results are presented in a concise, signed, easy-to-read PDF report optimized for documentation and recordkeeping.

Utilities:

• Detect these fungi in surface dust, soil, water or other environmental sample types
• Help confirm the presence of the disease causing agent in biological samples
• Minimize occupational exposure to these fungi
• Shorten the time required to confirm a clinical diagnosis of the infection
• Selection of appropriate treatment regimens

References:
Gago, S., Buitrago, M.J., Clemons, K.V., Cuenca-Estrella, M., Mirels, L.F. and Stevens, D.A. (2014) Development and validation of a quantitative real-time PCR assay for the early diagnosis of coccidioidomycosis. Diagn. Microbiol. Infect. Dis. 79:214-221.

Johnson, S.M., Carlson, E.L., Fisher, F.S. and Pappagianis, D. (2014) Demonstration of Coccidioides immitis and Coccidioides posadasii DNA in soil samples collected from Dinosaur National Monument, Utah. Med. Mycol. 52:610-617.

Specimen requirements: Surface dust swab or gauze pad, or 10 ml soil, or 10 ml water, or 0.2 ml cerebrospinal fluid, or 0.2 ml whole blood in EDTA (purple top tube), or 0.2 ml fresh, frozen or fixed tissue

Contact Zoologix if advice is needed to determine an appropriate specimen type for a specific diagnostic application. For specimen types not listed here, please contact Zoologix to confirm specimen acceptability and shipping instructions.

For all specimen types, if there will be a delay in shipping, or during very warm weather, refrigerate specimens until shipped and ship with a cold pack unless more stringent shipping requirements are specified. Frozen specimens should be shipped so as to remain frozen in transit. See shipping instructions for more information.

Turnaround time: 2 business days

Methodology: Qualitative real time polymerase chain reaction

Normal range: Nondetected