Enterovirus

Test code: S0058 - Ultrasensitive qualitative detection of enterovirus by reverse transcription coupled real time polymerase chain reaction

The enteroviruses (EVs) are among the most common and most important viral pathogens of humans, and EVs also infect nonhuman primates. The EVs comprise 67 distinct serotypes within the family Picornaviridae. Most EV infections are asymptomatic. For symptomatic patients, the most common manifestation of EV infection may only be a nonspecific febrile illness with or without a rash. This so-called viral syndrome is one of the most common causes of fever among human children. Infected patients often develop upper respiratory symptoms very similar to illness caused by rhinoviruses in the winter months, making diagnosis very difficult.

Enteroviruses are the most common cause of meningitis in humans in the United States. It is also likely that EV infection in primates is a major cause of aseptic meningitis. Diagnosis of EV meningitis can be difficult, especially in young infant primates, because meningitis due to bacterial and other viral infection can present very similar symptoms. Even though EV meningitis is often benign in outcome and no specific therapy is indicated, EV-infected animals may be given unnecessary antibiotic and antiviral therapies due to misdiagnosis.

Laboratory diagnosis of enteroviruses is traditionally performed by viral culture and recognition of cytopathic effects, requiring a high degree of expertise and labor. Some EV serotypes, particularly within the coxsackievirus A group, do not grow at all in cell culture. Of greater concern is that 25 to 35% of specimens from human patients with characteristic EV infections are negative by cell culture (Chonmaitree et al., 1988) because of antibody neutralization in situ. Even though some EVs may grow in cell culture, they often grow very slowly, sometimes taking a week or more before any cytopathic effect can be observed.

Serological testing of EVs is not practical because there is no commonly shared antigen among the different EV serotypes (Herrmann et al., 1979). Detection of EVs using a molecular approach provides the best opportunity for rapid diagnosis of EVs in primates, because consensus sequences among different serotypes of EVs are available in the untranslated regions of EVs. Enterovirus detection by PCR over these consensus sequences thus provides the most rapid, sensitive and specific method for the diagnosis of this infection. The technique also helps eliminate false negative diagnoses.

Utilities:

• Help confirm the disease causing agent
• Help ensure that animal groups and populations are free of Enteroviruses
• Early prevention of spread of the virus among a group or population
• Minimize human exposure to the virus

References:
Chonmaitree, T., Ford, C., Sanders, C. and Lucia, H.L. (1988) Comparison of cell culture for rapid isolation of enteroviruses. J. Clin. Microbiol. 26:2576-2580.
Herrmann, J.E., Hendry, R.M. and Collins, F. (1979) Factors involved in enzyme-linked immunoassay of viruses and evaluation of the method for identification of enteroviruses. J. Clin. Microbiol. 10: 210-217.

Specimen requirements: 0.2 ml whole blood in EDTA (purple top) tube, or 0.2 ml CSF, urine, plasma, serum or nasal wash, or rectal swab, or throat swab, or 0.2 ml fresh or frozen 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 reverse transcription coupled real time PCR

Normal range: Nondetected