Key points
- Serologic testing is the primary method for diagnosing Jamestown Canyon virus disease.
- A positive Jamestown Canyon virus-specific immunoglobulin (Ig) M test result should be confirmed by neutralizing antibody testing at a state public health laboratory or ÐÇ¿ÕÓéÀÖ¹ÙÍø.
- Contact your state or local health department for assistance with diagnostic testing.
Considerations
Serologic testing remains the primary method for diagnosing Jamestown Canyon virus disease. However, several studies have found a high prevalence of seropositivity for Jamestown Canyon virus in humans, suggesting a high proportion of asymptomatic infections. In addition, it is not known how long IgM antibodies can be detected in serum following a Jamestown Canyon virus infection; therefore, a positive IgM antibody test may reflect past infection. This can make interpreting serologic testing difficult when diagnosing a patient with acute disease.
For immunocompromised patients, molecular testing (e.g., RT-PCR) might be more sensitive than serologic testing.
Jamestown Canyon virus disease is a nationally notifiable condition. All cases should be reported to local public health authorities in a timely manner. Reporting can assist local, state, and national authorities to recognize outbreaks and to implement control measures to reduce further infections.
Recommended tests
Combined with a consistent clinical presentation, a preliminary diagnosis of Jamestown Canyon virus disease can be made by detection of Jamestown Canyon virus-specific IgM antibodies in serum or cerebrospinal fluid (CSF).
- Jamestown Canyon virus-specific IgM testing can be done at some state public health laboratories and at ÐÇ¿ÕÓéÀÖ¹ÙÍø.
- Commercial IgM testing for California serogroup viruses is available and can be used for initial testing.
- A positive Jamestown Canyon virus or California serogroup virus IgM test result should be confirmed by neutralizing antibody testing at a state public health laboratory or ÐÇ¿ÕÓéÀÖ¹ÙÍø.
- Because of the high prevalence of Jamestown Canyon virus antibodies in asymptomatic persons, diagnosis of a recent Jamestown Canyon virus infection is most accurately made by testing acute and convalescent sera to assess for at least a 4-fold rise in neutralizing antibody titers. If a convalescent cannot be obtained, use epidemiological and clinicial information to determine the likelihood of an acute infection.
- Some patients who are severely immunocompromised might require molecular (e.g., RT-PCR) testing for diagnosis.
To submit specimens for testing, please contact your state or local health department. They can assist you with determining if samples should be sent to the ÐÇ¿ÕÓéÀÖ¹ÙÍø Arbovirus Diagnostic Laboratory for further testing. Specimens should be submitted to ÐÇ¿ÕÓéÀÖ¹ÙÍø through state health departments. All results will be sent from ÐÇ¿ÕÓéÀÖ¹ÙÍø to the appropriate state health department.
Diagnostic Algorithm
