Background Subacute sclerosing panencephalitis (SSPE) is a fatal complication of measles. We reviewed California cases from 1998-2015 to understand risk factors for SPPE and estimate incidence. Methods SSPE cases had clinically compatible symptoms and measles antibody detection in cerebrospinal fluid (CSF) or medical record documentation of SSPE. Cases were identified though a state death certificate search, Centers for Disease Control and Prevention reports, or investigations for undiagnosed neurologic disease. Measles detection in CSF was performed by serology at the California Department of Public Health or at clinical laboratories. Results Seventeen SSPE cases were identified. Males outnumbered females 2.4:1. Twelve (71%) cases had a history of measles-like illness; all 12 had illness prior to 15 months of age. Eight (67%) children were exposed to measles in California. SSPE was diagnosed at a median age of 12 years (3-35 years), with a latency period of 9.5 years (2.5-34 years). Among measles cases reported to CDPH during 1988-1991, the incidence of SSPE was 1:1367 for children <5 years, and 1:609 for children <12 months at time of measles disease. Conclusions SSPE cases in California occurred at a high rate among unvaccinated children, particularly those infected during infancy. Protection of unvaccinated infants requires avoidance of travel to endemic areas, or early vaccination prior to travel at age 6-11 months. Clinicians should be aware of SSPE in patients with compatible symptoms, even in older patients with no specific history of measles infection. SSPE demonstrates the high human cost of "natural" measles immunity.

Background.Subacute sclerosing panencephalitis (SSPE) is a fatal complication of measles.Thought to be rare, SSPE incidence decreased with routine measles vaccination, but infants with measles remain at highest risk of this complication.We reviewed SSPE cases in California from 1998 to 2016 to understand current risk factors for SPPE.Methods.SSPE cases had a clinically compatible illness and either 1) measles IgG antibody detection in the cerebrospinal fluid; 2) characteristic pattern on electroencephalography; 3) typical histologic findings in brain biopsy; or 4) medical record documentation of SSPE-related complications.Cases were identified though a state death certificate search, reports from the Centers for Disease Control and Prevention, or through investigations for undiagnosed neurologic disease.Measles IgG detection was performed using indirect enzyme immunoassay at the California Department of Public Health (CDPH) or by immunofluorescence assay at clinical laboratories.Results.Seventeen SSPE cases were identified.Males outnumbered females 2.4:1.Twelve (71%) cases had a clinical history of a febrile rash illness compatible with measles; all 12 had illness prior to 15 months of age and measles vaccination.Eight (67%) children were living in the United States when they had measles.SSPE was diagnosed at a median age of 12 years (range 3-35 years), with a latency period of 9.5 years (range 2.5-34 years).Many cases had long-standing cognitive or motor problems prior to diagnosis.Among measles cases reported to CDPH during 1988-1991, incidence of SSPE was 1:1367 for children <5 years, and 1:609 for children <12 months at time of measles disease.Conclusion.SSPE cases in California occurred at much higher rate than previously published among unvaccinated children who were infected with measles in infancy.Protection of infants younger than 12-15 months of age, when measles vaccine is routinely administered, requires avoidance of travel to endemic areas, or early vaccination prior to travel.Clinicians should be aware of the possibility of SSPE in patients with compatible symptoms, even in older patients with no specific history of measles infection.SSPE demonstrates the high human cost of "natural" measles immunity.Disclosures.

BACKGROUND. Encephalitis is a complex, debilitating, and sometimes fatal neurologic condition to which children are especially prone. Mycoplasma pneumoniae, a common respiratory pathogen, has been implicated as an etiology of encephalitis. Evidence for recent or acute M pneumoniae infection has been demonstrated in limited studies of both pediatric and adult patients with encephalitis. PATIENTS AND METHODS. Unexplained encephalitis cases are referred to the California Encephalitis Project for diagnostic testing. Serum, cerebrospinal fluid, and respiratory specimens are tested by polymerase chain reaction and serology methods for the presence of multiple pathogens, including M pneumoniae. M pneumonia–associated cases of encephalitis were compared with other bacterial agents, herpes simplex virus 1, and enterovirus. RESULTS. Of 1988 patients referred to the California Encephalitis Project, evidence of acute M pneumoniae infection was found in 111 patients, of which 84 (76%) were pediatric patients. Eighty percent of the 84 patients were positive for M pneumoniae by serology alone. Cerebrospinal fluid polymerase chain reaction for M pneumoniae was rarely positive (2%). Patients with M pneumoniae–associated pediatric encephalitis were a median of 11 years old, progressed rapidly (median: 2 days from onset to hospitalization), and were often in the ICU (55%). Symptoms included fever (70%), lethargy (68%), and altered consciousness (58%). Gastrointestinal (45%) and respiratory (44%) symptoms were less common. Compared with patients with other bacterial as well as viral agents, patients with M pneumoniae–associated encephalitis had fewer seizures and less-severe hospital courses. CONCLUSIONS. M pneumoniae is the most common agent implicated in the California Encephalitis Project. Patients with M pneumoniae–associated encephalitis are predominantly pediatric, and their presentations are clinically similar to enterovirus encephalitis, although they frequently require intensive care with prolonged hospitalizations. Given that M pneumoniae infection is found more than any other pathogen, increased emphasis should be placed on elucidating the role and mechanism of M pneumoniae in encephalitis.

An outbreak of myocarditis occurred among adults in Illinois in 2003. Diagnostic testing of myocardial tissues from 3 patients and comprehensive tests for enterovirus and adenovirus of other specimens from patients were inconclusive. Appropriate specimen collection from patients with idiopathic cardiomyopathy and further enhancement of diagnostic techniques are needed.