Nonpolio Enterovirus and Human Parechovirus Surveillance — United States, 2006–2008

GR Villarruel, MPH; GE Langley, MD; MS Oberste, PhD; M Pallansch, PhD


Morbidity and Mortality Weekly Report. 2010;59(48):1577-1580. 

In This Article

Editorial Note

The findings in this report are consistent with previous trends regarding the most commonly detected enterovirus serotypes.[4] During 2006–2008, CVB1 became the predominant enterovirus serotype identified, found in several states, and concentrated in a few. Common clinical presentations of CVB1 include aseptic meningitis, myocarditis, pleurodynia, and hand, foot, and mouth disease. CVB1 generally shows an epidemic pattern of circulation with irregular intervals of increased circulation usually lasting 2–3 years.[4] During 1970–2005, CVB1 accounted for approximately 2% of reports with known serotype, with an increase of CVB1 observed in the early 1990s and then again in the early 2000s.[4] In 2007, increased detections of CVB1 reported to NESS led to an investigation that identified severe neonatal disease and deaths associated with CVB1 infection in multiple states.[2,5]

Since 1997, EV71 has caused widespread outbreaks of hand, foot, and mouth disease in several Asian countries.[3] A small proportion of cases have resulted in encephalitis and death. In the United States, small clusters of serious disease were detected during 2003–2005.[6] Although there was an increase in reported EV71 detections in the United States during 2006–2008, EV71 detections were uncommon.

HPeV1 usually has been associated with mild gastrointestinal and respiratory symptoms, meningitis, and neonatal sepsis.[7] HPeV1 was one of the 15 most common detections during 2006–2008; no other HPeV types were reported during that period. HPeV cannot be detected by EV-specific assays. CDC's Picornavirus Laboratory has performed the majority of HPeV typing reported to NESS but has worked with clinical and state laboratories to enhance their HPeV diagnostic and molecular typing assays[8] to improve detections and enhance parechovirus surveillance.

The findings in this report are subject to at least four limitations. First, enteroviral infections other than poliovirus infections are not nationally notifiable in the United States. NESS is a passive system that relies on voluntary participation from laboratories, so findings are not necessarily representative of national or regional enterovirus activity. Although there might be more reports emanating from one state or region, it might not represent an increased burden of disease in that state or region. Second, the findings are limited by the lack of clinical information; however, most detections likely represent serious disease because cerebral spinal fluid was the most common source of detection. Third, most testing is performed during the summer months; circulation during other parts of the year might go undetected. Finally, although monthly NESS reporting is encouraged, not all participating laboratories submit timely data, which can delay accurate reporting.

NESS could be improved with more regular reporting by current laboratories and by increasing the number of participating laboratories. NREVSS provides enterovirus activity over a wider geographic area because more laboratories participate in the system, but it does not provide serotype or demographic information. The combined systems provide the best available data on enterovirus circulation in the United States.

Since July 2009, a simplified, Internet-based NESS system has allowed participating laboratories to easily input enterovirus detection data and to analyze national and state-based trends in enterovirus surveillance, by serotype. Additional information about this system is available by e-mail (


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as: