Date Published: February 10, 2019
Publisher: The American Society of Tropical Medicine and Hygiene
Author(s): Eduard Matkovic, Diep K. Hoang Johnson, J. Erin Staples, Maria C. Mora-Pinzon, Lina I. Elbadawi, Rebecca A. Osborn, David M. Warshauer, Mark V. Wegner, Jeffrey P. Davis.
Jamestown Canyon virus (JCV), a mosquito-borne Orthobunyavirus (within the California serogroup), can cause severe neuroinvasive disease. According to national data during 2000–2013, 42% of the 31 documented JCV disease cases in the United States were detected in residents from Wisconsin. The Wisconsin Division of Public Health enhanced JCV surveillance by implementing routine use of JCV-specific immunoglobulin M (IgM) antibody testing followed by confirmatory JCV-specific plaque reduction neutralization testing on all patients with suspected cases of arboviral infection who had tests positive for arboviral immunoglobin at commercial laboratories. During 2011–2016, of the 287 Wisconsin specimens tested on the Arbovirus IgM Antibody Panel, 30 JCV cases were identified (26 confirmed and four probable). Twenty-seven (90%) JCV cases were detected after 2013. Among all cases, 17 (56%) were male and the median age was 54 years (range: 10–84 years). Fifteen patients had neuroinvasive disease, including meningitis (n = 9) and meningoencephalitis (n = 6). Although historically considered rare, the relatively high rate (0.12 cases/100,000 population) of diagnosis of JCV infections among Wisconsin residents during 2013–2016 compared with that in previous years suggests occurrence is widespread throughout Wisconsin and historically may have been under-recognized. This study aims to raise awareness of JCV infection for differential diagnosis among the arboviral diseases. Improved and timely diagnosis of arboviral disease is important in that it will provide more information regarding emerging infections and promote preventive measures to avoid mosquito-borne exposure and infection among residents of and visitors to affected areas.
Jamestown Canyon virus (JCV) is a mosquito-borne Orthobunyavirus within the California serogroup initially isolated during 1961 from a pool of Culiseta inornata mosquitoes from Jamestown Canyon, Colorado.1 Jamestown Canyon virus is widely distributed throughout temperate North America and has been isolated in at least 26 species of mosquitos; Aedes and Ochlerotatus species are the primary vectors in the Midwestern United States.2–8 Viral transmission occurs through the bite of an infected mosquito.
During 2011–2016, 30 cases of JCV disease (26 confirmed and four probable) were identified in Wisconsin residents (Figure 1). Before implementation of enhanced surveillance efforts during 2013, only three cases of JCV disease had ever been detected by the WDPH. During 2013–2016, 27 cases were detected, including 12 during 2013, five during 2014, four during 2015, and six during 2016. The mean annual reported incidence of JCV disease in Wisconsin increased about 4.5-fold from 0.03 cases/100,000 population during 2011–2012 to 0.12 cases/100,000 population during 2013–2016.
Enhanced surveillance efforts, including testing for JCV infections among persons with evidence of arboviral IgG or IgM antibody and compatible clinical signs and symptoms to an arboviral infection, has substantially increased the number of JCV cases detected in Wisconsin. During 2011–2016, the 30 cases of JCV disease reported among Wisconsin residents represent more than half of all cases of JCV disease reported in the United States during that interval.2,23 Although it is unclear whether the small number of cases reported during 2011–2012, the initial 2 years of Wisconsin’s JCV surveillance, was related to limited JCV transmission, results of the current enhanced surveillance suggest that human JCV infection occurs more frequently than previously thought.
Although historically considered rare, the relatively high rate of diagnosis of JCV disease among Wisconsin residents compared with rates noted elsewhere in the United States suggests the JCV disease occurrence is widespread throughout Wisconsin and affects a wide range of age groups. The increase in detection of JCV infection and disease in Wisconsin was more likely the result of enhanced surveillance that incorporated sensitive diagnostic methods and complete reporting, rather than the emergence of JCV. Jamestown Canyon virus infections have been likely underreported, which might result from lack of commercially available JCV-related testing, misdiagnosis resulting from cross-reactivity with other arboviruses, and lack of awareness among medical providers and other health professionals. Our enhanced surveillance efforts likely improved diagnosis of JCV disease, increased JCV disease recognition, and decreased rates of false-positive IgM results for related viruses such as LACV in Wisconsin. Through enhanced efforts, surveillance in Wisconsin was better able to quantify the burden and public health impact of JCV disease.