California Serogroup Research Articles

First Complete Genome Sequences of Two Keystone Viruses from Florida.

We report here the first complete sequences of two Keystone virus (KEYV) genomes isolated from Florida in 2005, which include the first two publicly available complete large (L) gene sequences. The sequences of the KEYV L segments show 75.99 to 83.86% nucleotide similarity with those of other viruses in the California (CAL) serogroup of bunyaviruses.

La Crosse Encephalitis Virus Infection in Field-Collected Aedes albopictus, Aedes japonicus, and Aedes triseriatus in Tennessee.

La Crosse virus (LACV) is a mosquito-borne virus and a major cause of pediatric encephalitis in the USA. La Crosse virus emerged in Tennessee and other states in the Appalachian region in 1997. We investigated LACV infection rates and seasonal abundances of the native mosquito vector, Aedes triseriatus, and 2 recently introduced mosquito species, Ae. albopictus and Ae. japonicus, in an emerging disease focus in Tennessee. Mosquitoes were collected using multiple trapping methods specific for Aedes mosquitoes at recent human case sites. Mosquito pools were tested via reverse transcriptase-polymerase chain reaction (RT-PCR) of the S segment to detect multiple Bunyamwera and California serogroup viruses, including LACV, as well as real-time RT-PCR of the M segment. A total of 54 mosquito pools were positive, including wild-caught adult females and laboratory-reared adults, demonstrating transovarial transmission in all 3 species. Maximum likelihood estimates (per 1,000 mosquitoes) were 2.72 for Ae. triseriatus, 3.01 for Ae. albopictus, and 0.63 for Ae. japonicus. We conclude that Ae. triseriatus and Ae. albopictus are important LACV vectors and that Ae. japonicus also may be involved in virus maintenance and transmission.

Severe La Crosse meningoencephalitis in children: report of two cases

La Crosse virus is an arbovirus of the California Serogroup (Family Bunyaviridae), transmitted by the “tree-hole mosquito,” Aedes triseriatus . La Crosse encephalitis cases occur annually from July to October. The majority of cases are asymptomatic, only a minority (

Emerging mosquito-borne bunyaviruses in Canada.

California serogroup and Cache Valley viruses are arboviruses (tick- and mosquito-borne pathogens) belonging to the genus Orthobunyavirus (Family Bunyaviridae). Although the majority of exposures to these viruses result in asymptomatic or mild infections, both California serogroup and Cache Valley viruses can cause febrile and neurological diseases similar in nature to those associated with infections by West Nile virus. California serogroup and Cache Valley viruses are widely distributed across North America and circulate in a number of vertebrate hosts and mosquito vectors, including several species of Aedes and other non-Culex mosquitoes. The Jamestown Canyon and snowshoe hare viruses are the most common kind of California serogroup viruses found in Canada and have been identified throughout the country. These potential pathogens may be contributing to a higher burden of illness than previously recognized and should be considered as part of the differential diagnosis for febrile and neuroinvasive disease during the mosquito season. Diagnosis can be made by requesting a diagnostic panel at the Viral Zoonoses program at the National Microbiology Laboratory. To decrease the risk of infection, education about these viruses and the importance of personal preventive measures is warranted.

Jamestown Canyon Virus Disease in the United States-2000-2013.

Jamestown Canyon virus (JCV) is a mosquito-borne orthobunyavirus in the California serogroup that can cause an acute febrile illness, meningitis, or meningoencephalitis. We describe epidemiologic and clinical features for JCV disease cases occurring in the United States during 2000-2013. A case of JCV disease was defined as an acute illness in a person with laboratory evidence of a recent JCV infection. During 2000-2013, we identified 31 cases of JCV disease in residents of 13 states. The median age was 48 years (range, 10-69) and 21 (68%) were male. Eleven (35%) case patients had meningoencephalitis, 6 (19%) meningitis, 7 (23%) fever without neurologic involvement, and 7 (23%) had an unknown clinical syndrome. Fifteen (48%) were hospitalized and there were no deaths. Health-care providers and public health officials should consider JCV disease in the differential diagnoses of viral meningitis and encephalitis, obtain appropriate specimens for testing, and report cases to public health authorities.

Investigations on California Serogroup Orthobunyaviruses in the Tyrols: First Description of Tahyna Virus in The Alps

Seroprevalence rates for immunoglobulin G (IgG) antibodies to Tahyna virus (TAHV) and Inkoo virus (INKV) were determined in sera of 1630 blood donors from North, East, and South Tyrol by immunofluorescence assays (IFAs) and confirmatory serum neutralization tests (SNTs). Ten sera (0.6%) reacted positive by TAHV IFA, five of which (0.3%) were confirmed by SNT. Eleven sera (0.7%) reacted positive in the INKV IFA; only one thereof (0.06%) was verified by subsequent SNT. To identify the source of infections, mosquitoes were trapped at 18 sampling sites in the study area, resulting in the collection of 2571 adult mosquitoes: 1254 individuals of the genus Aedes (48.8% of total) including A. albopictus, 640 Culex (24.9%), 303 Coquillettidia (11.8%), 252 Ochlerotatus (9.8%), 49 Anopheles (1.9%), and 73 mosquitoes of the genus Culiseta (2.8%). The mosquitoes were pooled according to species, trapping site, and time, and were tested by RT-PCR for the presence of California serogroup orthobunyavirus nucleic acids. PCR amplification products were obtained in five of 195 pools (2.6%), and all were identified as TAHVs by subsequent sequencing. This represents the first evidence of TAHV circulation and human exposure in the Tyrols and in the alpine region in general. Interestingly, all TAHV sequences were identified in Culex pipiens/torrentium mosquitoes. Whether other California serogroup orthobunyaviruses such as INKV are also circulating in this area is subject of further investigations on larger numbers of mosquitoes.

Zoonotic infections in communities of the James Bay Cree territory: An overview of seroprevalence.

The Cree communities of James Bay are at risk for contracting infectious diseases transmitted by wildlife. Data from serological testing for a range of zoonotic infections performed in the general population (six communities), or trappers and their spouses (one community), were abstracted from four population-based studies conducted in Cree territory (Quebec) between 2005 and 2009. Evidence of exposure to Trichinella species, Toxoplasma gondii, Toxocara canis, Echinococcus granulosus, Leptospira species, Coxiella burnetii and Francisella tularensis was verified in all communities, whereas antibodies against Sin Nombre virus and California serogroup viruses (Jamestown Canyon and snowshoe hare viruses) were evaluated in three and six communities, respectively. Seroprevalence varied widely among communities: snowshoe hare virus (1% to 42%), F tularensis (14% to 37%), Leptospira species (10% to 27%), Jamestown Canyon virus (9% to 24%), C burnetii (0% to 18%), T gondii (4% to 12%), T canis (0% to 10%), E granulosus (0% to 4%) and Trichinella species (0% to 1%). No subject had serological evidence of Sin Nombre virus exposure. These data suggest that large proportions of the Cree population have been exposed to at least one of the targeted zoonotic agents. The Cree population, particularly those most heavily exposed to fauna, as well as the medical staff living in these regions, should be aware of these diseases. Greater awareness would not only help to decrease exposures but would also increase the chance of appropriate diagnostic testing.

Zoonotic Infections Among Employees from Great Smoky Mountains and Rocky Mountain National Parks, 2008–2009

U.S. National Park Service employees may have prolonged exposure to wildlife and arthropods, placing them at increased risk of infection with endemic zoonoses. To evaluate possible zoonotic risks present at both Great Smoky Mountains (GRSM) and Rocky Mountain (ROMO) National Parks, we assessed park employees for baseline seroprevalence to specific zoonotic pathogens, followed by evaluation of incident infections over a 1-year study period. Park personnel showed evidence of prior infection with a variety of zoonotic agents, including California serogroup bunyaviruses (31.9%), Bartonella henselae (26.7%), spotted fever group rickettsiae (22.2%), Toxoplasma gondii (11.1%), Anaplasma phagocytophilum (8.1%), Brucella spp. (8.9%), flaviviruses (2.2%), and Bacillus anthracis (1.5%). Over a 1-year study period, we detected incident infections with leptospirosis (5.7%), B. henselae (5.7%), spotted fever group rickettsiae (1.5%), T. gondii (1.5%), B. anthracis (1.5%), and La Crosse virus (1.5%) in staff members at GRSM, and with spotted fever group rickettsiae (8.5%) and B. henselae (4.3%) in staff at ROMO. The risk of any incident infection was greater for employees who worked as resource managers (OR 7.4; 95% CI 1.4,37.5; p=0.02), and as law enforcement rangers/rescue crew (OR 6.5; 95% CI 1.1,36.5; p=0.03), relative to those who worked primarily in administration or management. The results of this study increase our understanding of the pathogens circulating within both parks, and can be used to inform the development of effective guidelines and interventions to increase visitor and staff awareness and help prevent exposure to zoonotic agents.

Roles of host species, geographic separation, and isolation in the seroprevalence of Jamestown Canyon and snowshoe hare viruses in Newfoundland.

California serogroup viruses, including Jamestown Canyon virus (JCV) and snowshoe hare virus (SSHV), are mosquito-borne members of the Bunyaviridae family and are endemic across North America. These arboviruses are potential pathogens which occasionally cause neuroinvasive disease in humans and livestock. A neutralization assay was used to document JCV and SSHV seroprevalence using blood collected from a variety of domestic and wildlife host species. These species were sampled in an island setting, Newfoundland, which contains diverse ecoregions, ecological landscapes, and habitats. Seroprevalence rates for each virus differed significantly among host species and within certain species across different geographic areas. JCV was significantly associated with large mammals, and SSHV was significantly associated with snowshoe hares. Seroprevalence rates in the 5 species of animals tested for prior exposure to JCV ranged from 0% in snowshoe hares to 64% in horses. Seroprevalence rates for SSHV ranged from less than 1% in bovines to 55% in all snowshoe hares. The seroprevalence of SSHV differed significantly (P < 0.05) among hares occupying the discrete habitats of watersheds separated by 14 to 35 km. Cattle on farms in boreal forest landscapes displayed significantly higher JCV seroprevalence (P < 0.001) than those on farms located in seacoast landscapes. Lifelong geographic isolation of cattle to insular Newfoundland was associated with significantly lower JCV seroprevalence (P < 0.01) than that for cattle which had lived off-island.

Jamestown Canyon Virus: A Potential Cause for Acute Inflammatory Polyneuropathy? (P03.256)

Objective: To describe the first case reports of human infections with Jamestown Canyon virus (JCV), an emerging viral pathogen, in Nova Scotia. Background JCV is a mosquito-borne zoonosis belonging to the California serogroup of bunyaviruses, endemic in North America. Although seroprevalence data suggests that up to 88% of deer along the south shore region of Nova Scotia (NS) have been infected by JCV, human infections have not been reported. Design/Methods: The clinical and demographic data of our cases were reviewed. Serologic testing for JCV infection was done at the National Microbiology Laboratory using plaque reduction neutralization (PRNT). PubMed search was performed to determine the typical clinical manifestations of JCV in humans. Results: Two human cases of probable JCV infection were identified in 2010 and 2011 in NS presenting as acute polyneuropathies with cognitive changes. CSF showed an inflammatory reaction with lymphocytic pleocytosis and elevated protein. Electromyography and nerve conduction studies demonstrated acute polyneuropathy in both, with prominent demyelination in one. Microbiologic investigations including culture, PCR for HSV, and enteroviruses were negative. Serology for typical arboviruses were negative. Serum IgM and PRNT for JCV was positive. Both cases were treated with intravenous immunoglobulin with improvement, but deficits from the polyneuropathy persisted. Literature review indicated that JCV infection is often limited to a mild febrile illness which can progress to an encephalitis and/or meningitis. No reports of demyelinating polyneuropathy as a result of JCV were previously identified. Conclusions: These are the first reported probable cases in humans in NS. The atypical nature of these presentations suggests that JCV may cause a greater spectrum of neurologic disease than previously described. Clinicians should consider JCV in their differential of patients presenting with inflammatory polyneuropathies in NS and other areas with high prevalence in their zoonotic reservoir. Disclosure: Dr. Rasool has nothing to disclose. Dr. Benstead has nothing to disclose. Dr. Drebot has nothing to disclose. Dr. Hatchette has nothing to disclose.

Seroprevalence of 10 zoonotic infections in 2 Canadian Cree communities

We evaluated the seroprevalence of 10 zoonotic agents among the general population (15 years old and over) of Eastmain and Wemindji, James Bay, Quebec, in 2007. Overall seroprevalence rates were similar between the 2 communities. Nearly half the individuals tested ( n = 251; 146 women, 105 men) were seropositive ( n = 115) for at least one zoonosis. The highest seroprevalence rates were for Leptospira sp. (23%), Francisella tularensis (17%), and the California serogroup viruses (JC and SSH viruses) (10%). The other zoonoses ( Toxoplasma gondii, Coxiella burnetii, Echinococcus granulosus, Toxocara canis, and Trichinella sp.) had seroprevalence rates ≤5%; no exposures were identified to hantaviruses (Sin Nombre virus). Overall, seropositivity was related to age, gender, hunting, and owning a dog. There was no medical history suggestive of overt diseases. Nonetheless, physicians should consider these agents when confronted with difficult or confusing diagnoses. In particular, the bacterial zoonoses should be ruled out in individuals with high or prolonged fever.

Interferon Antagonist NSs of La Crosse Virus Triggers a DNA Damage Response-like Degradation of Transcribing RNA Polymerase II

La Crosse encephalitis virus (LACV) is a mosquito-borne member of the negative-strand RNA virus family Bunyaviridae. We have previously shown that the virulence factor NSs of LACV is an efficient inhibitor of the antiviral type I interferon system. A recombinant virus unable to express NSs (rLACVdelNSs) strongly induced interferon transcription, whereas the corresponding wt virus (rLACV) suppressed it. Here, we show that interferon induction by rLACVdelNSs mainly occurs through the signaling pathway leading from the pattern recognition receptor RIG-I to the transcription factor IRF-3. NSs expressed by rLACV, however, acts downstream of IRF-3 by specifically blocking RNA polymerase II-dependent transcription. Further investigations revealed that NSs induces proteasomal degradation of the mammalian RNA polymerase II subunit RPB1. NSs thereby selectively targets RPB1 molecules of elongating RNA polymerase II complexes, the so-called IIo form. This phenotype has similarities to the cellular DNA damage response, and NSs was indeed found to transactivate the DNA damage response gene pak6. Moreover, NSs expressed by rLACV boosted serine 139 phosphorylation of histone H2A.X, one of the earliest cellular reactions to damaged DNA. However, other DNA damage response markers such as up-regulation and serine 15 phosphorylation of p53 or serine 1524 phosphorylation of BRCA1 were not triggered by LACV infection. Collectively, our data indicate that the strong suppression of interferon induction by LACV NSs is based on a shutdown of RNA polymerase II transcription and that NSs achieves this by exploiting parts of the cellular DNA damage response pathway to degrade IIo-borne RPB1 subunits.

Isolation of Jamestown Canyon and snowshoe hare viruses (California serogroup) from Aedes mosquitoes in western Massachusetts.

Three isolates of Jamestown Canyon virus and one isolate of snowshoe hare virus (California serogroup) were obtained from adult Aedes females collected in western Massachusetts in 1982. Jamestown Canyon virus was isolated from Aedes abserratus/punctor once, and from Aedes intrudens twice. Snowshoe hare virus was isolated from Aedes stimulans group mosquitoes. La Crosse encephalitis (LAC) virus was not isolated from 1,552 adult Aedes triseriatus, nor from 22,557 Aedes triseriatus larvae. However, sera from 1/178 eastern chipmunks, 5/31 gray squirrels, and 8/144 white-tailed deer had neutralizing antibody to LAC virus. No sentinel rabbits placed at sites yielding virus isolates seroconverted to CAL viruses in either year.

A duplex real-time reverse transcriptase polymerase chain reaction assay for the detection of California serogroup and Cache Valley viruses

A duplex TaqMan real-time reverse transcriptase polymerase chain reaction (PCR) assay was developed for the detection of California (CAL) serogroup viruses and Cache Valley virus (CVV), for use in human surveillance. The targets selected for the assay were the sequences encoding the nucleocapsid protein of CAL and the G1 glycoprotein of CVV. Conserved regions were selected by aligning genetic sequences from various strains available in the GenBank database. Primers and probes were selected in conserved regions. The assay sensitivity was 75 gene copies (gc)/reaction for CAL serogroup viruses and 30 gc/reaction for CVV. The performance of the assay was linear over at least 6 log 10 gc. The assay was specific, given that it did not cross-react with a variety of pathogens. It did, however, detect 11 viruses within the CAL serogroup and 12 CVV isolates. The use of an internal control ensured that possible inefficiency in nucleic acid extraction or PCR inhibition would be detected.

O53 An overview of California serogroup virus diagnostics & surveillance in Canada in 2008

Antibodies specific for Rift Valley fever virus (RVFV) can be detected by diverse methods, including ezyme-linked immunosortbent assay (ELISA) and virus neutralization test (VNT). The VNT is superior in sensitivity and specificity and is therefore considered the gold standard serological assay. Classical VNTs make use of virulent RVFV and therefore have to be performed in biosafety level 3 laboratories. Here, we report the development of a novel VNT that is based on an avirulent RVFV expressing the enhanced green fluorescent protein (eGFP), which can be performed safely outside level 3 biocontainment facilities. Evaluation with a broad panel of experimental sera and field sera demonstrated that this novel VNT is faster and more sensitive than the classical VNT.

Ecology of Arboviruses in Sri Lanka: A Summary of Studies from 1984-1990

Studies on arboviruses carried out between 1984 -1990 at the University of Peradeniya are summarized here. The isolation of Nairobi sheep disease virus, Getah, Batai and Arkonam and serological evidence of the circulation of California encephalitis serogroup and Chandipura viruses have been reported for the first time in Sri Lanka. The ecology of Japanese encephalitis (JE) in areas with epidemic disease and sylvatic infection has been compared. A synchronous pattern of seroconversion in pigs and seroprevalence in cattle are more predictive of epidemic JE risk than overall porcine seroprevalence which is a good indicator of the presence of sylvatic JE rather than of human epidemic risk. Relatively modest changes in vector abundance associated with rainfall or agricultural practices have dramatic changes on the emergence of epidemic JE. Chandipura virus which is known to cause major outbreaks of encephalitis in India is endemic in Sri Lanka as are viruses belonging to the California encephalitis serogroup. Both these viruses are potential causes of human encephalitis and should be sought in patients with undiagnosed encephalitis. Nairobi sheep disease virus is endemic in animals (especially goats) and infects humans working closely with such livestock. Arboviruses remain an under-recognised cause of human and animal disease and an inter-sectoral multidisciplinary approach is needed to confront such emerging infectious disease threat. Keywords: Japanese encephalitis, California serogroup, Alphavirus, mosquito, Chandipura virus doi: 10.4038/cjsbs.v37i1.492 Cey. J. Sci. (Bio. Sci.) 37 (1): 7-14, 2008

Viruses in the Anopheles A, Anopheles B, and Tete Serogroups in the Orthobunyavirus Genus (Family Bunyaviridae ) Do Not Encode an NSs Protein

Viruses in the genus Orthobunyavirus, family Bunyaviridae, have a genome comprising three segments (called L, M, and S) of negative-sense RNA. Serological studies have classified the >170 named virus isolates into 18 serogroups, with a few additional as yet ungrouped viruses. Until now, molecular studies and full-length S-segment nucleotide sequences were available for representatives of eight serogroups; in all cases, the S segment encodes two proteins, N (nucleocapsid) and NSs (nonstructural), in overlapping open reading frames (ORFs) that are translated from the same mRNA. The NSs proteins of Bunyamwera virus (BUNV) and California serogroup viruses have been shown to play a role in inhibiting host cell mRNA and protein synthesis, thereby preventing induction of interferon (IFN). We have determined full-length sequences of the S segments of representative viruses in the Anopheles A, Anopheles B, and Tete serogroups, and we report here that these viruses do not show evidence of having an NSs ORF. In addition, these viruses have rather longer N proteins than those in the other serogroups. Most of the naturally occurring viruses that lack the NSs protein behaved like a recombinant BUNV with the NSs gene deleted in that they failed to prevent induction of IFN-beta mRNA. However, Tacaiuma virus (TCMV) in the Anopheles A serogroup inhibited IFN induction in a manner similar to that of wild-type BUNV, suggesting that TCMV has evolved an alternative mechanism, not involving a typical NSs protein, to antagonize the host innate immune response.

An Overview of Arboviruses and Bunyaviruses

Arboviruses belong to various families of viruses that are transmitted by arthropods, mainly mosquitoes and ticks. Arboviruses that cause human encephalitis in the United States are members of 3 main virus families: Togaviridae, Flaviviridae, and Bunyaviridae; they include St. Louis encephalitis (SLE), Western equine encephalitis (WEE), Eastern equine encephalitis (EEE), La Crosse virus (LAC), and other California serogroup viruses. In the United States, the incidence is usually 150 to 3,000 cases per year. Most infections are asymptomatic or may result in a nonspecific flu-like syndrome, but if clinical cases do occur, the consequences may be serious. Diseases caused by arboviruses include encephalitis, febrile diseases, and hemorrhagic fevers. Rapid serologic assays such as IgM-capture ELISA (MAC-ELISA) and IgG ELISA can be used soon after infection for diagnosis. There is no spe- cific treatment and therapy is mainly support- ive. Prevention includes vector control, educat- ing the public to avoid high-risk areas, wearing protective clothing, and using DEET-containing insect repellents.

An Unusual Cause of Vertigo With Positive 14-3-3 Protein in Cerebrospinal Fluid

California serogroup viral infections are the most common reported etiology of arboviral encephalitis in the United States. Since 2002, only 29 cases have been reported in Michigan, mostly in children. We report a case of a 27-year-old woman presenting with vertigo and whose cerebrospinal fluid contained 14-3-3 protein.

Epidemiology of Neuroinvasive Arboviral Disease in the United States, 1999–2007

From 1999-2007, the most common causes of neuroinvasive arboviral disease in the United States, after West Nile virus (WNV), were California (CAL) serogroup viruses, St. Louis encephalitis virus (SLEV), and eastern equine encephalitis virus (EEEV). The CAL serogroup virus disease was primarily reported from Appalachia and the upper Midwest, SLEV disease from southern states, and EEEV disease from areas along the Atlantic and Gulf coasts. Children accounted for 88% of CAL serogroup virus disease, whereas 75% of SLEV disease occurred among older adults. The EEEV disease had the highest case-fatality rate (42%). The incidence of CAL serogroup virus and EEEV disease remained stable before and after the detection of WNV in the United States in 1999. The SLEV disease declined 3-fold after 1999; however, SLEV disease has occurred in sporadic epidemics that make trends difficult to interpret. The CAL serogroup virus, SLEV, and EEEV disease are persistent public health concerns in the United States warranting ongoing prevention efforts.