Background seropositivity to Jamestown Canyon virus can lead to diagnostic confusion.

Background seropositivity rates for specific antibodies to Jamestown Canyon Virus (JCV) can exceed 25 % in certain geographic areas in the United States. This can potentially lead to diagnostic confusion, as apparently illustrated by a patient from New Jersey with Powassan virus encephalitis, who also tested positive for antibodies to JCV.

La Crosse Virus Neuroinvasive Disease in Children: A Contemporary Analysis of Clinical/Neurobehavioral Outcomes and Predictors of Disease Severity.

BACKGROUND: La Crosse virus (LACV) is the most common neuroinvasive arboviral infection in children in the United States. However, data regarding predictors of disease severity and neurologic outcome are limited. Additionally, long-term neurologic and neurobehavioral outcomes remain relatively sparse. METHODS: This was a single-center, retrospective cohort study, followed by recruitment for a cross-sectional analysis of long-term neurobehavioral outcomes, among children aged 0-18 years with proven or probable LACV neuroinvasive disease (LACV-ND) between January 2009 and December 2018. Case ascertainment was assured by International Classification of Diseases, Ninth and Tenth Revision, Clinical Modification codes cross-referenced with laboratory results detecting LACV. Demographics, diagnostics, radiographs, and outcomes were evaluated. Recruitment of patients with prior diagnosis of LACV-ND occurred from January 2020 to March 2020, with assessment performed by validated pediatric questionnaires. RESULTS: One-hundred fifty-two children (83 males; median age, 8 years [interquartile range, 5-11.5 years]) were diagnosed with proven (n = 61 [47%]) and probable (n = 91 [60%]) LACV-ND. Sixty-five patients (43%) had severe disease. Altered mental status (AMS) (odds ratio [OR], 6.36 [95% confidence interval {CI}, 2.03-19.95]; P = .0002) and seizures at presentation (OR, 10.31 [95% CI, 3.45-30.86]; P = .0001) were independent predictors of severe disease. Epileptiform discharges on electroencephalogram (EEG) were independently associated with epilepsy diagnosis at follow-up (OR, 13.45 [95% CI, 1.4-128.77]; P = .024). Fifty-four patients were recruited for long-term neurobehavioral follow-up, with frequent abnormal assessments identified (19%-54%) irrespective of disease severity. CONCLUSIONS: Severe disease was observed frequently among children with LACV-ND. Seizures and AMS at presentation were independent predictors of severe disease. EEG may help determine long-term epilepsy risk. Long-term neurobehavioral issues are frequent and likely underrecognized among children with LACV-ND.

Double Crossed: A Case of La Crosse Encephalitis.

CASE REPORT: A 10-year-old male with T1DM and recent travel to North Carolina presented to an ED with 1 day of fever, vomiting, and headaches. He was discharged home with the presumptive diagnosis of viral gastroenteritis but returned nine hours later, agitated, and unable to speak. CSF showed pleocytosis. MRI brain was normal, and EEG showed intermittent seizures. He was started on antiepileptics. Antibiotics were discontinued after negative bacterial work-up. Repeat MRI brain one week later showed enhancement in the left cerebral cortex. IVIG was started due to concern for autoimmune encephalitis. Repeat lumbar puncture was positive for La Crosse virus IgM. DISCUSSION: This is the first case of La Crosse encephalitis (LACe) reported in Rhode Island.1 La Crosse virus (LACv) is a ssRNA Bunyavirus transmitted by the eastern tree-hole mosquito typically between July and September. LACv is endemic to the upper Midwestern US and Appalachia. In 2018, 81 of 86 total cases reported by the CDC were pediatric. Children are more likely to present with vomiting, seizures, and focal cortical inflammation or cerebral edema on brain imaging. IgM may be negative early in the disease course. Treatment is antiepileptics and supportive care.

Jamestown Canyon virus encephalitis in a heart transplant patient.

Jamestown Canyon virus (JtCV) is an arbovirus and a member of the California serogroup. To our knowledge, all the cases of JtCV have been reported in immunocompetent patients since it was first detected in 1997. We report a case of JtCV encephalitis in a solid organ transplant patient. A 48-year-old woman from Wisconsin had multiple hospital admissions for symptoms of progressive confusion, visual hallucinations, and inability to perform self-care. Initial evaluation was significant for lymphocytes in cerebrospinal fluid (CSF), and multiple infectious and metabolic causes were excluded. Further investigation found JtCV IgM in serum, and CSF. The patient's clinical course was compatible with JtCV encephalitis, and she was treated with ribavirin in addition to reduction of her immunosuppressive medications. She showed gradual and significant improvement in her mental and functional status. JtCV can cause a variety of symptoms that range from a flu-like syndrome to encephalitis. There have been an increased number of reported cases in recent years which is attributed to increased physician awareness and the availability of laboratory testing. Optimal treatment is still not known.

Effect of the type of milking on mammary gland examination in Saanen goats / Efeito do tipo de ordenha sobre o exame da glândula mamária de cabras Saanen

This research evaluated the effect of milking on the physical exam of the mammary gland (MG) and milk examination in Saanen goats. Six properties were selected, four farms were used after evaluation of criteria selection and distributed in two groups according to the milking method: manual or mechanical. The physical examination of MG was performed using the techniques of inspection and palpation, in addition to the examination of the milk by strip cup, California Mastitis Test, somatic cell count, and bacteriological exam. It was possible to detect an association between the milking method with the most of physical exam of the MG: inspection of the MG (p = 0.001), inspection of the teat (p = 0.002), palpation of the MG (p = 0.054) and palpation of the teat (p = 0.036). The machine milking had an association with the reduction of the volume of MG (OR = 6.00), reduction of the teat size (OR = 16.19), and firm consistency of mammary parenchyma (OR = 2.39). The use of machine milking represented a less risk for an increase of the volume of the MG volume (OR = 0.288) and the presence of cisternitis (OR = 0.490). The association between the SCC and the type of milking was also detected (p = 0.002). Machine milking was associated with changesin the physical exam of MG and milk examination compatible with traumatic lesions. This information indicates inappropriate use of milking equipment in the dairy goat's properties.(AU)

Esta pesquisa avaliou o efeito da ordenha sobre o exame físico da glândula mamária (GM) e do leite em cabras Saanen. Seis propriedades foram selecionadas, quatro fazendas foram utilizadas após avaliação da seleção dos critérios e distribuídas em dois grupos de acordo com o método de ordenha: manual ou mecânico. O exame físico da GM foi realizado utilizando as técnicas de inspeção e palpação, além do exame do leite pelo teste da caneca de fundo escuro, California Mastitis Test, contagem de células somáticas e exame bacteriológico. Foi possível detectar uma associação entre o método de ordenha com a maioria dos exames físicos da GM: inspeção da GM (p = 0,001), inspeção do teto (p = 0,002), palpação da GM (p = 0,054) e palpação do teto (p = 0,036). A ordenha mecânica associou-se com a redução do volume de GM (OR = 6,00), redução do tamanho do teto (OR = 16,19) e consistência firme do parênquima mamário (OR = 2,39). O uso da ordenha mecânica representou menor risco para o aumento do volume do volume da GM (OR = 0,288) e presença da cisternite (OR = 0,490). Também foi detectada a associação entre a CCS e o tipo de ordenha (p = 0,002). A ordenha mecânica foi associada com as alterações no exame físico de GM e do leite compatíveis com lesões traumáticas. Essas informações indicam o uso inadequado do equipamento de ordenha na criação de cabras leiteiras.(AU)

Five Emerging Neuroinvasive Arboviral Diseases: Cache Valley, Eastern Equine Encephalitis, Jamestown Canyon, Powassan, and Usutu.

There are many arthropod-borne viruses (arboviruses) capable of neuroinvasion, with West Nile virus being one of the most well known. In this review, we highlight five rarer emerging or reemerging arboviruses capable of neuroinvasion: Cache Valley, eastern equine encephalitis, Jamestown Canyon, Powassan, and Usutu viruses. Cache Valley and Jamestown Canyon viruses likely circulate throughout most of North America, while eastern equine encephalitis and Powassan viruses typically circulate in the eastern half. Usutu virus is not currently circulating in North America, but has the potential to be introduced in the future given similar climate, vectors, and host species to Europe (where it has been circulating). Health care providers should contact their state or local health departments with any questions regarding arboviral disease surveillance, diagnosis, treatment, or prevention. To prevent neuroinvasive arboviral diseases, use of insect repellent and other mosquito and tick bite prevention strategies are key.

Differences in Neuropathogenesis of Encephalitic California Serogroup Viruses.

The California serogroup of orthobunyaviruses comprises a group of mosquitoborne viruses, including La Crosse (LACV), snowshoe hare (SSHV), Tahyna (TAHV), Jamestown Canyon (JCV), and Inkoo (INKV) viruses, that cause neurologic disease in humans of differing ages with varying incidences. To determine how the pathogenesis of these viruses differs, we compared their ability to induce disease in mice and replicate and induce cell death in vitro. In mice, LACV, TAHV, and SSHV induced neurologic disease after intraperitoneal and intranasal inoculation, and JCV induced disease only after intranasal inoculation. INKV rarely induced disease, which correlated with less viral antigen in the brain than the other viruses. In vitro, all viruses replicated to high titers; however, LACV, SSHV, and TAHV induced high cell death, whereas JCV and INKV did not. Results demonstrated that CSG viruses differ in neuropathogenesis in vitro and in vivo, which correlates with the differences in pathogenesis reported in humans.

Enhanced Arboviral Surveillance to Increase Detection of Jamestown Canyon Virus Infections, Wisconsin, 2011-2016.

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.

Risk factors associated with seropositivity to California serogroup viruses in humans and pet dogs, Quebec, Canada.

Jamestown Canyon and snowshoe hare viruses are two emerging human pathogens associated with cases of neuroinvasive disease in North America. This study aimed to identify environmental and individual risk factors for seropositivity to these arboviruses in humans and pet dogs from Québec, Canada, 2012-2014. In humans, areas with moderate densities of white-tailed deer (Odocoileus virginianus) were associated with higher odds of seropositivity compared with areas with low densities of white-tailed deer (OR 2.50, P = 0.009) and odds of seropositivity were higher in males than in females (OR 2.03, P = 0.016). Among humans reporting more than 10 mosquito bites weekly, the odds of being seropositive were 4.44 times higher (P = 0.004) for people living in hardwood forested areas. Exposure to areas with coniferous forests was identified as the main environmental risk factor for seroconversion in dogs (OR 2.39, P = 0.04). These findings may help target further public health research, diagnostic and surveillance efforts in Canada.

California Serogroup Virus Infection Associated with Encephalitis and Cognitive Decline, Canada, 2015.

California serogroup (CSG) viruses, such as Jamestown Canyon and snowshoe hare viruses, are mosquitoborne pathogens that cause febrile illness and neurologic disease. Human exposures have been described across Canada, but infections are likely underdiagnosed. We describe a case of neuroinvasive illness in a New Brunswick, Canada, patient infected with a CSG virus.

Comparative sequence analyses of La Crosse virus strain isolated from patient with fatal encephalitis, Tennessee, USA.

We characterized a La Crosse virus (LACV) isolate from the brain of a child who died of encephalitis-associated complications in eastern Tennessee, USA, during summer 2012. We compared the isolate with LACV sequences from mosquitoes collected near the child's home just after his postmortem diagnosis. In addition, we conducted phylogenetic analyses of these and other sequences derived from LACV strains representing varied temporal, geographic, and ecologic origins. Consistent with historical findings, results of these analyses indicate that a limited range of LACV lineage I genotypes is associated with severe clinical outcomes.

Neuroinvasive arboviral disease in the United States: 2003 to 2012.

OBJECTIVE: To describe the epidemiologic and clinical syndromes associated with pediatric neuroinvasive arboviral infections among children in the United States from 2003 through 2012. METHODS: We reviewed data reported by state health departments to ArboNET, the national arboviral surveillance system, for 2003 through 2012. Children (<18 years) with neuroinvasive arboviral infections (eg, meningitis, encephalitis, or acute flaccid paralysis) were included. Demographic, clinical syndrome, outcome, geographic, and temporal data were analyzed for all cases. RESULTS: During the study period, 1217 cases and 22 deaths due to pediatric neuroinvasive arboviral infection were reported from the 48 contiguous states. La Crosse virus (665 cases; 55%) and West Nile virus (505 cases; 41%) were the most common etiologies identified. Although less common, Eastern equine encephalitis virus (30 cases; 2%) resulted in 10 pediatric deaths. La Crosse virus primarily affected younger children, whereas West Nile virus was more common in older children and adolescents. West Nile virus disease cases occurred throughout the country, whereas La Crosse and the other arboviruses were more focally distributed. CONCLUSIONS: Neuroinvasive arboviral infections were an important cause of pediatric disease from 2003 through 2012. Differences in the epidemiology and clinical disease result from complex interactions among virus, vector, host, and the environment. Decreasing the morbidity and mortality from these agents depends on vector control, personal protection to reduce mosquito and tick bites, and blood donor screening. Effective surveillance is critical to inform clinicians and public health officials about the epidemiologic features of these diseases and to direct prevention efforts.

La Crosse encephalitis surveillance using single versus paired serologic testing.

We evaluated the validity of single versus paired serologic testing for La Crosse virus (LACV) encephalitis surveillance. Compared with paired serology, a single positive IgG or IgM immunoflourescent antibody titre appears useful for LACV encephalitis surveillance with sensitivity, 75%; specificity, 98%; positive predictive value, 95%; and overall test efficiency 92%.

La Crosse viral infection in hospitalized pediatric patients in Western North Carolina.

OBJECTIVE: La Crosse infection, caused by a rare mosquito-transmitted virus, is endemic in Western North Carolina. Given the large number of cases at our institution, our goal was to describe the presentation, management, and clinical course for pediatric patients with this disease. METHODS: We retrospectively reviewed medical records from pediatric patients with antibody-confirmed La Crosse infection admitted to Mission Hospital July 2004 through August 2009. Demographics, clinical characteristics, management methods, length of hospital stay, and complications were analyzed. Regression analysis was used to assess relationships between presentation and clinical course. RESULTS: Forty-seven pediatric patients were identified with antibody-confirmed La Crosse infection. Seventy percent were male, and the median age was 8 years. Admission signs and symptoms included fever (43%), headache (94%), vomiting (78%), altered mental status (58%), and seizures (61%). All patients had pleocytosis on cerebrospinal fluid studies (range 10-1063 cells/mm3). Median length of stay was 5 days. Seizure at admission was associated with an increased length of stay (2.4 additional days, 95% confidence interval 0.7-4.1). Eighteen patients (38%) received intensive care, 7 (19%) received parenteral or enteral (via nasogastric tube) nutrition, and 4 (9%) received mechanical ventilation. No statistically significant associations between presenting signs and symptoms and complications were found. Treatments included antibiotics (87%), antiviral medication (55%), seizure prophylaxis (47%), and isotonic fluids (98%). CONCLUSIONS: Our data reflect few indicators to predict clinical course during hospital stay. Management strategies should include attention to development of seizure activity and preventive measures for syndrome of inappropriate antidiuretic hormone.

Human Jamestown canyon virus infection --- Montana, 2009.

Jamestown Canyon virus (JCV) is a mosquito-borne zoonotic pathogen belonging to the California serogroup of bunyaviruses. Although JCV is widely distributed throughout temperate North America, reports of human JCV infection in the United States are rare. This is the first report of human JCV infection detected in Montana, one of only 15 cases reported in the United States since 2004, when JCV became reportable. On May 26, 2009, a man aged 51 years with no travel history outside of Montana went to a local emergency department immediately following onset of fever, severe frontal headache, dizziness, left-sided numbness, and tingling. His blood pressure was elevated. Stroke was ruled out, oxygen was administered, medication was prescribed for hypertension, and the patient was sent home. One week later, the patient visited his primary-care physician complaining of continued neurologic symptoms consistent with acute febrile encephalitis and recent mosquito bites. Although West Nile virus (WNV) disease was diagnosed based on detection of WNV-immunoglobulin M (IgM) and G (IgG) antibodies, subsequent testing indicated that the WNV antibodies were from a past infection and that his illness was caused by JCV. The final diagnosis of JCV infection was based on positive JCV-specific IgM enzyme-linked immunosorbent assay (ELISA) results and a fourfold rise in paired sample JCV plaque reduction neutralization test (PRNT) titers. This finding represents a previously unrecognized risk for JCV infection in Montana; clinicians should consider JCV infection when assessing patients for suspected arboviral infections.

The spatial epidemiology and clinical features of reported cases of La Crosse virus infection in West Virginia from 2003 to 2007.

BACKGROUND: La Crosse virus (LACV) is a major cause of pediatric encephalitis in the United States. Since the mid-1980s, the number of reported cases of LACV infection in West Virginia has continued to rise and the state currently reports the most cases in the United States. The purpose of this study was to investigate and describe the spatial epidemiology and clinical presentation of LACV infection cases reported in West Virginia, as well as to provide a description of the environmental conditions present at the residences of the LACV infection cases. METHODS: Descriptive and spatial analyses were performed on LACV infection cases reported to the West Virginia Department of Health from 2003 to 2007. Clinical and environmental variables were available for 96 cases and residence data were available for 68 of these cases. Spatial analyses using the global Moran's I and Kulldorff's spatial scan statistic were performed using the population 15 years and younger at both the county and census tract levels to identify those geographic areas at the highest risk of infection. RESULTS: Two statistically significant (p < 0.05) high-risk clusters, involving six counties, were detected at the county level. At the census tract level, one statistically significant high-risk cluster involving 41 census tracts spanning over six counties was identified. The county level cumulative incidence for those counties in the primary high-risk cluster ranged from 100.0 to 189.0 cases per 100,000 persons (median 189.0) and the census tract level cumulative incidence for those counties in the high-risk cluster ranged from 61.7 to 505.9 cases per 100,000 persons (median 99.0). The counties and census tracts within high-risk clusters had a relative risk four to nine times higher when compared to those areas not contained within high-risk clusters. The majority of LACV infection cases were reported during the summer months in children 15 years and younger. Fever, vomiting, photophobia, and nausea were the most commonly reported signs and symptoms. A case fatality rate (CFR) of 3.1% was observed. Wooded areas and containers were present at the majority of case residences. CONCLUSIONS: The cumulative incidences of LACV infection from 2003 to 2007 were considerably higher than previously reported for West Virginia, and statistically significant high-risk clusters for LACV infection were detected at both the county and census tract levels. The finding of a high CFR and the identification of those areas at highest risk for infection will be useful for guiding future research and intervention efforts.

La Crosse virus neuroinvasive disease - Missouri, 2009.

La Crosse virus (LACV), a California serogroup bunyavirus, is a leading cause of pediatric arboviral encephalitis in the United States and is transmitted primarily by the eastern treehole mosquito (Aedes triseriatus). On August 7, 2009, the Missouri Department of Health and Senior Services (MDHSS) was notified of suspected LACV neuroinvasive disease in a boy aged 8 years from northwest Missouri. Laboratory testing at CDC confirmed LACV infection. An environmental inspection identified multiple vector habitats, including tree holes and discarded tires within a 300-foot radius of the patient's home. Although a median of 67 (range: 29-167) California serogroup virus neuroinvasive disease cases have been reported annually in the United States since 1964, mostly from upper Midwestern and mid-Atlantic states, this is the first reported case of LACV neuroinvasive disease in Missouri since 2002. Ae. triseriatus is found throughout Missouri and as far west as central Kansas and eastern Nebraska. Health-care providers serving this region should maintain a high clinical suspicion for LACV among patients with unexplained meningoencephalitis occurring during summer and fall.

Micromodification of virus-neutralisation assay with vital staining in 96-well plate and its use in diagnostics of Tahyna virus infections.

Virus neutralization test (VNT) is considered to be the gold standard for arbovirus serology because of its high specificity and sensitivity. Its micromodification in 96-well plate with vital staining of cell cultures was developed in the National Reference Laboratory (NRL) for Arboviruses of the Czech Republic and is used for the detection of specific antibodies against various viruses, mainly arboviruses. The test procedure is described for the Tahyna virus micromodified neutralization assay in 96-well plate. Results of an anti-Tahyna antibody survey conducted among the population of northern Moravia using the VNT assay are presented. The overall anti-Tahyna seroprevalence among 1001 tested persons was 3.80%. The highest positivity rate was found in persons aged over 59 years (17.53%) comparing to children with the seroprevalence rates of 0.00% and 0.56% in the age groups 0-5 years and 6-14 years, respectively.