2773. Safety and Immunogenicity Study of Eastern Equine Encephalitis Vaccine

Abstract Background Eastern equine encephalitis virus (EEEV) is an alphavirus with a high mortality rate and serious neurological sequelae in infected persons making this virus an important human pathogen. Methods Following written informed consent, eligible subjects received two priming doses of EEEV vaccine, inactivated, TSI-GSD 104, 0.5 mL subcutaneously on days 0 and 28 days followed by a mandatory booster, 0.1 mL intradermal, at 6 months. Serum samples were collected pre-vaccination, days 21–35 following dose 2, as well as before and 21–35 days after dose 3. Sera with a Plaque Reduction Neutralization Test80 titer (PRNT80) ≥ 1:40 were considered responders with adequate titers for the purpose of biocontainment suite entry. Results Sixty-seven (67) subjects were enrolled in this study to receive the primary vaccination series. All 67 subjects received at least 1 primary vaccination; 66 completed the 2 primary doses; 58 completed the 2 primary doses and the 6-month dose. Of these, 38 (56.7%) reported one or more adverse events. Fatigue was reported in 13 (19.4%), headache in 9 (13.4%), upper respiratory tract infection in 6 (9.0%), nausea in 5 (7.5%), pyrexia in 5 (7.5%), oropharyngeal pain in 4 (6.0%), myalgia in 4 (6.0%), injection site pain in 7 (10.4%), injection site hematoma in 4 (6.0%) and injection site erythema in 3 (4.5%) subjects. Adverse events were mostly mild or moderate and transient. PRNT80 titers ≥ 1:40 was observed in 39/65 (60%) subjects who received both primary doses of EEEV vaccine compared with 48/57 (84%) subjects who completed the 2-dose primary series and the 6-month dose and also had blood drawn for titer. Females had a higher response rate (61.5%) at the pre 6-month boost titer than did males (34.3%) (p = 0.0231). Similarly, the pre 6-month boost geometric mean titer (GMT) for females was 35.5 vs. 21.9 for males (p = 0.0231). The post 6-month boost GMT for females was 146.7 and 181.5 for males (P = 0.13). Conclusion Inactivated Eastern Equine Encephalitis Virus vaccine, TSI-GSD 104, Lot 2-1-89 appears to be safe and immunogenic. This Phase 2 vaccine study supports a priming dose schedule of Days 0 and 28 and 6-month. The 6 month dose is anamnestic improving the overall response rate and level of antibody for this primary dosing schedule. Disclosures All authors: No reported disclosures.

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Eastern equine encephalitis virus detected in Florida

AccessScience ◽

10.1036/1097-8542.br0802191 ◽

2019 ◽

Keyword(s):

Encephalitis Virus ◽

Eastern Equine Encephalitis Virus ◽

Eastern Equine Encephalitis ◽

Equine Encephalitis Virus

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Fractionation of Eastern Equine Encephalitis Virus by Density Gradient Centrifugation in CsCl

Journal of Virology ◽

10.1128/jvi.2.10.972-978.1968 ◽

1968 ◽

Vol 2 (10) ◽

pp. 972-978 ◽

Cited By ~ 5

Author(s):

H. G. Aaslestad ◽

E. J. Hoffman ◽

Arthur Brown

Keyword(s):

Density Gradient ◽

Density Gradient Centrifugation ◽

Gradient Centrifugation ◽

Encephalitis Virus ◽

Eastern Equine Encephalitis Virus ◽

Eastern Equine Encephalitis ◽

Equine Encephalitis Virus

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49. Clinical Characteristics of the 2019 Eastern Equine Encephalitis Virus Outbreak in Michigan

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.359 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S154-S154

Author(s):

Adam T Ladzinski ◽

Matthew T Rumschlag ◽

Aditya Mehta ◽

Eric Edewaard ◽

Pimpawan Boapimp ◽

...

Keyword(s):

Clinical Symptoms ◽

The United States ◽

Encephalitis Virus ◽

Eastern Equine Encephalitis Virus ◽

Radiographic Images ◽

Eastern Equine Encephalitis ◽

Male Predominance ◽

Equine Encephalitis Virus ◽

Neuroinvasive Disease ◽

Neurologic Sequelae

Abstract Background Eastern Equine Encephalitis Virus (EEEV) is a mosquito-borne alphavirus responsible for unpredictable outbreaks of severe neurologic disease in humans. While the vast majority of human EEEV infections are either asymptomatic or clinically nonspecific, a minority of patients develops neuroinvasive disease (EEE), which is a devastating illness with a mortality of at least 30%. No treatments are known to be effective. EEEV infection is relatively rare in the United States, with an annual average nationwide incidence of 7 cases between 2009 and 2018. However, 2019 was an exceptionally active year for human EEEV disease, yielding 38 nationwide confirmed cases, including 10 in Michigan, comprising the state’s largest outbreak to date. Methods EEE cases were identified by a regional network of physicians. Cases were defined by presentation with clinical symptoms of encephalitis, and by identification of EEEV IgM antibodies or RNA in cerebrospinal fluid (CSF), or EEEV-specific IgM in serum as confirmed by plaque reduction neutralization test. Radiographic images were evaluated and clinical data abstracted through chart review and clinical follow-up where possible. Results Records from 7 patients were identified and reviewed. The median age was 64, with a male predominance, and all presented in August. Notably, commercial arboviral CSF serology was uniformly negative on the initial CSF sample, and diagnosis was not made until a mean of 23 days (range: 12–38 days) after presentation. Testing in public health laboratories yielded the diagnosis in 5 out of 7 cases. Imaging findings were heterogeneous, but most patients exhibited abnormal findings in the thalamus and/or basal ganglia, and one patient displayed prominent pons and midbrain abnormalities. 4 patients died, while 2 patients survived with severe neurologic sequelae, and 1 patient recovered without sequelae. One patient underwent a limited postmortem examination, which revealed diffuse meningoencephalitis and focal vascular necrosis. Conclusion EEE is a frequently fatal condition whose diagnosis is often delayed, and for which no effective treatments are known. Improved diagnostics are needed to facilitate further clinical studies of EEE and encourage the development of potential therapies. Disclosures All Authors: No reported disclosures

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Active Circulation of Madariaga Virus, a Member of the Eastern Equine Encephalitis Virus Complex, in Northeast Brazil

Pathogens ◽

10.3390/pathogens10080983 ◽

2021 ◽

Vol 10 (8) ◽

pp. 983

Author(s):

Laura H. V. G. Gil ◽

Tereza Magalhaes ◽

Beatriz S. A. S. Santos ◽

Livia V. Oliveira ◽

Edmilson F. Oliveira-Filho ◽

...

Keyword(s):

Phylogenetic Analyses ◽

Case Fatality ◽

Febrile Illness ◽

Encephalitis Virus ◽

Northeast Brazil ◽

Eastern Equine Encephalitis Virus ◽

Eastern Equine Encephalitis ◽

Vaccination Programs ◽

Transmission Cycle ◽

Equine Encephalitis Virus

Madariaga virus (MADV) is a member of the eastern equine encephalitis virus (EEEV) complex that circulates in Central and South America. It is a zoonotic, mosquito-borne pathogen, belonging to the family Togaviridae. Disturbances in the natural transmission cycle of this virus result in outbreaks in equines and humans, leading to high case fatality in the former and acute febrile illness or neurological disease in the latter. Although a considerable amount of knowledge exists on the eco-epidemiology of North American EEEV strains, little is known about MADV. In Brazil, the most recent isolations of MADV occurred in 2009 in the States of Paraíba and Ceará, northeast Brazil. Because of that, health authorities have recommended vaccination of animals in these regions. However, in 2019 an equine encephalitis outbreak was reported in a municipality in Ceará. Here, we present the isolation of MADV from two horses that died in this outbreak. The full-length genome of these viruses was sequenced, and phylogenetic analyses performed. Pathological findings from postmortem examination are also discussed. We conclude that MADV is actively circulating in northeast Brazil despite vaccination programs, and call attention to this arbovirus that likely represents an emerging pathogen in Latin America.

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Mapping Eastern Equine Encephalitis Virus Risk on Equestrian Trails in Florida State Parks

Journal of Park and Recreation Administration ◽

10.18666/jpra-2021-10447 ◽

2021 ◽

Author(s):

Joni Downs ◽

Mehrdad Vaziri ◽

Abigail Lavallin ◽

Kristi Miley

Keyword(s):

Risk Model ◽

Risk Index ◽

Management Strategies ◽

Encephalitis Virus ◽

Transmission Risk ◽

State Parks ◽

Eastern Equine Encephalitis Virus ◽

Eastern Equine Encephalitis ◽

Equine Encephalitis Virus ◽

Index Model

Equestrian trail riding is a popular recreational activity but can expose horses and riders to arboviral diseases, such as Eastern Equine Encephalitis Virus (EEEV). This study uses a geographic information system (GIS) -based risk index model to measure and map risk associated with EEEV transmission to horses on equine trails in State Parks across Florida. The risk model assesses EEEV transmission risk of individual trail locations on a continuous scale of 0.0 (no measurable risk) to 1.0 (maximal risk). Risk is evaluated based on the composition and configuration of habitat types that support vectors and hosts of the virus. The results suggest that visitors using equestrian trails in the Florida State Park System may potentially be exposed to high levels of EEEV risk during times that the virus is actively circulating. Accordingly, park management strategies are recommended for reducing transmission risk to both horses and riders in areas where risk is high.

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