Potential Role of Deer Tick Virus in Powassan Encephalitis Cases in Lyme Disease–endemic Areas of New York,USA

Powassan virus, a member of the tick-borne encephalitis group of flaviviruses, encompasses 2 lineages with separate enzootic cycles. The prototype lineage of Powassan virus (POWV) is principally maintained between Ixodes cookei ticks and the groundhog (Marmota momax) or striped skunk (Mephitis mephitis), whereas the deer tick virus (DTV) lineage is believed to be maintained between Ixodes scapularis ticks and the white-footed mouse (Peromyscus leucopus). We report 14 cases of Powassan encephalitis from New York during 2004–2012. Ten (72%) of the patients were residents of the Lower Hudson Valley, a Lyme disease–endemic area in which I. scapularis ticks account for most human tick bites. This finding suggests that many of these cases were caused by DTV rather than POWV. In 2 patients, DTV infection was confirmed by genetic sequencing. As molecular testing becomes increasingly available, more cases of Powassan encephalitis may be determined to be attributable to the DTV lineage.     

The emergence of human Powassan virus infection in North America

Powassan virus (POWV) is a tickborne flavivirus discovered in Ontario, Canada in 1958 that causes long-term neurological sequelae in about half the reported cases and death in a little more than 10 % of cases. The incidence of POWV disease is rising in the United States but there is limited understanding of the scope and causes of recent changes in POWV epidemiology. We focus on quantifying the increase in human POWV disease incidence and infection prevalence in the United States. We also examine differences in the frequency of symptomatic cases and asymptomatic or mildly symptomatic cases, as well as limitations in national and state surveillance for POWV infection. We searched SCOPUS for all articles containing original POWV prevalence research, case studies, or literature reviews published in English. Case studies were supplemented by Morbidity and Mortality Weekly Report POWV data from the Centers for Disease Control and Prevention (CDC) and surveillance information from state health department websites. An increase in the number of POWV cases has been reported in the United States over the past 50 yr, and the geographic range of human POWV cases has expanded. The age distribution of symptomatic POWV cases has shifted, with significantly more individuals over 40 yr old being diagnosed after 1998. The emergence of POWV is due in large part to: (i) a change in transmission of POWV from a vector that rarely bites people (Ixodes cookei) to a new vector that often bites people (Ixodes scapularis) and has expanded its geographic range, (ii) enhanced surveillance efforts for arboviruses, and (iii) a greater awareness of POWV infection.     

Serologic Survey of Plague in Animals,Western Iran

Disease caused by Powassan virus (POWV), a tick-borne flavivirus, ranges from asymptomatic to severe neurologic compromise and death. Two cases of POWV meningoencephalitis in New York, USA, highlight diagnostic techniques, neurologic outcomes, and the effect of POWV on communities to which it is endemic.     

West nile virus disease and other arboviral diseases - United States, 2011

Arthropodborne viruses (arboviruses) are transmitted to humans primarily through the bites of infected mosquitoes and ticks. Symptomatic infections most often manifest as a systemic febrile illness and, less commonly, as neuroinvasive disease (e.g., meningitis, encephalitis, or acute flaccid paralysis). West Nile virus (WNV) is the leading cause of domestically acquired arboviral disease in the United States. However, several other arboviruses also cause seasonal outbreaks and sporadic cases. In 2011, CDC received reports of 871 cases of nationally notifiable arboviral diseases (excluding dengue); etiological agents included WNV (712 cases), La Crosse virus (LACV) (130), Powassan virus (POWV) (16), St. Louis encephalitis virus (SLEV) (six), Eastern equine encephalitis virus (EEEV) (four), and Jamestown Canyon virus (JCV) (three). Of these, 624 (72%) were classified as neuroinvasive disease, for a national incidence of 0.20 per 100,000 population. WNV and other arboviruses continue to cause focal outbreaks and severe illness in substantial numbers of persons in the United States.     

West Nile virus disease and other arboviral diseases--United States, 2010

Arthropod-borne viruses (arboviruses) are transmitted to humans primarily through the bites of infected mosquitoes and ticks. Since West Nile virus (WNV) was first detected in the Western Hemisphere in 1999, it has become the leading cause of neuroinvasive arboviral disease in the United States. However, several other arboviruses continue to cause sporadic cases and seasonal outbreaks of neuroinvasive disease (i.e., meningitis, encephalitis, or acute flaccid paralysis). This report summarizes surveillance data reported to CDC in 2010 for WNV and other nationally notifiable arboviruses (excluding dengue, which is reported separately). In 2010, 40 states and the District of Columbia (DC) reported 1,021 cases of WNV disease. Of these, 629 (62%) were classified as WNV neuroinvasive disease, for a national incidence of 0.20 per 100,000 population. States with the highest incidence were Arizona (1.60), New Mexico (1.03), Nebraska (0.55), and Colorado (0.51). After WNV, the next most commonly reported cause of neuroinvasive arboviral disease was California serogroup viruses (CALV), with 68 cases, followed by eastern equine encephalitis virus (EEEV), 10 cases, St. Louis encephalitis virus (SLEV), eight cases, and Powassan virus (POWV), eight cases. WNV and other arboviruses continue to cause focal outbreaks and severe illness in substantial numbers of persons in the United States. Maintaining surveillance remains important to guide arboviral disease prevention activities.     

Equine West Nile encephalitis, United States

After the 1999 outbreak of West Nile (WN) encephalitis in New York horses, a case definition was developed that specified the clinical signs, coupled with laboratory test results, required to classify cases of WN encephalitis in equines as either probable or confirmed. In 2000, 60 horses from seven states met the criteria for a confirmed case. The cumulative experience from clinical observations and diagnostic testing during the 1999 and 2000 outbreaks of WN encephalitis in horses will contribute to further refinement of diagnostic criteria.     

Notes from the field: Measles outbreak--Hennepin County, Minnesota, February-March 2011

On March 2, 2011, the Minnesota Department of Health (MDH) confirmed measles in a Hennepin County resident aged 9 months. As of April 1, investigation of contacts and heightened surveillance had revealed a total of 13 epidemiologically linked cases in Hennepin County residents. Of those cases, 11 were laboratory confirmed, and two were in household contacts of confirmed cases and met the clinical case definition for measles.     

Active Case Finding of Current Bornavirus Infections in Human Encephalitis Cases of Unknown Etiology,Germany, 2018–2020

Human bornavirus encephalitis is a severe and often fatal infection caused by variegated squirrel bornavirus 1 (VSBV-1) and Borna disease virus 1 (BoDV-1). We conducted a prospective study of bornavirus etiology of encephalitis cases in Germany during 2018–2020 by using a serologic testing scheme applied along proposed graded case definitions for VSBV-1, BoDV-1, and unspecified bornavirus encephalitis. Of 103 encephalitis cases of unknown etiology, 4 bornavirus infections were detected serologically. One chronic case was caused by VSBV-1 after occupational-related contact of a person with exotic squirrels, and 3 acute cases were caused by BoDV-1 in virus-endemic areas. All 4 case-patients died. Bornavirus etiology could be confirmed by molecular methods. Serologic testing for these cases was virus specific, discriminatory, and a practical diagnostic option for living patients if no brain tissue samples are available. This testing should be guided by clinical and epidemiologic suspicions, such as residence in virus-endemic areas and animal exposure.     

Autochthonous Cases of Tick-Borne Encephalitis,Belgium, 2020

We report 3 confirmed autochthonous tick-borne encephalitis cases in Belgium diagnosed during summer 2020. Clinicians should include this viral infection in the differential diagnosis for patients with etiologically unexplained neurologic manifestations, even for persons without recent travel history.     

Nipah Virus Infection Outbreak with Nosocomial and Corpse-to-Human Transmission,Bangladesh

Active Nipah virus encephalitis surveillance identified an encephalitis cluster and sporadic cases in Faridpur, Bangladesh, in January 2010. We identified 16 case-patients; 14 of these patients died. For 1 case-patient, the only known exposure was hugging a deceased patient with a probable case, while another case-patient’s exposure involved preparing the same corpse for burial by removing oral secretions and anogenital excreta with a cloth and bare hands. Among 7 persons with confirmed sporadic cases, 6 died, including a physician who had physically examined encephalitis patients without gloves or a mask. Nipah virus–infected patients were more likely than community-based controls to report drinking raw date palm sap and to have had physical contact with an encephalitis patient (29% vs. 4%, matched odds ratio undefined). Efforts to prevent transmission should focus on reducing caregivers’ exposure to infected patients’ bodily secretions during care and traditional burial practices.     

Molecular Epidemiology of Blastomyces gilchristii Clusters,Minnesota, USA

We characterized 2 clusters of blastomycosis cases in Minnesota, USA, using whole-genome sequencing and single-nucleotide polymorphism analyses. Blastomyces gilchristii was confirmed as the cause of infection. Genomic analyses corresponded with epidemiologic findings for cases of B. gilchristii infections, demonstrating the utility of genomic methods for future blastomycosis outbreak investigations.     

A Clustering of Immune-mediated Polyradiculoneuropathy among Swine Abattoir Workers Exposed to Aerosolized Porcine Brains,Indiana, United States

Abstract

In November 2007 a novel neuropathy, immune-mediated polyradiculoneuropathy (IP), was identified among workers at a Minnesota swine abattoir where a unique compressed air technique was used to remove porcine brains. An epidemiologic investigation at another abattoir in Indiana that also uses this process was launched to evaluate workers self-reporting neurologic illness compatible with IP. A nested case-control study was performed to identify cases and risk factors. Six confirmed, one probable, and three possible IP cases were detected. IP cases were 28–52 years old, of Latino origin, and 62.5% female. Onset dates ranged from April 2005–December 2007; 60% were hospitalized. IP cases at this plant were similar in clinical presentation and exposure risks to those detected in Minnesota. Swine abattoirs using similar brain extraction methods should discontinue this process.     

广西急性脑炎脑膜炎症候群的监测与研究

目的 系统监测急性脑炎脑膜炎症候群患者,分析其流行病学特征、病原谱构成,为科学防治脑炎脑膜炎症候群提供依据.方法 在人口约502万的广西贵港市建立急性中枢神经系统感染的症候群监测系统,开展血液和脑脊液标本的细菌学培养、乳胶凝集试验、实时荧光PCR、ELISA 等多种实验室检测,完成患者入院、出院2次流行病调查,按照WHO监测手册的患者定义将疑似患者分为流行性乙型脑炎(简称乙脑)、细菌性脑炎、可能的病毒性脑炎等6个分类,分析其流行病学特征.通过对比临床诊断与实验室检测结果评估症候群监测系统的收益.结果 在30个月的监测期内,共评估急性脑炎脑膜炎症候群患者1424例,报告年均临床发病率、死亡率、病死率分别为11.35/10万(1424/12 546 500人年)、0.43/10万(54/12 546 500人年)、3.79%(54/1424);病原学确诊154例,其中乙脑103例、细菌性脑炎51例,估算年发病率分别为0.82/10万(103/12 546 500人年)、0.41/10万(51/12 546 500人年);96.10%(99/103)的乙脑患者为10岁以下儿童,37.30%(19/51)的细菌性脑膜炎发生在5岁以下儿童中.乙脑、细菌性脑膜炎的临床误诊率分别为19.42%(20/103)和15.69%(8/51).结论 急性脑炎脑膜炎症候群病原以病毒性为主,急性脑炎脑膜炎症候群主要危害10岁以下散居儿童,当前脑炎、脑膜炎的临床诊断存在一定比例的误诊.

Abstract：

Objective To estimate disease burden and epidemiological characteristics of acute meningitis/encephalitis,and provide the basis for the disease control strategy development.Methods A syndrome surveillance system was established in Guigang city with a population of 5 020 000.For the suspected cases, serum and CSF were collected,and bacterial culture,latex agglutination test,real-time PCR and ELISA tests were carried out. All involved cases were identified to 6 categories according to WHO case definition. Results 1424 suspected cases were evaluated in a surveillance of 30 months,yielding the incidence,mortality and mortality of 11.35/100 000(1424/12 546 500 person years),0.43/100 000(54/12 546 500 person years),3.79%(54/1424)respectively.A total of 103 and 51 cases were confirmed for JE,bacterial meningitis,with a incidence of 0.82/100 000(103/12 546 500 person years),0.41/100 000(51/12 546 500 person years).96.10%(99/103)of JE sases and 37.30%(19/51)bacterial meningitis cages occurred in＜10 years old children and＜5 years old children.A clinical misdiagnosis rate of 19.42%(20/103)and 15.69%(8/51)were obserred for JE and bacterial meningitis.Conclusion Acute encephalitis,meningitis syndrome can cause a higher burden of disease.of which the main components of viral encephalitis.Most of syndrome is occurred in summer and autumn,mainly reported in children of younger than 10 years old.A quite misdiagnosis would be made among meningitis and encephalitis syndrome cases.     

Change in Japanese encephalitis virus distribution, Thailand

Japanese encephalitis virus (JEV) genotypes in Thailand were studied in pigs and mosquitoes collected near houses of confirmed human JEV cases in 2003-2005. Twelve JEV strains isolated belonged to genotype I, which shows a switch from genotype III incidence that started during the 1980s.     

Dengue virus type 3, Brazil, 2002

During the summer of 2002, Rio de Janeiro had a large epidemic of dengue fever; 288,245 cases were reported. A subset of 1,831 dengue hemorrhagic fever cases occurred. In this study, performed in the first half of 2002, samples from 1,559 patients with suspected cases of dengue infection were analyzed. From this total, 1,497 were obtained from patients with nonfatal cases, and 62 were obtained from patients with fatal cases. By the use of different methods, 831 (53.3%) cases, including 40 fatal cases, were confirmed as dengue infection. When virus identification was successful, dengue virus type 3 (DENV-3) was obtained in 99% of cases. Neurologic involvement was shown in 1 patient with encephalitis, confirmed by the detection of DENV-3 RNA in the cerebrospinal fluid. This explosive epidemic of DENV-3 was the most severe dengue epidemic reported in Brazil since dengue viruses were introduced in 1986.     

2007-2014年肇庆市流行性乙型脑炎流行特点 及健康人群抗体水平调查

摘要:目的　了解肇庆市2007-2014年流行性乙型脑炎（简称乙脑）流行特点及健康人群乙脑病毒抗体水平。方法　对肇庆市2007-2014年乙脑患者资料进行描述性流行病学分析,对2012-2014年采集的怀集县和封开县共608份健康人群血清标本进行乙脑IgG抗体检测,运用分析性流行病学方法进行分析。结果　2007年以来,肇庆市共报告117例乙脑疑似病例,经实验室确诊80例,其中死亡4例,年均发病率为0.24/10万。发病时间集中在5-7月,6月份为发病高峰;疫情主要分布在怀集县;乙脑病例以1～14岁儿童为主;确诊病例中无明确乙脑疫苗免疫史者占81.25%（65/80）;怀集县健康人群乙脑IgG抗体阳性率为85.76%（259/302）,封开县为62.75%（192/306）,2县抗体阳性率在不同年龄段、城乡之间比较有统计学差异。结论　肇庆市乙脑流行呈现明显的季节性和一定的地域性,14岁以下儿童为易感人群,封开县健康人群乙脑IgG抗体阳性率较怀集县要低;应及时为适龄儿童接种乙脑疫苗,做好防蚊灭蚊,强化疾病监测相关工作,控制乙脑流行。     

Human rabies--Minnesota, 2007

On October 20, 2007, a Minnesota resident died from rabies, approximately 1 month after initial symptoms of limb paresthesia, which progressed to flaccid weakness and ataxia. This was the only human rabies case reported in the United States in 2007. A presumptive diagnosis of idiopathic transverse myelitis was considered initially, because of abnormalities detected via spinal cord imaging studies and a lack of laboratory confirmation of a specific infectious etiology. The presumptive diagnosis subsequently was changed to include rabies, based on the patient's rapidly deteriorating neurologic status and elicitation of a history involving bat exposure during the month before illness onset. This report summarizes the medical and epidemiologic investigation by the Minnesota Department of Public Health and CDC and the ensuing public health response. The findings underscore the need for early inclusion of rabies in the differential diagnosis of rapidly progressive encephalitis, improved public awareness of the risks associated with animal bites, and appropriate rabies prophylaxis after exposure.     

Incidence of pelvic endometriosis in Rochester, Minnesota, 1970-1979

To the authors' knowledge, the incidence pelvic endometriosis in the general female population has not been previously reported. The purpose of the present study was to determine the incidence rate of diagnosed pelvic endometriosis among white females of reproductive age (15-49 years) in Rochester, Minnesota, during 1970-1979. Incidence rates were prepared first with histologically confirmed cases alone and then with the successive inclusion of progressively less certain cases: surgically visualized, clinically probable, and clinically possible. The overall incidence of pelvic endometriosis more than doubled (from 108.8 to 246.9 cases per 100,000 person-years) as the definition of a case was extended from histologically confirmed cases alone to all cases. Age-specific incidence rates increased in successive age groups through age 44 and then declined for women 45-49 years of age. Methodological problems in the definition and ascertainment of incident cases of pelvic endometriosis are described in detail.     

The use of acyclovir in suspected encephalitis.

The early use of intravenous acyclovir in herpes simplex encephalitis (HSE) is essential. However, rapid diagnostic tests are not freely available. Hence, all patients with suspected encephalitis may need to be commenced on acyclovir. In our study, of 34 patients with suspected encephalitis, only two eventually had HSE confirmed, 19 had encephalitis not due to herpes simplex and in 13 a non-encephalitis illness was finally diagnosed. Guidelines for the use of acyclovir in suspected encephalitis are given aimed at minimizing the drug cost whilst still protecting all cases of presumed HSE.