Year-round West Nile virus activity, Gulf Coast region, Texas and Louisiana

West Nile virus (WNV) was detected in 11 dead birds and two mosquito pools collected in east Texas and southern Louisiana during surveillance studies in the winter of 2003 to 2004. These findings suggest that WNV is active throughout the year in this region of the United States.     

Acute Encephalitis Hospitalizations,California, 1990–1999: Unrecognized Arboviral Encephalitis?

Historically, Western equine encephalomyelitis and St. Louis encephalitis caused substantial human and equine illness and death in California. This study describes the epidemiology of encephalitis with data from 13,807 patients hospitalized in California with acute encephalitis from 1990 through 1999. The incidence of encephalitis hospitalizations decreased over this period. The greatest proportion of case-patients was hospitalized in the winter. Encephalitis of unspecified origin was the most common diagnosis, and arboviral encephalitis was the least common. Some California counties had concurrent increases in encephalitis rates and in detected arboviral activity in sentinel chickens and mosquito vectors. However, a diagnosis of arboviral encephalitis was made for few hospitalized patients in these counties during these periods. Although some arboviral encephalitis cases may have been undiagnosed, such cases probably did not occur frequently. Active hospital-based surveillance during periods of heightened sylvatic arboviral activity could increase detection of arboviral encephalitis.     

福建省2005-2009年流行性乙型脑炎流行病学分析

目的了解福建省2005-2009年流行性乙型脑炎（乙脑）流行病学特征,为制定福建省乙脑监测及控制策略提供依据。方法对2005-2009年福建省乙脑疫情报告资料进行回顾性分析。结果福建省2005-2009年共报告174例乙脑病例,年均发病率0.0980/10万。历年发病率均低于全国同期水平。174例病例发生在除厦门市外的8个地市、57个县。7月份为发病高峰,占总病例的64.94%,其次为6月和8月。83.33%的病例集中在15岁以下儿童,在131例有调查资料的病例中,50.38%无免疫史。结论福建省自2004年将乙脑疫苗纳入儿童计划免疫后,乙脑发病率处于低发水平,控制效果较为显著。在乙脑高发地区必须进一步制定强有力的措施提高乙脑疫苗接种的及时率和全程接种率。     

Venezuelan equine encephalitis virus infection of cotton rats

Venezuelan equine encephalitis virus (VEEV) is an emerging pathogen of equids and humans, but infection of its rodent reservoir hosts has received little study. To determine whether responses to infection vary among geographic populations, we inoculated 3 populations of cotton rats with 2 enzootic VEEV strains (Co97-0054 [enzootic ID subtype] and 68U201 [enzootic IE subtype]). The 3 populations were offspring from wild-caught cotton rats collected in a VEE-enzootic area of south Florida, USA; wild-caught cotton rats from a non-VEE-enzootic area of Texas, USA; and commercially available (Harlan) colony-reared cotton rats from a non-VEE-enzootic region. Although each population had similar early viremia titers, no detectable disease developed in the VEE-sympatric Florida animals, but severe disease and death affected the Texas and Harlan animals. Our findings suggest that the geographic origins of cotton rats are important determinants of the outcome of VEE infection and reservoir potential of these rodents.     

3例流行性出血热危重型临床分析

对３例流行性出血热患者症状、体征、并发病、伴发病及传染媒介、传播途径进行了分析。１例有进食鼠肉史，属消化道传播。城市居民由于体内抗流行性出血热病毒免疫功能低，病毒入侵后，可引起强烈的变态反应，发病率虽低，但危重型多见。神经系统表现为昏迷、神经精神异常、脑出血；并发病有肺部感染、高血压、肠道菌群失调等。２例抢救成功，１例死于脑出血。强调有条件的单位要尽早给予血液透析，采用综合治疗措施。     

Tickborne arbovirus surveillance in market livestock, Nairobi, Kenya

To identify tickborne viruses circulating in Kenya and the surrounding region, we conducted surveillance at abattoirs in Nairobi, Kenya. Species of ticks collected included Rhipicephalus pulchellus (56%), Amblyomma gemma (14%), R. appendiculatus (8%), A. variegatum (6%), and others. A total of 56 virus isolates were obtained, 26 from A. gemma, 17 from R. pulchellus, 6 from A. variegatum, and 7 from other species. Virus isolates included Dugbe virus (DUGV), an unknown virus related to DUGV, Thogoto, Bhanja, Kadam, Dhori, Barur, and foot-and-mouth disease (FMDV) viruses. This is the first report of Dhori virus isolation in East Africa and the first known isolation of FMDV associated with tick collection. Our results demonstrate the potential for tickborne dissemination of endemic and emergent viruses and the relevance of A. gemma in the maintenance of tickborne viruses in this region.     

新疆地区虫媒病毒调查研究状况

近年来新疆陆续发现的一些新的虫媒病毒与虫媒病毒病对当地人畜健康造成一定危害.新疆地理生态环境的复杂多样性为多种虫媒病毒的传播提供了有利条件,虫媒病毒在新疆分布广泛,存在地域差异性.随着分子流行病学的发展,基于核酸分子和细胞培养检测技术方法从新疆的多种昆虫媒介和宿主动物中鉴定并分离得到分属于黄病毒科,披膜病毒科,呼肠孤病毒科和布尼亚病毒科的多种病毒,部分病毒属在新疆系首次发现.本文对新疆多个地区近年来已报道的虫媒病毒在宿主中的检测和感染人畜引起的疾病的情况进行了汇总整理,有利于对新疆各地虫媒病毒的流行病学进行深入的调查与研究.     

Bovine Arboviruses in Culicoides Biting Midges and Sentinel Cattle in Southern Japan from 2003 to 2013

Epizootic congenital abnormalities, encephalomyelitis and febrile illnesses in cattle caused by arthropod‐borne viruses (arboviruses) are prevalent in Japan. Causative viruses including orthobunyaviruses, orbiviruses and rhabdovirus are thought to be transmitted by Culicoides biting midges. Recently, the incursions of several arboviruses, potentially Culicoides‐borne, were newly confirmed in Japan. However, their spread pattern and exact vector species are currently uncertain. Attempts to isolate arboviruses from Culicoides biting midges and sentinel cattle were conducted in Kagoshima, located at the southernmost end of the main islands of Japan, a potentially high‐risk area for incursion of arboviral diseases and outbreak of endemic ones. Seventy‐eight isolates comprising Akabane, Peaton and Sathuperi viruses of the genus Orthobunyavirus of the family Bunyaviridae, bluetongue virus serotype 16, D'Aguilar virus, Bunyip Creek virus and epizootic haemorrhagic disease virus serotype 1 of the genus Orbivirus of the family Reoviridae, a potentially novel rhabdovirus of the genus Ephemerovirus and unidentified orbivirus‐like viruses were obtained from Culicoides biting midges and sentinel cattle between 2003 and 2013. Akabane, Sathuperi, D'Aguilar and Bunyip Creek viruses were selectively isolated from Culicoides oxystoma, suggesting this vector's responsibility for these arbovirus outbreaks. The results of virus isolation also implied that C. tainanus, C. jacobsoni and C. punctatus are competent for the transmission of bluetongue virus serotype 16, Peaton virus and epizootic haemorrhagic disease virus serotype 1, respectively. Our monitoring in Culicoides biting midges and sentinel cattle detected the circulation of Akabane virus just prior to the accumulations of bovine congenital abnormalities and encephalomyelitis by it around study sites in 2003, 2006, 2008 and 2013. Silent circulations of the other arboviruses, including potentially new viruses, were also detected during the study period.     

Schmallenberg virus detection in Culicoides biting midges in Spain: First laboratory evidence for highly efficient infection of Culicoides of the Obsoletus complex and Culicoides imicola

Since Schmallenberg disease was discovered in 2011, the disease rapidly spread across Europe. Culicoides biting midges have been implicated as putative Schmallenberg vectors in Europe. The detection of Schmallenberg virus (SBV) in field collected Culicoides was evaluated through retrospective (2011–2012) collections and captures performed in 2013. This study represents the first detection of SBV in field collected Culicoides in Spain. Infectious midges were detected at the foothills of Pyrenees, Aramunt, in the summer 2012. All the specimens infected with Schmallenberg were of the species Culicoides obsoletus s.s. confirming its putative vector status in Spain. Experimental infection on field collected Culicoides provided evidence of atypical high efficiency for SBV vector infection and transmission potential in local populations of Culicoides imicola and in Culicoides of the Obsoletus complex. However, captured individuals of C. imicola were more susceptible to SBV infection than C. obsoletus s.l. (p  < .001), with an infection ratio of 0.94 and 0.63, respectively. In contrast, a Culicoides nubeculosus colony appeared to be refractory to SBV infection.