In this review, we mainly focus on zoonotic encephalitides caused by arthropod-borne viruses (arboviruses) of the families Flaviviridae (genus Flavivirus) and Togaviridae (genus Alphavirus) that are important in both humans and domestic animals. Specifically, we will focus on alphaviruses (Eastern equine encephalitis virus, Western equine encephalitis virus, Venezuelan equine encephalitis virus) and flaviviruses (Japanese encephalitis virus and West Nile virus). Most of these viruses were originally found in tropical regions such as Africa and South America or in some regions in Asia. However, they have dispersed widely and currently cause diseases around the world. Global warming, increasing urbanization and population size in tropical regions, faster transportation and rapid spread of arthropod vectors contribute in continuous spreading of arboviruses into new geographic areas causing reemerging or resurging diseases. Most of the reemerging arboviruses also have emerged as zoonotic disease agents and created major public health issues and disease epidemics.
Africa ; Alphavirus* ; Animals, Domestic ; Arboviruses* ; Arthropod Vectors ; Asia ; Encephalitis ; Encephalitis Virus, Venezuelan Equine ; Encephalitis Virus, Western Equine ; Encephalitis Viruses ; Encephalomyelitis, Equine ; Epidemiology* ; Flaviviridae ; Flavivirus* ; Global Warming ; Humans ; Population Density ; Public Health ; South America ; Togaviridae ; Transportation ; Urbanization ; Zoonoses

Venezuelan equine encephalitis (VEE) is a zoonotic disease caused by the Venezuelan equine encephalitis virus (VEEV) complex. This disease has not yet been reported in China, and it is therefore essential to establish a rapid and accurate method for detection of the virus in order to prevent and control this disease. In this study, a one-step real-time quantitative RT-PCR method was developed for the detection of the VEEV complex. A pair of specific primers and a Taqman probe were designed corresponding to a conserved region of the VEEV gene nspl, allowing the detection of all known strains of different sub- types of the virus. Using RNA synthesized by in vitro transcription as template, the sensitivity of this method was measured at 3.27 x 10(2) copies/microL. No signal was generated in response to RNA from Chikungunya virus (CHIKV), nor to RNA encoding the nsp1 fragment of Eastern equine encephalitis virus (EE-EV) or Western equine encephalitis virus (WEEV), all of which belong to the same genus as VEEV. This indicates that the method has excellent specificity. These results show that this one-step real-time quantitative RT-PCR method may provide an effective tool for the detection of VEEV in China.
China ; DNA Primers ; genetics ; Encephalitis Virus, Venezuelan Equine ; classification ; genetics ; isolation & purification ; Encephalomyelitis, Venezuelan Equine ; virology ; Humans ; RNA, Viral ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; methods

Alphavirus Infections ; epidemiology ; Chikungunya virus ; Humans

Alphavirus Infections ; diagnosis ; epidemiology ; virology ; Animals ; Chikungunya Fever ; Chikungunya virus ; genetics ; isolation & purification ; physiology ; Humans ; Viral Proteins ; genetics ; metabolism

The incidence of chikungunya infection in Singapore has been on the rise since the first reported case in 2006. Acute polyarthritis, a common manifestation among affected patients, may precede fever and present with debilitating arthritis to rheumatologists, orthopaedists, internists and primary care physicians. The diagnosis of chikungunya infection requires careful history taking and a high index of suspicion, with supporting evidence from the reverse transcription-polymerase chain reaction or the chikungunya IgM serology test. Treatment of chikungunya arthritis usually involves non-steroidal anti-inflammatory drugs. Rarely, polyarthritis in chikungunya may persist even after resolution of the acute infection, necessitating treatment with disease-modifying anti-rheumatic drugs. In this article, we present the different manifestations of chikungunya arthritis in our local setting and review the literature.
Aged ; Alphavirus Infections ; complications ; Anti-Inflammatory Agents, Non-Steroidal ; therapeutic use ; Arthritis ; drug therapy ; virology ; Chikungunya Fever ; Chikungunya virus ; Female ; Humans ; Male ; Middle Aged

Various new technologies have been applied for developing vaccines against various animal diseases. Virus-like particle (VLP) vaccine technology was used for manufacturing the porcine circovirus type 2 and RNA particle vaccines based on an alphavirus vector for porcine epidemic diarrhea (PED). Although VLP is classified as a killed-virus vaccine, because its structure is similar to the original virus, it can induce long-term and cell-mediated immunity. The RNA particle vaccine used a Venezuela equine encephalitis (VEE) virus gene as a vector. The VEE virus partial gene can be substituted with the PED virus spike gene. Recombinant vaccines can be produced by substitution of the target gene in the VEE vector. Both of these new vaccine technologies made it possible to control the infectious disease efficiently in a relatively short time.
Alphavirus ; Animal Diseases ; Animals* ; Circovirus ; Communicable Diseases ; Diarrhea ; Encephalitis Virus, Venezuelan Equine ; Encephalomyelitis, Equine ; Immunity, Cellular ; Porcine epidemic diarrhea virus ; RNA ; Vaccines ; Vaccines, Synthetic ; Vaccines, Virus-Like Particle ; Venezuela

This report describes the chikungunya cases and local transmission detected in Brunei Darussalam for the first time, despite the country being situated in a region that has experienced a multitude of outbreaks over the years. A combined strategy of active case detection, patient isolation and vector control measures was deployed in an attempt to avert further transmission. The findings have important public health implications for international surveillance and control strategies for this re-emerging disease.
Adult ; Alphavirus Infections ; diagnosis ; epidemiology ; transmission ; Brunei ; epidemiology ; Chikungunya Fever ; Disease Outbreaks ; prevention & control ; Female ; Humans ; Male ; Middle Aged ; Population Surveillance

It is clear that exposure to arthropod-borne viruses is common in the populations of both Papua New Guinea and Irian Jaya. Clinical disease resulting from these infections has been reported although the paucity of case reports and combined clinical experience suggest that it is rare. Dengue epidemics due to dengue-1 and dengue-2 have occurred and it is likely that dengue-3 is also present in the region. No cases of dengue haemorrhagic fever have been described. Murray Valley encephalitis, Ross River and antigenically related viruses are widespread in Papua New Guinea and Irian Jaya, particularly in the lowland and coastal areas. Antibodies to Japanese encephalitis virus have not been found in blood samples from Papua New Guinea or Irian Jaya. As Papua New Guinea is developed, new areas of the country are opened up and ecosystems are altered. It is important that physicians based in Papua New Guinea, and those who deal with patients living or working here, are aware of the arbovirus diseases which occur and the potential and preventable problems posed by them to both the individual and the community.
Alphavirus Infections - epidemiology ; Arboviruses ; Dengue - epidemiology ; Papua New Guinea - epidemiology ; Population Surveillance

OBJECTIVETo investigate the effect of Lead (Pb) acetate exposure on Semliki forest virus (SFV) pathogenesis in mice.

METHODSDifferent doses (62.5, 125, 250 and 500 mg/Kg body weight) of Pb dissolved in normal saline were given to mice by oral intubation in a sub-acute (28 days) and sub-chronic (90 days) regimen followed by SFV infection. Morbidity, mortality, clinical symptoms, mean survival time (MST), changes in body and organ weight, accumulation of lead in soft tissues, virus titre in brain and histopathological alterations were compared between lead exposed and infected groups.

RESULTSEarly appearance of virus symptoms, increased mortality, decreased MST, enhanced SFV titre and greater tissue damage were observed in lead exposed-SFV-infected mice.

CONCLUSIONPre-exposure to lead increases the susceptibility of mice towards SFV infection. Further studies are suggested in view of the persistence of lead in the environment and the possibility of infection by microbial pathogens.

Alphavirus Infections ; etiology ; veterinary ; Animals ; Brain ; pathology ; Dose-Response Relationship, Drug ; Kidney ; pathology ; Lead ; administration & dosage ; toxicity ; Liver ; pathology ; Mice ; Semliki forest virus ; pathogenicity

To construct vector system of XJ-160 virus, a Sindbis virus isolated in China, recombinant vector pBRepXJ together with its helper plasmid pBR-H were derived from XJ-160 viral infectious clone pBR-XJ160 by overlap-PCR. To quantitatively and qualitatively verify the function of the replicon system, recombinant plasmids pSinRep-EGFP, pBRepXJ-EGFP, pSinRep-R and pBRepXJ-R were constructed by cloning report genes of enhanced green fluorescent protein (EGFP) or Renilla luciferase (R. luc) into pBRepXJ or pSinRep5, a commercial Sindbis vector. And in Vitro-synthesized RNA from expression vectors were electroporated into BHK-21 cells. The results indicated that the replicon vector system was capable of self-replicating in host cell, and the expression efficiency of heterologous genes corresponded with that of the commercial Sindbis vector (pSinRep5). Our study laid the basis for developing alphavirus vector system with Chinese intellectual property.
Alphavirus Infections ; genetics ; Cloning, Molecular ; DNA, Complementary ; analysis ; genetics ; Genetic Vectors ; Genome, Viral ; Replicon ; genetics ; Sindbis Virus ; genetics ; Virus Replication ; physiology