Arboviruses: Arthropod-borne viruses. A non-taxonomic designation for viruses that can replicate in both vertebrate hosts and arthropod vectors. Included are some members of the following families: ARENAVIRIDAE; BUNYAVIRIDAE; REOVIRIDAE; TOGAVIRIDAE; and FLAVIVIRIDAE. (From Dictionary of Microbiology and Molecular Biology, 2nd ed)Arbovirus Infections: Infections caused by arthropod-borne viruses, general or unspecified.Encephalitis Viruses: A collection of single-stranded RNA viruses scattered across the Bunyaviridae, Flaviviridae, and Togaviridae families whose common property is the ability to induce encephalitic conditions in infected hosts.Culicidae: A family of the order DIPTERA that comprises the mosquitoes. The larval stages are aquatic, and the adults can be recognized by the characteristic WINGS, ANIMAL venation, the scales along the wing veins, and the long proboscis. Many species are of particular medical importance.Aedes: A genus of mosquitoes (CULICIDAE) frequently found in tropical and subtropical regions. YELLOW FEVER and DENGUE are two of the diseases that can be transmitted by species of this genus.Ceratopogonidae: A family of biting midges, in the order DIPTERA. It includes the genus Culicoides which transmits filarial parasites pathogenic to man and other primates.Insect Vectors: Insects that transmit infective organisms from one host to another or from an inanimate reservoir to an animate host.Culex: A genus of mosquitoes (CULICIDAE) commonly found in tropical regions. Species of this genus are vectors for ST. LOUIS ENCEPHALITIS as well as many other diseases of man and domestic and wild animals.Encephalitis Virus, St. Louis: A species of FLAVIVIRUS, one of the Japanese encephalitis virus group (ENCEPHALITIS VIRUSES, JAPANESE), which is the etiologic agent of ST. LOUIS ENCEPHALITIS in the United States, the Caribbean, and Central and South America.Alouatta: A genus of the subfamily ALOUATTINAE, family ATELIDAE, inhabiting the forests of Central and South America. Howlers travel in groups and define their territories by howling accompanied by vigorously shaking and breaking branches.Alphavirus: A genus of TOGAVIRIDAE, also known as Group A arboviruses, serologically related to each other but not to other Togaviridae. The viruses are transmitted by mosquitoes. The type species is the SINDBIS VIRUS.Chikungunya virus: A species of ALPHAVIRUS causing an acute dengue-like fever.Bunyaviridae Infections: Virus diseases caused by the BUNYAVIRIDAE.Encephalitis Virus, Western Equine: A species of ALPHAVIRUS that is the etiologic agent of encephalomyelitis in humans and equines in the United States, southern Canada, and parts of South America.Encephalitis, St. Louis: A viral encephalitis caused by the St. Louis encephalitis virus (ENCEPHALITIS VIRUS, ST. LOUIS), a FLAVIVIRUS. It is transmitted to humans and other vertebrates primarily by mosquitoes of the genus CULEX. The primary animal vectors are wild birds and the disorder is endemic to the midwestern and southeastern United States. Infections may be limited to an influenza-like illness or present as an ASEPTIC MENINGITIS or ENCEPHALITIS. Clinical manifestations of the encephalitic presentation may include SEIZURES, lethargy, MYOCLONUS, focal neurologic signs, COMA, and DEATH. (From Adams et al., Principles of Neurology, 6th ed, p750)Encephalitis Virus, Eastern Equine: A species of ALPHAVIRUS causing encephalomyelitis in Equidae and humans. The virus ranges along the Atlantic seaboard of the United States and Canada and as far south as the Caribbean, Mexico, and parts of Central and South America. Infections in horses show a mortality of up to 90 percent and in humans as high as 80 percent in epidemics.Bunyaviridae: A family of viruses, mainly arboviruses, consisting of a single strand of RNA. Virions are enveloped particles 90-120 nm diameter. The complete family contains over 300 members arranged in five genera: ORTHOBUNYAVIRUS; HANTAVIRUS; NAIROVIRUS; PHLEBOVIRUS; and TOSPOVIRUS.West Nile virus: A species of FLAVIVIRUS, one of the Japanese encephalitis virus group (ENCEPHALITIS VIRUSES, JAPANESE). It can infect birds and mammals. In humans, it is seen most frequently in Africa, Asia, and Europe presenting as a silent infection or undifferentiated fever (WEST NILE FEVER). The virus appeared in North America for the first time in 1999. It is transmitted mainly by CULEX spp mosquitoes which feed primarily on birds, but it can also be carried by the Asian Tiger mosquito, AEDES albopictus, which feeds mainly on mammals.Encephalitis Virus, California: A species in the ORTHOBUNYAVIRUS genus of the family BUNYAVIRIDAE. Serotypes are found in temperate and arctic regions and each is closely associated with a single species of vector mosquito. The vertebrate hosts are usually small mammals but several serotypes infect humans.Alphavirus Infections: Virus diseases caused by members of the ALPHAVIRUS genus of the family TOGAVIRIDAE.Arthropod Vectors: Arthropods, other than insects and arachnids, which transmit infective organisms from one host to another or from an inanimate reservoir to an animate host.Hemagglutination Inhibition Tests: Serologic tests in which a known quantity of antigen is added to the serum prior to the addition of a red cell suspension. Reaction result is expressed as the smallest amount of antigen which causes complete inhibition of hemagglutination.Disease Vectors: Invertebrates or non-human vertebrates which transmit infective organisms from one host to another.West Nile Fever: A mosquito-borne viral illness caused by the WEST NILE VIRUS, a FLAVIVIRUS and endemic to regions of Africa, Asia, and Europe. Common clinical features include HEADACHE; FEVER; maculopapular rash; gastrointestinal symptoms; and lymphadenopathy. MENINGITIS; ENCEPHALITIS; and MYELITIS may also occur. The disease may occasionally be fatal or leave survivors with residual neurologic deficits. (From Joynt, Clinical Neurology, 1996, Ch26, p13; Lancet 1998 Sep 5;352(9130):767-71)Encephalitis, Arbovirus: Infections of the brain caused by arthropod-borne viruses (i.e., arboviruses) primarily from the families TOGAVIRIDAE; FLAVIVIRIDAE; BUNYAVIRIDAE; REOVIRIDAE; and RHABDOVIRIDAE. Life cycles of these viruses are characterized by ZOONOSES, with birds and lower mammals serving as intermediate hosts. The virus is transmitted to humans by the bite of mosquitoes (CULICIDAE) or TICKS. Clinical manifestations include fever, headache, alterations of mentation, focal neurologic deficits, and COMA. (From Clin Microbiol Rev 1994 Jan;7(1):89-116; Walton, Brain's Diseases of the Nervous System, 10th ed, p321)Flavivirus: A genus of FLAVIVIRIDAE containing several subgroups and many species. Most are arboviruses transmitted by mosquitoes or ticks. The type species is YELLOW FEVER VIRUS.Encephalomyelitis, Eastern Equine: A form of arboviral encephalitis (primarily affecting equines) endemic to eastern regions of North America. The causative organism (ENCEPHALOMYELITIS VIRUS, EASTERN EQUINE) may be transmitted to humans via the bite of AEDES mosquitoes. Clinical manifestations include the acute onset of fever, HEADACHE, altered mentation, and SEIZURES followed by coma. The condition is fatal in up to 50% of cases. Recovery may be marked by residual neurologic deficits and EPILEPSY. (From Joynt, Clinical Neurology, 1996, Ch26, pp9-10)Orbivirus: A genus of REOVIRIDAE infecting a wide range of arthropods and vertebrates including humans. It comprises at least 21 serological subgroups. Transmission is by vectors such as midges, mosquitoes, sandflies, and ticks.Hemagglutination, Viral: Agglutination of ERYTHROCYTES by a virus.Encephalitis, California: A viral infection of the brain caused by serotypes of California encephalitis virus (ENCEPHALITIS VIRUS, CALIFORNIA) transmitted to humans by the mosquito AEDES triseriatus. The majority of cases are caused by the LA CROSSE VIRUS. This condition is endemic to the midwestern United States and primarily affects children between 5-10 years of age. Clinical manifestations include FEVER; VOMITING; HEADACHE; and abdominal pain followed by SEIZURES, altered mentation, and focal neurologic deficits. (From Joynt, Clinical Neurology, 1996, Ch26, p13)Orthobunyavirus: A genus of the family BUNYAVIRIDAE containing over 150 viruses, most of which are transmitted by mosquitoes or flies. They are arranged in groups defined by serological criteria, each now named for the original reference species (previously called serogroups). Many species have multiple serotypes or strains.Phlebovirus: A genus of the family BUNYAVIRIDAE comprising many viruses, most of which are transmitted by Phlebotomus flies and cause PHLEBOTOMUS FEVER. The type species is RIFT VALLEY FEVER VIRUS.Simbu virus: A species in the ORTHOBUNYAVIRUS genus of the family BUNYAVIRIDAE family. Previously a large group of serotypes, most are now considered separate species.Dengue Virus: A species of the genus FLAVIVIRUS which causes an acute febrile and sometimes hemorrhagic disease in man. Dengue is mosquito-borne and four serotypes are known.La Crosse virus: A serotype of the species California encephalitis virus (ENCEPHALITIS VIRUS, CALIFORNIA), in the genus ORTHOBUNYAVIRUS, causing human MENINGOENCEPHALITIS. This is the agent most responsible for California encephalitis (ENCEPHALITIS, CALIFORNIA), the most prevalent mosquito-borne disease recognized in the United States.Ticks: Blood-sucking acarid parasites of the order Ixodida comprising two families: the softbacked ticks (ARGASIDAE) and hardbacked ticks (IXODIDAE). Ticks are larger than their relatives, the MITES. They penetrate the skin of their host by means of highly specialized, hooked mouth parts and feed on its blood. Ticks attack all groups of terrestrial vertebrates. In humans they are responsible for many TICK-BORNE DISEASES, including the transmission of ROCKY MOUNTAIN SPOTTED FEVER; TULAREMIA; BABESIOSIS; AFRICAN SWINE FEVER; and RELAPSING FEVER. (From Barnes, Invertebrate Zoology, 5th ed, pp543-44)Yellow Fever: An acute infectious disease primarily of the tropics, caused by a virus and transmitted to man by mosquitoes of the genera Aedes and Haemagogus. The severe form is characterized by fever, HEMOLYTIC JAUNDICE, and renal damage.Sindbis Virus: The type species of ALPHAVIRUS normally transmitted to birds by CULEX mosquitoes in Egypt, South Africa, India, Malaya, the Philippines, and Australia. It may be associated with fever in humans. Serotypes (differing by less than 17% in nucleotide sequence) include Babanki, Kyzylagach, and Ockelbo viruses.Bird Diseases: Diseases of birds not considered poultry, therefore usually found in zoos, parks, and the wild. The concept is differentiated from POULTRY DISEASES which is for birds raised as a source of meat or eggs for human consumption, and usually found in barnyards, hatcheries, etc.Encephalitis Virus, Venezuelan Equine: A species of ALPHAVIRUS that is the etiologic agent of encephalomyelitis in humans and equines. It is seen most commonly in parts of Central and South America.Complement Fixation Tests: Serologic tests based on inactivation of complement by the antigen-antibody complex (stage 1). Binding of free complement can be visualized by addition of a second antigen-antibody system such as red cells and appropriate red cell antibody (hemolysin) requiring complement for its completion (stage 2). Failure of the red cells to lyse indicates that a specific antigen-antibody reaction has taken place in stage 1. If red cells lyse, free complement is present indicating no antigen-antibody reaction occurred in stage 1.Rift Valley Fever: An acute infection caused by the RIFT VALLEY FEVER VIRUS, an RNA arthropod-borne virus, affecting domestic animals and humans. In animals, symptoms include HEPATITIS; abortion (ABORTION, VETERINARY); and DEATH. In humans, symptoms range from those of a flu-like disease to hemorrhagic fever, ENCEPHALITIS, or BLINDNESS.Encephalitis Virus, Japanese: A species of FLAVIVIRUS, one of the Japanese encephalitis virus group (ENCEPHALITIS VIRUSES, JAPANESE), which is the etiological agent of Japanese encephalitis found in Asia, southeast Asia, and the Indian subcontinent.Antibodies, Viral: Immunoglobulins produced in response to VIRAL ANTIGENS.Neutralization Tests: The measurement of infection-blocking titer of ANTISERA by testing a series of dilutions for a given virus-antiserum interaction end-point, which is generally the dilution at which tissue cultures inoculated with the serum-virus mixtures demonstrate cytopathology (CPE) or the dilution at which 50% of test animals injected with serum-virus mixtures show infectivity (ID50) or die (LD50).Yellow fever virus: The type species of the FLAVIVIRUS genus. Principal vector transmission to humans is by AEDES spp. mosquitoes.Zoonoses: Diseases of non-human animals that may be transmitted to HUMANS or may be transmitted from humans to non-human animals.Encephalomyelitis, Equine: A group of ALPHAVIRUS INFECTIONS which affect horses and man, transmitted via the bites of mosquitoes. Disorders in this category are endemic to regions of South America and North America. In humans, clinical manifestations vary with the type of infection, and range from a mild influenza-like syndrome to a fulminant encephalitis. (From Joynt, Clinical Neurology, 1996, Ch26, pp8-10)Encephalitis Viruses, Tick-Borne: A subgroup of the genus FLAVIVIRUS that causes encephalitis and hemorrhagic fevers and is found in eastern and western Europe and the former Soviet Union. It is transmitted by TICKS and there is an associated milk-borne transmission from viremic cattle, goats, and sheep.Communicable Diseases, Emerging: Infectious diseases that are novel in their outbreak ranges (geographic and host) or transmission mode.Semliki forest virus: A species of ALPHAVIRUS isolated in central, eastern, and southern Africa.Birds: Warm-blooded VERTEBRATES possessing FEATHERS and belonging to the class Aves.