RESUMEN
The co-circulation of all 4 dengue virus serotypes in the same community, common since the 1950s in Southeast Asia, has now become a frequent occurrence in many Caribbean Islands, Mexico, and Central and South America in the past 20 years. As a consequence, the frequency of concurrent infections would be expected to increase in these areas. To assess this, using state of the art technology, we screened viremic serum samples and mosquitoes inoculated with serum samples collected during epidemics involving multiple dengue virus serotypes in Indonesia, Mexico, and Puerto Rico for virus isolation. Of 292 samples tested, 16 (5.5%) were found to contain 2 or more dengue viruses by an indirect immunofluorescence test and/or the reverse transcriptase-polymerase chain reaction.
Asunto(s)
Virus del Dengue/clasificación , Brotes de Enfermedades , Dengue Grave/virología , Animales , Anticuerpos Monoclonales , Anticuerpos Antivirales/sangre , Bioensayo , Células Cultivadas , Culicidae/virología , Cartilla de ADN/química , Virus del Dengue/genética , Virus del Dengue/inmunología , Virus del Dengue/patogenicidad , Electroforesis en Gel de Agar , Técnica del Anticuerpo Fluorescente Directa , Humanos , Indonesia/epidemiología , México/epidemiología , Puerto Rico/epidemiología , ARN Viral/química , ARN Viral/aislamiento & purificación , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Serotipificación , Dengue Grave/sangre , Dengue Grave/epidemiologíaRESUMEN
A survey was conducted from October 1, 1993 to June 30, 1995 to determine the arboviral etiologies of febrile illnesses in the city of Iquitos in the Amazon River Basin of Peru. The study subjects were patients who were enrolled at medical care clinics or in their homes by Peruvian Ministry of Health (MOH) workers as part of the passive and active disease surveillance program of the MOH. The clinical criterion for enrollment was the diagnosis of a suspected viral-associated, acute, undifferentiated febrile illness of < or = 5 days duration. A total of 598 patients were enrolled in the study. Demographic information, medical history, clinical data, and blood samples were obtained from each patient. The more common clinical features were fever, headache, myalgia, arthralgia, retro-ocular pain, and chills. Sera were tested for virus by the newborn mouse and cell culture assays. Viral isolates were identified initially by immunofluorescence using polyclonal antibody. An ELISA using viral-specific monoclonal antibodies and nucleotide sequence analysis were used to determine the specific variety of the viruses. In addition, thin and thick blood smears were observed for malaria parasites. Venezuelan equine encephalitis (VEE) virus subtype I, variety ID virus was isolated from 10 cases, including three cases in October, November, and December 1993, five cases in January and February 1994, and two cases in June 1995. The ELISA for IgM and IgG antibody indicated that VEE virus was the cause of an additional four confirmed and four presumptive cases, including five from January through March 1994 and three in August 1994. Sixteen cases were positive for malaria. The 18 cases of VEE occurred among military recruits (n = 7), agriculture workers (n = 3), students (n = 3), and general laborers (n = 5). These data indicated that an enzootic strain of VEE virus was the cause of at least 3% (18 of 598) of the cases of febrile illnesses studied in the city of Iquitos in the Amazon Basin region of Peru.
Asunto(s)
Encefalomielitis Equina Venezolana/diagnóstico , Encefalomielitis Equina Venezolana/epidemiología , Adolescente , Adulto , Anciano , Instituciones de Atención Ambulatoria , Anticuerpos Antivirales/análisis , Células Cultivadas , Niño , Preescolar , Virus de la Encefalitis Equina Venezolana/clasificación , Virus de la Encefalitis Equina Venezolana/genética , Virus de la Encefalitis Equina Venezolana/inmunología , Encefalomielitis Equina Venezolana/sangre , Ensayo de Inmunoadsorción Enzimática , Mapeo Epitopo , Femenino , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Lactante , Malaria/diagnóstico , Masculino , Persona de Mediana Edad , Epidemiología Molecular , Perú/epidemiología , Filogenia , Reacción en Cadena de la Polimerasa , Vigilancia de la Población , ARN Viral/análisis , ARN Viral/genética , Estudios Seroepidemiológicos , SerotipificaciónRESUMEN
An outbreak of a febrile illness characterized by headache, ocular pain, myalgia, and arthralgia occurred during June 1994 among Peruvian army troops in Northern Peru. On June 14-16, 1994, clinical data and blood samples were obtained from eight soldiers with a febrile illness, and from 26 others who had a history of febrile illness during the past three months. A follow-up blood sample was obtained 107 days later from four of the febrile and seven of the afebrile soldiers. Serum samples were tested for dengue (DEN), Oropouche (ORO), and Venezuelan equine encephalitis (VEE) IgM and IgG antibodies by an enzyme-linked immunosorbent assay (ELISA). Virus isolation was performed by inoculation of newborn mice and Vero cell cultures. Viral isolates were identified by immunofluorescence, ELISA, and nucleotide sequencing. A VEE virus infection was confirmed in three of the eight febrile soldiers, two by virus isolation, and one by serology. Antigenic analysis indicated that one of the virus isolates was similar to VEE subtype I, variety ID, viruses previously isolated in Colombia and Venezuela. Nucleotide sequence data showed that both viral isolates were identical to one another and closely related to VEE ID viruses previously isolated in Peru, Colombia, and Venezuela. Serologic results showed that two of 26 afebrile soldiers had IgM antibody to VEE and four had IgG antibody to VEE; two febrile soldiers had IgG antibody in their first serum samples. Oropouche-specific IgM antibody was detected in one of the eight febrile and five of the afebrile soldiers, and 18 of the 34 soldiers had low titers of ORO IgG antibody titers, which did not meet the diagnostic criteria for confirmed cases. All soldiers were negative for DEN IgM antibody, and 10 had flavivirus IgG antibody that reacted with DEN antigens. These data indicated that VEE ID virus was one of the causes of illness among Peruvians soldiers and that this was the first association of this VEE subtype with human disease in Peru.
Asunto(s)
Infecciones por Bunyaviridae/epidemiología , Brotes de Enfermedades , Encefalomielitis Equina Venezolana/epidemiología , Adolescente , Adulto , Animales , Anticuerpos Antivirales/sangre , Infecciones por Bunyaviridae/virología , Virus de la Encefalitis Equina Venezolana/inmunología , Virus de la Encefalitis Equina Venezolana/aislamiento & purificación , Encefalomielitis Equina Venezolana/virología , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Masculino , Ratones , Orthobunyavirus , Perú/epidemiología , Estudios Seroepidemiológicos , Virus Simbu/inmunología , Virus Simbu/aislamiento & purificaciónRESUMEN
In 1981, a localized epizootic of Eastern Equine Encephalitis (EEE) occurred in irrigated areas of four counties in the province of Santiago del Estero, Argentina. The diagnosis was confirmed by serology, and there was no evidence of involvement of Western or Venezuelan equine encephalitis viruses. The overall incidence of equine encephalitis was estimated 17%, the case-fatality rate at 61% and the inapparent: apparent infection ratio less than or equal to 2.9:1. This is the first localized epizootic defined in Argentina and the first in which EEE has been found as the sole etiologic arbovirus. This posed the possibility to look for human infection in the area. In spite of a careful surveillance, no evidence of human disease or infection was found, differing from the situation in USA where EEE virus is a public health problem. Nevertheless vector/s and vertebrate hosts involved in the transmission cycle in Argentina remain unknown, precluding at present speculations on the potential human risk.
Asunto(s)
Brotes de Enfermedades/veterinaria , Virus de la Encefalitis Equina del Este , Encefalomielitis Equina/epidemiología , Enfermedades de los Caballos/epidemiología , Animales , Argentina/epidemiología , Encefalomielitis Equina/diagnóstico , Encefalomielitis Equina/etiología , Caballos , Pruebas SerológicasRESUMEN
Se documenta una epizootia de encefalitis equina del este (EEE) localizada en una zona irrigada de cuatro departamentos de la Privincia de Santiago del Estero, Argentina, en 1981. La incidencia de casos equinos fue estimada en 17% con una tasa de casos fatales del 61% y una relación de infección inaparente: aparente de < ou = 2,9:1. El diagnóstico para el virus EEE fue confirmado por pruebas serológicas y no se encontró evidencia de casos por virus de las encefalitis del oeste o Venezuela. Esta es la primera epizootia circunscripta a una pequeña área geográfica que se ha definido en Argentina y la primera en que el virus EEE se ha encontrado como único arbovirus etiológico. Su reconocimiento brindo la posibilidad de buscar la infección humana, pero no se encontró clara evidencia de enfermedad o infección. Esto se atribuyó a la baja densidad de población humana rural, aunque no se descartaron otros factores ecológicos. La serología en otros animales no permitió determinar los huéspedes vertebrados y no se estudiaron los vectores por lo cual el ciclo de transmisión continúa desconocido, impidiendo especular sobre el riesgo potencial del virus EEE para el hombre en Argentina (AU)
Asunto(s)
Animales , Encefalomielitis Equina/epidemiología , Enfermedades de los Caballos/epidemiología , Virus de la Encefalitis Equina del Este , Caballos , Argentina/epidemiología , Encefalomielitis Equina/etiología , Encefalomielitis Equina/diagnóstico , Pruebas SerológicasRESUMEN
In 1981, a localized epizootic of Eastern Equine Encephalitis (EEE) occurred in irrigated areas of four counties in the province of Santiago del Estero, Argentina. The diagnosis was confirmed by serology, and there was no evidence of involvement of Western or Venezuelan equine encephalitis viruses. The overall incidence of equine encephalitis was estimated 17
, the case-fatality rate at 61
and the inapparent: apparent infection ratio less than or equal to 2.9:1. This is the first localized epizootic defined in Argentina and the first in which EEE has been found as the sole etiologic arbovirus. This posed the possibility to look for human infection in the area. In spite of a careful surveillance, no evidence of human disease or infection was found, differing from the situation in USA where EEE virus is a public health problem. Nevertheless vector/s and vertebrate hosts involved in the transmission cycle in Argentina remain unknown, precluding at present speculations on the potential human risk.
RESUMEN
Se documenta una epizootia de encefalitis equina del este (EEE) localizada en una zona irrigada de cuatro departamentos de la Privincia de Santiago del Estero, Argentina, en 1981. La incidencia de casos equinos fue estimada en 17% con una tasa de casos fatales del 61% y una relación de infección inaparente: aparente de < ou = 2,9:1. El diagnóstico para el virus EEE fue confirmado por pruebas serológicas y no se encontró evidencia de casos por virus de las encefalitis del oeste o Venezuela. Esta es la primera epizootia circunscripta a una pequeña área geográfica que se ha definido en Argentina y la primera en que el virus EEE se ha encontrado como único arbovirus etiológico. Su reconocimiento brindo la posibilidad de buscar la infección humana, pero no se encontró clara evidencia de enfermedad o infección. Esto se atribuyó a la baja densidad de población humana rural, aunque no se descartaron otros factores ecológicos. La serología en otros animales no permitió determinar los huéspedes vertebrados y no se estudiaron los vectores por lo cual el ciclo de transmisión continúa desconocido, impidiendo especular sobre el riesgo potencial del virus EEE para el hombre en Argentina
Asunto(s)
Animales , Enfermedades de los Caballos/epidemiología , Virus de la Encefalitis Equina del Este , Encefalomielitis Equina/epidemiología , Argentina/epidemiología , Encefalomielitis Equina/diagnóstico , Encefalomielitis Equina/etiología , Caballos , Pruebas SerológicasRESUMEN
Mosquitoes were collected in Santa Fe and Rio Negro provinces, Argentina, in 1982-1983 during a western equine encephalitis (WEE) epizootic. Totals of 153,084 mosquitoes from Santa Fe Province and 484 from Rio Negro Province were tested for virus in 2,351 pools. Seventeen virus strains were isolated, all from Santa Fe collections, as follows: 4 WEE, 6 Venezuelan equine encephalitis, 1 St. Louis encephalitis, 2 Antequera, 1 Maguari, 1 Melao, 1 new vesiculovirus (Calchaqui), and 1 Gamboa. The WEE virus isolates were from Aedes albifasciatus, Anopheles albitarsis, Mansonia species, and Psorophora pallescens. Collections during the spring and summer (1983-1984) following the epizootic yielded 49,707 mosquitoes from Santa Fe, 15,961 from Rio Negro, and 2,019 from Chubut provinces. Twenty-two virus strains were isolated, all from Santa Fe mosquitoes, as follows: 3 strains of SLE virus and 19 strains of Turlock (TUR) virus. All but one of the TUR virus isolates appear to have come from mosquitoes that engorged on a viremic chicken following entry into a bait trap. The vector relationships of each virus isolated during and after the WEE epizootic are discussed.
Asunto(s)
Arbovirus/aislamiento & purificación , Culicidae/microbiología , Encefalomielitis Equina/transmisión , Aedes/microbiología , Animales , Anopheles/microbiología , Argentina , Virus de la Encefalitis de San Luis/aislamiento & purificación , Virus de la Encefalitis Equina Venezolana/aislamiento & purificación , Virus de la Encefalitis Equina del Oeste/aislamiento & purificación , Insectos Vectores/microbiologíaRESUMEN
In 1983, 17 virus strains were isolated from mosquitoes collected during an outbreak of western equine encephalitis in Santa Fe Province, Argentina. Strains of western equine encephalitis, Venezuelan equine encephalitis, St. Louis encephalitis, and Antequera viruses were isolated, as were several bunyaviruses of the California and Bunyamwera serogroups and a new vesiculovirus. Complement fixation and neutralization tests were used to identify the California serogroup virus as a subtype of Melao virus, the Bunyamwera serogroup virus as a subtype of both Maguari and Playas viruses, and the vesiculovirus as a newly recognized agent for which the name Calchaqui virus is proposed. A limited serosurvey of horses and humans in Santa Fe Province and horses from the adjacent Santiago del Estero Province was performed to determine the prevalence of neutralizing antibody to the subtypes of Melao and Maguari viruses and to Calchaqui virus. The high prevalence of antibodies to these three agents indicates the need for further studies of their disease potential in horses, because they are closely related to several other viruses that are known equine pathogens.
Asunto(s)
Virus Bunyamwera/aislamiento & purificación , Bunyaviridae/aislamiento & purificación , Virus de la Encefalitis de California/aislamiento & purificación , Encefalomielitis Equina/microbiología , Enfermedades de los Caballos/microbiología , Virus de la Estomatitis Vesicular Indiana/aislamiento & purificación , Animales , Argentina , Pruebas de Fijación del Complemento , Culex/microbiología , Culicidae/microbiología , Encefalomielitis Equina/veterinaria , Femenino , Técnica del Anticuerpo Fluorescente , Caballos/microbiología , Humanos , Pruebas de Neutralización , Células Vero/microbiología , Ensayo de Placa ViralRESUMEN
Prospective surveys for arboviruses were carried out in Santa Fe, Corrientes, and Chaco provinces, Argentina, aperiodically during 1977-1980. A total of 313,233 mosquitoes and 598 biting flies other than mosquitoes were collected and tested for virus in 5,197 and 45 pools, respectively. Forty virus strains were isolated, all from mosquitoes, as follows: Santa Fe Province: 4 Gamboa group viruses from Aedeomyia squamipennis, 1 strain each of St. Louis encephalitis virus from Culex pipiens quinquefasciatus and Culex (Culex) spp.; Corrientes Province: a single strain of a newly discovered Anopheles A serogroup virus, Las Maloyas, from Anopheles albitarsis; and Chaco Province: 4 Gamboa group viruses from Ad. squamipennis, 6 strains of new Bunyaviridae (1 Antequera, 1 Barranqueras, and 4 Resistencia) from Culex (Melanoconion) delpontei, 3 strains of a new subtype of western equine encephalitis virus and 1 strain of Para virus from the Cx. (Mel.) ocossa group, 12 strains of a newly discovered subtype (VI) of the Venezuelan equine encephalitis complex from Cx. (Mel.) delpontei, and 1 strain each from Ad. squamipennis, Aedes scapularis, Ae. spp., Cx. (Cux.) spp., Cx. (Mel.) ocossa group, Mansonia spp., and Psorophora spp. Bloodmeals from 265 engorged mosquitoes were identified by precipitin test. These data, coupled with data on engorgement rates for 25,995 mosquitoes from bait collections, provide information on the host feeding patterns of several mosquito species. This information is discussed, along with data on relative abundance of mosquito species, within the context of the vector relationships of the species from which viruses were isolated. The association of Cx. (Mel.) delpontei with 18 strains of 4 different viruses in Chaco Province, plus its catholic feeding habits, clearly indicate for the first time the importance of this species as an arbovirus vector.
Asunto(s)
Arbovirus/aislamiento & purificación , Artrópodos/microbiología , Culicidae/microbiología , Aedes/microbiología , Animales , Anopheles/microbiología , Argentina , Aves/microbiología , Sangre/microbiología , Bunyaviridae/aislamiento & purificación , Pollos/inmunología , Cricetinae , Culex/microbiología , Virus de la Encefalitis Equina Venezolana/aislamiento & purificación , Virus de la Encefalitis Equina del Oeste/aislamiento & purificación , Femenino , Sueros Inmunes/inmunología , Masculino , Ratones , Conejos/inmunologíaRESUMEN
Forty viruses isolated from mosquitoes between 1977 and 1980 in Argentina have been identified and characterized. Nineteen strains of VEE virus, identical by neutralization (N) tests, were shown by hemagglutination-inhibition tests with anti-E2 glycoprotein sera to represent a new subtype VI of the VEE complex. RNA oligonucleotide fingerprints of this virus were distinct from subtype I viruses. The virus was not lethal for English short-haired guinea pigs, indicating that it is probably not equine-virulent. Three strains of a member of the WEE virus complex were shown to differ by N tests in 1 direction from prototype WEE virus. The new WEE subtype was also found to be distinct by RNA oligonucleotide mapping. Its vector relationships indicate that it is an enzootic virus, and it has not been associated with equine disease. A new member of the Anopheles A serogroup was identified, shown to be most closely related to Lukuni and Col An 57389 viruses, and given the name Las Maloyas virus. A strain of Para virus (Bunyaviridae, Bunyavirus) was identified. Six isolates, representing 3 new viruses morphologically resembling bunyaviruses are described; the names Antequera, Barranqueras, and Resistencia are proposed for these agents, which were all isolated from Culex (Melanoconion) delpontei in Chaco Province. No serologic relationships between these viruses and other bunyaviruses were found. Since they are antigenically interrelated, they form a new (Antequera) serogroup. Eight Gamboa serogroup viruses and 2 strains of St. Louis encephalitis virus were also identified.
Asunto(s)
Arbovirus/aislamiento & purificación , Bunyaviridae/aislamiento & purificación , Virus de la Encefalitis Equina Venezolana/aislamiento & purificación , Virus de la Encefalitis Equina del Oeste/aislamiento & purificación , Aedes/microbiología , Alphavirus/inmunología , Animales , Anopheles/microbiología , Arbovirus/genética , Argentina , Bunyaviridae/genética , Pruebas de Fijación del Complemento , Cricetinae , Culex/microbiología , Culicidae/microbiología , Patos , Virus de la Encefalitis Equina Venezolana/genética , Virus de la Encefalitis Equina del Oeste/genética , Cobayas , Pruebas de Inhibición de Hemaglutinación , Sueros Inmunes/inmunología , Insectos Vectores/microbiología , Ratones/inmunología , Pruebas de Neutralización , ARN Viral/aislamiento & purificación , Conejos/inmunología , Ensayo de Placa ViralRESUMEN
Serologic surveys of wild and domestic birds, wild mammals, and horses were conducted during arbovirus field studies in Argentina from 1977 through 1980, a non-epizootic interval. The prevalence of neutralizing antibodies to eastern equine encephalitis (EEE) was consistently higher than to western equine encephalitis (WEE) virus in all species and all areas. The presence of antibodies in short-lived avian species and in young unvaccinated horses and the demonstration of seroconversions in horses during the period, indicated that these viruses are either enzootic in, or annually reintroduced into, Argentina. Antibodies to AG80-646, a new subtype of WEE virus isolated in the subtropical north (Chaco Province) from Culex (Melanoconion) mosquitoes, were found in horses and rodents in that region. Antibodies to the TC-83 strain of Venezuelan equine encephalitis (VEE) virus were found in all areas studied. The presence of antibodies in some horses was probably related to vaccination, but the demonstration of seroconversions in sentinel horses and of antibodies in birds and wild mammals indicates active transmission of VEE virus. In 1980 a new enzootic subtype of VEE virus (AG80-663) was isolated from mosquitoes in Chaco; neutralizing antibodies to this virus were prevalent in horses and rodents in this area. Infections with Aura and Una viruses were most common in the subtropical northern provinces. Infection with St. Louis encephalitis was prevalent and widespread, and birds, principally passerine and columbiform species, appear to be the principal hosts. An interesting and unexplained finding was the absence of arbovirus antibodies, in particular SLE antibodies in house sparrows (Passer domesticus). Antibody prevalences in horses exceeded 50% in all areas, and 12% of horses surveyed in Santa Fe Province developed antibody in a 17-month period. Antibodies to other flaviviruses were rare. A high prevalence of immunity to Maguari virus was found in horses; this agent is considered to be a potential equine pathogen. Antibodies to 2 new viruses, Barranqueras and Resistencia, which had been isolated from Cx. (Melanoconion) in Chaco Province, were found in rodents there. Immunity to Gamboa group viruses was prevalent, and birds were implicated as principal hosts.
Asunto(s)
Arbovirus/fisiología , Alphavirus/inmunología , Animales , Animales Salvajes/microbiología , Anticuerpos Antivirales/inmunología , Infecciones por Arbovirus/inmunología , Infecciones por Arbovirus/microbiología , Infecciones por Arbovirus/veterinaria , Arbovirus/inmunología , Argentina , Aves/microbiología , Bunyaviridae/inmunología , Culex/microbiología , Culicidae/microbiología , Virus de la Encefalitis de San Luis/inmunología , Virus de la Encefalitis Equina Venezolana/inmunología , Virus de la Encefalitis Equina del Oeste/inmunología , Encefalitis de San Luis/veterinaria , Encefalomielitis Equina/veterinaria , Encefalomielitis Equina Venezolana/veterinaria , Flavivirus/inmunología , Cobayas/microbiología , Enfermedades de los Caballos/microbiología , Caballos/microbiología , Insectos Vectores/microbiología , Pruebas de Neutralización , Roedores/microbiología , Vacunación/veterinariaRESUMEN
From 1975 to 1978, 36 viruses were recovered from humans, bats, birds, sentinel mice and hamsters, and from mosquitoes collected in Coastal Brazil in the state of São Paulo. Identifications of 22 of these 36 viruses have been reported. Six of the remaining 14 isolates were shown to be Guama serogroup bunyaviruses. Two of these six were strains of a newly recognized virus for which the name Cananeia virus is proposed; another is a second newly recognized Guama serogroup virus for which the name Itimirim virus is proposed; a fourth is a strain of Bertioga virus and the other two are strains of Guaratuba virus. Before these studies Guaratuba virus was considered an ungrouped bunyavirus, but cross testing by complement-fixation demonstrated that this virus, and Mirim virus as well, should be considered members of the Guama serogroup. Another six viruses were shown to be strains of a single, newly recognized Group C bunyavirus for which the name Bruconha virus is proposed. Two strains of a single virus were shown by electron microscopy to belong to the family Bunyaviridae, but serologic relationships with other members of this family of viruses were not found; the name Enseada virus is proposed for this newly recognized agent.
Asunto(s)
Bunyaviridae/aislamiento & purificación , Orthobunyavirus/aislamiento & purificación , Animales , Brasil , Cebus/microbiología , Pruebas de Fijación del Complemento , Cricetinae , Culex/microbiología , Humanos , Ratones , Muridae/microbiología , SerotipificaciónRESUMEN
A second virus with distinct biological, serological, and physiochemical properties was detected as a minority viral subpopulation in specimens of Cliff Swallow nest bugs (Oeciacus vicarius) and nestling bird sera containing Fort Morgan (FM) virus. The second virus, detected by a breakthrough neutralization test employing FM antiserum, was present in 5 of 11 FM virus-positive pools of nest bugs and in 4 of 38 birds from Colorado and South Dakota. The concentration of the second virus was 10-fold to 1,000-fold lower than that of FM virus. The second virus, which was provisionally named "Bijou Bridge" (BB) virus was shown by conventional serological tests to be a member of the Venezuelan equine encephalomyelitis (VEE) complex, and by tests employing antisera to the E2 viral glycoprotein to be identical with Tonate virus, previously isolated from birds and mosquitoes only in French Guiana. Experimental infection of House Sparrows and Cliff Swallows showed that they develop brief BB viremias and antibodies. Oe. vicarius bugs were resistant to oral infection with BB virus. The epidemiological significance of recovery of Tonate virus in North American is discussed.