Prevalence of attibodies against influenza viru in non-vaccinated equines fromm the Brazilian pantaall / Prevalência de anticorpos contra o vírus da Influenza em equinos não vacinados do Pantanal Brasileiro

The prevalence of antibodies against Equine Influenza Virus (EIV) was determined in 529 equines living on ranches in the municipality of Poconé, Pantanal area of Brazil, by means of the hemagglutination inhibition test, using subtype H3N8 as antigen. The distribution and possible association among positive animal and ranches were evaluated by the chi-square test, spatial autoregressive and multiple linear regression models. The prevalence of antibodies against EIV was estimated at 45.2% (95% CI 30.2 - 61.1%) with titers ranging from 20 to 1,280 HAU. Seropositive equines were found on 92.0% of the surveyed ranches. Equine from non-flooded ranches (66.5%) and negativity in equine infectious anemia virus (EIAV) (61.7%) were associated with antibodies against EIV. No spatial correlation was found among the ranches, but the ones located in non-flooded areas were associated with antibodies against EIV. A negative correlation was found between the prevalence of antibodies against EIV and the presence of EIAV positive animals on the ranches. The high prevalence of antibodies against EIV detected in this study suggests that the virus is circulating among the animals, and this statistical analysis indicates that the movement and aggregation of animals are factors associated to the transmission of the virus in the region.

A prevalência de anticorpos para o vírus da Influenza Equina (VIE) no município de Poconé, MT. foi determinada em 529 equídeos pela técnica de Inibição da hemaglutinação utilizando como antígeno a variante H3N8 (SP/1/85). A distribuição da positividade e possíveis associações entre os animais e as propriedades foram avaliadas pelo teste do Qui-quadrado e pelos modelos espacial autoregressivo misto e de regressão linear múltipla. A prevalência de anticorpos para o VIE no município de Poconé foi estimada em 45,2% (IC 95% 30,2 - 61,1%) com títulos variando entre 20 e 1280UIH. Das fazendas analisadas 23 (92,0%) apresentaram animais soropositivos. Animais de fazendas não alagadas (66,5%) e negativos para Anemia Infecciosa Equina (AIE) (61,7%) foram associados a soropositividade. Não houve correlação espacial entre as fazendas estudadas, entretanto aquelas localizadas nas áreas não alagadas foram associadas à infecção. Observou-se correlação negativa entre a prevalência de anticorpos para o VIE e a presença de animais positivos para AIE nas propriedades. A elevada prevalência de anticorpos para o VIE detectada neste estudo sugere circulação viral ativa entre os animais, e as análises estatísticas indicam que o trânsito e aglomeração animal são fatores associados à transmissão do vírus na região.

Serological evidence for Saint Louis encephalitis virus in free-ranging New World monkeys and horses within the upper Paraná River basin region, Southern Brazil

Introduction Saint Louis encephalitis virus (SLEV) primarily occurs in the Americas and produces disease predominantly in humans. This study investigated the serological presence of SLEV in nonhuman primates and horses from southern Brazil. Methods From June 2004 to December 2005, sera from 133 monkeys (Alouatta caraya, n=43; Sapajus nigritus, n=64; Sapajus cay, n=26) trap-captured at the Paraná River basin region and 23 blood samples from farm horses were obtained and used for the serological detection of a panel of 19 arboviruses. All samples were analyzed in a hemagglutination inhibition (HI) assay; positive monkey samples were confirmed in a mouse neutralization test (MNT). Additionally, all blood samples were inoculated into C6/36 cell culture for viral isolation. Results Positive seroreactivity was only observed for SLEV. A prevalence of SLEV antibodies in sera was detected in Alouatta caraya (11.6%; 5/43), Sapajus nigritus (12.5%; 8/64), and S. cay (30.8%; 8/26) monkeys with the HI assay. Of the monkeys, 2.3% (1/42) of A. caraya, 6.3% 94/64) of S. nigritus, and 15.4% (4/26) of S. cay were positive for SLEV in the MNT. Additionally, SLEV antibodies were detected by HI in 39.1% (9/23) of the horses evaluated in this study. Arboviruses were not isolated from any blood sample. Conclusions These results confirmed the presence of SLEV in nonhuman primates and horses from southern Brazil. These findings most likely represent the first detection of this virus in nonhuman primates beyond the Amazon region. The detection of SLEV in animals within a geographical region distant from the Amazon basin suggests that there may be widespread and undiagnosed dissemination of this disease in Brazil. .

Levantamento soroepidemiológico para arbovírus em macaco-prego-galego (Cebus flavius) de vida livre no estado da Paraíba e em macaco-prego (Cebus libidinosus) de cativeiro do nordeste do Brasil / Epidemiologic survey for arbovirus in galician capuchin monkeys (Cebus flavius) free living in Paraíba and captive capuchin monkey (Cebus libidinosus) from northeast Brazil

Este estudo descreve a primeira investigação de anticorpos para arbovírus em primatas não humanos do Novo Mundo no nordeste brasileiro. No período de março de 2008 a setembro de 2010 foram colhidos soros sanguíneos de 31 macacos-prego-galegos (Cebus flavius) de vida livre na Paraíba e de 100 macacos-prego (Cebus libidinosus) em cativeiro nos estados de Alagoas, Paraíba, Pernambuco, Piauí e Rio Grande do Norte. Para a pesquisa de anticorpos utilizou-se o teste de inibição da hemaglutinação (IH), usando antígenos de 19 diferentes tipos de arbovírus, pertencentes aos gêneros Flavivirus,Alphavirus e Bunyavirus. As amostras de soro foram testadas nas diluições de 1:20 a 1:1280. Dentre as amostras examinadas, todas as de C. flavius foram negativas e 46 por cento das de C. libidinosus em cativeiro apresentaram anticorpos para arbovírus. Foram detectados anticorpos para nove (9/19) arbovírus. Foram observadas 17 reações heterotípicas, para dois ou mais vírus, do gênero Flavivirus, e 15 para o gênero Alphavirus, com títulos variando de 1:20 a 1:1280. Quinze amostras apresentaram reação monotípica para ILHV (n=4), MAYV (n=6), SLEV (n=1), ROCV (n=2), OROV (n=1) e MUCV (n=1). Estes resultados sugerem que houve intensa circulação de arbovírus na população estudada de macacos-prego em cativeiro.

This paper describes the first investigation of arbovirus antibodies on New World non-human primates from Northeast Brazil. From March 2008 to September 2010 blood serum samples were collected from 31 wild blond capuchin monkeys (Cebus flavius) from Paraíba and 100 captive capuchin monkeys from Alagoas, Paraíba, Pernambuco, Piauí and Rio Grande do Norte. The haemagglutination-inhibition test (HI) was employed for 19 arbovirus of the Flavivirus,Alphavirus and Bunyavirus genus. Serum samples were tested from 1:20 to 1:1280 dilutions. Among the primates tested all C. flavius were negative and 46 percent C. libidinosus presented antibodies to arbovirus. Antibodies were detected for nine arbovirus (9/19). Seventeen heterotypic reactions were observed for at least two Or Flavirus and 15 for Alphavirus, at titers varying between 1:20 to 1:1280. Fifteen samples presented monotypic reaction for ILHV (n=4), MAYV (n=6), SLEV (n=1), ROCV (n=2), OROV (n=1) and MUCV (n=1). These results suggest that there was an intense arbovirus circulation in the studied population of captive capuchin monkeys.

Prevalencia serológica del virus de influenza A en cerdos en Argentina durante la temporada 2002: evaluación mediante inhibición de la hemaglutinación y ELISA / Seroprevalence of the swine Influenza virus in fattening pigs in Argentina in the 2002 season: evaluation by hemagglutination-inhibition and ELISA tests

Se evaluó la prevalencia serológica del virus de influenza mediante las pruebas de inhibición de la hemaglutinación (IHA) y ELISA para los subtipos H1N1 y H3N2 en 13 granjas porcinas de Argentina. Se compararon los resultados obtenidos mediante ambas pruebas en términos individuales y de establecimientos. La prevalencia individual por la técnica de IHA fue de 38,46% a 100% para H1 y de 7,69% a 100% para H3. Por la técnica de ELISA, la prevalencia individual fue de 2,33% a 6,9% para H1 y de 9,65% a 48% para H3. No se observaron diferencias significativas entre ambas técnicas a escala de granja (H1: p=0,20; H3: p=0,11). La concordancia entre las pruebas fue nula al tomar como unidad de referencia el animal (H1: 0,005; H3: 0,070), mientras que en términos de establecimiento fue escasa (H1: 0,350; H3: 0,235). Considerando la alta prevalencia individual obtenida por la prueba de IHA y la alta sensibilidad de esta técnica, se podría sugerir que en las poblaciones porcinas de la Argentina circularon cepas virales humanas o cepas porcinas con gran proximidad filogenética a las utilizadas en este estudio desde el año 2002.

The seroprevalence of the Influenza virus against H1N1 and H3N2 was determined by the hemagglutination-inhibition test (HI) and a commercial swine influenza ELISA kit, in 13 Argentinean swine herds. The results of within-herd and between-herd prevalence obtained by both tests were statistically correlated. The within-herd prevalence observed by the HI test varied from 38.46 to 100% against H1 and 7.69 to 100% for H3. When the within-herd prevalence was measured with the ELISA test, it varied from 2.33 to 6.9% for H1 and 9.65 to 48% for H3. No statistical differences were observed at herd level between HI and ELISA (H1: p = 0. 20; H3: p=0.11). No agreement between HI and ELISA detected prevalence was observed when the within-herd prevalence was compared (H1: 0.005; H3: 0.070), while the agreement at herd level was considered poor (H1: 0,350; H3: 0,235). The high within-herd prevalence values observed with the HI test and the high sensibility of this test might show that human strains or swine strains phylogenetically closely related to the humans strains used in the HI test in this study have been affecting the swine population since 2002.

Serosurveillance for Japanese encephalitis, Akabane, and Aino viruses for Thoroughbred horses in Korea

Recent global warming trends may have a significant impact on vector-borne viral diseases, possibly affecting vector population dynamics and disease transmission. This study measured levels of hemagglutination-inhibition (HI) antibodies against Japanese encephalitis virus (JEV) and neutralizing antibodies against Akabane virus (AKAV) and Aino virus (AINV) for Thoroughbred horses in Korea. Blood samples were collected from 989 racehorses in several provinces, between October 2005 and March 2007. Sera were tested using either an HI assay or a virus neutralization test. Approximately half (49.7%; 492/989) of the horses tested were antibody-positive for JEV. The HI titer against JEV was significantly correlated with racehorse age (p < 0.05). Horses with an HI antibody titer of 1: 160 or higher accounted for 3.9% of the animals tested, indicating that vectors transmitting arthropod- borne viruses bit relatively few horses. In contrast, 3.8% (19/497) and 19.5% (97/497) of horse sera collected in March 2007 were positive against AKAV and AINV, respectively. The presence of antibodies against AKAV and AINV may indicate the multiplication of AKAV and AINV in these horses.

The seroprevalence of Japanese encephalitis virus in goats raised in Korea

Japanese encephalitis virus (JEV) causes a mosquitoborne viral zoonosis that is becoming increasingly important to public health in east and south Asia. Although JEV is primarily associated with reproductive failure in swine, JEV infection can cause fever and headache in humans and is associated with aseptic meningitis and encephalitis. The exact mode of transmission, including host range and possible source of viral amplification within livestock, is still not completely clear. This study consisted of a serological survey of JEV infection in goats. A total of 804 goat serum samples were collected from 144 farms in Korea between May 2005 and May 2006. The incidence of positive cases was 12.1% (97 out of 804 goats). The seroprevalence of JEV infection in the 144 farms screened was 31.3% (45/144), indicating that JEV infection is frequent in goat farms in Korea. In addition, three districts of Korea (mainly in the southern region) had a higher seroprevalence of JEV compared to other areas. The results suggest that goats could be monitored epidemiologically as a sentinel animal for JEV transmission in Korea.

Development and evaluation of indirect ELISA for the detection of antibodies against Japanese encephalitis virus in swine

The Japanese encephalitis virus (JEV) is one of causative agents of reproductive failure in pregnant sows. An indirect enzyme-linked immunosorbent assay (I-ELISA) was examined for its potential use in the rapid monitoring of the JEV, and the results were compared with those from the hemagglutination inhibition (HI) and serum neutralization (SN) tests. The comparative analysis showed that the results of I-ELISA showed a significant correlation with the conventional HI (r = 0.867) and SN tests (r = 0.804), respectively. When the I-ELISA results were compared with the traditional diagnostic assays, the sensitivity of the I-ELISA was 94.3% with the HI test and 93.7% with the SN test, respectively. The specificity was found to be 81.4% and 80.0% with the HI and SN tests, respectively. To determine the applicability of I-ELISA in the field, the serum samples from 720 pigs were collected from 4 regions in Korea between July and August 2004. The results indicated that 21.7% of screened pigs were seropositive for the JEV. The seropositive rates of JEV in the 4 provinces were 12.6% in Gyeonggi, 45.0% in Gyeongnam, 16.7% in Jeonbuk, and 12.2% in Jeju. The I-ELISA methodology developed in this study was shown to have considerable sensitivity and specificity through a comparison with HI and the SN tests. Therefore, it might be one of convenient methods for screening a large number of samples in various fields.

Anti-human influenza protector antibody detected in horses as a zoonotic viruses

O objetivo deste estudo foi investigar em cavalos, a incidência do vírus influenza e seu ciclo de transmissão interespécies. Portanto, levantamento sorológico foi realizado em soro de cavalos, confrontados com ambas cepas, as específicas (eqüino) e não específicas (humana) deste vírus. Sangrias de cavalos realizadas nos anos de 1999 e de 2000, forneceram soros que, após tratamento com Caolim (20%) e hemácias de galo(50%) para remoção dos anticorpos inespecíficos, foram titulados contra ambas referidas cepas, através do teste de Inibição da Hemaglutinação (recomendado pela OMS). Os resultados, demonstraram que as respostas sorológicas dos cavalos apresentaram reação cruzada entre as cepas específicas e as não específicas. As porcentagens de títulos IH obtidos foram de 62,75% e de 60,65% para as cepas específicas A/Eq1 (H7N7) e A/Eq2 (H3N8), respectivamente. E às cepas não específicas essas porcentagens foram de: 79,05% para A (H1N1), de 94,45% para A (H3N2) e de 77,75% ao tipo B. O mais relevante nestes dados comparativos com vírus influenza, foi a alta porcentagem de resposta protetora à cepa não específica comparada àquela específica, detectada nos soros eqüinos. Considerando o fato de que o tipo B, deste vírus, ser restrito à espécie humana, portanto a resposta de proteção nos cavalos sugere uma direta transmissão interspécies, como em viroses zoonóticas. Os autores relatam pela primeira vez este tipo de evento no Brasil.

Biophysical characterization of Japanese encephalitis virus (KV1899) isolated from pigs in Korea

A virus strain, showing cytopathic effect in Vero cell, was isolated from plasma of a fattening pig in Gyeonggi province, Korea in October 1999. The evaluation of physicochemical/biological properties of the isolate showed that the virus, KV1899, inoculated suckling mouse showed paralysis and died within 7 days post-inoculation, the mouse brain suspension had hemagglutinating activity with goose RBC. Pathogenicity of isolate was carried out by intracranial and intraperitoneal inoculation of 3-4 weeks mice. The mice inoculated with isolate showed 10 4.5 LD50/ 0.03 ml and 10 3.0 LD50/0.5 ml according to the inoculation route. The isolate was identified as RNA and enveloped virus using IUDR and chloroform sensitivity test. The virus particles within the infected Vero cell were measured to be 40-50 nm in size by electron microscopy. The isolate was further characterized by immuno-fluorescence assay using Japanese encephalitis virus (JEV) specific monoclonal antibodies. Reverse transcription polymerase chain reaction (RT-PCR) revealed the presence of JE specific conserved sequences in this isolate. The artificially inoculated pigs had HI titer of 320 to 2,560 against JEV at 14 to 42 days post inoculation. We confirmed this isolate as Japanese encephalitis virus. It was the second isolation of JEV in pigs in Korea.

Influenza eqüina: avaliaçäo da resposta imune humoral, através das reaçöes de inibiçäo da hemaglutinaçäo e de hemólise radial simples, em soro de animais vacinados com vacina comercial e experimental / Equine influenza: evaluation of the humoral immune response through the hemagglutination inhibition and single radial haemolysis, in vaccinated horses with commercial and experimental vaccines

Foram avaliadas, através de testes de inibiçäo da hemaglutinaçäo (HI) e da hemólise radial simples (HRS), as respostas de anticorpos contra influenza em 4 lotes de eqüinos adultos. O grupo do lote 01 recebeu a imunizaçäo com 2 doses de vacina contra influenza, preparada experimentalmente no Instituto Butantan. Nos lotes 02 e 03, regularmente imunizados contra a influenza, foram administradas doses de reforço anual com a vacina comercial e com a vacina experimental, respectivamente. O lote 04 foi o grupo controle da avaliaçäo. Os resultados dos testes demonstraram que as médias de títulos de HRS e IH do lote 01 apresentaram diferenças ao nível de p < 0,001, com significante aumento das médias de títulos detectados nos soros após a 2a. imunizaçäo. Näo foram observadas diferenças significantes entre as médias de títulos de anticorpos em soros obtidos antes e após a dose de reforço anual dos eqüinos dos lotes 02 e 03, atribuindo-se a persistência de nível de anticorpos protetores mantida após 1 ano da imunizaçäo regular com vacina comercial. A conversäo sorológica dos eqüinos do lote 01, à persistência dos títulos de anticorpos nos eqüinos dos lotes 02 e 03 e, ainda, os baixos títulos de anticorpos verificados nos eqüinos näo vacinados do lote 04 comprovam o resultado da resposta sorológica das duas vacinas, a experimental e a comercial, avaliadas neste trabalho

Inoculación experimental del paramixovirus de ojo azul en ratas de laboratorio (cepa Wistar), vía intramuscular / Experimental inoculation of blue eye paramyxovirus in laboratory rats (Wistar) intramuscularly

Se utilizaron un total de 22 ratas (cepa Wistar) de las cuales 2 animales fueron testigo y 20 ratas fueron inoculadas con 1 ml del paramixovirus del ojo azul (POA) con un título de 10 5.55 DICC/ml, por vía intramuscular. El día 0 se tomaron muestras sangúineas por vía intracardiaca de 2 animales testigos, los cuales se sacrificaron posteriormente. Los días 1, 3, 5, 7, 10, 15, 20, 25, 30, 35 posinoculación (PI) se tomaron muestras de sangre para la detección serológica de anticuerpos contra POA, utilizando la técnica de inhibición de la hemaglutinación (IHA), seroneutralización (SN), para realizar biometrías hemáticas (BH) y la obtención de la capa flogística para aislamiento viral. Además se obtuvieron muestras de órganos (encéfalo, pulmón y tonsila) para intentar el aislamiento en tres líneas celulares (MDBK, PK-15, BT) e inmunofluorescencia en cultivo celular (IFCC); de estas mismas muestras se hicieron estudios histopatológicos (HP). Se recolectaron heces y orina durante los 35 días, para el aislamiento e IFCC. En los resultados de las pruebas serológicas se detectaron anticuerpos a partir del décimo día PI, con títulos de 1:4 hasta 1:256 para SN y de 1:8 hasta 1:64 para IHA. En el aislamiento viral de órganos, capas flogísticas, heces y orina se pudo aislar el virus durante todo el periodo de experimentación en las tres líneas celulares, coincidiendo estos resultados con las IFCC; las BH mostraron variación en los valores de neutrófilos, linfocitos y monocitos. No hubo presencia de lesiones significativas tanto macro como microscópicas

Prevalence of hemagglutination-inhibition and neutralizing antibodies to arboviruses in horses of java.

A study was conducted to measure the prevalence of hemagglutination-inhibition (HI) and neutralizing antibodies against two arboviruses (Chikungunya and Japanese encephalitis virus) in horses of Java, Indonesia. Blood specimens were collected from a sample of 112 horses at two stables: Pulo Mas, a racing track-horse complex, located in a residential area in North Jakarta, and Pamulang, a riding school, located in a rural environment of West Jaya. Sera were tested by the HI assay and plaque reduction neutralization test. JEV antibodies were detected by HI in 58 (52%) of the horses, while only 11 (10%) had Chikungunya antibodies by HI. The proportion of Pamulang horses infected with JEV (66%) was significantly higher than found among Pulo Mas horses (40%) screened (p < 0.01). Of the 58 horses with JEV antibodies by HI, 52 (90%) were found to have specific neutralization antibodies to JEV. HI and neutralization tests on horse sera indicated that the risk to alpha virus infections was minimal in horses surveyed from Java. However, there was a high risk of JEV infection among the same population.