Accuracy of Herdsmen Reporting versus Serologic Testing for Estimating Foot-and-Mouth Disease Prevalence

Herdsman-reported disease prevalence is widely used in veterinary epidemiologic studies, especially for diseases with visible external lesions; however, the accuracy of such reports is rarely validated. Thus, we used latent class analysis in a Bayesian framework to compare sensitivity and specificity of herdsman reporting with virus neutralization testing and use of 3 nonstructural protein ELISAs for estimates of foot-and-mouth disease (FMD) prevalence on the Adamawa plateau of Cameroon in 2000. Herdsman-reported estimates in this FMD-endemic area were comparable to those obtained from serologic testing. To harness to this cost-effective resource of monitoring emerging infectious diseases, we suggest that estimates of the sensitivity and specificity of herdsmen reporting should be done in parallel with serologic surveys of other animal diseases.Fil: Morgan, Kenton L.. University of Liverpool; Reino UnidoFil: Handel, Ian G.. University of Edinburgh; Reino UnidoFil: Tanya, Vincent N.. Institute of Agricultural Research for Development; Camerún. Ministry of Scientific Research and Innovation; CamerúnFil: Hamman, Saidou M.. Institute of Agricultural Research for Development; CamerúnFil: Nfon, Charles. Institute of Agricultural Research for Development; CamerúnFil: Bergmann, Ingrid Evelyn. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencias y Tecnología "Dr. Cesar Milstein"; Argentina. Pan American Foot and Mouth Disease Center; BrasilFil: Malirat, Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencias y Tecnología "Dr. Cesar Milstein"; Argentina. Pan American Foot and Mouth Disease Center; BrasilFil: Sorensen, Karl J.. Danish Veterinary Institute for Virus Research; DinamarcaFil: Bronsvoort, Barend M de C,. University of Edinburgh; Reino Unid

Variabilidad genética y antigénica del virus de la fiebre aftosa, serotipo O, entre aislamientos recuperados durante la replicación del virus en animales persistentemente infectados, y entre cepas de campo

La variación genética y antigénica en el virus de la fiebre aftosa, O1 Campos Brasil 1/58 (O1 C/58) se ha analizado en aislamientos consecutivos, recuperados durante un periodo de uno o dos años, a partir de cuatro bovinos con infección persistente, establecida en forma experimental. La comparación de los mapas bidimensionales de fragmentos resistentes a Rnasa T1, y de la secuencia de nucleótidos de la región que codifica para la proteína inmunogénica VP1, revelaron un aumento irregular de las fijaciones de mutaciones a medida que la infección avanzaba. El grado de variación con respecto a la cepa O1 C/58, usada originalmente para establecer la infección persistente, alcanzó valores máximos de 2,4 por ciento para el genoma total y de 1,4 por ciento para la secuencia de nucleótidos que codifica para la proteína VP1. La mayoría de los cambios no eran conservados entre aislamientos consecutivos. Estos resultados, junto con los valores substanciales de velocidad de variación genómica observados entre algunos pares de aislamientos recuperados con intervalos de tiempo muy cortos, indicaron la coexistencia de poblaciones heterogéneas, que predominaban unas sobre las otras en periodos irregulares, y que evolucionaban independientemente entre sí. No se observaron padrones de variación relacionados entre los cuatro animales. También fue evaluada la diversificación genética de cepas representativas de brotes de campo, serotipo O, ocurridos en regiones endémicas del sudeste de Brasil y del centro-este de Argentina entre los años 1958 y 1983. En base a los análisis de mapas bidimensionales de fragmentos resistentes a RNasa T1, los aislamientos mostraron diferencias respecto de la cepa O1 C/58, con valores que fluctuaban entre 0,7 por ciento y 4,0 por ciento de variación, y los valores registrados en base a la secuencia de nucleótidos que codifica para la proteína VP1 fluctuaron desde 1,0 por ciento hasta 17,2 por ciento. La variación genómica registrada era independiente del tiempo transcurrido entre los aislamientos, y los cambios no eran acumulativos. Estos resultados sugieren que las variantes no emergen sucesivamente en el campo, y que probablemente representan padrones independientes de evolución, donde podrían intervenir las infecciones persistentes

Genetic and antigenic variability of foot-and-mouth disease virus, serotype o, among isolates recovered during viral replication in persistently infected cattle, and among field isolates

La variación genética y antigénica en el virus de la fiebre aftosa, O1 Campos Brasil 1/58 (O1 C/58) se ha analizado en aislamientos consecutivos, recuperados durante un periodo de uno o dos años, a partir de cuatro bovinos con infección persistente, establecida en forma experimental. La comparación de los mapas bidimensionales de fragmentos resistentes a Rnasa T1, y de la secuencia de nucleótidos de la región que codifica para la proteína inmunogénica VP1, revelaron un aumento irregular de las fijaciones de mutaciones a medida que la infección avanzaba. El grado de variación con respecto a la cepa O1 C/58, usada originalmente para establecer la infección persistente, alcanzó valores máximos de 2,4 por ciento para el genoma total y de 1,4 por ciento para la secuencia de nucleótidos que codifica para la proteína VP1. La mayoría de los cambios no eran conservados entre aislamientos consecutivos. Estos resultados, junto con los valores substanciales de velocidad de variación genómica observados entre algunos pares de aislamientos recuperados con intervalos de tiempo muy cortos, indicaron la coexistencia de poblaciones heterogéneas, que predominaban unas sobre las otras en periodos irregulares, y que evolucionaban independientemente entre sí. No se observaron padrones de variación relacionados entre los cuatro animales. También fue evaluada la diversificación genética de cepas representativas de brotes de campo, serotipo O, ocurridos en regiones endémicas del sudeste de Brasil y del centro-este de Argentina entre los años 1958 y 1983. En base a los análisis de mapas bidimensionales de fragmentos resistentes a RNasa T1, los aislamientos mostraron diferencias respecto de la cepa O1 C/58, con valores que fluctuaban entre 0,7 por ciento y 4,0 por ciento de variación, y los valores registrados en base a la secuencia de nucleótidos que codifica para la proteína VP1 fluctuaron desde 1,0 por ciento hasta 17,2 por ciento. La variación genómica registrada era independiente del tiempo transcurrido entre los aislamientos, y los cambios no eran acumulativos. Estos resultados sugieren que las variantes no emergen sucesivamente en el campo, y que probablemente representan padrones independientes de evolución, donde podrían intervenir las infecciones persistentes.Genetic and antigenic variation in foot-and-mouth disease virus O1 Campos Brasil 1/58 (O1 C/58) has been analyzed in consecutive isolates recovered over a one- or two-year period from four cattle with experimental persistent infections. Comparisons of RNase T1 two-dimensional maps and nucleotide sequences of the VP1-coding region revealed an oscillatory increase in the fixation of mutations as the infection progressed. The degree of variation with respect to the strain O1 C/58 used originally to establish the persistent infection, reached values of up to 2,4 per centum for the overall genome, and 1,4 per centum for the nucleotide sequence of the VP1-coding region. Most changes were not conserved in consecutive isolates. These results, together with the substantial rates of genomic variation observed between some pairs of strains recovered at close time periods, suggested the coexistence of heterogeneous populations in which variants predominate at irregular time intervals and evolve independently from each other. Furthermore, non-related patterns of variation were observed in the four animals. Genetic diversification of representative strains from major serotipe O outbreaks in endemic disease regions of southeastern Brazil and central-eastern Argentina between 1958 and 1983, was evaluated. On the basis of oligonucleotide fingerprinting, isolates showed variations, with respect to the early strain O1 C/58, ranging between 0.7 per centum and 4.0 per centum, and values between 1.0 per centum and 17.2 per centum on the basis of nucleotide sequencing of part of the VP1-coding region. The extent of differences among the genomes was independent of the time elapsed between viral isolations. Moreover, changes did not accumulate in subsequent samples. These results suggested that variants did not emerge successively in the field, and probably represent independent patterns of evolution, where persistent infections might be involved.Fil:Malirat, Viviana. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

First full-length genomic sequence of a hepatitis A virus isolated in Argentina shows recombination between subgenotypes IA and IB

A hepatitis A virus (HAV) recovered in Argentina from a stool sample of a sick child in the year 2006 (HAV-Arg/06) was entirely sequenced. Phylogenetic analysis included the HAV-Arg/06 sequence in subgenotype IA, either considering the usual VP1-2A variable junction fragment or the full length nucleotide sequence. Interestingly, a recombination event with subgenotype IB, involving a portion of the 2C-3A nonstructural proteins coding region (nucleotides 4961-5140) was detected using specific software. Only subgenotype IA strains have been detected in Argentina or Uruguay, whereas subgenotype IA and IB strains have been reported to circulate in Brazil. Although recombination has been given an important role in the evolution of picornaviruses, there have been only a few reports of its involvement in the evolution of HAV, probably due to the limited number of complete HAV sequences available. This study constitutes the first report of a full-length HAV sequence in Argentina and the third in South America, after the sequence of the IA isolate HAV5 from Uruguay and the IB isolate HAF-203 from Brazil. The availability of new sequence data covering the complete HAV genome will help establish a more consistent genetic relatedness among HAV isolates and the role of recombination in its evolution.Fil: Aguirre Sebastian. Centro de Ciencia y Tecnología Dr. César Milstein; Argentina ; ArgentinaFil: Malirat, Viviana. Centro de Ciencia y Tecnología Dr. César Milstein; ArgentinaFil: Scodeller, Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Mattion, Nora Marta. Centro de Ciencia y Tecnología Dr. César Milstein; Argentin

Challenges in foot-and-mouth disease virus strain selection as an input to attain broad vaccine intraserotype cross-protection

Introduction: Vaccination against foot-and-mouth disease virus is regarded as the most effective way to prevent disease. Selection of appropriate vaccine strains is challenging due to lack of cross-protection between serotypes and incomplete protection between some strains within a serotype. Vaccine effectiveness can be affected by vaccine formulation, vaccination approaches, and also by emerging field variants. Therefore, a precise evaluation of the protective capacity of the selected vaccine virus is essential. Areas covered: This article discusses the limitations of currently in use in vitro methods to assess the protective capacity of vaccine strains. It includes the assessment of well-established South American vaccine strains, O1/Campos and A24/Cruzeiro, against outbreaks/emergencies in the continent, as well as against recent isolates from East and Southeast Asia. Expert opinion: In vitro methods, and particularly r1 values, used to evaluate the protective capacity of vaccine strains are not conclusive and do not cover the variety of field scenarios. At present, an option when facing emergencies could be to use well-established vaccine strains with broad antigenic/immunogenic coverage, including conditions that lead to increased coverage such as vaccine formulations and vaccination schemes.Fil: Bergmann, Ingrid Evelyn. Ministerio de Produccion y Trabajo. Secretaria de Gobierno de Agroindustria. Servicio Nacional de Sanidad y Calidad Agroalimentaria. Centro de Virologia Animal. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Centro de Virologia Animal.; ArgentinaFil: Malirat, Viviana. Ministerio de Produccion y Trabajo. Secretaria de Gobierno de Agroindustria. Servicio Nacional de Sanidad y Calidad Agroalimentaria. Centro de Virologia Animal. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Centro de Virologia Animal.; ArgentinaFil: Pedemonte, Andrea. Ministerio de Agricultura, Ganadería, Pesca y Alimento. Servicio Nacional de Sanidad y Calidad Agroalimentaria; ArgentinaFil: Maradei, Eduardo. Ministerio de Agricultura, Ganadería, Pesca y Alimento. Servicio Nacional de Sanidad y Calidad Agroalimentaria; Argentin

Molecular epidemiology of foot-and-mouth disease virus type A in South America

A databank of 78 VP1 complete sequences of type A foot-and-mouth disease virus (FMDV) from South American isolates was constructed. Forty-nine samples corresponded to FMDV that circulated between the years 1999–2008, mainly in Venezuela, where most type A outbreaks have occurred lately and twenty-nine to strains historically relevant for the continent. The phylogenetic analysis showed that all South American FMDV belonged to the Euro-SA topotype. Sixteen subgenotypes could be identified, based on a 15% nucleotide divergence cut-off criterion: eight are extinguished, three were active until the year 2002 and the remaining five circulated in Venezuela during the years 2001–2007, illustrating the potential for FMDV diversification under appropriate selective pressure. The last emergencies reported in already-free areas of Colombia in 2004 and 2008 were closely related to isolates acting in Venzuela. Evidence of positive selection over codon 170, within the immunogenic site 4 of VP1 protein, was recorded. A codon deletion in amino acid position 142, within the G–H loop, was found in some isolates within subgenotypes 14, 15 and 16. Conversely amino acid deletion 197 was restricted to all isolates within a particular genetic cluster. The present work is the first comprehensive phylogenetic analysis of FMDV type A in South America, filling a gap of knowledge with respect to both, historical and acting viruses. The results provided evidence that supports the ecosystem dynamics in the region, and also served as an input to establish genetic links of emergencies in already-declared free areas, highlighting the need for strengthening control activities.Fil: Malirat, Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. Cesar Milstein". Fundación Pablo Cassara. Instituto de Ciencia y Tecnología ; Argentina. Pan American Foot-and-Mouth Disease Center; BrasilFil: Bergmann, Ingrid Evelyn. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. Cesar Milstein". Fundación Pablo Cassara. Instituto de Ciencia y Tecnología ; Argentina. Pan American Foot-and-Mouth Disease Center; BrasilFil: Campos, Renata de Mendonça. Pan American Foot-and-Mouth Disease Center; Brasil. Instituto Oswaldo Cruz; BrasilFil: Conde, Florangel. Centro Nacional de Investigaciones Agropecuarias. Instituto Nacional de Investigaciones Agrícolas; VenezuelaFil: Quiroga, José Luis. Laboratorio de Investigación y Diagnóstico Veterinario; BoliviaFil: Villamil, Mariluz. Laboratorio Nacional de Diagnóstico Veterinario; ColombiaFil: Salgado, Gustavo. Instituto de Medicina e Higiene Tropical ‘‘Izquieta Perez’; EcuadorFil: Ortiz, Salomón. Servicio Nacional de Sanidad Animal; Per

Broad immunogenic spectrum of monovalent and trivalent foot-and-mouth disease virus vaccines containing O1 campos, A24 cruzeiro and A Argentina 2001 strains against circulating viral lineages in cattle and pigs

FMD remains endemic in many Asian and African countries where multiple variants of serotypes O and A, among others, currently circulate. Due to lack of cross-protection between serotypes and incomplete protection between some strains even within a serotype, an important challenge for the application of effective vaccination programs is to select highly immunogenic and widely cross-reactive vaccine strains. Adaptation of a candidate field virus for use as a vaccine can be quite complex, so that whenever possible, the use of well-established vaccine viruses could have enormous advantages. FMD vaccine strains harmonized for use in South America have shown excellent results in FMD control, not only in the region, where it is still used systematically as a preventive measure, but also more recently in some Asian countries. To gain further insight into the immunogenic spectrum of these strains, VN tests (VNT) were performed with sera from cattle and/or pigs vaccinated with monovalent (type O) or trivalent (types O and A) formulations against 122 type O and 32 type A field viruses isolated from 35 countries in Asia and Africa, belonging to different lineages. Almost all VNT titers obtained were within the expected protective level, indicating the wide immunogenic spectrum of high potency FMD vaccines formulated with O1 Campos, A24 Cruzeiro and A Argentina 2001 South American vaccine strains belonging to EURO-SA topotypes against currently active viruses from other topotypes. These in vitro results are in line with previously reported in vivo challenge tests in pigs against three A/ASIA/Sea-97 isolates and two isolates belonging to type O lineages O/SEA/Mya-98 and O/ME-SA/Ind-2001e.Fil: Malirat, Viviana. Ministerio de Produccion y Trabajo. Secretaria de Gobierno de Agroindustria. Servicio Nacional de Sanidad y Calidad Agroalimentaria. Centro de Virologia Animal. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Centro de Virologia Animal.; ArgentinaFil: Caldevilla, Cecilia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Biogénesis Bagó; ArgentinaFil: Cardillo, Sabrina Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Biogénesis Bagó; ArgentinaFil: Espinoza, Ana María. Biogénesis Bagó; ArgentinaFil: Galdo Novo, Sabrina. Ministerio de Agricultura, Ganadería, Pesca y Alimento. Servicio Nacional de Sanidad y Calidad Agroalimentaria; ArgentinaFil: Taffarel, Ana. Ministerio de Agricultura, Ganadería, Pesca y Alimento. Servicio Nacional de Sanidad y Calidad Agroalimentaria; ArgentinaFil: Barrios Benito, Melanie. Ministerio de Agricultura, Ganadería, Pesca y Alimento. Servicio Nacional de Sanidad y Calidad Agroalimentaria; ArgentinaFil: Bergmann, Ingrid Evelyn. Ministerio de Produccion y Trabajo. Secretaria de Gobierno de Agroindustria. Servicio Nacional de Sanidad y Calidad Agroalimentaria. Centro de Virologia Animal. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Centro de Virologia Animal.; Argentin

Antigenic and immunogenic spectrum of foot and mouth disease vaccine strain O1 Campos against representative viruses of topotypes that circulated in Asia over the past decade

Identifying vaccine strains to control outbreaks of foot-and-mouth disease virus that could spread to new regions is essential for contingency plans. This is the first report on the antigenic/immunogenic relationships of the South American O1/Campos vaccine strain with representative isolates of the three currently active Asian type O topotypes. Virus neutralization tests using O1/Campos post-vaccination sera derived from cattle and pigs predicted for both species acceptable cross-protection, even after single vaccination, established by r1 values and by expectancy of protection using monovalent or polyvalent vaccines. The results indicate that effective oil vaccines containing the O1/Campos strain can be used against Asian isolates, expanding the scope of O1/Campos strain included in vaccine banks to control emergencies caused by Asian viruses, even on single-dose vaccination, and to cover the need of effective vaccines in Asia during systematic vaccination.Fil: Galdo Novo, Sabrina. Ministerio de Agricultura, Ganadería, Pesca y Alimento. Servicio Nacional de Sanidad y Calidad Agroalimentaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Malirat, Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología ; ArgentinaFil: Maradei, Eduardo D.. Ministerio de Agricultura, Ganadería, Pesca y Alimento. Servicio Nacional de Sanidad y Calidad Agroalimentaria; ArgentinaFil: Espinoza, Ana María. Biogénesis Bagó; ArgentinaFil: Smitsaart, Eliana. Biogénesis Bagó; ArgentinaFil: Pedemonte, Andrea. Ministerio de Agricultura, Ganadería, Pesca y Alimento. Servicio Nacional de Sanidad y Calidad Agroalimentaria; ArgentinaFil: Mattion, Nora Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología ; ArgentinaFil: Bergmann, Ingrid Evelyn. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología ; Argentin