RESUMEN
The objective of this work was to comparatively study the tissue tropism and the associated pathology of 2 autochthonous small ruminant lentivirus (SRLV) field strains using an experimental infection in sheep through the bone marrow. Fifteen male, SRLV-free lambs of the Rasa Aragonesa breed were inoculated with strain 697 (nervous tissue origin, animals A1-A6), with strain 496 (articular origin, animals B1-B6), or with uninfected culture medium (C1-C3). Clinical, serologic, and polymerase chain reaction (PCR) evaluations were performed periodically. Two lambs from each infected group and a control animal were euthanized at 134, 273, and 319 days postinfection. Tissues were analyzed by gross and histopathologic evaluation; immunohistochemistry for CD3, CD4, CD8, CD68, and FoxP3 cell markers; lung morphometric evaluation; and tissue proviral quantification by PCR. All infected animals became positive either by enzyme-linked immunosorbent assay and/or PCR, with group B lambs showing the highest serologic values and more consistently positive PCR reactions. Group A lambs showed representative lung lesions but only mild histopathologic changes in the central nervous system (CNS) or in carpal joints. Contrarily, group B lambs demonstrated intense carpal arthritis and interstitial pneumonia but an absence of lesions in the CNS. Proviral copies in tissues were detected only in group B lambs. Experimental infection with these SRLV strains indicates that strain 496 is more virulent than strain 697 and more prone to induce arthritis, whereas strain 697 is more likely to reproduce encephalitis in Rasa Aragonesa lambs. Host factors as well as viral factors are responsible for the final clinicopathologic picture during SRLV infections.
Asunto(s)
Médula Ósea/virología , Infecciones por Lentivirus/veterinaria , Lentivirus Ovinos-Caprinos/patogenicidad , Tropismo Viral , Animales , Médula Ósea/patología , Sistema Nervioso Central/patología , Sistema Nervioso Central/virología , Ensayo de Inmunoadsorción Enzimática/veterinaria , Articulaciones/patología , Articulaciones/virología , Infecciones por Lentivirus/patología , Infecciones por Lentivirus/virología , Pulmón/patología , Pulmón/virología , Masculino , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Ovinos/virología , Tropismo Viral/fisiologíaRESUMEN
Small ruminant lentiviruses include viruses with diverse genotypes that frequently cross the species barrier between sheep and goats and that display a great genetic variability. These characteristics stress the need to consider the whole host range and to perform local surveillance of the viruses to opt for optimum diagnostic tests, in order to establish control programmes. In the absence of effective vaccines, a comprehensive knowledge of the epidemiology of these infections is of major importance to limit their spread. This article intends to cover these aspects and to summarise information related to characteristics of the viruses, pathogenesis of the infection and description of the various syndromes produced, as well as the diagnostic tools available, the mechanisms involved in transmission of the pathogens and, finally, the control strategies that have been designed until now, with remarks on the drawbacks and the advantages of each one. We conclude that there are many variables influencing the expected cost and benefits of control programs that must be evaluated, in order to put into practice measures that might lead to control of these infections.
Asunto(s)
Infecciones por Lentivirus/veterinaria , Lentivirus/genética , Rumiantes/virología , Enfermedades de las Ovejas/diagnóstico , Animales , Enfermedades de las Cabras/diagnóstico , Enfermedades de las Cabras/etiología , Enfermedades de las Cabras/prevención & control , Cabras , Especificidad del Huésped , Interacciones Huésped-Patógeno , Lentivirus/fisiología , Infecciones por Lentivirus/diagnóstico , Infecciones por Lentivirus/etiología , Infecciones por Lentivirus/prevención & control , Ovinos , Enfermedades de las Ovejas/etiología , Enfermedades de las Ovejas/prevención & control , Oveja DomésticaRESUMEN
We describe the clinicopathologic features of an arthritis outbreak in sheep induced by small ruminant lentivirus (SRLV), linked to the presence of a new SRLV isolate phylogenetically assigned to caprine arthritis encephalitis virus-like subgroup B2. Thirteen SRLV seropositive Rasa Aragonesa adult ewes were selected from 5 SRLV highly infected flocks (mean seroprevalence, 90.7%) for presenting uni- or bilateral chronic arthritis in the carpal joint. A complete study was performed, including symptomatology, histopathology, immunocytochemistry, immunohistochemistry, in situ hybridization, and microbiology. The carpus was the joint almost exclusively affected, with 10 sheep (76%) showing a moderate increase in carpal joint size (diameter range, 18-20 cm; normal range, 15-16 cm) without signs of locomotion problems and with 3 ewes (23%) showing severe inflammation with marked increase in diameter (21-24 cm), pain at palpation, and abnormal standing position. Grossly, chronic proliferative arthritis was observed in affected joints characterized by an increased thickness of the synovial capsule and synovial membrane proliferation. Microscopically, synovial membrane inflammation and proliferation and hyperplasia of synoviocytes were observed. More positive cases of SLRV infection were detected by immunocytochemistry of articular fluid than of bronchoalveolar lavage fluid. Immunohistochemistry and in situ hybridization also detected positive cells in the subsynovial connective tissue, lung, mediastinal lymph node, mammary gland, and mammary lymph node. All animals were negative for the presence of Mycoplasma or other bacteria in the articular space. The present outbreak likely represents an adaptation of a caprine virus to sheep. Our results underline the importance of the arthritis induced by SRLV in sheep, a clinical form that might be underestimated.
Asunto(s)
Artritis/veterinaria , Infecciones por Lentivirus/veterinaria , Lentivirus/fisiología , Enfermedades de las Ovejas/patología , Animales , Artritis/patología , Artritis/virología , Virus de la Artritis-Encefalitis Caprina/genética , Virus de la Artritis-Encefalitis Caprina/fisiología , Genotipo , Lentivirus/genética , Infecciones por Lentivirus/patología , Infecciones por Lentivirus/virología , Filogenia , Estudios Seroepidemiológicos , Ovinos , Enfermedades de las Ovejas/virología , Especificidad de la Especie , Membrana Sinovial/virologíaRESUMEN
A control system for Visna/maedi virus (VMV) infection based on serologic segregation and management strategies was applied in an infected Spanish dairy Manchega breed sheep flock (n=670) that was affected by a severe respiratory process associated to VMV. The control started in 2004 and consisted on the serological study of animals, segregation in two different flocks (seropositive and seronegative), separate management of flocks, selection of young female lambs for replacement only from seronegative ewes offspring, immediate removal of seropositive animals detected in the seronegative flock and a management tending toward the reduction and final culling of the seropositive flock. The serological control was repeated yearly or twice a year, approximately. Initial VMV seroprevalence of the undivided flock was 66.4% (January 2004) that descended to 47.3%, 12.8%, 2.2% and 0.2% between July 2004 and May 2006. Residual seroprevalence fluctuated slightly thereafter with a peak of 2.2% in April 2008. After segregation, number of animals in the seronegative flock was 378 that descended to 323 in October 2005. Since then, this number has increased steadily reaching 650 sheep in December 2011. The seropositive flock was progressively reduced by culling until its total disappearance in June 2010. This work presents the detailed results obtained in the control strategy against VMV in a single dairy sheep flock by implementing a segregation system based on serologic testing. The system is highly successful, as it reduces to residual levels VMV infection in about two years without the need of culling a high number of animals, as required by other methods. Moreover, the original size flock was been recovered within 8 years and has led to a subjective improvement of animal health and welfare in the flock. The residual seroprevalence could be eliminated at this stage by applying more sensitive molecular or other serological techniques to reach eradication.
Asunto(s)
Industria Lechera/métodos , Neumonía Intersticial Progresiva de los Ovinos/prevención & control , Virus Visna-Maedi/fisiología , Visna/prevención & control , Animales , Anticuerpos Antivirales/sangre , Ensayo de Inmunoadsorción Enzimática/veterinaria , Femenino , Neumonía Intersticial Progresiva de los Ovinos/virología , Prevalencia , Estudios Seroepidemiológicos , Ovinos , España/epidemiología , Visna/virologíaRESUMEN
A single broadly reactive standard ELISA is commonly applied to control small ruminant lentivirus (SRLV) spread, but type specific ELISA strategies are gaining interest in areas with highly prevalent and heterogeneous SRLV infections. Short (15-residue) synthetic peptides (n=60) were designed in this study using deduced amino acid sequence profiles of SRLV circulating in sheep from North Central Spain and SRLV described previously. The corresponding ELISAs and two standard ELISAs were employed to analyze sera from sheep flocks either controlled or infected with different SRLV genotypes. Two outbreaks, showing SRLV-induced arthritis (genotype B2) and encephalitis (genotype A), were represented among the infected flocks. The ELISA results revealed that none of the assays detected all the infected animals in the global population analyzed, the assay performance varying according to the genetic type of the strain circulating in the area and the test antigen. Five of the six highly reactive (57-62%) single peptide ELISAs were further assessed, revealing that the ELISA based on peptide 98M (type A ENV-SU5, consensus from the neurological outbreak) detected positives in the majority of the type-A specific sera tested (Se: 86%; Sp: 98%) and not in the arthritic type B outbreak. ENV-TM ELISAs based on peptides 126M1 (Se: 82%; Sp: 95%) and 126M2 0,65 0.77 (Se: 68%; Sp: 88%) detected preferentially caprine arthritis encephalitis (CAEV, type B) and visna/maedi (VMV, type A) virus infections respectively, which may help to perform a preliminary CAEV vs. VMV-like typing of the flock. The use of particular peptide ELISAs and standard tests individually or combined may be useful in the different areas under study, to determine disease progression, diagnose/type infection and prevent its spread.
Asunto(s)
Ensayo de Inmunoadsorción Enzimática/veterinaria , Infecciones por Lentivirus/veterinaria , Enfermedades de las Ovejas/diagnóstico , Secuencia de Aminoácidos , Animales , Anticuerpos Antivirales/sangre , Antígenos Virales/genética , Virus de la Artritis-Encefalitis Caprina/genética , Virus de la Artritis-Encefalitis Caprina/inmunología , Brotes de Enfermedades/veterinaria , Ensayo de Inmunoadsorción Enzimática/métodos , Ensayo de Inmunoadsorción Enzimática/estadística & datos numéricos , Genes gag , Cabras , Infecciones por Lentivirus/diagnóstico , Infecciones por Lentivirus/epidemiología , Datos de Secuencia Molecular , Filogenia , Neumonía Intersticial Progresiva de los Ovinos/diagnóstico , Neumonía Intersticial Progresiva de los Ovinos/epidemiología , Neumonía Intersticial Progresiva de los Ovinos/inmunología , Ovinos , Enfermedades de las Ovejas/epidemiología , Enfermedades de las Ovejas/inmunología , Oveja Doméstica , España/epidemiología , Proteínas Virales/genética , Proteínas Virales/inmunología , Visna/diagnóstico , Visna/epidemiología , Visna/inmunología , Virus Visna-Maedi/genética , Virus Visna-Maedi/inmunologíaRESUMEN
The restrictive properties of tripartite motif-containing 5 alpha (TRIM5α) from small ruminant species have not been explored. Here, we identify highly similar TRIM5α sequences in sheep and goats. Cells transduced with ovine TRIM5α effectively restricted the lentivirus visna/maedi virus DNA synthesis. Proteasome inhibition in cells transduced with ovine TRIM5α restored restricted viral DNA synthesis, suggesting a conserved mechanism of restriction. Identification of TRIM5α active molecular species may open new prophylactic strategies against lentiviral infections.
Asunto(s)
Proteínas Portadoras/metabolismo , Enfermedades de las Cabras/inmunología , Enfermedades de las Ovejas/inmunología , Virus Visna-Maedi/fisiología , Visna/metabolismo , Secuencia de Aminoácidos , Animales , Proteínas Portadoras/química , Proteínas Portadoras/genética , Enfermedades de las Cabras/genética , Enfermedades de las Cabras/metabolismo , Enfermedades de las Cabras/virología , Cabras , Datos de Secuencia Molecular , Filogenia , Alineación de Secuencia , Ovinos , Enfermedades de las Ovejas/genética , Enfermedades de las Ovejas/metabolismo , Enfermedades de las Ovejas/virología , Visna/genética , Visna/virologíaAsunto(s)
Aneurisma Roto/cirugía , Aneurisma/cirugía , Anomalías Cardiovasculares/cirugía , Trastornos de Deglución/cirugía , Procedimientos Endovasculares , Arteria Subclavia/anomalías , Aneurisma/complicaciones , Aneurisma Roto/complicaciones , Anomalías Cardiovasculares/complicaciones , Trastornos de Deglución/complicaciones , Humanos , Masculino , Persona de Mediana Edad , Arteria Subclavia/cirugíaRESUMEN
An extensive outbreak characterized by the appearance of neurological symptoms in small ruminant lentivirus (SRLV) infected sheep has been identified in Spain, but the genetic characteristics of the strain involved and differential diagnostic tools for this outbreak remain unexplored. In this work, 23 Visna-affected naturally infected animals from the outbreak, 11 arthritic animals (both groups presenting anti-Visna/Maedi virus serum antibodies), and 100 seronegative animals were used. Eight of the Visna-affected animals were further studied post-mortem by immunohistochemistry. All had lesions in spinal cord, being the most affected part of the central nervous system in six of them. A representative strain of the outbreak was isolated. Together with other proviral sequences from the outbreak the virus was assigned to genotype A2/A3. In vitro culture of the isolate revealed that viral production was slow/low in fibroblast-like cells but it was high in blood monocyte-derived macrophages. The long terminal repeat (LTR) of the viral genome of this isolate lacked an U3-duplication, but its promoter activity in fibroblast-like cells was normal compared to other strains. Thus, viral production could not be inferred from the LTR promoter activity in this isolate. Analysis of the viral immunodominant epitopes among SRLV sequences of the outbreak and other known sequences allowed the design of a synthetic SU peptide ELISA that detected the Visna affected animals, representing a tool of epidemiological interest to control viral spread of this highly pathogenic strain.
Asunto(s)
Brotes de Enfermedades/veterinaria , Virus Visna-Maedi/genética , Visna/diagnóstico , Visna/virología , Animales , Anticuerpos Antivirales/sangre , Ensayo de Inmunoadsorción Enzimática/veterinaria , Femenino , Macrófagos/virología , Masculino , Ovinos , Oveja Doméstica , España/epidemiología , Secuencias Repetidas Terminales , Visna/epidemiología , Virus Visna-Maedi/inmunología , Virus Visna-Maedi/aislamiento & purificaciónRESUMEN
Nucleotide sequences of small ruminant lentiviruses (SRLVs) were determined in sheep and goats, including progeny of imported animals, on a farm in Mexico. On the basis of gag-pol, pol, env and LTR sequences, SRLVs were assigned to the B1 subgroup, which comprises caprine arthritis-encephalitis virus (CAEV)-like prototype sequences mainly from goats. In comparison with CAEV-like env sequences of American and French origin, two putative recombination events were identified within the V3-V4 and V4-V5 regions of the env gene of a full length SRLV sequence (FESC-752) derived from a goat on the farm.
Asunto(s)
Virus de la Artritis-Encefalitis Caprina/clasificación , Virus de la Artritis-Encefalitis Caprina/genética , Genes Virales , Enfermedades de las Cabras/virología , Infecciones por Lentivirus/veterinaria , Recombinación Genética , Enfermedades de las Ovejas/virología , Animales , Secuencia de Bases , Genes env , Genes gag , Genes pol , Cabras , Infecciones por Lentivirus/virología , México , Datos de Secuencia Molecular , Filogenia , Alineación de Secuencia , Ovinos , Oveja Doméstica , Secuencias Repetidas TerminalesRESUMEN
The incidence of seroconversion to visna/maedi virus (VMV) infection and its relationship with management and sheep building structure was investigated in 15 dairy sheep flocks in Spain during 3-7years. Incidence rates were 0.09 per sheep-year at risk in semi-intensive Latxa flocks and 0.44 per sheep-year at risk in intensive Assaf flocks and was greatest for the one year old Assaf replacement flock. Separate multivariable models developed for replacement and adult flocks indicated that in both cases seroconversion was strongly associated to direct contact exposure to infected sheep and to being born to a seropositive dam. The latter effect was independent of the mode of rearing preweaning and the risk of seroconversion was similar for sheep fed colostrum and milk from a seropositive or a seronegative dam. These results are further evidence of the efficiency of horizontal VMV transmission by close contact between sheep and also suggest a inheritable component of susceptibility and resistance to infection. In contrast, indirect aerogenous contact with seropositive sheep was not associated with seroconversion as evidenced in replacement sheep housed in separate pens in the same building as adult infected sheep for one year. Consequently, VMV may not be efficiently airborne over short distances and this is important for control of infection. Moreover, there was no relationship between seroconversion and shed open areas. The latter could be related to having examined few flocks in which high infection prevalence dominated the transmission process while ventilation, may depend on a variety of unrecorded factors whose relationship to infection needs to be further investigated.
Asunto(s)
Vivienda para Animales/normas , Neumonía Intersticial Progresiva de los Ovinos/epidemiología , Enfermedades de las Ovejas/epidemiología , Virus Visna-Maedi/aislamiento & purificación , Visna/epidemiología , Envejecimiento , Animales , Anticuerpos Antivirales/sangre , Cruzamiento/normas , Calostro/virología , Industria Lechera/normas , Femenino , Incidencia , Leche/virología , Neumonía Intersticial Progresiva de los Ovinos/sangre , Neumonía Intersticial Progresiva de los Ovinos/prevención & control , Ovinos , Enfermedades de las Ovejas/prevención & control , Enfermedades de las Ovejas/virología , España/epidemiología , Visna/sangre , Visna/prevención & controlRESUMEN
A serological survey of Visna/maedi virus (VMV) infection involving 274,048 sheep from 554 flocks was undertaken during 2002-2007 in Aragón, North-East Spain. One hundred and two of these flocks enrolled in a VMV control programme to reduce seroprevalence by selecting replacement lambs from seronegative dams and gradual culling of seropositive sheep. Twenty-five flocks were also visited to collect flock management and housing data. All study flocks had seropositive animals and 52.8% of animals tested were seropositive. Among flocks that joined the control programme 66 adopted the proposed measures and reduced seroprevalence significantly by between 26.1% and 76.9% whereas the remaining 36 flocks did not apply the measures and seroprevalence significantly increased. Seroprevalence increased with flock size and the number of days the sheep were housed, and decreased with increasing weaning age and shed open area, suggesting a reduced risk of VMV infection in sheep associated with better ventilation. At the end of the period, 24 flocks were certified as VMV-controlled with a seroprevalence <5%, and seven as VMV-free with 0% seroprevalence. These are the first officially recognised VMV-free flocks in Spain and represent a nucleus of VMV-free replacement animals for other flocks. Moreover, they are evidence of the possibility of eliminating VMV infection without resorting to whole-flock segregation or culling of seropositive sheep.
Asunto(s)
Neumonía Intersticial Progresiva de los Ovinos , Enfermedades de las Ovejas , Virus Visna-Maedi/aislamiento & purificación , Visna , Crianza de Animales Domésticos/métodos , Animales , Vivienda para Animales , Neumonía Intersticial Progresiva de los Ovinos/epidemiología , Neumonía Intersticial Progresiva de los Ovinos/prevención & control , Factores de Riesgo , Estudios Seroepidemiológicos , Ovinos , Enfermedades de las Ovejas/epidemiología , Enfermedades de las Ovejas/prevención & control , Enfermedades de las Ovejas/virología , España/epidemiología , Ventilación , Visna/epidemiología , Visna/prevención & controlRESUMEN
Antibody-based diagnosis of small ruminant lentiviruses (SRLVs) has been efficiently achieved using serum and milk, but not semen, for which polymerase chain reaction (PCR) has been proposed as a confirmatory technique. This work, involving 296 ovine (Ovis aries) and caprine (Capra hircus) semen donors, investigates whether seminal fluid (SF) can be reliably used in antibody-based SRLV diagnosis. First, a gold standard was established to assess the infection status and determine the sensitivity and specificity of three commercial enzyme-linked immunosorbent assays (ELISAs) in serum testing using Western blot and PCR as confirmatory tests. For SF testing, both gold standard and serum testing results were used as reference. The performance of SF testing was affected not only by the ELISA assay sensitivity (related to antigen spectrum) compared with that of the gold standard (as it occurred in serum testing) but also by SF sample quality and SF working dilution. Nonturbid SF samples, commonly collected in artificial insemination centers (AICs), were required. Compared with serum, SF testing had a decreased sensitivity in two of the ELISA assays (with original serum working dilutions Asunto(s)
Ensayo de Inmunoadsorción Enzimática/métodos
, Enfermedades de las Cabras/diagnóstico
, Infecciones por Lentivirus/veterinaria
, Semen/virología
, Enfermedades de las Ovejas/diagnóstico
, Animales
, Enfermedades de las Cabras/virología
, Cabras
, Infecciones por Lentivirus/diagnóstico
, Lentivirus Ovinos-Caprinos/genética
, Lentivirus Ovinos-Caprinos/aislamiento & purificación
, Estudios Longitudinales
, Masculino
, Sensibilidad y Especificidad
, Ovinos
, Enfermedades de las Ovejas/virología
RESUMEN
RNA transcripts of the B7 family molecule (CD80) are diminished in blood leukocytes from animals clinically affected with Visna/Maedi virus (VMV) infection. This work investigates whether the use of B7 genes enhances immune responses and protection in immunization-challenge approaches. Sheep were primed by particle-mediated epidermal bombardment with VMV gag and env gene recombinant plasmids together with plasmids encoding both CD80 and CD86 or CD80 alone, boosted with gag and env gene recombinant modified vaccinia Ankara virus and challenged intratracheally with VMV. Immunization in the presence of one or both of the B7 genes resulted in CD4+ T cell activation and antibody production (before and after challenge, respectively), but only immunization with CD80 and CD86 genes together, and not CD80 alone, resulted in a reduced number of infected animals and increased early transient cytotoxic T lymphocytes (CTL) responses. Post-mortem analysis showed an immune activation of lymphoid tissue in challenge-target organs in those animals that had received B7 genes compared to unvaccinated animals. Thus, the inclusion of B7 genes helped to enhance early cellular responses and protection (diminished proportion of infected animals) against VMV infection.
Asunto(s)
Adyuvantes Inmunológicos/administración & dosificación , Antígeno B7-1/administración & dosificación , Neumonía Intersticial Progresiva de los Ovinos/prevención & control , Vacunas de ADN/inmunología , Vacunas Virales/inmunología , Virus Visna-Maedi/inmunología , Adyuvantes Inmunológicos/genética , Adyuvantes Inmunológicos/farmacología , Animales , Anticuerpos Antivirales/sangre , Antígeno B7-1/genética , Antígeno B7-1/farmacología , Antígeno B7-2/administración & dosificación , Antígeno B7-2/genética , Antígeno B7-2/farmacología , Linfocitos T CD4-Positivos/inmunología , Productos del Gen env/administración & dosificación , Productos del Gen env/genética , Productos del Gen gag/administración & dosificación , Productos del Gen gag/genética , Vectores Genéticos , Inmunización Secundaria/métodos , Masculino , Ovinos , Linfocitos T Citotóxicos/inmunología , Virus Vaccinia/genética , Virus Visna-Maedi/genéticaRESUMEN
Staphylococcus aureus vaccines based on bacterins surrounded by slime, surface polysaccharides coupled to protein carriers and polysaccharides embedded in liposomes administered together with non-biofilm bacterins confer protection against mastitis. However, it remains unknown whether protective antibodies are directed to slime-associated known exopolysaccharides and could be produced in the absence of bacterin immunizations. Here, a sheep mastitis vaccination study was carried out using bacterins, crude bacterial extracts or a purified exopolysaccharide from biofilm bacteria delivered in different vehicles. This polysaccharide reacted specifically with antibodies to poly-N-acetyl-beta-1,6-glucosamine (PNAG) and not with antibodies to other capsular antigens or bacterial components. Following intra-mammary challenge with biofilm-producing bacteria, antibody production against the polysaccharide, milk bacterial counts and mastitis lesions were determined. Bacterins from strong biofilm-producing bacteria triggered the highest production of antibodies to PNAG and conferred the highest protection against infection and mastitis, compared with weak biofilm-producing bacteria and non-cellular inocula. Thus, bacterins from strong biofilm bacteria, rather than purified polysaccharide, are proposed as a cost-efficient vaccination against S. aureus ruminant mastitis.
Asunto(s)
Formación de Anticuerpos , Biopelículas , Mastitis/prevención & control , Vacunas Estafilocócicas/uso terapéutico , Staphylococcus aureus/fisiología , beta-Glucanos/inmunología , Animales , Femenino , Glándulas Mamarias Animales/patología , Mastitis/etiología , Mastitis/patología , Leche/microbiología , Embarazo , Ovinos , Infecciones Estafilocócicas/complicaciones , Infecciones Estafilocócicas/inmunología , Infecciones Estafilocócicas/patología , Infecciones Estafilocócicas/prevención & control , Resultado del TratamientoRESUMEN
Small ruminant lentiviruses (SRLVs) cause different clinical forms of disease in sheep and goats. So far in Spain, Maedi visna virus-like (MVV-like) sequences have been found in both species, and the arthritic SRLV disease has never been found in sheep until a recent outbreak. Knowing that arthritis is common in goats, it was of interest to determine if the genetic type of the virus involved in the sheep arthritis outbreak was caprine arthritis encephalitis virus-like (CAEV-like) rather than MVV-like. Alignment and phylogenetic analyses on nucleotide and deduced amino acid sequences from SRLV of this outbreak, allowed a B2 genetic subgroup assignment of these SRLV, compatible with a correspondence between the virus genetic type and the disease form. Furthermore, an isolate was obtained from the arthritic outbreak, its full genome was CAEV-like but the pol integrase region was MVV-like. Although its LTR lacked a U3 repeat sequence and had a deletion in the R region, which has been proposed to reduce viral replication rate, its phenotype in sheep skin fibroblast cultures was rapid/high, thus it appeared to have adapted to sheep cells. This outbreak study represents the first report on CAEV-like genetic findings and complete genome analysis among Spanish small ruminants.
Asunto(s)
Artritis Infecciosa/veterinaria , Brotes de Enfermedades/veterinaria , Infecciones por Lentivirus/veterinaria , Lentivirus Ovinos-Caprinos/genética , Enfermedades de las Ovejas/virología , Animales , Artritis Infecciosa/genética , Artritis Infecciosa/virología , Secuencia de Bases , Plexo Coroideo/virología , Clonación Molecular , ADN Viral/genética , ADN Viral/aislamiento & purificación , Genoma Viral , Infecciones por Lentivirus/epidemiología , Lentivirus Ovinos-Caprinos/clasificación , Lentivirus Ovinos-Caprinos/aislamiento & purificación , Filogenia , Reacción en Cadena de la Polimerasa/métodos , ARN Viral/genética , Ovinos , España , Líquido Sinovial/virología , Membrana Sinovial/virología , Secuencias Repetidas Terminales/genética , Virus Visna-Maedi/clasificación , Virus Visna-Maedi/genética , Virus Visna-Maedi/aislamiento & purificaciónAsunto(s)
Anestésicos Disociativos/administración & dosificación , Anestésicos Intravenosos/administración & dosificación , Ketamina/administración & dosificación , Piperidinas/administración & dosificación , Timpanoplastia , Anestésicos Intravenosos/farmacocinética , Niño , Contraindicaciones , Humanos , Infusiones Intravenosas , Inyecciones Intravenosas , Masculino , Óxido Nitroso , Piperidinas/farmacocinética , RemifentaniloRESUMEN
To determine whether systemic immunization with plasmid DNA and virus vector against visna/maedi virus (VMV) would induce protective immune responses, sheep were immunized with VMV gag and/or env sequences using particle-mediated epidermal bombardment and injection of recombinant modified vaccinia Ankara. The results showed that immunization induced both humoral and cell-mediated responses prior to and after virus challenge. The vaccination protocol did not prevent infection, but immunization with the gag gene or a combination of gag and env genes resulted in significantly reduced provirus loads in blood and mediastinal lymph node, respectively. Provirus loads in lung and draining lymph node were unaffected, but p25 expression was undetectable in lungs of animals immunized with a combination of gag and env genes. Analysis of target tissues for lesions at post-mortem showed that immunization with the env gene caused a significant increase in lesion score, while the gag gene or a combination of gag and env genes had no effect. Inclusion of the ovine interferon-gamma gene in the initial priming mixture had minimal effect on immune responses, provirus load, or lesion development, although it resulted in a decreased p25 expression in the lung. The results thus show that systemic immunization with gag or a combination of gag and env genes reduces provirus load in blood and lymphoid tissue, respectively whereas env immunization has no effect on provirus load but increased lesion development.
Asunto(s)
Biolística , Genes env/genética , Genes gag/genética , Neumonía Intersticial Progresiva de los Ovinos/prevención & control , Vacunas de ADN , Virus Vaccinia/genética , Animales , Anticuerpos Antivirales/sangre , Epidermis/virología , Femenino , Genes env/inmunología , Genes gag/inmunología , Inmunización , Masculino , Neumonía Intersticial Progresiva de los Ovinos/virología , Provirus/aislamiento & purificación , Ovinos , Linfocitos T/inmunología , Vacunas de ADN/administración & dosificación , Vacunas de ADN/genética , Vacunas de ADN/inmunología , Virus Vaccinia/inmunología , Vacunas Virales/administración & dosificación , Vacunas Virales/genética , Vacunas Virales/inmunología , Virión/genética , Virión/inmunología , Virus Visna-MaediRESUMEN
Sheep were immunized against Visna/Maedi virus (VMV) gag and/or env genes via the nasopharynx-associated lymphoid tissue (NALT) and lung using polyethylenimine (PEI)-DNA complexes and modified vaccinia Ankara, and challenged with live virus via the lung. env immunization enhanced humoral responses prior to but not after VMV challenge. Systemic T cell proliferative and cytotoxic responses were generally low, with the responses following single gag gene immunization being significantly depressed after challenge. A transient reduction in provirus load in the blood early after challenge was observed following env immunization, whilst the gag gene either alone or in combination with env resulted in significantly elevated provirus loads in lung. However, despite this, a significant reduction in lesion score was observed in animals immunized with the single gag gene at post-mortem. Inclusion of IFN-gamma in the immunization mixture in general had no significant effects. The results thus showed that protective effects against VMV-induced lesions can be induced following respiratory immunization with the single gag gene, though this was accompanied by an increased pulmonary provirus load.
Asunto(s)
Productos del Gen env/inmunología , Productos del Gen pol/inmunología , Neumonía Intersticial Progresiva de los Ovinos/prevención & control , Vacunas de ADN/inmunología , Vacunas Virales/inmunología , Virus Visna-Maedi/inmunología , Animales , Anticuerpos Antivirales/sangre , Proliferación Celular , Pruebas Inmunológicas de Citotoxicidad , Femenino , Productos del Gen env/genética , Productos del Gen pol/genética , Vectores Genéticos , Leucocitos Mononucleares/inmunología , Pulmón/inmunología , Pulmón/patología , Pulmón/virología , Masculino , Nasofaringe/inmunología , Provirus/aislamiento & purificación , Índice de Severidad de la Enfermedad , Ovinos , Linfocitos T Citotóxicos/inmunología , Vacunas de ADN/administración & dosificación , Virus Vaccinia/genética , Carga Viral , Vacunas Virales/administración & dosificaciónRESUMEN
Small ruminant lentiviruses (SRLV) are widely spread in many countries, including Spain. However, little is known about the genetic characteristics of Spanish goat and sheep SRLV. In this study, segments from three genomic regions (pol, gag-p25 and LTR) were amplified using DNA isolated from three Spanish autochthonous sheep (one) and goats (two). Animals (one per flock) belonged to distantly located, single-species flocks (goat or sheep). Sequence analysis showed conservation of regions that are putatively relevant to viral survival. Sequences of Spanish goat and sheep SRLV were allocated into phylogenetic trees (phylograms) with known SRLV groups. The phylograms corresponding to the pol, gag-p25 and LTR regions analyzed presented a compatible topology. This showed that Spanish caprine and ovine SRLV sequences belonged to the A or D phylogenetic groups and were closer to sheep SRLV prototypes (A1 group) than to goat SRLV prototypes (B or C groups), according to the current classification [Shah, C., Boni, J., Huder, J.B., Vogt, H.R., Muhlherr, J., Zanoni, R., Miserez, R., Lutz, H., Schupbach, J., 2004a. Phylogenetic analysis and reclassification of caprine and ovine lentiviruses based on 104 new isolates: evidence for regular sheep-to-goat transmission and worldwide propagation through livestock trade. Virology 319 (1), 12-26]. It was not possible to amplify in the three genetic regions the expected fragment in additional Spanish caprine and ovine SRLV proviral DNA sequences with the PCR primers used. This suggests that there is heterogeneity at the primer binding site among Spanish SRLV sequences. It also illustrates the need to develop diagnostic tests that are sensitive in local breeds.
Asunto(s)
Virus de la Artritis-Encefalitis Caprina/genética , Infecciones por Lentivirus/epidemiología , Virus Visna-Maedi/genética , Visna/epidemiología , Secuencia de Aminoácidos , Animales , Productos del Gen gag/genética , Genes pol/genética , Genoma Viral , Cabras , Datos de Secuencia Molecular , Filogenia , Alineación de Secuencia , Ovinos , España/epidemiología , Secuencias Repetidas Terminales/genéticaRESUMEN
A recent large-scale experimental study showed that bottle-feeding ovine colostrum from seropositive ewes results in high MVV-seroconversion in lambs. In contrast, relatively few lambs that naturally suckled colostrum from seropositive dams seroconverted as a result of it. Furthermore, lambs fed uninfected bovine colostrum readily seroconverted when mixed with ovine-colostrum lambs indicating that horizontal MVV transmission between lambs was efficient. MVV-infection was further investigated in the same samples using two PCR tests targeting sequences in the long-terminal repeats (LTR) and POL MVV genes. PCR-tests confirmed previous serological findings. However, the LTR-PCR was more sensitive and allowed detecting infection earlier than the other tests, including 5-8% of new-born lambs from seropositive dams, providing more evidence that prenatal MVV-infection may be more important than considered. The degree of agreement between PCR and antibody tests in individual samples was low up to 6 months of age and moderate at 10 months-old. Nine percent of lambs were always PCR-negative but seroconverted and 19% of lambs were PCR-positive at least once and did not seroconvert. However, seroconversion was associated with increasing number of times lambs were PCR-positive and ovine colostrum-fed lambs were more frequently PCR-positive than other lambs. The significance of these findings in terms of MVV-infection, epidemiology and control is discussed.