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E Albina

Publications and source records attributed to E Albina.

32 records · Page 2Linked to original sources
PubMed1998

Interferon-alpha response to swine arterivirus (PoAV), the porcine reproductive and respiratory syndrome virus.

We studied the interferon-alpha (IFN-alpha) system in relation to the porcine arterivirus (PoAV), porcine reproductive and respiratory syndrome virus (PRRSV). Recombinant porcine IFN-alpha inhibited the growth of this virus in alveolar macrophage cultures. When pigs were challenged intranasally with PoAV, their serum contained IFN-alpha in relatively low concentrations on the second day after challenge and up to 5 days at the latest. Most animals had no IFN-alpha in their lung secretions, even though PoAV replicates in the respiratory tract. In vitro, PoAV replicates in alveolar macrophages, but neither these nor peripheral blood mononuclear cells (PBMC) produced IFN-alpha in response to infection. This may be because PoAV suppresses IFN-alpha production. When macrophages treated with PoAV were superinfected with swine transmissible gastroenteritis virus (TGEV), a known good inducer of IFN, no IFN-alpha was detected. This suppressive effect was lost when the virus was inactivated by UV light. Our results suggest that downregulation of IFN-alpha production may play an important part in enabling PoAV to replicate in cell cultures and in pigs.

Administration, Intranasal↗
PubMed1997

Development of a RT-PCR test coupled with a microplate colorimetric assay for the detection of a swine Arterivirus (PRRSV) in boar semen.

Transmission of porcine reproductive and respiratory syndrome virus (PRRSV) through boar semen has been demonstrated, stressing the need for a reliable semen PRRSV detection test. A diagnostic assay was developed based on amplification of the PRRSV RNA by reverse transcription and polymerase chain reaction (RT-PCR) followed by detection of the amplification products by hybridization and colorimetric assay in microwell plates. A highly reproducible and efficient method of viral RNA isolation from semen samples was set up. A combined RT-PCR procedure was performed, incorporating the use of uracil-N-glycosylase (UNG) in combination with dUTP instead of dTTP to prevent false positive results due to carry-over contamination. An RNA internal control was added during the RNA isolation procedure to detect false negative results. The colorimetric detection in microwell plates of amplification products from either PRRSV or IC RNA gave specific and objective results and was automated. A cut-off value of 1000 RNA copies or 10 TCID50 of PRRSV per ml of semen samples could be detected with this assay. Semen samples collected from experimentally-infected boars were tested with this assay and showed PRRSV excretion early after infection and for an extended period.

Animals↗
PubMed1997

Results of a control programme for the porcine reproductive and respiratory syndrome in the French 'Pays de la Loire' region.

The porcine reproductive and respiratory syndrome (PRRS) virus first entered the Pays de la Loire region in November 1992, with variable effects ranging from sub-clinical seroconversion to severe reproductive failure and piglet mortality, and significant reduction of daily weight gains in finishing pigs. An epidemiological survey was carried out in February 1993. Since the infection prevalence was low (11 infected out of 2310 herds), the pig population was of medium density and the eradication programme of Aujeszky's disease had been successful in the Pays de la Loire region, it was decided (in March 1993) to undertake a control programme for PRRS. In 1993, introduction of infected pigs was known to be the most frequent source by which PRRS virus entered a herd. In the absence of vaccination, this source of virus introduction was reduced by a control programme applied to all members of the regional pig industry, through the impetus of the leaders of the Regional Sanitary Defence Confederation (FRGDS). The control programme was applied on purchased animals (sows, boars, piglets), artificial insemination centres and other environmental factors (people, vehicles, materials, slurry,...). Moreover, pigs from many infected herds were slaughtered. Results showed that in a context of low prevalence and limited spreading to nearby herds, efficient control of animal movements limited the infection spread. At the end of 1993, the PRRS prevalence was 2.7% in the region. Two years after the first outbreak, the PRRS infection could be considered as controlled since 98% of the herds remained free. In order to maintain this low infected status, the control programme was renewed. From this study epidemiological investigations have raised two major initial sources of infection, the use of contaminated semen and the introduction of infected pigs. Around an infected herd, serological screening is still running to detect infection in nearby herds.

Animal Husbandry↗
PubMed1997

Epidemiology of porcine reproductive and respiratory syndrome (PRRS): an overview.

PRRS disease was first recognised in the USA in 1987 and in Europe in 1990 and since then the disease has spread widely throughout many pig-producing countries. After a severe epidemic phase, the infection has become endemic. The prevalence of infection is generally high in infected countries. However, in areas with a low density of pigs, infection may spread slowly and if infected animal movements are not significant, farm-to-farm spread can be controlled and prevalence of infection maintained at a low level. The PRRS virus (PRRSV) was completely unknown before 1986, and the question of its origin remains unanswered. The exact epidemiologic relationship between American and European strains of PRRSV is difficult to establish because different isolates appear to belong to two distinct sub-populations which are only distantly antigenically related. In the environment, virus survival is optimal when temperature is cold and when ultra-violet light exposure is low (little sunshine). These conditions are easily attained in winter and that may explain why virus spread increases during this period. Pigs of any age (including wild boars) are the only animals known to be naturally infected with PRRSV. Relatively close contact between pigs is the primary factor in virus transmission. Aerial transmission is a second mechanism of spread, particularly in winter and particularly over distances of less than 3 km. A third route of transmission is via semen. The role of fomites is not clearly documented, however since the virus is excreted in faeces and urine, slurry should be considered as a potential source of contamination. Within herds, the virus spreads rapidly with up to 85 to 95% of pigs in a herd becoming sero-positive within two to three months. Thereafter, virus activity persists for extended periods (several month to years). Nevertheless, some authors have reported spontaneous elimination of PRRSV from infected farms. For the future, there remain questions concerning the possible evolution of the disease (in terms of its sanitary and economic impacts), and the possible influence of vaccines on the epidemiological features of PRRS.

Animals↗
PubMed1994

Immune response and persistence of the porcine reproductive and respiratory syndrome virus in infected pigs and farm units.

The kinetics of the serum antibody response to porcine reproductive and respiratory syndrome (PRRS) virus and the persistence of the virus after infection were determined in experimentally and naturally infected pigs. In an experimental study, four specific pathogen free (SPF) sows were infected with a French strain of PRRS virus at 90 days of gestation, and their piglets (the test piglets) were monitored for 29 weeks from birth. In one litter, antibodies against PRRS virus were absent before the piglets had ingested colostrum. Four days after birth, passive antibodies were present in the serum of these piglets, but they had disappeared by three weeks (just before weaning) when clinical signs were observed in a minority of the pigs. In a second litter, most of the piglets had no detectable antibodies until they were four weeks old, and clinical signs were observed during their second week of life. By eight weeks, antibodies were detected in all the pigs, and they persisted until observations ceased at 29 weeks. Two groups of three SPF pigs were placed in direct contact with the test piglets when they were four weeks old and a group of five SPF pigs was placed in indirect contact when they were 13 weeks old. The first two groups showed clinical signs and seroconverted but the third group did not. At 22 weeks old, two of the test piglets were subjected to movement stress and were given exogenous corticosteroids, after which the in-contact SPF pigs developed clinical signs and seroconverted.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[Development and use of an immunoenzyme technique for the routine diagnosis of the porcine reproductive and respiratory syndrome].

An indirect enzyme-linked immunosorbent assay was developed for rapid detection of serum antibodies against the virus responsible for the porcine reproductive and respiratory syndrome (PRRS). This test is more sensitive than the reference technique (immunoperoxidase test applied to cultures of alveolar macrophages), particularly for detecting animals at the stage of seroconversion. It is also very specific for PRRS virus, because all specific hyperimmune sera against other porcine viruses, and all serum samples taken from herds before the disease appeared in western France were negative. The test has been used for routine diagnosis of PRRS. The results obtained during nine months from over 21,000 samples have confirmed the value of the test for diagnosis and epidemiological surveillance of the disease.

Abortion, Veterinary↗
PubMed1992

Report on the first outbreaks of the porcine reproductive and respiratory syndrome (PRRS) in France. Diagnosis and viral isolation.

We describe the first known occurrence in France of the porcine reproductive and respiratory syndrome (PRRS), a new porcine disease that first appeared in Germany in November 1990. Outbreaks of the disease appeared in November 1991 in Brittany (France), with comparable clinical features to those observed in other countries, were definitively confirmed by a serological analysis from the affected animals using an immunoperoxidase monolayer assay with PRRS-virus infected alveolar macrophages. Furthermore, we report the isolation from one serum of a filtrable agent that, in view of its cytopathic effect for porcine alveolar macrophages and of the serologic reactivity of the infected cells, appears similar to the Lelystad virus that has been implicated in the etiology of the disease.

Animals↗
PubMed1992

An enzyme linked immunosorbent assay (ELISA) for the detection of antibodies to the porcine reproductive and respiratory syndrome (PRRS) virus.

An indirect enzyme-linked immunosorbent assay (ELISA) has been developed for the rapid detection of antibodies to the porcine reproductive and respiratory syndrome (PRRS) virus in pig sera. Compared to the immunoperoxidase monolayer assay (IPMA) which was the only test available up till recently for serodiagnosis of the disease, the ELISA test proved to be more sensitive, particularly for early detection of antibodies. The test was also highly specific for the PRRS virus inasmuch as it scored negative all the hyperimmune sera directed to other swine viruses and the field sera sampled before the outbreak of the disease in Brittany (France). This easy test now provides further possibilities for epidemiological surveys and could also be a reliable tool for new sanitary prophylaxis of the disease.

Animals↗
PubMed1990

Action of guar gums on the viscosity of digestive contents and on the gastrointestinal motor function in pigs.

The apparent viscosity of three test meals containing 6% of different guar gums was measured in the gastric, duodenal and jejunal contents and related with the gastrointestinal myoelectric activity and transit time in pigs. The motility index (mV/min) and the spike burst frequency (number of spike bursts/min) were closely related to the digesta viscosity: they were significantly increased by most viscous contents in stomach and small intestine. This effect was associated with an increase in the orocecal transit time of liquids and solids.

Animals↗
PubMedDate not supplied

Antigenic variability of porcine reproductive and respiratory syndrome (PRRS) virus isolates. Influence of virus passage in pig.

In order to study the antigenic variability of porcine reproductive and respiratory syndrome virus (PRRSV), 18 European and Canadian field isolates were analysed with a panel of 15 monoclonal antibodies (MAbs) raised against five different European and one Canadian PRRSV isolates. The antigenic pattern of these isolates was used to infer their phylogenetic relationships. Isolates which had the same reactivity pattern were gathered together so that five antigenic profiles were analysed. The pairwise distances between these groups were defined based on antigenic pattern differences. Two main antigenic groups were obtained, discriminating between the European and the Canadian populations, as illustrated by the great distance observed between European and Canadian isolates (D = 0.5619 +/- 0.0625) compared to the distance between European isolates (D = 0.1524 +/- 0.0735). The distance matrix allowed also the construction of a tree diagram. Bootstrap analysis was performed to test the confidence in the branching. The tree diagram confirmed the distinction between the European and the Canadian PRRSV populations. Antigenic variability between an isolate and its progeny recovered after one or two passages in vivo was examined on six isolates. It was restricted to the GP3 protein of the virus.

Animals↗
PubMedDate not supplied

[Porcine reproductive and respiratory syndrome: ten years of experience (1986-1996) with this undesirable viral infection].

Porcine reproductive and respiratory syndrome (PRRS) is an infectious disease in swine that emerged 10 years ago. Today, PRRS is endemic in many if not all the pig-producing countries. The syndrome is due to a small enveloped RNA virus which belongs to the new Arteriviridae group. This group also includes the equine arterivirus and the simian hemorrhagic fever virus. The disease produces many clinical symptoms in pigs of any age but the two major features of the syndrome are respiratory and reproductive failure. An influenza-like illness is often observed consisting of a transient loss of appetite, slight hyperthermia and respiratory distress. The reproductive problems include late-term abortion, stillbirth and young piglet mortality. The virus is remarkably well adapted to its natural host. It infects almost exclusively pig monocytes or macrophages. For unexplained reasons, the virus may persist in the body for extended periods (several weeks) after an antibody immune response has been mounted. Within herds, the virus may persist for several years. In the acute phase of the infection, the immune functions of the pig may be impaired, however, a chronic immunosuppressive effect does not seem to occur thereafter. Several vaccines are available, which all have protective value against PRRS clinical disorders. None of them, however, has been tested for its ability to prevent or shorten the persistent infection in individual pigs or the long-term effect of virus circulation within herds. In the future, PRRS virus may be only an additional contaminant of farms with limited effects on profitability; however the possibility for this persistent infection to supply swine or eventually other species with new pathogenic variants must be also considered. This review provides a detailed description of the aetiology, pathology, immunology, diagnostic methods and epidemiology of PRRS.

Abortion, Veterinary↗