Uso do plasma suíno ultrafiltrado na recuperação de leitões com sinais clínicos de circovirose / The use of ultra-filtered swine plasma in the recovery of pigs with clinical signs of porcine circovirus infection

Testou-se o efeito do plasma suíno ultrafiltrado spray-dried, associado a um acidificante comercial na água de bebida para a recuperação de leitões com sinais clínicos da síndrome multissistêmica do definhamento dos suínos (SMDS). Utilizaram-se 40 leitões com sinais clínicos da SMDS, selecionados 20 dias após o alojamento em uma unidade de terminação, distribuídos em quatro tratamentos (T) de 10 leitões cada. No T1, os animais receberam água clorada à vontade (controle); no T2, solução com 2,5 por cento do plasma sangüíneo diluído em água; no T3, acidificante (Selko®) diluído em água na dosagem de 12ml/10l e, no T4, solução com 2,5 por cento do plasma sangüíneo e o acidificante na dose de 12ml/10l, diluídos em água. Os leitões não foram medicados e foram sacrificados aos 28 ou 40 dias de experimento para avaliação sorológica e patológica. Não houve diferença no ganho de peso e na situação clínica-patológica entre os tratamentos. Entretanto, os leitões do T4 estavam em melhor situação clínica-patológica. Os leitões dos quatro tratamentos tiveram boa recuperação, sem terem sido medicados. Observou-se alta freqüência de lesões compatíveis com a SMDS nos pulmões, rins e linfonodos. Concluiu-se que o plasma spray dried associado ao ácido não melhoraram o desempenho e a situação clínica-patológica de leitões com sintomas da SMDS

The effect of the ultra-filtered spray-dried porcine plasma, associated to a commercial acid in the drinking water was tested for recovering pigs with clinical signs of the porcine postweaning multisystemic wasting syndrome (PMWS). Forty piglets with clinical signs of the PMWS were used following a selection at 20 days after their housing in one finishing facility. They were divided in four treatment groups (T) of 10 pigs each: T1 - chlorine treated water ad libitum (control); T2 - solution prepared with 2.5 percent of plasma diluted in water; T3 - acid (Selko® ) diluted in water at the concentration of 12 ml/10l; T4 - solution prepared with 2.5 percent of plasma diluted and the acid (Selko® ) diluted in water at the concentration of 12 ml/10l. The pigs received no medication and were euthanized at 28 or 40 days after the beginning of the experiment for serological and pathological tests. Differences at the weight gain and in the clinical-pathological situation were not observed among the treatments. However, pigs from T4 were in better clinical-pathological situation. The pigs of all four treatments showed a good recovery, although they were not medicated. Even though, it was observed a high frequency of lesions compatible to PMWS in the lungs, kidneys and lymph nodes. It was concluded that the plasma spray-dried associated to the acid did not improve the performance and the clinical-pathological situation of pigs with clinical signs of PMWS

Spatiotemporal patterns and risks of herd breakdowns in pigs with postweaning multisystemic wasting syndrome.

A retrospective cohort study of 116 British pig farms was undertaken to investigate the epidemiological risk factors associated with herd breakdowns with postweaning multisystemic wasting syndrome (PMWS). Farmers reported the PMWS status of their herd (case definition 1) and, where applicable, when the disease was first suspected and what they observed; they described a prolonged increase in mortality in six to 16-week-old pigs that was not attributable to any disease known to be on their farm. There was over 90 per cent agreement on the farmers' PMWS status between the farmers and their veterinarians. Approximately 70 per cent of the breakdowns were confirmed at the laboratory (case definition 2) except during the outbreak of foot-and-mouth disease (FMD) in 2001 when it was reduced to 30 per cent. Porcine circovirus type 2 antigen was detected in pigs examined postmortem (case definition 3) in approximately 90 per cent of the farms with increased mortality. The breakdowns occurred initially in the south of England and spread west and north, as well as locally in a radial pattern from the affected farms, and there was strong statistical evidence that there was non-random space-time clustering. The risk of herd breakdowns with PMWS was not constant; therefore, for each case definition, three survival models were developed with outcome variable time to breakdown of between January 2000 and January 2001, February 2001 to September 2001 (during FMD) or October 2001 to December 2003. Exposures with a bivariable significance of P<0.20 were tested in three multivariable Cox proportional hazard models. From January 2000 to January 2001 the risk of a herd breakdown with PMWS for definitions 1, 2 and 3 was greater for farms with 600 or more breeding sows, and for definitions 1 and 3 there was an increased risk associated with the purchase of replacement gilts rather than using homebred replacements. For definitions 1 and 3 the farms where the nearest pig farm had no breeding pigs were at greater risk of a breakdown than those where the nearest farm had breeding stock, as were the farms where visitors were not requested to avoid pigs for more than three days before visiting the farm during the FMD outbreak. From October 2001, the associated risks were identical for all three case definitions; farms were at greater risk when they had 600 or more breeding sows, if visitors had not avoided contact with pigs for more than three days before visiting the farm, and when there was a farm with PMWS less than five miles away. The affected farms were more likely to have disease associated with porcine parvovirus, porcine reproduction and respiratory syndrome virus, erysipelas, Escherichia coli and salmonella. These exposures were positively associated with large herds and the farm being close to other pig farms, but did not remain in the final models for breakdown with PMWS, indicating that such farms may be at greater risk of many infectious diseases.

Postweaning multisystemic wasting syndrome (PMWS) in Sweden from an exotic to an endemic disease.

Postweaning multisystemic wasting syndrome (PMWS) is causally associated with porcine circovirus type 2 (PCV2) infection of pigs. PCV2 was first demonstrated in Swedish pigs in 1993, although the virus was almost certainly present in pigs in the country before that. Despite this, no signs of PMWS were observed in pigs of Sweden until the first outbreak was reported in 2003. The accumulated number of PMWS-affected herds have increased via 16 (2004) and 41 (2005) to 123 in December 2006. Of these herds, 30 (25%) have now been declared free from PMWS. However, a number of other herds have had individual pigs that have fulfilled the demands for PMWS at necropsy and 52 of these herds have been declared negative on herd basis after treatment for intestinal or respiratory diseases, and/or by correcting shortcomings in management of the herd including feed. Thus, individual cases of the disease have been observed in around 200 herds by the end of 2006 and PMWS is now regarded as an endemic disease in Sweden. The pig population of Sweden is geographically isolated, the density of pigs and the pathogen load in the country is low and the use of growth promoters (low dose antibiotics in feed) was prohibited in 1986. Additionally, the trade of animals in Sweden is organised in a restricted way. Because of these factors it is possible to conduct meaningful real-time studies on the transformation of PMWS in Sweden from being an exotic to an endemic disease in a three year time scale. Initially the PMWS cases were concentrated in the southern part of Sweden, but have gradually spread north. The PMWS-positive herds have, in general, had an effective production, but some management errors have constantly been observed in affected herds. Physical links between affected herds are often missing, and the data generated to date on the PMWS outbreaks in Sweden do not suggest an introduction of a new contagious microbe into the country that is responsible for the PMWS outbreaks, nor does PMWS appear to be spread via semen. In Sweden, intensity in rearing, disease preventing measures and immaturity of the piglets appear to be important as predisposing factors to PMWS and, as such, are discussed in this article.