Selection of method is crucial for the diagnosis of porcine circovirus type 2 associated reproductive failures.

During a 2-month period a newly repopulated Danish pig herd experienced an increase in numbers of stillborn and mummies, caused by porcine circovirus type 2 (PCV2) associated reproductive failure. Based on recordings of data over time, the progression of the clinical outbreak was studied and the diagnostic value of different techniques was evaluated. Foetal hearts (38 cases and 13 controls) were examined by immunohistochemistry (IHC) and real-time polymerase chain reaction (PCR) for the detection of PCV2; and total immunoglobulin G (IgG) was measured in pleura cavity fluid. PCV2 IHC was positive in 14/38 of the case foetuses, which were delivered during a 9 days period early in the outbreak. On the basis of the results obtained by IHC and PCR, the foetuses were divided into 3 categories: PCV2 negative; moderately positive (10(4) to 10(7) copies per 500 ng DNA); and massively positive for PCV2 (>10(7) copies per 500 ng DNA). All control- and IHC positive foetuses were included in the negative and massively positive groups, respectively. Ten case foetuses had elevated IgG levels, which did not correlate with the IHC or PCR results. Based on the clustering of the IHC positive foetuses, it is suggested that IHC only is suited for diagnosing acute stages of reproductive failure, whereas quantitative PCR can be used as a sensitive diagnostic method within a wider time span. It seems that IgG measurements are unpredictable as indication of intrauterine infection with PCV2.

Juvenile kyphosis in pigs. A spontaneous model of Scheuermann's kyphosis.

The development of kyphotic lesions in pigs with different weights from herds with a high frequency of the lesion was analysed pathologically, radiologically, and for alkaline phosphatase, calcium, magnesium, and phosphate in blood samples. The development of kyphosis was caused by the formation of ventral hemivertebrae due to the absence of ventral vertebral epiphyseal centres of ossification. Within the ventral parts of affected vertebral epiphyses, the retained chondroid tissue was dysplastic and the contents of cartilage canals with vessels often clotted with fibrin were reduced. As lesions such as fractures and inflammation that may be a secondary cause of kyphosis in pigs were absent and all blood parameters were within normal range, secondary causes of the condition, including metabolic disturbances, were excluded. It can be seen that the present type of porcine kyphosis does not develop until later in life as the ossification centres within the epiphyses of vertebrae have a retarded appearance. As the present porcine type of kyphosis pathomorphologically is comparable with Scheuermann's kyphosis in man, it constitutes a spontaneous model for this common cause of structural kyphosis of the thoracic or thoracolumbar spine.