Implementation of immunohistochemistry on frozen ear notch tissue samples in diagnosis of bovine viral diarrhea virus in persistently infected cattle.

BACKGROUND: Bovine viral diarrhea is a contagious disease of domestic and wild ruminants and one of the most economically important diseases in cattle. Bovine viral diarrhea virus belongs to the genus Pestivirus, within the family Flaviviridae. The identification and elimination of the persistently infected animals from herds is the initial step in the control and eradication programs. It is therefore necessary to have reliable methods for diagnosis of bovine viral diarrhea virus. One of those methods is immunohistochemistry. Immunohistochemistry on formalin fixed, paraffin embedded tissue is a routine technique in diagnosis of persistently infected cattle from ear notch tissue samples. However, such technique is inappropriate due to complicated tissue fixation process and it requires more days for preparation. On the contrary, immunohistochemistry on frozen tissue was usually applied on organs from dead animals. In this paper, for the first time, the imunohistochemistry on frozen ear notch tissue samples was described. FINDINGS: Seventeen ear notch tissue samples were obtained during the period 2008-2009 from persistently infected cattle. Samples were fixed in liquid nitrogen and stored on -20°C until testing. Ear notch tissue samples from all persistently infected cattle showed positive results with good section quality and possibility to determinate type of infected cells. CONCLUSIONS: Although the number of samples was limited, this study indicated that immunohistochemistry on formalin fixed paraffin embedded tissue can be successfully replaced with immunohistochemistry on frozen ear notch tissue samples in diagnosis of persistently infected cattle.

Prevalence of antibodies to porcine parvovirus in wild boars (Sus scrofa) in Croatia.

Serologic evidence of exposure to porcine parvovirus (PPV) in the wild boar (Sus scrofa) in Croatia was investigated. Serum samples from 219 wild boars captured during 2003 from 12 different locations in the Republic of Croatia were tested by using a commercial enzyme-linked immunoassay (ELISA) and a hemagglutination inhibition (HI) test. Antibodies to PPV were detected in 91 (41.6%) of tested samples and positive results were detected in wild boar from all sample locations. Adults had a significantly higher prevalence (70%) than juveniles (31%; P < 0.01). Our results indicate that wild boar populations throughout the Republic of Croatia are exposed to PPV.