Diagnostic problems which can not be resolved with indirect serological methods used to be cleared by using two classical methods for direct detection of viral infection: p24 viral antigen assay or HIV culture.

The enzyme immunoassay was used for demonstration of specific viral antibodies, and the polymerase chain reaction for direct detection of viral genome.

Current routine diagnosis of human immunodeficiency virus (HIV) infection is based on the detection of specific antiviral antibodies in body fluids, mainly serum samples.

(d) Presence of sequence corresponding to that of ISAV segment 8 is evidence that the sample contained ISAV RNA.

(c) reasonable evidence of the presence of ISAV from two independent laboratory tests such as RT-PCR (Part IV) and IFAT (Part V);

The discriminatory test is designed to verify the presence or absence of classical swine fever virus circulation on a pig population vaccinated with a marker vaccine.

The HAD technique is recommended for the identification of ASF virus isolates due to its high sensitivity and specificity. HAD is based on the capability of the ASF virus to replicate in pig macrophages and induce haemadsorption in the presence of pig erythrocytes. A characteristic `rosette` of erythrocytes develops around the infected macrophages. However, a small number of field ASF virus strains may not induce haemadsorption, but they produce a cytopathic effect. These strains may be specifically identified using the DIF test on the sediments of the cell cultures or by PCR.

Viral antigens can be also detected using ELISA techniques, but it is only recommended for acute forms of the disease because of its low sensitivity when antigen-antibody complexes are present. The sensitivity of the antigen ELISA should be high enough to score a positive result from animals showing clinical signs of acute ASF. In any case it is recommended to use this test only as a `herd` test and in conjunction with other virological tests.

These laboratories shall not carry out virus detection in samples taken from suspect cases of vesicular diseases.

The preferred method to show the presence of influenza A virus is to demonstrate the possession of the nucleocapsid or matrix antigens which are shared by all influenza A virus.

Presence of sequence corresponding to that of ISAV segment 8 is evidence that the sample contained ISAV RNA.

an ELISA test or a serum neutralisation test for the presence of classical swine fever.

reasonable evidence of the presence of ISAV from two independent laboratory tests such as RT-PCR (Part IV) and IFAT (Part V);

Viral antigens can be also detected using ELISA techniques, but it is only recommended for acute forms of the disease because of its low sensitivity when antigen-antibody complexes are present.

poultry suspected of being infected shall mean any poultry showing clinical signs or post-mortem lesions which are such that the presence of avian influenza may reasonably be suspected or any poultry in which the presence of influenza A virus of subtype H5 or H7 has been demonstrated;

not earlier than 28 days after the last re-introduction, all animals must be clinically examined and samples for testing for the presence of antibody against foot-and-mouth disease virus shall be taken in accordance with the requirements of point 2.2 of Annex III;

any holding, after having obtained a negative result in a serological test for the detection of antibody against the foot-and-mouth disease virus carried out on a sample of blood taken prior to dispatch from the holding of origin.

Treatment of adult patients with chronic hepatitis B associated with evidence of hepatitis B viral replication (presence of HBV-DNA and HBeAg), elevated alanine aminotransferase (ALT) and histologically proven active liver inflammation and/or fibrosis.

Treatment of adult patients with chronic hepatitis B associated with evidence of hepatitis B viral replication (presence of HBV-DNA and HBeAg), elevated alanine aminotransferase (ALT) and t

have been isolated for at least 30 days immediately prior to loading and have undergone a serological test for the detection of antibody against foot-and-mouth disease virus structural proteins, carried out with negative results on samples taken during the 10 days prior to loading.

the animals intended for transport were either individually subjected with negative results to tests for the detection of antibodies against the foot-and-mouth disease virus at the end of the isolation period, or a serological survey was completed on that holding in accordance with point 2.2 of Annex III irrespective of the species concerned;

'Avian influenza' means an infection of poultry caused by any influenza A virus which has an intravenous pathogenicity index in six-week-old chickens greater than 1.2 or any infection with influenza A viruses of H5 or H7 subtype for which nucleotide sequencing has demonstrated the presence of multiple basic amino acids at the cleavage site of the haemagglutinin.

at least six months have elapsed since the last outbreak of foot-and-mouth disease or the completion of emergency vaccination, what ever event occurred later, and in accordance with the guidelines established in accordance with Article 70(3), a serological survey based on the detection of antibodies against non-structural proteins of the foot-and-mouth disease virus has demonstrated the absence of infection in vaccinated animals.