*3.2.3. Classical swine fever virus (CSFV)*

The virus of the classical swine fever belongs to Pestvirus genus. It is highly contagious and causes the classical swine fever (CSF), with mortality rates ranging from 80 to 90% and leads to a framework of generalized bleedings. The contact with wild animals and infected food and the transit of animals are the main forms for CSFV dissemination. Therefore, the mar‐ keting of semen for AI is considered an additional hazard [56].

In an experimental study, van Rijn et al [57] (2004) observed the presence of CSFV in pigs' semen at 3 days after infection. The elimination continued intermittently until the end of the experiment (18 days), as proving that artificial insemination can be a risk factor for transmis‐ sion of the disease.

Due to importance of the disease, the clinical suspicion should be investigated by laboratory techniques. While virus isolation is the gold standard, other tests such as ELISA and RT-PCR can be used for definitive diagnosis [58, 59]. The tonsils, spleen, pharyngeal and mesen‐ teric ganglions are the favorite organs for sending to laboratories.

In the case of diagnostic confirmation, several procedures should be taken in order to pre‐ vent the virus from spreading through the region. The sacrifice of the positive animals, the prohibition that animals and semen to transit in the region as well as the installation of sani‐ tary barriers are actions for controlling the outbreak. Another control procedure is vaccina‐ tion, however only attenuated alive vaccines are available, as hampering the differentiation between vaccinated and infected animals [60].
