PCP causes significant economic losses to the swine industry making necessary a rapid diagnosis of A. pleuropneumoniae infections in order to establish efficient control measures. In the present study a successful infection of pigs with Ap6 was carried out, lesions as well as clinical and microbiological features of the disease were observed in most of the inoculated animals from 24 hpi onwards. Clinical signs of infection were first detected at 6 hpi, and the disease was generalized to all infected pigs at the end of the study (72 hpi). Our results highlight that Ap6 is able to colonize the nasal epithelium in the early stages of the infection, which may allow both the transmission to other animals and the progression of the bacteria to the lower respiratory tract. Although our results might be over-interpreted by the intranasal inoculation of the bacteria, the high number of animals with Ap6-isolation from nasal swabs at 24 and 48 hpi points to nasal swabs as a sample of interest for the early diagnosis of the disease, but other data such as clinical signs observed in the pens and/or lesions detected in dead animals must be taken into account.