Porcine circovirus type 2 (PCV2) is a small, non-enveloped, circular, single stranded DNA virus of economic importance in the swine industry worldwide. The focus of this dissertation was to investigate different aspects of horizontal transmission including the use of serology to accurately detect infection, the infectivity and amount of PCV2 present in various secretions and excretions following experimental or natural PCV2 infection, the use of disinfectants in the prevention of PCV2 transmission on livestock trailers, the potential for spread of infectious PCV2 in spray-dried plasma, and evaluation of disinfection protocol of a swine facility following a natural PCV2 outbreak. Results of the first study indicated that evaluated ELISAs had area under the receiver operating curve values greater than 0.94, detected both anti-PCV2a and -2b antibodies with no differentiation, and did cross react with anti-PCV1 antibodies in infected animals. The second study determined that PCV2 exposure (natural or experimental) results in a chronic infection and PCV2 is shed in similar amounts by nasal, oral and fecal routes. In addition, PCV2 DNA present in excretions, secretions or on mechanical vectors is infectious to nayve pigs and therefore important for PCV2 transmission. The third study determined that although PCV2 DNA was detected on trailer surfaces by PCR following three different disinfection protocols, PCV2 was not transmitted to nayve animals exposed to the contaminated trailers. The fourth study provided direct evidence that an experimental spray-drying process was not effective in inactivating PCV2 and it is therefore possible that spray-dried porcine plasma from pigs could represent a biosecurity risk for the industry. The final study showed that the combination of a multistep disinfection protocol with an improved, strict biosecurity plan can result in establishment of a PCV2 nayve herd and this status can be maintained for up to 10 months (300 days).