Potential for contact and mechanical vector transmission of vesicular stomatitis virus New Jersey in pigs

Objective-To determine whether swine could be infected with vesicular stoma titis virus New Jersey (VSV-NJ) by routes simulating mechanical vector and contact transmission, and to document clinical response and measure source, duration, and extent of associated viral shedding. Animals-48 approximately 10-kg male pigs. Procedure-7 inoculation routes were tested at 3 virus concentrations (10(6) , 10(4), and 10(2) median tissue culture-infective doses [TCID50]). Inocula tion routes included intradermal (snout), topical application of virus to a scarified area (ear or mucous membrane of the lip), mucosal (oral or conju nctiva) application, and nasal instillation (drop or aerosol). Swine were m onitored daily for clinical disease, seroconversion, and virus isolation. Results-Virus was isolated from swab specimens of nasal planum, nasal cavit y, saliva, tonsil, and feces from 15 pigs infected by intradermal snout ino culation (10(6) and 10(4) TCID50), scarification of the lip (10(6) and 10(4 ) TCID50), and oral route (10(6) TCID50). Virus was not isolated from plasm a. Vesicular lesions were restrict ed to pigs inoculated via intradermal sn out and lip scarification routes. Seroconversion was detected in 23 pigs in oculated by ail routes except intranasal aerosol and conjunctival. Frequenc y of virus isolation from these pigs was dependent on serologic status and presence of vesicular lesions. Conclusions-Viral titers obtained from swab specimens and infective doses i ndicated that sufficient virus is shed from infected swine for contact or m echanical transmission to occur. Amount of virus is highest when lesions ar e present and before seroconversion. Pigs may represent an effective targe- animal model for studying pathogenesis and transmission of VSV-NJ.