Detection and quantification of classical swine fever virus in air samples originating from infected pigs and experimentally produced aerosols

Abstract

During epidemics of classical swine fever (CSF), neighbourhood infections occurred where none of the 'traditional' routes of transmission like direct animal contact, swill feeding, transport contact or transmission by people could be identified. A hypothesized route of virus introduction for these herds was airborne transmission. In order to better understand this possible transmission route, we developed a method to detect and quantify classical swine fever virus (CSFV) in air samples using gelatine filters. The air samples were collected from CSFV-infected pigs after experimental aerosolization of the virus. Furthermore, we studied the viability of the virus with time in aerosolized state. Three strains of CSFV were aerosolized in an empty isolator and air samples were taken at different time intervals. The virus remained infective in aerosolized state for at least 30 min with half-life time values ranging from 4.5 to 15 min. During animal experiments, concentrations of 10 0.3 -10 1.6 TCID 50 / m 3 CSFV were detected in air samples originating from the air of the pig cages and 10 0.4 -10 4.0 TCID 50 /m 3 from the expired air of infected animals. This is the first study describing the isolation and quantification of CSFV from air samples originating from infected pigs and their cages, supporting previous findings that airborne transmission of CSF is feasible. #

Primary biological aerosol particles in the atmosphere: a review

“…Virus aerosols collected from the exhaled air of infected animals have been the subject of various research studies. For example, for pigs infected with classical swine fever virus, the concentration of viral particles may reach 10 4 m (3 of air (Weesendorp et al, 2008). Other infections of animals and birds (such as foot-and-mouth disease, Newcastle disease, etc.)…”

Airborne transmission of a highly pathogenic avian influenza virus strain H5N1 between groups of chickens quantified in an experimental setting

“…According to the manual of the manufacturer, samples were taken daily for 10', a protocol that 304 had also been used by Weesendorp et al (2008) to detect classical swine fever virus in 305 ambient air. Moreover, chickens are exposed to virus containing particles much longer, which 306 may have increased the probability of contracting the infection.…”

Influence of colostral antibodes on immunity of piglets vaccinated against classical swine fiver

“…Eksperimentalno je utvrđeno da psi, mačke i glodari (pacovi) nisu biološki rezervoari (22) ali je moguće mehaničko prenošenje virusa (93). Lovački psi u enzootski zaraženim regionima kontaktom sa krvi viremičnih divljih svinja mogu preneti virus pasivno na koži i krznu u ograničenom vremenskom periodu (72).…”

“…Infekcije iz susedstva su po definiciji sekundarna žarišta u zapatima lokalizovanim u neposrednoj blizini (1000 m) primarno inficiranog zapata pri nepoznatom putu infekcije (93). Infekcija iz susedstva ne predstavlja zaseban put i ubraja se u puteve prenošenja na malim udaljenostima (16).…”

“…Veličina zapata predstavlja faktor rizika i uvećanjem broja prijemčivih svinja, uvećava se verovatnoća infekcije dok ista opada uvećanjem razdaljine od primarno inficiranog zapata (98). Širenje infekcije se umanjuje radijalnim uvećanjem udaljenosti od primarno inficiranog zapata (93).…”