Sus scrofa scrofa, the most common and invasive Eurasian subspecies of wild boar, is the wild ancestor of domestic pig (Sus scrofa domestica), with which it shares close genetic affinity and susceptibility to most pathogens, including influenza viruses. Although much is known about the occurrence of influenza A virus infection in domestic swine herds, there is little information concerning the virus circulation in wild boar populations. During the periods May 2002-July 2003 and April 2010-April 2011, 741 serum samples were collected from free-living wild boars, captured in the Gessi Bolognesi Regional-Park (48.15 km2 area, located in the Emilia-Romagna Region, Northern Italy). Animals were categorised in 3 age classes: 1st class, <7 months; 2nd class, 7-14 months; 3rd class, >14 months. Two-fold serial dilutions of sera were tested for the presence of antibodies against influenza A nucleoprotein by a standard ELISA technique. Antibody titres of 1:8 or more were considered positive. The highest overall seroprevalence was found in the second period: 1.8% (9/502) in 2002-2003 vs. 18.8% (45/239) in 2010-2011. Likewise, age class-based seroprevalences showed higher values in the 2010-2011 period: 1st class, 2.3% (6/263) vs. 24.7% (20/81); 2nd class, 0.8% (1/132) vs. 11.1% (6/54); 3rd class, 1.9% (2/107) vs. 18.3% (19/104). Nine seropositive subjects were characterised by 1:8 titre in the first period, whereas in the second one the following seropositive frequencies were detected: n. 25 (1:8), n. 12 (1:16), n. 6 (1:32), n. 1 (1:64), n. 1 (1:128). Serologic data show an increased circulation of influenza A viruses in the second study period, despite a demographic control program has reduced population density in the area from about 13.5 wild boars/km2 (2002-2003) to about 7.3 wild boars/km2 (2010-2011). Although data from the end of 2003 to mid 2010 are missing, the higher antibody prevalences found in the second period in all age classes, could be the consequence of a new virus introduction in the study area. Infected wild boars could contribute to maintenance of the viral transmission cycle in natural habitats, thus representing a potential threat not only to humans involved in game and wildlife management programs but also to other wild and domestic susceptible species.
Antibodies to influenza A virus in European wild boars (Sus scrofa scrofa) from Northern Italy
DE MARCO, MARIA ALESSANDRA;COTTI, CLAUDIA;C. Musto;DELOGU, MAURO
2011
Abstract
Sus scrofa scrofa, the most common and invasive Eurasian subspecies of wild boar, is the wild ancestor of domestic pig (Sus scrofa domestica), with which it shares close genetic affinity and susceptibility to most pathogens, including influenza viruses. Although much is known about the occurrence of influenza A virus infection in domestic swine herds, there is little information concerning the virus circulation in wild boar populations. During the periods May 2002-July 2003 and April 2010-April 2011, 741 serum samples were collected from free-living wild boars, captured in the Gessi Bolognesi Regional-Park (48.15 km2 area, located in the Emilia-Romagna Region, Northern Italy). Animals were categorised in 3 age classes: 1st class, <7 months; 2nd class, 7-14 months; 3rd class, >14 months. Two-fold serial dilutions of sera were tested for the presence of antibodies against influenza A nucleoprotein by a standard ELISA technique. Antibody titres of 1:8 or more were considered positive. The highest overall seroprevalence was found in the second period: 1.8% (9/502) in 2002-2003 vs. 18.8% (45/239) in 2010-2011. Likewise, age class-based seroprevalences showed higher values in the 2010-2011 period: 1st class, 2.3% (6/263) vs. 24.7% (20/81); 2nd class, 0.8% (1/132) vs. 11.1% (6/54); 3rd class, 1.9% (2/107) vs. 18.3% (19/104). Nine seropositive subjects were characterised by 1:8 titre in the first period, whereas in the second one the following seropositive frequencies were detected: n. 25 (1:8), n. 12 (1:16), n. 6 (1:32), n. 1 (1:64), n. 1 (1:128). Serologic data show an increased circulation of influenza A viruses in the second study period, despite a demographic control program has reduced population density in the area from about 13.5 wild boars/km2 (2002-2003) to about 7.3 wild boars/km2 (2010-2011). Although data from the end of 2003 to mid 2010 are missing, the higher antibody prevalences found in the second period in all age classes, could be the consequence of a new virus introduction in the study area. Infected wild boars could contribute to maintenance of the viral transmission cycle in natural habitats, thus representing a potential threat not only to humans involved in game and wildlife management programs but also to other wild and domestic susceptible species.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
