Pathogen Presence in European Starlings Inhabiting Commercial Piggeries in South Australia

Abstract

The majority of bacterial diarrhea-causing illnesses in domestic pigs result from infection with Escherichia coli, Salmonella spp., or Campylobacter spp. These bacterial enteropathogens also correspond with the most-common bacteria isolated from wild birds. Additionally, viral pathogens such as avian influenza virus (AIV), West Nile virus (WNV, including Kunjin disease), and Newcastle disease virus (NDV) may also be carried and transmitted by birds in Australia. Introduced European starlings (Sturnus vulgarus) are one of the most-frequently reported birds on piggeries in Australia. The presence of the three bacterial pathogens, Salmonella spp., Campylobacter spp., and Escherichia coli , as well as the three viral pathogens AIV, WNV, and NDV, were evaluated in starlings captured on four commercial piggeries in South Australia. A total of 473 starlings were captured on the four piggeries in 2008 and 2009. A cloacal swab was taken from each bird and cultured for bacterial identification, with follow-up serotyping of any positives, whilst fifty samples were analyzed by PCR for the three target viral pathogens. There was no AIV, WNV, or NDV detected in the 50 starlings sampled. Escherichia coli was found to be present in the starling populations on all four piggeries whilst Salmonella spp. and Campylobacter jejuni were found to be present only in the starling population sampled on one piggery. Serotyping identified pig-pathogenic strains of the bacteria. The prevalence of these production-limiting bacterial pathogens in starlings, coupled with the large starling populations often found inside piggeries during daylight hours in the summer months, presents a disease transmission risk and jeopardizes piggery disease management. Removal of starlings from agricultural enterprises (as shown by international studies), or prevention of starling access to animal feed and water, could substantially reduce the risk of transmission of enterobacterial pathogens from starlings to livestock.

Avian influenza A virus susceptibility, infection, transmission, and antibody kinetics in European starlings

“…A number of field studies have provided evidence that wild caught European starlings can be naturally infected or exposed to IAVs [19,[25][26][27][28][29][30][31]. However, in aggregate these studies suggest that starlings are not frequently infected or exposed to IAVs [32][33][34]. The relatively low seroprevalence observed in these studies might be partially explained by the relative transience of detectable antibodies demonstrated in our study.…”

Wild Boar: A Reservoir of Foodborne Zoonoses

“…However, outdoor farming may increase due to public demand for more ethical and natural animal production and higher quality meat products (Jori et al, 2017, Murrell, 2016. Especially, pigs with outdoor access in areas of high-density wild boar populations should apply biosecurity practices to prevent contact between them and wild boars (Pearson et al, 2016).…”

European Starlings (Sturnus vulgaris) as Vectors and Reservoirs of Pathogens Affecting Humans and Domestic Livestock

“…In cattle, most strains are non-pathogenic but some cause economically important disease [12]; cows also carry strains pathogenic to humans. In pigs, some strains cause economically important disease [13]. To the extent that starlings can spread these bacteria among livestock, pets, or directly to humans, an interest in their role in disease dynamics is warranted.…”

“…A large variety of strains have been cultured or identified from European starlings. A study in Australia [13] identified 5 different strains from 6 individuals (S. enterica enterica serovar Kottbus, S. enterica enterica serovar Muenster, S. enterica enterica serovar Bredeney, S. enterica enterica serovar Anatum, S. enterica enterica serovar Oranienburg.) Carlson et al [31] identified 5 different strains from 100 individuals, and all strains were recovered both from gastrointestinal cultures and cultures made from external washes.…”

“…European starlings can be infected with West Nile Virus, though their importance in spreading the disease to humans is likely limited due to low competence as a reservoir species and feeding behavior of the mosquito vectors [66,67]. Few published studies of surveys with large sample size are available; sporadic reports suggest low seropositivity in wild starlings [13,[66][67][68][69]…”