Epidemiology of a Salmonella enterica subsp. enterica Serovar Typhimurium Strain Associated with a Songbird Outbreak

Abstract

h Salmonella enterica subsp. enterica serovar Typhimurium is responsible for the majority of salmonellosis cases worldwide. This Salmonella serovar is also responsible for die-offs in songbird populations. In 2009, there was an S. Typhimurium epizootic reported in pine siskins in the eastern United States. At the time, there was also a human outbreak with this serovar that was associated with contaminated peanuts. As peanuts are also used in wild-bird food, it was hypothesized that the pine siskin epizootic was related to this human outbreak. A comparison of songbird and human S. Typhimurium pulsed-field gel electrophoresis (PFGE) patterns revealed that the epizootic was attributed not to the peanut-associated strain but, rather, to a songbird strain first characterized from an American goldfinch in 1998. This same S. Typhimurium strain (PFGE type A3) was also identified in the PulseNet USA database, accounting for 137 of 77,941 total S. Typhimurium PFGE entries. A second molecular typing method, multiple-locus variable-number tandem-repeat analysis (MLVA), confirmed that the same strain was responsible for the pine siskin epizootic in the eastern United States but was distinct from a genetically related strain isolated from pine siskins in Minnesota. The pine siskin A3 strain was first encountered in May 2008 in an American goldfinch and later in a northern cardinal at the start of the pine siskin epizootic. MLVA also confirmed the clonal nature of S. Typhimurium in songbirds and established that the pine siskin epizootic strain was unique to the finch family. For 2009, the distribution of PFGE type A3 in passerines and humans mirrored the highest population density of pine siskins for the East Coast.

Evaluation of microbial contamination of feces and soil on a laying-hen farm depending on sampling site and season

“…Salmonella, especially S. Typhimurium, acquired directly from birds, animals or products of animal origin, can constitute a risk factor for human food poisoning and infection (Sanchez et al, 2002;Foley et al, 2008;Hoelzer et al, 2011;Hernandez et al, 2012).…”

Salmonella spp. as a cause of mortality and clinical symptoms in free-living garden bird species in Poland

“…Supplemental feeding creates high densities of birds, high concentrations of feaces and stress owing to social interactions what also leads to an increasing in some bacterial species prevalence within wild birds populations (Hamer et al 2011). Hernandez et al (2012) hypothesized that the pine siskin epizootic of Salmonella Typhimurium infection in USA was related to human outbreaks at the same time in similar regions, because of feeding the birds with peanuts that were eaten also by people.…”

“…The morbidity and mortality varies considerably and deaths, only in some exceptional cases, may approach 100% (Lister and Barrow 2008). Among free-living birds, the songbirds are considered to be much more sensitive for salmonellosis than other groups of birds (Hernandez et al 2012). …”

Importance of Wild Species Kept in Captivity as Reservoirs of Salmonella Serotypes for Human in Petting Exhibitions and Zoo in Iran with Focus on Antimicrobial Resistance

“…Enteritidis and 40.6% Typhimurium) and according to the Centers for Disease Control and Prevention (CDC), Salmonella serovars Typhimurium and Enteritidis are the two most common serovars associated with human disease, therefore, occurrence of these strains in zoo and pet species in Semnan represents a potential threat to public health (4,28). In some developed countries like the United States and in other areas of the world, Salmonella serovar Typhimurium is the second most commonly reported serotype causing salmonellosis in humans and the major cause of salmonellosis in wild birds with high mortality among infected birds (29)(30)(31). This data suggest the high importance of this serotype in animals mortality kept in captivity in Semnan, especially birds.…”