Body condition is negatively associated with infection with Syngamus trachea in the ring-necked pheasant (Phasianus colchicus)

Abstract

Body condition is negatively associated with infection withNorth Somerset, BS40 5DU. 7 Summary 8The role that parasites play in regulating animal populations is debated, however recent research hints 9 at their pervasiveness among free-living animal populations. Parasites exert both direct and indirect 10 effects on host populations, and can act to regulate populations. The Ring-necked pheasant is an 11 important game-bird species in the UK, and large numbers of birds are released annually. The impact 12 of the ubiquitous tracheal nematode, Syngamus trachea on pheasant populations through effects on 13 host condition was assessed on two pheasant estates in the south west of England. Pheasants infected 14 with S. trachea demonstrated a significant reduction in host condition compared with uninfected 15 controls, with as few as one pair of worms per bird. Although there was no difference in worm 16 burden between sexes, analysis of regression slopes revealed there was a significant difference 17 between sexes in the magnitude of the effect of increasing worm burden on host condition, with 18 detectable effects observed in hosts with one and three pairs of worms for males and females 19 respectively. The observed reductions in host condition in birds with even sub-clinical infections 20 could be the cause of poor reproductive success and survival of pheasants post-release. 21

Syngamus asphyxiation in a captive ring-necked pheasant

“…In the United States, ring-necked pheasants are commonly raised in captivity for conservation stocking efforts or hunting, which makes them particularly susceptible to S. trachea infection. Infection with as few as one pair of S. trachea resulted in reduced body condition in pheasants (Gethings et al, 2016). Although it is extra-label, fenbendazole has been demonstrated to be both safe and efficacious as a treatment for S. trachea infections in pheasants (Griffith et al, 2014).…”

“…This aspect of the lifecycle can result in tracheitis and anemia in parasitized birds. Pheasants and other upland gamebirds appear to be especially susceptible to infection; and even low worm burdens can result in poor body condition, with heavy infections capable of causing death (Gethings et al, 2016).…”

Why do many pheasants released in the UK die, and how can we best reduce their natural mortality?

“…The effect of disease Reared pheasants are commonly at risk from pathogens and parasites including Heterakis gallinarum, Eucoleus contortus and Syngamus trachea (Draycott and Parish 2000;Lund and Chute 1974;Millán et al 2002). These pathogens and parasites can cause weight loss and significant mortality in heavily infected released pheasants (Gethings et al 2016;Ruff 1999). Attributing death to disease, as distinct from, e.g.…”

Parasitism by Syngamus trachea in Blue-and-Yellow Macaw (Ara ararauna)

“…The reduction in body condition score found in the A. ararauna, was also found in a Phasianus colchicus, with positive correlation between parasitism by S. trachea and body condition loss [8]. Thus, the body condition loss found in the blue-and-yellow macaw may be connected to the lowering of its feed conversion and food consumption.…”

“…Syngamosis has been reported in Galliformes [7,8,12] and raptors, however, the description of parasitosis in Psittacidae species is not found. Thus, the objective of this work was to report an occurrence of Syngamus trachea in Ara ararauna.…”