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Endoparasites in a Norwegian moose (Alces alces) population - Faunal diversity, abundance and body condition.

Davidson RK, Ličina T, Gorini L, Milner JM - Int J Parasitol Parasites Wildl (2015)

Bottom Line: We found no strong evidence for the development of acquired immunity to abomasal nematodes with age, although there was a higher Protostrongylid and Moniezia infection prevalence in younger animals.High burdens of several parasites were associated with poor body condition in terms of slaughter weight relative to skeletal size but unrelated to visually evaluated fat reserves.Given findings from earlier experimental studies, our results imply sub-clinical effects of GI parasite infection on host condition.

View Article: PubMed Central - PubMed

Affiliation: Norwegian Veterinary Institute, Pb 750 Sentrum, 0106 Oslo, Norway.

ABSTRACT
Many health surveillance programs for wild cervids do not include routine parasite screening despite evidence that gastrointestinal parasites can affect wildlife population dynamics by influencing host fecundity and survival. Slaughter weights of moose in some regions of Norway have been decreasing over recent decades but any role of parasites has not yet been considered. We investigated parasite faunal diversity of moose in Hedmark, SE Norway, by faecal analysis and identification of adult abomasal and caecal nematodes during the autumn hunting season. We related parasite prevalence and abundance to estimates of body condition, gender and age. We identified 11 parasite groups. Moose had high abomasal gastrointestinal nematode (GIN) burdens and all individuals were infected. Ostertagia antipini and Spiculopteragia alcis were the most prevalent abomasal GINs identified. O. leptospicularis and Telodorsagia circumcincta were also identified in the abomasa while a range of other GIN and Moniezia sp. eggs, and coccidia, Dictyocaulus sp. and Protostrongylid larvae were found in faeces. Female moose had higher mean abomasal nematode counts than males, particularly among adults. However, adult males had higher faecal egg counts than adult females which may reflect reduction in faecal volume with concentration of eggs among males during the rut. We found no strong evidence for the development of acquired immunity to abomasal nematodes with age, although there was a higher Protostrongylid and Moniezia infection prevalence in younger animals. High burdens of several parasites were associated with poor body condition in terms of slaughter weight relative to skeletal size but unrelated to visually evaluated fat reserves. Given findings from earlier experimental studies, our results imply sub-clinical effects of GI parasite infection on host condition. Managers should be aware that autumn faecal egg counts and field assessments of fat reserves may not be reliable indicators of parasitism and may underestimate impacts on wildlife populations.

No MeSH data available.


Related in: MedlinePlus

A box–whisker plot showing the prevalence of infection with protostrongylid larvae (dorsal spine larvae) in moose hunted during the licensed hunting season, autumn 2013, in Hedmark county, Norway, in relation to age. The median (solid black line), quartiles (ends of boxes) with the whiskers indicating the variability outside the quartiles, and extreme outliers, individual points, are shown.
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f0025: A box–whisker plot showing the prevalence of infection with protostrongylid larvae (dorsal spine larvae) in moose hunted during the licensed hunting season, autumn 2013, in Hedmark county, Norway, in relation to age. The median (solid black line), quartiles (ends of boxes) with the whiskers indicating the variability outside the quartiles, and extreme outliers, individual points, are shown.

Mentions: Larval output of DSL ranged from 1 to 85 LPG (mean 32, median 25 LPG) among positive animals (n = 9). Calves and poor condition individuals had significantly higher DSL infection probabilities than older and better condition animals (χ21,38 = 15.83, p < 0.001 and χ21,38 = 4.19, p = 0.041 respectively, Fig. 3). Males and light weight individuals had higher mean LPG than females and heavy animals (F1,36 = 15.56, p < 0.001 and F1,36 = 77.38, p < 0.001). No larvae of Dictyocaulus sp. were found in adult moose, suggesting an effect of age but this was not tested due to small sample size. Infected individuals also had poorer than average body condition but with only two yearlings and one calf infected, each with fewer than 3 LPG faeces, further investigation is needed.


Endoparasites in a Norwegian moose (Alces alces) population - Faunal diversity, abundance and body condition.

Davidson RK, Ličina T, Gorini L, Milner JM - Int J Parasitol Parasites Wildl (2015)

A box–whisker plot showing the prevalence of infection with protostrongylid larvae (dorsal spine larvae) in moose hunted during the licensed hunting season, autumn 2013, in Hedmark county, Norway, in relation to age. The median (solid black line), quartiles (ends of boxes) with the whiskers indicating the variability outside the quartiles, and extreme outliers, individual points, are shown.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4356740&req=5

f0025: A box–whisker plot showing the prevalence of infection with protostrongylid larvae (dorsal spine larvae) in moose hunted during the licensed hunting season, autumn 2013, in Hedmark county, Norway, in relation to age. The median (solid black line), quartiles (ends of boxes) with the whiskers indicating the variability outside the quartiles, and extreme outliers, individual points, are shown.
Mentions: Larval output of DSL ranged from 1 to 85 LPG (mean 32, median 25 LPG) among positive animals (n = 9). Calves and poor condition individuals had significantly higher DSL infection probabilities than older and better condition animals (χ21,38 = 15.83, p < 0.001 and χ21,38 = 4.19, p = 0.041 respectively, Fig. 3). Males and light weight individuals had higher mean LPG than females and heavy animals (F1,36 = 15.56, p < 0.001 and F1,36 = 77.38, p < 0.001). No larvae of Dictyocaulus sp. were found in adult moose, suggesting an effect of age but this was not tested due to small sample size. Infected individuals also had poorer than average body condition but with only two yearlings and one calf infected, each with fewer than 3 LPG faeces, further investigation is needed.

Bottom Line: We found no strong evidence for the development of acquired immunity to abomasal nematodes with age, although there was a higher Protostrongylid and Moniezia infection prevalence in younger animals.High burdens of several parasites were associated with poor body condition in terms of slaughter weight relative to skeletal size but unrelated to visually evaluated fat reserves.Given findings from earlier experimental studies, our results imply sub-clinical effects of GI parasite infection on host condition.

View Article: PubMed Central - PubMed

Affiliation: Norwegian Veterinary Institute, Pb 750 Sentrum, 0106 Oslo, Norway.

ABSTRACT
Many health surveillance programs for wild cervids do not include routine parasite screening despite evidence that gastrointestinal parasites can affect wildlife population dynamics by influencing host fecundity and survival. Slaughter weights of moose in some regions of Norway have been decreasing over recent decades but any role of parasites has not yet been considered. We investigated parasite faunal diversity of moose in Hedmark, SE Norway, by faecal analysis and identification of adult abomasal and caecal nematodes during the autumn hunting season. We related parasite prevalence and abundance to estimates of body condition, gender and age. We identified 11 parasite groups. Moose had high abomasal gastrointestinal nematode (GIN) burdens and all individuals were infected. Ostertagia antipini and Spiculopteragia alcis were the most prevalent abomasal GINs identified. O. leptospicularis and Telodorsagia circumcincta were also identified in the abomasa while a range of other GIN and Moniezia sp. eggs, and coccidia, Dictyocaulus sp. and Protostrongylid larvae were found in faeces. Female moose had higher mean abomasal nematode counts than males, particularly among adults. However, adult males had higher faecal egg counts than adult females which may reflect reduction in faecal volume with concentration of eggs among males during the rut. We found no strong evidence for the development of acquired immunity to abomasal nematodes with age, although there was a higher Protostrongylid and Moniezia infection prevalence in younger animals. High burdens of several parasites were associated with poor body condition in terms of slaughter weight relative to skeletal size but unrelated to visually evaluated fat reserves. Given findings from earlier experimental studies, our results imply sub-clinical effects of GI parasite infection on host condition. Managers should be aware that autumn faecal egg counts and field assessments of fat reserves may not be reliable indicators of parasitism and may underestimate impacts on wildlife populations.

No MeSH data available.


Related in: MedlinePlus