Detection of anti-parelaphostrongylus tenuis antibodies in experimentally infected and free-ranging moose (Alces alces)

Confirming Parelaphostrongylus tenuis infection in moose (Alces alces) and other susceptible hosts is difficult. An enzyme-linked immunosorbent assay (ELISA) was developed using the excretory-secretory (ES) products of third-stage P. tenuis larvae (ES-ELISA) and the test applied to serum samples obtained from seven moose calves (5-9.5 mo old) given infective larvae (L3) in doses approximating those likely to be received in nature (3-30 L3). Anti-P. tenuis immunoglobulin G antibodies were detected in all seven inoculated moose during the course of infection until the termination of experiment 61-243 days post-inoculation (DPI). Five animals tested between 16-25 DPI had significant antibody levels, while a sixth animal did not test positive until 46 DPI. The seventh animal was not tested until 199 DPI. Antibody levels remained elevated in all five animals that harbored adult worms at the termination of the experiment. Whereas, antibody levels showed a gradual decline in the two remaining animals, presumably because of death of worms, and antibodies were undetected in one animal at the time of necropsy. The other animal displayed an anamnestic increase in antibody level following a challenge inoculation of infective larvae. Terminal and peak optical density (OD) values detected by ES-ELISA strongly correlated with inoculation dose (r = 0.98, P = 0.02 and r = 0.95, P = 0.04, respectively) among animals harboring adult worms (n = 4) but not significantly with the number of worms recovered postmortem (peak OD, r = 0.82, P = 0.18; terminal OD, r = 0.93, P = 0.07). Unlike the ES products, use of somatic antigens of the adult worm in ELISA did not provide satisfactory results. Antibodies to P. tenuis were detectable by ES-ELISA in two of 21 free-ranging moose from an enzootic area but not from any of 23 animals from a non-enzootic area. The ES-ELISA appears to be a useful test for assessing exposure of moose to P. tenuis.     

A natural case of chronic wasting disease in a free-ranging moose (Alces alces shirasi)

Chronic wasting disease (CWD) was diagnosed in a free-ranging moose (Alces alces shirasi) killed by a hunter in Jackson County, Colorado, USA, in September 2005. The diagnosis was based upon immunohistochemistry (IHC) demonstrating the presence of accumulations of CWD-associated prion protein (PrP(CWD)) in tissue sections of medulla oblongata at the level of the obex (dorsal motor nucleus of the vagus) and in retropharyngeal lymph node (RPLN); additional testing by IHC revealed deposits of PrP(CWD) in multiple sections of medulla oblongata and cervical spinal cord as well as palatine tonsil and submandibular lymph node tissues. Western blot confirmed the presence of PrP(CWD) in RPLN and tonsil tissue. The PrP(CWD) also was detected via enzyme-linked immunosorbent assay of RPLN tissue. Spongiform encephalopathy was observed in sections of the brainstem and cervical spinal cord, although no clinical signs were noted by the hunter who killed the animal. The affected moose was homozygous for methionine at codon 209 of the prion protein coding region. In October 2006, two additional free-ranging moose were diagnosed with CWD. Epidemiology and implications of CWD in moose remain to be determined.     

Dermacentor albipictus on moose (Alces alces) in Ontario.

Fifty-five moose (Alces alces) collected from 1963 to 1965 in the Chapleau Crown Game Preserve of northern Ontario were examined for ectoparasites. Dermacentor albipictus was the only parasite recovered. D. albipictus was absent from 15 moose examined during June, July and August; first observed on 1 or 2 moose examined in September; and present on all 38 moose collected from October to May. Ticks were not evenly distributed on the body. Infestations varied from 32 to 13,490 ticks/moose for 14 individuals. Levels of infestation observed did not have an obvious adverse effect on the health of the moose.     

Elaeophora schneideri in moose (Alces alces) from Colorado.

Two adult moose (Alces alces) from Colorado (USA) were naturally infected with Elaeophora schneideri. Both animals had patent infections indicating that moose may serve as definitive hosts. Gross and histological lesions were characterized by fibromuscular intimal proliferation within the carotid arteries and rete mirabile cerebri. This is the first report of Elaeophora schneideri in moose from Colorado.     

Patterns of hunting mortality in Norwegian moose (Alces alces) populations

We used a simple life table approach to examine the age-specific patterns of harvest mortality in eight Norwegian moose populations during the last 15 years and tried to determine if the observed patterns were caused by hunter selectivity. The general opinion among local managers is that hunters prefer to shoot female moose not in company with calves to keep a high number of reproductive females in the population (and because of the emotional stress involved in leaving the calf/calves without a mother), and relatively large males because of the higher return with respect to meat and trophy. In support of the former view, we found the harvest mortality of adult females to be higher among pre-prime (1–3 years old) than prime-aged age classes (4–7 years old). This is probably because prime-aged females are more fecund and, therefore, more likely to be in company with one or two calves during the hunting season. As the season progressed, however, the selection pressure on barren females decreased, probably due to more productive females becoming ‘legal’ prey as their calf/calves were harvested. In males, we did not find any evidence of strong age-specific hunter selectivity, despite strong age-dependent variation in body mass and antler size. We suggest that this was due to the current strongly female-biased sex ratio in most Norwegian moose populations, which leaves the hunters with few opportunities to be selective within a relatively short and intensive hunting season. The management implications of these findings and to what extent the results are likely to affect the future evolution of life histories in Norwegian moose populations are discussed.Electronic Supplementary Material Supplementary material is available for this article at and accessible for authorised users.     

Low-dose meningeal worm (Parelaphostrongylus tenuis) infections in moose (Alces alces)

Parelaphostrongylosis has a rapid onset and is lethal in neonatal moose (Alces alces) when large numbers of third-stage Parelaphostrongylus tenuis larvae (L3) are given experimentally. Little is known, however, about the severity and prognosis of infections acquired naturally by accidentally ingesting terrestrial gastropods which are rarely infected and have few larvae. To investigate the relationship between infecting dose, age of moose, and severity of disease, five calves were given low doses of three to 10 L3 when five (n = 2) or 9.5 mo old (n = 3). Each of two animals initially given low doses were later challenged with a dose of 15 L3. As positive controls, two calves were given doses of 15 and 30 L3, considered to be high. All five calves given low doses showed abnormal locomotory signs at 20-28 days postinoculation (DPI) that progressively became more pronounced with hind quarter weakness and front lameness. However, after 77-130 DPI, signs diminished markedly in two of these animals and disappeared in another two. Challenge infections of 15 L3 given 199 days after initial infections had no noticeable effects although an immature worm, probably resulting from the challenge, was found in the spinal cord of one animal killed 51 days later. Two positive control animals given the high doses of 15 and 30 L3 showed moderate to severe, non-resolving, locomotory signs and had to be euthanized. Results demonstrate that single, low doses of three to 10 P. tenuis L3 cause moderate disease in moose calves but over time, some worms die and animals can recover. A degree of protection may develop against future infection.     

Geographical variation of antler morphology of moose (Alces alces) in Russia

We attempt to identify geographical subdivisions within the range of moose according to antler size for a more correct trophy evaluation in the СIC system (The International Council for Game and Wildlife Conservation). Traditionally, this division coincides with subspecific division of trophy animal species. That is why we partially touch upon the problem of the geography of moose subspecies in Eurasia. Catalogs of hunters’ trophies that were available to us served as the research material (1,047 trophies in total). We were choosing the same measurements for moose antlers evaluated by different methods. They are overall spread, circumference of beam, width of palm, and number of tines. We applied multivariate statistic methods to the findings, enlarging the geographical division groups step by step. As a result, we suggest four geographical groups: European, Siberian, the north of the Far East, and the south of the Far East. In principle, this division corresponds to the subspecies: European (Alces alces alces L., 1758), east Siberian (A. a. pfizenmayeri Zukowsky, 1910), Chukotka or Kolyma (A. a. buturlini Chernyavski et. Zhelesnov, 1982), and Ussuri (А. а. cameloides Milne-Edwards, 1867). We consider it incorrect to draw the line between the European and Siberian groups along the river Yenisei. It is more correct to move it to the Urals.     

Aspects of the life cycle and pathogenesis of Elaphostrongylus alces in moose (Alces alces).

Aspects of the migratory life cycle and pathogenesis of Elaphostrongylus alces were studied in 7 randomly selected moose calves and 7 yearlings killed during August to November. One calf and 1 yearling were uninfected. The 6 infected calves had recent infections, whereas the 6 yearlings showed older infections from the summer of the previous year. The 2 calves killed in September had a total of 26 adult E. alces in the epidural space of the caudal vertebral canal and none in the skeletal muscles, whereas the remaining calves killed 1 to 2 mo later had 25 nematodes in the caudal and cranial vertebral canal and 7 in the skeletal muscles. The yearlings had a total of 101 adult E. alces in the skeletal muscles and 2 in the vertebral canal. There were no findings indicating involvement of the central nervous system in the life cycle of E. alces. Our findings suggest that E. alces migrates directly from the gut to the epidural space of the caudal vertebral canal where development to the adult stage takes place. During development, the nematode produces inflammation of the epidural tissue and spinal nerves. Development in the caudal vertebral canal is followed by some anterior dispersion of nematodes along the canal, and migration into skeletal muscles. Here the nematodes seem to live in reproductive pairs and groups. The predilection site for E. alces in moose is the muscles of the thigh.     

Tick (Dermacentor albipictus)-induced winter hair-loss in captive moose (Alces alces)

Five captive moose calves each infested with 42,000 larval Dermacentor albipictus, six calves each infested with 19,000-21,000, and five control moose were observed for changes in hair-loss, body condition and number, stages, and distribution of the tick. Winter hair-loss was observed only in moose infested with ticks and was correlated positively with the total number of adult ticks. Hair-loss associated with ticks was minimal from October to January, but rapidly increased from February to April when up to 44% of hair had been removed. The pattern of hair-loss was similar in all moose with the neck, shoulders, withers, and perianal areas losing the most hair. Moose with extensive premature hair-loss had less pericardial and abdominal visceral fat than moose with little or no hair-loss.     

Redefining physiological responses of moose (Alces alces) to warm environmental conditions

We tested the concept that moose (Alces alces) begin to show signs of thermal stress at ambient air temperatures as low as 14 °C. We determined the response of Alaskan female moose to environmental conditions from May through September by measuring core body temperature, heart rate, respiration rate, rate of heat loss from exhaled air, skin temperature, and fecal and salivary glucocorticoids. Seasonal and daily patterns in moose body temperature did not passively follow the same patterns as environmental variables. We used large changes in body temperature (≥1.25 °C in 24hr) to indicate days of physiological tolerance to thermal stressors. Thermal tolerance correlated with high ambient air temperatures from the prior day and with seasonal peaks in solar radiation (June), ambient air temperature and vapor pressure (July). At midday (12:00hr), moose exhibited daily minima of body temperature, heart rate and skin temperature (difference between the ear artery and pinna) that coincided with daily maxima in respiration rate and the rate of heat lost through respiration. Salivary cortisol measured in moose during the morning was positively related to the change in air temperature during the hour prior to sample collection, while fecal glucocorticoid levels increased with increasing solar radiation during the prior day. Our results suggest that free-ranging moose do not have a static threshold of ambient air temperature at which they become heat stressed during the warm season. In early summer, body temperature of moose is influenced by the interaction of ambient temperature during the prior day with the seasonal peak of solar radiation. In late summer, moose body temperature is influenced by the interaction between ambient temperature and vapor pressure. Thermal tolerance of moose depends on the intensity and duration of daily weather parameters and the ability of the animal to use physiological and behavioral responses to dissipate heat loads.     

Genetic diversity of moose (Alces alces L.) in Eurasia

Polymorphism of nucleotide sequence of D-loop fragment of the mitochondrial DNA was studied in 20 moose from several local populations on the territory of Eurasia. Three main haplotype variants of D-loop were detected by molecular phylogenetic method, which formed three clusters named European, Asian and American. Intraspecies variation in the length of HVSI of D-loop of the mitochondrial DNA of moose was revealed. In the Far Eastern and Yakutian moose, haplotypes with a 75-bp deletion were found, which were most similar with haplotypes (also with the deletion), earlier observed in North American moose [1]. The highest diversity of the haplotypes of mitochondrial DNA is characteristic of Yakutia and the Far East (where three haplotype variants were found), which demonstrates the probable role of the region as the center of the species or as the region of ancient population mixture. The geographic region might be considered as a probable source of ancient moose migrations from Asia to America, basing on the data of distribution of mitochondrial haplotypes of D-loop and alleles of MhcAlal-DRB1. Divergence of nucleotide sequences of haplotypes with the 75-bp deletion (forming the American cluster on the phylogenetic tree) was the lowest (0.4%), which evidences respectively recent origin of the group of haplotypes. In Europe, only haplotypes of mitochondrial DNA referred to European variant were observed. Basing on analysis of variation of nucleotide sequences of D-loop, exon 4 of kappa-Casein and exon 2 of MhcALal-DRB1, we demonstrated that Eurasian moose studied belong to the unique species, which has probably passed through a bottle neck. The time of the origin of modern diversity of D-loop haplotypes of the species was estimated as 0.075-0.15 Myr ago.     

Geographical variation in body weight and sexual size-dimorphism of Norwegian moose (Alces alces)

Geographical variation in male carcass weight, and sexual dimorphism in size was studied in 19 populations of Norwegian moose ( Alces alces (L.)).
Significant age-specific variation in male carcass weight was found for all the populations studied up to the age of 4 1/2 years, but in some populations maximum weight was not reached until at least 5 1/2 years. Increase in the mean weight of females after the age of 2 1/2 years was not significant. Only a weak relationship existed between mean yearling and adult bull weights in a population. However, within both the southern (< 62°N) and northern (> 62°N) parts of the country, yearling carcass weight was a good predictor of adult bull weight in a region.
Adult bull weight in a region was best predicted from the increment in mean carcass weight observed between 1 1/2 and 3 1/2 years of age. Within a region, variation in age-specific carcass weight between cohorts of bulls from different years was also well predicted from annual variation in growth increment.
Those patterns reveal a sexual difference in strategy of body growth. The adult weight of females is probably strongly determined by the weight gained by the time of onset of reproduction. The males have available a longer period for growth in body weight. They are therefore able to compensate for low weights early in life by increased gain of weight in later years, that provide good conditions for growth.
Geographical variation in the degree of sexual dimorphism in size correlated only poorly with adult male size. We suggest that the sexual size-dimorphism is a result of reproductive constraints of the female, i.e. in populations living in poor conditions and having small body size, the onset of reproduction prevents further gain in body weight.     

Aquatic feeding by moose Alces alces in a Canadian lake

The aquatic feeding behaviour of moose, and the abundance, species, and chemical composition of aquatic plants, were studied in a small Canadian lake which attracted many animals. Feeding was much more common in June than later in the summer, and somewhat more common during the morning and evening than in (he afternoon. Individual adult moose appeared to use the lake intensively during 1- to 4-day visits. Compared to deciduous browse, the aquatic plants had high levels of sodium and iron, less fat, and similar levels of crude protein, crude fibre, sulphate and other minerals. In the preferred feeding areas, compared to other parts of the lake, plants were more abundant, had a different species composition, and were richer in iron and calcium. Recent flooding, a flow of water through the feeding areas, and a bicarbonate-rich tributary may all have contributed to the lake's attraction for moose.     

Carfentanil and xylazine for immobilization of moose (Alces alces) on Isle Royale

Twenty-one moose were captured on Isle Royale between 28 May and 2 June 1984 at licks on the western end of the island. The animals were darted, at ranges of 10 to 35 m, with 3-cc dart syringes containing 3 or 4 mg of carfentanil and 100 or 175 mg of xylazine. Three animals were drugged with carfentanil alone. Immobilization time ranged from 2.5 to 6 min. There was no excitement phase evident in 18 of the animals and they rarely moved more than 30 m after darting. Reversal was begun at 30 to 90 min after darting using naloxone and diprenorphine given intramuscularly (i.m.) and intravenously (i.v.). Recovery time varied from 10 min to 3 hr with the longer times occurring at the higher doses of immobilizing drugs. Two animals died within 30 hr, one as the result of aspiration of rumen contents and the other was unable to get on its feet and was euthanized. Analysis of blood samples from the 18 moose immobilized with the drug combination yielded hemoglobin values of 13.1 +/- 0.3 g/dl, hematocrit: 37.6 +/- 0.7%, red blood cells: 5.46 +/- 0.1 million/microliter, leucocytes: 6.1 +/- 0.4 thousand/microliter, and serum urea nitrogen: 29.3 +/- 1.6 mg/dl. Our experience indicated that quiet, undisturbed moose can be immobilized with 3 mg carfentanil and 100 mg or less of xylazine.     

Telemetered heart rate as an index of energy expenditure in moose (Alces alces)

Metabolic rate, heart rate and respiratory rate of three adult moose were monitored simultaneously on selected days between January 1982 and October 1983. Heart rate was successfully monitored using two types of implanted radio transmitters. Metabolic rate was significantly (P less than 0.001) correlated with heart rate for individual animals (r = 0.94-0.98). The relationship was best described by an exponential equation. A mean weighted equation predicted metabolic rate within 9% of individual equations. In adult moose cows, heart rate was a more reliable predictor of energy expenditure than respiratory rate.     

Echinococcus granulosus (Cestoda: Taeniidae) infections in moose (Alces alces) from southwestern Quebec

Investigation of the distribution of larval Echinococcus granulosus in a moose population from southwestern Quebec revealed a distinct and stable pattern of infection with a prevalence of 44% (n = 580). Positive correlations between moose age and the intensity, mean cyst weight and biomass of the hydatid cysts suggested a process of continued parasite acquisition and cyst growth. The distribution of cyst sizes within individual moose provided circumstantial evidence of interaction between cysts, perhaps mediated through the host's immunological response.