Serosurvey for antibodies against Salmonella species in free-ranging moose (Alces alces) from Norway

An indirect ELISA was developed as a tool for surveillance of antibodies against Salmonella sp. in free-ranging moose (Alces alces) in Norway. Serum samples from 303 clinically healthy moose sampled between 1993-2000 were examined. Anti-Salmonella antibodies were detected in samples from 6 individuals (1.98%). This is the first evidence of Salmonella-seropositive free-ranging moose. Possible sources and transmission routes of Salmonella comprising environment, wildlife and man are discussed.     

Spontaneous aortic lesions in moose (Alces alces L)

In 17 out of 22 aortas from moose, 6 months to more than 18 years, aortic lesions were found. Five different types of lesions were observed, fatty streaks were seen in 1, fibrous plaques in 7, fatty streaks with complicated lesions (calcification and acid mucopolysaccharides) in 3, fibrous plaques with complicated lesions in 2 and fibrous plaques with complicated lesions and fat droplets in 4 of the aortas.Elastic tissue degeneration of the inner two thirds of the tunica media was principally found in the aorta of the animals beyond 4 year of age. There was no statistical evidence for a correlation between age and frequency but a trend towards age dependence was seen. The percentage of involved surface was found to increase significantly (0.05 > P > 0.02) with age. There was no significant difference between affected male and female animals in the different age groups. The frequency of involved surface in different affected regions, comprising all age groups were, in the posterior abdominal portion, 13.0 %, in the anterior abdominal portion, 3.0 %, in the posterior thoracic portion 5.2 %, in the anterior thoracic portion, 0.1 % and in the aortic arch, 0.1 %. Proliferating endothelial cells and the source of smooth muscle cells were discussed.     

Experimental Elaphostrongylus cervi infection in moose (Alces alces)

An 8-week-old male moose calf was inoculated with 360 infective third-stage larvae (L3) of E. cervi. The calf started to expel first-stage larvae (L1) of E. cervi in faeces 63 days after inoculation. The highest faecal larval count of 1,920 L1 per gram faeces was recorded 133 days post inoculation. Clinically, intermittent lameness, mild ataxia and general stiffness were observed over a 3 months’ period from day 75 after inoculation. The symptoms were moderate, faded gradually and were not seen during the last three weeks of the observation period. The calf had a good appetite and the bodyweight increased continuously throughout the experiment. On day 202 after inoculation the calf was euthanized and autopsied. Adult E. cervi were found in the epidural space of the central nervous system (CNS) and in skeletal muscles. Oedema, haemorrhages, discolouration and extensive inflammatory reactions were observed in the fat and loose connective tissue of the epidural space between the 5 th cervical vertebra and cauda equina. Nematodes or lesions indicating nematode infestation could not be demonstrated in the leptomeninges or in the neural parenchyma of the CNS. Numerous eggs and larvae of E. cervi associated with moderate pathological changes were observed in the lungs.     

Adenoviral infection in captive moose (Alces alces) in Canada.

Adenoviral infection was associated with hemorrhagic enteritis, serosal hemorrhages, and severe pulmonary edema in six captive moose (Alces alces) in Toronto, Ontario, Canada: an adult female moose and three calves in 1985 and two calves in 1998. Adenoviral disease was suspected based on histological findings of systemic vasculitis and widespread thrombosis associated with amphophilic intranuclear inclusions in endothelial cells. Diagnosis was confirmed by immunohistochemistry using antiserum to bovine adenovirus type 5, transmission electron microscopic identification of viral particles consistent in morphology with adenovirus within nuclei of pulmonary endothelial cells in an affected calf, and virus isolation. The restriction pattern of virus isolated from the lung of one of the calves indicated that the virus was identical to a recently characterized adenovirus in black-tailed deer (Odocoileus hemionus) in California. The moose adenovirus reported here may have been endemic in the captive moose herd, or infection may have resulted from either direct or indirect contact with other species of captive or wild cervids. This is the first report of adenoviral infection in moose and of the presence of adenoviral disease in a cervid in Canada.     

Attempts to transfer Elaphostrongylus alces from moose (Alces alces) to sheep and goats

Six 1 year old female and 6 four months old male goats were inoculated different numbers of E. alces third-stage larvae. Protostrongylid larvae were not detected in the faeces of these animals during the experiment. At the end of the experimental period the animals were euthanized and autopsied. Neither parasites nor pathological lesions related to larval or adult stages of E. alces could be demonstrated.     

The prevalence of Elaphostrongylus cervi infection in moose (Alces alces) in southern Norway

The prevalence of Elaphostrongylus cervi infection in moose shot during the hunting season 1983 in 47 different municipalities in Southern Norway was studied. E. cervi seemed to occur endemically in the population, as infection was found in 35 % of 1,982 moose examined. Diagnosis was made on the basis of the presence of eggs and first-stage larvae (L₁) and associated histopathological lesions in the lung, and on the presence of L₁ in the faeces. The prevalence varied considerably between different municipalities. No relationship was found between the prevalence of E. cervi and the population density of moose. The highest prevalence was found in municipalities where red deer harbouring E. cervi were also present. The prevalence among males was higher than among females, and that among yearlings higher than among calves and adults. In no case was infection found in animals 51/2 years of age or older. Carcass weight in infected adult moose was significantly lower than in non-infected adults.     

Structural variation in the nasal bone region of European moose (Alces alces L.)

The ontogeny of typical (normal) nasal bone region of the European moose (Alces alces L.) and the 3 variants of the pattern, was studied. The variants, named as "extra bone type", "punctured type" and "open type" referring the morphology of the internasal suture, were originally observed in Finnish male and female moose skulls in 1971. All of the variants were later found in hunting trophy exhibitions presenting male moose trophies from Sweden, Norway, Baltic Republics of USSR and Poland. The frequencies of the variants showed regional differences. By using histological, radiological and OTC bone labelling methods, all of the nasal bone types were observed in this study in embryonal (N = 36), newborn (N = 21), juvenile (N = 38) and adult (N = 12) moose. Two twin embryos showed different nasal bone structure. The variation is considered to be of congenital origin.     

Prevalence of antibodies against Toxoplasma gondii and Neospora caninum in moose (Alces alces) and roe deer (Capreolus capreolus) in Sweden

Toxoplasma gondii and Neospora caninum are two coccidian parasites with a worldwide distribution. T. gondii is one of the more common parasitic zoonoses in the world and in young children and immunocompromised persons, infection can lead to severe disease and death. N. caninum is an important cause of abortions in cattle. Wildlife have been identified as reservoirs and transmitters for both parasites. The purpose of this study was to investigate the seroprevalences of T. gondii, and N. caninum in moose (Alces alces), and roe deer (Capreolus capreolus) in Sweden. Blood samples were collected from 417 moose during 2000-2005 and from 199 roe deer during 1990-2007. The samples were investigated for presence of antibodies by a T. gondii direct agglutination test and a N. caninum iscom ELISA. Because the iscom ELISA has not been validated for moose or roe deer, sera that gave a positive result were further investigated by immunoblot analysis to verify presence of antibodies. Antibodies to T. gondii were detected in 85 (20%) and 68 (34%) moose and roe deer sera, respectively. In moose the seroprevalence was higher in south and central Sweden than in the north, whereas there was no difference between the regions for roe deer. Adult moose and roe deer had higher odds of being seropositive than young animals but there were no difference in seroprevalence between males and females. One roe deer was positive by immunoblotting and was regarded as N. caninum positive, whereas all moose sera were negative. The results show that T. gondii infection is widely spread in the Swedish moose and roe deer populations. Precautions should therefore be taken when handling internal organs and carcasses of harvested cervids. Proper handling and cooking of game meat also is important to prevent toxoplasmosis in humans.     

Elaphostrongylus cervi infection in moose (Alces alces). Prevalence and pathological changes in relation to age and season

The prevalence of Elaphostrongylus cervi infection in 8–10-month-old moose calves shot in March/April in Southeastern Norway was studied. The prevalence was compared with the prevalence of infection in 4–6- and 16–18-month-old animals shot in September/October. The location of adult worms, the pathological changes which they caused within the central nervous system and their pathogenicity, were also studied. Examination of 54 8–10-month-old moose calves revealed that 46 (85 %) of the calves were infected with E. cervi. Thus a considerable proportion of the calves in the areas investigated obviously became infected with E. cervi during their first summer season. The prevalence of infection seemed to decline from the age of 8–10 months in spring till the age of 16–18 months in autumn. No difference in mean carcass weight was found between infected and non-infected calves of comparable age. Within the central nervous system adult E. cervi and associated pathological changes were found exclusively in the epidural space. The high prevalence of E. cervi infection, the insignificant differences in general condition between infected and non-infected calves and the epidural location of adult worms suggest, when considered together, that E. cervi infection in general is only moderately pathogenic in moose.The lungworm Varestrongylus alces was found in 18 of 70 moose calves examined (26 %).     

Reproductive characteristics in female Swedish moose (Alces alces), with emphasis on puberty,timing of oestrus,and mating

Background

The moose (Alces alces) is an intensively managed keystone species in Fennoscandia. Several aspects of reproduction in moose have not been fully elucidated, including puberty, timing of mating and oestrus, and the length of the oestrus period. These aspects are relevant for an adaptive management of moose with respect to harvest, population size, demography and environmental conditions. Therefore, an investigation of female moose reproduction was conducted during the moose-hunting period in southern Sweden from 2008 to 2011.

Results

A total of 250 reproductive organs and information on carcass weight and age was collected from four different hunting areas (provinces of Öland, Småland, Södermanland, and Västergötland) in southern Sweden. The results showed that puberty in female moose varied with carcass weight, age, and time of season. The period for oestrous/mating lasted from about mid September to the beginning of November.

Conclusions

The oestrus period (predominantly for heifers) is longer than previously reported and was not finished when the hunting period started. Sampling the uterine cervix to detect spermatozoa was a useful method to determine if mating had occurred. To avoid hunting of moose during oestrus, we suggest that the hunting period should be postponed by at least 14 days in southern Sweden.     

A bovine viral diarrhoea/mucosal disease-like syndrome in moose (Alces alces): investigations on the central nervous system.

A disease of unknown aetiology has been observed in moose. The animals showed signs of a bovine viral diarrhoea/mucosal disease-like syndrome, and central nervous disturbances. Brains from adult female moose were investigated by means of histology, immunohistochemistry, electron microscopy, virology, and bacteriology. The results indicate that the nervous signs were not associated with a spongiform encephalopathy. The lesions suggest a viral aetiology, although all the virological investigations have so far proved negative.     

Intracytoplasmic inclusion bodies associated with vesicular, ulcerative and necrotizing lesions of the digestive mucosa of a roedeer (Capreolus capreolus L.) and a moose (Alces alces L.)

At post-mortem examination of a roedeer and a moose, ulcerative and necrotizing lesions were observed in the digestive mucosa.Both animals were serologically positive for Bovine Viral Diarrhea Virus antibodies. Histological examination revealed intra- and intercellular oedema in stratum germinativum and spinosum, formation of vesicles and ulcers, and intracytoplasmic inclusion bodies in numerous epithelial cells of mainly stratum germinativum.Electronmicroscopy confirmed the histological findings and demonstrated inclusion bodies containing a granular electron dense material encircled by a single-layer membrane. Virus particles were not found.     

Encephalitic sarcocystosis in a newborn calf

Sporozoan schizonts were seen in histologic sections of cerebrum from a Hereford calf that died immediately after birth. Schizonts appeared in endothelial cells of small vessels in the gray and white matter. Rosette and palisade configurations of merozoites in schizonts, as well as the size of schizonts (15 to 40 X 21 microns) and merozoites (8 microns), resembled Sarcocystis stages described in cattle, and differentiated the organisms from Toxoplasma that infects nerve cells and undergoes endodyogeny. Specific identification of the infecting agent was not successful because tests of sera from the calf were not possible. Developmental, morphologic, and ultrastructural differences in schizogonic stages of the heteroxenous sporozoan species infecting cattle are poorly known and are presently unreliable criteria for species identification. Encephalitis, meningitis, and necrosis occurred in cerebral, cerebellar, and brain stem gray and white matter infiltrated with plasmacytes, lymphocytes, and macrophages. Microthrombi were often seen in small blood vessels within the reaction foci. Herd-mate sera tested against S cruzi were negative. The herd from which the calf was born was exposed to a variety of free-ranging domestic, feral, and wild scavengers with free access to dead range animals. Consequently, the cattle were undoubtedly exposed to infective cysts in feed or water contaminated by feces from carnivores.