Cerebrospinal nematodiasis in a moose in Norway

A case of cerebrospinal nematodiasis in a young adult moose (Alces alces) from Telemark county, southeastern Norway, is described. The moose was found by bird hunters during January, displaying signs of severe posterior paresis. It was killed and submitted for autopsy. The carcass was emaciated, and there were skin excoriations and subcutaneous edema over both metacarpi. Histopathologic examination revealed traumatic malacia throughout the spinal cord and meningeal accumulations of mononuclear inflammatory cells and eosinophils in brain and spinal cord. Two adult female nematodes were found in sections, respectively, of the subarachnoid and subdural spaces of the thoracic spinal cord. The nematode cross sections were similar with those of the two neurotropic Elaphostrongylus species, E. rangiferi and E. cervi. The moose originated from an area overlapping the grazing area of a large population of wild reindeer (Rangifer tarandus tarandus) living on the mountain plateau of Hardangervidda, suggesting the moose was infected with E. rangiferi from reindeer.     

High Prevalence of Hepatitis E Virus in Swedish Moose – A Phylogenetic Characterization and Comparison of the Virus from Different Regions

Background

Hepatitis E virus (HEV) infects a range of species, including humans, pigs, wild boars and deer. Zoonotic transmission may contribute to the high HEV seroprevalence in the human population of many countries. A novel divergent HEV from moose (Alces alces) in Sweden was recently identified by partial genome sequencing. Since only one strain was found, its classification within the HEV family, prevalence in moose and zoonotic potential was unclear. We therefore investigated samples from 231 moose in seven Swedish counties for HEV, and sequenced a near complete moose HEV genome. Phylogenetic analysis to classify this virus within the family Hepeviridae and to explore potential host specific determinants was performed.

Methods and Findings

The HEV prevalence of moose was determined by PCR (marker for active infection) and serological assays (marker of past infection) of sera and 51 fecal samples from 231 Swedish moose. Markers of active and past infection were found in 67 (29%) animals, while 34 (15%) were positive for HEV RNA, 43 (19%) were seropositive for anti-HEV antibodies, and 10 (4%) had both markers. The number of young individuals positive for HEV RNA was larger than for older individuals, and the number of anti-HEV antibody positive individuals increased with age. The high throughput sequenced moose HEV genome was 35-60% identical to existing HEVs. Partial ORF1 sequences from 13 moose strains showed high similarity among them, forming a distinct monophyletic clade with a common ancestor to HEV genotype 1-6 group, which includes members known for zoonotic transmission.

Conclusions

This study demonstrates a high frequency of HEV in moose in Sweden, with markers of current and past infection demonstrated in 30% of the animals. Moose is thus an important animal reservoir of HEV. The phylogenetic relationship demonstrated that the moose HEV belonged to the genotype 1-6 group, which includes strains that also infect humans, and therefore may signify a potential for zoonotic transmission of this HEV.     

Susceptibility of Amblyomma americanum to natural and experimental infections with Theileria cervi

One hundred fifty Amblyomma americanum were examined between March and September 1986 from Cookson Hills Wildlife Refuge in eastern Oklahoma (USA). Of these ticks, 11% (17 of 150) were infected with Theileria cervi. Field-collected nymphal ticks had an 8% (3 of 37) prevalence of infection averaging 1.0 infected acini/nymph. Female ticks had a 16% prevalence of infection averaging 1.6 infected acini/female; T. cervi was not observed in salivary glands of field-collected male ticks. When laboratory reared A. americanum nymphs were allowed to feed on experimental white-tailed deer (Odocoileus virginianus) with varying T. cervi parasitemias (less than 1, 2, 6 and greater than 20%), only ticks which fed on deer with parasitemias greater than 1% became infected. Although prevalence and intensity of infection varied in the infected ticks, there was no significant difference in prevalence of infection between males and females. However, females did acquire significantly greater intensities than males. The data from these studies confirm that T. cervi overwinters in A. americanum and suggests that the prevalence, intensity and abundance of infection of T. cervi in ticks is influenced by the parasitemia of the deer host. Furthermore, fawns may play a more important role in the epidemiology of T. cervi transmission than do adult deer because of the coordination between tick activity patterns and deer fawning.     

A comparative study of hepatic trace element levels in wild moose, roe deer, and reindeer from Norway

Liver samples from 422 wild moose (Alces alces), 280 roe deer (Capreolus capreolus), and 73 reindeer (Rangifer tarandus) collected by hunters in various localities in Norway, 2002-2003, were analyzed for the essential trace elements cobalt, copper (Cu), manganese (Mn), molybdenum, selenium (Se), and zinc. Significant differences in hepatic concentrations among species were found for all elements except for Mn, and considerable individual and geographic variations were seen. Roe deer had statistically significant lower Se levels (median: 0.51 μg Se/g dry weight) than did moose (0.77 μg Se/g) and reindeer (0.85 μg Se/g). Moose from two coastal municipalities with high precipitation had considerably higher Se concentrations than those from the other localities studied. Seventy-nine roe deer (28%) and 36 moose (9%) had Se concentrations below that regarded as deficient in domestic ruminants. The Se status in roe deer was lower than previously reported in Europe. Moose had a significantly higher Cu (222 μg Cu/g dw) than did roe deer (112 μg Cu/g) and reindeer (105 μg Cu/g). The Cu status of moose and roe deer in Norway are among the highest reported in Europe. However, a suboptimal Se and Cu status was found in moose from Tvedestrand, a population which has suffered from a reduced condition and productivity. The variability in trace element status among hunted cervids, with no apparent signs of deficiency or toxicity, probably reflects adaptations in these wild ruminant species to cope with this. However, subtle clinical signs and lesions are difficult to detect and further research is needed.     

Infection of red foxes with Echinococcus multilocularis in western Switzerland

In the Jura mountains, Plateau and Alps of western Switzerland important variations in the prevalence of Echinococcus multilocularis infection in red foxes were observed between geographical areas from 1990 to 1995. The Jura mountains and the Plateau had higher mean prevalence levels than the Alps with 30.6, 32.4 and 18.8%, respectively. The highest rate was recorded in the Plateau in the canton of Fribourg with a prevalence of 52.3%. The prevalence of E. multilocularis infection in foxes in the alpine canton of Valais was the lowest (7.1%). Juvenile foxes were found to be more susceptible to E. multilocularis than adults. Adult foxes were less heavily infected in summer and autumn, while the prevalence in juveniles (less than 1 year old) increased between the spring and winter, when they are more than 6 months old. The retrospective data relate to the beginning of the 1990s, since when a drastic prevalence increase of E. multilocularis infection in foxes has occurred in several regions of Europe. Nevertheless, the study is a major contribution to the epidemiological situation of E. multilocularis in central Europe, in that it contains valuable information on spatial distribution and seasonal differences in different age groups of foxes.     

Presumptive gangrenous ergotism in free-living moose and a roe deer

Presumptive gangrenous ergotism in 10 moose (Alces alces) and one roe deer (Capreolus capreolus) is reported. Three of the moose came from a municipality in southeastern Norway where the disease occurred as a cluster in 1996. The other moose represented solitary or sporadic cases diagnosed in four municipalities in northwestern Norway between 1996 and 2004. Affected moose (seven calves, three yearlings) were found between October and June, showing distal limb lesions on one to three limbs. The lesions in the moose found during October and November presented as dry gangrene, whereas moose found between December and June presented with loss of the distal part of the limbs or open lesions close to sloughing. Four of the moose also had bilateral ear lesions affecting the outer third of the pinnae. A retrospective diagnosis of ergotism (June 1981) was made in a 1-yr-old roe deer from northwestern Norway showing loss of the distal part of all four limbs.     

The distribution of <Emphasis Type="Italic">Echinococcus granulosus</Emphasis> in moose: evidence for parasite-induced vulnerability to predation by wolves?

The role of parasites in influencing the trophic dynamics of hosts is becoming increasingly recognized in the ecological literature. Echinococcus granulosus is a tapeworm that relies on the predator-prey relationship between the definitive host (wolf, Canis lupus) and the intermediate host, (moose, Alces alces) to complete its life cycle. Heavy infection by E. granulosus may predispose moose to increased risk of predation by wolves. Theory predicts that parasite-induced vulnerability to predation will reduce the degree of aggregation of parasites in a host population. We tested for different levels of aggregation of E. granulosus in moose in areas of low, moderate, and high levels of wolf predation using Greens coefficient of dispersion. Parasite aggregation was lower in an area with high predation rate, thus we hypothesize that heavy infection by E. granulosus predisposes moose to predation by wolves. This increase in predation rate due to parasite infection may influence the role of wolves in regulating moose populations. We discuss alternative explanations for the negative correlation between predation rate and parasite aggregation.An erratum to this article can be found at     

Antibodies to granulocytic Ehrlichia in moose, red deer, and roe deer in Norway

Serum samples from 104 moose (Alces alces), 124 red deer (Cervus elaphus) and 114 roe deer (Capreolus capreolus), collected from different counties in southern Norway from 1994 to 2000, were analysed by an indirect immunofluorescent antibody staining method for antibodies to Ehrlichia equi. The overall seroprevalences for granulocytic Ehrlichia spp. in moose, red deer, and roe deer from Ixodes ricinus infested counties were 43%, 55%, and 96%, respectively. Antibody prevalence was significantly higher in roe deer than in moose and red deer (P < 0.001). Mean antibody titers (log10 +/- SD) to E. equi in sera from moose, red deer, and roe deer were 1:1,497 (3.17 +/- 0.646), 1:234 (2.37 +/- 0.424) and 1:676 (2.83 +/- 0.404), respectively. The present work indicates that all these wild ruminant species are exposed to granulocytic Ehrlichia in Norway.     

The non-impact of hunting on moose <Emphasis Type="Italic">Alces alces</Emphasis> movement,diurnal activity,and activity range

Previous studies on moose Alces alces have suggested that interactions with humans may trigger anti-predator behaviors and generate a demographical cost. Therefore, we hypothesized that disturbances from small and big game hunting may have negative effects on moose movements, diurnal activity, and activity range. Using location data from 64 moose equipped with GPS collars from three populations (Low Alpine, Inland, Coastal) with different temporal human presence and spatial accessibility, we evaluated the impact of hunting on moose activity rhythms. On average, female moose in the low human population density (Low Alpine) area (<0.5/km²) had significantly lower movement rates during moose hunting season, but variation in movement rates among individuals were higher compared with female moose in regions with denser human populations (6–24/km²). We found no evidence that reproductive status influenced female moose sensitivity to disturbance. As expected, females used smaller activity ranges and were less active nocturnally than males. The high within-group variation suggests that current hunting disturbance levels do not alter moose population behavior in general. Our data indicate that alterations in movement were related to rutting activity, not human disturbance induced by hunting. In line with behavioral theory, our study suggests that some individuals were more sensitive to hunting disturbance than the general population. Our work suggests that individual moose may perceive human predation risk to be similar to other predation risks.     

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.     

Associations between host migration and the prevalence of a protozoan parasite in natural populations of adult monarch butterflies

1. Monarch butterflies Danaus plexippus (L.) (Lepidoptera: Nymphalidae) are susceptible to infection by the obligate protozoan parasite Ophryocystis elektroscirrha (McLaughlin and Myers) (Apicomplexa: Neogregarinida). Because monarchs form resident and migratory populations in different parts of the world, this host–parasite system provides the opportunity to examine how variation in parasite prevalence relates to host movement patterns. 2. Parasite prevalence was evaluated using 14 790 adult monarchs captured between 1968 and 1997. Comparison of three populations in North America indicated that parasite prevalence is associated negatively with host dispersal distances. A continuously breeding, nonmigratory population in southern Florida showed high prevalence (over 70% heavily infected). The western population migrates moderate distances to overwintering sites on the Pacific Coast and has intermediate prevalence (30% heavily infected). The eastern migratory population, which travels the longest distance to Mexican overwintering sites, has exhibited less than 8% infection throughout the past 30 years. 3. Variation in parasite loads within North American migratory populations was investigated to determine whether the prevalence of heavy infection and average parasite loads declined during migration or overwintering. Average parasite loads of summer‐breeding adults in western North America decreased with increasing distance from overwintering sites. This suggests that heavily infected monarchs are less likely to remigrate long distances in spring. No differences in the frequency of heavily infected adults were found among eastern or western North American monarchs throughout the overwintering period, however, suggesting that this parasite does not affect overwintering mortality. 4. Changes in the prevalence of monarchs with low parasite loads demonstrate that spore transfer occurs during migration and overwintering, possibly when adult butterflies contact each other as a result of their clustering behaviour. 5. This study of geographical and temporal variation in O. elektroscirrha among populations of D. plexippus demonstrates the potential role of seasonal migration in mediating interactions between hosts and parasites, and suggests several mechanisms through which migratory behaviour may influence parasite prevalence.     

Prevalence of patent Baylisascaris procyonis infection in raccoons (Procyon lotor) in Ithaca, New York

The prevalence of patent Baylisascaris procyonis infection in raccoons was determined by examining fecal samples collected between July 1986 and May 1987 in Ithaca, New York. September, October, and November had the highest prevalence of infection (35-48%). Significant differences (P less than 0.001) were found when months were grouped by season to test the hypothesis that a fecal sample's probability of being positive does not vary from month to month. Fall was the season contributing most to the overall chi-square statistic. Host sex/age class and prevalence of patent infection were investigated. The raccoons were aged as either juveniles or adults. A significantly higher prevalence of patent infection (P less than 0.001) was found in juveniles when compared to adults. No statistically significant difference was found in other comparisons of host sex and age. Contingency analysis tested the independence of sex/age class/season and presence of eggs. The results of the test were significant (P less than 0.001).     

Trends in undernutrition mortality among children under five years of age and adults over 60

Introduction: Children under five years of age living in poor areas and with low availability of healthy food have a higher risk of undernutrition-related mortality. However, this relationship has not been well established among older adults.Objective: To analyse socioeconomic inequality trends related to undernutrition mortality in children under five years of age and adults over 60 in Colombian municipalities during 2003-2009 and 2010-2016.Materials and methods: We conducted an ecological study of trends between 2003 and 2016. The study population consisted of children under five years of age and adults over 60 residing in the Colombian municipalities during the study period. We estimated smoothed and standardized mortality rates by fitting a hierarchical Bayesian model and explored their relationship with five socioeconomic area-level variables.Results: In most of the municipalities, undernutrition-related mortality was three times higher in older adults compared to children. Moreover, the difference in the risk of undernutrition-related mortality between municipalities showed a marked reduction. Finally, the poor and less developed municipalities had higher rates of undernutrition-related mortality in children; conversely, wealthier territories had higher rates in older adults.Conclusions: Although in most of the municipalities the mortality rates due to undernutrition in children under five and older adults have decreased, their socioeconomic conditions influence in different ways the risk of mortality for these two populations so there is the need to develop age-specific strategies to close social gaps considering the structural conditions of the areas.     

Parelaphostrongylus tenuis in New Brunswick: the parasite in white-tailed deer (Odocoileus virginianus) and moose (Alces alces)

Research was initiated in 1983 to investigate the ecology of Parelaphostrongylus tenuis in New Brunswick. The objectives were to determine the prevalence and intensity of infection in white-tailed deer, and to determine whether or not moose feces contained first stage larvae, signifying the completion of the life cycle of P. tenuis in this host. Forty-nine percent of deer pellet samples were positive and 60% of deer heads contained adults of P. tenuis. None of the moose pellet samples contained first stage larvae.     

Hypodermosis of red deer in Spain

From February 1998 to January 1999, 106 red deer in the Autonomic Organism National Park "Quintos de Mora" (Toledo, central Spain) were evaluated to determine the prevalence and dynamics of infection with Hypoderma sp. by detection of subcutaneous larvae. Between six and 13 deer shot in selective hunting were examined monthly. Hypoderma sp. larvae were detected throughout the period except in June, July and August of 1998. Excluding the period during which no subcutaneous larvae were detected, the number of animals sampled was 80 (52 males and 28 females), belonging to three age classes: 12 calves (<1-yr-old), 19 yearlings (1-yr-old), and 49 adults (2- to 10-yr-old). All the third instar (L3) collected were identified as H. actaeon. Total prevalence during the period of larval detection was 61%. Prevalence in yearling and adult deer shot during the official hunting season was 89%. Monthly prevalence increased from September to January and decreased from February to May. In September and October, a small percentage of larvae were classified as first instar (L1). The rest of larvae collected between September and December were second instar (L2). Third instar (L3) predominated in January and February and was the only stage collected from March to May. Intensity ranged from 1 to 145 larvae. Intensities were >100 larvae in 6% of animals. Possible relationships of intensity or prevalence of infection with sex or age of the animals were evaluated. Significant differences in prevalence were observed among different host age classes. Prevalence was higher in yearlings (84%) than in adults (63%) and lowest in calves (17%).     

Epidemiology of cerebrospinal Elaphostrongylus cervi infection in red deer in central Spain

Elaphostrongylus cervi produces a subclinical cerebrospinal disease in many wild and domestic ruminants from Europe, North America and New Zealand and has recently been described in Spain. To determine some aspects of its epidemiology, 121 red deer (Cervus elaphus) from central Spain were sampled during 2000. The prevalence (7%) and mean worm burden (3.8 worms per brain) were similar to the values previously recorded in other European areas. The infection was only detected in young deer during the winter. The estimation of larval production in the faeces was not a reliable method of diagnosing E. cervi infection.     

Introduced pathogens follow the invasion front of a spreading alien host

1.?When an invasive species first colonizes an area, there is an interval before any host-specific natural enemies arrive at the new location. Population densities of newly invading species are low, and the spatial and temporal interactions between spreading invasive species and specific natural enemies that follow are poorly understood. 2.?We measured infection rates of two introduced host-specific pathogens, the entomophthoralean fungus Entomophaga maimaiga and the baculovirus Lymantria dispar nucleopolyhedrovirus (LdNPV), occurring in spreading populations of an invasive forest defoliator, L. dispar (gypsy moth), in central Wisconsin. 3.?Over 3 years, we found that host density was closely associated with the presence and prevalence of both pathogens. The fungal and viral pathogens differed in the sensitivity of their response as E. maimaiga was present in lower-density host population than LdNPV. 4.?We examined the relationship between weather conditions and infection prevalence and found that activity of both the fungus and virus was strongly seasonally influenced by temperature and rainfall or temperature alone, respectively. 5.?Purposeful releases of pathogens (median distances of study sites from release sites were 65·2 km for E. maimaiga and 25·6 km for LdNPV) were not associated with pathogen prevalence. 6.?A generalist fly parasitoid, Compsilura concinnata, also killed L. dispar larvae collected from the study sites, and parasitism was greater when infection by pathogens was lower. 7.?Our results demonstrated that although infection levels were low in newly established host populations, host-specific pathogens had already moved into host populations close behind advancing populations of an invasive host; thus, spreading hosts were released from these enemies for only a relatively short time.     

野外围栏条件下根田鼠肠道寄生物的感染率

寄生物是调节小哺乳动物种群波动的因子之一。许多生物和非生物因子可影响寄生物的感染。本研究以根田鼠为对象,在野外围栏条件下测定了根田鼠肠道寄生物种类及其感染率,并分析了根田鼠建群者数量、性别、年龄及时间对寄生物感染率的影响。结果表明,根田鼠肠道寄生物有球虫、线虫和绦虫,球虫是主要寄生物, Eimeria wenrichi 为球虫中的优势种;其感染率随根田鼠建群者数量增加而增加,且随时间而显著变化。在根田鼠幼体中,高密度处理组E. wenrichi 的感染率显著高于低密度处理组,而根田鼠幼体的E. ochrogasteri 感染率显著高于成体。本研究未发现根田鼠性别间的球虫感染率差异。上述结果说明,在根田鼠种群中,球虫感染率有时间变化,且受宿主密度的制约,高密度种群引起的生前应激与当前密度制约性感染可能对球虫感染率具有耦合效应。     

Population structure and genetic diversity of moose in Alaska

Moose (Alces alces) are highly mobile mammals that occur across arboreal regions of North America, Europe, and Asia. Alaskan moose (Alces alces gigas) range across much of Alaska and are primary herbivore consumers, exerting a prominent influence on ecosystem structure and functioning. Increased knowledge gained from population genetics provides insights into their population dynamics, history, and dispersal of these unique large herbivores and can aid in conservation efforts. We examined the genetic diversity and population structure of moose (n = 141) with 8 polymorphic microsatellites from 6 regions spanning much of Alaska. Expected heterozygosity was moderate (H(E) = 0.483-0.612), and private alleles ranged from 0 to 6. Both F(ST) and R(ST) indicated significant population structure (P < 0.001) with F(ST) < 0.109 and R(ST) < 0.125. Results of analyses from STRUCTURE indicated 2 prominent population groups, a mix of moose from the Yakutat and Tetlin regions versus all other moose, with slight substructure observed among the second population. Estimates of dispersal differed between analytical approaches, indicating a high level of historical or current gene flow. Mantel tests indicated that isolation-by-distance partially explained observed structure among moose populations (R(2) = 0.45, P < 0.01). Finally, there was no evidence of bottlenecks either at the population level or overall. We conclude that weak population structure occurs among moose in Alaska with population expansion from interior Alaska westward toward the coast.