Baylisascaris procyonis (Nematoda: Ascarididae) larva migrans in free-ranging wildlife in Orange County,California

Baylisascaris procyonis is well recognized as a cause of visceral (VLM), ocular, and neural (NLM) larva migrans in birds and mammals, including man. A study of the prevalence of larva migrans in free-ranging wildlife associated with raccoon latrines as well as a retrospective study of wildlife mortalities with neurological disease was conducted in 2000 in Orange County, California. Eighty-seven birds of 18 species and 64 mammals of 8 species were found to have NLM or VLM or both. NLM clinical signs included convulsions, torticollis, opisthotonus, head-tilts, circling, ataxia, paralysis, and visual defects. NLM lesions were characterized by focally disseminated, frequently linear, "tracklike" areas of parenchymal degeneration with varying degrees of astrocytosis in the white matter of the cerebrum, cerebellum, brain stem, and spinal cord. Larvae were rarely found in these lesions but were rather isolated in the brain-spinal cord parenchyma. At least 1 larva was isolated by digestion from each case of NLM and identified as Baylisascaris sp., most likely B. procyonis. VLM lesions consisted of granulomatous reactions surrounding intact or degenerative larvae in the parenchyma of the liver, kidney, diaphragm, and, occasionally, the lymph nodes. This report broadens the range of species of wild birds and mammals that have been found to be susceptible to larva migrans caused by B. procyonis and reaffirms the importance of raccoon latrine sites as contaminative foci for wildlife.     

Latrine utilization and feces recognition in the raccoon dog,Nyctereutes procyonoides

In the raccoon dog,Nyctereutes procyonoides, utilization of latrines (defecation and urination sites), and olfactory recognition and memorization of latrine feces were studied in captivity. All individuals living within a cage utilized 1 communal latrine. The continuous and communal utilization of the latrine was based on a behavioural trait to deposit their excrement on the dung pile which was already present. They were attracted not only by their own dung pile but also by that of strange conspecifics. However, raccoon dogs could olfactorily recognize and memorize both their own feces and that of strange conspecifics individually. These results indicate that, in the raccoon dog, latrines serve as a place of information exchange about conspecific individuals, and olfactory memorization of the feces adjusts their social behaviour when they acutually encounter each other.     

Baylisascaris procyonis (Nematoda: Ascaridoidea) eggs in raccoon (Procyon lotol) latrine scats in Orange County,California

Baylisascaris procyonis is the common intestinal nematode of the raccoon and is well-recognized as a cause of visceral, ocular, and neural larva migrans in many species of wild and domestic birds and mammals, including humans. To develop data on the prevalence of B. procyonis in Orange County, California, 800 distinct raccoon latrine sites were sampled in 4 spatial zones from 15 January to 31 December 2000. Counts of fecal eggs per gram (EPG) were determined and evaluated with reference to spatial zone and season of collection. No significant differences in EPG were noted among the spatial zones. However, EPG exhibited a significant rise (37,730 +/- 1,865) in the fall and a significant decline (26,204 +/- 1,446) in the winter (ANOVA, P = 0.045). The overall egg prevalence was 100%, and the overall mean EPG was 30,265 +/- 867.     

Prevalence of Baylisascaris procyonis in habitat associated with Allegheny woodrat (Neotoma magister) populations in Indiana

Allegheny woodrat (Neotoma magister) populations have been in decline across their range since the late 1970s. Hypotheses proposed to explain these declines include habitat fragmentation and loss, decreased food availability, and increased mortality from infection with Baylisascaris procyonis. We investigated the prevalence of B. procyonis at raccoon (Procyon lotor) latrines in woodrat cliff habitats (n = 18) along the Ohio River in southern Indiana in 1995. We located 275 latrines (mean = 15.3/site; range, 6-34) and found B. procyonis in 13 (4.7%) latrines across all sites. When present at a site, B. procyonis occurred, on average, at 11.1%of latrines (range, 3-36%). Woodrat abundance, determined through a concurrent live-trapping program, was significantly higher (χ(2) = 5.12, df = 1, P = 0.024) at sites where B. procyonis was not found (9.5 ± 2.52) than at sites with B. procyonis (3.7 ± 2.2). Our analyses support the hypothesis that this parasite could contribute to declines in woodrat abundance. Because woodrats cache nonfood items, including raccoon feces, and are highly susceptible to the parasite, they are at increased risk for B. procyonis infection, which could be deleterious, especially to small populations.     

Fear of feces? Tradeoffs between disease risk and foraging drive animal activity around raccoon latrines

Fear of predation alters prey behavior, which can indirectly alter entire landscapes. A parasite‐induced ecology of fear might also exist if animals avoid parasite‐contaminated resources when infection costs outweigh foraging benefits. To investigate whether animals avoid parasite contaminated sites, and if such avoidance balances disease costs and foraging gains, we monitored animal behavior at raccoon latrines – sites that concentrate both seeds and pathogenic parasite eggs. Using wildlife cameras, we documented over 40 potentially susceptible vertebrate species in latrines and adjacent habitat. Latrine contact rates reflected background activity, diet preferences and disease risk. Disease‐tolerant raccoons and rats displayed significant site attraction, while susceptible birds and small mammals avoided these high‐risk sites. This suggests that parasites, like predators, might create a landscape of fear for vulnerable hosts. Such non‐consumptive parasite effects could alter disease transmission, population dynamics, and even ecosystem structure.     

Does a non-invasive method – latrine surveys – reveal habitat preferences of raccoon dogs and badgers?

We aimed to examine whether habitat preferences of raccoon dogs Nyctereutes procyonoides and badgers Meles meles can be revealed by using a non-invasive method, latrine surveys. We searched for latrines of these carnivores with scat detection dogs in SW Finland. We compared the results of latrine surveys with the results of a radio-tracking study conducted simultaneously in the same area. Our results showed that latrine surveys and radio-tracking gave fairly similar results: both methods revealed that raccoon dogs favoured deciduous forests, open woodland and reed beds but avoided fields, and badgers favoured deciduous and pine forests but avoided fields, gardens and reed beds. Latrines of both species were often located in the core areas but also along home range borders. Latrine survey revealed possible competition for space between the native badgers and alien raccoon dogs. Latrine survey is a non-invasive method, which gives accurate location points of animals. It could be developed further by combining it with bait-marking and by training the dogs to show us other signs of animals besides latrines.     

Frequency of deposition and location of Baylisascaris procyonis eggs in raccoon feces

Baylisascaris procyonis is a large ascarid nematode found in the small intestine of raccoons (Procyon lotor). Infection with larvae of B. procyonis can produce visceral, ocular, and neural larval migrans in humans. Infected raccoons can shed millions of eggs a day in their feces. However, it is unknown whether eggs are consistently shed or whether eggs occur at irregular intervals by the population of female nematodes within a host. We trapped, infected, and collected daily fecal samples from 11 raccoons maintained in captivity. Eggs from B. procyonis were obtained from anterior, central, and posterior sections of raccoon feces, isolated by flotation, and quantified under 100× magnification. Naturally infected raccoons were collected and used as a comparison with the experimentally infected group. All raccoons in the experimental group (n=11) became infected with B. procyonis after consuming one infected mouse. Additionally, differential egg deposition rates were observed among individual raccoons from the experimental and naturally infected groups. Mean number of eggs per gram of feces (means±SE) was 16,563±4,321, which was less than previously reported for the species. However, no differences (F(2,30)=0.84, P=0.45) were noted in mean number of eggs per gram of feces among fecal sections. Wildlife biologists, veterinarians, health officials, and researchers of B. procyonis should collect daily fecal samples for a minimum of 3 days before identifying a raccoon as negative for B. procyonis infection. However, it does not matter where within the fecal matter the sample is obtained.     

Interactions between mammals and trees: predation on mammal-dispersed seeds and the effect of ambient food

The Janzen-Connell escape hypothesis predicts that the success of tree propagules increases with distance from the parent tree. Fleshy fruits that are transported in the guts of frugivores are believed to have evolved to facilitate the wide dispersal of seeds. However, some frugivores deposit seeds in latrines, thus creating aggregations of seeds that are large enough to attract seed predators and negate the advantages of dispersal. Raccoons (Procyon lotor) often produce large seed deposits since they habitually defecate in latrines. The survival of wild black cherry (Prunus serotina) seeds in simulated raccoon latrines was monitored in areas with natural levels of food availability and in areas to which supplemental food had been supplied to the primary seed predators. Dispersal of seeds by raccoons did not necessarily provide effective protection from post-dispersal seed predation at natural food levels. Once the resident seed predators had located the latrines, the majority of the seeds were quickly removed. However, seed removal from raccoon latrines was reduced significantly and dramatically by the addition of alternative food. This implies that raccoon latrines may represent safe sites for tree recruitment during periods of high food availability such as during masting events, thus providing conditional support for the escape hypothesis.     

Himalayan musk deer (Moshcus leucogaster) behavior at latrine sites and their implications in conservation

Elusive species often use latrines which also serves as communication and information hubs. Thus, studying behavior at latrines may provide critical insights into the species’ ecology and behavior. While it is established that musk deer use latrines for defecating, very little is known about the endangered Himalayan musk deer (Moschus leucogaster) and their latrines. We examined musk deer behavior from the various video clips lasting 238 min altogether, captured at latrine sites during both breeding and non‐breeding seasons in the Annapurna Conservation Area of Nepal. A total of 428 visits by musk deer and 479 behavioral events by them were captured. We constructed an ethogram to describe musk deer behavior and compared behavior across individuals and sex using parametric and non‐parametric tests. We found that musk deer are crepuscular and nocturnal animals. Both male and female musk deer repeatedly and independently visited shared latrine sites as well as exclusively used latrine sites. The proportion of male musk deer visited latrine sites were significantly higher than that of female musk deer. Hence, male musk deer were found more active (>2 times) than females during both seasons. The most frequently observed behavioral activities at the latrine sites were defecating, sniffing and browsing, followed by scrapping and covering, and ignoring the latrine sites. The defecating and sniffing activity were performed throughout breeding and non‐breeding seasons to establish communication among peers and to claim territory. Based on the behaviors observed at the latrine sites, we can presume that Himalayan musk deer likely use latrines to convey various messages, including personality, maturity, sexual status, and territory marking among conspecifics. These findings of this study can be used for the conservation of musk deer in its natural habitat and replicated in captivity to enhance breeding performance that improves long‐term conservation prospects for this species.     

Unveiling the Limitations of Scat Surveys to Monitor Social Species: A Case Study on River Otters

Abstract: We examined the relationship between the production of sites with feces (i.e., latrines) and river otter (Lontra canadensis) abundance to determine whether scat surveys were adequate for monitoring relative population size for species leaving activity signs in a clumped distribution on the landscape. We conducted winter riparian transects to simultaneously monitor otter abundance via snow tracks and latrine sites along the rivers of Kouchibouguac National Park and surrounding area in New Brunswick, Canada. Our data showed that latrine abundance poorly reflected otter abundance for given stretches of rivers because the relationship was nonlinear and reached a plateau. The number of latrine sites was not related to the time period since last snowfall, which indicated that otters repetitively defecated at the same sites. Individual otters and groups did not produce activity signs over larger distances as a function of time, which indicated that they tend to stay in their home ranges in winter. We discuss why scat survey protocols based on determining presence—absence of a species at predetermined search sites may poorly reflect population size, as well as population fluctuations in time. Caution is advised when interpreting data from such surveys for species for which feces or other activity signs surveyed play a role in intraspecific communication and tend to be in a clumped distribution on the landscape.     

Raccoon dog scent marking by scats and its significance in social behaviour

Utilization pattern of latrines by raccoon dogs,Nyctereutes procyonoides viverrinus, was studied on a small island in western Kyushu, Japan. Seventy-eight latrines were spread over the study areas, these were mainly formed on the flat surface in woody areas. Although the site and number of latrines were fairly stable throughout the year, distribution of the utilized latrines and number of scats per latrine were changed seasonally. Latrines were grouped into several clusters and communal utilization of latrines by several animals was observed within the cluster. Seasonal changes of utilization pattern observed in communal utilization rate and cluster formation was assumed to be caused by the changing of the social unit of raccoon dogs. Familiarization within the home range and information site to conspecifics may be concluded as the function of latrines.     

Helminths of the raccoon (Procyon lotor) in western Kentucky

Seventy raccoons (Procyon lotor) from western Kentucky were examined for helminths from December 1985 through May 1986. Twenty-three species of helminths were collected including 10 species of Trematoda (Brachylaima virginiana, Euryhelmis squamula, Eurytrema procyonis, Fibricola cratera, Gyrosoma singulare, Maritreminoides nettae, Mesostephanus appendiculatoides, Metagonimoides oregonensis, Paragonimus kellicotti, Pharyngostomoides procyonis), 2 species of Cestoda (Atriotaenia procyonis, Mesocestoides variabilis), 10 species of Nematoda (Arthrocephalus lotoris, Baylisascaris procyonis, Capillaria putorii, C. plica, Crenosoma goblei, Dracunculus insignis, Gnathostoma procyonis, Molineus barbatus, Physaloptera rara, Trichinella spiralis), and 1 species of Acanthocephala (Macracanthorhynchus ingens). A mean of 6.4 (3-11) helminth species per host was recorded. Fibricola cratera, Atriotaenia procyonis, Mesocestoides variabilis, Arthrocephalus lotoris, Capillaria plica, Dracunculus insignis, Molineus barbatus, and Physaloptera rara were ubiquitous parasites of the raccoon, whereas specific nidi were observed for Eurytrema procyonis, Gyrosoma singulare, Paragonimus kellicotti, Baylisascaris procyonis, Trichinella spiralis, and Macracanthorhyncus ingens. With an overall prevalence of 10% or higher, 15 of the 23 helminth species were considered common parasites of the raccoon in western Kentucky. When the 10% prevalence rate was applied within geographical quadrants to correct for the presence of nidi it was found that 18 of the 23 helminth species were common and 5 were regarded as rare parasites of the raccoon. Two species of nematodes, T. spiralis and B. procyonis, displayed a markedly higher prevalence in male raccoons.     

Fruits foraging patterns and seed dispersal effect of frugivorous birds on Hippophae rhamnoides sinensis

Behaviors of 18 species of birds eating fruits of Hippophae rhamnoides spp.sinensis were observed from September 2003 to March 2004.Their foraging patterns were found to be very different and Can be divided into five classes:(1)direct swallowing the fruits on crown of the shrubs and sometimes regurgitating seeds soon after;(2)carrying the fruits to their perching sites and swallowing;(3)pecking the fruits from the shrubs to the ground,eating pulp and seeds but leaving pericarp;(4)pecking through the pericarp,eating pulp and leaving pericarp and seeds;(5)pecking through the pericarp on the top of fruits,and only eating seeds.These foraging patterns have different effects on seed dispersal of H.rhamnoides spp.sinensis.The germination experiment of three groups of seeds(seeds from feces,dry fruits and extracted seeds from dry fruits)was carried out.Although ingestion processes of birds had some adverse effects on the seed germination of H.rhamnoides spp.sinensis,the seeds from feces still have a relatively higher germination ratio.H.rhamnoides spp.sinensis provides food to a variety of frugivorous birds.and the birds disperse its seeds.Thus,a mutually beneficial relationship between the bird and the seed is formed.     

Food of the zebra finch (Poephila guttata), and an examination of granivory in birds of the Australian arid zone

Birds are important granivores in the Australian arid zone, and this paper reviews their role by assembling available data on diet and habitat selection of the granivorous species occurring in the region. Paucity of dietary information is alleviated by a study of the food of the zebra finch (Poephila guttata) at two sites in the eastern arid zone. Zebra finches subsisted entirely on grass seeds of a relatively narrow specific range; 17 classes of seeds (at least 19 species) were eaten, but one class dominated the diet at each study site and only five classes (probably six species) were significant overall. Comparative information concerning granivorous species- suggested that the seeds of grasses and shrubs are of most importance in diets, that larger species tended to eat larger seeds from a wider variety of plants because of the addition of shrub species to the diet, and that Acacia shrublands contained most species. Characteristics of the arid zone that are of particular importance to granivorous birds appear to be the abundance of grasses and the patchy and erratic nature of the rainfall.     

Land-use effects on prevalence of raccoon roundworm (Baylisascaris procyonis)

The raccoon (Procyon lotor) is the definitive host of Baylisascaris procyonis, a large intestinal roundworm that is zoonotic and can result in fatal or severe central nervous system disease in young children. Prevalence of infection among raccoon populations often is high, and in the midwestern United States, B. procyonis has been reported in 68-82% of raccoons. Raccoon populations have increased in response to changes in human land use, and often reach higher densities in urban and suburban landscapes than rural landscapes. However, shifts in foraging behavior among urban raccoons could impact the transmission of B. procyonis if small vertebrate intermediate hosts are not a significant part of the raccoon diet. The objective of this study was to compare prevalence of B. procyonis infection between urban and rural raccoon populations on a regional scale. Necropsy was done on 204 raccoons collected from September through February during 2000-2005 from seven states across the Midwest (regional sample). Baylisascaris procyonis was found in 54% of examined raccoons. Prevalence differed between land-use types (chi2=11.56, df=1, P=0.0007), and was higher among animals collected from rural locations (65%) than those collected in urban locations (41%). Intensity of infection also differed (F=5.52, df=1, P=0.02), with rural raccoons having greater worm burdens (x=29.63+/-36.42) than urban raccoons (x=13.85+/-18.47). Despite high densities of raccoons in urban landscapes, fewer urban raccoons were infected with B. procyonis, suggesting decreased dependence on intermediate hosts as a food source. This possible explanation was supported by a similar trend in prevalence among subsamples of raccoons collected from three Chicago-area populations (local samples) with differing levels of urbanization, population densities, and foraging behavior that had been intensively monitored during 1995-2002. Decreased transmission of B. procyonis in urban landscapes may be due to decreased predation of intermediate hosts, and contact of juvenile raccoons with B. procyonis eggs may be an important factor in maintaining infections within such populations.     

Removal of post-dispersed seeds in Acacia cyclops thickets under biological control in South Africa

Biological control programmes have been mounted against all invasive Australian acacias with two agent species, Melanterius servulus (seed feeding weevil), and Dasineura dielsi (flower galling midge), being released on Acacia cyclops (rooikrans) in 1991 and 2002 respectively. Both of these agents are prolific and are causing high levels of damage, resulting in reduced seeding capacity of A. cyclops which in turn is expected to limit the invasiveness of the species. As part of an ongoing study to determine the long-term effectiveness of the biological control programme, we measured seed removal rates of A. cyclops by invertebrates and vertebrates, and the composition of granivorous species, to determine how these compare with earlier studies when there was no biological control. Results show that in A. cyclops thickets under biological control, 13% of seeds were removed by invertebrates 59% by rodents and 15% by ground-foraging birds and large mammals within 24 h. The removal rates of seeds with arils intact were double than those of seeds without arils. Camera traps captured 10 vertebrate species comprising six birds and four mammals including Mellivora capensis Storr (Cape ratel) and Raphicerus melanotis Thunberg (Cape grysbok) consuming seeds from stashes. The most frequent visitors were Rhabdomys pumilio (striped mouse), Streptopelia capicola (Cape turtledove) and Cossypha caffra (Cape robin-chat) (33%, 27% and 20% of visits respectively). We conclude that levels of granivory and the composition have not changed substantially with biological agents in the system.     

Competition between birds and mammals: A comparison of giving-up densities between crested larks and gerbils

We combined the concept of mechanisms of co-existence with the approach of giving-up densities to study inter-taxon competition between seed-eating birds and mammals. We measured feeding behaviour in food patches to define and study the guild of seed-eating vertebrates occupying sandy habitats at Bir Asluj, Negev Desert, Israel. Despite a large number of putatively granivorous rodents and birds at the site, two gerbil species (Allenbys gerbil, Gerbillus allenbyi, and the greater Egyptian gerbil, G. pyramidum) dominated nocturnal foraging, and a single bird species (crested lark, Galerida cristata) contributed all of the daytime foraging. We used giving-up densities to quantify foraging behaviour and foraging efficiencies. A low giving-up density demonstrates the ability of a forager to profitably harvest food at low abundances and to profitably utilize the foraging opportunities left behind by the less efficient forager. Gerbils had lower giving-up densities in the bush than open microhabitat, and lower giving-up densities in the semi-stabilized than stabilized sand habitats. Crested larks showed the opposite: lower giving-up densities in the open than bush, and on the stabilized than semi-stabilized sand habitats. Despite these patterns, gerbils had substantially lower giving-up densities than crested larks in both microhabitats, all sand habitats, and during each month. Several mechanisms may permit the crested lark to co-exist with the gerbils. Larks may be cream skimmers on the high spatial and temporal variability in seed abundances. Larks may rely on insects, fruit or smaller seeds. Or, larks may rely on adjacent rocky habitats.     

Helminth parasites of an introduced invasive carnivore species, the raccoon ( Procyon lotor L.), from the Warta Mouth National Park (Poland)

We evaluated helminth parasites of the introduced North American raccoon ( Procyon lotor L.) in Poland. From June 2006 to May 2007, 91 raccoon fecal samples were collected in the Warta Mouth National Park situated in western Poland near the Polish-German border. Coprological analyses involved flotation and sedimentation. In total, 7 helminth taxa were identified in the feces: Ancylostoma spp., Baylisascaris procyonis, Capillariidae, Placoconus lotoris, Spirocerca lupi, Strongyloides procyonis, and Echinostoma sp. The parasite assemblage in the raccoon exhibited a low diversity. The results were compared with data from other European and North American studies and suggest a lower prevalence of parasites in newly invaded areas, compared with earlier invaded areas or the native range.     

Different contributions of birds and mammals to seed dispersal of a fleshy-fruited tree

Birds and mammals are important seed dispersers of fleshy-fruited plants. Although their behaviors are different, they frequently consume the same species. Thus to understand the dispersal of fleshy-fruited plants, the contribution of birds and mammals to seed dispersal has to be evaluated. Besides, within birds or mammals, some species may functionally different from others. In this study, we examined seed dispersal of the fleshy-fruited tree Swida controversa focusing on the difference between two frugivore groups (birds and mammals), and differences between species within groups. Collected seeds and S. controversa trees were identified using simple sequence repeat (SSR) genotyping, thus enabling to determine the distance between mother tree and dispersed seeds. The avian species were identified by DNA barcoding of feces, whereas the mammalian species were identified by the shape and smell of feces. Most seeds that fell near or under the maternal trees were dispersed by birds, resulting in short seed dispersal distances (average, 13 m). DNA barcoding detected five taxa of avian dispersers. No differences were detected in seed dispersal distance by different avian taxa (i.e., the distance between dispersed seeds and their maternal trees within the research plot); however the rate of seed immigration from outside the research plot by some avian taxa varied significantly. The seed dispersal distance by mammals was significantly further (127 m; min > 50 m) than that by birds. Additionally, immigrated seeds accounted for approximately two-thirds of mammal-dispersed seeds, indicating that these seeds were from outside the research plot, and that mammals significantly contributed to the long-distance seed dispersal of S. controversa. No differences in seed dispersal distance were detected between different mammalian taxa. Overall, this study revealed that birds and mammals show clearly different seed dispersal patterns, and thus, they play different roles in the regeneration of S. controversa.     

Survey of raccoons on Key Largo, Florida, USA, for Baylisascaris procyonis

Numbers of the endangered Key Largo woodrat (KLWR; Neotoma floridana smalli) have been declining for at least 25 yr. The raccoon (Procyon lotor) roundworm, Baylisascaris procyonis, has been found to have an adverse effect on the survival of Alleghany woodrats (N. magister). High densities of raccoons can exacerbate this problem by increasing the amount of feces containing viable eggs of B. procyonis available to woodrats. In 2002, 64 fecal samples were collected and examined for eggs of B. procyonis from >32 raccoons within the KLWR's known range on Key Largo, Florida, USA. All samples were negative for eggs of B. procyonis. Raccoon density in this area was approximately 0.62 raccoons/ha. Despite this high density of raccoons, B. procyonis does not appear to be a threat to the KLWR population.