Parasitic helminths of black bear cubs (Ursus americanus) from Florida

Twenty-two Florida black bear (Ursus americanus floridanus) cubs (< or = 12 mo old) from Florida were examined for endoparasites between 1998 and 2003. Eleven species of helminths were found (8 nematodes, 2 trematodes, and 1 acanthocephalan). The most prevalent helminths were Ancylostoma caninum (64%), Macracanthorhynchus ingens (36%), Strongyloides sp. (27%), Baylisascaris transfuga (23%), and A. tubaeforme (14%). New host records include A. tubaeforme and Brachylaima virginianum. This is the first report of B. transfuga in black bears from Florida.     

Reevaluation of the systematic status of Cotylotretus grandis (Digenea: Psilostomidae) with new morphological data

The digenetic trematode Cotylotretus grandis is redescribed on the basis of 130 specimens recovered from the body cavity and small intestine of 5 roseate spoonbills Ajaia ajaja (Aves, Ciconiiformes, Threskiornithidae) captured in the Pantanal do Mato Grosso, Brazil. The spoonbill A. ajaja is the only host recorded for specimens of C. grandis since 1819, when the species was proposed by Rudolphi as Distoma grande. The synonymy of Mesaulus Braun, 1902, with Cotylotretus Odhner, 1902, is discussed and confirmed after morphological analysis of the specimens.     

Larva migrans by Baylisascaris transfuga: fatal neurological diseases in Mongolian jirds, but not in mice

Raccoon roundworms (Baylisascaris procyonis) and other Baylisascaris species cause patent or latent larva migrans (LM) in a variety of mammals and birds, including humans. It is not clear whether LM by Baylisascaris transfuga, roundworms of bears, is associated with clinical neurological disorders. To clarify this issue, ICR and BALB/c mice as well as Mongolian jirds (Meriones unguiculatus) were orally inoculated with 2,000-5,000 embryonated eggs of B. transfuga. In mice, the ascarid caused symptomatic LM of limited extent and duration, whereas the infection was fatal in jirds; i.e., they exhibited general signs such as severe depression and emaciation on days 8-11 postinfection (PI) and died, or they developed progressive and fatal neurological disorders after day 14 PI. Histological examination showed B. transfuga larvae in the brain of all mice and jirds examined, and the larvae collected from them developed to a size comparable with that of B. procyonis. There existed, however, critical differences in host reactions against larvae localized in the brain of mice and jirds; B. transfuga larvae found in mice were surrounded by granulomatous reactions and immobilized, whereas larvae found in jirds were free from any host reaction and mobile, causing extensive malacia.     

Granulomatous peritonitis in a European brown bear caused by Baylisascaris transfuga

We report a case of granulomatous peritonitis due to Baylisascaris transfuga in a young male European brown bear (Ursus arctus). At necropsy, there were extensive abdominal adhesions and extensive granulomatous tissue on the peritoneum and liver capsule. In the gastrointestinal tract, there were 58 nematodes that were identified as Baylisascaris transfuga using light and scanning electron microscopy.     

New species of Prodistomum Linton, 1910 (Digenea: Lepocreadiidae) from the longtail bass, Hemanthias leptus (Ginsburg, 1952) in the Bay of Campeche, Gulf of Mexico

Prodistomum lichtenfelsi n. sp. (Digenea: Lepocreadiidae) is described; it was obtained from the intestine of the longtail bass, Hemanthias leptus (Ginsburg), collected from the Bay of Campeche in the Gulf of Mexico. This is the first record of a parasite from this host. Prodistomum lichtenfelsi n. sp. is similar to P. hynnodi, P. menidiae, and P. waltairensis in that it possesses a prepharynx that is distinctly shorter (153 microm [110-210] long) than the combined length of the esophagus (163 microm [110-220] long) and the pseudoesophagus (137 microm [120-170] long), but it differs from them in having an excretory vesicle that extends into the forebody, a smooth ovary and testes, and vitellaria that extend to the posterior level of the esophagus. An updated key to the 12 nominal species within Prodistomum is given, and the diagnosis of the genus is emended to include species possessing a sinuous external seminal vesicle.     

Seasonal changes in the prevalence of ova of Diphyllobothrium ursi and Baylisascaris transfuga in the feces of the black bear (Ursus americanus)

An analysis of 114 samples of feces from black bears (Ursus americanus) from La Verendrye Park, Quebec revealed that the prevalence of eggs of Diphyllobothrium ursi and Baylisascaris transfuga varied seasonally. D. ursi ova were most prevalent during the summer and fall and at their lowest in spring while the converse was true for B. transfuga. This phenomenon possibly is associated with the cessation of feeding during the winter denning of black bears.     

Comparative efficacy of ivermectin and levamisole for reduction of migrating and encapsulated larvae of Baylisascaris transfuga in mice

The comparative efficacy of 2 anthelmintics (ivermectin and levamisole) against Baylisascaris transfuga migrating and encapsulated larvae was studied in mice. A total of 60 BALB/c mice inoculated each with about 1,000 embryonated B. transfuga eggs were equally divided into 6 groups (A-F) randomly. Mice of groups A and B were treated with ivermectin and levamisole, respectively, on day 3 post-infection (PI). Mice of groups A-C were killed on day 13 PI. Similarly, groups D and E were treated with ivermectin and levamisole, respectively, on day 14 PI, and all mice of groups D-F were treated on day 24 PI. The groups C and F were controls. Microexamination was conducted to count the larvae recovering from each mouse. The percentages of reduction in the number of migrating larvae recovered from group A (ivermectin) and B (levamisole) were 88.3% and 81.1%, respectively. In addition, the reduction in encapsulated larvae counts achieved by ivermectin (group D) and levamisole (group E) was 75.0% and 49.2%, respectively. The results suggested that, to a certain extent, both anthelmintics appeared to be more effective against migrating larvae than encapsulated larvae. However, in the incipient stage of infection, ivermectin may be more competent than levamisole as a larvicidal drug for B. transfuga.     

Biochemical and immunological systematics of some ascaridoid nematodes: genetic divergence between congeners

Vertical starch gel electrophoresis and trefoil immunodiffusion were used to study the systematics of some ascaridoid nematodes. Within the Ascarididae, the time scale of divergence was too great for intergeneric electrophoretic comparisons. Congeneric electrophoretic comparisons of Baylisascaris procyonis (host--raccoon) versus Baylisascaris transfuga (host--black bear), and Toxocara canis (host--domestic dog) versus Toxocara cati (host--domestic cat) yielded Nei genetic distance coefficients of 1.21 and 1.55, respectively. Estimates of times of divergence made from 1 electrophoretic clock calibration suggest that the Baylisascaris species have not shared a common ancestor for 25 million years (Myr), and that the Toxocara species diverged 33 Myr ago. The Baylisascaris divergence estimate corresponds to host-family divergence estimates based on immunological and paleontological evidence, which suggests that cospeciation has occurred. In contrast to this, Ascaris suum (host--pig) and Ascaris lumbricoides (host--human) have a distance coefficient of 0.09. This indicates that these species diverged comparatively recently and may represent a case of host range expansion. Trefoil immunodiffusion comparisons of ascaridoid albumins yielded reactions of identity for A. suum, A. lumbricoides, Parascaris equorum, B. procyonis, B. transfuga, T. canis, and T. cati. This confirms that these taxa are members of a monophyletic group.     

Influence of the phase of the number and demographic structure of the water vole population on its infection by helminthes

In this work we have analyzed results of the long-term investigations of the helminthes distribution in the various demography groups of the water vole population (Arvicola terrestris L.) in North Baraba (Novosibirsk region). The data on the dominant parasites of these rodents: trematodes Notocotylus noyeri (Joyeux, 1922), cestodes Limnolepis transfuga Spassky et Merkuscheva, 1967, nematodes Capillaria wioletti Ruchljadeva, 1950, Longistriata minuta (Dujarden, 1845) and Heligmosomum costellatum (Dujarden, 1845) have shown that the number of parasites in biocenosis are connected with different factors, such as the demographic structure of the host population, the alternation of hosts number and conditions of the environment (dry and damp phases of the climatic cycle). In the dry phase the main parasitize load N. noyeri, L. transfuga and C. wioletti connects with the breeding group; in the damp period - with immature rodents. Independently of the phase climatic cycle and the density of the water vole population the great bulk of nematodes L. minuta and H. costellatum was uncovered of the immature individuals. In any case the number of helminthes changed synchronously with such of the its host.     

Helminths recovered from black bears in the Peace River region of northwestern Alberta.

A total of 91 free-ranging black bears (Ursus americanus) from the Peace River region of northwestern Alberta was examined for helminths. Four species, Baylisascaris transfuga, Taenia krabbei, Taenia hydatigena and Dirofilaria ursi, were found. None of the bears was heavily infected. Results are compared with other similar North American surveys.     

Parasites of black bears of the Lake Superior region.

Parasites collected from free-ranging black bears, Ursus americanus Pallas, 1780, from northeastern Minnesota or northern Michigan include the dog tick, Dermacentor variabilis (Say, 1821), the winter tick, D. ALBIPICTUS (Packard, 1869), a louse, Trichodectes pinguis euarctidoes Hopkins, 1954, an ascarid worm, Baylisascaris transfuga (rudolphi, 1819), a filarial worm, Dirofilaria ursi Yamaguti, 1941, taeniid tapeworms, and unidentified fleas. The broad fish tapeworm, Diphyllobothrium latum (linnaeus, 1785), was reported to be common in man and black bears in northeastern Minnesota earlier in this century, but now it apparently is uncommon in black bears in norther Wisconsin. Cannibalism of carcasses is common in the black bear and may play a major role in the transmission of Trichinella.     

Migration behaviour and pathogenesis of five ascarid nematode species in the Mongolian gerbil Meriones unguiculatus

To understand the characteristic features of the Mongolian gerbil, Meriones unguiculatus, as an animal model of ascarid infections, the migration behaviour and pathogenesis of larvae were investigated in experimentally infected gerbils. Embryonated eggs from each of Toxocara canis, Baylisascaris procyonis, B. transfuga, Ascaris suum, and A. lumbricoides were orally inoculated into gerbils and larvae were recovered from various organs at designated periods. In T. canis-infected gerbils, larvae were present in the liver 3 days after infection and in the skeletal muscle and brain via the heart and lungs at a similar rate. In B. procyonis- and B. transfuga-infected gerbils, larvae were present in the lungs within 24 h after infection, with some having reached the brain by that time. After 24 h, larvae of B. procyonis tended to accumulate in the brain, while those of B. transfuga accumulated in skeletal muscles. In A. suum- and A. lumbricoides-infected gerbils, larvae remained in the liver on day 5 post-infection and elicited pulmonary haemorrhagic lesions, which disappeared 7 days after initial infection. Thereafter, no larvae of any type were recovered. Ocular manifestations were frequently observed in T. canis- and B. procyonis infected gerbils, but were rare in B. transfuga-infected gerbils. In the cases of A. suum and A. lumbricoides, migration to the central nervous system and eyes was extremely rare, and larvae had disappeared by 2 weeks post-infection. Fatal neurological disturbances were observed in B. procyonis-infected gerbils, whereas irreversible non-fatal neurological symptoms were observed in the case of B. transfuga.     

Ecto- and endoparasites of the black bear in northern Wisconsin

Parasites collected from free-ranging black bears, Ursus americanus, in northern Wisconsin included Dermacentor variabilis, D. albipictus, Ixodes scapularis, Demodex sp., Trichodectes pinguis euarctidos, Baylisascaris transfuga and Dirofilaria ursi. Mange, possibly caused by the Demodex sp., also was observed. Dental caries were common and periodontal disease was observed in one animal.     

Studies on endoparasites of the black bear (Ursus americanus) in the southeastern United States.

Examination of 53 black bears (Ursus americanus) from six states in the southeastern United States revealed at least 17 species of endoparasites, including Sarcocystis sp., Spirometra mansonoides (spargana), Macracanthorhynchus ingens, Ancylostoma caninum, Arthrocephalus lotoris, Baylisascaris transfuga, Capillaria aerophila, Capillaria putorii, Crenosoma sp., Cyathospirura sp., Dirofilaria immitis, Gnathostoma sp., Gongylonema pulchrum, microfilariae, Molineus barbatus, Physaloptera sp. and Strongyloides sp. Twelve of these represent new host records for black bear, and two are considered to be new species. Data are presented on prevalence, intensity and geographic distribution of each species. Pathologic effects were associated with infections of spargana of S. mansonoides and adults of C. aerophilia.     

Complete mitochondrial genomes of Baylisascaris schroederi, Baylisascaris ailuri and Baylisascaris transfuga from giant panda, red panda and polar bear

Roundworms of the genus Baylisascaris are the most common parasitic nematodes of the intestinal tracts of wild mammals, and most of them have significant impacts in veterinary and public health. Mitochondrial (mt) genomes provide a foundation for studying epidemiology and ecology of these parasites and therefore may be used to assist in the control of Baylisascariasis. Here, we determined the complete sequences of mtDNAs for Baylisascaris schroederi, Baylisascaris ailuri and Baylisascaris transfuga, with 14,778 bp, 14,657 bp and 14,898 bp in size, respectively. Each mtDNA encodes 12 protein-coding genes, 22 transfer RNAs and 2 ribosomal RNAs, typical for other chromadorean nematodes. The gene arrangements for the three Baylisascaris species are the same as those of the Ascaridata species, but radically different from those of the Spirurida species. Phylogenetic analysis based on concatenated amino acid sequences of 12 protein-coding genes from nine nematode species indicated that the three Baylisascaris species are more closely related to Ascaris suum than to the three Toxocara species (Toxocara canis, Toxocara cati and Toxocara malaysiensis) and Anisakis simplex, and that B. ailuri is more closely related to B. transfuga than to B. schroeder. The determination of the complete mt genome sequences for these three Baylisascaris species (the first members of the genus Baylisascaris ever sequenced) is of importance in refining the phylogenetic relationships within the order Ascaridida, and provides new molecular data for population genetic, systematic, epidemiological and ecological studies of parasitic nematodes of socio-economic importance in wildlife.     

Physicochemical characterization and monoclonal and polyclonal antibody recognition of Baylisascaris procyonis larval excretory-secretory antigens

Baylisascaris procyonis larval excretory-secretory (ES) antigens consisted of complex glycoproteins ranging from 10 kDa to over 200 kDa as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis and lectin binding. Five monoclonal antibodies (Bapr1-Bapr5) produced against B. procyonis ES antigens were assayed by western blotting with larval ES antigens from B. procyonis, Baylisascaris melis, Baylisascaris transfuga, Ascaris suum, and Toxocara canis. Bapr1 and Bapr2 recognized periodate-sensitive epitopes on 14-kDa ES components of B. procyonis, B. melis, and B. transfuga, whereas Bapr4 and Bapr5 recognized periodate-resistant epitopes present on 55-kDa ES components of B. procyonis and B. melis. Bapr3 primarily recognized periodate-resistant epitopes on 33-45-kDa components of B. procyonis and B. melis ES. Heterologous rabbit antisera cross-reacted with many B. procyonis ES antigens on western blots, but recognition of the 33-45-kDa components was genus-specific. Normal human sera and T. canis-positive human sera also cross-reacted with many B. procyonis ES antigens, including those of 33-45 kDa. However, periodate oxidation markedly decreased cross-reactions and allowed for differential immunodiagnosis of B. procyonis versus T. canis. These studies demonstrated that antibody recognition of carbohydrate epitopes on ES components is an important cause of cross-reactions in antibody detection assays. Recognition of periodate-resistant (protein) epitopes on the 33-45-kDa B. procyonis ES components appears to be useful for genus-specific immunodiagnosis of larva migrans caused by Baylisascaris spp.     

Waterbirds (other than Laridae) nesting in the middle section of Laguna Cuyutlán, Colima, México

Laguna de Cuyutlán, in the state of Colima, Mexico, is the only large coastal wetland in a span of roughly 1150 km. Despite this, the study of its birds has been largely neglected. Between 2003 and 2006 we assessed the waterbirds nesting in the middle portion of Laguna Cuyutlán, a large tropical coastal lagoon, through field visits. We documented the nesting of 15 species of non-Laridae waterbirds: Neotropic Cormorant (Phalacrocorax brasilianus), Tricolored Egret (Egretta tricolor), Snowy Egret (Egretta thula), Little Blue Heron (Egretta caerulea), Great Egret (Ardea alba), Cattle Egret (Bubulcus ibis), Black-crowned Night-heron (Nycticorax nycticorax), Yellow-crowned Night-heron (Nyctanassa violacea), Green Heron (Butorides virescens), Roseate Spoonbill (Platalea ajaja), White Ibis (Eudocimus albus), Black-bellied Whistling-duck (Dendrocygna autumnalis), Clapper Rail (Rallus longirostris), Snowy Plover (Charadrius alexandrinus), and Black-necked Stilt (Himantopus mexicanus). These add to six species of Laridae known to nest in that area: Laughing Gulls (Larus atricilla), Royal Terns (Thalasseus maximus), Gull-billed Terns (Gelochelidon nilotica), Forster's Terns (S. forsteri), Least Terns (Sternula antillarum), and Black Skimmer (Rynchops niger), and to at least 57 species using it during the non-breeding season. With such bird assemblages, Laguna Cuyutlán is an important site for waterbirds, which should be given conservation status.     

Population Genetic Study of Mitochondrial DNA in Roseate Spoonbill (Aves; Platalea ajaja) Breeding Colonies from the Pantanal Wetlands, Brazil

Five breeding colonies of the Roseate spoonbill (Aves: Platalea ajaja) from two Brazilian wetland areas (Pantanal and Taim marshes) were sampled, and domain I of the mitochondrial DNA control region (483 bp) was sequenced in 50 birds. The average haplotype diversity (h = 0.75, s = 0.071) and average nucleotide diversity (pi = 0.004, s = 0.003) were evaluated, and nonsignificant differences were found among the colonies studied. The lack of differentiation among breeding colonies revealed by AMOVA analysis was explained either as a consequence of high gene flow or recent expansion. The significantly negative results of the neutrality tests (Fu's F ( s ) = -23.271, P < 0.01; Tajima's D = -1.941, P < 0.01) associated with the star shape of the haplotype tree and mismatch distribution data are evidence supporting the idea that these populations underwent a recent demographic expansion in the Pantanal region. The average time since the expansion is estimated to be 25,773 years, and this agrees with a period of increased moisture that occurred during the last glacial period.     

Phylogenetic study of Baylisascaris schroederi isolated from Qinling subspecies of giant panda in China based on combined nuclear 5.8S and the second internal transcribed spacer (ITS-2) ribosomal DNA sequences

The nuclear ribosomal DNA (rDNA) region spanning 5.8S rDNA and the second internal transcribed spacer (ITS-2) of Baylisascaris schroederi isolated from the Qinling subspecies of giant panda in Shaanxi Province, China were amplified and sequenced. Sequence variations in the two rDNA regions within B. schroederi and among species in the family Ascarididae were examined. The lengths of B. schroederi 5.8S and ITS-2 rDNA sequences were 156 bp and 327 bp, respectively, and no nucleotide variation was found in these two rDNA regions among the 20 B. schroederi samples examined, and these ITS-2 sequences were identical to that of B. schroederi isolated from giant panda in Sichuan province, China. The inter-species differences in 5.8S and ITS-2 rDNA sequences among members of the family Ascarididae were 0-1.3% and 0-17.7%, respectively. Phylogenetic relationships among species in the Ascarididae were re-constructed by Bayesian inference (Bayes), maximum parsimony (MP), and maximum likelihood (ML) analyses, based on combined sequences of 5.8S and ITS-2 rDNA. All B. schroederi samples clustered together and sistered to B. transfuga with high posterior probabilities/bootstrap values, which further confirmed that nematodes isolated from the Qinling subspecies of giant panda in Shaanxi Province, China represent B. schroederi. Because of the large number of ambiguously aligned sequence positions (difficulty of inferring homology by positions), ITS-2 sequence alone is likely unsuitable for phylogenetic analyses at the family level, but the combined 5.8S and ITS-2 rDNA sequences provide alternative genetic markers for the identification of B. schroederi and for phylogenetic analysis of parasites in the family Ascarididae.