Blood parasites of amphibians from Algonquin Park, Ontario

During a 5 wk period beginning May 25, 1983, 329 amphibians, which included specimens of Rana catesbeiana Shaw, Rana clamitans Latreille, Rana septentrionalis Baird, Rana sylvatica LeConte, Hyla crucifer Wied, Bufo americanus Holbrook, and Plethodon cinereus Green, from Lake Sasajewun, Algonquin Park, Ontario, Canada were examined for blood parasites. The prevalences of species of Trypanosoma, Haemogregarina, Lankesterella, Babesiasoma, and Thrombocytozoons in these amphibians were determined. Two species of microfilaria (probably Foleyella spp.) and two intraerythrocytic forms, inclusions of an icosahedral cytoplasmic DNA virus (ICDV) and groups of rickettsial organisms, were also observed. The following are new host records: Trypanosoma ranarum (Lankester, 1871) in B. americanus; Trypanosoma ranarum (Lankester, 1871) in R. sylvatica; Trypanosoma pipientis Diamond, 1950, Babesiasoma stableri Schmittner and McGhee, 1961 and Thrombocytozoons ranarum Tchacarof, 1963 in R. septentrionalis. The aquatic frogs generally showed a much higher prevalence of infection with blood parasites than the terrestrial frogs, toads and salamanders, which is suggestive of an aquatic vector. The leech Batracobdella picta Verrill, 1872, which was found on many of the aquatic frogs, is the most likely vector in the study area. Also, an increasing prevalence of parasites was noted with increasing sizes (ages) of Rana clamitans and R. catesbeiana suggesting that longer exposure to water makes these species more likely to acquire blood parasites. The presence of Trypanosoma ranarum in B. americanus appeared to coincide with their attainment of sexual maturity.     

A survey of blood and other tissue parasites of leopard frogs Rana pipiens in the United States.

In a survey of blood and other tissue parasites from 137 leopard frogs, Rana pipiens complex, purchased from 13 commercial vendors in 8 states in the United States, Trypanosoma pipientis was found in 2 R. p. berlandieri, Toxoplasma ranae in 1 R. pipiens, Isospora lieberkuehni in 1 leopard frog, Haemogregarina magna in 44, Lankesterella minima in 3, Leptotheca ohlmacheri in 3 and microfilariae of Foleyella sp. in 6. The report of I. lieberkuehni is presumably a new host record. Haemogregarina temporariae (N?ller,, 1920) nov. comb. is established as a new combination for Nematopsis temporariae.     

Range-wide phylogeographic analysis of the spotted frog complex (Rana luteiventris and Rana pretiosa) in northwestern North America

The dynamic geological and climatic history of northwestern North America has made it a focal region for phylogeography. We conducted a range-wide phylogeographic analysis of the spotted frog complex (Rana luteiventris and Rana pretiosa) across its range in northwestern North America to understand its evolutionary history and the distribution of clades to inform conservation of R. pretiosa and Great Basin R. luteiventris, candidates for listing under the US Endangered Species Act. Mitochondrial DNA sequence data from a segment of the cytochrome b gene were obtained from 308 R. luteiventris and R. pretiosa from 96 sites. Phylogenetic analysis revealed one main R. pretiosa clade and three main R. luteiventris clades, two of which overlapped in southeastern Oregon. The three R. luteiventris clades were separated from each other by high levels of sequence divergence (average of 4.75-4.97%). Two divergent clades were also uncovered within the Great Basin. Low genetic variation in R. pretiosa and the southeastern Oregon clade of R. luteiventris suggests concern about their vulnerability to extinction.     

Search for the trematode Prouterina wescotti in black bears in Oregon.

Forty-six heads of free-ranging black bears (Ursus americanus) collected in May and June of 1995 and 1996 from Oregon (USA) were examined for the trematode Prouterina wescotti and other parasites. Only Sarcocystis sp. was detected in two adult male bears. Prouterina wescotti has been found only once previously in one black bear from Idaho (USA); its normal definitive host remains unknown.     

Blood parasites in sage-grouse from Nevada and Oregon

Peripheral blood smears from 196 adult and yearling female greater sage-grouse (Centrocercus urophasianus) were examined for blood parasites (167 from the breeding and 29 from the brood-rearing season) to determine prevalence of blood parasites, to attempt to correlate infection with chick survival, and to establish base-line values of prevalence in sage-grouse from Nevada and Oregon (USA). Birds were captured and released on two study areas during 1999-2001; Sheldon National Wildlife Refuge (SNWR) in northwestern Nevada, and Hart Mountain National Antelope Refuge (HMNAR) in southeastern Oregon. Birds from a third study area, Beaty's Butte grazing allotment (BB) in southeastern Oregon, were sampled in 2000 and 2001. Overall, 19 birds (10%) were positive for Leucocytozoon lovati (= L. bonasae), 1 (0.5%) for Plasmodium pedioecetii, and 2 (1%) for microfilariae. Although prevalence of L. lovati on HMNAR was 39% during the breeding season in 1999 and 100% during the brood-rearing season in 2000, statistically, prevalence of L. lovati among study areas and years was not different. However, there were statistical differences between capture periods. Overall, 31% of the hens were positive for L. lovati during the brood-rearing season compared to 6% during the breeding season. There was no difference in packed cell volume between infected and non-infected birds and no difference between age-classes. However, mean sage-grouse productivity on HMNAR was higher (1.6 chicks/hen) for non-infected (n = 10) compared to infected hens (0.7 chicks/hen; n = 7), during 1999. Based on these limited observations on HMNAR in 1999, the possible effects that L. lovati may have on young sage-grouse could be detrimental to sage-grouse populations in Nevada and Oregon.     

Population dynamics of the threatened Oregon spotted frog before and after drought mitigation

Amphibians are among the most sensitive taxa to climate change, and species inhabiting arid and semiarid landscapes at the extremes of their range are especially vulnerable to drought. The Jack Creek, Oregon, USA, population of Oregon spotted frogs (Rana pretiosa) faces unique challenges because it occupies the highest elevation site in the species' extant range and one that has been transformed by loss of American beavers (Castor canadensis), which historically maintained open water. We evaluated the effects of drought mitigation (addition of excavated ponds) on relationships between local and regional water availability, inactive legacy beaver dams, and Oregon spotted frog population dynamics in the Jack Creek system. We conducted egg mass surveys and capture-mark-recapture sampling at a treatment reach with excavated ponds and 3 reference reaches over 13 years; surveys spanned a period before and after pond excavation at the treatment and 1 primary comparison reference reach. We analyzed data using a combination of robust design capture-mark-recapture estimators and generalized linear mixed models to characterize population dynamics. Adult Oregon spotted frog survival was approximately 19.5% higher at the treatment reach than the primary reference reach during the study period. Annual survival was most strongly associated with late summer vegetation greenness, a proxy for water availability, and males had higher survival than females. Among the 4 study reaches, the treatment reach consistently had higher late summer vegetation greenness, and the hydrology functioned more independently of regional precipitation patterns relative to the reference reaches; however, these dynamics were not linked to pond excavation. Breeding was concentrated in 2 legacy beaver ponds that were deepened by excavation during the study compared to an unexcavated beaver pond, 2 excavated ponds without legacy beaver dams, and 9 reference ponds. These results point to the benefit of enhancing existing beaver structures and indicate that management actions aimed at maintaining surface water for breeding in spring and saturated soils and ponded water for adults in late summer would benefit this unique population of Oregon spotted frogs in the face of drought.     

The blood parasites of anurans from Costa Rica with reflections on the taxonomy of their trypanosomes

During May 1997, specimens of 7 species of anurans, that included 5 Phrynohyas venulosa Laurenti, 5 Rana forreri Boulenger, 7 Rana vaillanti Brucchi, 6 Eleutherodactylus fitzingeri Schimdt, 4 Smilisca baudinii Duméril and Bibron, 1 Leptodactylus melanonotus, and 3 Bufo marinus Linneaus, from the Guanacaste Conservation Area, Costa Rica were examined for blood parasites. Their hematozoan fauna included intraerythrocytic and intraleukocytic icosahedral viruses, a rickettsia (Aegyptianella sp.), 2 species of Hepatozoon, Lankesterella minima, 2 unknown species of apicomplexans, 9 morphologically distinct types of trypanosomes, and 2 species of microfilariae. Rana vaillanti, the most aquatic species of frog, harbored the most species of parasites. Recent evidence indicates that morphological changes in the highly pleomorphic trypanosomes of anurans from different geographical regions have not kept pace with biochemical (isozyme) and molecular (DNA sequence) changes. Describing new species based solely on bloodstream trypomastigotes is discouraged. Additional criteria described herein should be applied when naming new species of anuran trypanosomes.     

Non-native species impacts on pond occupancy by an anuran

Non-native fish and bullfrogs (Lithobates catesbeianus) are frequently cited as contributing to the decline of ranid frogs in the western United States, so we hypothesized that non-native species, habitat, or a combination of these relate to the probability of local extinction for northern red-legged frogs (Rana aurora) in Oregon, USA. We also hypothesized that the probability of colonization relates to land use, wetland size, or riparian forest. In a 5-yr study, we found no support for an effect of non-native species on northern red-legged frogs. Instead, probability of local extinction decreased with the extent of emergent vegetation and riparian forest. This finding suggests that managers consider the role of habitat when confronting non-native species problems. © 2010 The Wildlife Society.     

Helminth parasites of northern spotted owls (Strix occidentalis caurina) from Oregon

Helminth parasites are reported for the first time from northern spotted owls. Seventy-one percent of a sample of Strix occidentalis caurina from western Oregon was infected. Nematodes (Porrocaecum depressum, Capillaria falconis, Microtetrameres sp. and Synhimantus hamatus) were the most prevalent parasites although cestodes (Paruterina rauschi) and acanthocephalans (Centrorhynchus conspectus) were also represented. There was an association between components of this helminth fauna and the diet of spotted owls which is dominated by small rodents. The occurrence of P. rauschi rather than P. candelabraria in this geographic region and host-species may provide additional support for recognition of a parapatric distribution in the ranges of Paruterina spp. among strigiforms in the Nearctic.     

Helminths of California quail (Callipepla californica) and mountain quail (Oreortyx pictus) in western Oregon

Eighty California quail (Callipepla californica), collected from the E. E. Wilson Wildlife Area near Monmouth, Oregon (USA) during a 22 mo period, were examined for gastrointestinal helminths. Eight birds were infected with three species of nematodes, Heterakis isolonche, Dispharynx nasuta, and Capillaria sp., and two species of cestodes, Rhabdometra odiosa and Davainea sp. Except for D. nasuta, prevalence did not exceed 5% despite mesic conditions in the collection area. Two mountain quail (Oreortyx pictus) were collected from Lane County, Oregon (USA), near Blue River Reservoir; both were infected with the nematode Trichostrongylus tenuis.     

Evidence for host allozymes present on electrophoretic gels of trematode parasites (Digenea: Plagiorchiiformes)

An allozyme analysis of trematode species Glypthelmins californiensis, Glypthelmins quieta, Glypthelmins pennsylvaniensis, Glypthelmins hyloreus, and Haplometrana intestinalis from hosts Rana aurora, Rana clamitans, Hyla crucifer, Pseudacris triseriata, and Rana pretiosa, using starch gel electrophoresis, revealed allozymes for glucose-phosphate isomerase, lactate dehydrogenase, malate dehydrogenase, and isocitrate dehydrogenase that were similar in electrophoretic mobility to host tissue controls. Host allozymes were present on gels for only a fraction of the individual parasite samples examined and could be differentiated from parasite allozymes using host tissue controls. Based on these findings, it is suggested that host samples be included on each electrophoretic gel in genetic studies of parasites to reduce the likelihood of errors due to host enzyme contamination of parasite samples.     

Observations on Lankesterella hylae

SYNOPSIS. Sporozoites of Lankesterella hylae were found in 12 of 13 green tree frogs ( Hyla caerulea ) from Gin Gin, Queensland. The intraerythrocytic sporozoites had two pale-staining vacuoles at the poles of the nucleus and frequently a dome-like protuberance on the concavity of the crescentic protozoon.
Motility was observed in free but not intracellular sporozoites in fresh blood. Locomotion was of a gliding nature, though in addition parasites flexed and extended, and a peristaltic constriction passed backwards along the body of two. One parasite entered and emerged from a red cell, the erythrocyte playing a passive role.
All stages of sporogony were observed in liver smears from a debilitated frog. In araldite sections of the small intestine of another frog, parasites were found in the vacuoles within unidentified cells in the lamina propria, thus suggesting that the parasite's point of entry is possibly the alimentary tract.     

Predation risk and competition effects on the life-history characteristics of larval Oregon spotted frog and larval red-legged frog

We conducted an artificial pond experiment to test hypotheses about the effects of competition and non-lethal predator cues on metamorphic characteristics of sympatric Oregon spotted frogs (Rana pretiosa) and red-legged frogs (Rana aurora) in southwestern British Columbia. Tadpoles were exposed to the presence or absence of one another, two density levels and to the presence or absence of predacious odonate larvae (Aeshna palmata) isolated in enclosures. In the artificial pond study, R. aurora were significantly larger at metamorphosis (12%) and exhibited only slightly longer larval periods when exposed to Aeshna. In the presence of R. pretiosa, they significantly decreased time to metamorphosis, and were significantly larger at metamorphosis (12%) than those reared alone. Rana pretiosa in treatments with R. aurora were somewhat larger at metamorphosis when a non-lethal predator was present, and in treatments where R. pretiosa were alone with a predator tadpole mass at metamorphosis was smaller than those in the absence of Aeshna, but these results were not statistically significant. Both species reduced activity and moved away from the predator in the presence of an enclosed dragonfly larva in the laboratory. Most tadpole mesocosm experiments have found that the trade-off between size and timing of metamorphosis is extremely important to amphibians, but we suggest that the trade-off discussed in traditional amphibian models may not apply to species like R. pretiosa that are exposed to the same gape-limited predators upon reaching metamorphosis.     

Molecular phylogenetics of western North American frogs of the Rana boylii species group

Phylogenetic relationships among frogs of the genus Rana from western North America are investigated using 2013 aligned bases of mitochondrial DNA sequence from the genes encoding ND1 (subunit one of NADH dehydrogenase), tRNA(Ile), tRNA(Gln), tRNA(Met), ND2, tRNA(Trp), tRNA(Ala), tRNA(Asn), tRNA(Cys), tRNA(Tyr), and COI (subunit I of cytochrome c oxidase), plus the origin for light-strand replication (O(L)) between the tRNA(Asn) and tRNA(Cys) genes. The aligned sequences contain 401 phylogenetically informative characters. A well-resolved phylogenetic hypothesis in which the Rana boylii species group (R. aurora, R. boylii, R. cascadae, R. muscosa, and R. pretiosa) is monophyletic is obtained. Molecular sequence divergence suggests that the R. boylii species group is approximately 8 million years old. The traditional hypothesis showing monophyly of the yellow-legged frogs (R. boylii and R. muscosa) is statistically rejected in favor of a hypothesis in which R. aurora, R. cascadae, and R. muscosa form a clade. Reanalyses of published nuclear ribosomal DNA restriction-site data and allozymic data support a monophyletic R. boylii group, but do not effectively resolve relationships among species within this group. Eight populations of R. muscosa form two major clades separated by a biogeographic break in the Sierra Nevada of California. This biogeographic break is broadly concordant with breaks found in four other amphibian and reptilian taxa. The two major clades within R. muscosa are estimated to have diverged approximately 2.2 million years before present. Each of these major clades contains two subgroups showing approximately 1.5 million years divergence, implicating climatic effects of Pleistocene glaciation in vicariance. The four distinct subgroups of R. muscosa separated by at least 1.4 million years of evolutionary divergence are suggested as potential units for conservation.     

Electrophoretic evidence concerning the relationship between Haplometrana and Glypthelmins (Digenea: Plagiorchiiformes)

Analysis of genetic data from a multilocus allozyme study, using cellulose acetate gel electrophoresis, of 2 trematode species, Glypthelmins californiensis Stafford, 1905, and Haplometrana intestinalis Lucker, 1931, from Rana aurora and Rana pretiosa, yielded a Nei's genetic distance coefficient between parasites of 0.70 +/- 0.10. This amount of genetic divergence is characteristic of comparisons between congeneric rather than intergeneric trematode species and supports the conclusion, corroborated by morphology and life history, that H. intestinalis is more closely related to some members of Glypthelmins than to any other species.     

Three New Ranidae Mitogenomes and the Evolution of Mitochondrial Gene Rearrangements among Ranidae Species

Various types of gene rearrangements have been discovered in the mitogenoes of the frog family Ranidae.In this study,we determined the complete mitogenome sequence of three Rana frogs.By combining the available mitogenomic data sets from Gen Bank,we evaluated the phylogenetic relationships of Ranidae at the mitogenome level and analyzed mitogenome rearrangement cases within Ranidae.The three frogs shared an identical mitogenome organization that was extremely similar to the typical Neobatrachian-type arrangement.Except for the genus Babina,the monophyly of each genus was well supported.The genus Amnirana occupied the most basal position among the Ranidae.The[Lithobates+Rana]was the closest sister group of Odorrana.The diversity of mitochondrial gene arrangements in ranid species was unexpectedly high,with 47 mitogenomes from 40 ranids being classified into 10 different gene rearrangement types.Some taxa owned their unique gene rearrangement characteristics,which had significant implication for their phylogeny analysis.All rearrangement events discovered in the Ranidae mitogenomes can be explained by the duplication and random loss model.     

Effect of cattle exclosures on Columbia Spotted Frog abundance

Livestock grazing is an important land use in the western USA and can have positive or negative effects on amphibians. Columbia Spotted Frog (Rana luteiventris) often use ponds that provide water for cattle. We conducted a long-term manipulative study on US Forest Service land in northeastern Oregon to determine the effects of full and partial exclosures that limited cattle access to ponds used by frogs. We found weak evidence of a short-term increase in abundance that did not differ between full and partial exclosures and that diminished with continuing exclusion of cattle. The benefit of exclosures was small relative to the overall decline in breeding numbers that we documented. This suggests that some protection can provide a short-term boost to populations.     

Prevalence of Blood Parasites in Eastern Versus Western House Finches: Are Eastern Birds Resistant to Infection?

The rapid spread of the bacterial disease, Mycoplasma gallisepticum (MG), throughout the introduced range of house finches (Carpodacus mexicanus) in eastern North America, compared to its slower spread through the native western range, has puzzled researchers and highlights the need to understand the relative differences in health state of finches from both populations. We conducted a light-microscope survey of hemoparasites in populations of finches from Arizona (within the western range) and from Alabama (within the eastern range), and compared our estimates of prevalence to published reports from house finches sampled in both ranges. Of the 33 Arizona birds examined, we recorded hematozoan infections in 16 (48.5%) individuals, compared to 1 infected Alabama bird out of 30 birds examined (3.3%). Based on independent surveys of seven western North American and five eastern North American populations of house finches the average prevalence of blood parasites in western populations is 38.8% (±17.9 SD), while the average prevalence within the eastern range is only 5.9% (±6.1 SD). The average rate of infection among all songbirds sampled in the east is 34.2% (±4.8 SD). Thus, our surveys of wild birds as well as previously published observations point to eastern house finches having a much lower prevalence of blood parasite infections than their western counterparts. Combined with the fact that eastern finches also tend to have lower rates of avian pox infections than do western birds (based on a literature review), these observations suggest that eastern birds have either strong resistance to these infections or high susceptibility and associated mortality.     

Modeling Habitat Occupancy of Orange-Crowned Warblers in Managed Forests of Oregon and Washington,USA

Abstract: As part of a habitat management planning process for commercially managed forests, we developed and evaluated habitat occupancy models for the orange-crowned warbler (Vermivora celata), a conservation priority species in Oregon and Washington, USA. We used repeated surveys to classify a random sample of managed conifer stands at the McKenzie, PeEll, and Tolt study sites in western Oregon and Washington as either occupied or unoccupied during 1994–1995. We modeled occupancy and detection probabilities as a function of stand-level habitat characteristics subject to manipulation by management activities. The best-fitting model indicated that orange-crowned warblers were 2 times (95% CI: 0.99-5.1) and 3.8 times (95% CI: 1.5–6.1) as likely to occupy a stand for every 5% increase in evergreen shrub cover and 5-m decrease in canopy lift (ht to lowest live branch), respectively. Management actions that maintain evergreen shrub cover >10% and permit development of low canopy lifts (4–10 m) should promote habitat occupancy by the orange-crowned warbler in commercial forests in western Oregon and Washington.     

Survey of parasites in threatened stocks of coho salmon (Oncorhynchus kisutch) in Oregon by examination of wet tissues and histology

We are conducting studies on the impacts of parasites on Oregon coastal coho salmon (Oncorhynchus kistuch). An essential first step is documenting the geographic distribution of infections, which may be accomplished by using different methods for parasite detection. Thus, the objectives of the current study were to (1) identify parasite species infecting these stocks of coho salmon and document their prevalence, density, and geographic distribution; (2) assess the pathology of these infections; and (3) for the first time, determine the sensitivity and specificity of histology for detecting parasites compared with examining wet preparations for muscle and gill infections. We examined 576 fry, parr, and smolt coho salmon in total by histology. The muscle and gills of 219 of these fish also were examined by wet preparation. Fish were collected from 10 different locations in 2006-2007. We identified 21 different species of parasites in these fish. Some parasites, such as Nanophyetus salmincola and Myxobolus insidiosus, were common across all fish life stages from most basins. Other parasites, such as Apophallus sp., were more common in underyearling fish than smolts and had a more restricted geographic distribution. Additional parasites commonly observed were as follows: Sanguinicola sp., Trichodina truttae , Epistylis sp., Capriniana piscium, and unidentified metacercariae in gills; Myxobolus sp. in brain; Myxidium salvelini and Chloromyxum majori in kidney; Pseudocapillaria salvelini and adult digenean spp. in the intestine. Only a few parasites, such as the unidentified gill metacercariae, elicted overt pathologic changes. Histology had generally poor sensitivity for detecting parasites; however, it had relatively good specificity. We recommend using both methods for studies or monitoring programs requiring a comprehensive assessment of parasite identification, enumeration, and parasite-related pathology.