Geographic distribution of the muscle-dwelling nematode Parelaphostrongylus odocoilei in North America, using molecular identification of first-stage larvae

Molecular identification of dorsal-spined larvae (DSL) from fecal samples indicates that the protostrongylid parasite Parelaphostrongylus odocoilei occupies a broader geographic range in western North America than has been previously reported. We analyzed 2,124 fecal samples at 29 locations from thinhorn sheep (Ovis dalli dalli and O. d. stonei), bighorn sheep (Ovis canadensis canadensis and O. c. californiana), mountain goats (Oreamnos americanus), woodland caribou (Rangifer tarandus caribou), mule deer (Odocoileus hemionus hemionus), and black-tailed deer (O. h. columbianus). The DSL were recovered from populations of thinhorn sheep south, but not north, of the Arctic Circle, and they were not recovered from any of the bighorn sheep populations that we examined. In total, DSL were recovered from 20 locations in the United States and Canada (Alaska, Yukon Territory, Northwest Territories, British Columbia, Alberta, and California). The DSL were identified as P. odocoilei by comparing sequences of the second internal transcribed spacer (ITS2) region of ribosomal RNA among 9 protostrongylid species validated by adult comparative morphology. The ITS2 sequences were markedly different between Parelaphostrongylus and other protostrongylid genera. Smaller fixed differences served as diagnostic markers for the 3 species of Parelaphostrongylus. The ITS2 sequences (n = 60) of P. odocoilei were strongly conserved across its broad geographic range from California to Alaska. Polymorphism at 5 nucleotide positions was consistent with multiple copies of the ITS2 within individual specimens of P. odocoilei. This work combines extensive fecal surveys, comparative morphology, and molecular diagnostic techniques to describe comprehensively the host associations and geographic distribution of a parasitic helminth.     

Congruent and synchronic patterns in biogeography and speciation among seabirds, pinnipeds, and cestodes.

Congruence in biogeographic patterns among diverse assemblages of taxa indicates uniformity in the historical determinants of biotic distributions. Comparisons of host and parasite phylogenies and the elucidation of distributional area relationships are requisite components of analyses in historical biogeography. Host-parasite associations with broad geographic ranges are often archaic and have been structured largely by coevolutionary processes. In contrast, the origins and radiation of the primary cestode faunas of some seabirds (Alcataenia spp./Alcidae) and pinnipeds (Anophryocephalus spp./Phocidae and Otariidae) are associated with colonization. These young colonizing faunas, in the Holarctic Region, were influenced by a common history during the late Pliocene and Pleistocene epochs. Periodic range contraction, with isolation in refugial centers, and subsequent expansion into postglacial habitats for hosts and parasites coincided with the cyclic pattern of stadials and interstadials. During the past 2-3 million years following colonization, these dramatic climatic fluctuations strongly influenced the continuity of ecological associations in marine habitats and appear to have been the determinants of congruent and synchronic patterns of speciation among these disparate taxa of marine homeotherms and eucestodes.     

Estrogen dynamics in the female rhesus monkey

The metabolic clearance rates (MCR) and interconversions [( rho]BB) values for estrone (E1) and estradiol (E2) in female rhesus (Macaca mulatta) monkeys on Days 9, 14, and 23 of the menstrual cycle were measured using constant infusions of [3H] estradiol and [14C] estrone. The menstrual cycles in these monkeys were reproduced by using Silastic capsules of E2 and progesterone after bilateral ovariectomy. The serum levels of E2 and progesterone were measured by radioimmunoassay and were similar to those for the intact menstrual cycle. The MCR of E2 on Day 14 (52.8 +/- 6.8 l/day/kg) was significantly greater (p less than 0.05) than that measured on Day 9 (31.1 +/- 3.6 l/day/kg) or Day 23 (35.4 +/- 2.1 l/day/kg). The MCR of E1 was also different (p less than 0.05) on Day 14 (77.6 +/- 14.9 l/day/kg) compared to the values on Days 9 and 23 (50.2 +/- 4.9 and 48.2 +/- 3.9 l/day/kg, respectively. There was no change in percentage of free E2, percentage of albumin-bound E2, or sex hormone-binding globulin levels on those 3 days of the cycle. The interconversions between E2 and E1 were not influenced by the day of the cycle. We conclude that the high levels of E2 occurring at the time of the E2 peak result in increases in the MCRs of both E2 and E1 that are not associated with changes in the pattern of protein-binding or in the activity of the 17 beta-hydroxy steroid dehydrogenase.     

Temporal and spatial mosaics: deep host association and shallow geographic drivers shape genetic structure in a widespread pinworm,Rauschtineria eutamii (Nematoda: Oxyuridae)

Climate and host demographic cycling often shape both parasite genetic diversity and host distributions, processes that transcend a history of strict host–parasite association. We explored host associations and histories based on an evaluation of mitochondrial and nuclear sequences to reveal the underlying history and genetic structure of a pinworm, Rauschtineria eutamii, infecting ten species of western North American chipmunks (Rodentia:Tamias, subgenus Neotamias). Rauschtineria eutamii contains divergent lineages influenced by the diversity of hosts and variation across the complex topography of western North America. We recovered six reciprocally monophyletic R. eutamii mitochondrial clades, largely supported by a multilocus concordance tree, exhibiting divergence levels comparable with intraspecific variation reported for other nematodes. Phylogenetic relationships among pinworm clades suggest that R. eutamii colonized an ancestral lineage of western chipmunks and lineages persisted during historical isolation in diverging Neotamias species or species groups. Pinworm diversification, however, is incongruent and asynchronous relative to host diversification. Secondarily, patterns of shallow divergence were shaped by geography through events of episodic colonization reflecting an interaction of taxon pulses and ecological fitting among assemblages in recurrent sympatry. Pinworms occasionally infect geographically proximal host species; however, host switching may be unstable or ephemeral, as there is no signal of host switching in the deeper history of R. eutamii.     

Alcataenia atlantiensis n. sp. (Dilepididae) from the razorbill (Alca torda Linnaeus) in the eastern North Atlantic basin

A new species of Alcataenia is described from razorbills Alca torda Linnaeus from the southern region of the North Sea in the coastal waters of Belgium. It differs from known species of the genus in having 18–20 rostellar hooks measuring 63–74 m in length. Other attributes include a cirrus-sac 145–228 m in length, 36–49 testes and a vitelline gland measuring 114–202 × 59–112 m. This is the first species of Alcataenia described from razorbills and appears to be the only member of the genus which is endemic to the North Atlantic basin.     

Biodiversity and ecology of epilithic diatoms in the Agnéby River,Ivory Coast

The ecology and taxonomy of the epilithic diatom flora of the Agnéby River, Ivory Coast were studied in 2012. Ten sites were investigated and diatoms were sampled on glass slides immersed for a period of 30 days during the wet and dry seasons. Physico-chemical parameters were measured at each site while sampling diatoms. Five taxa were largely dominant: Planothidium comperei CE Wetzel, N’Guessan and Tison-Rosebery, Eolimna minima (Grunow) Lange-Bertalot, Planothidium piaficum (JR Carter and Denny) CE Wetzel and Ector, Cocconeis schroederi Foged and Cocconeis scutellum var. parva (Grunow in Van Heurck) Cleve. Electrical conductivity, temperature, dissolved oxygen, nitrite and phosphorus were found to influence the distribution of taxa.     

Emended description and redetermination of Sarwaria caballeroi n. comb. (nematoda: Ostertagiinae) with details of the synlophe and esophageal characters

Among genera of the ostertagiine nematodes, structural attributes of Spiculopteragia caballeroi are consistent with criteria that diagnose the genus Sarwaria. Specifically, the following characters are compatible with referral to this genus: (1) species characterized by monomorphic males; (2) tapering lateral synlophe in the cervical zone; (3) minuscule, thornlike cervical papillae; (4) length of Ray "4" < Ray "5"; (5) relatively thick or robust Ray "4"; (6) a substantially reduced dorsal lobe and dorsal ray that are disposed or curved ventrally relative to Rays "8"; and (7) a broad, laterally inflated dorsal lobe. Consequently, we propose Sarwaria caballeroi n. comb., and we provide further validation for the genus Sarwaria. Additionally, we propose that the ostertagiines are represented by 12 valid genera, including those characterized by a bursal formula of 2-2-1 (Cervicaprastrongylus, Hyostrongylus, Mazamastrongylus, Spiculopteragia, and Teladorsagia in addition to Sarwaria), and those in which the lateral rays describe a 2-1-2 pattern (Camelostrongylus, Longistrongylus, Marshallagia, Orloffia, Ostertagia, and Pseudomarshallagia).     

Controlled release devices for the delivery of anthelmintics in cattle

Control of cattle helminths is not so much a problem of drug choice, but of drug delivery and livestock management. Several effective anthelmintics are available for domestic livestock, but their efficiency in limiting infection and disease attributed to important parasites such as Ostertagia and Haemonchus has been mainly due to good management practice and strategically timed treatment based on detailed epizootiological studies of parasite transmission. In most situations, treated animals remain fully susceptible to reinfection if continually grazed on contaminated pastures, and this is the rationale behind techniques for continuous or multiple treatment with anthelmintics. In response to these treatment requirements, the animal health industry has developed controlled release devices, or boluses, that can be implanted orally into the rumen (Fig. 1) to release anthelmintics over an extended period - either in a delayed or pulsed fashion. In this article, Gary Zimmerman and Eric Hoberg discuss same of the most promising of such devices.