Norman O. Dronen

Endohelminths from the Brown Pelican, Pelecanus occidentalis, and the American White Pelican, Pelecanus erythrorhynchus, from Galveston Bay, Texas, U.S.A., and Checklist of Pelican Parasites

Abstract Ten species of endohelminths including 2 cestodes, 3 nematodes, and 5 trematodes were collected from 6 American white pelicans, Pelecanus erythrorhynchus, and 22 species of endohelminths including 2 acanthocephalans, 3 cestodes, 4 nematodes, and 13 trematodes were collected from 10 brown pelicans, Pelecanus occidentalis, from the Galveston, Texas, area. A mean of 120 and a range of 4 to 2,134 helminths were present in the American white pelican, and a mean of 57 and a range of 2 to 10,413 helminths were found in the brown pelican. Two cestodes, 3 nematodes, and 3 trematodes were common to both species of pelicans. Parvitaenia ibisae, Tetrabothrius sp., Capillaria sp. represent new host records for the American white pelican, and Echinochasmus cf. donaldsoni, Phagicola macrostoma, and Lyperosomum sp. represent new host records for the brown pelican. Hypotheses for the recent infection of pelicans with species of Bursacetabulus and Bursatintinnabulus along the Gulf coast are discussed.

Two new species of Contracaecum Railliet & Henry, 1912 (Nematoda: Anisakidae), C. fagerholmi n. sp. and C. rudolphii F from the brown pelican Pelecanus occidentalis in the northern Gulf of Mexico.

DNA sequencing of the nuclear ribosomal DNA internal transcribed spacers (ITS) and mitochondrial rrnS and cox2 genes, and analysis of polymorphisms in restriction profiles in the ITS and rrnS, were used to characterise anisakid nematodes belonging to Contracaecum Railliet & Henry, 1912 infecting the brown pelican Pelecanus occidentalis (L.) in Galveston Bay, Texas and Sarasota Bay, Florida. Molecular data led to the detection of two new species: Contracaecum fagerholmi n. sp., which was also supported by clear morphological evidence, and Contracaecum rudolphii F, a new cryptic species within the Contracaecum rudolphii Hartwich, 1964 complex. Bayesian phylogenetic analysis demonstrated that C. fagerholmi and C. rudolphii F form two well-separated clusters, with C. fagerholmi being closely related to Contracaecum bioccai Mattiucci et al., 2008 and C. rudolphii F being included in the C. rudolphii complex. C. fagerholmi can be readily differentiated morphologically from all of its congeners, other than C. microcephalum (Rudolphii 1809) and the five currently recognised members of the C. rudolphii complex (C. rudolphii A, B, C, D and E). C. fagerholmi differs from C. microcephalum in the length of the spicules and the shape of the distal tip of the spicules, and from C. rudolphii (sensu lato) in the shape and size of the ventro-lateral and dorsal lips and by having interlabia which are not distally bifurcate. Further studies are needed to determine which morphological characteristics can be used to distinguish the cryptic species of the C. rudolphii complex in order to assign them with formal names. The recovery of a third species, C. bioccai, from the brown pelican confirms its occurrence in this host and extends its known geographical distribution.

Simulation of population dynamics of the parasite Haematoloechus coloradensis in its three host species: effects of environmental temperature and precipitation

We describe the development and evaluation of a simulation model representing the life cycle of the parasite Haematoloechus coloradensis, and use this model to examine effects of variation in temperature and precipitation on parasite population dynamics. The model consists of four submodels representing: (1) dynamics of parasite eggs in the environment; and infection, parasite development within, and resulting population dynamics of (2) snail, (3) odonate, and (4) frog hosts. Simulated population dynamics and seasonal variation in prevalences of infection for second and definitive hosts generally agreed with field observations. Differences between simulated and observed variation in prevalence for the first intermediate host probably were due to failure of the model to represent effects of temperature on parasite development within snails and parasite-induced host mortality. High precipitation and short summers (favorable conditions for host populations) did not show important effects on prevalences for the three host species in the long term. Simulated effects of low precipitation and extended summers (unfavorable conditions for host species) indicated that temperature had a greater impact on parasite population dynamics than precipitation. Susceptible host abundance was decreased during extended summers to levels below which encounter rate could maintain the parasite population. Overall, results suggest that timing of occurrence of a given disturbance may be as important in determining impact on parasite population dynamics as the specific nature of the disturbance.

Helminths of shorebirds from the Texas Gulfcoast. I. Digenetic trematodes from the long-billed curlew, Numenius americanus.

Trematodes found in 10 Numenius americanus from the Galveston area included Pelmatostomum americanum sp. n. (Echinostomatidae) from the intestine; Paratrema numenii gen. et sp. n. (Philophthalmidae) from the Bursa Fabricii and lower intestine; and the following previously known species, all representing new host records: Maritrema arenaria and Probolocorphye glandulosa (Microphallidae); Lyperosomum oswaldoi and L. sinuosum (Dicrocoeliidae); Cyclocoelum obscurum (Cyclocoelidae); Himasthla rhigedana (Echinostomatidae); and Parorchis acanthus (Philophthalmidae). New taxa are diagnosed and H. rhigedana is redescribed.

Austrodiplostomum ostrowskiae n. sp. (Digenea: Diplostomidae: Diplostominae) from the double-crested cormorant, Phalacrocorax auritus (Phalacrocoracidae) from the Galveston, Texas area of the Gulf of Mexico, U.S.A.

Abstract Approximately 1,350 specimens of an undescribed species of Austrodiplostomum (Diplostomidae: Diplostominae) were collected from 10 double-crested cormorants, Phalacrocorax auritus (Phalacrocoracidae), from the Galveston, Texas, U.S.A., area. Austrodiplostomum compactum is synonymized with Austrodiplostomum mordax, the type species in the genus, leaving A. mordax as the only species remaining. Austrodiplostomum ostrowskiae n. sp. can be distinguished from A. mordax by having a small but distinct hindbody, shorter ceca, a uterus and vitelline fields that extend into the tribocytic organ, smaller eggs, and an anterior testis that is about the same width as the posterior testis in A. ostrowskiae n. sp. Five specimens of the neotropical cormorant, Phalacrocorax brasilianus, were also examined from the Galveston, Texas, U.S.A., area during the study, but this host species was not found to be infected with a species of Austrodiplostomum.

Revision of the genus Diclidophora Krøyer, 1838 (Monogenea: Diclidophoridae), with the proposal of Macrouridophora n. g.

The present study re-examines the detailed morphology of the type-species, Diclidophora merlangi (Kuhn, in Nordmann, 1832) Krøyer, 1838, and other Diclidophora species parasitic on gadid fishes: D. denticulata (Olsson, 1876) Price, 1943, D. esmarkii (Th. Scott, 1901) Sproston, 1946, D. luscae (van Beneden & Hesse, 1863) Price, 1943, D. minor (Olsson, 1868) Sproston, 1946, D. palmata (Leuckart, 1830) Diesing, 1850, D. phycidis (Parona & Perugia, 1889) Sproston, 1946, D. pollachii (van Beneden & Hesse, 1863) Price, 1943 and the recently described D. micromesisti Suriano & Martorelli, 1984. An amended generic diagnosis of Diclidophora Krøyer, 1838 (synonym Diclidophora Diesing, 1850) is provided, which includes the presence of a prostatic vesicle in the terminal male genitalia and the distal fusion of the median and peripheral sclerites, a1 and c1 in the clamp anterior jaw. Macrouridophora n. g. is herein proposed for species previously considered in Diclidophora, which are parasitic on macrourid and morid fishes. The clamp morphology in Macrouridophora n. g. has distinct lamellate extension attachments to peripheral sclerites c1 and the distal portion of d1, with no distal fusion between a1 and c1 in the anterior jaw. Macrouridophora macruri (Brinkmann, 1942) n. comb. is chosen as the type-species. Nine other species are herein transferred to Macrouridophora n. g.: M. coelorhynchi (Robinson, 1961) n. comb., M. lotella (Machida, 1972) n. comb., M. nezumiae (Munroe, Campbell & Zwerner, 1981) n. comb. and M. tubiformis (Rohde & Williams, 1987) n. comb. are redescribed, based on the re-examination of type or voucher specimens. Macrouridophora attenuata (Mamaev & Zubtschenko, 1979) n. comb., M. caudata (Mamaev & Zubtschenko, 1984) n. comb., M. papilio (Mamaev & Avdeev, 1981) n. comb., M. paracoelorhynchi (Mamaev & Paruchin, 1979) n. comb. and M. physiculi (Mamaev & Avdeev, 1981) n. comb. have adequately described haptoral clamps in the literature. The clamp morphology in Macrouridophora sp. from Lepidorhynchus denticulatus in Australia is also considered. Diclidophora whitsonii Suriano & Martorelli, 1984 is herein transferred to the genus Macruricotyle Mamaev & Ljadov, 1975, as M. whitsonii (Suriano & Martorelli, 1984) n. comb. D. embiotocae Hanson, 1979 is herein considered a species incertae sedis. D. caudospina Khan & Karyakarte, 1983 and D. paddiforma Deo & Karyakarte, 1979 are herein considered species inquirendae. D. aglandulosa Deo, 1977, D. glandulosa Das, 1972, D. minuta Das, 1972 and D. spindale Deo, 1977 are formally dismissed as nomina nuda. The systematic position of Diclidophora Krøyer, 1838 and Macrouridophora n. g. in the subfamily Diclidophorinae Cerfontaine, 1895 (sensu Mamaev, 1976) is discussed.

The life cycle of Haematoloechus coloradensis Cort 1915 (Digenea: Plagiorchiidae), with emphasis on host susceptibility to infection.

Mother and daughter sporocysts and xiphidiocercariae of Haematoloechus coloradensis develop in the snail, Physa virgata. Cercariae penerate and encyst in dragonfly nymphs, Tramea sp., Libellula sp., Anax sp., and in damselfly nymphs, Enallagma spp. Upon ingestion by the vertebrate host, metacercariae excyst and migrate into the lungs where they mature. Haematoloechus coloradensis is specific for its definitive host, R. pipiens, but shows some development in Ambystoma tigrinum. Although H. coloradensis is specific for its snail host, all odonate species tested served equally well as the second intermediate host.

Host-parasite relationships of Fasciola hepatica in the white mouse. IV. Studies on worm transfer and the induction of acquired immunity by worms of different ages.

Eightand 16-day-old worms were transferred to normal recipient mice via peritoneal injection, contacted the liver 72 hr after transfer, and migrated into the common bile duct when total worm age was 32 days. Eight-day-old transferred worms were present in the liver parenchyma of recipient mice for 21 to 22 days, while 16-day-old transferred worms were in the liver parenchyma for 13 to 14 days. Transferred worms (8and 16-day-old) were utilized as immunizing infections in 2 groups of normal recipient mice to control the duration of liver migration. When transferred worms had a total age of 40 days, immunized mice were given a challenge infection of 2 metacercariae per mouse. At 25 days after challenge, these mice were killed and worms were recovered. Immunization with 8and 16-day-old worms produced a significant reduction in challenge worm burden when compared to natural immunity controls. Apparently, young flukes are capable of inducing acquired immunity during the entire liver migration period. Studies on the immunology of Fasciola hepatica L. in mice have shown that male mice develop an acquired immunity against a challenge infection after a single two-worm immunizing infection (Lang, 1967; 1968a). Young worms 8 to 17 days old may be responsible for inducing functional acquired immunity in this system (Lang, 1968a). Acquired immunity in this system can be transferred to normal recipients via peritoneal exudate cells from immunized donors (Lang et al., 1967), and it is felt that the lymphocytes seen in the liver by 16 days in a first infection and in immune mice at the time of challenge are effector cells of a specific cellular immunity. As these cells respond almost immediately to the challenge worms after they enter the liver, these 8to 10-day-old worms are no doubt producing the specific antigens. No such response is seen prior to this period in the intestine or body cavity. Young worms removed from livers of normal mice 17 days after infection can be transferred to normal recipients and the worms migrate to and mature in the common bile duct; however, worms of the same Received for publication 15 June 1971. * This work was supported by NSF grant GB8713. t Present address: Department of Biology, New Mexico State University, Las Cruces, New Mexico 88001. age when removed from the livers of immune mice do not complete migration to the common bile duct in normal recipients. Apparently, as these worms were unable to establish, the immune response is against young worms during the liver migratory phase (Lang, 1968b). The present study attempts to determine the age of worm responsible for inducing acquired immunity in the mouse-Fasciola system using the technique of worm transfer. For this work on acquired immunity, a different population of Fasciola (eastern Washi gton) was used; however, it has been shown that it produces nearly the same host responses, with some differences in parasite behavior, in the strain of mouse used for this and previous work. MATERIALS AND METHODS Mice utilized were an isologous strain maintained in the Department of Parasitology, University of North Carolina. Techniques for infection and necropsy of mice, handling of recovered worms, determination of host responses, and infection of snail hosts have been described (Lang, 1966, 1970). In this study, Lymnaea bulimoides Lea was utilized as the snail host. For worm transfer, donor mice were inoculated with 15 to 22 metacercariae and necropsied 8 or 16 days later. Young worms, recovered from the livers and washed in sterile saline at 37 C, were placed in fresh saline at 13 C for 7 min stimulating them to ball up. Two worms were then injected into the body cavity of each recipient mouse using a 16-gauge needle.

A simulation model of the infection cycle of Leishmania mexicana in Neotoma micropus

Abstract A simulation model of transmission of Leishmania mexicana among Neotoma micropus by Lutzomyia anthophora was developed to predict the threshold vector density below which L. mexicana would be eliminated from a population of N. micropus within 2 years. Model results supported the hypothesis that N. micropus is a reservoir of L. mexicana . Leishmania mexicana could be maintained in a focus with an initial annual prevalence of 5.7%, which approximated the lowest non-zero prevalence found in field studies, and a peak annual vector density of only 11.4 female sand flies/woodrat. At a peak density of 2.8 female sand flies/woodrat, the prevalence declined below 1% (0.69%) at the end of 2 years. Simulations indicated that if the initial prevalence of infection was 27%, the highest annual prevalence found in the field studies, prevalence would remain > 1% (1.27%) after 2 years even if there was no sand fly activity.

Clestobothrium gibsoni n. sp. (Cestoda: Bothriocephalidae) from the bullseye grenadier Bathygadus macrops Goode & Bean (Macrouridae) in the Gulf of Mexico.

Clestobothrium gibsoni n. sp. is described from the intestine of the bullseye grenadier Bathygadus macrops (Macrouridae) collected in the northeastern Gulf of Mexico. The new species can be distinguished from both C. crassiceps (Rudolphi, 1819), the type-species of the genus, and C. neglectum (Lönnberg, 1893), the second species in the genus, by its unique ovary, which is transversely elongate and tapered on both ends rather than being U-or H-shaped, and by having more testes (60-65 vs 40-50 and 35-45 per proglottid). The new species is also compared to Bothriocephalus acheilognathi Yamaguti, 1934 and B. kivuensis Baer & Fain, 1954, two species with similar scoleces which have previously been assigned to Clestobothrium . The generic diagnosis of Clestobothrium is amended to include species with either anoperculate or operculate eggs. This is the first report of an adult tapeworm from a species of Bathygadus , and the first report of a species of Clestobothrium Lühe, 1899 (Bothriocephalidae) from the Gulf of Mexico.