We studied the effects of polyamines, which are necessary for proliferation and antioxidation in Trypanosoma brucei gambiense Wellcome strain (WS) and Trypanosoma brucei brucei ILtat 1.4 strain (IL). No difference was found in activity of ornithine decarboxylase (ODC), a key enzyme in polyamine synthesis in trypanosomes, in both strains maintained in vitro; higher (P < 0.05) ODC values were found in IL in vivo. However, WS in vivo exhibited higher proliferation rates with higher spermidine content and decreased host survival times than IL. The in vitro proliferation and polyamine contents of WS increased with the addition of polyamine to the l-difluoromethylornithine culture medium, but not IL. These results suggested that WS uses extracellular polyamine for proliferation. In the in vitro culture, WS was less tolerant of hydrogen peroxide (oxidative stress) than IL, and malondialdehyde levels in WS were higher than in IL. The expression of trypanothione synthetase mRNA in WS in vitro was higher than in IL. These results suggest that IL is dependent on the synthesis of polyamines for proliferation and reduction of oxidative stress, whereas WS is dependent on the uptake of extracellular polyamines. A thorough understanding of the differences in the metabolic capabilities of various trypanosomes is important for the design of more effective medical treatments.

Effects of temperature on the sporulation of the parasite Cyclospora cayetanensis were studied in 2 food substrates, dairy and basil. Unsporulated Cyclospora oocysts were subjected to freezing and heating conditions for time periods ranging from 15 min to 1 wk. Oocysts were then removed from the food substrates and placed in 2.5% potassium dichromate for 2 wk to allow viable unsporulated oocysts to differentiate and fully sporulate, and to determine the percentage sporulation as an indicator of viability. Sporulation occurred when oocysts resuspended in dairy substrates were stored within 24 hr at −15 C. When oocysts were placed in water or basil, sporulation occurred after incubation for up to 2 days at −20 C, and up to 4 days at 37 C. Few oocysts sporulated when incubated for 1 hr at 50 C. Sporulation was not observed in basil leaves or water at −70 C, 70 C, and 100 C. Sporulation was not affected when incubated at 4 C and 23 C for up to 1 wk, which was the duration of the experiment in both of the tested substrates.

Of morphologically indistinguishable small-sized neodiplostomula in the grass snake Rhabdophis tigrina in the Republic of Korea, some, such as Neodiplostomum seoulense, mature into adults in the intestines of rodents, whereas others, such as Neodiplostomum leei, migrate to rodent livers and mature in the intestines of chicks. In the present study, we aimed to observe in more detail the extraintestinal migration and development of N. leei by using various animal models, i.e., mice, rats, hamsters, rabbits, cats, and chicks. In mammals, small-sized neodiplostomula (N. leei) inoculated orally penetrated the intestinal wall, entered the peritoneal cavity, and oriented to the liver without passing through any other organ. In rodent livers, the neodiplostomula were surrounded by host inflammatory cells and fibrotic tissues from day 10 postinfection (PI); the worms were found dead by day 56 PI. When neodiplostomula from rodent livers were transferred orally to mammals, they reoriented to the liver, although they were able to develop into adults in the chick intestine by day 6–7 PI. The possibility of human infections, i.e., liver migration, by N. leei neodiplostomula, among snake consumers, warrants investigation.

The intestinal helminth communities of creek chub (Semotilus atromaculatus) were studied in the streams of southeastern Nebraska to characterize spatial variation, to determine whether drainages act as regional species pools, and to examine the spatial patterning of individual parasite species within and among drainages. Creek chub were sampled in the summer of 2003 and the spring of 2004 at each of 12 sites distributed evenly among 3 drainages in the Big Nemaha River watershed. Four intestinal helminths were recovered: Allocreadium lobatum, Proteocephalus sp., Rhabdochona canadensis, and Paulisentis missouriensis. Host size had little or no effect on the composition of the parasite communities of creek chub, either among individual fish or among samples. In contrast, drainage and sample date explained 82% of the variation in mean infracommunity species richness among samples, and 62% of the variation in mean infracommunity abundance among samples. Drainage differences were determined by the distributions of P. missouriensis and R. canadensis; whereas, A. lobatum and Proteocephalus sp. were more uniformly distributed among drainages. Each drainage was characterized by a unique pattern of species diversity at infracommunity, component community, and drainage levels of organization.

The cercaria morphology of Echinochasmus japonicus was investigated using light and scanning electron microscopy. Cercariae, liberated from naturally infected snails (Parafossarulus manchouricus), had ovoid bodies and diminutive tails. The cercaria tegument was covered with minute spines. Four type II sensory papillae were observed on the dorsal side of the oral sucker, and type I papillae were distributed on the dorsal tegument surfaces. When cercariae were kept in the same bath as the freshwater fish, Pseudorasbora parva, which were free from trematode infections, parasites encysted only in the gills of fishes at day 4 postinfection (PI). The outermost metacercaria wall was fully formed in host tissues at day 7 PI. Adult worms were recovered from the intestines of rats, chicks, and ducks 28 days after experimental exposure to metacercariae. The head crown of the adult was armed with 24 collar spines, which were interrupted dorsal to the oral sucker, and the species was identified as E. japonicus.

We studied age-dependent patterns of flea infestation in 7 species of rodents from Slovakia (Apodemus agrarius, A. flavicollis, A. sylvaticus, A. uralensis, Clethrionomys glareolus, Microtus arvalis, and M. subterraneus). We estimated the age of the host from its body mass and expected the host age-dependent pattern of flea abundance, the level of aggregation, and prevalence to be in agreement with theoretical predictions. We expected that the mean abundance and the level of aggregation of fleas would be lowest in hosts of smallest and largest size classes and highest in hosts of medium size classes, whereas pattern of variation of prevalence with host age would be either convex or asymptotic. In general, mean abundance and species richness of fleas increased with an increase in host age, although the pressure of flea parasitism in terms of number of fleas per unit host body surface decreased with host age. We found 2 clear patterns of the change in flea aggregation and prevalence with host age. The first pattern demonstrated a peak of flea aggregation and a trough of flea prevalence in animals of middle age classes (Apodemus species and C. glareolus). The second pattern was an increase of both flea aggregation and flea prevalence with host age (both Microtus species). Consequently, we did not find unequivocal evidence for the main role of either parasite-induced host mortality or acquired resistance in host age-dependent pattern of flea parasitism. Our results suggest that this pattern can be generated by various processes and is strongly affected by natural history parameters of a host species such as dispersal pattern, spatial distribution, and structure of shelters.

Infrapopulations of trematode metacercariae were monitored in the snail Lymnaea stagnalis over 17 yr (1982–1999) at Chany Lake, Novosibirskaya Oblast', Russia. Eighteen trematode species were recorded. Patterns of occurrence varied from 4 species (Echinoparyphium aconiatum, Echinoparyphium recurvatum, Moliniella anceps, and Cotylurus cornutus) that persisted at relatively high prevalence (>60% of samples) across sites, seasons, and years, to species that were very rare and sporadic in occurrence. The stability of the 4 common species was probably because of their occurrence either in a wide range of definitive hosts or in a host adapted to the extreme abiotic changes that occurred from year to year in these wetlands. The prevalence and mean abundance of C. cornutus were negatively correlated with water level in the wetlands; its prevalence was also correlated with water temperature. The mean abundance of M. anceps was positively correlated with water level. The most probable explanation for the cyclic dynamics of infections of the common species is change in population sizes and densities of definitive and intermediate hosts, which mediated cyclic alterations in water levels.

Host–parasite association among 58 flea species parasitizing 40 mammal species in the Great Basin Desert of the western United States was investigated. Increased flea species richness was correlated with larger geographic ranges and stable locomotion of hosts. Hosts from habitats of moderately low productivity (sage and grass) and of Peromyscus maniculatus size, 10–33 g, had the highest flea species richness. Larger hosts had fewer flea species, but fleas were more prevalent. Increased host species richness correlated with flea species eye size. Mammals clustered into 3 major and 1 minor ecological groups, and fleas clustered into 2 major groups among rodents, and 6 minor groups, forming 12 host–parasite biocenoses. Factors producing biocenoses were shared burrows of mice and rats; food chains of hares, rabbits, squirrels, and their predators; keystone mammals: Lagurus curtatus, Neotoma lepida, Ochotona princeps, and Spermophilus townsendii; keystone fleas: Megabothris abantis, and Meringis hubbardi; or host isolation, Neotoma cinerea with Oropsylla montana, Sorex vagrans with Corrodopsylla curvata, and Tadarida brasiliensis with Sternopsylla distincta. Although host relatedness accounted for flea prevalence, host sociality explained the presence or absence of mammal–flea relationships.

The common brushtail possum (Trichosurus vulpecula) has well adapted to increasing urbanization, resulting in greater interaction with humans and their domestic pets. Wildlife species in urban areas face a higher risk of exposure to zoonotic pathogens and may be affected by parasites hosted by cats (Toxoplasma gondii) or dogs (Neospora caninum), yet it is unknown to what extent urban T. vulpecula are exposed to these parasites. Antibodies to T. gondii and N. caninum were assayed in sera of 142 adult possums from the city of Sydney, Australia. Using the modified agglutination test, antibodies to T. gondii were found in 9 (6.3%) of the 142 animals in titers of 1:25 (4), 1:50 (1), 1:100 (1), 1:800 (1), 1:3,200 (1), 1:6,400 (1), and 1:12,800 (1). Of some T. vulpecula multiple sera samples within a 2-yr frame could be collected, but seropositive animals in general were not recaptured after initial seroconversion. One possum had a high T. gondii titer on 2 consecutive bleedings, 14 mo apart, and seropositive possums appeared normal when captured. Sex seemed not to have an affect on antibody prevalence, but age and location may play a role. Antibodies to N. caninum were not detected in 1:25 dilution of sera in the N. caninum agglutination test, indicating that T. vulpecula may not have been exposed to this parasite. This is the first serological survey for T. gondii and N. caninum infections in urban T. vulpecula.

Taeniid cestodes infect humans and livestock, causing considerable morbidity and mortality, as well as economic loss. Substantial progress has been made toward the production of recombinant vaccines against cysticercosis in livestock animals. Further development of these vaccines would be aided if a reliable in vitro test were available to measure host-protective immune responses in vaccinated animals. Here, we describe in vitro oncosphere-killing assays for the quantification of host-protective serum antibodies against Taenia pisiformis, Taenia ovis, Taenia saginata, and Taenia solium in rabbits, sheep, cattle, and pigs, respectively. Activated oncospheres of T. pisiformis, T. ovis, T. saginata, and T. solium were incubated in vitro in culture medium, test serum, and a source of complement, and oncosphere killing was assessed after 10 days of culture. In vitro oncosphere killing reflected the presence of specific antibody, and the oncosphere-killing assay typically indicated immunity to the homologous parasite that had been determined in vivo. This study describes the first reliable oncosphere-killing assays for T. pisiformis, T. ovis, T. saginata, and T. solium. These assays will be used for further research into the optimization of recombinant vaccines against cysticercosis.

The parasite fauna of Dissostichus eleginoides was examined from locations around the Falkland Islands. In total, of 11,362 individual parasites of 27 taxa were recovered from 105 fish. Two species, Ceratomyxa dissostichi and Sphaerospora dissostichi, represent new host records. The nematode Ascarophis nototheniae and the larval acanothocephalan Corynosoma bullosum were found to be new locality records and add to the knowledge of the biogeography and host specificity of parasites on the Patagonian Shelf. There were no significant differences in the mean abundance and prevalence of parasites recovered between sexes. Therefore, sex was not considered in further analysis and the data were pooled. Cysts of unknown etiology (CUE), the monogenean Neopavlovskioides georgianus, the larval acanthocephalan Corynosoma bullosum, and the digenean Neolepidapedon magnatestis had significant positive correlations with increasing host length. The larval Trypanorhynch cestode Grillotia erinaceus and the digenean Elytrophalloides oatesi showed significant negative correlations with increasing host length. CUEs, N. georgianus, the digenean Gonocerca physidis and E. oatesi showed statistically significant prevalence between summer, winter, and spring. The effect of depth on parasite communities was also examined, initially using a linear discriminant function analysis. The prevalence of individual parasites was then compared between depth strata using the chi-square test. The parasite communities on the shelf and deep water (>1,000 m) were found to be different, whereas those caught at intermediate depths on the shelf slope were found to have parasite communities that were intermediate, containing a mixture of shelf and deeper-water parasites. The causes of the variations in parasite faunas in association with these intrinsic and extrinsic factors are discussed.

The precise transmission mode(s) of acephaline gregarines in their earthworm hosts has long been questioned, yet a rigorous experimental evaluation of sexual transmission is currently lacking. That Monocystis sp., a common gregarine parasite of the earthworm Lumbricus terrestris, infects the sexual organs of its host is suggestive of sexual transmission. Considering the divergent evolutionary consequences of various modes of transmission, excluding or proving sexual transmission in this host– parasite system is critical to fully understanding it. We cultured uninfected earthworms from cocoons and subsequently mated them to either an infected or uninfected partner (from the wild). We then compared these individuals with an orally infected group, which were infected using a newly developed gavage (oral injection) method. Our data have unambiguously established that (1) horizontal sexual transmission does not play a significant role in the transmission of Monocystis sp., and (2) oral transmission through the soil is likely the principal mode of transmission between earthworms. This finding is important to models of mate-choice because infection avoidance does not appear to drive mating decisions. Finally, we further report a successful and relatively simple method to obtain infection-free individuals, which can subsequently be infected via oral gavage and used in empirical studies.

Parelaphostrongylus odocoilei is a protostrongylid parasite that has recently been recognized at several locations in sub-Arctic, but not Arctic, North America. We investigated factors that may determine the distribution of P. odocoilei, including suitable gastropod intermediate hosts, temperature requirements for larval development in gastropods, and larval emergence facilitating overwinter transmission. We collected and experimentally infected gastropods from a site in the sub-Arctic where P. odocoilei is at the northern limit of its distribution. Deroceras laeve, Catinella sp., and Euconulus cf fulvus, but not members of the Pupillidae, were suitable intermediate hosts. We describe bionomics of larvae of P. odocoilei in D. laeve and Catinella sp. Infective larvae emerged from all slugs (D. laeve) and 60% of Catinella sp. snails, and emergence from D. laeve was intensity dependent. Emerged infective larvae survived up to 6 mo under conditions approximating that of the subnivean environment. In D. laeve, there was a direct relationship between temperature and development rate of larvae of P. odocoilei. Larvae of P. odocoilei did not develop to infective stage below the theoretical threshold (8.5 C), and required a minimum of 163 degree days to complete development. These developmental parameters can be incorporated into a model to predict larval development in the field. Knowledge of the factors influencing larval bionomics provides the foundation for predicting temporal and spatial patterns of parasite distribution, abundance, and transmission.

Susceptibility of free-living infective stages of parasites to contaminants is relatively understudied compared with independent effects on measures of host health or immunity, but may be important in affecting prevalence and intensity of parasite infections. We investigated whether atrazine, an herbicide commonly used in North America, affected the cercariae of 4 different species of digenetic trematodes, and found that effects of atrazine concentration on mortality and activity of cercariae varied among species. Mortality of Echinostoma trivolvis increased in a 200 μg/L atrazine solution, and a species of Alaria showed both decreased activity and increased mortality. We also examined whether the ability of E. trivolvis to infect the second intermediate host, larval amphibians, was compromised by atrazine exposure. Longevity and prevalence of E. trivolvis cercariae was affected at 200 μg/L atrazine, whereas intensity of infection in Rana clamitans tadpoles was reduced at both 20 μg/L and 200 μg/L atrazine. Our results indicate that the viability of cercariae of some species is compromised by exposure to atrazine, emphasizing the importance of considering the influence of contaminants on free-living stages of parasites in addressing how environmental degradation may relate to host parasitism.

We collected 1,023 lice, representing 5 species, from rats and domestic cattle throughout 13 governorates in Egypt and tested these lice for Anaplasma marginale, Bartonella spp., Brucella spp., Borrelia recurrentis, Coxiella burnetii, Francisella tularensis, and Rickettsia spp. by PCR amplification and sequencing. Five different louse-borne bacterial agents were detected in lice from rodents or cattle, including “Bartonella rattimassiliensis”, “B. phoceensis”, and Bartonella sp. near Bartonella tribocorum, Coxiella burnetii, and Rickettsia typhi. More lice from governorates bordering the Mediterranean and Red Seas contained pathogens. Our data indicate that lice of urban and domestic animals harbor pathogenic or potentially pathogenic bacterial agents throughout Egypt.

This work reviews the significant community of digenean trematodes observed infecting the edible cockle, Cerastoderma edule, and the snail Nassarius reticulatus in the channel of S. Jacinto, Ria de Aveiro Estuary, Portugal. The Digenea observed comprise 15 species, belonging to the families Bucephallidae (1), Echinostomatidae (4), Gymnophallidae (3), Lepocreadiidae (1), Microphallidae (1), Monorchiidae (1), Renicolidae (1), Strigeidae, (1), and Zoogonidae (2). The species were studied by light microscopy and scanning electron microscopy. Information is included for hosts, sites of infection, prevalence, and a brief description of parasite surface morphology. The significance of these observations is compared with the presence of these digeneans from other regions, mainly the Atlantic Ocean and Mediterranean Sea. The Ria de Aveiro is a geographical location conducive to extensive species co-occurrence resulting from the overlap between southern (Mediterranean) and northern definitive hosts of the parasites. Differences in life cycle strategies were observed and discussed.

A Babesia sp. isolated from eastern cottontail rabbits (Sylvilagus floridanus) is morphologically similar and genetically identical, based on SSU rRNA gene comparisons, to 2 agents responsible for human babesiosis in the United States. This zoonotic agent is closely related to the European parasite, Babesia divergens. The 2 organisms were characterized by in vitro comparisons. In vitro growth of the rabbit Babesia sp. was supported in human and cottontail rabbit erythrocytes, but not in bovine cells. Babesia divergens was supported in vitro in bovine and human erythrocytes, but not in cottontail rabbit cells. Morphometric analysis classifies B. divergens as a small babesia in bovine erythrocytes, but the parasite exceeds this size in human erythrocytes. The rabbit Babesia sp. is large, the same size in both human or rabbit erythrocytes, and is significantly larger than B. divergens. Eight or more rabbit Babesia sp. parasites may occur within a single erythrocyte, sometimes in a floret array, unlike B. divergens. The erythrocyte specificity and morphological differences reported in this study agree with previous in vivo results and validate the use of in vitro methods for characterization of Babesia species.

A new nematode species Dichelyne (Cucullanellus) mariajuliae n. sp., is described based on specimens collected from the black drum, Pogonias cromis (Linnaeus, 1766), from Mar Chiquita coastal lagoon, Buenos Aires Province, Argentina (37°32′S, 57°19′W) (prevalence 75%, mean intensity 3.75). Among Dichelyne (Cucullanellus), the new species is unique in having the papillae 2 situated at the level of ventral sucker in males and bearing subcuticular ornamentation in the female tail.

Maracaya africana n. sp. (Nematoda: Cosmocercidae) from the large intestine of the lizard Chamaeleo inturensis collected in Democratic Republic of Congo is described and illustrated. This is the first record of a species of Maracaya Diaz-Ungria (1963) for Africa. Light microscopy and scanning electron microscopy (SEM) studies revealed morphological differences in the structure of the male caudal end and cephalic end, which enabled us to differentiate these new species from the others. A key for determination of all species in the genus is provided.

Oswaldocruzia nicaraguensis n. sp. (Strongylida: Molineidae) from the intestines of Ameiva festiva (Sauria: Teiidae) is described and illustrated. Oswaldocruzia nicaraguensis represents the 78th species assigned to the genus and is most similar to the Caribbean species of the genus by possessing spicules in which each of the 3 divisions terminates in numerous fine points. Of the 8 species assigned to this group, O. nicaraguensis is most similar to Oswaldocruzia moraveci; of the 8 species, only O. moraveci and O. nicaraguensis possess a type II bursa and lack cervical alae. It is separated from O. moraveci by the position of the tips of ribs 5–6; close together in O. nicaraguensis, well separated in O. moraveci.

Anuracanthorhynchus tritaxisentis n. gen., n. sp. from the intestines of the Brazilian frog Hylodes phyllodes (Leptodactylidae) is described and illustrated. Anuracanthorhynchus tritaxisentis n. gen., n. sp., is unique among the echinorhynchid Acanthocephala by possessing a spherical proboscis supporting a small number of hooks of equal size. It is the sixth acanthocephalan species reported from South American anurans.

In February 2004, a mass die-off of common goldfish Carassius auratus L., presumptively caused by bacterial coldwater disease (Flavobacterium psychrophilum), occurred at Fern Ridge Reservoir, Oregon. A range of size classes was affected, but all mature fish were female and all fish were infected with a single myxozoan, Chloromyxum auratum n. sp. No histological changes were observed associated with the parasite. Infection was represented by mictosporic plasmodia and free-floating spores in the gall bladder. Parasite spores were nearly spherical, 13.6 μm long × 12.6 μm wide × 13.1 μm thick, and possessed 4 equal-sized polar capsules. Spores had a coglike appearance in apical view because of distinct ridges 2.1 μm high protruding from the valve cells. There were 6–9 extrasutural ridges per valve (15–20 ridges per spore), aligned along the longitudinal axis, with some branching, and convergence at both poles. Morphologically, spores identified most closely with Chloromyxum cristatum Léger, 1906; however, 18S rDNA sequence data indicated only 97.5% similarity over 2,076 bp with Chloromyxum cyprini, the only synonym of C. cristatum for which DNA data are available; additional sequence data may reveal the other synonyms to be distinct species. This is the first record of a species of Chloromyxum from goldfish.

Three new Rhinebothrium Linton, 1890 species, R. kinabatanganensis n. sp., R. megacanthophallus n. sp., and R. abaiensis n. sp., collected from the spiral intestines of 6 freshwater whiprays (Himantura chaophraya, Dasyatidae) in the Kinabatangan River, Malaysian Borneo, are described. This is the first record of cestodes from the Kinabatangan River and from H. chaophraya. The new Rhinebothrium species are differentiated from the 34 valid Rhinebothrium species in addition to 2 species, Echeneibothrium hui Tseng, 1933 and E. oligotesticularis Subramaniam, 1940 that are herein transferred to Rhinebothrium. Each of the new species was examined with light and scanning electron microscopy. Two of the new species possess cilia on their bothridia, which have not previously been reported for members of this genus.

Species of Leucocytozoon (Haemosporida, Leucocytozoidae) traditionally have been described based on morphological characters of their blood stages and host cells, with limited information on their avian host specificity. Based on the current taxonomy, Leucocytozoon toddi is the sole valid species of leucocytozoids parasitizing falconiform birds. Using a nested polymerase chain reaction protocol, we determined the prevalence of Leucocytozoon infection in 5 species of diurnal raptors from California. Of 591 birds tested, 177 (29.9%) were infected with Leucocytozoon toddi. Subsequent phylogenetic analysis of the cytochrome b gene revealed that distinct haplotypes are present in hawks of these genera. Haplotypes present in Buteo spp. are not found in Accipiter spp., and there is a 10.9% sequence divergence between the 2 lineage clades. In addition, Leucocytozoon sp. from Accipiter spp. from Europe group more closely with parasites found in Accipiter spp. from California than the same California Accipiter species do with their sympatric Buteo spp. Similarly, a Leucocytozoon haplotype from a Common Buzzard (Buteo buteo) from Kazakhstan forms a monophyletic lineage with a parasite from B. jamaicensis from California. These results suggest that Leucocytozoon toddi is most likely a group of cryptic species, with 1 species infecting Buteo spp. and 1 or more species, or subspecies, infecting Accipiter spp.

The first description of the male and a redescription of the female of the nematode Philometra clavaeceps Dogiel and Akhmerov, 1959, a parasite of east Asian cyprinids, are presented on the basis of specimens collected from Culter erythropterus Basilewsky and Culter dabryi Bleeker from Liangzi Lake (the Yangtze River basin), Hubei Province, central China. Gravid females from the fish abdominal cavity, penetrating often into ovaries, occurred in May–June, whereas conspecific males and young mature females on the swimbladder were recorded in January. Philometra clavaeceps seems to have a pronounced annual maturation cycle in the locality. The finding of P. clavaeceps in C. dabryi represents a new host record.

The renal parasite Eimeria auritusi has caused several mortality events in double-crested cormorants (DCC; Phalacrocorax auritus) in the Midwest and southeastern United States. This parasite has only been detected during large-scale outbreaks, and its presence and prevalence in healthy populations of cormorants is unknown. In this study, 80 DCC were collected from the Chattahoochee River near Fort Gaines, Georgia, and examined for kidney and intestinal coccidia. Eighteen (22.5%) and 56 (70%) of the DCC were positive for E. auritusi and a new species of intestinal Eimeria, respectively. Oocysts of the new intestinal Eimeria species had a thin colorless wall, were ovoid with rare bumps on the outer surface, and measured 17.1 μm ± 1.5 × 14.7 μm ± 1.0 (16–18.5 × 13–17), with an average length:width ratio of 1.17 μm (1.03–1.29). A prominent micropyle (4–4.5 μm) was present, and a large oval-to-round polar body (2.5 μm) was located beneath the micropyle. Sporocysts were ovoid and measured 9.6 μm ± 0.6 × 5.9 μm ± 0.5 (8.5–10.5 × 5–6.5), with an average length:width ratio of 1.63 (1.3–1.82) with small stieda body present. Amplification and sequencing of a fragment of the 18S rRNA gene indicated that the 2 DCC Eimeria species and 2 Eimeria species from cranes were in a separate group from other Eimeriidae. These data indicate that E. auritusi and this new species of intestinal Eimeria are prevalent in this apparently healthy DCC population. The cause of renal coccidiosis outbreaks in other populations of cormorants is unknown but could be due to crowding or stress during the winter months or some other associated pathogen or immunosuppressor that might predispose individuals to clinical disease.

We demonstrate here that dipalmitoylphosphatidylcholine (DPPC) liposome has an antitrypanosomal effect, especially against the bloodstream forms (BSFs) of African trypanosomes (Trypanosoma congolense, T. brucei rhodesiense, and T. brucei brucei). The DPPC liposome significantly decreased the in vitro percentage of viable and motile BSF African trypanosomes but only marginally reduced the percentage of viable and motile procyclic form (PCF) of trypanosomes. The DPPC liposome absorption was much more pronounced to BSF than to PCF trypanosomes. Administration of the DPPC liposome showed a slight but significant reduction in the early development of parasitemia in T. congolense–infected mice. These results suggest that parasites were killed by specific binding of the DPPC liposome to the trypanosomes. This work demonstrates for the first time that a liposome has antitrypanosomal activity.

Antibodies to Toxoplasma gondii were determined by indirect enzyme-linked immunosorbent assay in serum samples from domestic rabbits from 3 rabbit farms in Mexico. Antibodies to T. gondii were found in 77 (26.9%) of 286 animals. On the farm with the higher rearing standards, the seroprevalence was 18.7%, whereas on the farm with medium standards and another managed by a family, seroprevalence was 39.7 and 33.3%, respectively. This report is the first report concerning the prevalence of antibodies to T. gondii in rabbits from Mexico. Although the prevalence found in the present study is within the range reported for other countries, 2 of the farms revealed a relatively high prevalence, which was probably associated with the presence of cats inside rabbit houses.

A nondestructive protocol for preparing specimens of Monogenoidea for both α-taxonomic studies and reconstruction of 3-dimensional structure is presented. Gomori's trichrome, a stain commonly used to prepare whole-mount specimens of monogenoids for taxonomic purposes, is used to provide fluorescence of genital spines, the copulatory organ, accessory piece, squamodisc, anchors, hooks, bars, and clamps under laser scanning confocal microscopy.

The successful propagation of Cryptosporidium parvum in cell-free culture medium was recently reported. To investigate whether this phenomenon could be broadened to include other C. parvum isolates, as well as Cryptosporidium hominis, we attempted to propagate 3 isolates in cell-free medium under reported culture conditions. Cryptosporidium oocysts from C. parvum strains Moredun (MD) or IOWA or C. hominis strain TU502 were added to media containing coagulated newborn calf serum. The cultures were sampled at various times throughout a 45 (IOWA) or 78 (MD, TU502)-day period and were microscopically examined for various life stages of Cryptosporidium. Cell-free cultures harvested on days 45 and 68 postinoculation were tested for in vitro infectivity on Madrin-Darby bovine kidney cells. In vivo infectivity testing was performed using either infant or 2-wk-old immunosuppressed C57BL mice with cell-free cultures harvested on days 52 and 78. Fecal and gut samples collected from mice were examined by modified acid-fast staining. Data from wet mounts, electron microscopy, and in vitro and in vivo infectivity testing showed that the original oocysts did not complete their life cycle and produce new, viable, infectious oocysts in cell-free culture. Thus, we conclude that this is not a universal phenomenon or readily accomplished.

A simple and single-step technique based on multiplex PCR (multiplex polymerase chain reaction) has been developed for simultaneous identification of Brazilian Biomphalaria species, the intermediate hosts of Schistosoma mansoni, and their diagnosis of infection by the trematode. We used species-specific primers directed both to the internal transcribed spacer 2 (ITS2) of ribosomal DNA from 3 of the S. mansoni host species and to the mitochondrial DNA (mtDNA) from the trematode. Those primers were used simultaneously in a single multiplex-PCR reaction, and template DNA was obtained from S. mansoni– infected and noninfected snails. The results were visualized in silver stained polyacrylamide gels, revealing the presence of specific bands. The methodology has shown to be efficient, fast, and reproducible for Biomphalaria species identification and diagnosis of snails infected by S. mansoni during prepatent periods.

A technique was developed for immunolabeling Cryptosporidium parvum oocysts for subsequent observation by transmission electron microscopy. This method was developed to maintain architectural integrity of the oocyst wall and improve fixation of internal contents. The improved fixation and embedding method permits efficient immunolabeling of both nonexcysted and excysted C. parvum oocysts and may be applicable to other oocyst- and cyst-forming protozoa.

Parastrongylus (=Angiostrongylus) costaricensis was first reported in the United States from cotton rats, Sigmodon hispidus, in Texas in 1979. Here, we report the findings of P. costaricensis in a siamang (Hylobates syndactylus) from the Miami MetroZoo, in 2 Ma's night monkeys (Aotus nancymaae) from the DuMond Conservancy located at Monkey Jungle in Miami, in 4 raccoons (Procyon lotor) trapped near the MetroZoo, and in an opossum (Didelphis virginiana) trapped at the MetroZoo. These records are the first records of P. costaricensis from all 4 species of hosts. All of the primates were zoo-born, and the raccoons and opossum were native, indicating that this parasite is now endemic at these 2 sites.

One hundred extended growth walleye fingerlings, Sander vitreus (Percidae), collected on 6 October 2004, from 1 rearing pond at the Lake Mills State Fish Hatchery in Lake Mills, Wisconsin, were examined for parasites. Diplostomum sp. (Trematoda: Diplostomatidae), Contracaecum sp. (Nematoda: Anisakidae), Bothriocephalus cuspidatus (Cestoda: Bothriocephalidae), and Proteocephalus sp. (Cestoda: Proteocephalidae) were the only parasites found. The first 3 species occurred as larval stages. Diplostomum sp. and Contracaecum sp. had similar prevalences, mean intensities, and mean abundances (72%, 2.2, and 1.6 and 71%, 2.1, 1.5, respectively) in walleye fingerlings. A headlamp technique used by the Wisconsin Department of Natural Resources personnel generated a prevalence of Diplostomum sp. in the lens that overestimated the prevalence of Diplostomum sp. found in a random subsample of 100 fingerlings examined with a microscope. Proteocephalus sp. and B. cuspidatus infected 14 and 12 fingerlings, respectively.

Paracreptotrematina limi Amin and Myer, 1982 (Trematoda), an intestinal fluke specific to the mudminnow, Umbra limi, is conventionally classified within the papillose Allocreadiidae. Its unusual morphology (lack of identifiable vitellaria, large fully embryonated terminal eggs), assumptions of homology of its 2 atypical muscular oral ‘papillae’ (lobes) with those of the Bunoderinae, and its unknown life cycle make this classification tenuous. Previous phylogenetic analyses of the papillose allocreadiids, based on morphology, placed P. limi as a basal papillose allocreadiid. We tested this hypothesis with a phylogenetic analysis by using partial sequences of the 28S ribosomal RNA gene and the cytochrome c oxidase subunit I gene from several plagiorchiiform taxa, including reportedly related allocreadiids as well as selected species of Plagiorchiidae, Haematoloechidae, and Macroderoididae. Results of phylogenetic analyses of the 28S rRNA gene fragments by using parsimony criteria support the classification of P. limi as an allocreadiid and place it as a sister taxon to a clade with Allocreadium lobatum Wallin, 1909, Bunodera luciopercae (Müller, 1876) and Crepidostomum cooperi Hopkins, 1931, with Polylekithum ictaluri (Pearse, 1924) basal to all of them. Analysis of the cytochrome c oxidase subunit I gene sequence data from fewer taxa supports the placement of P. limi relative to 3 (A. lobatum, C. cooperi, and P. ictaluri) of the 4 allocreadiid taxa. These results also suggest that the previous conception of the papillose allocreadiids as a monophyletic assemblage that includes P. limi may require a reappraisal.

Two species of sandflies (Lutzomyia) are competent vectors of Plasmodium mexicanum, a malaria parasite of lizards. The very patchy distribution of sites with high P. mexicanum prevalence in the lizards, and often low or even nil sandfly density at such sites, provoked an evaluation of 2 common lizard ectoparasites, the tick Ixodes pacificus and the mite Geckobiella occidentalis, as potential passive vectors. Plasmodium sp.-specific polymerase chain primers were used to amplify a long segment of the mitochondrial cytochrome b gene that is unlikely to survive intact if the parasite cells are killed within a blood-feeding arthropod. The segment was strongly amplified from sandflies (the positive control for the method) from 1 to 96 hr postfeeding on an infected lizard. For ticks, the gene fragment was poorly amplified at 0 hr postfeed, and not amplified after 2 hr. In contrast, strong amplification of the parasite DNA was observed from mites from 0 to 20 hr postfeed, and weak amplification even at 96 hr.

The radioresistance of Anisakis simplex third-stage larvae and the possible role of sublethal radiation on superoxide dismutase (SOD) were investigated. Larvae were isolated from the viscera of the sea eel Anago anago; irradiated with 10, 100, 200, 500, or 1,000 Gy; and then given orally to rats. Worms were recovered at 16 hr postinoculation. Most larvae were found to have invaded the gastric wall, omentum, and abdominal cavity, suggesting that their viability and infectivity were not controlled by irradiation with the doses used. To determine the relationship between SOD activities in parasites and their radiosensitivities, the larvae of A. simplex and the metacercariae of Neodiplostomum seoulense (a radiosensitive control) were irradiated with 0, 30, 100, or 500 Gy, and parasite SOD levels were measured. In nonirradiated A. simplex larvae, the average SOD level was 38.9 U/mg, and this increased to 51.3 U/mg at 500 Gy. However, at all radiation doses applied, SOD activities of N. seoulense metacercariae were significantly (P < 0.05) lower than those of A. simplex larvae. Our results demonstrate that A. simplex third-stage larvae are radioresistant, and suggest that SOD plays a role in this radioresistance.

Numerous polymerase chain reaction (PCR)-based methods have been developed and used increasingly to screen vertebrate blood samples for the diagnosis of haemosporidian blood parasites (Sporozoa, Haemosporida), but a rigorous evaluation of the sensitivity of these methods for detecting mixed infections of different haemosporidian species belonging to the same and different genera and subgenera is lacking. This study links the information obtained by nested cytochrome b PCR and traditional microscopy in determining mixed haemosporidian infections in naturally infected birds. Samples from 83 individual passerine birds with single infections of Haemoproteus or Plasmodium spp., as determined by mitochondrial DNA amplification, also were investigated by microscopic examination of stained blood films. Thirty-six samples (43%) were found to harbor mixed Haemoproteus, or Plasmodium spp. infections, or both. Thus, the PCR assays alone underestimate the occurrence of mixed infections of haemosporidian parasites in naturally infected birds. To determine the true species composition of the haemosporidians in each individual host, PCR diagnostics need to be improved. Specific primers for Haemoproteus spp. and Plasmodium spp. should be developed. Ideally, a combination of the approaches of both microscopy and PCR-based methods is recommended for this purpose.

The phylogenetic relationship of avian Babesia with other piroplasms remains unclear, mainly because of a lack of objective criteria such as molecular phylogenetics. In this study, our objective was to sequence the entire 18S, ITS-1, 5.8S, and ITS-2 regions of the rRNA gene and partial ß-tubulin gene of B. poelea, first described from brown boobies (Sula leucogaster) from the central Pacific, and compare them to those of other piroplasms. Phylogenetic analyses of the entire 18S rRNA gene sequence revealed that B. poelea belonged to the clade of piroplasms previously detected in humans, domestic dogs, and wild ungulates in the western United States. The entire ITS-1, 5.8S, ITS-2, and partial ß-tubulin gene sequence shared conserved regions with previously described Babesia and Theileria species. The intron of the ß-tubulin gene was 45 bp. This is the first molecular characterization of an avian piroplasm.

The crisis of emerging infectious disease stems from the absence of comprehensive taxonomic inventories of the world's parasites, which includes the world's pathogens. Recent technological developments raise hopes that the global inventory of species, including potential pathogens, can be accomplished in a timely and cost-effective manner. The phylogenetics revolution initiated by systematists provides a means by which information about pathogen transmission dynamics can be placed in a predictive framework. Increasingly, that information is widely available in digital form on the internet. Systematic biology is well positioned to play a crucial role in efforts to be proactive in the arena of emerging parasitic and infectious diseases.