The interplay of intermediate host fish and plerocercoids of diphyllobothriidean cestodes results in epizootics that are deceptively simple, but conceal complex biotic and abiotic interactions shaping each event independently. Although general descriptions of epizootics and some details of biotic interactions between enemies are known, much remains to be discovered about the abiotic and biotic forces and their interactions driving epizootics. This study shows that the duration of an epizootic of Schistocephalus solidus was sustained by high prevalence, mean intensity, and PI (parasite index—parasite∶host biomass ratio) levels among young-of-the-year and 1-yr-old threespine sticklebacks. Many infections and most parasite growth in young-of-the-year fish apparently occurred under the ice during the winter. Few new infections appear to have occurred among 1-yr-old fish, which may live 2 yr and sometimes 3 yr. The decline of the epizootic occurred as the recruitment of 1 to 2-yr-old hosts decreased significantly, followed by reduced infections of young-of-the-year fish. Thus, a major factor influencing parasite population dynamics was reduced transmission (probability of infection) as a result of overwinter host mortality among 1-yr-old fish. Mega-epizootics, named and described herein, appear to represent a “perfect storm” phenomenon dependent on a particular and rare combination of circumstances. Less extreme and more gradual epizootics may be more common and play out in myriad ways, because of complex abiotic and biotic factors influencing both parasite and host populations. The interplay of parasite and host resulting in reciprocal effects upon one another occurs during both the emergence and decline phases of an epizootic.

Although parasite habitat preference is well studied, it is rarely rigorously evaluated statistically because of many zero intensities. Attachment-site preference and intensities of 2 macroectoparasite species (Caligus elongatus and Calliobdella vivida) of Atlantic sturgeon, Acipenser oxyrinchus Mitchill, in Minas Basin, Bay of Fundy, Canada, were characterized with the use of zero-inflated negative binomial statistical models that included a fork-length offset to control for body size. Three other parasites were encountered, sometimes in high numbers on various body sites, but too few counts overall prevented construction of meaningful statistical models. Of 26 sturgeons, prevalence of (1) C. elongatus (Copepoda) was 85%, mainly on caudal fins and nonfin body sites; (2) C. vivida (Hirudinea) was 81%, mainly on the pelvic and pectoral fins, and dorsal and ventral–lateral body sites; (3) Dichelesthium oblongum (Copepoda) was 31% within the gills or burrowed into the musculature at the base of fins; (4) Argulus stizostethii (Crustacea: Branchiura) was 8%; and (5) Nitzschia sturionis (Monogenea) was 12%. Only D. oblongum was associated with visible damage, mainly as lesions on gills and soft tissues. Characterizing parasite prevalences within the Bay of Fundy is important because some parasites affect fish health and population biology.

Daubaylia potomaca is an unusual parasite for several reasons. Specifically, it has a direct life cycle in which it uses a planorbid snail, Helisoma anceps, as the definitive host. In addition, adult females have been shown to be both the infective stage and the only stage documented to be shed from a live, infected host. Finally, adults, juveniles, and eggs have been observed in all tissues and blood spaces of the host, suggesting the parasite consumes and actively migrates through host tissue. The present study examined the population and infection dynamics of D. potomaca in Mallard Lake, a 4.9-ha public access pond in the Piedmont region of North Carolina. In particular, the study examined the role of seasonality on the prevalence and mean intensity of infection of D. potomaca in the snail host. Data collected from August 2008 to October 2009 suggest that prevalence and mean intensity were inversely related in the spring and fall. Prevalence in fall 2008 was 10.3% but increased to 47.3% in spring 2009. Conversely, intensity was high in fall 2008 at 52.4 ± 8.9 worms/infected host but dropped to 3.1 ± 0.3 worms/infected host in spring 2009. During the same time, the parasites within the snails went from highly aggregated populations in the fall to a less aggregated distribution in the spring. It is hypothesized that D. potomaca induces mortality of the snail hosts during the winter, followed by a rapid recruitment event of the nematodes by the snail population after torpor.

A new tick species belonging to the African subgenus Afrixodes Morel, 1966, namely, Ixodes (Afrixodes) fynbosensis n. sp., is described. The female of I. fynbosensis is easily differentiated from the other African Ixodes species by a large, tapering triangular ventrolateral spur on palpal segment I. Nymph and larva of I. fynbosensis can be distinguished from those of other members of Afrixodes by a combination of the following characters: pointed hypostome, long auriculae, long and acute ventrolateral projections of basis capituli of nymph, only 2 pairs of central dorsal setae, and a straight posterior margin of scutum of the larva. Cytochrome oxidase I mtDNA sequence comparisons between I. fynbosensis and 10 other Ixodes Latreille, 1795, species support the recognition of this taxon as genetically distinct (>13% corrected sequence divergences separate it from the remainder of the 10 recognized species used in this study), and preliminary phylogenetic analyses reveal that this taxon is most closely related to the southern African Ixodes pilosus Koch, 1844, and Ixodes rubicundus Neumann, 1904. Ixodes fynbosensis is known only from South Africa, where females have been collected from a domestic dog and a rodent, Rhabdomys pumilio (Sparrman), and nymphs and larvae have been collected from R. pumilio and unidentified shrews belonging to the Soricidae. Sequences generated for both nymphs and adult individuals were identical, confirming the correlation between the described life stages.

The prevalence, intensity, and abundance of sea lice belonging to Lepeophtheirus or Caligus clemensi are reported from threespine stickleback (Gasterosteus aculeatus) collected from the Broughton Archipelago region of coastal British Columbia, Canada, between 2005 and 2008. In total, 25,130 sea lice were collected from 7,684 sticklebacks. The prevalence of Lepeophtheirus ranged from 51% in 2005 to 11% in 2008 and that of C. clemensi from 56% in 2007 to 24% in 2008. Chalimus stages accounted for approximately 69% of all Lepeophtheirus and 88% of Caligus specimens. Cytochrome c oxidase subunit 1 (COI) gene sequences, useful in distinguishing reference specimens belonging to 8 species of Lepeophtheirus, Caligus, and Bomolochus, were used to identify the Lepeophtheirus specimens from stickleback as L. salmonis (71%) and L. cuneifer (29%). A COI phylogenetic analysis confirmed a monophylogenetic origin of Lepeophtheirus but not of Caligus. Two genotypes were resolved in L. cuneifer, i.e., genotype A occurred twice as often as genotype B. Virtually all immature Lepeophtheirus specimens from juvenile salmon were L. salmonis. The results emphasized the need to accurately identify immature sea lice as a prerequisite to understanding sea lice ecology. The threespine stickleback may be a useful sentinel species for the abundance and diversity of the sea lice that are also parasites of wild and farmed salmon in coastal ecosystems in British Columbia.

During an investigation of the biodiversity and structure of parasite communities among native populations of the erythrinid fish Hoplias malabaricus (Characiformes) from 7 rivers in Brazil, the following monogenoidean (Dactylogyridae) species were found: Urocleidoides malabaricusi n. sp., Urocleidoides naris n. sp., Urocleidoides cuiabai n. sp., Urocleidoides brasiliensis n. sp., and Urocleidoides eremitus Kritsky, Thatcher, and Boeger, 1986. Specimens considered as a new genus of Dactylogyridae were also found. The new species are mainly distinguished from the other 14 species of Urocleidoides in the general morphology of their copulatory and anchors/bar complexes. These new species and the new dactylogyrid genus are described, as well as supplemental observations and new illustrations of U. eremitus are provided. The present findings expand the known geographical distribution of species of Urocleidoides to southeastern and midwestern Brazil. A high speciation of this genus in the tropics is hypothesized, and it is briefly discussed.

Prevalence of antibodies to Toxoplasma gondii was investigated in 673 domestic dogs from northeastern Portugal, using the modified agglutination test (MAT) with 1∶20 as cutoff for seropositivity; antibodies were found in 256 dogs (38.0%). Differences between seroprevalence levels in males (36.7%) and females (41.8%) and between pure-breed (42.1%) and mixed-breed dogs (35.2%) were not statistically significant. Multiple logistic regression analysis identified age above 12 mo (odds ratio [OR]  =  4.0), chance of eating birds or small mammals (OR  =  4.0), housing exclusively outdoors (OR  =  1.5), home-cooked meals (OR  =  3.0), and eating raw meat or viscera (OR  =  7.7) as risk factors for the canine T. gondii infection. Some control measures are suggested based on these findings.

Sarcocystis cymruensis was initially identified in skeletal muscles of 22 (11.6%) of 189 wild rats (Rattus spp.) captured in 2008 in Anning and Kunming, Peoples Republic of China. Sarcocyst walls were thin (<1 µm) and smooth. Ultrastructurally, the parasitophorous vacuolar membrane had small, osmiophilic knob-like invaginations covered with numerous vesicle-like invaginations toward the interior of the cyst. Domestic cats (Felis catus) fed sarcocysts shed sporocysts measuring 10.3 (9.8–11.0) × 7.6 (7.2–9.5) µm with a prepatent period of 6 to 8 days. Sarcocysts were infective orally to Norway rats, and oocysts and sporocysts developed in the lamina propria of the small intestine of rats fed sarcocysts. Thus, rats were both intermediate and definitive hosts for S. cymruensis.

Understanding the role of disease in population regulation is important to the conservation of wildlife. We evaluated the prevalence of Toxoplasma gondii exposure and Sarcocystis spp. infection in 46 road-killed and accidentally trapper-killed fisher (Martes pennanti) carcasses collected and stored at −20 C by the Pennsylvania Game Commission from February 2002 to October 2008. Blood samples were assayed for T. gondii antibodies using the modified agglutination test (MAT, 1∶25) and an indirect immunofluorescent antibody test (IFAT, 1∶128). For genetic analysis, DNA samples were extracted from thoracic and pelvic limb skeletal muscle from each carcass to test for Sarcocystis spp. using 18s-rRNA PCR primers. Antibodies to T. gondii were found in 100% (38 of 38) of the fishers tested by MAT and in 71% (32 of 45) of the fishers tested by IFAT. PCR analysis revealed that 83% (38 of 46) of the fishers were positive for Sarcocystis spp. Sequence analysis of 7 randomly chosen amplicons revealed the fisher sarcocysts had a 98.3% to 99.1% identity to several avian Sarcocystis spp. sequences in GenBank. Data from our study suggest that a high percentage of fishers in Pennsylvania have been exposed to T. gondii and are infected with Sarcocystis spp.

Daubaylia potomaca is a parasitic nematode that exhibits a direct life cycle using planorbid snails as their only host. Within the snail host Helisoma anceps, all developmental stages of the parasite are present at any given time. The nematode has an unusual life cycle, with the adult female being the infective stage rather than the third-stage larvae (L₃), as is commonly the case in many other parasitic nematode life cycles. In addition, length analysis showed that L₁ and L₂ were not present in tissues, suggesting that larvae hatch from eggs as the L₃. Previous studies by other investigators show that adult females abandon Biomphalaria glabrata at some point between 3 and 9 days of host death; in the present study, adult female D. potomaca leave H. anceps up to 59 days (and a mean of 14.8 days) before host death. This observation indicates a striking physiological difference between an experimental and a natural host for the parasite.

Revision of monozoic cestodes (Caryophyllidea) parasitic in commercially important walking catfish Clarias batrachus (L.) in tropical Asia (Indomalayan zoogeographical region) was carried out, based on the evaluation of newly collected material from India, Indonesia, and Thailand, as well as a study of type specimens. Instead of the 59 nominal taxa of 15 genera from 3 caryophyllidean families previously described, only 8 species of the Lytocestidae are considered to be valid: Bovienia indica (Niyogi, Gupta and Agarwal, 1982) n. comb.; Bovienia raipurensis (Satpute and Agarwal, 1980) Mackiewicz, 1994; Bovienia serialis (Bovien, 1926) Fuhrmann, 1931; Djombangia penetrans Bovien, 1926; Lucknowia microcephala (Bovien, 1926) n. comb.; Lytocestus indicus (Moghe, 1925) Woodland 1926; Pseudocaryophyllaeus ritai Gupta and Singh, 1983; and Pseudocaryophyllaeus tenuicollis (Bovien, 1926) n. comb. All valid species are redescribed and SEM photomicrographs of their scolices and photomicrographs of their eggs are provided for the first time. Crescentovitus Murhar, 1963, Heeradevina Srivastav and Khare, 2005, Pseudobatrachus Pathak and Srivastav, 2005, Pseudobilobulata Srivastav and Lohia, 2002, Pseudoclariasis Pathak, 2002, and Pseudoinverta Pathak, 2002 are invalidated and 50 nominal species are newly synonymized, including 4 species described from other fish hosts. Taxonomic status of the remaining caryophyllidean taxa reported from C. batrachus (at least 6 taxa) could not be clarified because of the unavailability of their original descriptions. A key to identification of caryophyllidean tapeworms parasitic in C. batrachus is provided. To avoid current inflation of descriptions of invalid taxa, researchers are strongly encouraged to work only with well-fixed material; damaged, decomposed, or strongly flattened specimens should not be used for taxonomic studies, and type specimens must always be deposited in internationally recognized collections.

A new species of Spauligodon, Spauligodon latasticola n. sp., from the intestines of Latastia longicaudata (Lacertidae) from Kenya is described and illustrated. Spauligodon latasticola represents the 47th species assigned to the genus and the 8th species from the Ethiopian region. The new species differs from all but 2 other species assigned to Spauligodon by the presence of a conically tapering tail in the female. The new species is separated from the 2 similar species, Spauligodon garciaprietoi and Spauligodon goldbergi, by the position of the vulva, which is anterior to the esophageal bulb in the new species, at the level of the esophageal bulb in S. goldbergi, and posterior to the esophageal bulb in S. garciaprietoi.

A new species of coccidian (Apicomplexa: Eimeriidae) is described from the feces of a western hognose snake Heterodon nasicus (Serpentes: Xenodontidae) collected from Texas, and housed in the collection of the Zoological Society of London. Oocysts of Eimeria mchenryi n. sp. are cylindrical, 35.0 ± SD 1.4 (32–37) × 17.0 ± 0.7 (16–18) µm; the shape index (length/width) is 2.05. A micropyle, oocyst residuum, and polar granule are absent. Sporocysts are subspherical 9.3 (7–11.5) × 7.7 (6–9) µm, with a shape index of 1.2. There is a sporocyst residuum, but the new species is lacking Stieda bodies. The new species is distinct from those previously named from the Xenodontidae and the allied family, Colubridae.

Two species of philometrid nematode, Philometra overstreeti and Philometroides paralichthydis, infect the southern flounder, Paralichthys lethostigma. Individuals of P. overstreeti are located between the teeth and inside the bony part of the branchial arches of the fish. Individuals of P. paralichthydis are associated with the bones of the buccal cavity and among muscles that control the dorsal and anal fins. Sequencing of part of the cytochrome oxidase I gene revealed 4 distinct genetic clades, each corresponding exactly to the 4 respective locations of the parasites in the host, suggesting the need for taxonomic revision. We hypothesized that each clade represented a separate species and, because the worms are morphologically indistinguishable, compared population level parameters of the clades comprising each currently recognized species. For each currently recognized species, the presence of worms from 1 clade was negatively correlated with the presence of worms from the other. Results also indicated significant differences between the clades in prevalences relative to both biotic and abiotic factors. Results clearly indicated major differences in the ecology of the philometrids constituting each clade. Taken as a whole, molecular and ecological data support the contention that the 4 genetic clades are likely 4 distinct species.

Contracaecum australe n. sp. is described from the Neotropic cormorant Phalacrocorax brasilianus in Chile based on morphology and the sequence analyses of multiple loci, i.e., mitochondrial cytochrome oxidase 2, mtDNA cox-2, the small subunit of the mitochondrial ribosomal RNA gene, rrnS, and the ITS-1 and ITS-2 regions of nuclear ribosomal DNA. Moreover, sequence analysis of the same genes was carried out on the morphospecies Contracaecum chubutensis Garbin et al. (2008) from Phalacrocorax atriceps. Further, genetic relationships are presented between C. australe n. sp. and C. chubutensis with respect to the related congeners from fish-eating birds previously characterized genetically on the same genetic markers, i.e., Contracaecum rudolphii A, B, C, D, and E, Contracaecum septentrionale, Contracaecum microcephalum, Contracaecum bioccai, Contracaecum pelagicum, Contracaecum micropapillatum, Contracaecum gibsoni, and Contracaecum overstreeti. Several phylogenetic analyses (MP, NJ, and BI) inferred from mitochondrial genes (cox-2, rrnS) were congruent in depicting C. australe n. sp. and C. chubutensis as forming distinct clades, highly supported, from the remainder of the Contracaecum taxa considered; thus, it validates their specific status. Further, analyses of the ITS-1 and ITS-2 sequence data of C. australe n. sp. and C. chubutensis supported their distinction with respect to the 2 sibling species, C. rudolphii D and C. rudolphii E, previously detected from Phalacrocoracidae of Australia. Morphological analysis and the differential diagnosis of male specimens of C. australe n. sp. enabled the detection of differences in a number of characters, including spicule length, peculiar shape of male tail, paracloacal papillae disposition, and shape and bifurcation depth of interlabia. According to the genetic and morphological results obtained, the erection of a new taxon from fish-eating birds of the Austral region is given and its formal description is presented. Phylogenetic trees support both C. australe n. sp. and C. chubutensis as being included in the same clade with the previously detected species from cormorants, i.e., C. rudolphii A, B, C, and C. septentrionale. The finding of C. australe n. sp. and C. chubutensis parasites of Ph. brasilianus and Ph. atriceps, respectively, appears to support a host–parasite association between the C. rudolphii A, B, and C, C. septentrionale, C. chubutensis, and C. australe n. sp. and different species of cormorants belonging to Phalacrocorax.

A myxozoan resembling species of Thelohanellus was isolated from the gills of koi (Cyprinus carpio) cultured in North Carolina. Plasmodia measuring ∼200 µm in diameter contained tear-shaped myxospores containing a single pyriform polar capsule. The spore body was concave on one side, measuring 16.2 (14.7–16.8) µm long and 5.6 (4.5–6) µm wide. The polar capsule was 6.4 (5.8–7.2) µm long and 4.2 (3.4–4.6) µm wide, containing a polar filament coiled perpendicular to the longitudinal axis of the spore body making 8 turns. Occasionally, an oblong, irregularly shaped mass of protoplasm was observed between the polar capsule and spore capsule. Analysis of 18S small-subunit ribosomal DNA sequence demonstrated this isolate as a 99.9% match with Myxobolus toyamai from gills of C. carpio. However, the case isolate lacked the characteristic second polar capsule of Myxobolus, morphologically placing it within the Thelohanellus. Here we supplement genetic sequence data with histopathology, an amended morphological description of the agent, and a review of the original classification. For future reference, we suggest this organism be referred to as Thelohanellus toyamai Kudo, 1933, in accordance with the original classification and the nomial M. toyamai be avoided because it is at best outdated and, at worst, incorrect.

In this study, we describe 2 new species of Eimeria associated with the yellow-crowned Amazon Amazona ochrocephala. Eimeria amazonae n. sp. has bilayered, ellipsoidal, and smooth oocysts that measure 48.9 × 36.2 µm; the length/width ratio is 1.35. The micropyle and oocyst residuum are both absent, but the polar granule is present. Ovoidal sporocysts are 22.2 × 11.9 µm. Stieda and sub-Stieda bodies and sporocyst residuum are present. The 2 elongate sporozoites are curved and measure 18.1 × 3.4 µm; both have 2 refractile bodies. Eimeria ochrocephalae n. sp. has bilayered, ellipsoidal, and smooth oocysts that measure 43.8 × 27.7 µm; the length/width ratio is 1.58. The micropyle and oocyst residuum are absent, but the polar granule is present; ovoidal sporocysts are 20.6 × 10.1 µm. Stieda and sub-Stieda bodies and sporocyst residuum are present; 2 elongate and curved sporozoites are 15.8 × 3.4 µm, each of which has 2 refractile bodies.

Kurilonema browni n. sp. is described on the basis of specimens found in the lungs of the scincid lizard Sphenomorphus abdictus aquilonius from Aurora Province, Luzon Island, Philippines. The new species differs from Kurilonema markovi, the only previously known species in the genus, by the presence of 2 prominent lateral pseudolabia, larger body size, shorter tail length relative to total body length, and more numerous eggs in the uteri, containing fully developed larvae. The inner surface of the buccal capsule in the new species is densely covered with rounded scales that have not been observed in K. markovi or any other rhabdiasid species. This is the first record of the genus from the Philippines.

The prevalence of Hepatozoon parasites in 460 lizards from North Africa was studied by amplification and sequencing of the 18S rRNA gene. The phylogenetic analysis of the 18S rRNA gene provides new insights into the phylogeny of these parasites with multiple genetically distinct lineages recovered. Parasite prevalence differed significantly between lacertid lizards and geckos. Our results show that there is limited host specificity and no clear relation to the geographical distribution of Hepatozoon parasites.

We genotyped pooled adult worms of Schistosoma mansoni from infected CF1, C57BL/6, BALB/c, and BALB/c interferon gamma knockout mice in order to establish if mouse strain differences selected for parasite genotypes. We also compared differentiation in eggs collected from liver and intestines to determine if there was differential distribution of parasite strains in the vertebrate host that might account for any genotype selection. We found that mouse strains with differing immune responses did not differ in resistance to infection and did not select for parasite genotypes. Schistosoma mansoni egg allele frequencies were also equally distributed in tissues and the difference between adult and egg allele frequencies was negligible.

Serum samples from 315 horses from Costa Rica, Central America, were examined for the presence of antibodies against Sarcocystis neurona, Neospora spp., and Toxoplasma gondii by using the surface antigen (SAG) SnSAG2 enzyme-linked immunosorbent assay (ELISA), the NhSAG1 ELISA, and the modified agglutination test, respectively. Anti-S. neurona antibodies were found in 42.2% of the horses by using the SnSAG2 ELISA. Anti-Neospora spp. antibodies were found in only 3.5% of the horses by using the NhSAG1 ELISA, and only 1 of these horses was confirmed seropositive by Western blot. Antibodies to T. gondii were found in 34.0% of the horses tested, which is higher than in previous reports from North and South America. The finding of anti-S. neurona antibodies in horses from geographical areas where Didelphis marsupialis has wide distribution suggests that D. marsupialis is a potential definitive host for this parasite and a source of infection for these horses.

Inoculation of northern bobwhite quail (Colinus virginianus) with low doses of Eimeria lettyae oocysts stimulates a protective immune response, suggesting immunization may be an option for controlling coccidiosis. However, the oocyst production of inoculated birds could be considerable, leading to subsequent outbreaks. To determine the oocyst production following inoculation with E. lettyae, we orally infected 12-wk-old bobwhites with 100, 1,000, or 10,000 sporulated oocysts. Fecal materials were collected on days 5–9 post-inoculation, and total oocyst production was counted in McMaster chambers. Oocyst production/bird was 49.75, 89.5, and 436 × 10⁶ for 100, 1,000, or 10,000 oocysts administered, respectively. Estimated oocysts produced/oocyst administered was 49.75, 8.95, and 4.36 × 10⁴ for 100, 1,000, or 10,000 oocysts administered, respectively. These findings not only illustrate the crowding effect of larger oocyst inocula but also illustrate the fecundity of E. lettyae at low doses. This suggests that successful immunization of bobwhites against coccidiosis with live vaccines might require attenuated strains with reduced reproductive potential.

Water buffaloes (Bubalus bubalis) are intermediate hosts for 4 species of Sarcocystis, i.e., Sarcocystis fusiformis and Sarcocystis buffalonis with cats as definitive hosts; Sarcocystis levinei with dogs as definitive hosts; and Sarcocystis dubeyi with an unknown definitive host but thought to be zoonotic. Currently, the latter species has been identified with certainty only from Vietnam. In the present study, sarcocysts of S. dubeyi are reported in 11 (30%) of 35 Egyptian water buffaloes from which the esophageal muscles were examined histologically. Sarcocysts were microscopic, measuring 180–250 × 70–110 µm in size. Ultrastructurally, the sarcocyst wall was 3.5–6.5 µm thick and had palisade-like villar protrusions which give it a striated appearance. The villar protrusions contained microtubules that were distributed along the whole villus. This is the first report of S. dubeyi from water buffaloes in Egypt.

Toxoplasmosis is an important parasitic disease worldwide and is related to certain psychiatric disorders and sterility. In the present study, serum samples from 882 female sterility patients and 107 pregnant–puerperant women were assayed for anti-T. gondii IgG antibodies using ELISA. The overall T. gondii seroprevalence was 14.8%. In the female sterility patients, 15.9% (140/882) were seropositive and, in the pregnant–puerperant women, 5.6% (6/107) were positive for anti-T. gondii IgG antibodies. There was a significant difference between the 2 groups (P < 0.05). The samples were further divided into 5 groups based on age, but no significant difference was found among the 5 groups (P > 0.05). Results of the present study argue for more attention to prevention of T. gondii infection in the female population and, in particular, women of childbearing age.

Host biodiversity can impact disease risk and influence the transmission of parasitic disease. Stream sediment–dwelling worms, Tubifex tubifex (Clitellata: Oligochaeta), are the definitive host of the parasite Myxobolus cerebralis (Myxozoa: Myxosporea), which causes whirling disease in salmonid fishes. Genetic diversity of T. tubifex is correlated with host susceptibility to M. cerebralis, and mitochondrial Lineage III is generally shown to be more likely to be infected and produce the triactinomyxon (TAM) spores than other lineages. We determined the mitochondrial lineage, relative abundance, and prevalence of infection of T. tubifex collected at 3 sites in the Madison River, Montana, where previous study had shown variation in whirling disease prevalence and severity in caged trout fry. We also compared visual identification of TAMs released from cultured worms with a molecular genetic assay (diagnostic polymerase chain reaction [PCR]) for parasite detection of both infected and uninfected worms. We estimated that mitochondrial Lineage III was most abundant at the site previously shown to have high fish disease and was also most likely to be infected. The 2 techniques for detecting parasite infection did not always agree, and the likelihood of PCR ( ) and spore (−) was not significantly different from PCR (−) and spore ( ). Differences in the relative infection prevalence for these 2 lineages may explain the wide range of infection in natural streams.

Otobius megnini has an autogenous 1 host life cycle, where larvae and nymphs stay attached inside the ear canal for long periods, but the adult tick is free living and can lay several egg batches without feeding. In order to obtain information about anatomical structures involved in this particular life cycle, nymphs and adults of O. megnini were dissected and salivary gland images were obtained in situ with the use of scanning electronic microscopy. Measurements of salivary alveoli were obtained with the use of ImageJ 1.40g software. In the nymphs, the Type I alveoli are relatively small (mean diameter: 19.6 µm) compared with those of the adults (mean: 43.4 µm) and other soft ticks in the literature. Type II alveoli in nymphs are similar (mean: 82.6 µm) to previously described alveoli in adult soft ticks. In contrast, the adults of O. megnini Type II alveoli are smaller (mean: 36.8 µm) and have a wrinkled surface. These findings provide more evidence that Type I alveoli take part in absorption of moisture during the free-living tick stages.

Hexadecylphosphocholine (miltefosine) is an anticancer drug active in vitro against various protozoan parasites, and recently used for the treatment of disseminated Acanthamoeba infection. In the present study, we present results of weak cytotoxic activity of this potential amoebicidal agent for 2 of 3 clinical isolates of Acanthamoeba spp. Although the inhibition effect for all tested concentrations was apparent, and showed 100% eradication of trophozoites of Acanthamoeba castellanii strain at a concentration of 62.5 µM after 24 hr, the strains Acanthamoeba sp. and Acanthamoeba lugdunensis exhibited low sensitivity to hexadecylphosphocholine, even in high concentrations. The determined minimal trophocidal concentrations were 250 µM for Acanthamoeba sp. and 500 µM for A. lugdunensis after 24 hr of exposure. Although hexadecylphosphocholine is a potential agent for treatment of Acanthamoeba keratitis and systemic infections, in clinical practice the possible insusceptibility of the amoebic strain should be considered for optimizing therapy.

Seroprevalence of Neospora caninum in dairy buffaloes (Bubalus bubalis) was assessed in the Lahore District of Punjab Province, Pakistan. The study revealed an overall prevalence of 54.7% for N. caninum antibodies determined through a competitive enzyme-linked immunosorbent assay performed on randomly collected serum samples. The highest prevalence was observed in buffaloes >3–5 yr of age (64.1%), followed by 57.9% for 5 to 6 yr olds, and 55.8% in 1-yr-old neonates, with high probability of infection under intensive dairy farming conditions. The pattern of prevalence was closely associated with the season as reflected by the highest prevalence (70.5%) in summer (May–August) and lowest (39.6%) in winter (November–January). Aborting buffaloes illustrated significantly higher (78.9%) exposure compared with non-aborting dams (59.8%). Prevalence in animals with canine contact was significantly higher (60.3%) than without contact (48.1%). This is the first reported prevalence of N. caninum in Pakistan.