Probopyrus pandalicola is a bopyrid isopod that infects several palaemonid shrimp species, including the daggerblade grass shrimp Palaemonetes pugio. The parasite can have several negative effects on its host, including loss of hemolymph, reduced reproductive potential, and decreased molting frequency and growth. To date, there are conflicting reports on whether Probopyrus pandalicola affects the reproductive capability of both male and female daggerblade grass shrimp. The purpose of this study was to determine whether infection by Probopyrus pandalicola resulted in the sexual sterilization of Palaemonetes pugio, and if the reproductive capability of male and/or female shrimp was restored after the bopyrid was removed. We found that parasitized and deparasitized males were able to fertilize the eggs of unparasitized females successfully, as 18.9 ± 7.1% and 42.7 ± 5.2% of the females paired with them became ovigerous in 4 wk, respectively. Neither parasitized nor deparasitized females became ovigerous when placed with unparasitized males during the 4-wk period. However, 45.4 ± 20.6% of deparasitized females did become ovigerous within 10 wk. Despite the fact that female shrimp are able to reproduce again when no longer parasitized, the majority of females remain infected with the bopyrid for their entire lives. Therefore, the sexual sterilization of female shrimp could potentially have a significant impact on estuarine food webs, as grass shrimp are conduits of detrital energy and a food source for many recreationally and commercially important species in estuaries on the East Coast of the United States and in the Gulf of Mexico.

Parasite host specificity has important implications for species diversity estimates, food web dynamics, and host shifts. “White grub” is the metacercaria stage of a fluke (Posthodiplostomum minimum) that occurs in many fish species, but no attempt has been made to quantify variation in host use by this worm. Here we used 2 approaches to evaluate host specificity within the strain that infects centrarchids (P. minimum centrarchi). First, we measured parasite loads in 2 centrarchid hosts, bluegill (Lepomis macrochirus) and white crappie (Pomoxis annularis), from Spring Lake in McDonough County, Illinois. We found that infection levels differed significantly between these hosts. Prevalence in bluegill was 100% and the median intensity was 940 metacercariae, but only 57% of white crappie were infected (median intensity = 4). Site specificity of white grub also differed significantly between the 2 hosts. In bluegills, kidneys were most heavily infected, whereas in white crappies, livers harbored the most worms. We also performed a literature survey of P. minimum prevalence estimates from 14 centrarchid species from other localities. We calculated the mean white grub prevalence for each host species and used this to calculate S_TD*, a quantitative index of host specificity. S_TD* was 1.33, significantly closer to the value for a specialist (S_TD* = 1.00) than a generalist (S_TD* = 2.00). This reflects the fact that P. minimum prevalence is higher in Lepomis species than it is in centrarchids outside this genus. These data show that P. minimum centrarchi specializes on Lepomis species, but the causes of this specialization are unknown. This worm may be a single species that differs in host use due to ecological or physiological host differences, or it may be a complex of species that vary in host use for similar reasons. Genetic data are required to evaluate these possibilities.

The northern fowl mite, Ornithonyssus sylviarum (Canestri & Fanzago), is an ectoparasite of more than 70 species of North American wild birds, but it has a particularly significant impact on chickens, where it is a permanent resident of vent feathers. Improved control practices depend on a better understanding of host–mite relationships. ISA Brown hens were inoculated experimentally with northern fowl mite adults, and northern fowl mite populations developed naturally. Using a fast-response microprobe, temperatures of individual vent feathers (n = 15) were recorded at 5-mm increments along the length of the feather shaft. Immediately after temperatures were recorded, the individual feathers were quickly clipped at the skin surface and then flash-frozen between 2 small blocks of dry ice, freezing all northern fowl mite stages in situ. The feathers then were cut into 5-mm sections for careful mite enumeration by life stage. There were no overall differences among life stages in the distributions on the feather. Mite positions on feathers (distance from skin) varied distinctly with feather zone temperatures, as well as with ambient and average temperatures over the prior 24 hr. Ambient temperature at time of sampling affected the positions of the 2 mobile categories, adults and larvae/nymphs, but showed no statistical relationship with egg distribution. In contrast, ambient 24-hr temperature influenced the positions of all life stages. On-host feather temperatures reflected ambient temperatures. Feathers collected on hot days (ambient temperatures of 23–33 C) provided a narrow and quite warm range of temperature conditions for mites (often >30–36 C). Temperatures on cool days (ambient temperatures of <23 C) provided much wider on-host temperature ranges for mites to occupy (13–35 C). Mites were farther from the skin on warmer days. When mites had a broad range of temperatures, the feather temperature zone occupied by all life stages averaged 28–29 C. Mites move to occupy favorable temperature conditions on-host. When further out on feathers in warm weather, and under thermal stress, northern fowl mites either move off host or are dislodged. They then become a human pest, are noticed by farmers, and are more likely to disperse.

Ticks were collected or recorded from 522 individual reptiles on Dominica and from 658 reptiles from the Bahamas. Two species of ticks were collected on Dominica: Amblyomma antillorum and Amblyomma rotundatum. Similarly, 2 species were collected in the Bahamas: Amblyomma albopictum and Amblyomma torrei. On Dominica, A. antillorum was recorded from 517 Lesser Antillean iguanas (Iguana delicatissima), 2 boa constrictors (Boa nebulosa), 1 Antilles snake (Alsophis sibonius), and 1 Dominican ground lizard (Ameiva fuscata), whereas A. rotundatum was recorded from 1 Lesser Antillean skink (Mabuya mabouya). In the Bahamas, A. albopictum was recorded from 131 Andros iguanas (Cyclura cychlura cychlura), 271 Exuma Island iguanas (Cyclura cychlura figginsi), and 1 Andros curlytail lizard (Leiocephalus carinatus coryi), whereas A. torrei was recorded from 255 Exuma Island iguanas. In the Bahamas, A. albopictum parasitized iguanas on Andros Island and the central Exuma Islands, and A. torrei parasitized iguanas in the southern Exumas. An exception to this trend was that A. torrei was collected from iguanas on Pasture Cay in the central Exumas, an anomaly that is explained by the fact that iguanas (with attached ticks) on Pasture Cay were introduced by humans in the past from islands further south. External hyperparasitic larval erythraeid mites (Leptus sp.) were recorded from A. torrei in the Bahamas.

Two genera of caryophyllidean cestodes, Monobothrium Diesing, 1863 and Promonobothrium Mackiewicz, 1968, from cypriniform fishes (cyprinids and suckers) in the Holarctic Region, are revised using morphological and molecular evidence. Monobothrium, which includes morphologically distinct species that occur in European cyprinids (Cyprinidae) and North American suckers (Catostomidae), is separated into 3 genera. Monobothrium becomes monotypic and is represented by its type species, Monobothrium wageneri Nybelin, 1922, which occurs in European tench, Tinca tinca (Cyprinidae). Monobothrium auriculatum Kulakovskaya, 1961 from Leuciscus danilevskii (Cyprinidae) in the Ukraine, is tentatively transferred to Caryophyllaeus Gmelin, 1790 as Caryophyllaeus auriculatus (Kulakovskaya, 1961) n. comb. because it possesses morphological characteristics considered to be typical of Caryophyllaeus but which are absent in Monobothrium (shape of the scolex, presence of a seminal receptacle, short neck, and absence of a large, muscular papilla surrounding the large gonopores). The 5 remaining Monobothrium species from suckers in North America are transferred to Promonobothrium based on shared morphological features and molecular data. Species of Promonobothrium differ from M. wageneri by having an external seminal vesicle (absent in M. wageneri), the absence of postovarian vitelline follicles in North American species (present in M. wageneri), and a scolex that is digitiform papillate, loculopapillate, or loculotruncate, i.e., equipped with weak loculi and a terminal introvert (vs. claviform, bluntly ended, with 6 weak, shallow, longitudinal grooves in M. wageneri). Phylogenetic analysis of nuclear ribosomal RNA genes ssr- and lsrDNA placed Promonobothrium minytremi within a clade of 3 of the 5 North American Monobothrium species. The position of M. wageneri, although distinct from the remaining Monobothrium species, is unresolved within the Caryophyllidea. This study further supports the pattern that the biogeography of caryophyllidean taxa is generally constrained by host and continental association.

The precise detection of Toxoplasma gondii infection in cats has important public health significance. In the present study, recombinant granule antigen protein GRA7 was evaluated as a potential diagnostic marker for T. gondii infection in cats by an indirect enzyme-linked immunosorbent assay (ELISA), using the classified serum samples from cats, by immunofluorescence assay (IFA) and by modified agglutination test (MAT). There was a perfect agreement (97.2%) between GRA7-ELISA and MAT/IFA (Kappa = 0.92; 95% confidence interval [CI], 0.85 to 0.99), and GRA7-ELISA had a sensitivity of 94.9% and a specificity of 97.9%. No significant difference (P > 0.05) was observed between the detection results by GRA7- and Toxoplasma lysate antigen-based ELISA. Receiver operating characteristic analysis showed a relative sensitivity and specificity of 89.7 and 92.5% at the cut-off value of 0.1 for GRA7-ELISA. These data demonstrate that GRA7 is a promising serodiagnostic marker for T. gondii infection in cats.

Examination of a small portion of the viscera of an oarfish (Regalecus russellii) recovered from Santa Catalina Island, southern California, revealed numerous tetraphyllidean tapeworm plerocercoids, Clistobothrium cf. montaukensis; 2 juvenile nematodes, Contracaecum sp.; and a fragment of an adult acanthocephalan, family Arhythmacanthidae. This suggests that the fish was relatively heavily parasitized. The presence of larval and juvenile worms suggests that oarfish are preyed upon by deep-swimming predators such as the shortfin mako shark, Isurus oxyrinchus, known to be a definitive host for the adult tapeworm, and also by diving mammals such as sperm whales, Physeter catodon L., hosts of Contracaecum spp. nematodes.

Raising goats in settings that are highly contaminated with oocysts of Toxoplasma gondii may contribute significantly to human exposure to this zoonotic parasite. Increasing consumption of young goats in countries where goats are frequently reared in backyards that are also homes to cats (the definitive host of this parasite) elevates such concern. To date, there has been little attention to either the prevalence or genotypic characteristics of T. gondii isolates in young ruminant food animals in Europe. Here, we estimated the prevalence of T. gondii goat-kids raised in backyards and slaughtered for human consumption during Easter. We collected 181 paired samples of serum and diaphragm. Serum samples were analyzed by enzyme-linked immunosorbent assay for antibodies against T. gondii, and muscle tissues were analyzed by polymerase chain reaction to detect T. gondii DNA. Thirty-two diaphragm samples were also bioassayed in mice, and the isolates were genotyped using microsatellite markers. The overall seroprevalence of T. gondii infection in goat-kids was 33.1% (60/181; 95% confidence interval [CI] 26.3–40.5%), and T. gondii DNA was found in 6.1% (11/181; 95% CI 3.1–10.6) of the diaphragm samples. We isolated the parasite from 2 of 32 goat-kids, and the T. gondii strains belonged to genotype II. The results showed that 1/3 of 3-mo-old goats may be infected with T. gondii, and their consumption during Easter (as barbecue) may seriously compromise food safety as a result.

Recently, Pterois volitans, a Pacific species of lionfish, invaded the Atlantic Ocean, likely via the aquarium trade. We examined for internal and external parasites 188 individuals from 8 municipalities of Puerto Rico collected during 2009–2012, 91 individuals from Little Cayman, Cayman Islands, collected during the summers of 2010 and 2011, and 47 individuals from Lee Stocking Island, Bahamas, collected during the summer of 2009. In total, 27 parasite taxa were found, including 3 previously reported species from lionfish, the digenean Lecithochirium floridense, the leech Trachelobdella lubrica, and an Excorallana sp. isopod. We also report another 24 previously unreported parasite taxa from lionfish, including digeneans, monogeneans, cestodes, nematodes, isopods, a copepod, and an acanthocephalan. Among these parasites, several were previously unreported at their respective geographic origins: We report 5 new locality records from Puerto Rico, 9 from Cayman Islands, 5 from the Bahamas, 5 from the Caribbean, and 3 from the subtropical western Atlantic region. Three parasites are reported to associate with a fish host for the first time. The parasite faunas of P. volitans among our 3 study sites were quite different; most of the species infecting lionfish were generalists and/or species that infect carnivorous fishes. Although our study did not assess the impact of parasites on the fitness of invasive lionfish, it provides an important early step. Our results provide valuable comparative data for future studies at these and other sites throughout the lionfish′s invaded range.

Ancient parasite eggs were recovered from environmental samples collected at a Viking-age settlement in Viborg, Denmark, dated 1018–1030 A.D. Morphological examination identified Ascaris sp., Trichuris sp., and Fasciola sp. eggs, but size and shape did not allow species identification. By carefully selecting genetic markers, PCR amplification and sequencing of ancient DNA (aDNA) isolates resulted in identification of: the human whipworm, Trichuris trichiura, using SSUrRNA sequence homology; Ascaris sp. with 100% homology to cox1 haplotype 07; and Fasciola hepatica using ITS1 sequence homology. The identification of T. trichiura eggs indicates that human fecal material is present and, hence, that the Ascaris sp. haplotype 07 was most likely a human variant in Viking-age Denmark. The location of the F. hepatica finding suggests that sheep or cattle are the most likely hosts. Further, we sequenced the Ascaris sp. 18S rRNA gene in recent isolates from humans and pigs of global distribution and show that this is not a suited marker for species-specific identification. Finally, we discuss ancient parasitism in Denmark and the implementation of aDNA analysis methods in paleoparasitological studies. We argue that when employing species-specific identification, soil samples offer excellent opportunities for studies of human parasite infections and of human and animal interactions of the past.

Tomaculocystis corpulenta n. gen., n. sp. (Apicomplexa: Eugregarinorida: Septatorina: Gregarinidae) is described from populations of the little yellow cockroach, Cariblatta lutea (Blattodea: Ectobiidae), established in laboratory culture from samples collected in Alabama and Florida. Tomaculocystis n. gen. are differentiated from other members of Gregarina by a markedly elliptoid gametocyst inside a persistent, lomentiform hyaline epicyst; developmental organization and growth of the spore tubes from gametocyst surface tumidi; and dehiscence by extrusion of non-chain forming oocysts through spore tubes that barely extend beyond the epicyst wall. Gregarina cylindrosa, Gregarina discocephala, and Gregarina mukundai are recognized as members of Tomaculocystis, and G. cylindrosa is recognized as the senior synonym of G. discocephala. Thus, Tomaculocystis cylindrosa n. comb. and Tomaculocystis mukundai n. comb. are formed. Species of Tomaculocystis are distinguished based on gamont deutomerite and oocyst shape and size. The oocysts of T. corpulenta are broadly dolioform, lack 4 polar knobs, and possess distinct, unique polar plates. Oocysts of all other known species in the genus are more oblong in shape, possess 4 polar knobs, and lack the distinct polar plates observed in the oocysts of T. corpulenta. Host utilization and geographic distribution among gregarine genera parasitizing the cockroach family Ectobiidae reveal a pattern of host–parasite specificity linking gregarine genera with ectobiidid subfamilies. Overall patterns suggest a hypothesis of European endemicy for Gamocystis, but hypotheses for the origin and radiation of Tomaculocystis or species of Gregarina infecting cockroaches are confounded by the cosmopolitan spread of pest cockroach species among humans.

A new species of Oligacanthorhynchidae (Acanthocephala) Prosthenorchis cerdocyonis n. sp. is described from 17 specimens collected from the small intestine of the crab-eating fox Cerdocyon thous Linnaeus, 1766 (Canidae: Carnivora) found in the Brazilian Pantanal wetlands. Specimens were studied using light and scanning electron microscopy. Characteristic features distinguishing the new species from others already described are presented, such as size of the body, the position of lemnisci, size of the eggs, host, and geographical distribution. Details of the body surface obtained by scanning electron microscopy, such as the presence of 2 lateral papillae in the proximal region of the proboscis, the presence of barbs in hooks, and a robust and festooned collar, helped to identify the species. Until now, specimens belonging to Prosthenorchis reported from Cerdocyon thous were not identified to species. Furthermore, the new species is the first to be recorded in C. thous found in the Pantanal wetlands.

Hepatozoon is a genus of hemogregarines constituting the most widespread and common reptile hemoparasite. Although various molecular assessments of these parasites have been conducted in lizards from Africa and Europe, similar studies are needed for South American lizards. Through amplification and sequencing of fragments of the 18S rRNA gene, we assess the prevalence of Hepatozoon parasites in 230 geckos from South America, including the endemic species Hemidactylus agrius, Hemidactylus brasilianus, Lygodactylus klugei, Phyllopezus pollicaris, Phyllopezus periosus, and an exotic species, Hemidactylus mabouia. We found an overall low prevalence of Hepatozoon infection (7/230, 3%) with only 3 of the 6 host species infected with Hepatozoon (Hemidactylus mabouia, P. pollicaris, and P. periosus). Within the 7 infected host samples, 5 genetically distinct lineages of Hepatozoon parasites were identified, only 1 of which was similar to previously published haplotypes. Thus, although prevalence is low, genetically based diversity of Hepatozoon in geckos from South America is very high. Three of these lineages appear basal to 1 of the major clades of Hepatozoon, suggesting that this clade might have originated in South America, and thereby indicating a potential phylogeographic pattern that had not been previously identified. Future studies should assess the distribution and competence of invertebrate hosts in the regions analyzed, and Hepatozoon diversity in other less well-known regions of the world.

Over several years of screening diagnostic cases, the Zebrafish International Resource Center Health Services has encountered a myxozoan parasite of the ducts associated with the kidney in zebrafish, Danio rerio, from an average of 21% of facilities submitting specimens over 5 yr. The parasite is coelozoic and is associated with no appreciable histological changes. Plasmodia bear ovoid spores with 3 sutural ridges. Spores are consistent with the genus Myxidium, but they are distinct from any known species and are thus described as Myxidium streisingeri n. sp. Phylogenetically, this parasite is a member of the polyphyletic urinary bladder clade, which is consistent with the site of infection. The common occurrence of a myxozoan in this closed husbandry system is unexpected because these parasites are known to have complex life cycles, alternating between a vertebrate and invertebrate host. It may be that biofilters provide habitat for suitable invertebrate hosts or perhaps M. streisingeri n. sp. can be transmitted directly. Future control of this parasite in zebrafish research laboratories depends on a better understanding of this life cycle.

Tegumentary leishmaniasis (TL) is a zoonotic disease that affects humans and domestic dogs. In Brazil, TL is considered endemic, and Leishmania (Viannia) braziliensis is the prevalent species causing this disease. There is debate about the role of dogs (Canis familiaris) as domestic reservoirs in the transmission cycle of TL. To date, classical parasitological techniques, including parasite isolation in culture media, have been able to detect parasites only from cutaneous lesions. In this study, we detected L. (V.) braziliensis DNA in intact skin fragments collected from 3 naturally infected dogs from the state of Rio de Janeiro, Brazil, with the use of PCR techniques associated with molecular hybridization. The detection of parasitic DNA in this anatomical site is an important finding vis-à-vis the importance of the domestic dogs in endemic areas of TL.

Classification of most monogeneans is primarily based on size, shape, and arrangement of haptoral sclerites. These structures are often obscured or misinterpreted when studied using light microscopy, leading to confusion regarding defining characters. Scanning electron microscopy (SEM) has predominantly been used to study haptoral sclerites in smaller monogeneans, focusing on hooks and anchors. In the Diplozoidae, SEM has not been used to study haptoral sclerites. Using new and modified techniques, the sclerites of diplozoids collected in South Africa were successfully studied using SEM. The digestion buffer from a DNA extraction kit was used to digest the surrounding tissue, and Poly-L-lysine–coated and concavity slides were employed to limit the movement and loss of sclerites, with the latter being more user-friendly. In addition to the success of visualizing the sclerites using SEM, the digested tissue from as little as half of the haptor provided viable genetic material for molecular characterization. From the results presented here, the study of the sclerites of larger monogeneans using SEM, including those bearing clamps, is a viable possibility for future research. Also, this method may be beneficial for the study of other, non-haptoral sclerites, such as cirri in other families of monogeneans. During this study, Labeo capensis was noted as a valid host of Paradiplozoon vaalense in a region of the Vaal River where the type host, Labeo umbratus, appears to be absent.

Northern bobwhite (Colinus virginianus) have experienced a dramatic decline in West Texas over the last 3 yr, and investigations are underway to evaluate the role of parasites in this decline. One of the key parasites being investigated is the eyeworm (Oxyspirura petrowi). Live eyeworms were extracted from both live and dead northern bobwhites, and in vitro survival was tested using 10 liquid media. Eyeworms placed in an egg white and physiological saline solution lived for at least 36 days. Live O. petrowi placed into the eyes of uninfected pen-raised bobwhites were monitored for 21 days to demonstrate successful transfer. Eyeworm behavior during feeding, mating, and development were monitored. This study is important to research that requires “banking” of live O. petrowi from wild-captured definitive hosts for life history studies and assessing the impact of O. petrowi on host individuals.

A new method to amplify coccidia DNA by polymerase chain reaction (PCR) was developed by placing freeze-thawed oocysts in Ready-to-Go PCR bead tubes and using a 5-min initial heat denaturation step. Positive PCR reactions were found in 3 of 3 samples containing 20 or 50 oocysts; when ≤5 oocysts were used, 1 of 3 samples was positive. This technique shows potential for effectively and efficiently detecting and identifying oocysts from soil, feces, and other matter.

Pond snails (Physa acuta) were exposed to a gradient (0, 1, 3, 5, 10, 15, 20, 25, 30, 35, 40, and 50) of trematode (Halipegus eccentricus) eggs and observed to determine egg dose effects on the survival of snails through the prepatent period, snail reproduction, and the production of cercariae. The probability of snail survival through the prepatent period significantly decreased with increasing egg exposures, where the odds of snail survival was 0.94 per trematode egg. Similarly, the probability of snail reproduction significantly decreased with increasing egg exposures, where the odds of snail reproduction was 0.85 per trematode egg. In contrast, the probability of a snail shedding cercariae significantly increased with increasing egg exposures, where the odds of reaching a patent infection were 1.64 per trematode egg. However, snails shedding cercariae that were exposed to higher doses of trematode eggs tended to die sooner. Thus, there appears to be a tradeoff between infecting a snail and killing the host.

Despite the large number of reports of species of Clinostomum from vertebrate hosts in South America, studies evaluating the molluscan transmitters of these parasites are scarce. In the present study, clinostomatoid cercariae shed from 0.02% (4/17,485) specimens of Biomphalaria spp., collected at the Pampulha reservoir, Belo Horizonte, Minas Gerais, Brazil, were used for experimental infection of Poecilia reticulata. Samples of cercariae from molluscs and metacercariae experimentally obtained from fish were subjected to morphological and molecular analyses and compared with species of Clinostomum reported in the Americas. The cercariae and metacercariae, here identified as Clinostomum sp., present general morphology similar to that reported for Clinostomum marginatum, however, from molecular point of view, differ significantly from North American C. marginatum and other species of Clinostomum reported in South America. These results suggest that the diversity of Clinostomum found in Brazil may be underestimated. Additional studies aimed at molecular characterization of South American species of Clinostomum, including the finding of specimens with sequences similar to that reported for C. marginatum in North America are required.

The present study evaluated the pathogenicity of Baylisascaris potosis, a newly described ascarid nematode, in Mongolian gerbils. Gerbils were infected with varying doses of either B. potosis or Baylisascaris transfuga embryonated eggs (100, 1,000, and 4,000) for 30 days postinfection (pi). Baylisascaris potosis–infected gerbils showed no clinical signs of disease; however, gerbils exposed to 1,000 and 4,000 B. transfuga eggs showed severe neurologic signs at 22–29 days and 14–15 days pi, respectively. Histopathologic examination revealed larvae and lesions in the intestine, lung, liver, and muscles of B. potosis–infected gerbils, but not in the brain, whereas B. transfuga larvae were found only in the brain and muscle. These results indicate that B. potosis larvae migrate through numerous organs and are associated with visceral larva migrans in gerbils, but less frequently migrate to the nervous system in gerbils than does B. transfuga.

In 1984, work on the parasite population and community ecology in the pulmonate snail, Helisoma anceps, was initiated in Charlie's Pond (North Carolina). Similar research on Physa gyrina was started in 1986. When study in the pond began in 1984, 8 species of larval trematodes were being shed from Hel. anceps. By far, the dominant species was Halipegus occidualis, with prevalences generally ∼60%, except during midsummer, when older snails were dying. For the other 7 trematode species being shed, prevalences were consistently less than 4%. By 2006, 18 species had been identified in Hel. anceps at one time or another. In 1986, Hal. eccentricus was discovered in P. gyrina, with a prevalence of ∼49%. Through 2006, 7 trematodes were found to be shedding cercariae from P. gyrina. Halipegus eccentricus disappeared from the pond in 1998. From March through November of 2012 and 2013, 1,292 Hel. anceps and 716 P. gyrina were collected, using collection protocols that were identical to those used from 1984 through 2006. In 2012, 5 trematode species, including Hal. occidualis, were present in Hel. anceps at one time or another. During the last part of the 2012 collecting season cercariae of just 2 species were being shed from Hel. anceps (and 1 from P. gyrina). In 2013, only cercariae of Haematoloechus longiplexus and Uvulifer ambloplitis were observed from Hel. anceps. The latter species was lost by 2014, and an echinostome was present (2.1%); a single snail was infected with Haem. longiplexus. Four species were being shed from P. gyrina, i.e., Echinoparyphium sp. (7.9%), Glypthelmins sp. (1.5%), Plagiorchis sp. (4.9%), and Posthodiplostomum sp. (7.4%). Rarefaction curves were generated for Hel. anceps shedding in 1984, 1988, 1989, 2002, 2006, and August of 2014. The data clearly indicate that species diversity was constantly declining over the 31-yr period. We did not include P. gyrina in the analysis since data for this snail species were not acquired until 1991–1992. At present, we have no definitive explanation for the decrease in diversity, although circumstantial evidence suggests that it might be related to periodic declines in water level that negatively affected the colonization and maintenance of emergent vegetation within the pond.