The last half-century has provided all of the (few) drugs currently used to treat human helminthiases. Concern regarding the long-term utility of these drugs, given how readily resistance evolves in the veterinary-agricultural sector, spurs the discovery of new chemical entities. We review the approaches and technologies in use to identify anthelmintics and discuss a number of drug discovery paradigms that may prove pivotal to the next half-century of anthelmintic development.

Trematodes belonging to the family Stomylotrematidae are intestinal parasites of birds. Despite the worldwide distribution and diversity of host species, the first intermediate host remains unknown. For a survey of parasites of Pomacea maculata, snails were collected from the municipality of São Vicente Férrer, state of Maranhão, northeastern Brazil. In the present study, the xiphidiocercariae shed from these snails were used in the experimental infection of the water bug Belostoma plebejum. The insect mortality was observed 30 days post-infection, and the metacercariae recovered in the body cavity of B. plebejum were identified as Stomylotrema gratiosus. This is the first report of an ampullariid snail as intermediate host of stomylotrematid trematodes.

Linognathus samburi n. sp. is described from adult male and female specimens collected from a juvenile female Günther's dikdik (Madoqua guentheri) live-trapped near Olturot Village, Samburu district (Rift Valley Province) in northern Kenya. The new species is distinguished from other species of Linognathus including Linognathus geigyi and Linognathus damarensis, both of which parasitize Kirk's dikdik (Madoqua kirkii). A dichotomous key to the species of Linognathus that are known to parasitize dikdiks is included.

Neotyphloceras crassispina hemisus Jordan is redescribed from male and female specimens collected at the type locality (Otro Cerro, Catamarca Province, Argentina) and nearby localities. New diagnostic morphological characters for both sexes are provided, which include the shape of the upper lobe of the fixed process of clasper, the crochet of the aedeagus and the shape and chaetotaxy of the distal arm of sternum IX for males, and the contour of the distal margin of sternum VII for females.

Ectoparasitic arthropods are often vectors of rickettsiosis. We conducted a survey of ectoparasites on U.S. military facilities throughout Japan with the use of specimens submitted by pest control, public health, and veterinary personnel. Over 1,600 individual ectoparasites were collected. Fifteen species were identified, including several significant vectors of human diseases such as scrub typhus and rickettsial spotted fevers. These ectoparasites included Ctenocephalides felis, Haemaphysalis longicornis, Ixodes persulcatus, Leptotrombidium fuji, Leptotrombidium pallidum, and Rhipicephalus sanguineus. Rickettsial agents were detected by PCR and DNA sequencing. These included Bartonella henselae, Bartonella japonica, a novel Bartonella, Coxiella burnetii, an unnamed Coxiella, Ehrlichia canis, Orientia tsutsugamushi, Rickettsia typhi, and “Rickettsia Rf2125”/“Rickettsia cf1and5”.

Angiostrongylus cantonensis , the rat lungworm, is a zoonotic, parasitic nematode that uses the rat as a definitive host and gastropods as intermediate hosts. It is prevalent in parts of Asia, the Pacific islands, and the Caribbean. In the United States, A. cantonensis is established in Hawaii and in recent years has been reported in Alabama, California, Louisiana, and Florida, where it has been found in the reintroduced Lissachatina fulica (also known as Achatina fulica), the giant African snail that was once eradicated from the state. Since 2004, A. cantonensis has been identified as the causative agent for 2 non-human primate deaths in Florida, one attributed to ingestion of the snail Zachrysia provisoria. Our study further supports the presence of A. cantonensis in Z. provisoria in Florida and identifies 2 additional introduced terrestrial snails, Bradybaena similaris and Alcadia striata, that serve as intermediate hosts for A. cantonensis, as well as evidence of rat infection, in southern Florida. The finding of both definitive and intermediate hosts suggests that A. cantonensis may be established in south Florida.

Canine babesiosis constitutes a major global veterinary medical problem caused by tick-borne hemoparasites Babesia gibsoni and Babesia canis. Babesia gibsoni induces more severe clinical signs and is mainly transmitted by the ixodid Haemaphysalis longicornis. In Japan, B. gibsoni is primarily found in the western districts, with few records in the eastern parts. The aim of the current investigation was to evaluate distribution patterns of B. gibsoni infection in 9 Japanese islands and peninsulas using direct microscopy and PCR. Therefore, 196 hunting dogs were randomly sampled during the period from March to September 2011. Ages and sexes of dogs were identified. Direct microscopy of Giemsa-stained blood smear revealed pear-shaped piroplasms of B. gibsoni in 3 (1.6%) dogs. PCR was done initially with the universal primer set (B18S-F and B18S-R) amplifying the 1,665-bp portion of the 18S rRNA gene, followed by the specific primer set (Bg18F1 and Bg18R2) amplifying 2,363-bp fragments of the same gene. Accordingly, 84 (42.9%) and 8 (4.1%) dogs were positive, respectively. The current investigation shows that canine babesiosis was recorded in all islands except for Sado Island, Atsumi Peninsula, and Tanegashima Island. The highest infection rate was detected in the main island of Okinawa, while the lowest was on Ishigaki Island. Both sexes were non-significantly infected. However, the diversity of infection in islands was significantly different (P < 0.05). Although B. gibsoni has been previously found in western and eastern Japan, the present work highlights the prevalence of infection in many Japanese districts, including islands and peninsulas, giving realistic data that can facilitate treatment and control.

This paper aims to resolve the dual composition of the triakid shark–hosted tetraphyllidean genus Calliobothrium—an issue that has been recognized for over a decade. As it stands, this genus includes a number of large species with laciniate proglottids, most of which bear 3 suckers at the anterior margin of each bothridium, but it also includes a number of species that lack proglottid laciniations and bear only a single sucker per bothridium, most of which are relatively small. Discovery of 2 new species, 1 of each form, parasitizing the whitespot smoothhound shark, Mustelus palumbes, off South Africa, prompted the first molecular analysis of the genus. Bayesian inference and maximum likelihood analyses of 28S rDNA (D1–D3) sequence data generated for specimens of both new species as well as of 2 known species of the laciniate form (Calliobothrium australis and Calliobothrium cf. verticillatum) and 3 known species of the non-laciniate form (Calliobothrium violae, Calliobothrium riseri, and Calliobothrium barbarae) confirmed the reciprocal monophyly of the 2 clades, supporting establishment of a new genus. Because the type of Calliobothrium, C. verticillatum, is of the laciniate form, Symcallio n. gen., with Symcallio peteri n. gen., n. sp., from M. palumbes described as its type, is established to house members of the non-laciniate clade. The 11 described species consistent with this form are transferred to the new genus. A new species of the laciniate clade, Calliobothrium euzeti n. sp., is described from M. palumbes, and a revised diagnosis of Calliobothrium is presented.

The hookworms Uncinaria rauschi Olsen, 1968 and Uncinaria yukonensis (Wolfgang, 1956) were formally described from grizzly (Ursus arctos horribilis) and black bears (Ursus americanus) of North America. We analyzed the intestinal tracts of 4 grizzly and 9 black bears from Alberta and British Columbia, Canada and isolated Uncinaria specimens with anatomical traits never previously documented. We applied morphological and molecular techniques to investigate the taxonomy and phylogeny of these Uncinaria parasites. The morphological analysis supported polymorphism at the vulvar region for females of both U. rauschi and U. yukonensis. The hypothesis of morphological plasticity for U. rauschi and U. yukonensis was confirmed by genetic analysis of the internal transcribed spacers (ITS-1 and ITS-2) of the nuclear ribosomal DNA. Two distinct genotypes were identified, differing at 5 fixed sites for ITS-1 (432 base pairs [bp]) and 7 for ITS-2 (274 bp). Morphometric data for U. rauschi revealed host-related size differences: adult U. rauschi were significantly larger in black bears than in grizzly bears. Interpretation of these results, considering the historical biogeography of North American bears, suggests a relatively recent host-switching event of U. rauschi from black bears to grizzly bears which likely occurred after the end of the Wisconsin glaciation. Phylogenetic maximum parsimony (MP) and maximum likelihood (ML) analyses of the concatenated ITS-1 and ITS-2 datasets strongly supported monophyly of U. rauschi and U. yukonensis and their close relationship with Uncinaria stenocephala (Railliet, 1884), the latter a parasite primarily of canids and felids. Relationships among species within this group, although resolved by ML, were unsupported by MP and bootstrap resampling. The clade of U. rauschi, U. yukonensis, and U. stenocephala was recovered as sister to the clade represented by Uncinaria spp. from otariid pinnipeds. These results support the absence of strict host–parasite co-phylogeny for Uncinaria spp. and their carnivore hosts. Phylogenetic relationships among Uncinaria spp. provided a framework to develop the hypothesis of similar transmission patterns for the closely related U. rauschi, U. yukonensis, and U. stenocephala.

Six new species of Leptorhynchoides from the southeastern United States are described. These new species were once part of the Leptorhynchoides thecatus complex of species that was previously recognized on the basis of DNA sequence data. Multivariate morphometric analysis including discriminant function analysis and decision tree analysis indicated that each of the species is morphologically distinct. Both analyses classified more than 90% of specimens correctly and most misclassifications occurred between members of 2 pairs of species that are morphologically similar. The most discriminating continuous characters were: trunk length, number of longitudinal rows of hooks, length of the longest hook, and testes width. Hook asymmetry and missing hooks on the proboscis were also important taxonomic characters. The discriminant function and the decision tree generated from the data were used to classify new specimens, yielding a 96% and 84% correct classification rate, respectively. The new taxonomic designations account for much of the previously recognized variability in host use, habitat use, and development as determined by survey data. With the addition of these 6 new taxa, 10 species currently are recognized within the genus.

Two new species of Parapharyngodon Chatterji, 1933, parasitizing 3 species of hylid frogs (Diaglena spatulata, Triprion petasatus, and Trachycephalus typhonius) from Mexico are described. The 2 new species share the presence of a gubernaculum with Parapharyngodon lamothei and belong to the group of those species with short spicule; both differ from the remaining species of the genus in the papillar pattern on ventrolateral and dorsal lips and in the thickness of cuticular annulations and cuticular ornamentation in the female specimens. These are the third and fourth reports of Parapharyngodon spp. parasitizing hylid frogs. In addition to the egg characteristics, we propose that length of the lateral alae is also a taxonomically relevant feature to differentiate species of the genus. A bibliographic review of all species historically assigned to Parapharyngodon is given, including those that have been declared species inquirenda, or transferred to other genera and those that are considered valid.

In a study of 106 sunfish, Mola mola (L.), from Mediterranean waters, 2,731 worms, belonging to 2 congeneric species of accacoeliids, Accacladocoelium macrocotyle (Diesing, 1858) Robinson, 1934 and Accacladocoelium nigroflavum (Rudolphi, 1819) Robinson, 1934, were collected from the digestive system. It is often difficult to differentiate between these 2 species as they are sympatric and very similar; in fact, according to previous descriptions, the extent of the vitellarium is the only interspecific difference, described as extending posteriorly to the ovary in A. macrocotyle and as anterior to the anterior testis in A. nigroflavum. However, this diagnostic trait is not always valid; moreover, it is often indistinguishable because it is masked by the uterine eggs. Here, the morphology of new specimens of both species has been studied in detail and combined with molecular analysis. This study shows that the extension of the vitellarium is very similar in both species, but the degree of ramification differs. Furthermore, although the morphological differences are very slight, both species seemed genetically different: intraspecific differences ranged between 0.8 and 1.5% in internal transcribed spacer (ITS)-2 rRNA gene (ITS2) and between 0.5 and 1.6% in cytochrome c oxidase subunit 1 (COI) and interspecific differences ranged between 2 and 3.2% in ITS2 and between 9.6 and 10.6% in COI. In addition, we observed previously undescribed morphological differences, which help to differentiate these 2 species: the oral sucker is relatively smaller in A. nigroflavum than in A. macrocotyle and the ovary is usually relatively longer in A. nigroflavum than in A. macrocotyle.

Amoebiasis, caused by Entamoeba histolytica, has a worldwide distribution and is of public health significance in many developing countries. It has a fecal–oral transmission cycle and is most prevalent in developing countries in regions where substandard sanitary conditions exist due to poverty. Little is known about the epidemiology of E. histolytica infection and its presence in different socioeconomic communities in developing countries. We undertook the present study in the city of Lahore, Pakistan, and our prediction was that the prevalence of E. histolytica-like cysts and E. histolytica stool antigen would be lower in patients from upper socioeconomic levels than in individuals from middle or lower socioeconomic levels. We investigated the prevalence of E. histolytica in humans from 3 socioeconomic communities in territories of Lahore, Pakistan. Six hundred fecal samples were collected and examined using both microscopy (triple fecal test) to detect cysts of E. histolytica-like amoeba and ELISA (stool antigen ELISA) to demonstrate diagnostic stool antigens of E. histolytica. Samples were from individuals living under conditions deemed to be upper socioeconomic class (n = 287), middle socioeconomic class (n = 172), and lower socioeconomic class (n = 141). The total prevalence of positive samples was 22.5% (135/600) by triple test and 16.8% (101/600) by stool antigen ELISA in the 600 fecal samples. Statistically, significant (P < 0.05) differences in prevalence were seen between the 3 socioeconomic class groups. Forty-four (15.3%) and 32 (11.1%) of 287 in the fecal samples from the upper socioeconomic class were positive by triple test and by antigen ELISA, respectively. Thirty-nine (22.6%) and 29 (16.8%) of 172 in the fecal samples from the middle socioeconomic class were positive by the triple test and by antigen ELISA, respectively. Fifty-two (36.8%) and 40 (28.3%) of 141 in the fecal samples from the lower socioeconomic class were positive by the triple test and by antigen ELISA, respectively. We accept our hypothesis based on these findings. We also demonstrated that fecal samples collected from the youngest age group (1 mo–5 yr) were more likely to be positive for E. histolytica antigens than were samples from the other 3 age groups, and that prevalence was significantly higher (P < 0.05) in the summer than in the other 3 seasons. These results highlight the importance of surveillance of this relatively ignored pathogen in this developing metropolitan city in Pakistan.

Parasite prevalence in predatory mammals is influenced by numerous factors including diet, sex, season, and habitat. We examined the effect of such factors on the prevalence of gastrointestinal helminths in North American river otters (Lontra canadensis) in Yellowstone Lake, Yellowstone National Park. Otters in this ecosystem have recently experienced a decline in their main prey, Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri), and have, in turn, increased consumption of alternative foods. Helminths were found in 13.2% of otter fecal samples. The dominant parasite was a Diphyllobothrium sp. (Diphyllobothrium ditremum or Diphyllobothrium dendriticum), a cestode acquired from cutthroat trout. Truttaedacnitis truttae and Contracaecum spp. nematodes were incidental parasites in otter feces, and acanthocephalan eggs were found in 1 sample. The prevalence of trout remains and a Diphyllobothrium sp. in otter feces was higher during the cutthroat trout spawning season. A Diphyllobothrium sp. was more prevalent in the feces of female otters. There was no relationship between annual declines in the frequency of trout in otter feces and prevalence of parasites. Helminth prevalence and species richness in Yellowstone otters was low and likely reflects low predator densities and few intermediate hosts. This is the first study reporting the helminth fauna of river otters in the Greater Yellowstone Area and confirms the otter as a definitive host for Diphyllobothrium sp. in this region.

The aim of this study is to investigate renal involvement in schistosomiasis. This is a retrospective cohort of 60 consecutive patients with schistosomiasis admitted to a university hospital in Maceió, Brazil. The patients were divided into 2 groups: patients with and without acute kidney injury (AKI) according to the RIFLE criteria. We compared the groups for differences in clinical manifestations and laboratory tests. Patients' mean age was 58 ± 16 yr, and 56.7% were female. The average length of hospital stay was 16.4 ± 12.1 days. Patients with hypertension and diabetes were 35% and 21.7% respectively. The main clinical symptoms and signs presented were ascites (86.7%), splenomegaly (80%), and hepatomegaly (63.3%). Current or previous history of upper gastrointestinal bleeding was found in 45% of patients, esophageal varices on endoscopy were present in 92%, and periportal fibrosis on ultrasound examination in 81% of patients. AKI incidence was 43.3% during hospital stay. Mean age and length of hospitalization were higher in the AKI group. Diuretic use, such as furosemide and spironolactone, ascites, and AST levels were also associated with AKI. Death occurred in 5 cases (8.5%), 4 of them in the AKI group. The classifications Child-Pugh score (CHILD) and Model for End-Stage Liver Disease (MELD), used to assess the severity and prognosis of chronic liver disease, presented higher scores among patients with AKI (CHILD: 9.5 ± 1.5 vs. 8.4 ± 1.7, P = 0.02; MELD: 19 ± 5.8 vs. 13 ± 3.9, P < 0.001). Renal dysfunction is an important feature of schistosomiasis, which is associated with significant morbidity and possible increased mortality. Further studies are necessary to establish the mechanisms through which schistosomiasis can lead to renal dysfunction.

The parasitic fauna of cetaceans is an important tool for ecological studies, including analyses on the causes of death. Halocercus brasiliensis is a nematode frequently found in the bronchi and bronchioles of some cetaceans, and it is commonly associated with focal inflammation of the respiratory tract leading to bacterial pneumonia and septicemia and, sometimes, to death. The objective of this study was to report infections by H. brasiliensis in the respiratory tract of Delphinidae stranded on the northern seaside of Bahia, Sergipe, and south of Alagoas, all states in the northeast region of Brazil. A total of 30 individuals, 1 Feresa attenuate (pygmy killer whale), 9 Stenella clymene (Clymene dolphin), and 20 Sotalia guianensis (Guiana dolphin) were studied. In 16 of them, the presence of H. brasiliensis was observed with a mean intensity of 3.5 ± 0.6 (range 1–9) in the hosts. Macroscopically, parasitic calcified nodules, lung congestion, edema, and emphysema were observed. Histopathological examination showed interstitial and granulomatous pneumonia with multifocal infiltrates, discrete to moderate edema, congestion, diffuse hemorrhage, and foci of calcification. We conclude that parasitic pneumonia in the sampled individuals may have directly contributed to stranding and death of the animals.

Focusing upon chewing lice (Phthiraptera: Amblycera, Ischnocera) parasitizing blackcaps (Sylvia atricapilla) in the Azores (Portugal), we found a lower number of louse species in the Azores compared to mainland Europe. Only chewing lice host specific to blackcaps were found in the Azores. Louse prevalences were much higher in blackcaps from the Azores compared to those of various mainland populations. Chewing lice are permanent parasites of birds, and for such parasites the parasite island syndrome could be characterized by higher parasite prevalence on the islands compared to the mainland.