The brown booby (Sula leucogaster Boddaert, 1783) has a wide geographic distribution, being found throughout the intertropical range except for the west coast of South America. Chewing lice (Phthiraptera: Amblycera and Ischnocera) are ectoparasites commonly found in association with a wide variety of bird species, and extensive infestations can lead to severe itching and irritation that causes skin lesions, damage to the plumage, and abandonment of nests. Sula leucogaster lice have an atypical distribution, not fully following the distribution of their host. In the years 2018 and 2019, 4 marine animal rehabilitation centers located in Rio de Janeiro and São Paulo, Brazil received live birds and carcasses of Sula leucogaster. The animals were deloused and lice of 2 different species were collected. Identification was performed by optical microscopy, and the species found were Eidmanniella albescens Piaget, 1880 and Pectinopygus garbei Pessoa and Guimarães, 1935. This is the first record of both species in Rio de Janeiro.

Babblers (Passeriformes: Leiothrichidae, Pellorneidae, Timaliidae) are parasitized by more genera of lice of the Brueelia complex than any other group of songbirds. However, the relationships of these louse groups are poorly known. We here try to resolve the relationships between Guimaraesiella (Guimaraesiella), Guimaraesiella (Cicchinella), and their putative sister group Priceiella by using mitochondrial cytochrome c subunit 1 (COI), 12S, and 16S sequences. Our data indicate that G. (Cicchinella) forms a monophyletic group of lice from babblers, but the relationship between G. (Guimaraesiella), G. (Cicchinella), and Priceiella could not be resolved. Moreover, the position of the third lineage of babbler-specific lice, containing only the aberrant species Guimaraesiella montisodalis, is unresolved. Morphologically, this species is different from all other Guimaraesiella in several characters and may represent a distinct lineage. We present some data indicating that (1) the Nanling Mountain range may be a biogeographical barrier to chewing lice and (2) host participation in mixed-species feeding flocks may influence host associations in Brueelia-complex chewing lice.

Michajlovia turdi (Yamaguti, 1939) (Digenea: Brachylaimoidea) has been found from the Japanese thrush, Turdus cardis Temminck, 1831, in Hokkaido, the northernmost island of Japan. This is a rediscovery of M. turdi in Japan after approximately 80 years from the original description of the species as Leucochloridium turdi Yamaguti, 1939. Here we redescribe the morphology of M. turdi and generate DNA barcodes for the species by sequencing nuclear ribosomal RNA (18S and 28S) and mitochondrial cytochrome c oxidase subunit I (COI) genes. Our molecular phylogenetic analysis was not effective at determining the taxonomic rank of Michajlovia in Brachylaimoidea, and consequently the genus remains as incertae sedis.

In this article, we present 2 case reports of puppies less than 4 mo of age at the time of infection with the nematode known as giant red kidney worm (Diotophyma renale). The first puppy was prepared for an ovariohysterectomy that evolved into an exploratory laparotomy. An inflamed omentum was observed, and D. renale infection was suspected due to the puppies' place of origin. The algorithm developed by the Ontario Society for the Prevention of Cruelty to Animals for the diagnosis and treatment of D. renale infections in dogs was followed. Both puppies had a history of origin from northern Manitoba, Canada. Due to the puppies' ages, the authors suspect that the transmission of infection for both puppies could be transmammary, transplacental, or ingestion of paratenic hosts or that these cases challenge what is thought to be the current prepatent period. In addition, D. renale infections in dogs, especially from northern communities, could be common.

An abundance of morphologically variable Henneguya species complicates the understanding of disease relationships between ictalurid catfish and myxozoan (Phylum: Cnidaria) parasites on North American aquaculture operations. Henneguya ictaluri, the cause of proliferative gill disease (PGD) in channel and hybrid catfish, is arguably the most important parasite of commercial catfish aquaculture in the southeastern United States. While research indicates arrested development and limited sporogenesis of H. ictaluri in channel (Ictalurus punctatus) × blue (Ictalurus furcatus) hybrid catfish, incidents of PGD persist in hybrid production systems. This work investigated the influence of fish host on myxozoan community composition and diversity within naturally infected gill tissues from diagnostic case submissions to the Aquatic Research and Diagnostic Laboratory in Stoneville, Mississippi, from 2017 to 2019. Gills collected from farm-raised catfish with clinical PGD were subjected to metagenomic amplicon sequencing of the myxozoan 18S SSU rDNA gene diagnostic variable region 3 (DVR3). Myxozoan community composition significantly differed between channel and hybrid catfish PGD cases, with channel catfish having more diverse community structures. Channel catfish gills had a greater relative abundance of H. ictaluri in 2017 and 2019, while no differences were observed in 2018. Importantly, H. ictaluri was present in all channel and hybrid catfish PGD cases across all years; however, H. ictaluri was not the most abundant myxozoan in almost half the cases examined, suggesting other myxozoan species may also contribute to PGD pathology. The detection of numerous known and unclassified myxozoan sequences in addition to H. ictaluri provides evidence PGD may involve mixed species infections. Furthermore, the presence of numerous unclassified myxozoan sequences in gill samples from clinical PGD cases indicates the number of described species from U.S. farm-raised catfish vastly underestimates the true myxozoan diversity present within the varied pond microcosms associated with catfish aquaculture.

The echinostomatid Drepanocephalus spathans (syn. Drepanocephalus auritus) parasitizes the double-crested cormorant Phalacrocorax auritus. In North America, the marsh rams-horn snail Planorbella trivolvis and ghost rams-horn snail Biomphalaria havanensis serve as snail intermediate hosts, both of which inhabit catfish aquaculture ponds in the southeastern United States. Studies have demonstrated D. spathans exposure can be lethal to juvenile channel catfish Ictalurus punctatus. Two studies were undertaken to elucidate the life cycle of D. spathans to establish a developmental time line. In both studies, D. spathans cercariae collected from naturally infected P. trivolvis individuals were used to infect channel catfish fingerlings, which were then fed to double-crested cormorants (DCCOs) that had been pharmaceutically dewormed. In study 1, laboratory-reared P. trivolvis and B. havanensis individuals were placed in aviary ponds with experimentally infected DCCO and examined bi-weekly for release of cercariae. Trematode eggs were observed in the feces of exposed birds 3 days post-infection. Birds were sacrificed 18 days post-exposure (dpe), and gravid adults morphologically and molecularly consistent with D. spathans were recovered. Snails from the aviary pond were observed shedding D. spathans cercariae 18–54 dpe. In study 2, trematode eggs were observed in the feces of exposed DCCOs beginning 8 dpe. Once eggs were observed, birds were allowed to defecate into clean tanks containing naïve laboratory-reared P. trivolvis individuals. Additionally, eggs from experimental DCCO feces were recovered by sedimentation and placed in an aquarium housing laboratory-reared P. trivolvis individuals. Birds in study 2 were sacrificed after 60 days, and gravid D. spathans specimens were recovered. Snails from the experimental DCCO tanks shed D. spathans cercariae 89–97 dpe. Lastly, trematode eggs were isolated and observed for the hatching of miracidia, which emerged on average after 16 days at ambient temperatures. No D. spathans adults were observed in control birds fed non-parasitized fish. This is the first experimental confirmation of the D. spathans life cycle, resolving previously unknown developmental time lines. In addition, the effects of fixation on adult trematode morphology were assessed, clarifying reports of pronounced morphological plasticity for D. spathans.

The serum ferritin (SF) levels of patients with hepatic alveolar echinococcosis (HAE) were compared to the laboratory reference value, and the correlation between SF and associated parameters in patients with HAE was assessed. Hematological and imaging data of 245 patients with HAE were collected. Patients were classified into the LSF group (SF ≤ 204 ng/ml) or HSF group (SF > 204 ng/ml) according to the level of SF. There was no significant difference in the serum iron level between groups (P > 0.05). Significant differences in unsaturated iron-binding capacity (UIBC), liver function, blood coagulation, lipid, blood cell count, and lesion characteristics were observed (P < 0.05). Correlation analysis showed that SF was related to UIBC, γ-glutamyl transferase, total bilirubin (TBIL), direct bilirubin (DBIL), fibrinogen (FIB), neutrophil count, and maximal lesion diameter (all absolute r_s ≥ 0.4). The correlation coefficient between SF and UIBC showed the highest absolute value (r_s = –0.556, P < 0.001). Single-factor linear regression analysis showed that TBIL and DBIL showed the R² values were 0.221 and 0.220, and the R² values of UIBC, FIB, and maximal lesion diameter were 0.157, 0.174, and 0.167, respectively, and those of the remaining indicators were <0.1. Multi-factor binary logistic regression analysis showed that UIBC (P < 0.001, OR = 0.909), FIB (P = 0.020, OR = 1.662), hemoglobin (HGB) (P = 0.002, OR = 1.029), and maximal lesion diameter (P = 0.002, OR = 1.146) were significant factors influencing SF abnormalities. SF levels in some patients with HAE were higher than the laboratory reference value. Correlation and regression analysis of SF suggested that the UIBC, FIB, HGB, and maximal lesion diameter were related to SF and affected the SF level. These results may be helpful for the diagnosis and severity assessment of HAE in the future.

A study of cestode specimens that were collected during survey work on elasmobranchs collected from Taiwan and Northern Territory, Australia, revealed the presence of 1 new combination into the genus Stillabothrium (Rhinebothriidea: Escherbothriidae) and 2 new species of the genus. Phyllobothrium biacetabulatum, collected from Rhinobatos schlegelii, is transferred to Stillabothrium and its description is emended, as is the diagnosis for the genus Stillabothrium and the family Escherbothriidae. Stillabothrium biacetabulatum n. comb. differs from existing species of the genus in that the face of its bothridia is laced with a network of longitudinal and horizontal muscle fibers that do not contribute to the formation of septa. Stillabothrium lunae n. sp. is described from Himantura leoparda and differs from existing species of the genus in that its bothridium possesses an anterior field of 7–8 loculi that are wider than long. Stillabothrium mariae n. sp. is described from Maculabatis astra. This species differs from all species of Stillabothrium except Stillabothrium campbelli in possessing 10–12 horizontally oriented bothridial loculi. Stillabothrium mariae n. sp. differs from S. campbelli in having longer bothridia and from all other species of Stillabothrium in that it lacks, rather than possesses, conspicuous septa and loculi that are longer than wide in the posterior region of its bothridia. Bayesian and parsimony-bootstrap analysis of 28S rDNA revealed S. biacetabulatum n. comb., S. lunae n. sp., and S. mariae n. sp. to be part of Clade 1 of Stillabothrium, with S. biacetabulatum n. comb. being the sister species to S. mariae n. sp. Stillabothrium lunae n. sp. was found to be the sister species to Stillabothrium borneoense.

Dioctophyme renale has a worldwide distribution and has been diagnosed in several wild and domestic animals as well as in humans. As numerous reports in the literature exist concerning the presence of D. renale in different animal species, as well as its diagnosis, treatment, and confirmation in new geographic areas, we reviewed existing information to contribute to the knowledge of the etiology, biology, epidemiology, pathogenesis, symptoms, diagnosis, treatment, and prevention of D. renale. Results of dioctophymosis may range from asymptomatic infection to even death of the host. Diagnosis is based on data from morphology, imaging, and antibody testing, with surgical treatment being the most effective. A high potential for infection of pets exists when there is overlap with wild parasitized animals; given common risk factors for infections in humans, D. renale should be considered as having zoonotic potential.

Grouse and ptarmigan (Galliformes) harbor fairly diverse helminth faunas that can impact the host's health, including filarial nematodes in the genus Splendidofilaria. As host and parasite distributions are predicted to shift in response to recent climate change, novel parasites may be introduced into a region and impose additional stressors on bird populations. Limited information is available on the prevalence of filariasis in Alaska galliforms. To date, no molecular surveys have been completed. Past studies relied on examining blood smears or total body necropsies, which are time-consuming and may not detect filarial parasites with low prevalence in hosts. Therefore, we developed a TaqMan probe-based real-time PCR assay targeting the cytochrome c oxidase 1 gene (COI) of Splendidofilaria to decrease processing times and increase sensitivity as well as provide baseline data on the diversity of filariid infections in galliform species in Alaska. We screened a combined total of 708 galliform samples (678 unique individual birds) from different tissues (blood, muscle, and lung) for the presence of filarial DNA across the state of Alaska. Real-time PCR screening revealed an overall prevalence of filarial infection of 9.5% across species: Bonasa umbellus (0%, n = 23), Dendragapus fuliginosus (0%, n = 8), Falcipennis canadensis (26.8%, n = 198), Lagopus lagopus (2.6%, n = 274), Lagopus leucura (0%, n = 23), Lagopus muta (3%, n = 166), and Tympanuchus phasianellus (12.5%, n = 16). We observed microfilarial infections throughout most of Alaska except in Arctic regions and the Aleutian Islands where viable vectors may not be present.

Parasitic nematodes infect a variety of organisms including insects and vertebrates. To survive, they evade host immune responses to cause morbidity and mortality. Despite the vast clinical knowledge regarding nematode infections and their biological makeup, molecular understanding of the interactions between host and parasite remains poorly understood. The utilization of model systems has thus been employed to help elucidate the molecular interactions of the host immune response during parasitic nematode infection. Using model systems, it has been well established that parasitic nematodes evade host immunity by releasing excretory/secretory proteins (ESPs), which are involved in immunomodulation. Model systems have enabled researchers to characterize further the underlying mechanisms ESPs use to facilitate evasion and modulation of the host immune response. This review assessed notable ESPs from parasitic nematodes that infect vertebrates or insects and have been studied in mechanistic detail. Being able to characterize how ESPs affect the immune systems of hosts on a molecular level increases our understanding of host–parasite interactions and could lead to the identification of novel therapeutic targets and important molecular pathways.

The genus Eustrongylides includes zoonotic nematodes that infect fish species and fish-eating birds of freshwater ecosystems. This study aimed to evaluate the occurrence of Eustrongylides in the paratenic host Perca fluviatilis (European perch) and in the definitive host, Phalacrocorax carbo sinensis (great cormorant), in Lake Annone, a shallow eutrophic lake located in the pre-mountainous area of the Alps in northwest Italy where wintering cormorants coexist with new breeding colonies. A total of 114 European perch and 48 cormorants were examined for the occurrence of Eustrongylides. All parasites collected were identified with microscopic examination and molecular analysis. Overall, 11 specimens of European perch (9.6%) and 13 individuals of cormorants (27%) harbored nematodes identified as fourth-stage larvae and adults of Eustrongylides excisus. The observed prevalence of Eustrongylides spp. appears to be intermediate between the higher values in cormorant breeding areas in northern Europe and the lower prevalence observed in their wintering sites in southernmost Europe. Considering the eutrophication status of freshwater ecosystems and the increasing population of the cormorants, Eustrongylides has an increasing potential range of dispersion in Europe, including Italy; thus an extensive surveillance should be carried out, especially given the zoonotic potential of this nematode.

Advances in hybridization practices in U.S. catfish aquaculture have led to increased production of channel (Ictalurus punctatus) × blue catfish (Ictalurus furcatus) hybrids to capitalize on their more favorable production characteristics. However, the effects of typical channel catfish pathogens on hybrids are not well understood, including the digenean Bolbophorus damnificus, which has caused significant losses in channel catfish production. Three experiments were conducted to assess the longevity and site specificity of 2 life stages of B. damnificus impacting catfish production. The first experiment investigated the cercarial longevity and infectivity of B. damnificus over time. Channel catfish were individually challenged with 100 cercariae/fish with cercariae aged in 12-hr time intervals over 5 days (n = 5 fish/time point), with metacercarial cysts excised and enumerated 14 days postchallenge. There was a decrease in cercaria viability and encysted metacercariae over the first 36 hr, with the 12-hr time point having both the greatest cercaria survival and the highest number of metacercariae in exposed fish. The second experiment investigated the longevity of metacercariae within both channel and hybrid catfish. Fish (n = 30) were exposed to 2 treatments (75 or 150 cercariae/fish), and 2 fish from each treatment were sampled every 3 mo for 13 mo. Live metacercariae, based on motility observed after excystment, were found in both species up to 13 mo postchallenge, indicating the metacercariae of B. damnificus can persist throughout an entire growing season in both channel and hybrid catfish. The third experiment investigated the site specificity of metacercariae within both channel and hybrid catfish. Fish (n = 60/species) were challenged with 300 cercariae/fish and 9 fish/species were sampled after 90 days. Metacercariae were excised and enumerated from the anterior midsection (head and body), posterior midsection (trunk/caudal peduncle), ventral (belly), and caudal fin (tail) sections of each fish. Overall, the trunk/caudal peduncle had a 2-fold increase in the number of metacercariae excised, and although not significantly higher, results indicate this region should be the focal point of pondside assessment for the presence of B. damnificus because of ease of detection of encysted metacercariae.