Journal of Parasitology最新文献

{"title":"REDESCRIPTION OF PARABENEDENIELLA POSTEROCOLPA (HARGIS, 1955) BRULE AND BULLARD N. GEN. ET N. COMB. (MONOGENOIDEA: CAPSALIDAE: ENTOBDELLINAE) FROM INFECTIONS ON THREE BATOID HOSTS (RHINOPTERIDAE AND MOBULIDAE) WITH PHYLOGENETIC ANALYSIS AND COMMENTS ABOUT CAPSALID HOST SPECIFICITY.","authors":"John H Brule, Micah B Warren, Stephen A Bullard","doi":"10.1645/25-92","DOIUrl":"10.1645/25-92","url":null,"abstract":"<p><p>We herein propose Parabenedeniella Brule and Bullard n. gen. to accommodate Parabenedeniella posterocolpa n. comb., formerly of Benedeniella Johnston, 1929 (both Capsalidae: Entobdellinae). Parabenedeniella differs from all other entobdelline genera by the combination of having a U-shaped (not looped) proximal portion of the cirrus sac, a vagina that is directed posterolaterad, a tube-like proximal portion of the vagina that is approximately one-third of the total length of the vagina, a thick-walled and muscular distal portion of the vagina that is approximately two-thirds of the total length of the vagina, and a dorsal vaginal pore that is submarginal to the sinistral body margin posterior to or at the level of the testes. We collected specimens of P. posterocolpa from 5 cownose rays, Rhinoptera bonasus (Rhinopteridae), and 1 Brazilian cownose ray, Rhinoptera brasiliensis, from the Gulf of America and from 1 giant manta, Mobula birostris (Mobulidae), from an exhibit tank at a public aquarium, which also contained cownose rays. Parasite specimens were fixed in 10% neutral buffered formalin for morphology or preserved in 95% EtOH for DNA extraction. All of the collected specimens of P. posterocolpa were morphologically indistinguishable from the holotype of P. posterocolpa and were diagnosed by having anterior attachment organs, each with anteroventral grooves and a dorsal papilla, and a dorsal vaginal pore located level with or posterior to the testes. We generated 15 sequences: the ITS1, 28S, and COI from 2 specimens of P. posterocolpa from a cownose ray and 2 specimens from a giant manta plus a specimen from the Brazilian cownose ray. The only extant 28S sequence previously ascribed to P. posterocolpa was identical to each of our 28S sequences (no previous ITS1 or COI sequences for P. posterocolpa exist), and the new ITS1 sequences were identical. Two morphologically identical specimens of P. posterocolpa spaced approximately 5 mm apart on a single host specimen had distinct COI sequences (2 bp or 0.2% difference). The 28S analysis recovered P. posterocolpa as a sister to a clade comprising species of Entobdella and Neoentobdella (all Entobdellinae). The 28S and COI phylogenetic analyses recovered Entobdellinae as sister to Capsalinae; both were recovered as sister to Dionchinae (both Capsalidae). This is the first study of P. posterocolpa that combines morphology and nucleotide sequences from multiple infections and host species, the first record of P. posterocolpa infecting the Brazilian cownose ray, and the first detailed taxonomic description of specimens of P. posterocolpa infecting the giant manta.</p>","PeriodicalId":16659,"journal":{"name":"Journal of Parasitology","volume":"112 3","pages":"368-388"},"PeriodicalIF":1.2,"publicationDate":"2026-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148330534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"TISSUE-SPECIFIC ORIGIN OF EGGS IN THE DEFINITIVE HOST DRIVES TRANSCRIPTOMIC AND BEHAVIORAL DIFFERENCES IN SCHISTOSOMA MANSONI MIRACIDIA.","authors":"Sophie Willett, Sonja A Olson, Rachel V Horejsi, Chase N Nelson, Nicolas J Wheeler","doi":"10.1645/25-69","DOIUrl":"10.1645/25-69","url":null,"abstract":"<p><p>Schistosomiasis is a neglected tropical disease caused by human-infective schistosomes (Trematoda: Schistosoma). Intestinal schistosomiasis in sub-Saharan Africa and the Neotropics is caused primarily by Schistosoma mansoni and is transmitted by several Biomphalaria planorbid snail species. Adult male and female parasites in the definitive mammalian host pair and reside in the mesenteric vasculature; females lay eggs that traverse the intestinal wall to be excreted, but a significant proportion become trapped in host tissues, especially the liver, eliciting granulomatous immune responses that underlie most disease pathology. Schistosoma mansoni is the primary lab model for research, and, due to the abundance and ease of harvesting, liver-derived eggs are almost exclusively used to maintain the life cycle and to study miracidia and subsequent larval stages. However, recent evidence shows that eggs from the liver or intestine have key morphometric, transcriptomic, and antigenic differences, which can profoundly affect experimental outcomes. To determine whether these differences extend to the miracidia stage, we compared miracidia hatched from mouse liver and intestine-derived eggs, sequencing their transcriptomes and assessing their unstimulated behaviors over time in an arena allowing for high-resolution tracking of miracidia behavior at a large spatiotemporal scale. We found that while transcriptomic profiles of miracidia are distinguishable based on egg tissue origin, only a small subset of genes is differentially expressed. Further, the basic, unstimulated behavior of miracidia that developed in different niches of the definitive host was significantly different. These different behavioral programs may reflect intrinsic developmental programming or differential viability and hardiness related to tissue origin. These findings underscore the importance of egg source in experimental design and interpretation, with significant implications for the maintenance of laboratory life cycles and the use of miracidia in schistosomiasis research.</p>","PeriodicalId":16659,"journal":{"name":"Journal of Parasitology","volume":"112 3","pages":"360-367"},"PeriodicalIF":1.2,"publicationDate":"2026-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13389970/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148308607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DESCRIPTION, REDESCRIPTION, AND LIFE CYCLES OF PARORCHIS LAFFERTYI N. SP. AND PARORCHIS CATOPTROPHORI (TREMATODA: DIGENEA: PHILOPHTHALMIDAE) FROM THE CALIFORNIA HORN SNAIL, CERITHIDEOPSIS CALIFORNICA (GASTROPODA: POTAMIDIDAE).","authors":"Alexandria P Nelson, Daniel C G Metz, Ryan F Hechinger","doi":"10.1645/24-42","DOIUrl":"10.1645/24-42","url":null,"abstract":"<p><p>We describe Parorchis laffertyi n. sp., a trematode infecting the California horn snail, Cerithideopsis californica (Haldeman, 1840), as a first intermediate host. The first intermediate host stages of this species were previously cryptic with Parorchis catoptrophori Dronen & Blend, 2008, which also infects C. californica. For both species, we describe the parthenita colonies, soldier rediae, reproductive rediae, cercariae, metacercariae, and sexual adults by using DNA sequencing and material from natural and experimental infections. Our study of all life stages was conducted with material originating from naturally infected, lab-maintained horn snails from San Diego, California. Cercariae that were repeatedly shed from specific, labeled snails were used as material for experimental infections, developmental studies, and DNA sequencing. In all cases, data were tracked to their source individual first intermediate host colonies. These same colonies were dissected to describe the morphology, behavior, and demographics of reproductive and soldier rediae. Metacercaria descriptions came from cercariae shed and encysted in the laboratory; we also document a metacercaria developmental time series. We experimentally exposed final host chickens (Gallus gallus domesticus Linnaeus, 1758) and ducks (Anas platyrhynchos domesticus Linnaeus, 1758) to metacercariae per cloaca and successfully obtained and described the sexual adults of P. catoptrophori and an immature adult of P. laffertyi from the chickens. Both cytochrome c oxidase subunit I (COI) and 28S rDNA phylogenetic analyses supported the hypothesis that P. catoptrophori and P. laffertyi are 2 species of Parorchis Nicoll, 1907. As indicated in its original description, adults of P. catoptrophori can be readily distinguished from adults of other Parorchis species by their possession of a greater number of collar spines (∼80 vs. ∼60 in most other species); a bipartite pharynx; a pharynx to oral sucker ratio of ∼1:2; presence of esophageal diverticula; and deeply lobed testes. The immature adult of P. laffertyi can be distinguished from adults of other Parorchis species by the collar spine number (∼55); bipartite pharynx; a pharynx to oral sucker ratio of ∼1:2; presence of esophageal diverticula; and distinct COI and 28S sequence data. Mature adult specimens of P. laffertyi are needed to parse additional morphological characteristics. We used our morphometric data and additional published information to provide an emended diagnosis for the genus Parorchis. There are now 18 formally named Parorchis species, 4 of which have had their first intermediate host stages described and 4 of which have available DNA sequence information.</p>","PeriodicalId":16659,"journal":{"name":"Journal of Parasitology","volume":"112 3","pages":"319-342"},"PeriodicalIF":1.1,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148143656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CONFIRMATION OF SARCOCYSTIS INFECTIONS IN TONGUES OF FLORIDA PANTHERS (PUMA CONCOLOR CORYI).","authors":"J P Dubey, Aditya Gupta, Mason V Reichard, Marc Criffield, Bambi C F Clemons, B M Rosenthal","doi":"10.1645/26-14","DOIUrl":"10.1645/26-14","url":null,"abstract":"<p><p>This study reports the prevalence, morphological, and molecular identification of Sarcocystis species in the tongues of Florida panthers (Puma concolor coryi). By light microscopy, sarcocysts were found in 46 of 108 (42.6%) panthers and appeared to represent at least 2 morphological types. One morphological type had serrations on the sarcocyst wall and resembled Sarcocystis felis reported from domestic and wild felids; molecular characterization using the ITS1 gene confirmed its identity. The second kind of sarcocyst had a smooth sarcocyst wall without any visible protrusions. The possibility of other unidentified Sarcocystis species is discussed.</p>","PeriodicalId":16659,"journal":{"name":"Journal of Parasitology","volume":"112 3","pages":"305-312"},"PeriodicalIF":1.2,"publicationDate":"2026-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147988007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MOLECULAR CHARACTERIZATION OF SARCOCYSTIS SPOROCYSTS IN INTESTINES OF BOBCAT (LYNX RUFUS) FROM MINNESOTA.","authors":"Aditya Gupta, Carolin Humpal, Michelle Carstensen, B M Rosenthal, J P Dubey","doi":"10.1645/26-15","DOIUrl":"10.1645/26-15","url":null,"abstract":"<p><p>Sarcocystis species are heteroxenous protozoan parasites of major veterinary and public health relevance, yet the role of wild felids in their natural transmission cycles remains poorly understood. In this study, we investigated Sarcocystis infections in 189 bobcats (Lynx rufus) harvested from Minnesota during 2024-2025. Intestinal homogenates of 179 were examined microscopically, and Sarcocystis sporocysts were found in 38 bobcats (21.2%). DNA was extracted from all 38 positive samples, of which 19 were PCR-positive, and 14 yielded high-quality sequences for molecular characterization using partial 18S rRNA, 28S rRNA, and mitochondrial COI markers. Molecular results confirmed the presence of Sarcocystis bovifelis and Sarcocystis svanai-like. Due to inconsistent amplification and partial overlap among nuclear markers, only COI was suitable for phylogenetic analysis. The COI-based phylogenetic tree resolved strongly supported clades corresponding to these species (bootstrap 99-100%). These findings provide strong molecular evidence that bobcats in Minnesota serve as natural definitive hosts for S. bovifelis and S. svanai-like.</p>","PeriodicalId":16659,"journal":{"name":"Journal of Parasitology","volume":"112 3","pages":"313-318"},"PeriodicalIF":1.2,"publicationDate":"2026-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147987986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"EFFECTS OF AVIAN MALARIA IN A POPULATION OF CERULEAN WARBLER (SETOPHAGA CERULEA) WITH FIRST DOCUMENTATION OF HAEMOSPORIDIAN LINEAGES INFECTING THE SPECIES.","authors":"Julian B Grudens, Kamal Islam","doi":"10.1645/24-88","DOIUrl":"10.1645/24-88","url":null,"abstract":"<p><p>Avian haemosporidians (Haemosporida) commonly infect terrestrial birds worldwide and can have negative consequences for individuals. We studied avian haemosporidian infections and mitochondrial cytochrome-b lineages in a southern Indiana breeding population of cerulean warbler (Setophaga cerulea; n = 51) over 2 yr with traditional microscopy and standard molecular methods. We investigated potential effects of infection on individual body condition, associations of host specificity and levels of infection (parasitemia) according to haemosporidian lineage genus, and geographic distributions of lineages. Additionally, we aimed to provide the first documentation of haemosporidian lineages for the species and to estimate population prevalence and parasitemia for comparison with earlier studies of the species. Parasitemia was low (<1% of cells infected) for most individuals, indicative of chronic infections, and we did not find any negative effects of infection on body condition of males (n = 49); however, mean body condition of individuals with Plasmodium sp. infections was higher than that of uninfected individuals, which could reflect survivorship bias in the sample. Neither host specificity nor parasitemia varied by haemosporidian genus, and for some lineages, we inferred likely geographic regions of transmission to Neotropical-Nearctic migrants, including the cerulean warbler. Prevalence was moderate at 31.4% across both years, and we documented 11 unique lineages in the genera Haemoproteus and Plasmodium, 2 of which were novel. These findings advance knowledge of host-parasite interactions for a declining avian species and add to the broader field of avian haemosporidian biology, including novel host-parasite associations.</p>","PeriodicalId":16659,"journal":{"name":"Journal of Parasitology","volume":"112 3","pages":"292-304"},"PeriodicalIF":1.2,"publicationDate":"2026-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147941811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"FIRST DETECTION OF ENTEROMYXUM LEEI FROM CREOLE WRASSE BODIANUS PARRAE (BLOCH & SCHNEIDER, 1801) WITH EXPANDED MORPHOLOGICAL AND MOLECULAR CHARACTERIZATION OF THE PARASITE.","authors":"Ethan T Woodyard, Justin M Stilwell, Sean M Perry, Alexa J Delaune, Natalie K Stilwell, T Graham Rosser, Jonah A Nguyen, Matt J Griffin","doi":"10.1645/24-18","DOIUrl":"10.1645/24-18","url":null,"abstract":"<p><p>In June of 2022, 3 creole wrasses, Bodianus parrae, from a public display aquarium were submitted for diagnostic examination at Mississippi State University's College of Veterinary Medicine. Fresh myxospores recovered from the intestines were morphologically consistent with previous accounts of Enteromyxum leei (Diamant, Lom & Dyková, 1994). Molecularly, myxospores from the present study were 99.7-100% and 99.7-99.8% similar to publicly available E. leei sequences at 18S small subunit ribosomal (18S) and 28S large subunit ribosomal (28S) genes, respectively. Internal transcribed spacer region 1 (ITS1), 5.8S ribosomal rRNA gene (5.8S), and internal transcribed spacer region 2 (ITS2) sequences were 95.8-98.0%, 100%, and 99.9% similar, respectively, to the only publicly available data from these regions from E. leei. Eukaryotic elongation factor 2 (EEF2) sequences were 98.8% similar to the available EEF2 sequence of E. leei in GenBank. Lastly, cytochrome c oxidase subunit 1 (COI) sequences were 98.6% similar to previously published data. Bayesian phylogenetic analyses using both single locus 18S sequence data, concatenated 18S, 28S, and EEF2 data, and concatenated 18S, 28S, and COI amino acid sequences from each of the 3 wrasses grouped E. leei from the present study with previously published E. leei sequences with high Bayesian and maximum likelihood support. This is the first account of E. leei from B. parrae. Histological assessment reveals pathological changes to intestinal epithelia consistent with previous accounts of E. leei, with 18S, ITS1, 5.8S, ITS2, 28S, EEF2, and COI sequence data providing greater phylogenetic resolution of this enigmatic species. These morphological and molecular data from an enteromyxosis outbreak in a mixed-species exhibit at a public aquarium offer robust species-level identification of the causative agent, E. leei.</p>","PeriodicalId":16659,"journal":{"name":"Journal of Parasitology","volume":"112 3","pages":"277-291"},"PeriodicalIF":1.2,"publicationDate":"2026-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147930663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"HELMINTH PARASITE COMMUNITY OF THE LIZARD GONATODES HUMERALIS (SQUAMATA: SPHAERODACTYLIDAE) IN THE AMAZON: STRUCTURE AND COMPARATIVE ANALYSIS BETWEEN TWO DIFFERENT AREAS.","authors":"Amanda L M Rosa, Saturno Dias, Fabiano Paschoal, Felipe B Pereira","doi":"10.1645/25-70","DOIUrl":"10.1645/25-70","url":null,"abstract":"<p><p>Gonatodes humeralis is a small gecko common in the Amazon, and little is known about its parasite community. The present work assessed for the first time in detail the parasite community of G. humeralis in 2 conservation areas of the municipality of São Luís, State of Maranhão, Brazil, and the factors associated with it. A total of 132 lizards were collected. We found only 3 parasite taxa: the nematode Skrjabinelazia galliardi in the stomach, the digenean Mesocoelium sp., and the cestode Oochoristica sp., both in the small intestine. Skrjabinelazia galliardi was the most dominant, prevalent, and abundant, followed by Oochoristica sp.; Mesocoelium sp. was rare, infecting only 2 female lizards from one of the collection sites. The parasite community was depauperate, noninteractive, and parasites were highly aggregated, which is typical of lizard hosts. Host body length was a strong factor shaping the parasite community, whereas sex, ontogeny, and collection site exerted a weak influence on it. Because all parasites are trophically transmitted, the host diet is likely an important indicator of parasite transmission in the present community. The local anthropic activities possibly influence the environmental quality, which may impact the existence of intermediate hosts for Mesocoelium sp. and its transmission. Gonatodes humeralis harbored only adult parasites, indicating that this species does not play a significant role as intermediate/paratenic host in the area but represents an important definitive host at least for S. galliardi and Oochoristica sp.</p>","PeriodicalId":16659,"journal":{"name":"Journal of Parasitology","volume":"112 3","pages":"268-276"},"PeriodicalIF":1.2,"publicationDate":"2026-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147856597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"AN AUTOMATED CHEMILUMINESCENCE IMMUNOASSAY FOR DETECTION OF GIARDIA DUODENALIS ANTIGENS FROM CANINE SPECIMENS.","authors":"Xiaolin Li, Kenneth A Browne, Caixia Dong, Ziye Liu","doi":"10.1645/25-101","DOIUrl":"10.1645/25-101","url":null,"abstract":"<p><p>This study reports the automation and evaluation of the Giardia chemiluminescence assay (GCA), an assay designed to detect infectious Giardia duodenalis present in veterinary stool samples. The automated GCA (auto-GCA) enabled stringent step pacing and significant reduction of hands-on time for the assay operator, and it yielded assay performance comparable with the manual assay in activity profiles, dose-dependent ranges and half-maximal effective concentrations. In a study with clinic-collected canine stool specimens, 115 samples analyzed by auto-GCA had a sensitivity of 95.1% and a specificity of 90.7% compared with a standard G. duodenalis ELISA. In another study, 81% of 62 canine samples that were identified as borderline by ELISA were classified definitively as positive or negative for G. duodenalis by auto-GCA. To our best knowledge, the auto-GCA is the first system in the parasite diagnosis area to use full automation and chemiluminescence, and it is expected to improve work quality for individual researchers and for laboratories.</p>","PeriodicalId":16659,"journal":{"name":"Journal of Parasitology","volume":"112 3","pages":"261-267"},"PeriodicalIF":1.2,"publicationDate":"2026-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147856554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MUSEUM SPECIMENS OF WESTERN DIAMOND-BACKED RATTLESNAKES (VIPERIDAE: CROTALUS ATROX) REVEAL TRENDS IN BODY SIZE, DIET, AND ENDOPARASITES OVER THE LAST 75 YEARS.","authors":"Irvin Arroyo-Torres, Sara V Brant, J Tomasz Giermakowski, Samantha Armijo, Lisa N Barrow","doi":"10.1645/24-85","DOIUrl":"10.1645/24-85","url":null,"abstract":"<p><p>Climate projections for the Southwestern United States predict increases in temperature, drought intensity and frequency, and wildfire intensity and frequency. Such climatic change is expected to impact communities and species of the region, including Crotalus atrox (western diamond-backed rattlesnake) and its helminth communities. We hypothesized that C. atrox in New Mexico has experienced measurable changes in body size, diet composition, and helminth communities over the past century. We examined specimens of C. atrox from 3 time periods: 1947-1960 (1950s, n = 34), 1980-1990 (1980s, n = 53), and 2011-2021 (2010s, n = 57). We dissected specimens of C. atrox and recorded snout-vent length (SVL), sex, age class (juvenile or adult), prey items from gastrointestinal (GI) contents, and helminth prevalence. We then tested for differences in body size, diet, and helminth prevalence between sexes of C. atrox and across time periods. To better understand the environmental breadth of the helminths in C. atrox, we also performed a literature search to reconstruct in what coarse-scale habitat conditions the helminths identified in our study have previously been reported. Over the 3 time periods we studied, body size and diet composition have remained stable; however, helminth community composition appears to have shifted significantly. Kalicephalus inermis, Mesocestoides sp., and a nematode in the family Pharyngodonidae were recovered from snakes from the 1950s, followed by Hexametra boddaertii, Mesocestoides sp. and Oochoristica osheroffi from the 1980s. Finally, only O. osheroffi was recovered from snakes from the 2010s. We also found that O. osheroffi appears to tolerate areas that often lack reliable moisture levels. We suggest 3 hypotheses explaining the observed shift in helminth community composition: changes to climate, undetected changes in the diet of C. atrox, or other untested factors. Museum vouchers of both the hosts and the helminths recovered herein are available for verification, additional analyses or in-depth species reevaluations.</p>","PeriodicalId":16659,"journal":{"name":"Journal of Parasitology","volume":"112 3","pages":"250-260"},"PeriodicalIF":1.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147816671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}