This document represents a summary of parasites, in the broadest sense of the term, reported from Peromyscus maniculatus from throughout its range in North America. The document provides data from work ranging from paleontological findings to relatively current reports of parasites and parasitism from P. maniculatus and covers viruses, bacteria sensu lato, protists, helminths, and ectoparasites.

Understanding the factors shaping the niche of parasites and its expression over geographical space and through time continues to be a modern scientific challenge with the results of research in this area directly influencing both theoretical and applied biology. This is especially important for proactive management of zoonotic parasites such as Echinococcus multilocularis, the etiologic agent of alveolar echinococcosis. Echinococcus multilocularis has a Holarctic distribution; with its geographic range and prevalence increasing recently in areas of the western Palearctic, while its distribution dynamics are poorly understood in the Nearctic. In this paper, we use an ecological niche modeling (ENM) approach to: i) estimate the current spatial distribution of suitable conditions for the parasite in the Nearctic. ii) Evaluate the abiotic and biotic factors influencing the species distribution. iii) Assess the potential impact of climatic change on the distribution of this species in the Nearctic. Additionally, we report two new occurrence records of this parasite that significantly expands its known geographic range. We reviewed the occurrence records of E. multilocularis for the Nearctic. This was complemented by two new records of the species from Maryland and New Mexico identified using morphology and multivariate morphometrics of the rostellar hooks. From these data we created two ENMs using the software Maxent. The first ENM included climatic variables, while the second included the same abiotic data plus biotic information consisting of four host community-related data sets. We evaluated model performance and variable importance to explore the relation of these variables to the parasite niche. Finally, we projected the resulting niche model onto future climate change scenarios. We found that an important portion of the Nearctic has suitable conditions for E. multilocularis with adequate habitat in the West and East of the continent where the parasite has not been detected. We also found that the proposed biotic variables improve the model performance and provide unique information, while the most critical abiotic variable was related to the amount of solar radiation. Finally, under the future emission scenarios explored, the distribution of suitable habitat for the parasite is predicted to increase by 56 % to 76 %. We obtained a robust model that provides detail on the distribution of suitable areas for E. multilocularis, including areas that have not been explored for the presence of the parasite. The host community variables included in this study seem a promising way to include biotic data for ecological parasite niche modeling.

George Stewart died unexpectedly in a Florida hospital on 12 October 2017, of an undiagnosed cause after being admitted 10 days earlier. A communication from his wife, Breck, noted that 12 October also marked George’s and her 50th wedding anniversary. Breck was George’s constant companion and ardent supporter of his career endeavors. In memory of George, Gil Castro and John Ubelaker pay tribute to a friend and fellow parasitologist, providing a glimpse of his academic achievements and of him as an individual. This homage also conveys the personal responsibility he took and the effort he put forth to achieve his goals. George had an inclusive academic career and enjoyed a reputation as a noble and industrious individual and scientist. He was known for carving out and providing leadership in his parasitological niche. George obtained rigorous training in preparation for a career in parasitology. He was awarded a Bachelor of Science degree in 1969 from Tulane University and, in 1973, a doctorate degree from Rice University, two bastions of parasitology at the time George was preparing for his vocation. After receiving his doctorate degree, George remained at Rice in the capacity of postdoctoral fellow, research associate, and lecturer until 1976. Gil met George in 1972 soon after taking a position at the University of Texas Medical School at Houston. Gil went to the Biology Department at Rice to visit Clark Read and acquire some of his infected Tribolium flour beetles to be used to start experiments on adult Hymenolepis diminuta. As one would anticipate, meeting with Clark Read to discuss experiments was a pleasure. But adding to this was Gil meeting George Stewart in Read’s laboratory, where they chatted for some time. That fortuitous meeting began a friendship that involved interactions DOI: 10.1645/18-28 J. Parasitol., 104(3), 2018, pp. 342–344 American Society of Parasitologists 2018

Kalicephalus subulatus Molin, 1861, collected in Nicaragua and Chiapas, Mexico, from Constrictor constrictor imperator is reported and observations made on the morphology and reproduction in this nematode.

Metazoan gastrointestinal endoparasites were recovered from 10 of 14 (71.4%) gray foxes [Urocyon cinereoargenteus (Schreber, 1775)] collected in New Mexico from 1996 -1998. They include a pentastome Porocephalus sp., (n=1, 7.1%), a trematode: Fasciola hepatica Linnaeus, 1758 (n=1, 7.1%), the nematodes: Physaloptera rara Hall and Wigdor, 1918 (n=3, 14.3%), Physaloptera praeputialis Linstow, 1899 (n=2, 14.3%), an unidentified female Physaloptera sp. (n=1, 7.1%), Toxocara mystax (Zeder, 1800) (n=2, 14.3%), Toxocara canis (Werner, 1782) (n=1, 7.1%), Spirocerca lupi (Rudolphi, 1809) (n=6, 42.9%), and cestodes: Taenia pisiformis (Bloch, 1780) n=3, n=3, (21.4%), Taenia serialis (Gervais, 1847) (n=3, 21.4%), and Mesocestoides kirbyi Chandler, 1944 (n=7, 50%). All parasites found are new records for the gray fox in New Mexico. The parasites, Porocephalus sp, Fasciola hepatica, Toxocara mystax and Mesocestoides kirbyi are new records for the gray fox for North America.

Four nematodes Physaloptera rara (11/31, 35.5%), Physaloptera (5/31, 16.0%), Toxascaris leonina (1/31, 3.2%), and Toxocara canis (17/31, 54.8%) and two cestodes Dipylidium caninum (11/31, 35.5%) and Mesocestoides variabilis (9/31, 29.0%) were recovered from 23 of 31 (74%) swift foxes, Vulpes velox, for the first time from New Mexico.

At Southern Methodist University campus about 6 miles south of Taos, New Mexico,, we recovered tetrathyridia of Mesocestoides in five Peromyscus maniculatus in the summers of 2008 (3 of 129, 0.023%), 2009 (0 of 98, 0%), 2010 (1 of 112, 0.008%), 2011 (0 of 88, 0%), and 2012 (1 of 86, 0.011%). Tetrathyridia from the body cavity of one of the five infected mice were injected into the peritoneal cavity of laboratory white mice, Mus musculus. Our later examination of the laboratory mice revealed heavy infections of tetrathyridia continuing to reproduce asexually. Here we provide important new information on the prevalence of asexuality among tetrathyridia and underscore the need for further study of this variation among metacestodes of this cosmopolitan genus.

One cestode, Mesocestoides variabilis (2/8, 25%), and two nematodes, Ancylostoma caninum (1/8, 12.5%) and Spirocerca lupi (1/8, 12.5%), are recorded from three of eight (37.5%) red foxes Vulpes vulpes for the first time from New Mexico. All helminths have been found previously in red foxes.

Akodonema luzsarmientae n.g., n.sp. (Nemata: Metastrongyloidea) is described from the pulmonary arteries and heart from several individuals of "soft grass mouse," Akodon mollis (Rodentia: Cricetidae), collected in the region of Ancash, Peru. The new genus and species is distinguished by a reduction of the dorsal ray to 2 small widely separated papillae.

Pharyngodon kirbii sp. n. and P. mudgi sp. n. are described from Cnemidophorus scalaris and Coleonyx brevis from West Texas. The former species is unique in that the males possess two pairs of sessile papillae on the genital cone; the latter species can be distinguished from other species in which females possess a spinous tail by the anterior location of the vulva in the female and the reduced length of the tail in the male. The occurrences of P. cnemidophori in Cnemidophonts tigris and P. warneri in Cnemidophorus inornatus represent new host and distribution records. P. paratectipcnis is transferred to the genus Spauligodon. Skrjabinodon medinae is proposed as a new combination for P. medinae. A key is provided for species of the genus Phan/ngodon. During a survey of the helminths of reptiles from West Texas several species of lizards were found to be infected with two undescribed and two previously described species of the genus Pharyngodon Diesing, 1861. The genus Pharyngodon, as presently under- stood, contains 20 species, three of which are known only from females, P. batrachiensis Walton, 1929, P. boulengerula Ubelaker, 1965, and P. polypcdatis Yamaguti, 1941. Since Pharyngodon has been divided into several genera based on characters of the males— Spauligodon Skrjabin, Sehikhobalova, and La- godovskaja, 1960; Skrjabinodon Inglis, 1968; and the closely related genus Parathelandros Baylis, 1930, as redefined by Inglis, 1968—it is only for convenience that the species P. batrachiensis, P. boulengerula, and P. polij- pedatis are retained in the genus Pharyngodon. The worms were fixed in alcohol and cleared in lactophenol or glycerine for study. All measurements are in microns unless otherwise noted. The range is followed by the average in parentheses.

Seventy-eight spotted ground squirrels, Xerospermophilus (syn. Spermophilus) spilosoma, from 2 different habitats (grassland and creosote bush) located in central New Mexico, were examined for helminth parasites. Eighteen hosts were negative and from 60 hosts the following helminth parasites were recovered: Acanthocephala: Moniliformis clarki; Nematoda: Citellina triradiata, Dermatoxys veligera, Heteromyoxyuris deserti, Mastophorus dipodomis, Physaloptera massino, Protospirura ascaroidea, Pterygodermatites coloradensis, Subulura novomexicanus, Syphacia eutamii, and Syphacia peromysci; Cestoda: Hymenolepis citelli. The parasites D. veligera, Heteromyoxyuris deserti, Mastophorus dipodomis, Moniliformis clarki, Protospirura ascaroidea, and S. peromysci are recorded for the first time from this host.

A description is presented of a new species of Subulura Molin, 1860, Subulura novomexicanus, collected from the spotted ground squirrel, Spermophilus spilosoma Bennett, 1833, in New Mexico. The males are 24 to 29 mm long, precloacal sucker 1.7-2.0 mm from posterior end, spicules subequal 0.83-1.0 long, and gubernaculum Y-shaped 0.21-0.39 mm long. Females are 34-39 mm long, vulva near middle of body 14.06-22.00 mm from anterior end, and eggs 0.04-0.05 mm long by 0.03-0.04 mm wide. The new species is distinguished from Subulura ungulatus Erickson, 1938 in being longer and having spicules that are distinctively different in size and form. It also differs from Subulura nevadense Babero, 1973 in being longer and having a larger egg size and smaller spicules. The new species is most similar to Subulura andersoni (Cobbold, 1876) (Thwaite, 1927); however, the males of this species are smaller and they have broad cervical alae, and the adults occur in squirrels of India. Reexamination of S. ungulatus showed I I pairs of caudal papillae, including 4 pairs of preanals, I pair adanal and lateral, and 6 pairs of postanal papillae located at the end of the tail. Spermophilus richardsoni (Sabine, 1822) is a new host record for S. nevadense, and Montana is a new distributional record for this nematode. Eimeria callospermophili Henry, 1932, is a new record for S. spilosoma.

A widely utilized rabbit corneal cell line, SIRC, was characterized ultrastructurally and immunohistologically. Although SIRC cells are often described as being of epithelial origin, important ultrastructural and antigenic characteristics indicate that these cells are fibroblastic and not epithelial. SIRC cells lack desmosomes, cytoplasmic filaments, and cytokeratin-structures that are characteristic of corneal epithelial cells. By contrast, the dendritic morphology, presence of vimentin, and the extensive dense accumulations of ribosomes and rough endoplasmic reticulum are consistent with a fibroblastic phenotype. Collectively, the morphology, ultrastructural features, and antigenic composition favor the hypothesis that SIRC cells are fibroblastic cells (keratocytes) and not corneal epithelial cells.

A study of the ultrastructure of the epidermis of Syndisyrinx sp. from the sea urchin Lytechinus variegatus in Jamaican waters reveals several cell types. The anterodorsal surface contains squamous cells, and some basally located cells, at least partially overlapped by the cytoplasm of other cells, within a simple epithelial layer. The squamous and low columnar cells are sparsely ciliated. The pharyngeal epithelium contains simple, tall columnar, highly ciliated cells that border a special type of pharyngeal cell modified for movement of the pharynx. The anteroventral epidermis contains tall, columnar, highly ciliated cells. The epidermis of the dorsomedian, dorsoposterior, ventromedian, and ventroposterior regions contains cells similar to those described within the more anteriorly located epidermis, except for occasional structural modifications which probably reflect the stage of activity of the cell. Both dorsal and ventral surfaces contain light and dark cells. Modified cilia, with a conspicuous expansion of cytoplasm surrounding the shaft just above the surface of the cells, and polymorphic microvilli are described.