Diversity of Trichobilharzia in New Zealand with a new species and a redescription, and their likely contribution to cercarial dermatitis.

In response to annual outbreaks of human cercarial dermatitis (HCD) in Lake Wanaka, New Zealand, ducks and snails were collected and screened for avian schistosomes. During the survey from 2009 to 2017, four species of Trichobilharzia were recovered. Specimens were examined both morphologically and genetically. Trichobilharzia querquedulae, a species known from four continents, was found in the visceral veins of the duck Spatula rhynchotis but the snail host remains unknown. Cercaria longicauda [i.e. Trichobilharzia longicauda (Macfarlane, 1944) Davis, 2006], considered the major aetiological agent of HCD in Lake Wanaka, was discovered, and redescribed from adults in the visceral veins of the duck Aythya novaeseelandiae and cercariae from the snail Austropeplea tomentosa. Recovered from the nasal mucosa of Ay. novaeseelandiae is a new species of Trichobilharzia that was also found to cycle naturally through Au. tomentosa. Cercariae of a fourth species of Trichobilharzia were found in Au. tomentosa but the species remains unidentified.

First confirmed record of Trichobilharzia franki Müller & Kimmig, 1994, from Radix auricularia (Linnaeus, 1758) for Austria.

Avian schistosomes are of medical and veterinary importance as they are responsible for the annually occurring cercarial dermatitis outbreaks. For Austria, so far, only Trichobilharzia szidati Neuhaus 1952 was confirmed on species level as causative agent of cercarial dermatitis. Here we present the first record of Trichobilharzia franki Müller & Kimmig 1994 in Austria. The species was detected during a survey of digenean trematodes in Upper Austrian water bodies. Furthermore, we provide DNA barcodes of T. franki as well as measurements of several parasite individuals to indicate the intraspecific diversity. We also recommend the usage of an alternative primer pair, since the "standard COI primer pair" previously used for Schistosomatidae amplified an aberrant fragment in the sequence of T. franki. Overall, our study shows how limited our knowledge about occurrence and distribution of avian schistosomes in Austria is and how important it is to acquire such a knowledge to estimate ecological and epidemiological risks in the future.

Mefenoxam, Itraconazole, and Terbinafine Combination Therapy for Management of Pythiosis in Dogs (Six Cases).

Pythium insidiosum is an oomycete that encysts in the skin or gastrointestinal tract, leading to pythiosis. Pythiosis is reported in tropical and subtropical climates, affecting dogs and rarely cats. Surgical resection is the treatment of choice; however, cases present late in the disease and lesions are often nonresectable. Medical management is typically unsuccessful, with uncommon exceptions; however, mefenoxam, an agricultural fungicide, has in vitro efficacy against P insidiosum. We describe the use of mefenoxam, itraconazole, and terbinafine (MIT) in five dogs with gastrointestinal pythiosis and one dog with cutaneous pythiosis. Two of the gastrointestinal cases had disease extending to surgical margins and received MIT: resolution of clinical signs and seronegativity occurred after 189-193 days. Another case underwent surgical resection and MIT. The dog improved but subsequently developed a rectal mass, which responded to addition of prednisone and immunotherapy. Two cases were treated with MIT alone, and response varied. Efficacy of MIT in cutaneous pythiosis could not be determined. MIT may result in improved survival and seronegativity in dogs with incompletely resected gastrointestinal pythiosis. Mefenoxam is EPA registered, and extralabel use under the Animal Medicinal Drug Use Clarification Act does not apply. Additional research is recommended before use.

Quantitative proteomic profiling of immune responses to Ichthyophthirius multifiliis in common carp skin mucus.

Ichthyophthirius multifiliis, a ciliated protozoan parasite, causes ichthyophthiriasis and leads to considerable economic losses to the aquaculture industry. Understanding the fish immune response and host-parasite interactions could support developing novel strategies for better disease management and control. Fish skin mucus is the first line of defence against infections through the epidermis. Yet, the common carp, Cyprinus carpio, protein-based defence strategies against infection with I. multifiliis at this barrier remain elusive. The skin mucus proteome of common carp was investigated at 1 day and 9 days post-exposure with I. multifiliis. Using nano-LC ESI MS/MS and statistical analysis, the abundance of 19 immune related and signal transduction proteins was found to be differentially regulated in skin mucus of common carp in response to I. multifiliis. The analysis revealed increased abundance values of epithelial chloride channel protein, galactose-specific lectin nattection, high choriolytic enzyme 1 (nephrosin), lysozyme C, granulin and protein-glutamine gamma-glutamyltransferase 2 in I. multifiliis-exposed carp skin mucus. Multiple lectins and a diverse array of distinct serpins with protease inhibitor activity were identified likely implicated in lectin pathway activation and regulation of proteolysis, indicating that these proteins contribute to the carp innate immune system and the protective properties of skin mucus. The results obtained from this proteomic analysis enables a better understanding of fish host response to parasitic infection and gives insights into the key role skin mucus plays in protecting fish against deleterious effects of I. multifiliis.

Demodex canis regulates cholinergic system mediated immunosuppressive pathways in canine demodicosis.

Demodex canis infestation in dogs remains one of the main challenges in veterinary dermatology. The exact pathogenesis of canine demodicosis is unknown but an aberration in immune status is considered very significant. No studies have underpinned the nexus between induction of demodicosis and neural immunosuppressive pathways so far. We have evaluated the involvement of cholinergic pathways in association with cytokines regulation as an insight into the immuno-pathogenesis of canine demodicosis in the present study. Remarkable elevations in circulatory immunosuppressive cytokine interleukin-10 and cholinesterase activity were observed in dogs with demodicosis. Simultaneously, remarkable reduction in circulatory pro-inflammatory cytokine tumour necrosis factor-alpha level was observed in dogs with demodicosis. Findings of the present study evidently suggest that Demodex mites might be affecting the cholinergic pathways to induce immunosuppression in their host and then proliferate incessantly in skin microenvironment to cause demodicosis.

Parasitic outbreak of the copepod Balaenophilus manatorum in neonate loggerhead sea turtles (Caretta caretta) from a head-starting program.

BACKGROUND: Diseases associated to external parasitosis are scarcely reported in sea turtles. During the last decades several organism have been documented as a part of normal epibiont community connected to sea turtles. The copepod Balaenophilus manatorum has been cited as a part of epibiont fauna with some concern about its parasitic capacity. This study serves three purposes, i.e. (i) it sheds light on the type of life style that B. manatorum has developed with its hosts, particularly turtles; (ii) it makes a cautionary note of the potential health risks associated with B. manatorum in sea turtles under captivity conditions and in the wild, and (iii) it provides data on effective treatments against B. manatorum. RESULTS: We report for the first time a massive infestation of the copepod B. manatorum and subsequent acute mortality in a group of loggerhead sea turtle hatchlings. Four-month-old turtles from a head-starting program started exhibiting excitatory and fin rubbing behavior preceding an acute onset of lethargy, skin ulceration and death in some animals. All the individuals (n = 57) were affected by severe copepod load and presented different degrees of external macroscopic skin lesions. The ventral area of front flippers, axillar and pericloacal skin were mostly affected, and were the main parasite distribution regions. Copepods were also detected on plastron and carapace sutures. The gut contents of B. manatorum reacted positively for cytokeratin, indicating consumption of turtle skin. Severe ulcerative necrotic dermatitis and large amount of bacteria presence were the major histopathological findings. CONCLUSIONS: Individual fresh water immersion for 10 min and lufenuron administration (0.1 ppm) to the water system every 2 weeks proved effective for removing turtle parasites and to control re-infestation, respectively. The results from our study clearly indicated that B. manatorum individuals consume turtle skin. The pathological effects of this agent and the potential implications in sea turtle conservation and management are discussed.

Skin parasitism by Paratrichosoma recurvum in wild American crocodiles and its relation to environmental and biological factors.

Paratrichosma spp. are capillarid worms that parasitize the abdominal skin of crocodiles. They are likely not a threat to crocodiles' health, but they affect the skins' commercial value. No successful treatment exists against this parasite, and present knowledge of its life cycle is limited. Herein we report new information on Paratrichosoma recurvum occurrence in wild American crocodiles Crocodylus acutus from Mexican Caribbean islands and its relation to environmental (water salinity, temperature, climatic events) and biological (body condition) factors. The percentage of parasitized crocodiles (30.3%) is among the highest recorded in wild crocodilian populations. Small (<40.8 cm total length [TL]) and large (>270 cm TL) crocodiles are less parasitized, probably due to the characteristics of their skin or of the parasite life cycle. Two individuals appeared to have eliminated worms naturally between their capture and recapture. The thorax-abdomen is the most parasitized area of the body of crocodiles. The risk of infection is not associated with the sex of the crocodile, but there was a difference in the proportion of parasitized crocodiles between sites, which could be related to different environmental conditions. The body condition of a crocodile does not seem to be affected by the parasite. Climatic events and water temperature show no effect on the parasitism of crocodiles, but salinity could have an effect. The infection of crocodiles by P. recurvum could depend more on an individual's behavior than on environmental conditions.

Trichoscopic diagnosis of cutaneous Pelodera strongyloides infestation in a dog.

BACKGROUND: Pelodera strongyloides infestation has rarely been reported in dogs. It is a saprophytic free-living nematode, found in moist decaying organic matter, whose L3 larval stages occasionally can invade the skin of dogs and humans. Larvae penetrate the follicular infundibula causing an erythematous and pruritic dermatitis. The disease is usually diagnosed by deep skin scraping or histopathology, with large numbers of parasites readily identified in hair follicles. CASE REPORT: Pelodera strongyloides dermatitis was diagnosed in a six-year-old mixed breed dog presenting with alopecia, erythema and severe pruritus on the ventrum and limbs. The infestation was diagnosed by microscopic examination of plucked hair shafts and confirmed on microscopic examination of skin biopsies collected for histopathology. Only two of 10 deep skin scrapings gave positive findings. The nematode infestation was eradicated following two applications, 2 weeks apart, of a moxidectin/imidacloprid spot-on product. CONCLUSION AND CLINICAL IMPORTANCE: Skin scrapings are considered the diagnostic test of choice for P. strongyloides infestations. In this case, parasites were identified by hair trichograms more readily than by skin scrapings.

[Update on cutaneous dirofilariasis]. / La dirofilariose cutanée.

Dirofilariasis is a worldwide zoonotic infection that rarely affects humans and is caused by filarial nematodes of the genus Diroflaria transmitted by mosquitoes. Cutaneous dirofilariasis, due to D. repens, presents as inflammatory lesions that develop into subcutaneous nodules. These clinical symptoms may be consistent with Wells' cellulitis. Diagnosis of dirofilariasis involves demonstration of the presence of the nematode during skin biopsy and identification of the worm through macroscopic, histological and PCR analysis. Surgical resection of the nodule remains the gold standard treatment. The number of cases of human cutaneous dirofilariasis has increased in the recent years and the disease must not be misdiagnosed.

External injuries of Morelet's crocodile Crocodylus moreletii in Campeche, Mexico.

Analysis of external injuries in captive and free-ranging Morelet's crocodiles Crocodylus moreletii was performed in the northern wetlands of Campeche, Mexico. From March to September of 2007, a total of 52 free-ranging and 51 captive Morelet's crocodiles were studied. Captive crocodiles presented significantly more injuries. Sixteen free-ranging crocodiles presented some type of lesion, mostly superficial abrasions. Nineteen captive crocodiles presented lesions, mostly incisions from agonistic interactions. Overall, the injuries with highest prevalence were the incisions. The tail was the most frequently injured body region. Injuries were more common in adults than in other size classes. Conversely, the presence of lesions caused by the parasite Paratrichosoma spp. was greater in crocodiles captured in the coastal channels (mangrove habitat). The information presented here is important to understand some of the effects of individual interactions and to foresee and manage the consequences of conservation and management activities of crocodile populations.

Emergence of cutaneous neosporosis in a dog receiving immunosuppressive therapy: molecular identification and management.

BACKGROUND: Neosporosis is a multisystemic disease caused by the intracellular protozoan Neospora caninum. In dogs the disease primarily affects the central nervous system. Canine cutaneous neosporosis is a rare condition often associated with old age or concurrent immunosuppressive treatments for different underlying conditions. ANIMALS: A 10-year-old female spayed golden retriever dog affected by primary immune-mediated myelofibrosis and treated with immunosuppressive therapies for 6 weeks that developed severe cutaneous lesions. METHODS: Definitive diagnosis was based on several investigation techniques including serology (immunoblotting), immunohistochemistry (IHC), species-specific conventional and real-time PCR, and DNA sequencing. RESULTS: Remission of cutaneous neosporosis was obtained with the administration of clindamycin while the concurrent immunosuppressive therapy was maintained to manage the underlying primary condition. CONCLUSIONS AND CLINICAL IMPORTANCE: To the best of the authors' knowledge this is the first report of species-specific PCR and DNA sequencing used as diagnostic methods for canine cutaneous neosporosis emerging in a dog receiving immunosuppressive therapy.

Protozoal nodular dermatitis and panniculitis in a Rottweiler puppy caused by Caryospora bigenetica.

BACKGROUND: Caryospora bigenetica is an intracellular protozoan parasite in snakes and raptors (primary hosts) and rodents (secondary host). Experimental infection has been documented in mice, pigs and goats; natural infection in dogs is rare. OBJECTIVES: To describe the clinical presentation, histological features, treatment and outcome of a case of protozoal nodular dermatitis and panniculitis in a Rottweiler puppy caused by C. bigenetica. RESULTS: The puppy presented with generalized subcutaneous nodules measuring up to 2 cm in diameter. Histopathology revealed marked suppurative to pyogranulomatous dermatitis and panniculitis with intralesional protozoal organism. PCR and DNA sequencing confirmed infection with C. bigenetica. Treatment with a combination of oral trimethoprim-sulfamethoxazole (TMS), pyrimethamine and high-dose clindamycin (20 mg/kg twice daily) resulted in resolution of lesions in 6 weeks. Discontinuation of the treatment 2 weeks later was followed by a rapid relapse of skin lesions. Clindamycin and TMS were restarted and all lesions resolved within 2 weeks; TMS was discontinued 4 weeks later due to adverse effects. The lesions remained in remission for 2 months while the puppy received clindamycin monotherapy before a second relapse of skin lesions occurred. CONCLUSION AND CLINICAL IMPORTANCE: To the best of the authors' knowledge, this is the first documentation of the treatment and outcome of C. bigenetica cutaneous infection in a dog. Although remission of clinical signs can be achieved with combination therapy of clindamycin and TMS, long-term management is challenging and relapses should be anticipated.

Infections by Renibacterium salmoninarum and Nanophyetus salmincola Chapin are associated with reduced growth of juvenile Chinook salmon, Oncorhynchus tshawytscha (Walbaum), in the Northeast Pacific Ocean.

We examined 1454 juvenile Chinook salmon, Oncorhynchus tshawytscha (Walbaum), captured in nearshore waters off the coasts of Washington and Oregon (USA) from 1999 to 2004 for infection by Renibacterium salmoninarum, Nanophyetus salmincola Chapin and skin metacercariae. The prevalence and intensities for each of these infections were established for both yearling and subyearling Chinook salmon. Two metrics of salmon growth, weight residuals and plasma levels of insulin-like growth factor-1, were determined for salmon infected with these pathogens/parasites, both individually and in combination, with uninfected fish used for comparison. Yearling Chinook salmon infected with R. salmoninarum had significantly reduced weight residuals. Chinook salmon infected with skin metacercariae alone did not have significantly reduced growth metrics. Dual infections were not associated with significantly more severe effects on the growth metrics than single infections; the number of triple infections was very low and precluded statistical comparison. Overall, these data suggest that infections by these organisms can be associated with reduced juvenile Chinook salmon growth. Because growth in the first year at sea has been linked to survival for some stocks of Chinook salmon, the infections may therefore play a role in regulating these populations in the Northeast Pacific Ocean.

Genetics and infection dynamics of Paratrichosoma sp in farmed saltwater crocodiles (Crocodylus porosus).

Paratrichosoma-associated helminthiasis has been identified in saltwater crocodiles under intensive farming conditions. The development of sustainable integrated management practices is dependent on a detailed understanding of Paratrichosoma population genetics and infection dynamics. This study investigated the genetic relationships of Paratrichosoma sp in a population of commercially farmed saltwater crocodiles, Crocodylus porosus, in northern Australia. 18S ribosomal RNA gene sequence data were obtained from Paratrichosoma sp eggs present in the epidermis of infected animals. A high level of genetic diversity was distributed within the Paratrichosoma sp population (241 variable positions in the 1094 bp alignment), indicating an accelerated rate of nucleotide base-pair substitutions in this genus of nematodes. Several possible environmental correlates of the incidence and intensity of helminthiasis, including season, rainfall, and mean monthly temperature, were investigated by visual inspection of crocodile skins. Stepwise logistic regression revealed a significant negative linear relationship (P = 0.011, R (2) = 32.69 %) between mean monthly rainfall and the incidence of monthly Paratrichosoma-associated helminthiasis. Variation in the severity of Paratrichosoma-associated helminthiasis could not be explained by any of the independent environmental variables included within an ordinal regression analysis. The large genetic diversity in these nematodes indicates a high probability of anthelmintic resistant alleles occurring in the population. We discuss how the spread of these alleles may be mitigated by adopting targeted treatment protocols.

Risk factors associated with clinical dermatophilosis in smallholder sector cattle herds of Zimbabwe at the Amblyomma variegatum and Amblyomma hebraeum interface.

A cross-sectional study was conducted to investigate factors for clinical dermatophilosis herd-level positivity in smallholder dip tanks from Gokwe (Chemawororo, Gwanyika), Kwekwe (Koronika) and Chegutu (Chivero), Zimbabwe, between September 2013 and April 2014. A total of 185 herds were clinically examined for disease and tick infestation. Data on herd and potential herd level risk factors were collected using a structured questionnaire. A herd was classified as clinically positive if an animal satisfied any of the following criteria: small lesions characterised by hairs clumping like a small paint brush, clear exudative circumscribed lesions with scabs of at least 1 cm in diameter and confluent progressive exudative scab lesions affecting significant parts of the animal's body. Amblyomma variegatum and Amblyomma hebraeum ticks were identified in situ with further laboratory confirmation. The potential herd-level risk factors for clinical dermatophilosis were tested using multiple logistic regression with herd infection status (positive, negative) being the binomial outcome and risk factors being predictors. Of the herds examined, clinical bovine dermatophilosis was detected in 45 % (84/185, 95 % confidence interval (CI) 38.2, 52.6 %) of the herds. The herd prevalence ranged from 6.9 % (95 % CI 0.00, 16.7) to 56.7 % (95 % CI 43.8, 69.6) with Chivero and Chemawororo dip tanks recording the lowest and highest prevalence, respectively. Herds infested with A. variegatum were associated with higher odds (OR = 6.8, 95 % CI 1.71, 27.10) of clinical dermatophilosis while the association was not significant (p > 0.05) in A. hebraeum-infested herds. A history of having bought cattle (OR = 3.5, 95 % CI 1.09, 11.12) compared to not buying was associated with increased herd clinical positivity status. It was concluded that management practices aimed at movement and tick control would help reduce the prevalence of clinical dermatophilosis in cattle herds.

Morpho-molecular investigation of ectoparasitic infestation of companion animals in Sylhet city, Bangladesh.

Ticks (Ixodida) and Fleas (Siphonaptera) are considered among the most important arthropod of public health concern due to their ability to transmit vector-borne pathogens to humans. By sharing a common environment, vector-borne diseases constituted major setbacks to the development of a pet population in Bangladesh. This study aimed to determine companion animal-associated ticks and fleas based on morpho-molecular approaches. Between December 2021 and May 2022, 74 animals (62 cats and 12 dogs) were examined, of which 17 (27.4%) cats and 9 (75.0%) dogs had ectoparasitic infestations, with 35.1% overall prevalence. Morphometrical examination showed the ectoparasites in these animals were Ctenocephalides spp. (flea) and Riphicephalus spp. (tick). Genetic analysis using the mitochondrial markers i.e. Cytochrome c oxidase subunit 1 (cox1) revealed the presence of two flea species i.e., Ctenocephalides canis, Ctenocephalides felis, and one tick species Rhipicephalus sanguineus. Interviews of animal owners indicate that 35.14% of them had no concern about ectoparasitic infestation or ectoparasites-borne diseases. Our results indicated that fleas and ticks were the most common ectoparasites in companion animals of this area. The zoonotic nature of some ectoparasites can be regarded as a public health alert. The findings will assist epidemiologists and policymakers in offering customized guidance for upcoming monitoring and preventive tactics in this area.

Cutaneous and conjunctival habronemosis in horses treated at the Veterinary Hospital of the Santa Catarina State University, Brazil.

Habronemosis, also known as habronemiasis or habronematidosis, is a parasitic disease of equids caused by the larval stages of Habronematidae nematodes (Habronema muscae, Habronema microstoma, and Draschia megastoma) that are transmitted by muscid flies. The presence of aberrant infective larvae in the cutaneous and conjunctival tissues of these hosts results in granulomatous, exudative, and ulcerated lesions, also known as "summer sores." In this study, we present a retrospective analysis of habronemosis cases in horses from the municipality of Lages, located on the Santa Catarina Plateau, a region with high altitudes and a temperate climate that differs from regions of Brazil where such parasitosis usually occurs. The equids were examined from 2008 to 2020 at the Veterinary Hospital of Santa Catarina State University. Sixteen patients were diagnosed and treated using macrocyclic lactones and wound cleaning. Most cases were recorded in autumn in horses (10/16, 62.5%) over 15 years of age (11/16, 68.8%), and the lesions were more frequently located in the conjunctiva (11/16, 68.8%). In scientific dissemination media, this is the first report of habronemosis on the Santa Catarina Plateau, Brazil. This information will contribute to the diagnosis, treatment and prevention of skin diseases in horses in this region.

Microfilarial periodicity of Dirofilaria repens in naturally infested dogs.

In the past years, canine and human cases of infestation by Dirofilaria repens (Spirurida, Onchocercidae) have been increasingly reported in several European countries. Subcutaneous dirofilariosis by D. repens may either be asymptomatic in dogs or may be characterized by subcutaneous nodules and other symptoms. Information on the periodicity of D. repens microfilariae in naturally infested animals is scant, and this might impair the accurate diagnosis of subcutaneous dirofilariosis and appropriate control plans. In the present study, eight dogs infested with D. repens were sampled twice daily at 12-h intervals for ten consecutive days, and the dog with the highest mean value of microfilariaemia was further sampled every 4 h for four consecutive days. The blood was microscopically and molecularly examined for microfilariae, and, additionally, negative samples were also subjected to a real-time PCR to evaluate the level of circulating DNA. The results demonstrated significant variations in circadian rhythms of D. repens larvae, with higher values of microfilariae per milliliter in the evening samples. A significant variation was also found at the individual level for the dogs with the highest values of microfilariaemia. All samples which were negative at the light microscopy and positive at the real-time PCR displayed levels of circulating parasite DNA <1 microfilaria per milliliter. Biological and clinical implications have been here discussed.

Nodular lesions due to infestation by Dirofilaria repens in dogs from Italy.

BACKGROUND: Canine subcutaneous dirofilariosis caused by Dirofilaria repens is an important cause of human dirofilariosis in the Old World. OBJECTIVES: To describe the clinical and pathological features of infestation by D. repens in dogs with cutaneous nodules and to discuss key diagnostic procedures. ANIMALS: Sixteen privately owned dogs of different breeds, ages and genders with subcutaneous nodules were positive for D. repens on at least one diagnostic test. METHODS: Diagnostic tests included cytological examination of fine-needle aspiration biopsies, detection of circulating larvae by Knott's test, morphological and molecular identification of adult parasites and microfilariae, and histopathological examination of excised nodules. RESULTS: Twelve animals were positive for D. repens microfilariae, using cytology and at least one other diagnostic test. Four of twelve dogs screened by Knott's test had circulating D. repens microfilariae, and three of them were co-infected with Dirofilaria immitis. In eight dogs, adult nematodes were morphologically identified as D. repens. Nodular panniculitis was observed in all cases, with nodules containing either one or several cross-sections of nematodes and microfilariae. The nematodes extracted were identified as D. repens by an RT-PCR on the second internal transcribed spacer (ITS-2). CONCLUSIONS AND CLINICAL IMPORTANCE: Adults and larvae of D. repens can induce skin nodules in dogs, and these lesions should be carefully evaluated in endemic areas. Clinicians should be aware that correct tissue sampling (including the storage of part of a sample in ethanol instead of formalin) is pivotal to achievement of a specific diagnosis. Cytology of fine-needle tissue aspirates was shown to be useful.

Pelodera strongyloides infection in Pacific harbor seals (Phoca vitulina richardii) from California.

Skin biopsies were collected from free-ranging harbor seals (Phoca vitulina richardii) from central California (n = 53). Microscopic examination of hematoxylin and eosin-stained tissue sections revealed the presence of tightly coiled nematode larvae within the ostia of numerous hair follicles of four seals. Parasites were characterized by paired lateral alae, platymyarian musculature, and an indistinct, uninucleate digestive tract. Mild chronic superficial dermatitis and perifolliculitis were evident microscopically in association with the intrafollicular parasites. Histomorphologic features of the larvae and their presence within hair follicles are consistent with previous reports of the facultative nematode parasite Pelodera strongyloides. This is the first published report of P. strongyloides infection in any marine mammal. This parasite may be acquired by marine mammals through close contact with soil or decaying organic material and should be considered as a potential differential diagnosis for dermatitis in marine mammals that use terrestrial resting sites.