Human infection with Pseudoterranova cattani by ingestion of "ceviche" in Buenos Aires, Argentina / Infección humana con Pseudoterranova cattani por ingesta de ceviche en Buenos Aires, Argentina

Abstract Anisakidosis is an infection caused by larval nematodes that belong to several genera within the family Anisakidae. Anisakidosis has about 20000 cases reported to date, the vast majority (90%) in Japan. Usually, human anisakiosis is more common than human pseudoterranovosis in Japan and Europe, although in North America Pseudoterranova spp. is the more frequent. Cases of human pseudoterranovosis have been reported from Chile and Peru. We here report one of the few cases of human infection by Pseudoterranova cattani by consumption of ``ceviche'' in Buenos Aires, Argentina.

Resumen La anisakidosis es una infección por larvas de nematodos que pertenecen a varios géneros dentro de la familia Anisakidae. Se han registrado aproximadamente 20.000 casos hasta la fecha, la mayoría (90%) en Japón. En Europa y Japón la anisakidosis es más frecuente en el humano que la pseudoterranovosis. En cambio, en América del Norte es más frecuente la infección humana por Pseudoterranova spp. También se han informado casos de pseudoterranovosis humana en Chile y en Perú. Informamos uno de los pocos casos de infección humana por Pseudoterranova cattani por consumo de ceviche en Buenos Aires, Argentina.

Toxocariasis ocular. A propósito de un caso / Ocular toxocariasis. Case report

RESUMEN Se presentó un caso clínico de un paciente de seis años de edad, con toxocariasis ocular. La manifestación clínica fue disminución de la agudeza visual monocular. El fondo de ojo izquierdo mostró un granuloma retiniano periférico, asociado a un desgarro retiniano perilesional. El examen oftalmológico confirmó el diagnóstico de Toxocara ocular. El paciente fue tratado posteriormente mediante corticoides sistémicos y fotocoagulación láser focal en el desgarro retiniano (AU).

ABSTRACT We present the clinical case of a male patient, aged 6 years, with ocular toxocariasis. The clinical manifestation was monocular visual acuity decrease. The left ocular fundus showed a peripheral retina granuloma, associated to a perilesional retinal tear. The ophthalmological examination confirmed the diagnosis of ocular Toxocara. After that the patient was treated using systemic corticoids and focal laser coagulation in the retinal tear (AU).

Histopathological changes induced by Hysterothylacium deardorffoverstreetorum larvae (Nematoda: Raphidascarididae) in Priacanthus arenatus Cuvier, 1829 (Actinopterygii) / Alterações histopatologicas induzidas por larvas de Hysterothylacium deardorffoverstreetorum (Nematoda: Raphidascarididae) em Priacanthus arenatus Cuvier, 1829 (Actinopterygii)

Abstract Priacanthus arenatus is a fish that occurs in the waters of the western Atlantic Ocean and has few records of parasitism. This study aimed to report histological changes caused by the larvae of Hysterothylacium deardorffoverstreetorum. Between July and December, 2013, 30 samples of P. arenatus were obtained from fish markets in the cities of Niterói and Rio de Janeiro, state of Rio de Janeiro, Brazil. Fragments of spleen, liver, stomach wall and mesentery tissues containing nodules and free parasites were extracted to histopathological study. Through histological analysis it was verified that these nodules consisted of connective tissue capsules, in which the parasites were located, with granulomatous inflammation mainly comprised of macrophages and lymphocytes. These nodules also consisted of a central portion of acellular amorphous material, formed by concentric layers, which was slightly basophilic and contained tunnels and, sometimes, parasite debris. The presence of tunnels in acellular amorphous material suggests that the larvae are initially located at the center of the nodules and then they migrate to the surface.

Resumo Priacanthus arenatus é um peixe que ocorre nas águas do Atlântico ocidental com poucos relatos de parasitimo. Este estudo objetivou relatar as características histológicas causadas pelas larvas de H. deardorffoverstreetorum em P. arenatus. Entre julho e dezembro de 2013, 30 espécimes de P. arenatus foram obtidas de mercados de peixes das cidades de Niterói e Rio de Janeiro, Estado do Rio de Janeiro, Brasil. Fragmentos de baço, fígado, parede do estômago e mesentério contendo nódulos foram extraídos para estudo histopatológico. Foi observado através de análise histológica que esses nódulos eram constituídos por uma cápsula de tecido conjuntivo, onde se localizavam os parasitas viáveis, com infiltrado inflamatório granulomatoso, constituído, predominantemente, por macrófagos e linfócitos e por porção central de material amorfo acelular, formado por lâminas concêntricas, ligeiramente basofílico, contendo túneis e, por vezes, restos parasitários. A presença de túneis no material amorfo acelular dos nódulos analisados histologicamente sugerem que as larvas se localizam inicialmente no centro do granuloma e depois migram para a superfície do mesmo.

First record of Hysterothylacium sp. Moravec, Kohn et Fernandes, 1993 larvae (Nematoda: Anisakidae) infecting the ornamental fish Hyphessobrycon eques Steindachner, 1882 (Characiformes, Characidae) / Primeiro registro de larvas de Hysterothylaciumsp. Moravec, Kohn et Fernandes, 1993 (Nematoda: Anisakidae) infectando o peixe ornamental Hyphessobrycon eques Steindachner, 1882 (Characiformes, Characidae)

AbstractThis study reports for the first time infection with Hysterothylacium sp. larvae in the ornamental fish Hyphessobrycon eques from the Paranapanema River, Jurumirim Reservoir, São Paulo State, Brazil. A sample of 33 specimens of H. eques was collected in October, 2011. Four specimens of H. eques were parasitized by Hysterothylacium sp. larvae in the intestine and coelomic cavity, with prevalence of 12.1%, mean intensity of infection of 1, and mean abundance of 0.121 ± 0.05. A total of 40 unidentified free-living nematodes were found in the stomach content of 17 fish. This fish species is introduced in the Paranapanema River. Invasive species may affect the native fauna given the introduction of pathogens and parasites. This study also complements data on the diet of H. eques due to the records of free-living nematode as part of the stomach content. Infections with Hysterothylacium sp. larvae may affect the biology of this fish and bring about profit losses to aquarists.

ResumoEste estudo reporta pela primeira vez infecção com larva de Hysterothylacium sp. no peixe ornamental Hyphessobrycon eques do rio Paranapanema, reservatório de Jurumirim, estado de São Paulo, Brasil. Uma amostra de 33 spécimens de H. eques foi coletada em Outubro de 2011. Quatro espécimes de H. eques estavam parasitados por larva de Hysterothylacium sp. no intestino de cavidade celomática, com prevalência baixa de 12,1%, intensidade média de infecção de 1 e abundância média de 0,121 ± 0,05. Um total de 40 nematóides livres não identificados foi encontrado no conteúdo estomacal de 17 peixes. Esta espécie de peixe é introduzida no rio Paranapanema. Espécies invasoras podem afetar a fauna nativa dada a introdução de patógenos e parasitas. Este estudo também complementa os dados de alimentação de H. eques devido os registros de nematoides de vida livre como parte do conteúdo estomacal. Infecções com larva de Hysterothylacium sp. afetam a biologia deste peixe e pode ocasionar prejuízos para aquaristas.

Morphological and molecular diagnosis of Pseudoterranova decipiens (sensu stricto) (Anisakidae) in imported cod sold in Brazil / Diagnose morfológica e molecular de Pseudoterranova decipiens (sensu stricto) (Anisakidae) em bacalhau importado vendido no Brasil

An anisakid nematode larva found in cod sold in the state of Minas Gerais, Brazil was studied by light and scanning electron microscopy and by a molecular approach. Mitochondrial cytochrome c-oxidase subunit 2 (mtDNA cox-2), 28S rRNA and ITS1, 5.8S and ITS2 regions were amplified using the polymerase chain reaction and sequenced to evaluate the phylogenetic relationships of the larva. The genetic profile confirmed that this larva belongs to the species Pseudoterranova decipiens (sensu stricto). This is the first molecular and ultrastructural study of Pseudoterranova decipiens (sensu stricto) in imported cod sold in Brazil. The health implications of these findings are discussed.

Uma larva de Nematoda anisakídeo encontrada em bacalhau comercializado no Estado de Minas Gerais, Brasil foi estudada por microscopias de luz e eletrônica de varredura e por uma abordagem molecular. As regiões da subunidade 2 da citocromo c-oxidase mitocondrial (mtDNA cox-2), 28S rRNA e ITS1, 5.8S e ITS2 foram amplificadas usando a reação em cadeia da polimerase e sequenciadas para avaliar as relações filogenéticas da larva. O perfil genético confirmou que esta larva pertence à espécie Pseudoterranova decipiens (sensu stricto). Esse é o primeiro estudo molecular e ultraestrutural de Pseudoterranova decipiens (sensu stricto) de bacalhau importado vendido no Brasil. As implicações destes resultados para a saúde são discutidas.

Geohelmintíases em trabalhadores de limpeza pública na cidade de Parnaíba, Piauí: prevalência e fatores de risco / Geohelmintíases public cleaning workers in Parnaíba, Piauí: prevalence and risk factors

As geohelmintíases são doenças de alta prevalência em populações de vulnerabilidade econômica e social, por estarem diretamente relacionadas a precárias condições higiênico-sanitárias, além de baixo nível educacional e econômico, sendo consideradas doenças negligenciadas. No intuito de estimar a prevalência, grau de infecção e fatores associados às geohelmintíases em funcionários de limpeza pública na cidade de Parnaíba –Piauí – Brasil, realizou-se estudo seccional, de abordagem quantitativa, em população de 163 indivíduos nesta atividade. Verificou-se prevalência geral de 35,58 por cento de geohelmintíases, sendo 6,75 por cento das 163 amostras analisadas positivas para mais de um tipo de geohelminto. A prevalência de cada uma das três geohelmintíases principais foi de 25,15 por cento para ascaridíase, 7,36 por cento para tricuríase e 9,82 por cento para ancilostomíase, enquanto o grau de intensidade de infecção foi considerado leve em todas. Entre as características sociodemográficas, ocupacionais e clínicas analisadas, evidenciou-se que os indivíduos com maior prevalência de geohelmintíases dentre os avaliados foram os garis, quando comparados a motoristas e tratoristas, além de os pertencentes a classes sociais mais baixas e aqueles que tinham mais de 60 meses desde o último tratamento antiparasitário. Dessa forma, demonstrou-se a vulnerabilidade dos funcionários de limpeza pública em relação à endemia de geohelmintíases em virtude tanto de sua condição socioeconômica como da atividade profissional...

The soil-transmitted helminthiases (STH) are highly prevalent diseases in populations of economic and social vulnerability, because they are directly related to poor sanitary conditions, and low educational and economic level and are considered Neglected Diseases. In order to estimate the prevalence, degree of infection and factors associated with STH in public sanitation workers in the city of Parnaíba -Piauí - Brazil was held sectional study with a quantitative approach in a population of 163 individuals in this activity. It was found the overall prevalence of STH of 35.58 percent, with 6.75 percent of 163 samples tested positive for more than one type of helminth. The prevalence of each of the three main STH was 25.15 percent for ascariasis, trichuriasis, and 7.36 percent to 9.82 percent for hookworm, while the intensity of infection was considered mild in all. Among the sociodemographic, occupational and clinical characteristics analyzed, it was shown that individuals with higher prevalence of STH among the evaluated were the street sweepers, compared to drivers and tractor drivers, as well as those belonging to lower social classes and those who had more than 60 months since the last antiparasitic treatment. Thus, it was demonstrated the vulnerability of public cleaning staff in relation to endemic STH by virtue of both their socioeconomic status as professional activity...

A Case of Anisakidosis Caused by Pseudoterranova decipiens Larva

Pseudoterranova decipiens larva is a rare cause of anisakiasis. Indeed, prior to the present study, there had been only 12 reports of larval P. decipiens infection in the Republic of Korea. In June 2011, an anisakid larva, 32.1 mm in length and 0.88 mm in width, and finally identified as the third stage larva of P. decipiens owing to the presence of an intestinal cecum but lacking ventricular appendage, was discovered in a 61-year-old woman during the course of endoscopy executed as a part of routine physical examinations. The patient had eaten raw a rockfish 13 hr prior to the endoscopy, but showed no symptoms of anisakiasis. This paper is the 13th report of P. decipiens infection in Korea.

The first report of new species: Trichuris landak n. sp

<p><b>OBJECTIVE</b>To study nematode parasites morphology of Hystrix javanica (H. javanica), both through the feces and internal organs.</p><p><b>METHODS</b>Feces were observed by direct smear method, internal organs were observed after dissecting the host. Specimens for light microscopy examination were fixed with 70% warm alcohol, cleared and mounted in lactophenol for wet mounting. Specimens for SEM examination were postfixed in cacodylate buffer and glutaraldehyde, dehydrated through a graded series of alcohol and freeze dried. The specimens were attached to stubs with double cello-tape, coated with gold and observed with a JSM5310 LV electron microscope. Figures were made with the aid of a drawing tube attached to Olympus compound microscope, other figures were photographs of scanning electron microscope images. Measurements were given in micrometers as the mean followed by the range in parentheses, unless otherwise stated.</p><p><b>RESULTS</b>The nematode species found in the intestine of H. javanica are Gireterakis girardi and a new species, Trihuris landak. The new species differs with previously reported species from Hystrix because of having stylet and short cervical alae. The pattern of bacillary band is closed to Trichuris trichiurus, the species that infect human, but differs because the surface of its vulva is not covered with densely spine.</p><p><b>CONCLUSIONS</b>The species of nematodes found on H. javanica were Gireterakis girardi and a new species Trichuris landak n.sp. Those two species are newly recorded in Indonesia.</p>

Lagochilascaris minor Leiper, 1909 (Nematoda: Ascarididae) in Mexico: three clinical cases from the Peninsula of Yucatan / Lagochilascaris minor Leiper, 1909 (Nematoda: Ascarididae) en México: tres casos clínicos de la Península de Yucatán

Human lagochilascariasis (HL) is a parasite produced by Lagochilascaris minor Leiper 1909 that also can be found in cats and dogs. HL is considered an emerging zoonosis in the Americas, spreading from Mexico to Argentina, and the Caribbean Islands. The present paper describes three HL cases from the Peninsula of Yucatan, Mexico, recorded in the last decade. It describes the characteristics of the lesions and discusses the route of transmission in humans and particularly in the observed patients.

La Lagochilascariasis humana (HL) es producida por Lagochilascaris minor Leiper, 1909; el cual es un parásito que puede ser encontrado también en gatos y perros. HL es considerada una zoonosis emergente en América distribuida desde México hasta Argentina y las islas del Caribe. El presente artículo describe tres casos de HL en la Península de Yucatán, México registrados en la última década. Se describen las características de las lesiones y se discute la ruta de transmisión en humanos y particularmente en los pacientes observados.

Comparative Efficacy of Ivermectin and Levamisole for Reduction of Migrating and Encapsulated Larvae of Baylisascaris transfuga in Mice

The comparative efficacy of 2 anthelmintics (ivermectin and levamisole) against Baylisascaris transfuga migrating and encapsulated larvae was studied in mice. A total of 60 BALB/c mice inoculated each with about 1,000 embryonated B. transfuga eggs were equally divided into 6 groups (A-F) randomly. Mice of groups A and B were treated with ivermectin and levamisole, respectively, on day 3 post-infection (PI). Mice of groups A-C were killed on day 13 PI. Similarly, groups D and E were treated with ivermectin and levamisole, respectively, on day 14 PI, and all mice of groups D-F were treated on day 24 PI. The groups C and F were controls. Microexamination was conducted to count the larvae recovering from each mouse. The percentages of reduction in the number of migrating larvae recovered from group A (ivermectin) and B (levamisole) were 88.3% and 81.1%, respectively. In addition, the reduction in encapsulated larvae counts achieved by ivermectin (group D) and levamisole (group E) was 75.0% and 49.2%, respectively. The results suggested that, to a certain extent, both anthelmintics appeared to be more effective against migrating larvae than encapsulated larvae. However, in the incipient stage of infection, ivermectin may be more competent than levamisole as a larvicidal drug for B. transfuga.

Concurrent Capillaria and Heterakis Infections in Zoo Rock Partridges, Alectoris graeca

Two adult rock partridges raised in a city zoo were examined parasitologically and pathologically. Two distinctive eggs resembling those of Capillaria and Heterakis were detected in the feces. At necropsy, a markedly-dilated duodenum with severe catarrhal exudates, containing adult worms of Capillaria sp. and Heterakis sp. in the cecum, was observed. Male Capillaria had the cloacal aperture extended almost terminally with a small bursal lobe and an unsheathed spicule with transverse folds without spines. Female Capillaria had a vulva that was slightly prominent and slightly posterior to the union of the esophagus and intestine. The esophagus of the adult Capillaria was more than a half as long as the body in the male, but was much shorter in the female. Based on these morphological features, the capillarid nematode was identified as Capillaria obsignata. The male adult worms of Heterakis was identifiable by 2 dissimilar spicules, a unique morphological feature where the right spicule was considerably longer than the left, which is also a characteristic feature of Heterakis gallinarum. This is the first report of concurrent infections with C. obsignata and H. gallinarium in rock partridges.

Experimental lagochilascariosis in X-chromosome-linked immunodeficient mice / Lagochilascariose experimental em camundongos com imunodeficiência ligada ao cromossomo X

Lagochilascaris minor is the etiological agent of lagochilascariosis, a disease that affects the neck region and causes exudative abscesses, with eggs, adult parasites and L3/L4 larvae in the purulent exudates. Mice are now considered to be intermediate hosts for the parasite. To determine the pattern of infection in B1 cell-deficient mice, experimental lagochilascariosis was studied in BALB/c and X-chromosome-linked immunodeficient (xid) mice. BALB.xid-infected mice showed lower numbers of larvae. Third-stage larvae, fourth-stage larvae and adult parasites were found in both strains. BALB/c mice produced IgM, IgG, IgA and IgE against the crude extract and secreted/excreted antigens of the parasite. On the other hand, BALB.xid mice did not produce IgM and produced lower levels of IgG and IgA, and similar quantities of IgE.

Lagochilascaris minor é o agente etiológico da lagochilascariose, uma doença que afeta a região de pescoço provocando abscessos exudativos contendo ovos, parasitas adultos e larvas L3/L4 nos exudates purulentos. Atualmente, camundongos são considerados hospedeiros intermediários do parasita. Para determinar o padrão de infecção em camundongos deficientes de células B1, a lagochilascariose experimental foi estudada em camundongos BALB/c e em camundongos com imunodeficiência ligada ao cromossomo X (xid). Camundongos BALB.xid infectados mostraram menor número de larvas. Larvas L3, L4 e parasitas adultos foram encontrados em ambas as linhagens. Camundongos BALB/c produziram IgM, IgG, IgA e IgE contra o extrato bruto e antígenos secretados/excretados do parasita; por outro lado, camundongos BALB.xid não produziram IgM, produziram baixos níveis de IgG e IgA, e quantidades semelhantes de IgE.

Lagochilascariasis leading to severe involvement of ocular globes, ears and meninges / Infecção humana por Lagochilascaris minor com envolvimento ocular, auditivo e das meninges

A case report of a 31 year-old woman from Paraíba State (North-Eastern Brazil) that presented severe involvement of ocular globes, ears and meninges. Diagnosis was established after enucleation of her left eye, when adult worms were seen in the midst of a granulomatous inflammatory process. Her response to the initial treatment with levamisole and cambendazole was good, but there was a relapse after the fifth month of treatment even with maintenance doses of both medications. She later received ivermectin and albendazol and responded well.

Paciente do sexo feminino, com 31 anos, procedente da Paraíba, apresentava envolvimento severo de ambos os globos oculares, com perda da visão à esquerda, comprometimento da audição e das meninges. Após enucleação do olho esquerdo fragmento de helminto identificado como Lagochilascaris minor foi observado em processo inflamatório granulomatoso. Inicialmente a paciente foi tratada com levamisol e cambendazol, com bom resultado. Verificou-se, todavia, piora do quadro após cinco meses, com eliminação de larvas do ascarídeo em lesão presente na órbita esquerda, embora a medicação fosse mantida com administração periódica. Houve boa resposta terapêutica, com regressão do quadro, após substituição dos anti-helmínticos anteriores pela associação ivermectina e albendazol.

Perfil hematológico, bioquímico sérico e sorológico de Felis domesticus com lagochilascariose experimental / Hematological, serum biochemical and serological profile of Felis domesticus with experimental lagochilascariosis

No presente trabalho, avaliou-se o hemograma, diversas proteínas e enzimas séricas ou plasmáticas e a produção de anticorpos específicos em Felis domesticus, experimentalmente infectados por Lagochilascaris minor. Verificou-se nos animais infectados aumento de leucócitos totais, principalmente eosinófilos; queda do número de plaquetas; aumento de aspartato-aminotransferase e alanina-aminotransferase; e principalmente a presença de anticorpos IgG específicos para antígenos do parasita. A reação com extrato bruto de parasitas adultos mostrou-se mais específica, permitindo a discriminação de soros de animais: não infectados, com infecção por outros parasitas, e com lagochilascariose. Esta é a primeira descrição da padronização de uma reação sorológica para diagnóstico da lagochilascariose em Felis domesticus.

The present study evaluated the hemogram, different proteins, plasma enzymes, serum enzymes and specific antibody production of Felis domesticus experimentally infected by Lagochilascaris minor. The infected animals were seen to present increased total leukocytes (particularly eosinophils), decreased platelet counts, increased aspartate-aminotransferase and alanine-aminotransferase and, especially, the presence of specific IgG antibodies against antigens of the parasite. The reaction with crude extract of adult parasites was shown to be more specific, thereby enabling serum discrimination between the animals: non-infected, infected with other parasites and infected with lagochilascariosis. This is the first description of the standardization of a serological reaction for diagnosing lagochilascariosis in Felis domesticus.

Gastrointestinal impaction by Parascaris equorum in a Thoroughbred foal in Jeju, Korea

A weanling Thoroughbred foal was admitted to Equine Hospital, Korea Racing Association with signs of colic. On admission the foal was sweating profusely, appeared anxious and exhibiting signs suggestive of abdominal pain. Clinical examination revealed: tachycardia (90 beats/min), tachypnea (50 breaths/min) and congested and slightly cyanotic mucous membranes. No intestinal sounds were auscultated in all 4 abdominal quadrants. Rectal palpation identified concurrent cecum and large colon impactions. Treatment consisted of intravenous administration of a balanced electrolyte solution, nasogastric siphonage and administration of analgesics. Nasogastric reflux contained ascarids. This treatment failed to alleviate the signs of colic. The foal died 3 hours later following discharge because the owner didn't want laparatomy because of economic constraints. Prior to admission this foal had not received any prophylactic anthelmintic treatment. In necropsy, there were masses of ascarids accumulation in the stomach, small intestine and large intestine. The outcome of this report is to describe the first diagnosed case of gastrointestinal impaction by P. equorum in a Thoroughbred foal in South Korea and indicates the importance of regular anthelmintic treatment.

A new nematode species Goezia leporini n. sp. (Anisakidae) from cultured freshwater fish Leporinus macrocephalus (Anostomidae) in Brazil

This paper describes nematode infection in the cultured freshwater fish Leporinus macrocephalus (Osteichthyes: Anostomidae) collected at Batatais, São Paulo State, Brazil. Of a total of 32 examined fish, 21 (65 percent) were infected with Goezia leporini n. sp. (Nematoda: Anisakidae) with mean infection intensity of 4.1 parasites. The nematodes presented total length greater than G intermedia, G. holmesi, G. pelagia, G. minuta, G. kliksi, G. sinamora, G. nonipapillata, G. alii, G. moraveci, G. brasiliensis, and G. brevicaeca. The main difference was a great number of preanal papillae in males when compared to G. brasiliensis and G. brevicaeca. The present description also differs from that of G. brasiliensis with respect to spicule length and distance of vulva from the anterior extremity.

First report of Lappetascaris lutjani Rasheed, 1965 (Nematoda, Ascaridoidea, Anisakidae) parasitizing Trachipterus arawatae (Pisces, Lampridiformes) on the Atlantic Coast of Brazil

New host and geographical records are reported for the nematode Lappetascaris lutjani Rasheed, 1965, parasitizing the marine fish Trachipterus arawatae Clark, 1881 in Brazilian waters. Morphometric data and illustrations of the parasites are included

Human infection by Pseudoterranova decipiens (Nematoda, Anisakidae) in Chile: report of seven cases

From 1997 to 1999, we identified seven human cases of infection by fourth stage larvae of Pseudoterranova decipiens in Chile. All identified larvae were coughed up by the patients. Subjects were 10-55 years old; five were female. Some patients complained of coughing, expectoration, pharyngeal pain, nausea or anal and nasal pruritus. Larvae of three patients were coughed up from 36 h to 7 days after having eaten raw (cebiche or sushi) or lightly fried fish. P. decipiens has a marine life cycle. Infective third stage larva develop to adult stage in pinniped mammals. The nematode eggs are voided with the host faeces and develop and hatch releasing third stage larvae. Some crustaceans and fish act as hosts of third stage larvae. Man is an accidental host for third or fourth stage larvae