First record of larvae of Hysterothylacium (Nematoda: Anisakidae) with zoonotic potential in the pirarucu Arapaima gigas (Osteichthyes: Arapaimidae) from South America.

Third-stage larvae (L3) of Hysterothylacium sp. were collected by the first time in juveniles of pirarucu Arapaima gigas farmed in the Rio Preto da Eva, Amazonas state. Ninety-eight (98) out of 100 examined fish showed to be parasitized. Five hundred and ninety larvae of Hysterothylacium sp. were collected from the intestines, stomach and pyloric caeca. The mean intensity of parasite indexes was 6.02 (±5.75) ranging from 1 to 40 larvae per host and the mean abundance was 5.9 (±5.76). The A. gigas is the new host record for larvae of Hysterothylacium sp. in Brazil, and this is the first record of larvae of Hysterothylacium (Nematoda: Anisakidae) with zoonotic potential in the pirarucu from South America.

First record of larvae of Hysterothylacium (Nematoda: Anisakidae) with zoonotic potential in the pirarucu Arapaima gigas (Osteichthyes: Arapaimidae) from South America / Primeiro registro de larvas de Hysterothylacium sp.(Nematoda: Anisakidae) com potencial zoonótico em pirarucu Arapaima gigas (Osteichthyes: Arapaimidae) na América do Sul

Abstract Third-stage larvae (L3) of Hysterothylacium sp. were collected by the first time in juveniles of pirarucu Arapaima gigas farmed in the Rio Preto da Eva, Amazonas state. Ninety-eight (98) out of 100 examined fish showed to be parasitized. Five hundred and ninety larvae of Hysterothylacium sp. were collected from the intestines, stomach and pyloric caeca. The mean intensity of parasite indexes was 6.02 (±5.75) ranging from 1 to 40 larvae per host and the mean abundance was 5.9 (±5.76). The A. gigas is the new host record for larvae of Hysterothylacium sp. in Brazil, and this is the first record of larvae of Hysterothylacium (Nematoda: Anisakidae) with zoonotic potential in the pirarucu from South America.

Resumo Larvas de terceiro estágio (L3) de Hysterothylacium sp. foram coletadas pela primeira vez em juvenis de pirarucu Arapaima gigas cultivados no Rio Preto da Eva, Estado do Amazonas. Noventa e oito (98) dos 100 peixes examinados estavam parasitados. Quinhentos e noventa larvas de Hysterothylaciumsp.foram coletados no intestino, estômago e cecos pilóricos. O índice parasitário de intensidade média foi de 6,02 (±5,75) variando de 1 a 40 larvas por hospedeiro e o de abundância média foi de 5,9 (±5,76). A. Gigas é um novo registro de hospedeiro para larvas de Hysterothylacium sp. no Brasil, também sendo, o primeiro registro de larvas de Hysterothylacium sp. com potencial zoonótico em pirarucu da América do Sul.

Ultrastructure of reproductive system of female Litomosoides chagasfilhoi Moraes-Neto, Lanfredi and De Souza, 1997 (Nematoda: Filarioidea).

The ultrastructure of the female reproductive system of the filariid Litomosoides chagasfilhoi by transmission electron microscopy (TEM) is described for the first time. The ovary is composed of primary oocytes surrounded by a single layer of epithelial cells apposed on the basal laminae. The ovarian wall is completely filled with primary oocytes, which are arranged radially and are centrally connected around the rachis. The uterine wall consists of muscular fibers surrounded by a basal lamina and the epithelium underlying the lamina. Ameboid and aflagellate spermatozoa are present inside the distal portion of the uterus, some of them near oocytes, which present bacteria in its cytoplasm. An eletrondense well-defined eggshell covers the zygotes, which presents in its cytoplasm bacteria arranged in groups. These bacteria are also observed in embryos and in the hypodermal cord. These ultrastructural aspects of L. chagasfilhoi female worms presented herein contribute to the knowledge of the morphology and embryonary development of this filariid, providing means for further comparative analyses of the action of anti-filarial drugs. Besides this, the presence of bacteria Wolbachia-like is being reported for the first time in this species, showing the great importance of this experimental model of study.

Further description of Aspidodera raillieti (Nematoda: Aspidoderidae) from Didelphis marsupialis (Mammalia: Didelphidae) by light and scanning electron microscopy.

Nematodes of the family Aspidoderidae (Nematoda: Heterakoidea) Freitas 1956 are widely distributed from Americas. The species of the genus Aspidodera Railliet and Henry 1912 are parasites of mammals of the orders Edentata, Marsupialia, and Rodentia. In the present work, Aspidodera raillieti (L. Travassos, Mem Inst Oswaldo Cruz 5(3):271-318, 1913), collected from the large intestine of Didelphis marsupialis (Mammalia: Didelphidae) from Valle del Cauca, Colombia, is redescribed. The association of light and scanning electron microscopy (SEM) allowed a detailed analysis of the morphology and ultrastructure of this nematode. Some taxonomic features, such as cephalic region, topography of the cuticle, sucker, spicules, posterior end of males, localization of vulva, the anus, and posterior end of females were observed. Important structures such as amphid, details of cephalic region, phasmid, and number and localization of caudal papillae are documented by SEM, for the first time adding characters to identify this species. Colombia is a new geographical record for A. raillieti.

Ultrastructure of Procamallanus (Spirocamallanus) halitrophus (Nematoda: Camallanidae) parasite of flounder.

The ultrastructure of the camallanid nematode Procamallanus (Spirocamallanus) halitrophus, a parasite of flounder, is described for the first time by the use of transmission electron microscopy. The body wall is composed of an outer cuticle, a hypodermis, and a muscular layer. The cuticle comprises the epicuticle, the cortical, median, fibrous, and basal layers. The cortical layer is subdivided into an outer zone and an inner zone; the median layer is subdivided into an outer layer, rich in electrondense fibrils, and an inner layer, which does not contain these fibrils; the fibrous layer is subdivided into three regions delimited by electrondense lines; the basal layer presents electrondense sustaining structures. Underlying the basal layer is the hypodermis where many organelles are observed. The musculature is striated, and each muscle cell consists of individualized contractile and non-contractile regions. Inclusion bodies are present in the muscle fibers, hypodermis, hypodermal chord, and in the intestine.

Further description of Procamallanus (Spirocamallanus) halitrophus comb. n. (Nematoda: Camallanidae) from flounder off the Brazilian coast by light and scanning electron microscopy.

Procamallanus (Spirocamallanus) halitrophus Fusco and Overstreet, 1978 from the intestines of flounders (Syacium papillosum and Citharichthys macrops) from the coast of the State of Rio de Janeiro, Brazil, is redescribed. This study, which is based on results obtained by light and scanning electron microscopy, clarifies many morphological aspects of this species. Some taxonomic features, such as the cephalic structures, the topography of the cuticle, the vulva, the localization of caudal papillae on males, and the excretory pore, are observed for the first time. C. macrops represents a new host record, and Rio de Janeiro is a new geographical record for this species.

Pseudempleurosoma gibsoni n. sp., a new ancyrocephalid monogenean from Paralonchurus brasiliensis (Sciaenidae) from off the southeastern coast of Brazil.

Pseudempleurosoma gibsoni n. sp. (Monogenea: Ancyrocephalidae) is described from the oesophagus of Paralonchurus brasiliensis (Steindachner) from off the coast of Brazil. The type-species of Pseudempleurosoma Yamaguti, 1965, P. carangis Yamaguti, 1965, is redescribed and the diagnosis of the genus is amended. Metadiplectanotrema Gerasev et al. 1987 is considered synonym of Pseudempleurosoma. This genus now contains four species, including P. carangis, P. caranxi Gerasev et al., 1987 n. comb., P. myripristi Gerasev et al., 1987 n. comb. and the one new species.

Studies on Procamallanus (Spirocamallanus) Pereirai annereaux, 1946 (Nematoda: Camallanidae), with new host records and new morphological data on the larval stages.

Larval stages and adults of Procamallanus (Spirocamallanus) pereirai Annereaux, 1946 are described from naturally infected Paralonchurus brasiliensis (Steindachner) (Sciaenidae) from the coast of the State of Rio de Janeiro, Brazil. The translucent first-stage larvae have a denticulate process at the anterior end, no buccal capsule or esophagus undifferentiated into anterior muscular and posterior glandular parts and an elongate tail; third-stage larvae have a tail with three terminal projections, a buccal capsule divided into an anterior portion with 12-20 ridges running to the left and a posterior smooth portion, and an esophagus with muscular and glandular regions. Fourth-stage larvae exhibit a buccal capsule lacking a distinct basal ring with ridges running to the right and a tail with two terminal processes, as in adults. New host records are reported and their role in its life-cycle are discussed.