On Temnocephala axenos Monticelli, 1898 (Platyhelminthes, Temnocephalida): taxonomic status and designation of a neotype.

Temnocephala axenos Monticelli, 1898 was described based on specimens from an unidentified host collected in Blumenau, Santa Catarina, Brazil. Information about type locality was imprecise and the host was later identified as Aegla laevis (Latreille, 1818). However, it is known that A. laevis is not present on the eastern side of the Andes. Also, only histological preparations from one specimen studied by Monticelli are currently available in the Museum für Naturkunde Berlin, but it showed none of the taxonomic characters needed for the characterization of the species. Although the updated description of the species based on Uruguayan specimens, neither the author nor the several previous studies about the species showed a search for the type material, a resolution for the misidentification of the type host or the imprecise type locality due to the subsequent geographical division of the municipality cited in the description. The Uruguayan specimens were not even geographically close to the type locality and a neotype was not designed to validate the species' taxonomic status again. Specimens from Santa Catarina and Paraná States, Brazil, were studied, as well as restudied Argentinean specimens. The new data were compared with the update description of the species. The historical background and the discussion about geographical origins and hosts of the species, as well as a designation of a neotype, allow comparative material of the type locality and type host to exist, eliminating doubts about the identification of T. axenos.

Helminth fauna of Megaleporinus obtusidens (Characiformes: Anostomidae) from Lake Guaíba: analysis of the parasite community.

ABTRACT: Structure of the helminth community of Megaleporinus obtusidens collected in Lake Guaíba was evaluated, and the results indicated that the diversity of helminth species was probably determined by fish behavior and eating habits. The influence of sex, weight, and standard length of hosts for parasitic indices was also analyzed. Sixteen helminth species were found parasitizing M. obtusidens, including the following: platyhelminths, with the highest richness, represented by one species of Aspidobothrea; four species of Digenea; and eight species of Monogenea; the latter, presented the highest prevalence. Rhinoxenus arietinus, found in nasal cavities, had the greater abundance, and was the only species classified as core. The prevalence of Urocleidoides paradoxus was significantly influenced by the sex of the host; females had the highest values. Abundance was weakly influenced by fish weight and the body length of the hosts. Urocleidoides sp. had its abundance weakly influenced by the host weight. The other helminths were not influenced by biometric characteristics of the hosts. The total species richness was similar between male and female fish, and both had 14 helminth species of parasites.

Helminth fauna of Rhinella fernandezae (Anura: Bufonidae) from the Rio Grande do Sul coastland, Brazil: analysis of the parasite community.

Ninety specimens of Rhinella fernandezae , collected in Imbé, State of Rio Grande do Sul, Brazil, from August 2006 to April 2007, were examined for presence of helminth parasites; all were infected by at least 1 species. Thirteen species of parasites were found: 4 digeneans, 2 cestodes, 2 acanthocephalans, and 5 nematodes. Rhinella fernandezae represents a new host record, as well as for Gorgoderina festoni , Cylindrotaenia americana , Acanthocephalus lutzi , Aplectana meridionalis , and Strongyloides carinii . The nematodes Cosmocerca parva and A. meridionalis occurred with a prevalence of 79.1%, and, as in other Rhinella species, the nematodes dominated the parasite community. Host gender had no influence on either abundance or prevalence of the helminths, and neither the length nor weight of the hosts influenced the richness of the parasitic helminths of these burrowing toads. Only A. meridionalis and Centrorhynchus sp. (both cystacanths) exhibited a significant correlation between host length and abundance of helminths; only A. meridionalis showed a relationship between host length and prevalence.

Fimbriaria fasciolaris and Cloacotaenia megalops (Eucestoda, Hymenolepididae), cestodes from Brazilian waterfowl.

Two cestode species, Fimbriaria fasciolaris (Pallas, 1781) Frölich, 1802 Cloacotaenia megalops (Nitzsch in Creplin, 1829) Wolffhügel, 1938 collected from Anas bahamensis Linné, 1758 and Amazonetta brasiliensis (Gmelin, 1758) in lagoons of the Maricá District, State of Rio de Janeiro, Brazil, are described. This is the first record of F. fasciolaris parasitizing A. bahamensis. The prevalence, intensity of infection, and mean intensity of infection for both species are given. Overdispersion distribution is reported for F. fasciolaris with 535 specimens collected in a single A. bahamensis. A key for the genera in the Fimbriariinae is presented. Anatomical features of F. fasciolaris and C. megalops are discussed.

Eurytrema coelomaticum: influence of the infection on the reproduction and nucleic acids contents in the albumen gland and ovotestis of Bradybaena similaris.

The number of eggs laid per snail in Bradybaena similaris and the nucleic acids (DNA and RNA) in the albumen gland and ovotestis were quantified in snails infected with sporocysts of the digenetic trematode Eurytrema coelomaticum. The total number of eggs laid per mollusc was reduced by 96.32% at the end of the larval development. The DNA concentration increased by 700%, and the RNA concentration was reduced by 8.38% by the time when the daughter sporocysts of E. coelomaticum were released from B. similaris. The relation between these values and the inhibition of the reproduction observed in infected molluscs is discussed.

[Natural parasitism of Bradybaena similaris (Férussac, 1821) by Postharmostum gallinum Witenberg, 1923]. / Parasitismo natural de Bradybaena similaris (férussac, 1821) por postharmostomum gallinum witenberg, 1923.

A total of 4,298 snails Bradybaena similaris were collected from the rural area of Rio de Janeiro County and from the Counties of Paracambi and Itaguai, State of Rio de Janeiro. Two thousand and five of these snails had metacercariae in their pericardial cavity. The collecting was done between October 1983 and September 1986. The annual average prevalences were: 42.89% (1st year), 43.42% (2nd year) and 55.86% (3rd year). Experimental infection in chicks allowed the identification of these metacercariae as Postharmostomum gallinum. The small variation in size observed among metacercariae from the same host indicates that recruitment does not occur on a continuous basis. Statistical analysis showed no correlation between the snail size and the number of metacercariae in the pericardical cavity, and that the snail mortality observed in the laboratory was due to the parasitic infection.

Epidemiology of Fasciola hepatica infection in the Paraíba River Valley, São Paulo, Brasil.

The study revealed that although Lymnaea columella and Stenophysa marmorata were found in the same habitat, only L. columella harbored intramolluscan stages of F. hepatica. The population density of L. columella cyclically decreased between September and February, and increased from March to September. The drought that occurred between June and November 1981 dramatically reduced the number of snails collected. Larger snails were collected in March-July and November-December, while the smaller snails were collected in January-February and August-October, suggesting that there may be two generations of L. columella per year. The highest prevalence levels of infection in L. columella were: first year, June 8.82%, September 9.09% and October 10.52%; second year, March 6.25% and April 6.89%; third year, July 7.69%, August 10.25%, April 17.91% and May 13.91%. Results obtained with tracer sheep showed that the largest numbers of metacercariae were on pasture between June and October, and between March and April, but the infection was present during most of the year.

Infeccoes conjuntas de bovinos por Balanorchis anastrophus Fischoeder, 1901 e Paramphistomum sp. (Trematoda, Paramphistomidae) no Rio Grande do Sul, Brasil. / Cattle associated infections by Balanorchis anastrophus Fischoeder, 1901 and Paramphistomum sp. (Trematoda, Paramphistomidae) in Rio Grande do Sul, Brazil

Duzentos e noventa e seis bovinos (Bostaurus. L.) provenientes dos municipios de Santa Vitoria do Palmar (255), Pedro Osorio (27), e Camaqua (14), no Estado do Rio Grande do Sul, Brasil, foram examinados com o objetivo de encontrar termatodeos de rumen, A prevalencia dos trematodeos foi de aproximadamente 68, 70 e 100%, respectivamente. Balanorchis anastrophus foi encontrado em infeccoes conjuntas com Paramphistomum sp., em tres bovinos, entre os dez primeiros animais positivos para trematodeos, um de cada municipio. As infrapopulacoes de B. anastrophus foram encontradas com baixas densidades: 15 (3,56%), 4 (1,48%) e 27 (5,55%), enquanto aquelas de Paramphistomum sp. ocorreram em densidades maiores: 421, 270 e 486, respectivamente. Um metodo simples foi descrito, para a separacao de helmintos nao comprimidos e nao corados, dos generos Paramphistomum e Balanorchis. Os autores sugeriram que o mesmo podera ser util ao veterinario de campo e aos pesquisadores interessados em levantamentos de trematodeos de rumen em matadouros