Ecology of Clinostomum complanatum Rudolphi, 1814 (Trematoda: Clinostomidae) infecting fish from the floodplain of the high Paraná River, Brazil.

The prevalence of Clinostomum complanatum Rudolphi, 1814 (Digenea, Clinostomidae) in fishes Loricariichthys platymetopon, Parauchenipterus galeatus and Hoplosternum littorale, which are second intermediate hosts, was studied at the floodplain of the high Paraná River, Brazil. Season (alternation flood-drought), habitat (lentic and semi-lotic), and sex were not related to its prevalence. For L. platymetopon, the immature and smaller fish had the lowest prevalence, whilst the opposite was observed for P. galeatus and H. littorale. This suggests that the probability of being predated is unchanged by parasitism for L. platymetopon; thus, a cumulative effect of repeated infections is observed; for the two other species, the highest parasitised fish may have higher predation mortality rates. While H. littorale is the preferred item in birds' diet, L. platymetopon is the most abundant fish species and has the highest C. complanatum prevalence, which makes it the most likely path of transmission to the bird, the definitive hosts of C. complanatum.

The life cycle of Clinostomum complanatum Rudolphi, 1814 (Digenea, Clinostomidae) on the floodplain of the high Paraná river, Brazil.

The life cycle of the digenetic trematode Clinostomum complanatum was studied on the floodplain of the high Paraná river, Brazil. Sampling was done between June 1999 and June 2000. The mollusc Biomphalaria peregrina was the first intermediate host with a prevalence of infection of 0.75%. The fish Loricariichthys platymetopon, Hoplosternum littorale, Parauchenipterus galeatus, Hoplias malabaricus and Loricaria sp. were second intermediate hosts, with the prevalence varying from 2.45% ( H. malabaricus) to 60.8% ( L. platymetopon). The birds Ardea cocoi, Phalacrocorax brasilianus, Egretta alba and Egretta thula were definitive hosts, with the prevalence ranging between 5.5% ( E. thula) and 95% ( A. cocoi). The high prevalences in birds, especially in A. cocoi, suggest some kind of mechanism facilitating the predation of infected fish. The importance of the various hosts is discussed, and it is concluded that the floodplain of the high Paraná river has suitable conditions for the maintenance of the life cycle of C. complanatum.

Frequência de parasitos intestinais em cães domiciliados da cidade de Maringá, PR / Frequency of intestinal parasites in domiciled dogs from Maringá city, Brazil

The frequency of eggs and cysts of intestinal parasites in domiciled dogs that lived in the city of Maringá, Brazil, was studied. From November 2006 to November 2007, stools of 81 dogs were examined, of which 44.4% were positive for some kind of enteric parasite. The most frequent was Ancylostoma spp. with 18.5% (15/81) followed by Giardia lamblia with 11.1% (9/81). There was association of parasites in 11.0% of the samples, being the most frequent Ancylostoma spp. and Trichuris vulpis (6.2%) (5/81). There were sources of contamination where the animals lived which were responsible for maintaining the parasite in the environment.