Alterations in the metabolism of Pseudosuccinea columella (Mollusca: Gastropoda) caused by Heterorhabditis bacteriophora HP88 (Rhabditida: Heterorhabditidae)

The gastropod Pseudosuccinea columella participates in the dissemination of Fasciola hepatica in the environment, acting as the main intermediate host of this parasite in Brazil. The present study sought to elucidate the possible pathogenic effects of the entomopathogenic nematode (EPN) Heterorhabditis bacteriophora on P. columella, by evaluating the influence of infection on alanine aminotransferase (ALT) and aspartate aminotransferase (AST), as well as the concentrations of total protein, uric acid, and urea in the snail's hemolymph. For this, the snails were exposed to EPNs for 24 and 48 h, and for each exposure time, 20 snails were dissected after 7, 14 and 21 days for hemolymph collection. The primary findings suggest a significant proteolysis alongside elevated levels of uric acid and urea in P. columella infected individuals. These findings reveal that H. bacteriophora HP88 infection induced serious changes in the snail's metabolism, triggering important deleterious effects.

Influence of exposure Heterorhabditis bacteriophora HP88, (Rhabditida: Heterorhabditidae) on biological and physiological parameters of Pseudosuccinea columella (Basommatophora: Lymnaeidae)

Many studies about fasciolosis control have been carried out, whether acting on the adult parasite or in Pseudosuccinea columella, compromising the development of the larval stages. The present study aimed to evaluate, under laboratory conditions, the susceptibility of P. columella to Heterorhabditis bacteriophora HP88, during for 24 and 48 hours of exposure. The snails were evaluated for 21 days for accumulated mortality; number of eggs laid; hatchability rate; biochemical changes; and histopathological analysis. We found that exposure induced a reduction in glucose and glycogen levels, characterizing a negative energy balance, due to the depletion of energy reserves as a result of the direct competition established by the nematode/endosymbiont bacteria complex in such substrates. A mortality rate of 48.25% and 65.52% was observed in the group exposed for 24 h and 48 h, respectively, along with significant impairment of reproductive biology in both exposed groups in relation to the respective controls. The results presented here show that P. columella is susceptible to the nematode H. bacteriophora, with the potential to be used as an alternative bioagent in the control of this mollusk, especially in areas considered endemic for fascioliasis, in line with the position expressed by the World Health Organization Health.

Eurytrematosis in cattle in southern Espírito Santo State, Brazil - case report

This work reports an outbreak of eurytrematosis in cattle in the municipality of Ibitirama, southern Espírito Santo State, Brazil. Six cattle were necropsied from August to December 2019, with finding of Eurytrema coelomaticum in the pancreas. A survey of epidemiological data was carried out on the farms along with coproparasitological examination of cattle from the same herd. Parasites were found in all necropsied animals, with different degrees of parasitism, ranging from mild to massive infection (6 - 2000 specimens). Macroscopic analyses of the pancreas revealed changes in 83.33% (5/6) of the cases, and by microscopy, pancreatic fibrosis ranging from Grade I to Grade III was observed. Inspection of the grazing areas confirmed the presence of two intermediate hosts, a terrestrial snail of the Bradybaena genus, with larval forms of the trematode in histological findings, and a grasshopper of the Conocephalus genus. Although none of the cattle showed clinical signs in the coproparasitological examination, 73.80% (31/42) tested positive for E. coelomaticum eggs. This is the first record of an outbreak of eurytrematosis in cattle in Espírito Santo State, indicating the importance of carrying out diagnosis based on epidemiology and necroscopic and parasitological examinations in animals in the region so that appropriate control measures can be adopted.

Identificação e diferenciação morfológica de microfilárias no sangue de cães do Espírito Santo

As filarioses são helmintoses comuns em cães domésticos, podendo também ocorrer em gatos, cavalos e alguns animais selvagens. As espécies envolvidas com o parasitismo levam o hospedeiro a um quadro de microfilaremia, com produção de microfilárias que são muito semelhantes entre si, dificultando o diagnóstico. O objetivo deste trabalho foi esclarecer as diferenças morfológicas entre as microfilárias dos principais filarídeos de cães, em especial Dirofilaria immitis e Acanthocheilonema reconditum. Para este estudo, amostras sanguíneas de cães do Espírito Santo foram recolhidas por laboratórios veterinários, diagnosticadas previamente como positivas por meio do esfregaço sanguíneo e encaminhadas ao Laboratório de Parasitologia do Hospital Veterinário da Universidade Federal do Espírito Santo. As amostras foram submetidas ao teste de Knott modificado e avaliadas em lâmina sob microscópio óptico para caracterização morfométrica, com base nas características morfológicas da cabeça e cauda e posterior diferenciação das espécies de microfilárias encontradas. Setenta e duas amostras foram avaliadas, sendo que 69,44% representaram infecção por D. immitis e 15,27% por A. reconditum, sendo que, destas, 12,5% equivaleram à infecção simultânea entre as duas espécies. Não foram encontradas evidências que sugerissem outras espécies de filarídeos.