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.

Physiological alterations in Pseudosuccinea columella (Mollusca: Gastropoda) after infection by Heterorhabditis baujardi LPP7 (Rhabditida: Heterorhabditidae)

The snail Pseudosuccinea columella participates in the distribution of Fasciola hepatica in the environment by acting as its intermediate host. Therefore, the control of this lymnaeid is one of the ways to prevent hepatic fascioliasis. The objective of this study was to evaluate the susceptibility of P. columella to infective juveniles (IJs) of the entomopathogenic nematode (EPN) Heterorhabditis baujardi in laboratory conditions, as well as to investigate aspects related to the biochemistry and histopathology of snails exposed or not to the EPNs during three weeks. The EPN exposure induced significant reductions in the concentrations of glucose, total proteins and glycogen (gonad-digestive gland complex) in the snails during the onset of the infection, with the levels being restored as the infection progresses. These alterations were accompanied by increased hemolymph activities of aminotransferases and lactate dehydrogenase, as well as the concentrations of uric acid after the first and second weeks of the experiment. The histopathological analyses of the exposed snails revealed cell necrosis at the end of the first week, tissue inflammatory reactions one and two weeks after exposure, and degeneration three weeks afterward in comparison with the unexposed snails. Finally, scanning electronic microscopy revealed proliferation of fibrous connective tissue three weeks after exposure. The results indicate that P. columella is susceptible to H. baujardi. The exposure favored the establishment of a negative energy balance, increased the activity of enzymes related to tissue damages and promoted accumulation of nitrogen compounds in the host snails. Additionally, was observed in P. columella exposed to the EPNs, significant tissue lesions, and demonstrated the strong pathogenic potential of H. baujardi, indicating its possible application for biological control of this snail.

Rare case of Dioctophyme renale (Nematoda: Enoplida) and Dirofilaria sp. (Nematoda: Spirurida) in the subcutaneous tissue of a cat in Espírito Santo, Brazil

Dioctophyme renale is the largest parasitic nematode of animals. It is most often found in the right kidney, but can also occur in the urinary system, ears, free abdominal cavity, mammary gland, thoracic cavity, and more rarely in subcutaneous tissue. The genus Dirofilaria has specific parasitic characteristics according to its location, and may parasitize the respiratory tract or even the skin, varying according to species. This report describes a case of Dioctophyme renale and Dirofilaria sp. in the subcutaneous tissue of a cat in the state of Espírito Santo, Brazil. An adult male mongrel cat showed physical enlargement in the left inguinal region, diagnosed as a subcutaneous nodule. Surgical excision and histopathological evaluation of the nodule were performed, and Dioctophyme renale and Dirofilaria sp. were found inside. Dioctophymosis and heartworm disease are present in Brazil and most other countries, but this is the unprecedented case of the association of Dioctophyme renale and Dirofilaria sp. in the subcutaneous tissue of a cat.

Association of radioactivity of the monazite sands of the beaches of the Guarapari city with the presence of parasites of zoonotic potential

The city of Guarapari, known as "Healthy City", has as its main tourist attraction radioactive sands known as monazite sands. There are many studies aimed at quantifying radiation, but little is known about an influence of radiation levels on the life cycle of parasites with zoonotic potential, since many owners take their animals to beaches facilitating a maintenance of their cycle. The objective of the present work was to evaluate the association of the sand radiation of the beaches of the municipality of Guarapari and the presence of eggs and larvae of zoonotic potential parasites. To determine the influence of the radiation on the parasites, sand and faeces samples were collected from the beaches of Praia do Morro, Areia Preta, Castanheiras, Setiba and Santa Mônica, and how to analyze, use the simple centrifugal-flotation technique. The beaches of the present study were classified as low, medium and high radioactivity according to the dose limits that a human being can receive. The samples of sand and faeces were grouped according to a classification of the beaches where they were collected as samples. After obtaining the result, a Chi-square statistical test was performed at a significance level of 95% to evaluate an association between radiation classes and parasite presence. In general, monazitic sands have an influence on the maintenance of the cycle of zoonotic parasites found in beach sand, their correlation being inversely proportional.