Effects of Immunization with Recombinant Schistosoma mansoni Enzymes AK and HGPRT: Murine Infection Control.

Schistosomiasis is one of the most important human helminthiases worldwide. Praziquantel is the current treatment, and no vaccine is available until the present. Thus, the presented study aimed to evaluate the immunization effects with recombinant Schistosoma mansoni enzymes: Adenosine Kinase (AK) and Hypoxanthine-Guanine Phosphoribosyltransferase (HGPRT), as well as a MIX of the two enzymes. Female Balb/c mice were immunized in three doses, and 15 days after the last immunization, animals were infected with S. mansoni. Our results showed that the group MIX presented a reduction in the eggs in feces by 30.74% and 29%, respectively, in the adult worms. The groups AK, HGPRT and MIX could produce IgG1 antibodies, and the groups AK and MIX produced IgE antibodies anti-enzymes and anti-S. mansoni total proteins. The groups AK, HGPRT and MIX induced a reduction in the eosinophils in the peritoneal cavity. Besides, the group AK showed a decrease in the number of hepatic granulomas (41.81%) and the eggs present in the liver (42.30%). Therefore, it suggests that immunization with these enzymes can contribute to schistosomiasis control, as well as help to modulate experimental infection inducing a reduction of physiopathology in the disease.

In vitro schistosomicidal activity of tamoxifen and its effectiveness in a murine model of schistosomiasis at a single dose.

Schistosomiasis is a neglected tropical disease affecting 220 million people worldwide. Praziquantel has proven to be effective against this parasitic disease, though there are increasing concerns regarding tolerance/resistance that calls for new drugs. Repurposing already existing and well-known drugs has been a desirable approach since it reduces time, costs, and ethical concerns. The anti-cancer drug tamoxifen (TAM) has been used worldwide for several decades to treat and prevent breast cancer. Previous reports stated that TAM affects Schistosoma hormonal physiology; however, no controlled schistosomicidal in vivo assays have been conducted. In this work, we evaluated the effect of TAM on female and male Schistosoma mansoni morphology, motility, and egg production. We further assessed worm survival and egg production in S. mansoni-infected mice. TAM induced morphological alterations in male and female parasites, as well as in eggs in vitro. Furthermore, in our in vivo experiments, one single dose of intraperitoneal TAM citrate reduced the total worm burden by 73% and led to a decrease in the amount of eggs in feces and low percentages of immature eggs in the small intestine wall. Eggs obtained from TAM citrate-treated mice were reduced in size and presented hyper-vacuolated structures. Our results suggest that TAM may be repurposed as a therapeutic alternative against S. mansoni infections.

Epiisopilosine alkaloid has activity against Schistosoma mansoni in mice without acute toxicity.

Schistosomiasis is a disease caused by parasites of the genus Schistosoma, currently affecting more than 200 million people. Among the various species of this parasite that infect humans, S. mansoni is the most common. Pharmacological treatment is limited to the use of a single drug, praziquantel (PZQ), despite reports of parasite resistance and low efficacy. It is therefore necessary to investigate new potential schistosomicidal compounds. In this study, we tested the efficacy of epiisopilosine (EPIIS) in a murine model of schistosomiasis. A single dose of EPIIS (100 or 400 mg/kg) administered orally to mice infected with adult S. mansoni resulted in reduced worm burden and egg production. The treatment with the lower dose of EPIIS (100 mg/kg) significantly reduced total worm burden by 60.61% (P < 0.001), as well as decreasing hepatosplenomegaly and egg excretion. Scanning electron microscopy revealed morphological changes in the worm tegument after treatment. Despite good activity of EPIIS in adult S. mansoni, oral treatment with single dose of EPIIS 100 mg/kg had only moderate effects in mice infected with juvenile S. mansoni. In addition, we performed cytotoxicity and toxicological studies with EPIIS and found no in vitro cytotoxicity (in HaCaT, and NIH-3T3 cells) at a concentration of 512 µg/mL. We also performed in silico analysis of toxicological properties and showed that EPIIS had low predicted toxicity. To confirm this, we investigated systemic acute toxicity in vivo by orally administering a 2000 mg/kg dose to Swiss mice. Treated mice showed no significant changes in hematological, biochemical, or histological parameters compared to non-treated animals. Epiisopilosine showed potential as a schistosomicidal drug: it did not cause acute toxicity and it displayed an acceptable safety profile in the animal model.

Anti-Inflammatory Properties of Menthol and Menthone in Schistosoma mansoni Infection.

Schistosomiasis is a parasitic disease caused by several species of trematode worms and it is believed that more than 261 million people are affected worldwide. New drug development has become essential because there is a risk of the parasite becoming resistant to Praziquantel, the only drug available for this infection. This study evaluated parasitological, immunological and histological parameters in mice infected with Schistosoma mansoni and treated with an herbal commercial medicine. This drug consists of menthol (30-55%) and menthone (14-32%). A 60 day treatment regimen with the herbal medicine decreased the number of S. mansoni eggs in the feces, liver, and intestine and reduced the number of hepatic granulomas. We observed a reduction of 84% in blood eosinophilia and a decrease in the IL-4 and IL-10 blood levels after treatment. Therefore, we propose that schistosomiasis treatment with this herbal medicine for 60 days has an immunomodulatory and anti-inflammatory action in this animal model for schistosomiasis thus contributing to the decrease in physio pathological effects caused by S. mansoni infection.

Nanostructured Lipid Carriers as a Strategy to Improve the In Vitro Schistosomiasis Activity of Praziquantel.

Praziquantel (PZQ) is a pyrazinoisoquinoline anthelmintic that was discovered in 1972 by Bayer Germany. Currently, due to its efficacy, PZQ is the drug of choice against all species of Schistosoma. Although widely used, PZQ exhibits low and erratic bioavailability because of its poor water solubility. Nanostructured lipid carriers (NLC), second-generation solid lipid nanoparticles, were developed in the 1990s to improve the bioavailability of poorly water soluble drugs. The aim of this study was to investigate nanostructured lipid carriers as a strategy to improve the efficacy of PZQ in S. mansoni treatment. We prepared NLC2 and NLC4 by adding seventy percent glycerol monostearate (GMS) as the solid lipid, 30% oleic acid (OA) as the liquid lipid and two surfactant systems containing either soybean phosphatidylcholine/poloxamer (PC/P-407) or phosphatidylcholine/Tween 60 (PC/T60), respectively. The carriers were characterized by nuclear magnetic resonance, differential scanning calorimetry, thermogravimetric analysis and Fourier transform-infrared spectroscopy. The safety profile was evaluated using red cell hemolysis and in vitro cytotoxicity assays. The results showed that the encapsulation of PZQ in NLC2 or NLC4 improved the safety profile of the drug. Treatment efficacy was evaluated on the S. mansoni BH strain. PZQ-NLC2 and PZQ-NLC4 demonstrated an improved efficacy in comparison with free PZQ. The results showed that the intestinal transport of free PZQ and PZQ-NLC2 was similar. However, we observed that the concentration of PZQ absorbed was smaller when PZQ was loaded in NLC4. The difference between the amounts of absorbed PZQ could indicate that the presence of T60 in the nanoparticles (NLC4) increased the rigid lipid matrix, prolonging release of the drug. Both systems showed considerable in vitro activity against S. mansoni, suggesting that these systems may be a promising platform for the administration of PZQ for treating schistosomiasis.

Anthelmintic activity in vivo of epiisopiloturine against juvenile and adult worms of Schistosoma mansoni.

Schistosomiasis is a serious disease currently estimated to affect more that 207 million people worldwide. Due to the intensive use of praziquantel, there is increasing concern about the development of drug-resistant strains. Therefore, it is necessary to search for and investigate new potential schistosomicidal compounds. This work reports the in vivo effect of the alkaloid epiisopiloturine (EPI) against adults and juvenile worms of Schistosoma mansoni. EPI was first purified its thermal behavior and theoretical solubility parameters charaterised. In the experiment, mice were treated with EPI over the 21 days post-infection with the doses of 40 and 200 mg/kg, and 45 days post-infection with single doses of 40, 100 and 300 mg/kg. The treatment with EPI at 40 mg/kg was more effective in adult worms when compared with doses of 100 and 300 mg/kg. The treatment with 40 mg/kg in adult worms reduced parasite burden significantly, lead to reduction in hepatosplenomegaly, reduced the egg burden in faeces, and decreased granuloma diameter. Scanning electron microscopy revealed morphological changes to the parasite tegument after treatment, including the loss of important features. Additionally, the in vivo treatment against juvenile with 40 mg/kg showed a reduction of the total worm burden of 50.2%. Histopathological studies were performed on liver, spleen, lung, kidney and brain and EPI was shown to have a DL50 of 8000 mg/kg. Therefore EPI shows potential to be used in schistosomiasis treatment. This is the first time that schistosomicidal in vivo activity of EPI has been reported.

Field study on the efficacy of an oral 2% ivermectin formulation in horses / Eficácia a campo de uma formulação oral de ivermectina a 2% em equinos

Twenty horses naturally infected with nematodes were included in a blind, controlled field study on efficacy and safety of an oral 2% ivermectin formulation at a dose of 0.2 mg.kg–1. Horses were divided into treated and non-treated (control) groups with ten animals each based on preliminary counts of eggs per gram of feces (EPG). Stool samples were collected after treatment for identification of nematode species. Clinical evaluations and EPG counts were performed on days 0, +5, +14 and +19. Nineteen nematode species were identified: Coronocyclus ulambajari, Craterostomum acuticaudatum, Cyathostomum catinatum, Cyathostomum pateratum, Cylicocyclus brevicapsulatus, Cylicocyclus insigne, Cylicocyclus leptostomum, Cylicocyclus nassatus, Cylicocyclus ultrajectinus, Cylicocyclus spp., Cylicostephanus calicatus, Cylicostephanus longibursatus, Cylicostephanus poculatus, Habronema muscae, Habronema spp., Parascaris equorum, Poteriostomum imparidentatum, Oxyuris equi and Triodontophorus spp. The mean EPG counts of treated and non-treated (control) groups on Days –15, 0, +5, +14 and +19 were 1925, 1340, 0, 12.5, 0, 1470, 790, 875, 1605 and 1240 respectively. The efficacy of treatment on Days +5, +14 and +19 was 100, 99.2 and 100% respectively, with a significant difference compared to the control group (p < 0.01). The product was considered to be safe with no findings of clinical significant changes during the study.

Vinte equinos naturalmente infectados com nematódeos foram utilizados em estudo cego, controlado, de eficácia e segurança clínica a campo de uma formulação oral de ivermectina a 2%, na dosagem de 0,2 mg.kg–1. Foram distribuídos em grupos: tratado e sem tratamento, de dez animais cada, baseados na contagem prévia de ovos por grama de fezes (OPG). Amostras de fezes foram colhidas pós-tratamento para identificação da helmintofauna. Avaliações clínicas e OPG foram realizados nos dias 0, +5, +14 e +19. Identificou-se dezenove espécies de nematódeos: Coronocyclus ulambajari, Craterostomum acuticaudatum, Cyathostomum catinatum, Cyathostomum pateratum, Cylicocyclus brevicapsulatus, Cylicocyclus insigne, Cylicocyclus leptostomum, Cylicocyclus nassatus, Cylicocyclus ultrajectinus, Cylicocyclus spp., Cylicostephanus calicatus, Cylicostephanus longibursatus, Cylicostephanus poculatus, Habronema muscae, Habronema spp., Parascaris equorum, Poteriostomum imparidentatum, Oxyuris equi e Triodontophorus spp.. As contagens médias de OPG dos grupos tratado e controle nos dias -15, 0, +5, +14 e +19 foram respectivamente 1925, 1340, 0, 12,5, 0 e 1470, 790, 875, 1605 e 1240. A eficácia do produto nos dias +5, +14 e +19 foi respectivamente de 100, 99,2 e 100%, com diferença significativa em relação ao grupo controle (p < 0,01). O produto mostrou-se seguro, não sendo observadas alterações clínicas dignas de nota durante o experimento.

Occurrence of Microcerella halli (Engel) (Diptera, Sarcophagidae) in snake carrion in southeastern Brazil / Ocorrência de Microcerella halli (Engel) (Diptera, Sarcophagidae) em uma Carcaça de Cobra no Sudeste Brasileiro

The occurrence of 27 second-instar larvae of the flesh fly Microcerella halli (Engel, 1931) (Diptera, Sarcophagidae) in a carcass of a snake usually called as Urutu, Bothrops alternatus (Duméril, Bibron & Duméril, 1854) (Serpentes, Viperidae, Crotalinae) is reported. The snake was kept in captivity in a snake farm in Morungaba, São Paulo state, Brazil. Descriptions of reptile carcass colonization by insects and general biological data of this flesh fly are scarce and this necrophagic behavior is described for the first time in literature.

A ocorrência de 27 larvas de segundo estádio do sarcofagídeo Microcerella halli (Engel, 1931) (Diptera, Sarcophagidae) em uma carcaça de urutu Bothrops alternatus (Duméril, Bibron & Duméril, 1854) (Serpentes, Viperidae, Crotalinae) é relatada. A cobra era mantida em cativeiro em um serpentário no município de Morungaba, estado de São Paulo, Brasil. Descrições de colonização de carcaças de répteis por insetos e dados gerais da biologia deste sarcofagídeo são escassos, e este comportamento necrófago é descrito pela primeira vez na literatura.