Glucantime™ is the pentavalent antimony (Sb+5) recommended as the first choice for treating cutaneous leishmaniasis (CL). It has been used as treatment control in animal studies to investigate new ...anti-Leishmania compounds. However, these studies have a range of Glucantime™ doses, different treatment times and routes of administration, and differing results. Our goal was to standardize intraperitoneal Glucantime™ treatment for CL in BALB/c mice infected with L. amazonensis. BALB/c mice were divided into six groups, with eight animals per group. The animals were infected with L. amazonensis and intraperitoneally treated with different doses of Sb+5 (20, 100 and 200 mg/kg/day) for 30 consecutive days. Healthy animals were used as negative infection and treatment control. Infected and untreated animals were used as positive infection control. Animals infected and treated with Ampho B were used as treatment control. Biochemical and histological analysis was performed to assess renal and liver toxicity. The parasite load in the popliteal lymph node, spleen and liver was determined by limiting dilution. Histological and collagen fiber analyses were performed on the lesions. Animals treated with Sb+5 100 and 200 mg/kg/day showed a decreased paw measurements, associated with a reduction in the parasite load, with a clinical cure rate of 50% and 37.5%, respectively. These groups of animals also showed tissue regeneration and reduced inflammation. Animals treated with 100 mg/kg/day had collagen fiber parameters similar to those of the negative infection control. There were no biochemical signs of renal or liver toxicity in any of the groups. We found that Sb+5 100 mg/kg/day was the lowest dose that showed effectiveness in treating CL in mice, and it may be a good model of treatment control in studies evaluating new treatments for CL in BALB/c mice.
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•Glucantime™ (Sb+5 100 mg/kg/day) effectively treated CL in BALB/c mice.•It showed a good cure rate, reduced parasite load, and tissue reconstitution.
Copro-microscopic diagnostic methods are the most common approach for screening patients with parasitic infections. However, expertise is required to identify helminthic eggs from fecal specimens. ...Consequently, new methods are required to support accurate species identification. Novel technologies have recently been developed for the classification of organisms, including geometric morphometric (GM) approaches. In this study, the outline-based GM approach was used to distinguish the eggs of 12 common human parasite species, including Ascaris lumbricoides, Trichuris trichiura, Enterobius vermicularis, hookworm, Capillaria philippinensis, Opisthorchis spp., Fasciola spp., Paragonimus spp., Schistosoma mekongi, Taenia spp., Hymenolepis diminuta and Hymenolepis nana. The GM analysis revealed that the size cannot be used as the main variable in the identification of parasite species at the egg stage, producing only 30.18% overall accuracy. However, comparisons of shape based on the Mahalanobis distances between pairs of parasite species showed significant differences in all pairs (p < 0.05). The shape analysis produced 84.29% overall accuracy. This is the first time that outline-based GM has been preliminarily confirmed as a valuable approach to support copro-microscopic analysis, in order to effectively screen helminth eggs. However, further studies with a larger set of helminth eggs and artefacts should be carried out to increase confidence in the identification of parasite species in the absence of local experts.
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•This study is the first geometric morphometric experiment with human parasite eggs.•The comparisons of shape parasite eggs showed significant differences in all pairs.•Our finding demonstrated that outline-based GM analysis could be applied to the identification of parasites in the egg stage.
Neospora caninum is an obligate intracellular parasite related to abortion in cattle, goats and sheep. The life cycle of N. caninum is characterized by the time-coordinated secretion of proteins ...contained in micronemes, rhoptries and dense granules, allowing the active invasion and the adaptation of the parasite in the cell environment. Thus, the proteins of the secretome have the potential to be considered as targets for N. caninum control. Despite the importance of neosporosis in the livestock-related economy, no commercial treatment is available. Furthermore, the process of invasion, propagation and immune evasion are not completely elucidated. In this study, we initiated the characterization of NCLIV_011700 of N. caninum, a protein with low sequence identity to NcROP15 or TgROP15 (<15%). Our goal was the detection and molecular characterization of the NCLIV_011700, once homology (with low identity >20%) was observed within the Apicomplexa. The NCLIV_011700 sequence was aligned and compared to the closer apicomplexan homologues (ROP15 from N. caninum, T. gondii, Hammondia hammondi, Cystospores suis), including the predicted domains. In general, the NCLIV_011700 demonstrated low identity with ROP15 of apicomplexan (<20%) and had a ubiquitin domain. On the other side, the NCLIV_011700 homologues were composed of a non-cytoplasmic domain, suggesting different functions between NcROP15 (or homologues) and NCLIV_011700 during the parasite life cycle. Moreover, the NCLIV_011700 was amplified by PCR, ligated to a pET28a plasmid and expressed in Escherichia coli. The recombinant form of NCLIV_011700 was purified in a nickel-Sepharose resin and applied for polyclonal antibody production in mice. The antiserum against NCLIV_011700 (anti-rNCLIV_011700) was used to localize the native form of the protein using Western blot and confocal microscopy. Also, the NCLIV_011700 antiserum partially inhibited the parasite adhesion/invasion process, indicating an active role of the protein in the N. caninum cycle. Thus, the initial NCLIV_011700 characterization will contribute to enlarging the comprehension of N. caninum, aiming at the future development of tools to control the parasite infection/propagation.
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•NCLIV_011700 is a Neospora caninum protein with no homologue in Toxoplasma gondii.•NCLIV_011700 has a low identity (<20%) with Apicomplexan rhoptries's proteins (ROP15s).•NCLIV_011700 has a Ubiquitin domain, whereas NcROP15 and TgROP15 are composed of a non-cytoplasmic domain.•The NCLIV_011700 protein was detected in the nuclear region of the tachyzoites, with 32.4 kDa.•The NCLIV_011700 antiserum partially inhibited (18%) the process of adhesion/invasion of tachyzoites in Vero cells.
Resistance of Haemonchus contortus to ivermectin has become an increasingly serious problem worldwide. Drug-based control and management of this parasite requires reliable methods for testing drug ...resistance to evaluate and monitor their anthelmintic effects. In this study, the larval migration inhibition test (LMIT) and the larval feeding inhibition test (LFIT) were used to assess and compare seven strains of H. contortus, including one resistant and one susceptible strain from abroad (UKR and ASS, respectively), and five strains native to China (SXS, WMR, WSR1, WSR2, and WSR3). LFIT results showed that fluorescent-labeled Escherichia coli could be clearly observed after ivermectin (IVM) treatment inside UKR, WMR, WSR1, WSR2, and WSR3 larvae, but not inside ASS and SXS strains. Moreover, LMIT results showed that migration of SXS strain did not change significantly after IVM treatment compared with the susceptible ASS strain, whereas migration increased significantly in the UKR, WMR, WSR1, WSR2, and WSR3 strains. Taken together, SXS was found to be an IVM-susceptible strain, whereas WMR, WSR1, WSR2, and WSR3 were IVM-resistant strains. These results demonstrate that assessment of the motility and feeding ability of H. contortus larvae can be effectively used to determine resistance of H. contortus to IVM.
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•Motility and feeding assessment revealed IVM-resistance status of the strains.•SXS strain was identified as IVM-sensitive, whereas the others were IVM-resistant.•The data further supported for the in vitro detecting of anthelmintic resistance.
Larval stages of taeniid Echinococcus granulosus are the infective forms of cystic echinococcosis or hydatidosis, a worldwide zoonosis. The protoscolex that develops into the adult form in the ...definitive host is enveloped by a complex cellular syncytial tegument, where all metabolic interchange takes place. Little information is available as to the electrical activity of the parasite in this developmental stage. To gain insight into the electrical activity of the parasite at the larval stage, we conducted microelectrode impalements of bovine lung protoscoleces (PSCs) of Echinococcus granulosus in standard saline solution. We observed two distinct intra-parasitic potentials, a transient peak potential, and a stable second potential, most likely representing tegumental and intra-parasitic extracellular space electrical potential differences. These values changed on the developmental status of the parasite, its anatomical regions, or time course after harvesting. Changes in electrical potential differences of the parasite provide an accessible and valuable parameter for the study of transport mechanisms and potential targets for developing novel antiparasitic therapeutics.
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•Tegumental electrical potentials were measured in protoscoleces of E. granulosus.•A negative transient deflection in electrical potential was always recorded.•This transient potential always spontaneously decayed to another lower potential.•Electrical recordings decreased through time post-harvesting.•Potentials were significantly higher in rostellum than the sucker and body regions.
To better control gastrointestinal nematode infections in humans and animals, it is important to understand the strategies used by these parasites to modulate the host immune system. In this regard, ...molecules released by parasites have been attributed crucially important roles in host-parasite negotiations. We characterized the excretory/secretory (E/S) microRNA (miRNA) and protein profiles from the mouse gastrointestinal nematode parasite Trichuris muris. Released miRNAs were subjected to miRNA sequencing and E/S proteins were analysed by mass spectrometry. Fourteen miRNAs were identified in T. muris exosome-like vesicles, as well as 73 proteins of nematode origin, 11 of which were unique to this study. Comparison with published nematode protein secretomes revealed high conservation at the functional level.
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•We characterized the microRNAs and proteins in vesicles released by Trichuris muris.•Fourteen miRNAs were identified in T. muris exosome-like vesicles.•We found 73 proteins of nematode origin, 11 of which were unique to this study.
Fasciola hepatica is a well-known helminth parasite, with significant economic and public health importance all over the world. It has been known since more than 630 years ago and a considerable ...research work has been carried out on the life cycle of this important parasite. In the hepatic phase of the life cycle of F. hepatica, it is assumed that the young flukes, after about 6–7 weeks of migration in the liver parenchyma, enter into the bile ducts of the definitive hosts and become sexually mature. Even though the secretion of cysteine peptidases including cathepsin L and B proteases by F. hepatica may justify this opinion, because of several scientific reasons and based on the experimental studies conducted in different animals (reviewed in this article), the entry of parasites into the bile ducts, after their migration in the liver parenchyma seems to be doubtful. However, considering all the facts relating to the hepatic and biliary phases of the life cycle of F. hepatica, two alternative ideas are suggested: 1) some of the migrating juvenile flukes may enter into the bile ducts immediately after reaching the liver parenchyma while they are still very small, or 2) when newly excysted juvenile flukes are penetrating into the intestinal wall to reach the liver through the abdominal cavity, a number of these flukes may enter into the choleduct and reach the hepatic bile ducts, where they mature.
According to the previously performed natural and experimental studies in different animals and human beings, the supporting and opposing evidences for the current opinion as well as the evidences that might justify the two new ideas are reviewed and discussed briefly. In conclusion, our present knowledge about the time and quality of the entry of F. hepaticas into the bile ducts, seems to be insufficient, therefore, there are still some dark corners and unknown aspects in this field that should be clarified.
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•The exact rout of Fasciola hepatica into the bile ducts is controversial.•It may enter the bile ducts through the choleduct, blood stream or abdominal cavity.•The exact time of the entry of the parasite into the bile ducts should be clarified.•The entry route of F. hepatica into the bile ducts should be histologically documented.•Initiative techniques such as radiolabeling assays may be used for the above purposes.
The acaricidal activity of combinations of thymol, carvacrol and eugenol was evaluated on larvae and engorged females of the cattle tick Rhipicephalus microplus. The first step assessed the compounds ...separately, in concentrations of 3.125, 6.25, 12.5 and 25 mg/mL. Then tests were performed with the compounds combined in the ratio of 1:1 at concentrations of 3.125 and 6.25 mg/mL, along with the control group treated with the solvent (3% DMSO). In the second step, combinations were tested incorporated in a formulation at the concentration de 6.25 mg/mL, using the larval packet and adult immersion tests. The associations carvacrol + thymol (3.125 mg/mL), carvacrol + eugenol and thymol + eugenol (6.25 mg/mL) presented synergism, while the other associations had an additive effect. In the experiments with formulation, all combinations caused 100% larval mortality, but the efficacy was under 15% against engorged females. Therefore, the combinations of thymol + carvacrol (3.125 mg/mL) as well as carvacrol + eugenol and eugenol + thymol (6.25 mg/mL) had a synergistic effect on engorged females, but when incorporated in the formulation, the acaricide activity was strong against larvae but weak against engorged females.
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•The associations showed a synergistic effect on R. microplus females.•The formulated associations showed high activity on R. microplus larvae.•The formulated associations showed low activity on R. microplus females.
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a rapid and reproducible method that has been widely applied for the identification of bacteria and ...fungi. However, this technique has not yet been applied in clinical laboratories for parasitology, such as for the study of the protozoan Leishmania.
By using MALDI-TOF MS, mass spectra database entries (MSPs) were created with 7 World Health Organization reference strains in order to establish a rapid method for Leishmania species identification. Furthermore, cluster analysis was performed with 18 Chinese Leishmania isolates.
The MSPs of Leishmania corresponded well with our past identification results, and the dendrogram analysis result was more or less similar to that of the phylogenetic analysis performed by multi-locus sequence typing.
MALDI-TOF MS is a promising method that offers both rapidity and efficiency for the identification and dendrogram analysis of Leishmania species.
1、 The MSPs of Leishmania corresponded well with our past identification results2、 The dendrogram analysis result was more or less similar to that of the phylogenetic analysis performed by multi-locus sequence typing3、 MALDI-TOF MS is a promising method that offers both rapidity and efficiency for the identification and dendrogram analysis of Leishmania species. Display omitted
•Leishmaniasis is still common in many Neglected tropical diseases, which underlines the fact that rapid identification and easy phylogenetic analysis for Leishmania have clinical and epidemiology value to guide prevention and treatment. In this work, we evaluated the identification performance of matrix-assisted laser desorption ionization-time of flight mass spectrometry for Leishmania and we also find out that this method is helpful in dendrogram analysis.
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