New more selective and potent drugs are urgently need to treat Chagas disease (CD). Among the many synthetic compounds evaluated against Trypanosoma cruzi, aromatic amidines (AAs) and especially arylimidamides (AIAs) have potent activity against this parasite. Presently, the effect of four mono-amidines (DB2228, DB2229, DB2292 and DB2294), four diamidines (DB2232, DB2235, DB2251 and DB2253) and one AIA (DB2255) was screened in vitro against different forms (bloodstream trypomastigotes – BT and intracellular forms) and strains from discrete typing unit (DTU) I and VI of T. cruzi and their cytotoxic profile on mammalian host cells. Except for DB2253, all molecules were as active as benznidazole (Bz), resulting in 50% of reduction in the number of alive BT, with EC50 ranging from 2·7 to 10·1 µm after 24 h of incubation. DB2255 was also the most potent against amastigotes (Tulahuen strain) showing similar activity to that of Bz (3 µm). In silico absorption, distribution, metabolism, excretion and toxicity analysis demonstrated probability of human intestinal adsorption, while mutagenicity and inhibition of hERG1 were not predicted, besides giving acceptable predicted volumes of distribution. Our findings contribute for better knowledge regarding the biological effect of this class of aromatic molecules against T. cruzi aiming to identify novel promising agent for CD therapy.

Haemosporidian parasites are widespread in avian species and modulate their ecology, behaviour, life-history and fitness. The prevalence of these vector-transmitted parasites varies with host intrinsic and extrinsic factors, such as host resistance and behaviour, and habitat-related characteristics. In this study, we evaluated the prevalence of avian haemosporidians in great tit Parus major populations inhabiting two areas with different degrees of exposure to aerial emissions from pulp mills, to assess if this type of pollution impacted parasite prevalence. We also compared the physiological condition of infected and uninfected individuals. Haemosporidian infection prevalence was high (58%), varied seasonally, but was not associated with air pollution exposure. Fledged birds presented higher infection rates than nestlings and infected fledged birds had higher levels of blood glutathione peroxidase activity. These results allow us to infer that infection by blood parasites may activate antioxidant defences, possibly to protect the organism from the negative oxidative stress side-effects of immune activation against parasites. Because oxidative stress is one of the mechanisms responsible for ageing and senescence and may affect fitness, the relationship between parasitism and oxidative stress markers should be further investigated through studies that include experimental manipulation of infection in model organisms.

We performed a cross-sectional survey in humans to evaluate Lutzomyia longipalpis, i.e. sand fly vector, bite exposure association with Leishmania (Leishmania) infantum chagasi infection in Bujarú municipality, Northern Brazil, an endemic area for visceral leishmaniasis. In recruited individuals, which were stratified by sex and age, we measured L. (L.) i. chagasi parasitic loads with quantitative polymerase chain reaction (qPCR), exposure to sand fly bites with an anti-saliva immunoglobulin G enzyme-linked immunosorbent assay and performed immunological diagnostic tests, in order to evaluate the association between exposure to sand fly bites, and infection. The prevalence increased from 11% when using immunological diagnostic tests to 28% when using qPCR, being around that value for all age classes, but children below 5 years (40%) and people over 60 years (15%). The association between PCR-based L. (L.) i. chagasi prevalence and saliva exposure was convex, reflecting the fact that at both high and low saliva exposure the PCR-based L. (L.) i. chagasi prevalence decreases. This scenario indicates that low sand fly exposure is likely associated with low parasite transmission, while high anti-saliva prevalence, i.e. a large sand fly bite exposure could be associated with anti-Leishmania protective immune mechanisms driven by vector saliva and/or increased parasite exposure.

Blastocystis sp. is a protozoan commonly found in human and animal stool samples. Several pathogenic and zoonotic aspects of this organism are still unknown. The aim of the present study was to investigate Blastocystis subtypes (STs) in samples from patients of the Hospital das Clínicas of the Faculdade de Medicina at the Universidade de São Paulo (HC-FMUSP), Brazil. Blastocystis sp.-positive stool samples diagnosed at the Section of Parasitology of the Central Laboratory (HC-FMUSP) were used for DNA isolation. Polymerase chain reaction (PCR) was performed using specific primers targeting the small-subunit rRNA gene. Direct DNA sequencing of the PCR products was performed and the DNA sequences were then aligned and compared with other sequences obtained from the GenBank database. Phylogenetic analysis was used to identify STs and determine the phylogenetic relationships between the sequences. Four STs were identified: ST1 (22·5%), ST2 (12·5%), ST3 (60%) and ST6 (5%). In conclusion, ST3 was the most prevalent ST among the human isolates followed by ST1. The present study is one of the few providing STs data from the human population in South America. Determining ST prevalence in human samples may contribute to the monitoring of Blastocystis sp. infection transmission in endemic regions.

Feline leishmaniasis has been reported in various parts of the world in recent years, occurring mainly in areas where zoonotic visceral leishmaniasis (VL) is endemic. The purpose of this study was to assess the occurrence of natural infection by Leishmania spp. in domestic cats (Felis catus) in the municipality of Teresina, Piauí state, Brazil, an endemic area of VL in Brazil. The prevalence of infection by Leishmania spp. in the population under study was 4% (3/83) in the enzyme-linked immunosorbent assay (ELISA) and 4% (3/83) by smear observation and isolation in a culture medium, using popliteal lymphnode sample. Only one of the three infected cats was positive for ELISA, also being positive for feline immunodeficiency virus. In the haematologic parameters, normocytic normochromic anaemia was the most common change, being present in the three infected animals. In the biochemical measurements also were observed alterations in infected animals. The Leishmania spp. strains isolated from the culture medium were characterized as L. infantum. The presence of L. infantum infection in cats in the city of Teresina, an area endemic for VL, suggests the possible involvement of these animals in the epidemiological chain of L. infantum in high-transmission areas.

This study is an attempt to unravel the infection pattern of the Caryophyllaeid tapeworm, Adenoscolex oreini and its association with water quality, planktonic copepods and health traits of fish in a highly stressed lake. Prevalence differed significantly (P < 0·05) among different fish species with highest infection recorded in Schizothorax niger (% = 36·74) compared to Schizothorax esocinus (% = 15·7). Within-lake trophic gradient affected the infection pattern as prevalence of A. oreini was significantly higher (44·62%, P = 0·0001) at hypereutrophic site as compared to least eutrophic site (8·01%). The data suggest that spatial variation in the intensity of A. oreini corresponded to the variation in the abundance of planktonic copepods. The density of Cyclops scutifer was positively correlated with the prevalence of tapeworm. Results indicate that the health condition, which was reflected by condition factor and gonadosomatic index, was lower in parasitized fish, and there seems to be synergistic effect of eutrophication and parasitism on fish health. Linear regression coefficients showed that the health indices were significantly (P < 0·05) predicted by infection intensity. It is concluded from the results that within-lake pollution gradient affects the infection pattern, density of intermediate host and health attributes of fish, and therefore these finding will lead us to elucidate the predictors responsible for decline of health of fish in highly stressed water bodies.

The female and nymph of Ixodes (Pholeoixodes) kangdingensis n. sp. are described based on both morphology and analysis of 16S rRNA gene sequences. Specimens of this new tick species were collected from a Siberian weasel (Mustela sibirica) in Kangding County, Sichuan Province, China. The morphological features of the female and nymph are unique to distinguish I. kangdingensis n. sp. from other members of the subgenus Pholeoixodes, including the presence of distinctly shaped cornua, anterior and posterior processes on palpal article I and a large angular projection on each side of the hypostome. Partial sequence of 16S rRNA gene grouped this species with Ixodes arboricola and Ixodes lividus with sequence divergence of new species from I. arboricola 4·16% and from I. lividus 8·49%. Data on the phylogenetic position, hosts, geographic distribution and key to females of closely related species are also provided.

A serological survey was performed to evaluate the presence of specific antibodies against Neospora caninum in dogs and native animals in a wildlife conservation area in southern Portugal. The study involved 463 animals, including dogs (n = 286), European rabbits (Oryctolagus cuniculus; n = 32), Egyptian mongoose (Herpestes ichneumon; n = 34), wild boars (Sus scrofa; n = 26), foxes (Vulpes vulpes, n = 25), common genets (Genetta genetta; n = 17), red deer (Cervus elaphus; n = 14), wildcats (Felis silvestris; n = 6), four mustelid species (n = 17) and rodents (n = 6). Samples from dogs were analysed by Indirect Fluorescent Antibody Test (IFAT). Samples from wild animals were screened by the modified agglutination test and positive and doubtful results were confirmed by IFAT. The seroprevalence of N. caninum in dogs was 32·5% [95% confidence interval (95% CI) 27·3–38·1]. Among wild animals, exposure to N. caninum was confirmed only in foxes (12%, 95% CI 4·2–30) and rabbits (25%, 95% CI 13·3–42·1). This is the first evidence of natural exposure to N. caninum in foxes and rabbits in Portugal, and our results suggest that rabbits may play a role as reservoirs of infection to dogs, foxes and other wildlife carnivores. The relevance of this finding in the sylvatic cycle of N. caninum needs further studies, since infection may affect wildlife species and cattle grazing in the same areas.

On 9 November 2015, a juvenile male fin whale of 11·60 m length was observed on the bulb of a merchant vessel in the Channel Terneuzen – Ghent (The Netherlands – Belgium). A severe parasitosis was present in the right heart ventricle and caudal caval vein. Parasites were identified as Crassicauda boopis based on macroscopic and microscopic observations. The sequence of the 18S rRNA gene obtained from the parasite samples was 100% similar to the sequence of the 18S rRNA gene from Crassicauda magna available on GenBank. While adults of C. boopis and C. magna are morphologically distinct and found at different locations in the body, the molecular analysis of the 18S rRNA gene seems insufficient for reliable species identification. Although numerous C. boopis were found, the cause of death was identified as due to the collision with the ship, as suggested by the presence of a large haematoma, and the absence of evidence of renal failure. The young age of this whale and the absence of severe chronic reaction may suggest that the infestation was not yet at an advanced chronic stage.

The Nigerian national control programme (NCP) for schistosomiasis does not have a specific action plan for female genital schistosomiasis (FGS), mainly due to gaps in epidemiological and clinical surveillance. To address this, we conducted a pilot investigation for FGS in girls (>5 and ≤15 years) and adult women (≥16 years) in four rural communities near Abeokuta, Ogun State. Urine samples were collected from 317 participants [children (n = 187), adults (n = 130)] and examined for ova of Schistosoma haematobium by microscopy. A total of 149 participants (47·0%) had egg-patent urogenital schistosomiasis [children (64·7%), adults (21·6%)], reported blood in urine was common (44·5%) as well as sign-post symptoms of FGS. To verify FGS directly, 20 adult women each underwent a gynaecological investigation by colposcopy with observed lesions classified according to the WHO FGS pocket atlas. Fourteen (70·0%) women presented with FGS as grainy-sandy patches (n = 10), homogenous yellow sandy patches (n = 6), nabothian cysts and rubbery papules (n = 1). Our study confirms FGS in Ogun State and calls for further appraisals of this disease in other areas where urogenital schistosomiasis is endemic. The Nigerian NCP should be encouraged to develop an appropriate response to FGS not only to detect it, but also to prevent it.

Large-bodied ectoparasites are often observed only in low numbers in the field. How such rarely found parasites persist and maintain viable populations has been an intriguing question inadequately addressed. The simplest hypothesis is the existence of distribution hot spots, and another, but not mutually exclusive, possibility is a form of metapopulation structure where local populations are effectively connected via dispersal. In this study, we conducted an intensive epidemiological survey of a piscicolid leech Taimenobdella amurensis to elucidate spatial population structure and potential dispersal of this rarely found parasite. Four years of potential-host screening (n = 20 664) from 28 tributaries and 10 main stem reaches in a mountain river system of Hokkaido, northern Japan, revealed that occurrences of T. amurensis (n = 1348) were confined to spring-fed tributaries. Since most spring-fed tributaries were small (<1 km in length), it would seem to be unlikely for the ectoparasite to form a persistent local population in each tributary. The main host fish was Dolly Varden charr, which is known to disperse among neighbouring tributaries. These findings suggest that, along with the host, the ectoparasite displays a potential metapopulation structure, in which host-dependent dispersion may overcome local extinction by keeping the local populations connected.

This study aimed to assess the prevalence and spatial distribution of bovine cysticercosis in the state of Goiás, Brazil; to verify its association with epidemiological variables, and to establish the economical losses for beef farms. A set of 23 255 979 bovines from 246 municipalities were slaughtered from 2007 through 2014. The prevalence of bovine cysticercosis was 0·53% [95% confidence interval (95% CI) 0·5295–0·5354]. The Central mesoregion showed a higher risk [odds ratio (OR) = 4·44; 95% CI 4·2936–4·5895] for detecting infected animals with cysticerci compared with those raised at North and Northeast mesoregion (OR = 1·02 and OR = 1·02). The microregion of Goiânia had a higher risk for bovine cysticercosis occurrence (OR = 11·05, 95% CI 10·6933–11·4099) compared with the microregion of São Miguel do Araguaia (OR = 1). None of the epidemiological variables evaluated in this study was significantly associated (P > 0·05) with bovine cysticercosis prevalence.

In conclusion, the prevalence of bovine cysticercosis in the state of Goiás, Brazil, was 0·53% and some mesoregions and microregions presented a higher risk for its occurrence. The economical losses due to its occurrence during the period ranged from US$9 260 728·57 to 11 313 816·67. These results highlighted the needs of adopting prophylactic measures and the development of political strategies in specific regions in order to control this zoonose and reduce the economical losses for beef production chain and the costs for public health.

The microaerophilic protozoan parasite Giardia lamblia occurs globally and causes dysentery in humans and animals. Since it is very sensitive to oxygen and reactive oxygen species, G. lamblia disposes over several enzymatic pathways to counter oxidative stress. One of the enzymes involved is thioredoxin reductase (TrxR), a central redox regulator that indirectly reduces peroxiredoxins via thioredoxin, an electron shuttle protein. Interestingly, the components of the TrxR-mediated redox system, including functional thioredoxins, have so far not been described despite their surmised importance for parasite survival. We aimed at filling this gap and attempted to identify functional thioredoxins and other interaction partners of TrxR in G. lamblia. To this end, we conducted database searches and expressed three recombinant candidate thioredoxins in Escherichia coli for ensuing enzyme assays. Further, co-immunoprecipitation experiments were conducted in order to identify further components of the thioredoxin redox network. Finally, the cellular localization of TrxR and peroxiredoxin 1 was determined by immunofluorescence microscopy. Surprisingly, our endeavours did not result in the identification of a functional thioredoxin or other credible interaction partners of TrxR. We, therefore, conclude that there is currently no evidence for a canonical thioredoxin redox network in G. lamblia.

Serine protease inhibitors (serpins) play essential physiological roles in a wide range of biological processes. Serpins are researched limited in Taenia solium, although some are considered to participate in host immune responses. Tsserpins were identified as typical serpins due to the primary structure of characteristic features: the serpin motif, serpin signature and reaction centre loop (RCL). RCLs of four serpin genes (TsB6, Ts4848, Ts12383 and Ts570) contained the conserved sequences of inhibitory serpins, which may involve in immune regulation. TsEP45 differed greatly from the patterns of representative serpins, suggesting that TsEP45 may be non-inhibitory. The bioinformatic analyses were supposed that Tsserpins might be a potential antigen for diagnosis. The five recombinant Tsserpin proteins were expressed and identified reacting with Cysticercus cellulosae-positive serum samples. The indirect enzyme-linked immunosorbent assay (iELISAs) based on Tsserpins were developed and validated, one of the five Tsserpins, TsEP45, showed excellent diagnostic results with 93·33% sensitivity and 94·12% specificity, respectively. This performance was in perfect accordance with the results of the bioinformatic analysis. This study provided a comprehensive demonstration of sequences and structural-based analysis of Tsserpins. The iELISAs based on five Tsserpins were developed and compared. TsEP45 was the potential species-specific antigen for developing iELISA to detect porcine cysticercosis.

The main goal of this work consisted in cloning, purifying and characterizing a protein phosphatase 2C (PP2C) from promastigotes of Leishmania major. The gene was cloned and amplified by PCR using specific oligonucleotides and the recombinant protein was purified by affinity chromatography. The peak with maximal protein concentration was analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and revealed a protein of 44·9 kDa with PP2C activity. This activity was dependent on divalent cations (Mg+2 and Mn+2) and was optimal at pH of 8·5, using phosphothreonine as the substrate. Sanguinarine inhibited the activity of the recombinant LmPP2C, while protein tyrosine phosphatase inhibitors had no effect. The recombinant LmPP2C was used to generate polyclonal antibodies. These antibodies recognized a protein of 44·9 kDa in different Leishmania species; the LmPP2C was localized in the flagellar pocket and the flagellum of promastigotes.

This cross-sectional study was undertaken to assess the status of school-based water, sanitation and hygiene (WASH) resources and soil-transmitted helminthiasis (STH) in Odeda, Ogun State, Nigeria. The status and condition of WASH resources were determined in eight selected schools (three with WASH support and five without). Stool samples were also collected from 428 pupils from both school categories and screened for STH infections. Findings showed that water and sanitation conditions of WASH resource programming schools were better than those in schools without WASH support. However, pupils’ knowledge about STH infections and basic hygiene were not significantly different between both categories of school (P > 0·05). The prevalence of Hookworm, Ascariasis and Trichuriasis cases recorded were 26·2, 18·2 and 1·6% respectively, with an overall prevalence of 33·4%. By school categories, Ascariasis (14·9 vs 20·6), Hookworm (17·7 vs 32·0), Trichuriasis (1·7 vs 1·6) and, any STH prevalence (27·4 vs 37·5) were recorded for schools with WASH resource programming and those without respectively. A greater portion of the infected children 95 (66·4%) were from schools without WASH support. Our findings imply that WASH resource may have very positive impact on the control of STH among school children. However, there is need for improvement on coverage, adequacy and maintenance of WASH facilities in school.

The protozoan parasite Trypanosoma evansi is responsible for causing Surra in a variety of mammalian hosts over a wide geographical area. In the absence of an effective vaccine and increasing resistance to current chemotherapeutic agents, peptidases from the S9 prolyl oligopeptidase family have been identified as potential drug and vaccine targets. In order to understand the function of these peptidases during infection, three null mutant clones for prolyl oligopeptidase (Δpop), prolyl oligopeptidase-like (Δpop-like) and oligopeptidase B (Δopb) were generated in T. evansi RoTat 1.2 parasites and used for infection of mice. Mice inoculated with T. evansi Δpop-like mutants were able to survive longer than other groups of mice inoculated with Δpop, Δopb mutants or wild-type parasites. The regression analysis of plasma from mice-infected over time using Δpop-like mutants showed stable levels of interleukin-10 (IL-10) (non-significant slope, P = 0·171) and declining IL-1b levels (negative slope, P = 0·04) when compared with the wild-type control that demonstrated increasing levels of IL-10 and IL-1b (P < 0·01 for both). Further analysis using mouse spleen cells in an in vitro 24 h incubation assay revealed that the percentage of IL-10 producing CD3 positive cells display significantly lower values when incubated with Δpop-like parasites than the wild-type clone (P = 0·002). These results suggest that prolyl oligopeptidase-like peptidase may play a role in immune responses during T. evansi infections by affecting interleukin concentrations in the host.

Sixteen intestinal helminth species were recovered from 271 necropsied stray dogs during a survey undertaken in Raoued and Soukra, two northeastern rural regions of Tunisia. Recorded parasites included trematodes (Brachylaemus sp., Phagicola italica, Heterophyes heterophyes), cestodes (Echinococcus granulosus, Dipylidium caninum, Diplopylidium noelleri, Mesocestoides lineatus, Mesocestoides litteratus, Taenia hydatigena, Taenia pisiformis, Taenia multiceps), nematodes (Toxocara canis, Ancylostoma caninum, Uncinaria stenocephala, Trichuris vulpis) and one acanthocephalan Macracanthorhynchus hirudinaceus. This is the first record of Brachylaemus sp., P. italica, H. heterophyes, D. noelleri and M. hirudinaceus in dogs from Tunisia. Echinococcus granulosus was found in 5·16% of dogs with a higher intensity of infection recorded in younger animals (303 worms/infected dog). Molecular analysis confirmed E. granulosus sensu stricto as the cause of canine echinococcosis. This epidemiological study investigating the status of intestinal helminths of dogs recorded a prevalence of 98·89% and a mean intensity of 87·62 worms per infected dog and confirmed the infection of 95·14% of dogs with helminths of potential zoonotic concern. Results of this study emphasize the need to interrupt parasite transmission using preventive approaches in zoonoses control programmes mainly against cystic echinococcosis, as well as reducing transmission to other animals by regular dog dosing treatments and proper management of dog populations.