In a recent study by our group on the prevalence of intestinal parasitic infections and on the knowledge, attitudes and practices of local residents of Campos dos Goytacazes, Rio de Janeiro, Brazil, we observed that about 50% of the inhabitants were parasitized and had some knowledge of intestinal parasitic infections but did not apply this knowledge in daily practice. We were thus motivated to implement strategies in health education to promote preventive measures in the locality. The goal of the present work was to evaluate the influence of health education on the prevalence of intestinal parasitic infections in the region in an effort to strengthen public policies for controlling these diseases in Brazil. The methodology adopted was based on action-research and a theoretical framework of health promotion. Our results demonstrate that the study population exhibited an enhanced awareness of the importance of disease from intestinal parasitic infections. Attitudes and practices related to prevention were significantly improved after the shared health education. In conclusion, this study allowed the shared construction of knowledge that reflected the true needs of the residents.

Biochemical studies of benzimidazole derivatives are important to determine their mode of action and activity against parasites. The lack of antihelminthic alternatives to treat parasitic infections and albendazole resistance cases make the search for new antiparasitary drugs of utmost importance. The 6-chloro-5-(1-naphthyloxy)-2-(trifluoromethyl)-1H-benzimidazole (RCB20) is a benzimidazole derivative with promising effect. This study evaluated the effect of different concentrations of RCB20 in the alternative energetic pathway of in vitro Taenia crassiceps cysticerci. The parasites were in vitro exposed to 6·5 and 13 µ m of RCB20 and albendazole sulfoxide (ABZSO). The quantification of acetate, acetoacetate, β-hydroxybutyrate, fumarate and propionate was performed by high-performance liquid chromatography. The quantification of urea, creatinine and total proteins was performed by spectrophotometry. The increase in β-hydroxybutyrate reflects the enhancement of the fatty acid oxidation in the treated groups. Volatile fatty acids secretion, acetate and propionate, was increased in the treated groups. The secretion mechanisms of the treated parasites were impaired due to organic acids increased concentrations in the cysticerci. It is possible to conclude that the metabolic effect on alternative energetic pathways is slightly increased in the parasites treated with RCB20 than the ones treated with ABZSO.

Despite the common association of human lice with abandoned or neglected people, no procedure to assess pediculosis, aimed to detect signs of neglect, exists. Investigating the two most common forms of head louse infestation, regular and severe, we define lice-markers of neglect and develop a protocol and survey form to record and assess pediculosis. The study of head lice from a deceased victim of neglect helped unravel time-length since death, frequency of exposure to neglect and the cause and circumstances related to the death. Nit-clusters are markers of neglect, indicating length and frequency of neglect episodes. In the case study used here that culminated in the death of the victim, sustained abandonment started circa 2 years before discovery. The lice suggested that death was caused by overconsumption of a powerful calcium channel blocker, an antihypertensive, an excess of which in lice food supply (blood) stops oogenesis. Despite hosting thousands of adult females on the hair, lice reproduction stopped and nits were no longer developed or deposited on the hairs at the root end. This short distance of the shaft with no nits provided a time estimation of overdosing of almost 2 months before death.

Parasite–host interactions mediated by cell surface proteins have been implicated as a critical step in infections caused by the microsporidian Nosema bombycis. Such cell surface proteins are considered as promising diagnostic markers and targets for drug development. However, little research has specifically addressed surface proteome identification in microsporidia due to technical barriers. Here, a combined strategy was developed to separate and identify the surface proteins of N. bombycis. Briefly, following (1) biotinylation of the spore surface, (2) extraction of total proteins with an optimized method and (3) streptavidin affinity purification of biotinylated proteins, 22 proteins were identified based on LC-MS/MS analysis. Among them, 5 proteins were confirmed to be localized on the surface of N. bombycis. A total of 8 proteins were identified as hypothetical extracellular proteins, whereas 7 other hypothetical proteins had no available function annotation. Furthermore, a protein with a molecular weight of 18·5 kDa was localized on the spore surface by western blotting and immunofluorescence analysis, even though it was predicted to be a nuclear protein by bioinformatics. Collectively, our work provides an effective strategy for isolating microsporidian surface protein components for both drug target identification and further diagnostic research on microsporidian disease control.

Light gradients are an inherent feature in aquatic ecosystems and play a key role in shaping the biology of phytoplankton. Parasitism by chytrid fungi is gaining increasing attention as a major control agent of phytoplankton due to its previously overlooked ubiquity, and profound ecological and evolutionary consequences. Despite this interest, if and how light conditions modulate phytoplankton chytridiomycosis remains poorly studied. We investigated life-history traits of a chytrid parasite, Rhizophydium megarrhizum, under different light intensities and spectral compositions when infecting two closely related planktonic cyanobacteria with different light-harvesting strategies: Planktothrix rubescens and P. agardhii. In general, parasite transmission was highest under light conditions (both intensity and quality) that maximized growth rates for uninfected cyanobacteria. Chytrid encystment on hosts was significantly affected by light intensity and host strain identity. This likely resulted from higher irradiances stimulating the increased discharge of photosynthetic by-products, which drive parasite chemotaxis, and from strain-specific differences at the cell-surface. Comparisons of parasite transmission and host growth rates under different light conditions suggest the potential for epidemic development at higher irradiances, whereas host and parasite could coexist without epidemic outbreaks at lower light levels. These results illustrate the close relationship between parasite transmission and host fitness, which is ultimately modulated by the external environment.

Investigations were conducted on the infection rates and transmission charecteristics of sterile male Glossina morsitans morsitans for Trypanosoma vivax, T. congolense and T. brucei. Pupae were irradiated after the first flush of female emergences with 7, 10 or 13 krad. in a 137caesium radiation source under ambient conditions. The emergent males were fed on a T. viuax-infected goat at peak parasitaemia. They were subsequently mated at 8 days old with 3-day-old normal, virgin females. A batch of sexually fertile males which had been infected as tenerals on the goat at the same time were similarly mated to serve as controls. All the tsetse were maintained on rabbits' ears; the survival and reproductive performance were monitored for seven age-group periods of 9 days each. The sterility rates of the males were 73, 91 and 98% for the 7, 10 and 13 krad. doses of radiation; the percentage of T. vivax infection rates were 78·3, 82·3 and 74·4, respectively. For the control males, the fecundity of the mated females was 90% and the infection rate was 75·7%. In all other experiments, the 10 krad. dose was selected since both the survival and the sterility of the irradiated males were good. The T. vivax-challenged cows and goats died with symptoms of anaemia. There was no difference in the transmission characteristics between sterile and fertile vectors. There was also no significant difference between the sterile and normal males in the infection rates and the transmission frequency of T. congolense and T. brucei to cattle, goats and mice. These results indicate that release of sterile male tsetse in tsetse control programmes will potentially increase the trypanosomiasis risk in the affected area. Consideration must therefore be given to integrating adequate surveillance and chemotherapeutic measures for protection of man and his domestic livestock in the region during the period of such tsetse control campaigns.

The effects of malaria infection on RBC sialic acids and sialoglycoproteins were studied with asexual blood-stage infections of Plasmodium knowlesi in rhesus monkeys. Glycoprotein radio-isotope labelling methods were used to compare the sialoglycoproteins of normal RBC and P. knowlesi schizont-infected RBC (SI-RBC). Tritiation of glycoproteins from SI-RBC with the standard sialidase + galactose oxidase/NaB3H4 method or standard periodate/NaB3H4 method was significantly decreased when compared to normal RBC. However, tritium uptake into glycoproteins was normal when SI-RBC were treated with 5-fold higher concentrations of both enzymes in the first labelling method, or with a 5-fold increase in the molar ratio of periodate to sialic acid in the second method. The mobility of tritiated host cell glycoproteins on SDS–polyacrylamide gels was identical for SI-RBC and normal RBC. New bands, possibly glycoproteins, of 230, 160, 90, 52, and 30 kDa were detected after labelling SI-RBC by the modified periodate/NaB3H4 method. Sialic acid analysis of normal rhesus monkey RBC (62μg/1010 RBC) revealed that 46% of the total sialic acid was N-glycolylneuraminic acid, 33% was N-acetyl-9-O-acetylneuraminic acid, and the remainder N-acetylneuraminic acid. SI-RBC collected either directly from infected monkeys or after in vitro culture of ring-infected RBC in horse serum, had increased total sialic acid (126 or 115μg/1010 RBC, respectively). The sialic acid content of infected RBC must increase during parasite development since RBC infected with ring-stage P. knowlesi had the same content as normal RBC. There was no significant difference in the ratio of the three sialic acids of SI-RBC and normal RBC. In contrast, the uninfected RBC from infected blood of different monkeys showed marked variation in sialic acid composition and generally had a lower sialic acid content than normal RBC.

Toxoplasma gondii is an obligate intracellular parasite of phylum Apicomplexa. To facilitate high-efficiency invasion of host cells, T. gondii secretes various proteins related to the moving junction (MJ) complex from rhoptries and micronemes into the interface between the parasite and host. AMA1/RON2/4/5/8 is an important MJ complex, but its mechanism of assembly remains unclear. In this study, we used the CRISPR-Cas9 system to generate a derivative of T. gondii strain RH with a null mutation in TgRON4, thought to be an essential MJ component. Deficiency of TgRON4 moderately decreased invasion ability relative to that of the wild-type parasite. In addition, expression of the endogenous N-terminal fragment of RON5 decreased in the mutant. Together, the results improve our understanding of the assembly mechanism of the MJ complex of T. gondii and raise the possibility of developing new therapeutic drugs that target this complex.

The genus Entamoeba comprises mostly gut parasites and commensals of invertebrate and vertebrate animals including humans. Herein, we report a new species of Entamoeba isolated from the gut of Asian swamp eels (Monopterus albus) in northern Thailand. Morphologically, the trophozoite is elongated and has a single prominent pseudopodium with no clear uroid. The trophozoite is actively motile, 30–50 µm in length and 9–13 µm in width. Observed cysts were uninucleate, ranging in size from 10 to 17.5 µm in diameter. Chromatin forms a fine, even lining along the inner nuclear membrane. Fine radial spokes join the karyosome to peripheral chromatin. Size, host and nucleus morphology set our organism apart from other members of the genus reported from fish. The SSU rRNA gene sequences of the new isolates are the first molecular data of an Entamoeba species from fish. Phylogenetic analysis places the new organism as sister to Entamoeba invadens. Based on the distinct morphology and SSU rRNA gene sequence we describe it as a new species, Entamoeba chiangraiensis.

Protection against infection with Trichinella spiralis is conferred upon mice by the passive transfer to them of a specific immune serum from rabbits. A smaller percentage of mice treated with the immune serum die, and fewer larvae invade the muscles of the treated mice than among control animals. The action of the antibody of the immune serum appears to be directed specifically against the ingested larvae which are maturing to adult worms in the intestine of the infected animals. The results obtained thus far indicate that an immune serum would have little therapeutic value in the later stages of the disease.

Since I published (1925) a description of this interesting new species of a Caryophyllaeid, Woodland (1926) has suggested that the bodies which I described as post-ovarian vitellaria (1925, p. 233, fig. 2, p.ov.vit.) are in reality ovarian follicles, and that, therefore, the worm is a Lytocestus and not Caryophyllaeus. Southwell in his papers (1928 and 1930) has embodied my original description of this worm and has concluded the description by referring to Woodland's remark regarding the post-ovarian vitellaria, without definitely assigning the species to the genus Lytocestus. With additional material at my disposal, it was possible to re-examine its anatomy, and I have found that the bodies described and figured by me as post-ovarian vitellaria are in reality ovarian follicles. I also take this opportunity of publishing a more complete and, I hope, a more accurate description of its general anatomy.

By many observers Negri bodies have been considered to be parasitic in nature (Negri, 1903; Babes, 1907). Williams and Lowden (1906) go further and describe the life cycle of these bodies, regarding them as belonging to the Sporozoa, and give to them the name of Neuroryctes hydrophobiae. Calkins (1910), although he states that the parasitic nature of these bodies is not proven, still evidently inclines to that view. In his criticism of the work of Williams and Lowden he comes to differ from them as regards the classification of the supposed organisms. He thinks that their variable forms, the uninucleate condition, the occurrence of a state of distributed chromatin, and the budding phenomenon, are characteristic not of Sporozoa but of parasitic Rhizopods. His opinion is that the distributed chromatin masses in the Negri bodies are in all probability representative of the idiochromidia which are so characteristic of Rhizopods.

The stink organs are different in structure and position in the adult and the larval stages.

The stink organs of the adult are composed of (a) a pair of glands, (b) a central reservoir with two backwardly-directed lateral reservoirs, (c) a median kidney-shaped organ in the central reservoir, and (d) a pair of lateral external openings.

Each gland is a multicellular compound structure, opening into the central reservoir. It is described for the first time in this paper.

The whole of the stink organ of the adult is formed in the last larval stage from a pair of invaginations of the epithelial lining of the body-wall.

In the larval stages the stink organs are simple glands, situated dorsally in abdominal segments III to V.

The function of the stink organs is defensive and in the adult perhaps also sexual.

The Dipterous Family, Tachinidae, comprises a very large number of species whose larvae live as parasites within other insects, particularly in their larval forms.

The purpose of this note is to record the occurrence of a haemogregarine parasite in the red blood corpuscles of the South American lung-fish, Lepidosiren paradoxa.

The increase of contact between natural and rural areas is prominent in Brazil, due to agricultural activities and concern with the environmental conservation. In this context, domestic animals, wild fauna and humans are exposed to mutual exchange of parasites, microorganisms and diseases. We studied tick parasitism of wild carnivores and domestic dogs, and the environmental of questing ticks, in extensive cattle ranch areas intermingled with natural vegetation, and in a natural reserve, both in a region of Cerrado biome, Midwestern Brazil. From 2008 to 2015, we inspected 119 wild carnivores from nine species, and collected six tick species (Amblyomma sculptum, Amblyomma ovale, Amblyomma dubitatum, Amblyomma tigrinum, Dermacentor nitens and Rhipicephalus microplus). The most numerous and infested hosts were Cerdocyon thous, Lycalopex vetulus, Chrysocyon brachyurus, Puma concolor and Conepatus amazonicus. From 139 domestic dogs, we collected A. sculptum, Rhipicephalus sanguineus and R. microplus. From vegetation, samplings resulted in A. sculptum, A. dubitatum, A. ovale, Amblyomma rotundatum and R. microplus, with dominance of A. sculptum. Domestics and wild animals presented high overlapping of infestations by A. sculptum, a generalist and anthropophilic tick species. This tick is the most important vector of the Brazilian spotted fever, a lethal human disease. This fact elicits attention and requires efforts to monitor the presence of pathogens vectored by ticks circulating in this type of agroecosystem, including in other regions of the Brazil, because the most of the natural vegetation remaining have been increasingly immersed in pastures and agricultural matrix.

In a recent paper (Journal of Parasitology, 1910, III. pp. 245—54) I described a new trichomonad (Trichomastixc trichopterorum) and a spirochaete from the hind-gut of certain trichopterous larvae. I also mentioned the occurrence along with these parasites of another peculiar flagellate, which, at the time, I was disposed to consider as closely related to Macrostoma caulleryi, Alexeieff.

The role of pulmonary cellular responses in the induction and expression of immunity to Schistosoma mansoni has been evaluated. From experiments in which mice were challenged at intervals after vaccination, we conclude that the resistance mechanism operating in the lungs develops between days 11 and 20. Injection of 51Cr-labelled splenocytes revealed that mononuclear cell recruitment to the lungs, stimulated by the arrival of attenuated schistosomula, intensified progressively between days 10 and 16 post-vaccination. The increased cellularity was reflected in a 19·5% augmentation in the wet-weight index (WW). The period of enhanced cell recruitment therefore coincided with the build-up of resistance. By day 22 post-vaccination infiltration had declined, whilst WW remained elevated. This indicates the persistence of recruited cells, which include schistosome-reactive T lymphocytes, in the lungs. We were unable to demonstrate augmented recruitment of 51Cr-labelled cells after challenge of vaccinated mice, but WW rose slightly, peaking on day 12. Although clearly of a lower order than the primary response, the secondary response was more rapid, implying the existence of immunological memory. These results accord with the concept that schistosome-reactive T lymphocytes recruited after vaccination ‘arm’ the lungs against the arrival of challenge parasites.

Naive CBA/Ca mice and CBA/Ca mice vaccinated 4 weeks previously with radiation-attenuated cercariae of Schistosoma mansoni were subjected to 550 rad of whole body (gamma) irradiation and then challenged 3 days laterwith normal cercariae. The perfusion recovery data showed that this procedure reduced theprimary worm burden in naive mice by 22% and the challenge worm burden in vaccinated mice by 82%. Irradiation also ablated the peripheral blood leucocytes of both mouse groups by 90%–100% at the time of challenge. Histological data revealed that such treatment caused a dramatic change in number, size and leucocyte composition of cutaneous inflammatory skin reactions that characterize challenged vaccinated mice and are known to entrap invading larvae; cutaneous eosinophils were preferentially abolished by this treatment. Polyvaccine mouse serum that conferred protection passively upon naive recipient mice, failed to protect naive/irradiated mice when administered by the same protocol. Distraction of macrophages by treatment of mice with silica did not affect the establishment of a primary worm burden and reduced the protection exhibited by vaccinated mice by only 16%. These data indicate that radio-sensitive cells are important to both innate and specific acquired resistance in this mouse model and that macrophages contribute only marginally to the expression of vaccine immunity.