[STRUCTURAL, MOLECULAR AND FUNCTIONAL FEATURES OF NEMATODE SURFACES AND THE POSSIBILITY OF ANTHELMINTIC DRUGS DEVELOPMENT (REVIEW)].

Helminthiases caused by parasitic nematodes are widespread in different regions of the world. The main adaptation for overcoming adverse conditions is a barrier properties of the cuticle surface structure, which differs from the membrane teguments of trematodes and cestodes. Different types of nematodes have specific structural and biochemical adaptations at different stages of their life cycle. While creating specific areas of habitat and nutrition, some types of parasites change the morphology and functioning of the host tissues. Ascaris suum and Caenorabditis elegans were widely used as model organisms in the study of genetics, biochemistry of nematodes. Studying of biochemistry and molecular biology of structural components of nematode surfaces is important for development of effective and safe anthelmintic drugs. The differences in the structure and functioning of transport enzymes of parasites and humans will help to create effective specific inhibitors and anthelmintic remedies. An important point of application of anthelmintic drugs can serve as inorganic ions transport proteins in the membranes of the surfaces. Glycolipids of cuticle contribute to the evasion from the host immune system, protecting the surface proteins from degradation by proteases. Study of helminth surfaces makes an important contribution to the development of anthelmintic drugs and vaccines, for helminthiasis treat.

Ascaris and hookworm transmission in preschool children in rural Panama: role of subsistence agricultural activities.

This longitudinal study explored whether aspects of subsistence agriculture were associated with presence and intensity of Ascaris and hookworm in preschool children in rural Panama. Questionnaires were used to collect data on household socio-demographics, child exposure to agriculture and household agricultural practices. Stool samples were collected from children (6 months-5 years) at 3 time points, with albendazole administered after each to clear infections, resulting in 1 baseline and 2 reinfection measures. A novel Agricultural Activity Index (AAI) was developed using principal components analysis to measure the intensity of household agricultural practices. Zero-inflated negative binomial regression models revealed baseline hookworm egg counts were higher if children went to the agricultural plot and if the plot was smaller. Baseline and reinfection Ascaris egg counts were higher if children went to the plot and households had higher AAI, and higher at baseline if the plot was smaller. Caregiver time in the plot was negatively associated with baseline Ascaris egg counts, but positively associated with baseline hookworm and Ascaris reinfection egg counts. Children who spent more time playing around the home were less likely to be infected with Ascaris at baseline. We conclude that preschool child exposure to subsistence agriculture increased Ascaris and hookworm intensity.

Seroepidemiology of human Toxocara and Ascaris infections in the Netherlands.

Toxocara canis, Toxocara cati and Ascaris suum are worldwide-distributed zoonotic roundworms of dogs, cats and pigs, respectively. The epidemiology of these parasites in developed countries is largely unclear. Two countrywide cross-sectional serosurveys were therefore conducted in the Netherlands in 1995/1996 and 2006/2007 to investigate the prevalence, trends and risk factors for human Toxocara and Ascaris infections in the general population. The Netherlands is characterized by high pig production, freedom from stray dogs and virtual absence of autochthonous infections with the human-adapted roundworm Ascaris lumbricoides. Over the 10 years between the two serosurveys, Toxocara seroprevalence decreased significantly from 10.7 % (n = 1159) to 8.0 % (n = 3683), whereas Ascaris seroprevalence increased significantly from 30.4 % (n = 1159) to 41.6 % (n = 3675), possibly reflecting concomitant improvements in pet hygiene management and increased exposure to pig manure-contaminated soil. Increased anti-Toxocara IgGs were associated with increasing age, male gender, contact with soil, ownership of cats, cattle or pigs, hay fever, low education, high income and non-Western ethnic origin. Increased anti-Ascaris IgGs were associated with increasing age, owning pigs, low education, childhood geophagia and non-Dutch ethnic origin. Besides identifying specific groups at highest risk of Toxocara and Ascaris infections, our results suggest that these infections mainly occur through environmental, rather than foodborne, routes, with direct contact with soil or cat and pig ownership being potentially modifiable exposures.

[ERRORS IN DIAGNOSIS AND TREATMENT OF IMMUNODEPENDENT PATHOLOGY (ORIGINAL CONCEPT)].

Based on many years of experience in 2009, we developed the original concept of a mixed approach to the treatment of infectious diseases in patients. During 2.5 years(from 2013 to June 2015) to have applied for consultative-diagnostic help of 3965 patients who had not verified the primary diagnosis. The basic principle of verification of the pathology of the removal of various causes immunosuppression. Based on our extensive, research and observation was often found in patients ascaridosis (55%) and giardiasis (65%), as a possible cause of immunosuppression. In 13% of patients was found the mucosal candidiasis. Among frequently and chronically ill persons we identified the active forms of Epstein-Barr virus (quantitative polymerase chain reaction in saliva) in 40%. The criterion for assessing performance immunogram was a decrease of two sigmal deviation from the lower age limit. In the study of neutrophil myeloperoxidase content observed decline (< 60%) in 99 (9.7%) of 1015 patients, indicating a fairly common cause of long-term permit infection in the tissues and persistence C. albicans. In the study of lymphocyte subpopulations often demonstrated reduction in the number of natural killer cells (26.7% of subjects), which shows a decline of one of the most important factors of congenital immunity. Among the humoral immune disorders often noted the decrease of total IgG (2.4%) and its subclass IgG1 (22.1%), indicating a significant diagnostic value determination of IgG subclasses it even with normal serum total. Thus, approximately 76% of patients often suffer set of a decrease immunity. Patients developed with mixed infections caused by various bacterial, fungal, viral and protozoan agents and worms. Immunological study of patients should be redynamics after eliminating the causes immunosuppression and sanitation foci of infection. Only multi-level examination of the patient will determine the final diagnosis and adequate treatment.

Role of posttranslational modifications in C. elegans and ascaris spermatogenesis and sperm function.

Generally, spermatogenesis and sperm function involve widespread posttranslational modification of regulatory proteins in many different species. Nematode spermatogenesis has been studied in detail, mostly by genetic/molecular genetic techniques in the free-living Caenorhabditis elegans and by biochemistry/cell biology in the pig parasite Ascaris suum. Like other nematodes, both of these species produce sperm that use a form of amoeboid motility termed crawling, and many aspects of spermatogenesis are likely to be similar in both species. Consequently, work in these two nematode species has been largely complementary. Work in C. elegans has identified a number of spermatogenesis-defective genes and, so far, 12 encode enzymes that are implicated as catalysts of posttranslational protein modification. Crawling motility involves extension of a single pseudopod and this process is powered by a unique cytoskeleton composed of Major Sperm Protein (MSP) and accessory proteins, instead of the more widely observed actin. In Ascaris, pseudopod extension and crawling motility can be reconstituted in vitro, and biochemical studies have begun to reveal how posttranslational protein modifications, including phosphorylation, dephosphorylation and proteolysis, participate in these processes.

An environmental evaluation of urine-diverting dry toilets in Hiloweyn Camp, Dollo Ado, Ethiopia.

Safe and hygienic management of human waste is essential in humanitarian settings. Urine-diverting dry toilets (UDDTs) can enable this management in some humanitarian emergency settings. A seeded, longitudinal environmental study was conducted in Hiloweyn refugee camp, Dollo Ado, Ethiopia, to measure Escherichia coli and Ascaris suum ova inactivation within closed UDDT vaults and to document environmental conditions (temperature, moisture content, and pH) that could influence inactivation. Hiloweyn camp represented an optimal location for a desiccation-based sanitation technology such as the UDDT. E. coli and Ascaris ova inactivation was observed in UDDTs under warm, dry, alkaline conditions at 6, 9, and 12 months of storage; UDDTs with samples containing <1000 E. coli/g total solids increased from 30 % to 95 % over 12 months, and a >2.8-log10 reduction in Ascaris ova viability was observed after 6 months. Additional laboratory-based studies were conducted to provide insights into the field study findings and study the impact of hydrated lime on E. coli and Ascaris ova inactivation. Results suggest that adding hydrated lime to elevate pH > 12 may increase inactivation and decrease storage time. Overall, UDDTs could contribute to the safe and hygienic management of human waste in comparable warm and dry humanitarian settings.

[Nematodes of humans in the Primorye Territory].

Nematodes occupy the top in the general pattern of human parasitic diseases in the Primorye Territory. In the south of the Far East, there are a total of 28 nematode species that can parasitize man. However, the authors have identified only 8 nematode-induced diseases, such as ascariasis, enterobiasis, toxocariasis, trichocephaliasis, anisakiasis, trichinosis, dirofilariasis, dioctophymosis. The latter has been found only once in the 1920s. According to official statistical data, the proportion of ascariasis and enterobiasis accounted for 43.8 and 53.5% of the total number of helminthiases, respectively.

Ammonia inactivation of Ascaris ova in ecological compost by using urine and ash.

Viable ova of Ascaris lumbricoides, an indicator organism for pathogens, are frequently found in feces-derived compost produced from ecological toilets, demonstrating that threshold levels of time, temperature, pH, and moisture content for pathogen inactivation are not routinely met. Previous studies have determined that NH(3) has ovicidal properties for pathogens, including Ascaris ova. This research attempted to achieve Ascaris inactivation via NH(3) under environmental conditions commonly found in ecological toilets and using materials universally available in an ecological sanitation setting, including compost (feces and sawdust), urine, and ash. Compost mixed with stored urine and ash produced the most rapid inactivation, with significant inactivation observed after 2 weeks and with a time to 99% ovum inactivation (T(99)) of 8 weeks. Compost mixed with fresh urine and ash achieved a T(99) of 15 weeks, after a 4-week lag phase. Both matrices had relatively high total-ammonia concentrations and pH values of >9.24 (pK(a) of ammonia). In compost mixed with ash only, and in compost mixed with fresh urine only, inactivation was observed after an 11-week lag phase. These matrices contained NH(3) concentrations of 164 to 173 and 102 to 277 mg/liter, respectively, when inactivation occurred, which was below the previously hypothesized threshold for inactivation (280 mg/liter), suggesting that a lower threshold NH(3) concentration may be possible with a longer contact time. Other significant results include the hydrolysis of urea to ammonia between pH values of 10.4 and 11.6, above the literature threshold pH of 10.

Serologic evidence that ascaris and toxoplasma infections impact inflammatory responses to Helicobacter pylori in Colombians.

BACKGROUND: Helicobacter pylori-infected children from coastal Tumaco, Colombia, have more parasitism, and adults have lower gastric cancer risk compared with high-altitude Pasto/Tuquerres residents. Because helminth and Toxoplasma gondii infections alter helicobacter gastritis in rodent models, we determined whether seropositivity to Ascaris lumbricoides or T. gondii was associated with Th2-IgG1 or Th1-IgG2 responses to H. pylori. METHODS: Sera (240) from the two populations were evaluated for A. lumbricoides and T. gondii seropositivity and results correlated with IgE and IgG isotype responses to H. pylori. RESULTS: Most Tumaco children and adults were seropositive for A. lumbricoides (89%, 66%), T. gondii (59%, 98%), or both (45%, 66%). In contrast, seropositivity among Pasto/Tuquerres children was much lower (9%A. lumbricoides, 11%T. gondii, and 2% dual positive) but increased in adults (58%A. lumbricoides, 82%T. gondii, and 41% dual positive). A. lumbricoides seropositivity correlated with elevated IgE and anti-inflammatory Th2-IgG1 responses to H. pylori, while T. gondiigondii seropositivity was linked to elevated IgE, pro-inflammatory Th1-IgG2, IgG3, and IgG4 responses to H. pylori. Individuals with high T. gondii titers had reduced Th1-IgG2, IgG3, and IgG4 responses to H. pylori. CONCLUSIONS: Results support regional differences for childhood parasitism and indicate A. lumbricoides and T. gondii infections may impact inflammatory responses to H. pylori and partially explain differences in gastric cancer risk in Colombia.

Ascaris: development of selected genotypes in mice.

Using nucleotide variation in the first internal transcribed spacer of nuclear ribosomal DNA, five different genotypes (designated G1-G5) have been identified and the preponderance of genotype G1 in humans and of genotype G3 in pigs led to the proposal that parasites bearing the two genotypes have an affinity for a particular host species. A subsequent study using eggs of genotype G1 from humans and G3 from pigs to infect pigs and mice indicated that there is a significant difference in the ability to infect and establish as larvae in mice and as adults in pigs between the two genotypes. Extending previous investigations, the present study investigated whether there are differences in development as designated by egg hatching, larvae migration and distribution in the mice between the Ascaris strains with known genotypes. Ascaris eggs of genotypes G1 (predominating in human-derived worms) and G3 (predominating in pig-derived worms) were used to infect C57BL/6 mice orally. Eggs/larvae were examined from the small and large intestines, thoracic and abdominal cavities, peripheral blood, livers and lungs at intervals of 2h until 12h post-infection, then periodically until 34 days of infection. Results showed distinct differences in egg hatching (the timing and location of hatching, and the numbers hatched), and in larvae migration and distribution (the means and constituent ratios, the time of peak recovery, and larvae reappearing in intestines) between the two strains. The results can explain the findings of significantly higher larval recovery of genotype G1 than G3 in the mice, and may shed some enlightenment to understand the difference in host affiliation of Ascaris of different genotypes.

Mammalian metallopeptidase inhibition at the defense barrier of Ascaris parasite.

Roundworms of the genus Ascaris are common parasites of the human gastrointestinal tract. A battery of selective inhibitors protects them from host enzymes and the immune system. Here, a metallocarboxypeptidase (MCP) inhibitor, ACI, was identified in protein extracts from Ascaris by intensity-fading MALDI-TOF mass spectrometry. The 67-residue amino acid sequence of ACI showed no significant homology with any known protein. Heterologous overexpression and purification of ACI rendered a functional molecule with nanomolar equilibrium dissociation constants against MCPs, which denoted a preference for digestive and mast cell A/B-type MCPs. Western blotting and immunohistochemistry located ACI in the body wall, intestine, female reproductive tract, and fertilized eggs of Ascaris, in accordance with its target specificity. The crystal structure of the complex of ACI with human carboxypeptidase A1, one of its potential targets in vivo, revealed a protein with a fold consisting of two tandem homologous domains, each containing a beta-ribbon and two disulfide bonds. These domains are connected by an alpha-helical segment and a fifth disulfide bond. Binding and inhibition are exerted by the C-terminal tail, which enters the funnel-like active-site cavity of the enzyme and approaches the catalytic zinc ion. The findings reported provide a basis for the biological function of ACI, which may be essential for parasitic survival during infection.

Genomics of the Parasitic Nematode Ascaris and Its Relatives.

Nematodes of the genus Ascaris are important parasites of humans and swine, and the phylogenetically related genera (Parascaris, Toxocara, and Baylisascaris) infect mammals of veterinary interest. Over the last decade, considerable genomic resources have been established for Ascaris, including complete germline and somatic genomes, comprehensive mRNA and small RNA transcriptomes, as well as genome-wide histone and chromatin data. These datasets provide a major resource for studies on the basic biology of these parasites and the host-parasite relationship. Ascaris and its relatives undergo programmed DNA elimination, a highly regulated process where chromosomes are fragmented and portions of the genome are lost in embryonic cells destined to adopt a somatic fate, whereas the genome remains intact in germ cells. Unlike many model organisms, Ascaris transcription drives early development beginning prior to pronuclear fusion. Studies on Ascaris demonstrated a complex small RNA network even in the absence of a piRNA pathway. Comparative genomics of these ascarids has provided perspectives on nematode sex chromosome evolution, programmed DNA elimination, and host-parasite coevolution. The genomic resources enable comparison of proteins across diverse species, revealing many new potential drug targets that could be used to control these parasitic nematodes.

Trilateral Relationship: Ascaris, Microbiota, and Host Cells.

Ascariasis is a globally spread intestinal nematode infection of humans and a considerable concern in pig husbandry. Ascaris accomplishes a complex body migration from the intestine via the liver and lung before returning to the intestine. Tissue migration and the habitat shared with a complex microbial community pose the question of how the nematode interacts with microbes and host cells from various tissues. This review addresses the current knowledge of the trilateral relationship between Ascaris, its microbial environment, and host cells, and discusses novel approaches targeting these interactions to combat this widespread infection of livestock and man.

Neuropeptide physiology in helminths.

Parasitic worms come from two distinct, distant phyla, Nematoda (roundworms) and Platyhelminthes (flatworms). The nervous systems of worms from both phyla are replete with neuropeptides and there is ample physiological evidence that these neuropeptides control vital aspects of worm biology. In each phyla, the physiological evidence for critical roles for helminth neuropeptides is derived from both parasitic and free-living members. In the nematodes, the intestinal parasite Ascaris suum and the free-living Caenorhabditis elegans have yielded most of the data; in the platyhelminths, the most physiological data has come from the blood fluke Schistosoma mansoni. FMRFamide-like peptides (FLPs) have many varied effects (excitation, relaxation, or a combination) on somatic musculature, reproductive musculature, the pharynx and motor neurons in nematodes. Insulin-like peptides (INSs) play an essential role in nematode dauer formation and other developmental processes. There is also some evidence for a role in somatic muscle control for the somewhat heterogeneous grouping ofpeptides known as neuropeptide-like proteins (NLPs). In platyhelminths, as in nematodes, FLPs have a central role in somatic muscle function. Reports of FLP physiological action in platyhelminths are limited to a potent excitation of the somatic musculature. Platyhelminths are also abundantly endowed with neuropeptide Fs (NPFs), which appear absent from nematodes. There is not yet any data linking platyhelminth NPF to any particular physiological outcome, but this neuropeptide does potently and specifically inhibit cAMP accumulation in schistosomes. In nematodes and platyhelminths, there is an abundance of physiological evidence demonstrating that neuropeptides play critical roles in the biology of both free-living and parasitic helminths. While it is certainly true that there remains a great deal to learn about the biology of neuropeptides in both phyla, physiological evidence presently available points to neuropeptidergic signaling as a very promising field from which to harvest future drug targets.

Sludge accumulation in an anaerobic pond and viability of helminth eggs: a case study in Burkina Faso.

Accumulation rates and pathogen concentrations in primary stabilization pond sludges in developing countries are important parameters for adequate sludge management and the safeguarding of public health with sludge reuse in agriculture. An anaerobic pond has been investigated for sludge accumulation rates and helminth egg viability after four years of operation in Burkina Faso. The rate of sludge accumulation was measured at 0.037 m(3)/capita-year or 2.26 kg dry weight/capita-year. An equation describing vertical distribution of total solids in the accumulated sludge was found to be adequately represented by a regression equation. Influent helminth egg concentrations were reduced on average by 90% in the anaerobic pond effluent. Ascaris lumbricoides and Ancylostoma sp. were the most common eggs present in the sludge after four years of operation. The average concentration of helminth eggs in pond sludge was 536 eggs/g TS, and the percentages of viability ranged from 10.8% (47 viable eggs/g TS) to 57.2 (1,772 viable eggs/g TS, with an average rate of 36% (336 viable eggs/g TS). From a sludge depth and section study, egg viability was found to be randomly distributed in the sludge layer.

Viability of Ascaris and other helminth genera non larval eggs in different conditions of temperature, lime (pH) and humidity.

Helminth eggs are the pathogens most resistant to inactivation during sludge and wastewater treatment. For this reason, in several regulations and the WHO guidelines for wastewater and excreta reuse for agriculture and aquaculture they are considered as indicators of the performance of the treatment process. Conditions required to inactivate helminth eggs, notably Ascaris lumbricoides, are recommended in the literature, but in practice these have not always proven effective, not only for Ascaris but also other genera of helminth eggs. The objective of this research was to study the inactivation of a high total content of non larval Ascaris and other genera of helminth eggs of medical importance to developing countries under controlled conditions of (a) temperature (30 °C to 80 °C) and humidity (80, 90 and 95%) and (b) lime doses (15 and 20% of CaO w/w dry basis) and humidity (90 and 80%), using different contact times in both cases. The inactivation data obtained for different genera of non larval helminth eggs is presented. Results showed that there is a combination of conditions (temperature, pH and humidity) that is optimal for inactivation. To completely inactivate any genera of non larval helminth eggs: (a) a temperature above 70 °C and 80% humidity for a duration of 120 min; and, (b) a 20% CaO dose (pH 12.5) and a humidity level of 80% for a duration of 8 months are needed. With regard to the resistance of different genera of helminth eggs, Ascaris, Toxocara and Taenia, in that order, were the most resistant, while the most sensitive were Trichuris and Hymenolepis. For most of the conditions tested Ascaris showed the highest resistance, probably due to the chemical arrangement of its membrane.

Ascaris.

Wang and Davis provide an overview of the parasite nematode Ascaris, including the history of its role in biological research.

Zygote formation in Ascaris lumbricoides (Nematoda).

Ultrastructural observations of the in utero sperm of Ascaris lumbricoides reveal that it consists of a relatively clear, ameboid anterior region and a conical posterior region containing numerous surface membrane specializations, dense mitochondria, a lipid-like refringent body of variable size, and a dense nucleus which lacks an apparent nuclear envelope. No acrosomal complex was observed. Pseudopods emanating from the anterior cytoplasm make first contact with the primary oocytes and appear to be responsible for the localized removal of the extraneous coat covering the oolemma. Subsequently the gamete membranes interdigitate and finally fuse. Because this pseudopodial action appears similar to that reported for the acrosomal filaments in flagellated sperm, the anterior region of the Ascaris sperm is thought to serve an acrosomal function. Following gamete-membrane fusion, the sperm nucleus acquires a particulate appearance and becomes disorganized. Once inside the oocyte, the sperm cytoplasm consists of dense mitochondria, ribosomes, and vesicles derived from the surface membrane specializations. The refringent body, whose contents possibly contribute to the synthesis of ribosomes, is usually absent by the time the sperm cytoplasm attains a central position in the egg.

Obliquely striated muscle. 3. Contraction mechanism of Ascaris body muscle.

Segments of the obliquely striated body muscle of Ascaris were fixed at minimum body length after treatment with acetylcholine and at maximum body length after treatment with piperazine citrate and then studied by light and electron microscopy. Evidence was found for two mechanisms of length change: sliding of thin filaments with respect to thick filaments such as occurs in cross-striated muscle, and shearing of thick filaments with respect to each other such that the degree of their stagger increases with extension and decreases with shortening. The shearing mechanism could account for great extensibility in this muscle and in nonstriated muscles in general and could underlie other manifestations of "plasticity" as well. In addition, it is suggested that the contractile apparatus is attached to the endomysium in such a way that the sarcomeres can act either in series, as in cross-striated muscle, or individually. Since the sarcomeres are virtually longitudinal in orientation and are almost coextensive with the muscle fiber, it would, therefore, be possible for a single sarcomere contracting independently to develop tension effectively between widely separated points on the fiber surface, thus permitting very efficient maintenance of isometric tension.

A unique cytoskeleton associated with crawling in the amoeboid sperm of the nematode, Ascaris suum.

Nematode sperm extend pseudopods and pull themselves over substrates. They lack an axoneme or the actin and myosins of other types of motile cells, but their pseudopods contain abundant major sperm protein (MSP), a family of 14-kD polypeptides found exclusively in male gametes. Using high voltage electron microscopy, a unique cytoskeleton was discovered in the pseudopod of in vitro-activated, crawling sperm of the pig intestinal nematode Ascaris suum. It consists of 5-10-nm fuzzy fibers organized into 150-250-nm-thick fiber complexes, which connect to each of the moving pseudopodial membrane projections, villipodia, which in turn make contact with the substrate. Individual fibers in a complex splay out radially from its axis in all directions. The centripetal ends intercalate with fibers from other complexes or terminate in a thickened layer just beneath the pseudopod membrane. Monoclonal antibodies directed against MSP heavily label the fiber complexes as well as individual pseudopodial filaments throughout their length. This represents the first evidence that MSP may be the major filament protein in the Ascaris sperm cytoskeleton. The large fiber complexes can be seen clearly in the pseudopods of live, crawling sperm by computer-enhanced video, differential-interference contrast microscopy, forming with the villipodia at the leading edge of the sperm pseudopod. Even before the pseudopod attaches, the entire cytoskeleton and villipodia move continuously rearwards in unison toward the cell body. During crawling, complexes and villipodia in the pseudopod recede at the same speed as the spermatozoon moves forward, both disappearing at the pseudopod-cell body junction. Sections at this region of high membrane turnover reveal a band of densely packed smooth vesicles with round and tubular profiles, some of which are associated with the pseudopod plasma membrane. The exceptional anatomy, biochemistry, and phenomenology of Ascaris sperm locomotion permit direct study of the involvement of the cytoskeleton in amoeboid motility.