Multiple Worm Research Articles

The Brief Case: the Boy Who Cried Worm.

A 13-year-old, otherwise healthy, male patient living in northeast Ohio presented to the pediatric infectious diseases clinic, reporting to have seen multiple worm segments in his stool during the previous 13 months. With the first occurrence, the specimen was brought to a local urgent care center but was not sent for further identification. The patient was prescribed albendazole (400 mg), with a repeat dose in 2 weeks.

Numerical analysis on bending and contact stress of single and double start worm drive

Worm drives are used for non-parallel transmission of power with reduced noise and vibrations. The proper functioning of a worm drive design depends on number of factors that are to be studied extensively and understood for effective optimization and would help in obtaining a positive relationship between the design parameters and other operating parameters. In this paper, the distribution of bending and contact stress was obtained for a worm wheel design by varying the number of starts and the friction coefficient through Finite Element Analysis (FEA).The worm and worm wheel is modelled for the process parameters obtained from the design considerations and simulation was carried out in ANSYS to determine the stress distribution. The results highlight the development of a higher bending and contact stress distribution for a worm and worm wheel with double start in comparison to a single start worm drive. The bending stress for single and double starts was found to be in a close agreement with the numerically obtained value from Lewis equation, with a maximum observable error of 5%. The present work further highlights the compromise of bending and contact stresses in return for a better efficiency that is inherent in a multiple start worm drive compared to a single start.

Genetic diversity and population structure of Angiostrongylus vasorum parasites within and between local urban foxes (Vulpes Vulpes)

Angiostrongylus vasorum is a nematode parasite of the pulmonary arteries and heart that infects domestic and wild canids. Dogs (Canis familiaris) and red foxes (Vulpes vulpes) are the most commonly affected definitive hosts. Recent studies suggest that angiostrongylosis is an emerging disease, and that red foxes may play an important role in the epidemiology of the parasite. Genetic analyses of parasites collected from dogs and foxes throughout Europe have shown that the same parasite haplotypes are commonly shared between different host species. However, the extent of genetic diversity within local A. vasorum populations and individual hosts is unknown. The objective of the present study was to assess the occurrence of genetic diversity among A. vasorum (a) recovered from different foxes within the Greater London area (a localised population, single worm per fox dataset); and (b) hosted within single foxes (multiple worms per fox dataset). During 2016, A. vasorum worms were collected from foxes culled for other purposes in London. DNA was extracted from each parasite and a partial fragment of the mitochondrial cytochrome oxidase subunit 1 (mtCOI) gene was amplified and sequenced. Sequences from the single worm dataset were compared with those published elsewhere. Combined, 19 haplotypes were described of which 15 were identified from foxes found in London, indicating that considerable genetic diversity can be detected within a local geographic area. Analysis of the multiple worm dataset identified 22 haplotypes defining worms recovered from just six foxes, emphasising the relevance of wild canines as reservoirs of genetic diversity. This is the first study to explore the genetic complexity of individual fox-hosted A. vasorum populations.

Study on the roller enveloping end face internal engagement worm gear

A novel worm gear, named roller enveloping end face internal engagement worm gear, with multiple worm-wheel meshing is proposed to provide multiple outputs with high transmission efficiency and good lubrication for furthering industrial advances. As such, an original worm transmission device with roller enveloping internal end-face meshing was proposed based on the innovation in worm structure and gear meshing theory, which can bear 1–4 working load(s) on a single worm. This paper presents mathematical models of meshing characteristics for roller enveloping end face internal engagement worm gear, including both the contact curve and the tooth profile function based on the gearing meshing theory. In doing so, the tooth profile was calculated by MATLAB and the 3D solid model of worm were produced by Creo to measure the meshing properties of roller enveloping end face internal engagement worm gear. The kinematic simulation was also conducted to analyze meshing position and the corresponding meshing teeth. Our study shows that the overall performance of the original worm transmission device with roller enveloping end face internal meshing is good without any interference, and the output curve is basically consistent with the engaging performance. This study is expected to provide a new multiple outputs worm drive for industry, and the results are beneficial for designers to choose the best parameters.

Optimal design for an end face engagement worm gear with multiple worm-wheel meshing

To solve the problem for lacking a special mechanical transmission that could provide multiple outputs with high transmission efficiency and good lubrication in the modern industrial, a novel worm gear, named end face engagement worm gear, with multiple worm-wheel meshing is proposed for the first time. The essential parameters for the worm gear are optimized to enhance lubrication and meshing properties. Moreover, analysis of variance(ANOVA) is applied to determine the optimum levels and to determine the influence of parameters. The ANOVA results show that the novel end face engagement worm gear with multiple worm wheels provides high lubrication(the lubrication angle is more than 89°) and meshing performance(the induce normal curvature is less than 0.0002 mm−1). The interaction between center distance and roller slant distance most strongly influences the lubrication angle(contributed 51.6%), followed by the parameters of center distance(contributed 25.0%), roller slant distance(contributed 16.4%), tooth angle of gear, gear ratio, and roller radius. In addition, roller radius most strongly influences the induced normal curvature(contributed 39.4%), followed by roller slant distance(contributed 15.2%), tooth angle of the gear(contributed 9.0%), center distance, and gear ratio. The proposed worm gear helps to enrich the no-backlash high precision worm drive and the optimal design method can provide a useful reference on performance improvement of other worm gear.

Epidemics of Multiple Internet Worm Variants and Its Countermee

Epidemics of Multiple Internet Worm Variants and Its Countermee

Two time-delay dynamic model on the transmission of malicious signals in wireless sensor network

Deployed in a hostile environment, motes of a Wireless sensor network (WSN) could be easily compromised by the attackers because of several constraints such as limited processing capabilities, memory space, and limited battery life time etc. While transmitting the data to their neighbour motes within the network, motes are easily compromised due to resource constraints. Here time delay can play an efficient role to reduce the adversary effect on motes. In this paper, we propose an epidemic model SEIR (Susceptible–Exposed–Infectious–Recovered) with two time delays to describe the transmission dynamics of malicious signals in wireless sensor network. The first delay accounts for an exposed (latent) period while the second delay is for the temporary immunity period due to multiple worm outbreaks. The dynamical behaviour of worm-free equilibrium and endemic equilibrium is shown from the point of stability which switches under some threshold condition specified by the basic reproduction number. Our results show that the global properties of equilibria also depends on the threshold condition and that latent and temporary immunity period in a mote does not affect the stability, but they play a positive role to control malicious attack. Moreover, numerical simulations are given to support the theoretical analysis.

Amphetamine Activates an Amine-gated Chloride Channel to Generate Behavioral Effects in Caenorhabditis elegans

Amphetamine is a highly addictive psychostimulant, which is thought to generate its effects by promoting release of dopamine through reverse activation of dopamine transporters. However, some amphetamine-mediated behaviors persist in dopamine transporter knock-out animals, suggesting the existence of alternative amphetamine targets. Here we demonstrate the identification of a novel amphetamine target by showing that in Caenorhabditis elegans, a large fraction of the behavioral effects of amphetamine is mediated through activation of the amine-gated chloride channel, LGC-55. These findings bring to light alternative pathways engaged by amphetamine, and urge rethinking of the molecular mechanisms underlying the effects of this highly-addictive psychostimulant.

Measurement of phenotypic resilience to gastro-intestinal nematodes in Merino sheep and association with resistance and production variables

A cross-over experiment was conducted to compare six different phenotypic measures of resilience to gastro-intestinal nematodes (predominantly Haemonchus contortus) in Merino sheep and their association with resistance and production levels. On each of six farms, 120 ewes born in 2006 and 120 older mixed age ewes were selected at shearing in 2007. Of these, 60 in each mob were serially treated with long-acting anthelmintics to suppress worm populations. The other 60 ewes were managed according to management practices employed on the farm (infected, INF). At shearing in 2008, the experimental sheep had their anthelmintic treatments switched. The experiment concluded at shearing in 2009. Measures of resilience were greasy fleece weight (GFW), live weight gain (LWG) and haematocrit (HCT) when infected and the difference in these variables between infected and suppressed. Resistance was determined from multiple faecal worm egg counts (WEC) when infected. Measures of resilience based on GFW, LWG and HCT were moderately correlated with each other (r=0.25–0.50) suggesting that they represent different traits. Correlations between a measure in infected animals, and the difference in the same measurement between infected and uninfected animals were higher (r=−0.37 to −0.82), indicating that measurement during infection is an adequate measure of resilience. WEC was negatively correlated with LWG and HCT during infection but not GFW. Correlations with resilience measures based on difference between infected and uninfected were positive. Surviving infected sheep were found to have higher haematocrit (HCT), and lower WEC in summer and autumn than sheep that died following the measurement. These results show that measurement of performance traits while infected is a reasonable approximation of measurement of resilience based on the difference in performance between infected and non-infected. They also show that resilience to worm infection is not a single trait, but rather a suite of moderately correlated traits.

Locomotion of C. elegans: A Piecewise-Harmonic Curvature Representation of Nematode Behavior

Caenorhabditis elegans, a free-living soil nematode, displays a rich variety of body shapes and trajectories during its undulatory locomotion in complex environments. Here we show that the individual body postures and entire trails of C. elegans have a simple analytical description in curvature representation. Our model is based on the assumption that the curvature wave is generated in the head segment of the worm body and propagates backwards. We have found that a simple harmonic function for the curvature can capture multiple worm shapes during the undulatory movement. The worm body trajectories can be well represented in terms of piecewise sinusoidal curvature with abrupt changes in amplitude, wavevector, and phase.

Surgical complications of Ascaris lumbricoides in children

Aim:To report the surgical complications of Ascaris lumbricoides infestation in children.Materials and Methods:This is a retrospective study and cases of intestinal ascariasis managed conservatively were excluded.Results:Sixteen children presented with Ascariasis sequelae, which included ileal volvulus (n=5), perforations (n=4), intussusception (n=1), biliary ascariasis (n-1) and impacted multiple worm boluses (n=5). Plain abdominal radiographs showed pneumoperitoneum (3), cigar bundle appearance (3) and multiple air and fluid levels (13). Sonography showed floating worms with free fluid (2), sluggish peristalsis and moderate free fluid (7) and intestinal worm bolus (11). The surgical procedures included milking of worms (in all), bowel resection (6), closure of perforation (3) and manual reduction of intussusception (1). Biliary ascariasis was managed conservatively and the progress monitored with sonography. There were 3 deaths all of whom had intestinal volvulus, bowel necrosis and toxemia.Conclusion:Sonography can be helpful in diagnosing the presence of worms, its complications and in evaluating response to treatment. Early surgical intervention in those with worm bolus, peritonism, and volvulus may salvage bowel and reduce mortality.

Intestinal intussusception due to concurrent infections with <i>Hymenolepis nana</i> and <i>Dentostomella translucida</i> in an African giant rat (cricetomys gambianus). A case report

A rare case of intestinal intussusception due to multiple worm infections ( Hymenolepis nana and Dentostomella translucida ) was observed in an African giant rat ( Cricetomys gambianus , Waterhouse, 1840). The condition was observed as an incidental finding before an experimental dissection of the animals in the Department of Veterinary Anatomy, University of Agriculture Abeokuta, Nigeria. The rat was anorexic and depressed with rough hair coat, and died before the commencement of the experiment. Grossly, the intussusception was 7 cm in length and 27 cm caudal to the stomach and 81cm to the ileo-caecal junction. The affected part of the small intestine was moderately distended with worms and the associated mesenteric blood vessels were engorged. Microscopically, worms ( H. nana and D. translucida ) were observed in the lumen of the intestine with severe cellular infiltration mostly eosinophils, neutrophils and macrophages. Eggs of both worms, at different stages of development and a focus of attachment of the worms were observed on the intestinal mucosa. The zoonotic implications of these worms were discussed especially H. nana . This report appears to be the first reported case of intestinal intussusception due to multiple helminth infections in an African giant rat. KEYWORDS: Hymenolepis nana, Dentostomella translucida , Intestinal intussusception, African giant rat.

Prevalence of intestinal worm infections among primary school children in Nairobi City, kenyA.

The main objective of the study was to determine the prevalence of total, single and multiple intestinal worm infections among the primary school children in Nairobi City. A cross-sectional descriptive study was used to determine the status of intestinal worm infections whose subjects were drawn from eight city administrative divisions. Proportional random sampling method to select forty five (45) schools out of 320 public, private and non-formal schools was used. Using the school enrolment register for standard 3 and 4, fifty (50) pupils per school were selected to participate in the study. Quantitative data from the study subjects were collected by use of a structured questionnaire. In addition, stool specimens were collected from each study subject and examined by Kato-Katz laboratory method. The four intestinal worms investigated constituted a total prevalence of 12.9%. This prevalence was found to be lower than that in two other previous studies. A. lumbricoides had the highest prevalence and S. mansoni had the lowest. Prevalence of single worm infections constituted 8.6% of the total prevalence. Differences in prevalence between males and females were observed only with respect to T. trichiura and hookworm species. Fourteen to sixteen (14-16) and 11-13 years of age groups had the highest total prevalence of 47% and 30.6% respectively. Differences in prevalence were not found among the school categories with exception of T. trichiura infections. Prevalence of total, single ahd multiple infections showed a downward trend when compared to the previous studies with Ascaris lumbricoides persisting with the highest prevalence.

Intensity of Intestinal Infection with Multiple Worm Species Is Related to Regulatory Cytokine Output and Immune Hyporesponsiveness

Increasing immunological dysfunction (atopy and autoimmunity) in western society may be linked to changes in undetermined environmental agents. We hypothesize that increased exposure to multiple gut worm species promotes stronger immunological regulation. We report here that African children constitutively secrete more immunoregulatory cytokines (interleukin [IL]-10 and transforming growth factor [TGF]- beta1) under conditions of hyperendemic exposure to the intestinal nematodes Ascaris lumbricoides and Trichuris trichiura, compared with conditions of mesoendemic exposure. Under conditions of hyperendemic exposure, estimators of combined intestinal nematode infection level relate positively to combined constitutive IL-10 and TGF-beta1 production and negatively to total immune reactivity (determined as IL-4, interferon-gamma, and cellular proliferative responses to Ascaris or Trichuris helminth antigens, Streptococcus pneumoniae bacterial antigen, or the mitogen phytohemaglutinin). Total immune reactivity and anti-inflammatory cytokine production relate inversely. Our data suggest that gut nematodes are important mediators of immunoregulation.

PRESIDENTIAL ADDRESS: THE ROLE OF VARIATION IN HOST-PARASITE INTERACTIONS: LINKING GENETIC DEMES AND LIFE HISTORY SCHEMES

PRESIDENTIAL ADDRESS: THE ROLE OF VARIATION IN HOST-PARASITE INTERACTIONS: LINKING GENETIC DEMES AND LIFE HISTORY SCHEMES

Evaluation of recombinant chitinase and SXP1 antigens as antimicrofilarial vaccines.

Prior studies indicate that a microfilarial stage-specific chitinase is a possible candidate antigen for a transmission-blocking vaccine against Brugian filariasis. The antigen is a functional enzyme that progressively appears as microfilariae mature and become able to infect and develop in a susceptible mosquito vector. It is recognized by a monoclonal antibody that reduces microfilaremia in infected animals and by a subset of sera from infected persons who remain amicrofilaremic. Immunization of jirds with recombinant chitinase induced partial protection against microfilaremia resulting from subsequent infection with Brugia malayi, but did not reduce adult worm burdens. Vaccination was much less effective when administered during the prepatent stage of infection and was ineffective when given to microfilaremic jirds. The protective epitope appears to be located close to the carboxy terminus of the chitinase molecule. Immunization of jirds with SXP1, an antigen present in multiple worm stages, also reduced microfilaremia and, in some experiments, adult worm burdens, but hyperimmunization with a recombinant filarial myosin was not protective. These observations indicate that the relative timing of immunization and infection is an important factor in the efficacy of antimicrofilarial vaccines.

Population Dynamics of Pomphorhynchus bulbocolli in Gammarus pseudolimnaeus

The population dynamics of larval Pomphorhynchus bulbocolli were studied in the amphipod intermediate host, Gammarus pseudolimnaeus. Amphipods were collected monthly from April 1982 to March 1983 from a study site at the West Fork of Drake's Creek, Simpson Co., Kentucky. The number of infected amphipods per m2 was lowest (0.6) in May and highest (27.3) in November. A total of 2,502 amphipods was examined; 1,575 (62.9%) were infected with P. bulbocolli. Infection intensity ranged from 1 to 12 with a mean of 1.83 +/- 0.03. Single and multiple worm infections were found in 800 (50.8%) and 775 (49.2%) amphipods, respectively. Female amphipods had higher prevalence and intensity of infections than males but differences were not significant. Prevalence in the monthly samples was lowest in May (5.1%) and highest in October (88.1%). The monthly mean intensity of infection was lowest in July (1.10 +/- 0.04) and highest in November (2.02 +/- 0.08). Amphipods in length classes 3 through 15 were infected with P. bulbocolli. In late summer and fall, amphipods in all length classes were infected, while in late winter and spring only large amphipods were infected. Recruitment of P. bulbocolli into amphipods was seasonal and the total infrapopulation within an amphipod was usually acquired at one time. There was little correlation between size and number of larvae present.

The diurnal migration of the fowl cestode, Raillietina cesticillus.

R. cesticillus was found to undergo a diurnal migration in both multiple and single worm infections of the fowl. This migration involved movement of both scoleces and strobilae and occurred in an anterior direction when the intestine was empty of food, and in a posterior direction when the intestine contained food. The relevance of the migration to the histological picture of the worm in situ is discussed and some possible explanations for the migration are suggested.

Studies on the Reproductive System of Hymenolepis diminuta Using Autoradiography and Transplantation

Adult Hymenolepis diminuta exposed in vitro for 3 hr to 3H-thymidine showed incorporation of the isotope on autoradiograms over nuclei of actively dividing cells in the testes, ovary, vitellaria, and developing embryos in the eggs. Timing studies utilizing labeled worms transplanted to uninfected hosts showed that it took 18 hr for spermatogonia to develop to primary spermatocytes, 24 hr to secondary spermatocytes, 36 hr to spermatids, and 48 hr to sperm bundles. Self-insemination was confirmed in single worm transplants of 3 days by the presence of labeled sperm in the seminal receptacles. In multiple worm transplants labeled worms inseminated themselves in each case and cross-inseminated with 92% of the unlabeled worms present.

Treatment of multiple intestinal worm infections with piperazine citrate.

SummaryNinety-five Honduran laborers with multiple intestinal worm infections were treated with piperazine citrate liquid or capsules. Eighty (94 per cent) of 85 men with Ascaris lumbricoides infections were cured, many of them on only 2.0 grams in a single daily dose for 3 days. The drug seemed to have little effect against Trichuris trichiuris in the dosages employed, and no effect against Necator americanus. No toxicity was observed.