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At least 145 records · Page 8Linked to original sources
PubMed1997

An outbreak of ascariasis with marked eosinophilia in the southern part of Kyushu District, Japan, caused by infection with swine ascaris.

Ascariasis has been a representative soil-transmitted intestinal parasitic disease in warm climates. In Japan, this disease was a major and serious public health problem only a few decades ago. However, the incidence of the disease nowadays is reportedly less than 0.01%. Recently in 1994 through 1995, we experienced a total of 14 cases who were suspected as having ascariasis. They were characterized by peripheral blood eosinophilia (30-70%), high serum titers against Ascaris antigen, and most notably, they were absolutely negative for Ascaris eggs in repeated fecal examinations. Specific antibody titers against Ascaris antigen correlated well with the degree of eosinophilia. All patients were living in narrow areas of Kyushu, Japan, where a lot of porcine farms were located. Most of the patients were asymptomatic and pointed out to have eosinophilia during follow-up studies of chronic diseases or in regular check-up. Only one patient had a clear sign of Löffler's syndrome and another had subcutaneous eosinophilic granuloma. However, laboratory examinations revealed moderate liver dysfunction in 7 patients and pulmonary infiltrations in 5 patients. Based on circumstantial and serological evidence, these patients were diagnosed as having been infected with Ascaris lumbricoides suum, a swine Ascaris.

Adult↗
PubMed1984

Methods to evaluate nutritional and economic implications of Ascaris infection.

Ascaris infection has important economic implications for human populations, due to its negative effects on growth of undernourished children and its less common role in causing intestinal obstruction. The deleterious effects of Ascaris infection on growth of undernourished children have been demonstrated in studies conducted in India, Kenya and Tanzania; deworming has resulted in improved weight gains of 20-35% compared with uninfected children. However other studies in Ethiopia, Bangladesh and Guatemala have not found statistically significant improvements in growth of children after treatment for Ascaris infection, most likely due to inadequacies in choice of population, sample size, experimental design, data analysis and/or relative failure of drug treatment. Field studies which attempt to measure the magnitude of growth deficits due to Ascaris must take the following into account: (1) rapidly growing preschool age children from communities with a high prevalence of protein-energy malnutrition are the most important group to study. (2) A longitudinal design, preferably using randomly allocated treatment and placebo groups, is highly desirable. (3) A sufficient period of time for growth improvement must be allowed between the beginning of the intervention and final measurements. (4) The sample sizes necessary to test hypotheses adequately should be calculated in advance. (5) The drug chosen for treatment of Ascaris should produce high cure rates and reinfection rates should be determined. Possible effects of the drug on other diseases prevalent in the population should be considered in the data analysis. (6) Evaluation of worm loads are very important in interpretation of results. (7) The data analysis must be appropriate for the individual study and must be designed to consider confounding factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2004

[Ascaris-induced acute pancreatitis].

AIM OF THE STUDY: To indicate options in a surgical university team in Vietnam for treatment of ascaris-induced acute pancreatitis. PATIENTS AND METHODS: From January 1998 to April 2001, 33 patients (mean age 46 years) were admitted with a diagnosis of acute pancreatitis based on elevated serum amylase in 29 patients (88%), and elevated urinary amylase in all patients and a compatible clinical picture. The pancreatic ultrasonography was abnormal in 79% of cases. Biliary and pancreatic ultrasonography shown ascaris in 31 patients (94%). In other two patients ascaris was detected with duodenal endoscopy. RESULTS: In 24 patients, the worms from the duodenum and/or across the ampullary orifice was trapped and withdrawn during duodenoscopy and failed in three patients. Nine patients were operated on, three after failure of endoscopic treatment, five for lithiasis of the common bile duct associated to the ascariasis, and one for necrotic pancreatitis. Seven patients operated on underwent a choledocotomy with a T-tube drainage, two patients underwent a left pancreatectomy to withdraw the ascaris, and one patient a resection of pancreatic necrosis. All patients recovered without complications except the patient with a necrotic pancreatitis who developed a pancreatic fistula for 23 days. Mean discharge times were 5.6 days after endoscopic treatment and 12.2 days after surgery. Effective antihelminthic therapy was administered in all patients. CONCLUSION: Endoscopic treatment was effective in 24 out of 33 patients. Surgery was indicated for failures of endoscopic treatment, association of ascariasis and common bile duct stones, migration of ascaris in intra pancreatic duct, and pancreatic necrosis.

Acute Disease↗
PubMed1980

Relationships between Ascaris infection and growth of malnourished preschool children in Kenya.

A longitudinal study in Ascaris-infected and noninfected children was conducted in two Kenyan villages. Anthropometric, clinical, and stool exams were performed three times at 14-week intervals. All children received an anthelmintic drug (levamisole) at the second examination. In the 14 weeks before deworming, children with Ascaris (n = 61) did not differ from controls (n = 125) in percentage expected weight gain. In the 14 weeks after deworming, previously infected children showed higher percentage expected weight gain than controls. Before deworming, there was a statistically significant (P less than 0.0005) decrease in triceps skinfold thickness in Ascaris-infected children versus controls. After deworming, skinfold increased significantly (P less than 0.0005) in previously infected children versus controls. Multiple regression analysis showed that Ascaris infection was by far the most important variable of those studied explaining decrease in skinfold thickness before and increase after deworming. It appears that even light Ascaris infections might adversely influence nutritional status, and deworming might enhance growth.

Anthropometry↗
PubMed1984

Lactose maldigestion in Ascaris-infected preschool children.

Two studies were conducted to investigate the contribution of Ascaris lumbricoides to lactose maldigestion in preschool children in two different communities in Panama where milk is available as a source of nutrients and the prevalence of Ascaris is known to be high. Both Ascaris-infected and uninfected children were given a standard lactose load and lactose absorption was studied by measuring the rise in plasma glucose in study 1 and by determination of breath hydrogen concentrations at regular intervals after ingestion of the test dose in study 2. All children were tested before anthelmintic treatment with levamisole and 3 wk after therapy. The mean rise in blood glucose from infected (n = 13) children 40 min after the ingestion of lactose was about half of that of the controls (n = 21). After deworming, lactose digestion improved in previously infected children. In study 2, significant differences in breath hydrogen concentrations postmilk ingestion were observed between the Ascaris-infected (n = 47) and the uninfected children (n = 35) before treatment. There was a substantial reduction of breath hydrogen after milk ingestion in the previously infected children after therapy. No differences were observed in breath hydrogen content of the uninfected children during the pre- and posttreatment phases of the study in the lactose tolerance test. These studies provide evidence that infection with Ascaris lumbricoides impairs lactose digestion in preschool children.

Ascariasis↗
PubMed1991

Fetal response to maternal ascariasis as evidenced by anti ascaris lumbricoides IgM antibodies in the cord blood.

The immune response of the fetus to maternal infection with Ascaris lumbricoides was studied by estimating IgG and IgM antibodies, using ELISA, in 28 paired samples of mother and cord blood. A. lumbricoides adult male, cuticle and unembryonated egg antigen was used. Toxocara canis larva antigen was used as a specificity control. Presence of IgG in the cord blood does not signify fetal response, but the presence of IgM antibodies does. IgM antibodies to Ascaris adult male antigen were present in 27 out of 28 maternal sera and 1 out of 28 cord sera. All maternal sera and only 6 cord sera showed IgM antibodies against Ascaris cuticle and 20 out of 22 maternal sera and 8 out of 22 cord sera tested, showed IgM antibodies to Ascaris unembryonated egg antigen. Sixteen out of 22 maternal sera and none out of 22 cord sera showed IgM antibody against Toxocara canis antigen, ruling out cross reaction and transplacental leak. The results of our study suggest that the Ascaris infection can spread to the fetus and elicit immune response.

Antibodies, Helminth↗
PubMed1970

[The experiments on the infectivity to mice of the Ascaris eggs irradiated with Cobalt(60)]

In order to find out a valuable control measure for soil-transmitted parasties, the infectivity in mice of Ascaris eggs irradiated with Cobalt(60) were examined. The results were summarised as follows. In vitro, Ascaris eggs irradiated with larger doses of Cobalt(60) developed poorly, and no difference was found between fresh eggs and those cultured for a few days. Ascaris eggs irradiated with doses of 200,000 rad. developed at the rate of 90 percent after 4 weeks, whereas those irradiated with 1,000,000 rad. developed 28 percent. Ascaris eggs irradiated with Cobalt(60) after 2 weeks of culture were poor in development compared with those of 4 week culture. Eggs cultured for 5 weeks showed weaker infectivity in mice than those cultured for 8 weeks. In the control groups, the infectivity in mice of Ascaris eggs was remained the same between 5 and 8 weeks. The minimum dose of Cobalt(60) irradiation effective for preventing infectivity in mice was estimated to be 200,000 rad.

Journal Article↗
PubMed1994

The molecular structure of the complex of Ascaris chymotrypsin/elastase inhibitor with porcine elastase.

BACKGROUND: The intestinal parasitic worm, Ascaris suum, produces a variety of protein inhibitors that defend the organism against the host's proteinases. Eight different proteins from Ascaris suum have been identified as inhibitors of serine proteinases, targeting chymotrypsin, elastase and trypsin. These inhibitors share 30-40% sequence identity with one another, but have virtually no sequence identity with members of any of the other families of serine proteinase inhibitors. RESULTS: The crystal structure of the complex of porcine pancreatic elastase with a chymotrypsin/elastase inhibitor from Ascaris suum (the C/E-1 inhibitor) has been solved to 2.4 A resolution by the molecular replacement method. The C/E-1 inhibitor exhibits a novel folding motif. There are only two small beta-sheets and two single-turn 3(10)-helices in this inhibitor. Unlike the majority of proteins, the C/E-1 inhibitor does not have a hydrophobic core. The presence and unique topography of the five disulfide bridges suggests that they play important roles in maintaining the tertiary structure of the inhibitor. In addition, the side chains of several charged residues from electrostatic and hydrogen-bonding cascades, which also probably compensate for the lack of extensive secondary structures and a hydrophobic core. The reactive-site loop of this inhibitor displays a conformation that is characteristic of most serine proteinase inhibitors. CONCLUSIONS: The structure of the C/E-1 inhibitor confirms that inhibitors from Ascaris suum belong to a novel family of proteinase inhibitors. It also provides conclusive evidence for the correct disulfide bridge connections. The C/E-1 inhibitor probably acts by a common inhibitory mechanism proposed for other substrate-like protein inhibitors of serine proteinases. The unusual molecular scaffolding presents a challenge to current folding algorithms. Proteins like the C/E-1 inhibitor may provide a valuable model system to study how the primary sequence of a protein dictates its three-dimensional structure.

Amino Acid Sequence↗
PubMed2006

Antibody responses to Ascaris-derived proteins and glycolipids: the role of phosphorylcholine.

In addition to proteins, glycolipids can be targets of antibody responses and contribute to host-pathogen interaction. Following the structural analysis of Ascaris lumbricoides-derived glycolipids, the antibody responses of a group of children with no, light and heavy infections were analysed. The role of the phosphorylcholine moiety, present on Ascaris glycoproteins and glycolipids, in antibody reactivity of these infected individuals was determined. Children carrying heavy infections showed highest IgG reactivity to glycolipids compared to lightly or non-infected children. Substantial IgG antibody reactivity to both (glyco)proteins and glycolipids was found to be directed to the phosphorylcholine moiety as determined by either removal of this group or a competition assay. This was most pronounced for glycolipids, where removal of the phosphorylcholine moieties by hydrofluoric acid treatment abrogated IgG antibody reactivity. Measurement of IgG4 and IgE isotypes showed no IgG4 reactivity to Ascaris glycolipids, but raised IgE responses were detected in subjects with light or no Ascaris infections, suggesting that IgE responses to glycolipids may play a role in controlling parasite burden. Differences found in antibody profiles to glycolipids and (glyco)proteins, indicate that these different classes of compounds may have distinct roles in shaping of and interacting with humoral immune responses.

Animals↗
PubMed1996

Heterogeneity of cholecystokinin/gastrin-like immunoreactivity in the nervous system of the nematode Ascaris suum.

A wholemount immunocytochemical method was used for the localization of cholecystokinin (CCK8)-like and gastrin-like immunoreactivity in Ascaris. The patterns of specific neuronal staining given by two antisera and four monoclonal antibodies made against CCK8, and one antiserum made against gastrin were investigated. Preabsorption of these antibodies with CCK8 or gastrin 17 resulted in complete loss of immunoreactivity in almost all of the neurons (two antisera also contained nonspecific antibodies), suggesting that all of the antibodies recognize epitopes, in Ascaris neurons, that include some or all of the C-terminal five amino acids that are identical in CCK8 and gastrin 17. However, the seven different antibodies showed immunoreactivity in different subpopulations of neurons, implying that there are at least seven different species of CCK-like molecules in Ascaris. Fractionation of Ascaris peptide extracts by high performance liquid chromatography (HPLC), monitoring fractions with a CCK8 radioimmunoassay (RIA), also shows heterogeneity of molecules immunologically related to CCK8.

Animals↗
PubMed1989

Retrovesicular ganglion of the nematode Ascaris.

The nematode nervous system is distinguished by the small number and morphological simplicity of its neurons. Recently, the shapes and synaptic interactions of each of the 302 neurons in the small free-living nematode, Caenorhabditis elegans, have been determined from reconstructions of serial sections by electron microscopy. Comparable anatomical studies of the large parasitic nematode Ascaris have concentrated on the dorsal and ventral nerve cords where reconstructions of motor neurons by light microscopy led to the identification of seven distinct types of motor neurons, each corresponding to a homologous cell type in C. elegans. In this study the shapes of the 13 neurons with cell bodies in the retrovesicular ganglion (RVG) of Ascaris suum were reconstructed from light micrographs of serial sections. In other preparations the morphology of RVG neurons was observed in whole mounts after the cells were impaled with microelectrodes and injected with the fluorescent dye Lucifer yellow. The intracellular electrodes also permitted electrical recordings and revealed that one type of cell, the AVF-like interneuron, expresses spontaneous repetitive plateau potentials. Comparisons of neuronal morphologies in the retrovesicular ganglia of Ascaris and C. elegans suggest that each neuron in Ascaris can be assigned a corresponding homolog in C. elegans. These data provide further evidence for a remarkable conservation of neuronal morphology in nematodes despite large differences in size and habitat.

Action Potentials↗
PubMed1997

In vivo and in vitro studies on the sonographical detection of Ascaris lumbricoides.

Intestinal ultrasound, a frequently applied diagnostic tool in industrialized nations, has recently also been introduced in tropical regions. This study attempts to describe the anatomical and sonographical features of Ascaris lumbricoides in the human intestine. In the course of a schistosomiasis morbidity study in Madagascar, 581 inhabitants of a rice-farming village on the high plateau of the island had their stools examined by means of a modified Kato-Katz thick smear technique (four slides per sample); 53% had eggs of Ascaris lumbricoides in their stools. Twenty-two individuals underwent intestinal ultrasound examination and, in six cases, Ascaris lumbricoides was visualized. All six patients showed eggs upon stool examination. At ultrasound, the parasite was seen as a large, curved echogenic strip (4-6 mm in diameter) with an inner, anechoic, longitudinal canal. The image resembled a winding highway, the central structure representing the pseudocoel of the parasite. Patients were treated with mebendazole. The excreted worms of one patient were scanned under water, showing the same characteristics as in vivo. We conclude that Ascaris lumbricoides has a characteristic sonographical appearance and should not be a confounding factor in studies using intestinal ultrasound.

Aged↗
PubMed1983

2-Methylacetoacetyl-coenzyme A reductase from Ascaris muscle: purification and properties.

2-Methylacetoacetyl-CoA and 3-keto-2-methyl pentanoyl-CoA have been proposed to be intermediates in the synthesis of 2-methylbutyrate and 2-methylvalerate, respectively, by Ascaris lumbricoides muscle. These volatile acids are major fermentation products of Ascaris metabolism. 2-Methylacetoacetyl-CoA reductase has been purified 532-fold from Ascaris muscle to yield a homogeneous preparation which contained a single protein species as observed on discontinuous polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The purification procedure utilized subcellular fractionation, affinity chromatography on NAD+ agarose, and ion-exchange chromatography on DEAE-cellulose. A constant activity ratio for ethyl 2-methylacetoacetate and acetoacetyl-CoA was observed during purification, indicating that the same enzyme catalyzed both reactions. In addition, the purified protein catalyzed the NADH-dependent reduction of ethyl-3-keto-2-methyl pentanoate at essentially the same rate as it did ethyl 2-methylacetoacetate. The purified enzyme is a basic protein with an isoelectric point of 8.45 at 4 degrees C. The molecular weight of the native protein (Mr = 64,000 by exclusion chromatography) and the size of the subunit (Mr = 30,000 by dodecyl sulfate-polyacrylamide electrophoresis) indicate that the enzyme is composed of two subunits of the same molecular weight. Substrate-specificity studies, undertaken with the purified protein, demonstrated that the ethyl esters can substitute for the coenzyme A derivatives but this substitution results in an active substrate only when a branched 2-methyl group is present. The straight-chain ethyl ester is inactive. Kinetic constants for the substrates and nucleotides were determined. The role of the CoA esters as the physiological substrates for the Ascaris enzyme is substantiated. When assayed in the reductive direction with ethyl 2-methylacetoacetate as substrate, the activity of the purified enzyme was inhibited not only by coenzyme A as previously reported, but also by acetyl-CoA. The physiological implications of these inhibitions are discussed.

Alcohol Oxidoreductases↗
PubMed1991

Propionyl-CoA condensing enzyme from Ascaris muscle mitochondria. I. Isolation and characterization of multiple forms.

The condensation of two propionyl-CoA units or a propionyl-CoA with acetyl-CoA is required for the synthesis of 2-methylvalerate or 2-methylbutyrate, respectively, two of the major fermentation products of Ascaris anaerobic muscle metabolism. An enzyme that preferentially catalyzes the condensation of propionyl-CoA rather than acetyl-CoA has been purified from the mitochondria of the parasitic intestinal nematode Ascaris lumbricoides var. suum. The purified enzyme is over 10 times more active with propionyl-CoA than with acetyl-CoA as substrate. It also catalyzes the coenzyme A-dependent hydrolysis of acetoacetyl-CoA at a rate four times higher than the propionyl-CoA condensation reaction. The purified Ascaris condensing enzyme preferentially forms the 2-methyl-branched-chain keto acids rather than the corresponding straight chain compounds. The native molecular weight of the purified enzyme was estimated to be 160,000 by gel filtration chromatography and 158,000 by high pressure liquid chromatography. The enzyme migrated as a single protein band with Mr 40,000 during sodium dodecyl sulfate-polyacrylamide electrophoresis, indicating that the enzyme is composed of four subunits of the same molecular weight. Chromatography on CM-sephadex resulted in the isolation of two separate peaks of activity, designated as A and B. Both A and B had the same molecular weight and subunit composition. However, they differed in their specific activities and isoelectric points. The pIs of condensing enzymes A and B were 7.6 and 8.4, respectively. Propionyl-CoA was the best substrate for the condensation reaction with both enzymes. However, the specific activity of enzyme B for both propionyl-CoA condensation (3.4 mumol/min/mg protein) and acetoacetyl-CoA thiolysis (13.8 mumol/min/mg protein) was 2.4 times higher than that obtained with enzyme A. Similarly, chromatography on phosphocellulose resolved the Ascaris condensing enzyme activity into one minor and two major peaks. All of these components had the same molecular weight and subunit composition, but differed in their specific activities. The two major phosphocellulose peaks cross-reacted immunologically when examined by the Ouchterlony double immunodiffusion technique. In addition, antiserum against the phosphocellulose most active form cross-reacted with forms A and B isolated by chromatography of the enzyme on CM-Sephadex, indicating that all forms were immunochemically related.

Alcohol Oxidoreductases↗
PubMed1991

Propionyl-CoA condensing enzyme from Ascaris muscle mitochondria. II. Coenzyme A modulation.

The propionyl-CoA condensing enzyme which catalyzes the first step in the biosynthesis of 2-methylbutyrate and 2-methylvalerate by Ascaris muscle appears to exist in at least three forms in the mitochondria of this parasitic nematode. Two forms, A and B, were separated by ion exchange chromatography on CM-Sephadex. Chromatography on phosphocellulose resulted in the recovery of one minor peak (I) and two major peaks with activity (II and III). A and B as well as I, II, and III differed in their specific activities. Forms B and III were the most retained by their resins, and were the most active forms of the enzyme in each case. Inhibition studies with metabolites from Ascaris mitochondria indicate that CoASH, a product of the condensation reaction, and acetyl-CoA are effective inhibitors of the condensing and thiolytic activities of the Ascaris enzyme, respectively. Incubation of the active enzyme form B for 2 h with 0.1 mM CoASH at room temperature under nitrogen caused the loss of 92% of the propionyl-CoA condensing activity and 67% of the thiolase activity when assayed in standard mixtures. The propionyl-CoA condensing enzyme exhibited a hyperbolic dependence of the condensation velocity to changes in substrate concentration. However, in the presence of CoASH the Michaelis-Menten kinetics was transformed into a sigmoidal kinetics indicating a deviation from a simple product inhibition. Inactivation of the most active forms of the enzyme with CoASH was accompanied by (a) a change in the chemical reactivity of the protein toward p-chloromurcuribenzoate, (b) a change in the uv-visible spectrum of the protein, and (c) a change in the elution patterns from both CM-Sephadex and phosphocellulose column chromatography, where-upon one, two, or more protein peaks were obtained. The several protein peaks resolved by rechromatography of the [14C]CoASH-inactivated enzyme III on phosphocellulose had different CoASH contents. The elution positions were correlated with the less active forms (I and II) having increased [14C]CoASH activities. Similarly, the two peaks isolated upon rechromatography of the CoASH-partially inactivated enzyme B on CM-Sephadex had different isotope contents and the elution position of enzyme A corresponded to the less active form. The results described indicate that the CoASH modification of Ascaris propionyl-CoA condensing enzyme may be responsible for the existence of several forms of the enzyme and might represent a mode of control by chemically modulating the amount of the active forms of the enzyme.

Acetyl-CoA C-Acetyltransferase↗
PubMed1986

Electron-transfer complexes of Ascaris suum muscle mitochondria. II. Succinate-coenzyme Q reductase (complex II) associated with substrate-reducible cytochrome b-558.

A succinate-coenzyme Q reductase (complex II) was isolated in highly purified form from Ascaris muscle mitochondria by detergent solubilization, ammonium sulfate fractionation and gel filtration on a Sephadex G-200 column. The enzyme preparation catalyzes electron transfer from succinate to coenzyme Q1 with a specific activity of 1.2 mumol coenzyme Q1 reduced per min per mg protein at 25 degrees C. The isolated complex II is essentially free of NADH-ferricyanide reductase, reduced CoQ2-cytochrome c reductase and cytochrome c oxidase and consists of four major polypeptides with apparent molecular weights of 66 000, 27 000, 12 000 and 11 000 and two minor ones with Mr of 36 000 and 16 000. The complex II contained cytochrome b-558, a major constituent cytochrome of Ascaris mitochondria, at a concentration of 3.6 nmol per mg protein, but neither other cytochromes nor quinone. The cytochrome b-558 in the complex II was reduced with succinate. In the presence of Ascaris NADH-cytochrome c reductase (complex I-III) (Takamiya, S., Furushima, R. and Oya, H. (1984) Mol. Biochem. Parasitol. 13, 121-134), the cytochrome b-558 in complex II was also reduced with NADH and reoxidized with fumarate. These results suggest the cytochrome b-558 to function as an electron carrier between NADH dehydrogenase and succinate dehydrogenase in the Ascaris NADH-fumarate reductase system.

Animals↗
PubMed1986

Neither a germ line-specific nor several somatically expressed genes are lost or rearranged during embryonic chromatin diminution in the nematode Ascaris lumbricoides var. suum.

Ascaris lumbricoides var. suum is a parasitic nematode of pigs. Its embryos undergo chromatin diminution between the third and fifth cleavages, resulting in the loss of about 30% of the DNA from all somatic precursor cells while the germ line DNA stays intact. Most of the eliminated DNA has been shown to be satellite sequences. Theodor Boveri [(1910) In "Festschrift fur R. Hertwig, III," Vol. 3, pp. 131-214, Fischer] proposed that functions essential only to the germ line might be lost from the soma. We have examined this proposal by cloning a gene encoding the major sperm protein (MSP) using a cloned MSP gene from Caenorhabditis elegans as a probe. The MSP appears to be expressed only in the testis of Ascaris, as it is in Caenorhabditis. Actin and alpha tubulin were also cloned to serve as somatically expressed gene controls. By probing Southern blots of somatic and germ line DNA with these cloned genes, it was found that none of them was lost or rearranged during chromatin diminution. Thus at least one germ line-specific gene is neither lost nor rearranged during chromatin diminution. We also found that the two nematode species differ widely in their numbers of both MSP and actin genes. Caenorhabditis has greater than 30 MSP genes, but Ascaris has no more than three; whereas Ascaris has many more actin genes than Caenorhabditis.

Actins↗
PubMed1984

Epidemiology and transmission dynamics of Ascaris lumbricoides in Okpo village, rural Burma.

A horizontal study of the prevalence of Ascaris infection was carried out on the total population of Okpo village near Rangoon, Burma, where a similar study had been conducted 13 years earlier. Ascaris eggs in faeces were counted after treatment with levamisole on a random sample of 50% of the infected population to give information to the numbers of epg of stool, the mean worm burden per host and the distribution of worms in the community. The information on prevalence is compared with that of the previous survey. Various population parameters of Ascaris were calculated to estimate the transmission dynamics of A. lumbricoides. In addition, chemotherapeutic regimes, assessed on the proportion of the human population to be treated and the time interval between treatments, are proposed to reduce transmission below a critical threshold. The findings are compared with those of other studies and the probable mode of occurrence and maintenance of Ascaris infection in Okpo village are discussed.

Adolescent↗