Intestinal Helminthic Infections Diagnosed by Colonoscopy in a Regional Hospital during 2001-2008

The present study investigated characteristics of 24 parasite infection cases detected during colonoscopy in a regional hospital from January 2001 to December 2008. Sixteen patients were confirmed with Trichuris trichiura infection, 6 patients were with Ascaris lumbricoides infection, 1 patient with Enterobius vermicularis infection, and 1 patient with Anisakis infection. Among them, 7 patients (43.8%) were asymptomatic. Colonoscopy findings were normal in 18 patients (75.0%). Among the patients with T. trichiura infection, colonoscopy showed several erosions in 2 patients (8.3%) and non-specific inflammation of the affected segment of the colon in 3 patients (12.5%). In 1 patient with anisakiasis, colonoscopy revealed a markedly swollen colonic wall. Stool examinations were performed before treatment in 7 patients (29.2%) and were all negative for parasite eggs or worms. These results suggest that colonoscopy is a useful diagnostic approach for parasitic infections even for asymptomatic patients and for patients with negative stool examinations.     

A successful experience of soil-transmitted helminth control in the Republic of Korea

Soil-transmitted helminths (STH), namely Ascaris, Trichuris and hookworms (Ancylostoma and Necator), present a global health problem to about a half of the earthos population. In the Republic of Korea, STH were highly prevalent and were considered a high priority target for national control. To promote the control, a non-governmental organization named Korea Association for Parasite Eradication (currently Korea Association of Health Promotion) was founded in 1964, and mass fecal examination followed by selective mass chemotherapy with anthelmintics was performed twice a year from 1969 to 1995 targeting whole nationwide schoolchildren. Meanwhile, decreasing patterns of national STH infections have been monitored by 7 timeso quinquennial national surveys targeting general population. In 1971, the overall intestinal helminth egg positive rate was 84.3% (Ascaris 58.2%, Trichuris 65.4%, and hookworms 10.7%), which became 63.2% in 1976, 41.1% in 1981, 12.9% in 1986, 3.8% in 1992, 2.4% in 1997, and 4.3% (Ascaris 0.03%, Trichuris 0.02%, and hookworms 0%) in 2004. During the control period, national economy rapidly developed, and living standards including environment, sanitation, and agricultural technology greatly improved, which undoubtedly boosted the STH control effects. Our experience indicates that social driving force to establish an eligible national control system to conduct repeated mass chemotherapy, together with improvement of environment and sanitation, is important for initiating and achieving STH control in a developing community.     

Familial aggregation of human susceptibility to co- and multiple helminth infections in a population from the Poyang Lake region, China

Human helminthiases are common in China, especially in rural areas where sanitation conditions are poor. Co- and multiple infections with helminths are strikingly frequent. A cross-sectional parasitological and questionnaire survey was carried out in a population of 3205 individuals belonging to 498 families from five villages in the Poyang Lake region, Jiangxi Province, China, to assess their helminth infection status and to collect information on risk factors for infection. The prevalences for Ascaris lumbricoides, Schistosoma japonicum and Trichuris trichiura were 30.9%, 15.7% and 47%, respectively. Hookworm infection prevalence was low (0.7%). A significant association was observed between A. lumbricoides and T. trichiura infection, and also between S. japonicum and T. trichiura infection. Variance components analysis was undertaken to investigate the aggregation of S. japonicum and the soil-transmitted helminths, A. lumbricoides and T. trichiura. While A. lumbricoides was found to aggregate only at a household level, T. trichiura was shown to cluster predominantly in families. Both genetic and household effects were found to be important in determining the risk of infection with S. japonicum. Variance components analysis for A. lumbricoides/T. trichiura co-infections indicated a significant domestic environmental effect, attributable for 32.7% of the co-infection risk. Aggregation of S. japonicum/T. trichiura co-infection was also observed at a household level. The risk of infection with multiple helminth species, although mainly environmentally influenced, was also shown to have significant involvement of genetic and household components. The results of this study indicate that a shared household is a major contributing risk factor for helminth co-infections and emphasises the need for increased standards of sanitation and hygiene to prevent parasite transmission. Further, the results suggest that susceptibility to one helminth infection is not completely independent of another, and that there exist common genetic factors underlying infection with multiple helminth species.     

V-shaped Pits in Regions of Ancient Baekje Kingdom Paleoparasitologically Confirmed as Likely Human-Waste Reservoirs

In a paleo-parasitological analysis of soil samples obtained from V-shaped pits dating to the ancient Baekje period in Korean history, we discovered Ascaris lumbricoides, Trichuris trichiura, and Clonorchis sinensis eggs. In light of the samples'' seriously contaminated state, the V-shaped pits might have served as toilets, cesspits, or dung heaps. For a long period of time, researchers scouring archaeological sites in Korea have had difficulties locating such structures. In this context then, the present report is unique because similar kind of the ancient ruins must become an ideal resource for successful sampling in our forthcoming paleoparasitological studies.     

High Genetic Variability of Schistosoma haematobium in Mali and Nigeria

Schistosoma haematobium is one of the most prevalent parasitic flatworms, infecting over 112 million people in Africa. However, little is known about the genetic diversity of natural S. haematobium populations from the human host because of the inaccessible location of adult worms in the host. We used 4 microsatellite loci to genotype individually pooled S. haematobium eggs directly from each patient sampled at 4 endemic locations in Africa. We found that the average allele number of individuals from Mali was significantly higher than that from Nigeria. In addition, no significant difference in allelic composition was detected among the populations within Nigeria; however, the allelic composition was significantly different between Mali and Nigeria populations. This study demonstrated a high level of genetic variability of S. haematobium in the populations from Mali and Nigeria, the 2 major African endemic countries, suggesting that geographical population differentiation may occur in the regions.     

Prevalence of Schistosomes and Soil-Transmitted Helminths among Schoolchildren in Lake Victoria Basin,Tanzania

The objectives of this study was to conduct a survey on schistosomiasis and soil-transmitted helminth (STH) infections in order to come up with feasible control strategies in Lake Victoria basin, Tanzania. Depending on the size of the school, 150-200 schoolchildren were recruited for the study. Duplicate Kato-Katz stool smears were prepared from each child and microscopically examined for Schistosoma mansoni and STHs. Urine specimens were examined for Schistosoma haematobium eggs using the filtration technique. After the survey, mass drug administration was done using praziquantel and albendazole for schistosomiasis and STHs infections, respectively. A total of 5,952 schoolchildren from 36 schools were recruited for the study and had their stool and urine specimens examined. Out of 5,952 schoolchildren, 898 (15.1%) were positive for S. mansoni, 754 (12.6%) for hookworms, 188 (3.2%) for Ascaris lumblicoides, and 5 (0.008%) for Trichuris trichiura. Out of 5,826 schoolchildren who provided urine samples, 519 (8.9%) were positive for S. haematobium eggs. The results revealed that intestinal schistosomiasis, urogenital schistosomiasis, and STH infections are highly prevalent throughought the lake basin. The high prevalence of intestinal and urogenital schistosomisiasis in the study area was a function of the distance from Lake Victoria, the former being more prevalent at localities close to the lake, whilst the latter is more so away from it. Control of schistosomiasis and STHs in the study area requires an integrated strategy that involves provision of health education to communities, regular treatments, and provision of adequate safe water supply and sanitation facilities.     

A Cross-Sectional Study on Intestinal Parasitic Infections in Rural Communities,Northeast Thailand

Despite the existence of effective anthelmintics, parasitic infections remain a major public health problem in Southeast Asia, including Thailand. In rural communities, continuing infection is often reinforced by dietary habits that have a strong cultural basis and by poor personal hygiene and sanitation. This study presents a survey of the prevalence of intestinal parasitic infections among the people in rural Thailand. The community-based cross-sectional study was conducted in villages in Khon Kaen Province, northeastern Thailand, from March to August 2013. A total of 253 stool samples from 102 males and 140 females, aged 2-80 years, were prepared using formalin-ethyl acetate concentration methods and examined using light microscopy. Ninety-four individuals (37.2%) were infected with 1 or more parasite species. Presence of parasitic infection was significantly correlated with gender (P=0.001); nearly half of males in this survey (49.0%) were infected. Older people had a higher prevalence than younger members of the population. The most common parasite found was Opisthorchis viverrini (26.9%), followed by Strongyloides stercoralis (9.5%), Taenia spp. (1.6%), echinostomes (0.4%), and hookworms (0.4%). The prevalence of intestinal protozoa was Blastocystis hominis 1.6%, Entamoeba histolytica 0.8%, Entamoeba coli 0.8%, Balantidium coli 0.4%, Iodamoeba bütschlii 0.4%, and Sarcocystis hominis 0.4%. Co-infections of various helminths and protozoa were present in 15.9% of the people. The present results show that the prevalence of parasitic infections in this region is still high. Proactive education about dietary habits, personal hygiene, and sanitation should be provided to the people in this community to reduce the prevalence of intestinal parasite infections. Moreover, development of policies and programs to control parasites is needed.     

Prevalence of Schistosomes and Soil-Transmitted Helminths and Morbidity Associated with Schistosomiasis among Adult Population in Lake Victoria Basin,Tanzania

The objective of this study was to carry out a community survey on schistosomiais and soil-transmitted helminth (STH) infections in order to suggest feasible and effective intervention strategies in Lake Victoria basin, Tanzania. A total of 37 communities selected from 23 districts of the 4 regions in the Lake Victoria basin of Tanzania were involved in the study. From each of the selected locality, 50 adult community members, 25 males and 25 females, were recruited for the study. Each study participant was requested to submit stool and urine specimens. From each stool specimen, duplicate Kato-Katz thick smears were prepared and microscopically examined for Schistosoma mansoni and STH eggs. Urine specimens were processed by the filtration technique and microscopically examined for Schistosoma haematobium eggs. Ultrasound examination for morbidity due to schistosomiasis was performed. Mass treatment was done using praziquantel and albendazole for schistosome and STHs infections, respectively. Out of 1,606 adults who provided stool specimens, 199 (12.4%) were positive for S. mansoni, 349 (21.7%) for hookworms, 133 (8.3%) for Ascaris lumbricoides, and 33 (2.0%) for Trichuris trichiura. Out of 1,400 participants who provided urine specimens, 25 (1.8%) were positive for S. haematobium eggs. Because of the co-endemicity of these afflictions and their impact on vulnerable population groups, the helminthiasis could be simultaneously treated with 2 drugs, praziquantel for schistosomiasis and albendazole for STHs.     

High Prevalence of Haplorchis taichui, Phaneropsolus molenkampi, and Other Helminth Infections among People in Khammouane Province, Lao PDR

The prevalence of liver and intestinal helminth infections, including Opisthorchis, Haplorchis, Phaneropsolus, hookworms, Enterobius, and Taenia, was surveyed in Khammouane province, Lao PDR. Fecal specimens were collected from 1,242 people (590 men and 652 women) in 3 Mekong riverside villages and were examined by the Kato-Katz thick smear technique. The overall helminth egg positive rate was 81.1%. The positive rate for small trematode eggs, including Opisthorchis viverrini, heterophyids, and lecithodendriids, was 81.1% and the positive rate for hookworms was 6.7%. To obtain adult worms, 35 people who were positive for small trematode eggs were treated with 20-30 mg/kg praziquantel and 10-15 mg/kg pyrantel pamoate, and then purged. Diarrheic stools were collected from 33 of these people and searched for helminth parasites using a stereomicroscope. Mixed infections with various helminths (Haplorchis taichui, Haplorchis yokogawai, Prosthodendrium molenkampi, Phaneropsolus bonnei, echinostomes, hookworms, Trichostrongylus spp., Trichuris trichiura, Enterobius vermicularis, and/or Taenia saginata) were found. The total number of helminth specimens collected was 20,907 (approximately 634 per person). The most common species was H. taichui, followed by P. molenkampi, O. viverrini, P. bonnei, E. vermicularis, hookworms, and Trichostrongylus spp. These results show that diverse species of intestinal nematodes, trematodes, and cestodes are infecting humans in Khammouane province, Lao PDR.     

Developing species-specific primers to identify Bulinus truncatus and Bulinus beccari, the intermediate hosts of Schistosoma haematobium in Saudi Arabia

This work aimed to determine the inter- and intra-specific variations in populations of Bulinus truncatus and Bulinus beccari, the intermediate hosts of Schistosoma haematobium in Saudi Arabia, and to develop species-specific primers to identify these snails as a first step in the development of multiplex PCR for simultaneously identifying the snails and diagnosing its infections in a single step. Two populations of B. truncatus were collected from Asser and Bisha (A and B), and two B. beccari populations were collected from Mahial Asser and Merba (C and D). The snails' genomic DNA was extracted and amplified using 5 different primers. The primers displayed variable intra- and inter-specific differences across the populations. The largest RAPD-PCR fragments were cloned into a vector as a preparatory step for sequencing. Similarity searches for the sequenced cloned inserts revealed no similar sequences in the GenBank database or its associated databases. Specific primers used to target the B. truncatus and B. beccari genomes were designed using the Gene Runner program and based on the DNA sequences obtained from RAPD fragment sequence analyses. Using these primers for specific PCRs resulted in expected single-band PCR products of 536 bp for B. beccari and 478 bp for B. truncatus. These results will be helpful for simultaneously identifying B. truncatus and B. beccari snails and diagnosing S. haematobium infections within the snails using single step multiplex PCR.     

Fingerprint of Biomphalaria arabica, the intermediate host of Schistosoma mansoni in Saudi Arabia, using RAPD-PCR

In the time schistosomisis control programs are implemented in many countries, schistosomiasis continues to spread throughout the world. Among these control strategies is the vector control. Within this context, analysis of the genetic variability of the intermediate host snails is important because it allows identification of specific sequences of the genome of this mollusk related to determine their fingerprint. We investigated Biomphalaria arabica, which is found in Saudi Arabia, the intermediate host of Schistosoma mansoni infection. Genetic fingerprint was studied by RAPD-PCR using our own different random primers as well as published primers. The electrophoretic patterns resulting from amplification showed specific polymorphic markers of B. arabica. This information will be helpful in the identification of the snails and demonstrating that RAPD-PCR is an appropriate and efficient methodological approach for establishment of genetic barcode development.     

Schistosoma mansoni: chemoreception through n-acetyl-d-galactosamine-containing receptors in females offers insight into increased severity of schistosomiasis in individuals with blood group A

The role of exposed surface carbohydrates in chemoreception in Schistosoma mansoni females was investigated in vitro. Sexually mature females were treated with peanut (PNA), soybean (SBA) or wheat germ (WGA) agglutinin, and their migration in response to excretory-secretory (ES) products of males was measured in a bioassay system. Random distribution of untreated and lectin-treated females was similar (p=>0.05). PNA-treated females were unresponsive for 1.0 h, after which they exhibited slight repulsion to ES products. SBA-treated females did not respond to ES products for 3.0 h. WGA-treated females were unresponsive for 1.5h, after which they exhibited slight attraction to male ES products. Attempts were made to restore chemoattraction by using specific sugar inhibitors of lectin-binding; chemoattraction was best restored in n-acetyl-d-galactosamine (GalNAc)-treated females. These data suggest that GalNAc-containing receptors, possibly GP50, the major SBA-binding schistosome glycan, mediate chemoreception in schistosome females. These findings may explain the observed differences in morbidity between individuals with different blood groups. Individuals with blood group B or O may afford partial protection because of their natural anti-A or by mounting a more efficient antibody response directed against GalNAc-containing structures shared by blood group A red blood cells.     

Tyrosine kinase and cooperative TGFbeta signaling in the reproductive organs of Schistosoma mansoni

Drug-induced suppression of female schistosome sexual maturation is an auspicious strategy to combat schistosomiasis since the eggs are the causative agent. The establishment of drug targets requires knowledge about the molecular mechanisms that regulate the development of the female reproductive organs, which include vitellarium and ovary. This review summarizes recent studies suggesting tyrosine kinases as important factors for the regulation of female gonad development. In this context, especially cytoplasmatic tyrosine kinases of the Src class seem to play dominant roles. Moreover, experimental data and theoretical concepts are provided supporting a crosstalk between tyrosine kinase and TGFbeta signaling in the production of vitellocytes. Finally, we take advantage from the schistosome genome project to propose a model for the regulation of vitelline-cell production and differentiation.