Complex interactions in soil-transmitted helminth co-infections from a cross-sectional study in Sri Lanka.

Background: Co-infection with multiple soil-transmitted helminth (STH) species is common in communities with a high STH prevalence. The life histories of STH species share important characteristics, particularly in the gut, and there is the potential for interaction, but evidence on whether interactions may be facilitating or antagonistic are limited. Methods: Data from a pretreatment cross-sectional survey of STH egg deposition in a tea plantation community in Sri Lanka were analysed to evaluate patterns of co-infection and changes in egg deposition. Results: There were positive associations between Trichuris trichiura (whipworm) and both Necator americanus (hookworm) and Ascaris lumbricoides (roundworm), but N. americanus and Ascaris were not associated. N. americanus and Ascaris infections had lower egg depositions when they were in single infections than when they were co-infecting. There was no clear evidence of a similar effect of co-infection in Trichuris egg deposition. Conclusions: Associations in prevalence and egg deposition in STH species may vary, possibly indicating that effects of co-infection are species dependent. We suggest that between-species interactions that differ by species could explain these results, but further research in different populations is needed to support this theory.

Soil Contamination Rate, Prevalence, Intensity of Infection of Geohelminths and Associated Risk Factors among Residents in Bazou (West Cameroon).

BACKGROUND: Soil-transmitted helminths (STH) infections remain an important public health problem in the tropics. This study aimed to evaluate the soil contamination rate and prevalence of infestations of geohelminth among residents in Bazou. METHODS: Four hundred (400) soil samples and 182 stool specimens were collected respectively from four sites and from inhabitants aged 1 to 40 years and above in 12 households. A questionnaire was administered to evaluate risk factors of STH-infections. Soil samples were screened using sucrose centrifugal flotation method while stool specimens were analyzed using two techniques. RESULTS: Out of the 400 soil and 182 stool samples examined, 13(3.3%) and 9(4.95%) were positive respectively after analyses. Soil contamination rates were 2%, 1% and 0.3% for Ascaris, Trichuris and hookworm eggs respectively while 4.95% of stool samples were positive to one species nematode (Ascaris lumbricoides). The soil contamination rate observed (5%) in the rainy season was significantly different (p>0.05) from the one observed (1.5%) in the dry season. Irrespectively of the season, the most frequent parasite identified was Ascaris spp. Soils around houses were more contaminated 6(12%) as compared to those collected from markets 5(10%) and roads 2(4%) while those around classrooms were not contaminated. Participants in the age group of 1-10 were more infected. Factors such as no hand washing habit and untrimmed finger nails were found to be important risk factors for STH. CONCLUSION: These results suggest the necessity to promote measures that could help to reduce STH infections.

Ancient Soil-Transmitted Parasite Eggs Detected from the Sixth Century Three Kingdom Period Silla Tomb.

The parasitic infection patterns of the Joseon period have begun to be revealed in a series of paleoparasitological studies. However, parasitism prevailing during or before the Three Kingdom period is still relatively unexplored. In the present study, we therefore conducted parasitological examinations of soil and organic-material sediments precipitated upon human hipbone and sacrum discovered inside an ancient Mokgwakmyo tomb dating to the Silla Dynasty (57 BCE-660 CE). Within the samples, we discovered ancient Ascaris lumbricoides (eggs per gram [EPG], 46.6-48.3) and Trichuris trichiura (EPG, 32.8-62.1) eggs, the species commonly detected among Korean populations until just prior to the 1970s. These findings show that soil-transmitted parasitic infection among the Silla nobility might not have been uncommon. This is the first-ever report on the presence of ancient parasite eggs in the samples obtained from a Three Kingdom period tomb; and it also presents the earliest positive results for any of the ancient South Korean tombs paleoparasitologically examined to date.

Early developmental stages of Ascaris lumbricoides featured by high-resolution mass spectrometry.

Ascaris lumbricoides is responsible for a highly disseminated helminth parasitic disease, ascariosis, a relevant parasitosis that responds for great financial burden on the public health system of developing countries. In this work, metabolic fingerprinting using high-resolution mass spectrometry (HRMS) was employed to identify marker molecules from A. lumbricoides in different development stages. We have identified nine biomarkers, such as pheromones and steroidal prohormones in early stages, among other molecules in late development stages, making up four molecules for fertilized eggs, four marker molecules for first larvae (L1) and one marker molecule for third larvae (L3). Therefore, our findings indicate that this approach is suitable for biochemical characterization of A. lumbricoides development stages. Moreover, the straightforward analytical method employed, with almost no sample preparation from a complex matrix (feces) using high-resolution mass spectrometry, suggests that it is possible to seek for an easier and faster way to study animal molding processes.

Quality control in the diagnosis of Trichuris trichiura and Ascaris lumbricoides using the Kato-Katz technique: experience from three randomised controlled trials.

BACKGROUND: An accurate diagnosis of soil-transmitted helminthiasis is important for individual patient management, for drug efficacy evaluation and for monitoring control programmes. The Kato-Katz technique is the most widely used method detecting soil-transmitted helminth eggs in faecal samples. However, detailed analyses of quality control, including false-positive and faecal egg count (FEC) estimates, have received little attention. METHODS: Over a 3-year period, within the frame of a series of randomised controlled trials conducted in Pemba, United Republic of Tanzania, 10% of randomly selected Kato-Katz thick smears were re-read for Trichuris trichiura and Ascaris lumbricoides eggs. In case of discordant result (i.e. positive versus negative) the slides were re-examined a third time. A result was assumed to be false-positive or false-negative if the result from the initial reading did not agree with the quality control as well as the third reading. We also evaluated the general agreement in FECs between the first and second reading, according to internal and World Health Organization (WHO) guidelines. RESULTS: From the 1,445 Kato-Katz thick smears subjected to quality control, 1,181 (81.7%) were positive for T. trichiura and 290 (20.1%) were positive for A. lumbricoides. During quality control, very low rates of false-positive results were observed; 0.35% (n = 5) for T. trichiura and 0.28% (n = 4) for A. lumbricoides. False-negative readings of Kato-Katz thick smears were obtained in 28 (1.94%) and 6 (0.42%) instances for T. trichiura and A. lumbricoides, respectively. A high frequency of discordant results in FECs was observed (i.e. 10.0-23.9% for T. trichiura, and 9.0-11.4% for A. lumbricoides). CONCLUSIONS: Our analyses show that the rate of false-positive diagnoses of soil-transmitted helminths is low. As the probability of false-positive results increases after examination of multiple stool samples from a single individual, the potential influence of false-positive results on epidemiological studies and anthelminthic drug efficacy studies should be determined. Existing WHO guidelines for quality control might be overambitious and might have to be revised, specifically with regard to handling disagreements in FECs.

Application of the Fenton process in the elimination of helminth eggs.

This study relates to a method for evaluating the degradation efficiency of Ascaris lumbricoides eggs through a Fenton reaction, using hydrogen peroxide (H2O2) at 100, 250, and 500 mg/L, ferrous sulfate (FeSO4) at 458 mg/L Fe(2+) and pH values of 3, 4.5, and 6. The experiments were conducted according to a 3(2) experimental design, with 1:1, 3:1, and 5:1 (H2O2/Fe(2+)) molar ratios. The oxidation and flocculation stages were performed at 130 rpm during 2 hours and at 25-30 rpm during 20 min, respectively. As a result of the Fenton reaction, an average of 91.2% Ascaris lumbricoides egg degradation was achieved at pH 6 using a 500 mg/L dose of H2O2 and a 3:1 (H2O2/Fe(2+)) molar ratio. Thus, this process is an alternative for eliminating parasites that are resistant to conventional disinfection processes and significantly reduces the human health hazard they represent.

Biorheological action of Ascaris lumbricoides larvae on human erythrocytes.

Previous studies have shown that A. lumbricoides extracts capture sialic acid (SA) from human red blood cells (RBC). The aim of this work was to study hemorheological alterations in vitro caused by parasite larvae. The biorheological action of three larva concentrates of first and second larval stage on group O erythrocytes was analyzed by incubating the erythrocyte packed together with an equal volume of larvae (treated RBC) and PBS (control RBC). Distribution and parameters of aggregation (digital image analysis), aggregation kinetics (erythroaggregameter), and viscoelasticity (erythrodeformeter) were measured. The digital image analysis showed that all the larvae diminished the isolated cells percentage and increased the size of the formed aggregates. The aggregate formation velocity was lower in the treated than in the control. The deformability index (ID) values of treated RBC did not present variations with respect to those of the control, but a decrease in the erythrocyte elastic modulus (µ(m)) and membrane surface viscosity (η(m)) values was observed, indicating that the larvae not only induced a diminution in the membrane surface viscosity of RBC but also altered the dynamic viscoelasticity of the membrane. Experiments carried out in vitro support the conclusion that the contact between larvae and RBC produces hemorheological alterations.

Disinfection of domestic effluents by gamma radiation: effects on the inactivation of Ascaris lumbricoides eggs.

This work investigated the inactivation of Ascaris lumbricoides eggs in domestic effluents by gamma radiation from a (60)Co source. Domestic wastewater was treated in a compact demo-scale system consisting of a UASB reactor and a trickling filter; treatment was carried out at the Center for Research and Training on Sanitation (CePTS), Federal University of Minas Gerais, in Belo Horizonte-MG, Brazil. One-liter of treated wastewater samples was artificially contaminated with an average of 1000 non-embryonated Ascaris lumbricoides eggs from human feces; samples were then irradiated in a multiple-purpose irradiator at different doses (0.5-5 kGy). Eggs were recovered from the wastewater and the viability of these irradiated eggs was evaluated; the description of the egg developmental phases with each dose of gamma radiation was recorded. Radiation doses of 3.5 kGy effectively disinfected effluents with lower concentrations of A. lumbricoides eggs; higher radiation doses of 5 kGy were necessary to disinfect effluents with higher eggs concentrations.

Captación de ácido siálico por larvas de Ascaris lumbricoides durante incubación in vivo / Sialic acid capture by Ascaris lumbricoides larvae during in vivo incubation / Captação de ácido siálico por vermes de Ascaris lumbricoides durante incubação in vivo

La agregación eritrocitaria afecta la microcirculación y su estudio es importante en las vasculopatías. Se comunicó que Ascaris lumbricoides puede capturar ácido siálico (AS) del eritrocito y alterar la carga aniónica del glóbulo. El objetivo de este trabajo fue estudiar la captación de AS por larvas de A. lumbricoides incubadas in vivo con eritrocitos. Se trabajó con un concentrado de larvas ([CLAL]) incubado en 4 tubos con buffer fosfato y antibióticos. En dos se agregaron eritrocitos Grupo O. Los restantes fueron controles. Se incubaron a 37 °C (5% CO2) durante 24 y 48 horas. Las larvas fueron separadas, recolectadas, concentradas y contadas microscópicamente (larvas/mL: [CLAL]1: 1500-1700; [CLAL]3 1600-1800; [CLAL]2 y 4: 200400). Se utilizaron las técnicas de Inhibición de la Agregación por Polibrene (IAP) y Alcian Blue (AB). La IAP mostró una diferencia significativa entre los Títulos de Polibrene diluido en solución fisiológica y en [CLAL]1 y 2 que fueron incubados con eritrocitos 24 y 48 horas respectivamente. No hubo variación en el Título de los Controles correspondientes ([CLAL]3 y [CLAL]4). AB realizada en [CLAL]1 y [CLAL]3, determinó CASCap%= 6,65% ± 0,36 y CAS[CLAL]3% = 0,67% ± 0,36. La experiencia demostró la captación de AS por las larvas incubadas in vivo con eritrocitos y sugirió que ellas no presentan AS intrínseco. El secuestro de AS durante la migración larvaria podría ser importante en la interacción parásito-hospedador.

Erythrocyte aggregation affects microcirculation and its study is important in vascular diseases. It was communicated that Ascaris lumbricoides can capture erythrocyte sialic acid (SA) and alter the anionic charge on the red cell. The aim of this work was to study SA capture by A. lumbricoides larvae incubated in vivo with erythrocytes. Work was performed with concentrated larvae ([ALLC]) incubated in 4 tubes with phosphate buffer and antibiotics. Group O erythrocytes were added in two Tubes. The remaining were Controls. They were incubated at 37 °C (5% CO2) for 24 and 28 hours. The larvae were separated, collected, concentrated and counted microscopically (larvae/mL: [ALLC]1:1500-1700; [ALLC]3: 1600-1800; [ALLC]2 and 4: 200- 400). Aggregation Inhibition by Polybrene (AIP) and Blue Alcian (BA) techniques were used. AIP showed a significant difference between Polybrene Titers diluted with physiological solution and with [ALLC]1 and 2, which were incubated with erythrocytes 24 and 48 hours respectively. There was no change in the Title of the corresponding Controls. BA performed in [ALLC]1 and [ALLC]3 determined CapSAC = 6.65% ± 0.36 and SAC[CLAL]3 %= 0.67% ± 0.36. The experience showed SA capture by larvae incubated in vivo with erythrocytes and it suggested that they have no intrinsic SA. SA kidnapping during the larval migration could be important in parasite-host interaction.

A agregação eritrocitária afeta a microcirculação e seu estudo é Importante nas vasculopatias. Foi comunicado que o Ascaris lumbricoides pode capturar ácido siálico (AS) do eritrocito e alterar a carga aniônica do glóbulo. O objetivo deste trabalho foi estudar a captação de AS por vermes de A. lumbricoides incubados in vivo com eritrocitos. Trabalhouse com uma concentração de larvas ([CLAL]) incubada em 4 tubos com buffer fosfato e antibióticos. Em dois foram agregados eritrocitos Grupo O. Os restantes foram controles. Foram incubados a 37 °C (5% CO2) durante 24 e 48 horas. As larvas foram separadas, coletadas, concentradas e contadas microscopicamente (larvas/mL: [CLAL]1: 1500-1700; [CLAL]3 1600-1800; [CLAL]2 e 4: 200-400). As técnicas utilizadas foram de Inibição da Agregação por Polybrene (IAP) e Alcian Blue (AB). A IAP mostrou uma diferenga significativa entre os Títulos de Polybrene diluido em solução fisiológica e em [CLAL]1 e 2 que foram incubados com eritrocitos 24 e 48 horas respectivamente. Näo houve variação no Título dos Controles correspondentes ([CLAL]3 e [CLAL]4). AB realizada em [CLAL]1 e [CLAL]3, determinou CASCap%= 6,65% ± 0,36 e CAS[CLAL]3% = 0,67% ± 0,36. A experiencia demons-trou a captação de AS pelos vermes incubados in vivo com eritrócitos e sugeriu que eles näo apresentam AS intrínseco. O sequestro de AS durante a migração de larvas poderia ser importante na interação parasita-hospedeiro.

Soil transmitted helminths and schistosoma mansoni infections among school children in Zarima town, northwest Ethiopia.

BACKGROUND: In Ethiopia, because of low quality drinking water supply and latrine coverage, helminths infections are the second most predominant causes of outpatient morbidity. Indeed, there is a scarcity of information on the prevalence of soil transmitted helminths and Schistosomiasis in Ethiopia, special in study area. Therefore, the aim of this study was to determine the prevalence and associated risk factors of soil transmitted helminths and intestinal Schistosomiasis. METHODS: Cross-sectional study was conducted among 319 school children of Zarima town from April 1 to May 25, 2009. A pre-tested structured questionnaire was used to collect socio-demographic data and possible risk factors exposure. Early morning stool samples were collected and a Kato Katz semi concentration technique was used to examine and count parasitic load by compound light microscope. Data entry and analysis was done using SPSS-15 version and p-value < 0.05 considered statistically significant. RESULTS: Out of 319 study subjects, 263 (82.4%) of the study participants infected with one or more parasites. From soil transmitted helminths, Ascaris lumbricoides was the predominant isolate (22%) followed by Hookworms (19%) and Trichuris trichiura (2.5%). Schistosoma mansoni was also isolated in 37.9% of the study participants. Hookworm and S. mansoni infections showed statistically significant associations with shoe wearing and swimming habit of school children, respectively. CONCLUSION: Prevalence of soil transmitted helminths (STH) and S.mansoni was high and the diseases were still major health problem in the study area which alerts public health intervention as soon as possible.

Efecto producido por Ascaris lumbricoides sobre la carga superficial eritrocitaria utilizando el Método de Polibrene / Effect of Ascaris lumbricoides on the erythrocyte superficial charge using Polybrene Method

Los ácidos siálicos (AS) contenidos en glucoproteínas y glucolípidos participan en diversas funciones biológicas y su presencia en el eritrocito tiene importancia hemorreológica y hemodinámica. Se considera que los AS intervendrían en la interacción parásito-hospedador. El objetivo de este trabajo fue estudiar el efecto producido por A. lumbricoides sobre la carga superficial eritrocitaria utilizando el Método de Polibrene. Se trabajó con 51 extractos de parásito adulto ([EA]) y con 4 concentrados larvales ([CLAL]: 2000/ 1000/ 500/ 250 larvas/ mL). El método fue aplicado en eritrocitos no tratados (Control) y tratados con [EA]/ los 4 [CLAL] de forma simultánea. El tratamiento con las larvas se realizó en 18 experiencias. Los eritrocitos tratados con el 37, 25% de los [EA] presentaron menor agregación en relación al Control. Los análisis estadísticos mostraron que este efecto no se relacionó con la concentración proteica del [EA]. La disminución de agregado en el tratamiento con [CLAL] fue dependiente de la concentración larvaria y se relacionó a concentraciones = a 500 larvas/ mL. Se observó que la fijación [EA]/ [CLAL] al eritrocito no era fuerte. Los resultados demostraron que A. lumbricoides secuestra AS eritrocitario. Esta captación podría influir en la patología y / o participar en la evasión de la respuesta inmune del hospedador.

Sialic acids (SA) contained in glycoproteins and glycolipids participate in various biological functions; besides, its presence on the erythrocyte surface has both hemodynamical and hemorheological importance. SA are thought to intervene in the parasite-host interaction. The aim of this work was to study the effect of Ascaris lumbricoides on the erythrocyte superficial charge by using Polybrene Method. Work was carried out on 51 adult parasite extracts ([AE]) and 4 (larvae) larvae concentrates ([ALLC]: 2000 / 1000 / 500 / 250 larvae/ mL). The method was applied to non-treated (Control) and treated red cells with [AE] / all 4 [ALLC] simultaneously. Larvae´ treatment was conducted over 18 experiences. Erythrocytes treated with 37. 25% of the [AE] had lower aggregation than the Control. The statistical analysis showed that this effect was not related to the protein concentration of [AE]. The aggregate decrease in the treatment with [ALLC] was dependent on larvae concentration and it was related to larvae concentrations = 500 larvae/ mL. It was observed that the [AE]/ [ALLC] fixation to the erythrocyte was not strong. The results have shown that A. lumbricoides sequestrates SA erythrocyte. This capture could affect the pathology and/or participate in the escape of the host's immune response.

Trickle or clumped infection process? An analysis of aggregation in the weights of the parasitic roundworm of humans, Ascaris lumbricoides.

Studying the distribution of parasitic helminth body size across a population of definitive hosts can advance our understanding of parasite population biology. Body size is typically correlated with egg production. Consequently, inequalities in body size have been frequently measured to infer variation in reproductive success (VRS). Body size is also related to parasite age (time since entering the definitive host) and potentially provides valuable information on the mode of acquisition and establishment of immature (larval) parasites within the host: whether parasites tend to establish singly or in aggregates. The mode of acquisition of soil-transmitted helminths has been a theoretical consideration in the parasitological literature but has eluded data-driven investigation. In this paper, we analyse individual Ascaris lumbricoides weight data collected from a cohort of human hosts before and after re-infection following curative treatment, and explore its distribution within and among individuals in the population. Lorenz curves and Gini coefficients indicate that levels of weight inequality (a proxy for VRS) in A.lumbricoides are lower than other published estimates from animal-helminth systems. We explore levels of intra-host weight aggregation using statistical models to estimate the intraclass correlation coefficient (ICC) while adjusting for covariates using a flexible fractional polynomial transformation approach capable of handling non-linear functional relationships. The estimated ICCs indicate that weights are aggregated within hosts both at equilibrium and after re-infection, suggesting that parasites may establish within the host in clumps. The implications of a clumped infection process are discussed in terms of ascariasis transmission dynamics, control and anthelmintic resistance.

[Larval stages of Ascaris lumbricoides: hyaluronan-binding capacity]. / Estados larvales de Ascaris lumbricoides: capacidad de unión a acido hialurónico.

Hyaluronic acid has important functions in inflammatory and tissue reparation processes. Owing to the varied strategies of the parasites to evade the host's immune response, as well as the multiple functions and physiological importance of hyaluronic acid, the aim was to study the hyaluronan binding capacity by Ascaris lumbricoides larval stages. Larval concentrates were prepared by hatching A. lumbricoides eggs. The larvae were collected by the Baermann method. The test of serum soluble CD44 detection by Agregation Inhibition was modified. All the larval concentrates presented hyaluronan binding capacity. The obtained results allow to suppose the existence of an hyaluronic acid specific receptor in A. lumbricoides. This receptor eventually might compete with the usual receptors of the host. The parasite might use this mechanism to evade the immune response.

The relative influence of polyparasitism, environment, and host factors on schistosome infection.

Where prevalence of geohelminths and schistosomes is high, co-infections with multiple parasite species are common. Previous studies have shown that the presence of geohelminths either promotes or is a marker for greater prevalence and intensity of Schistosoma mansoni infections. Some of this apparent synergy may simply represent shared conditions for exposure, such as poor sanitation, and may not suggest a direct biologic interaction. We explored this question in a study of 13,279 school children in Jequié, Bahia, Brazil, with a survey of demographic characteristics and stool examinations. Cross-sectional analysis revealed a statistically significant increase in the prevalence and intensity of S. mansoni infection with increasing numbers of geohelminth species (OR 2.5, 95% CI 1.38-3.64). Less than 20% of the strength of this association was contributed by socioeconomic status or environmental conditions. Thus, polyparasitism itself, as well as intrinsic host factors, appears to produce greater susceptibility to additional helminth infections.

Immunity, immunoregulation and the ecology of trichuriasis and ascariasis.

Immune responses to human roundworm (Ascaris lumbricoides) and whipworm (Trichuris trichiura) and their role in controlling worm populations are reviewed. Recent immunoepidemiological data implicate T(H)2-mediated responses in limiting A. lumbricoides and T. trichiura populations. Reinfection studies further suggest that IL-5 cytokine responses are negatively associated with adult recruitment in T. trichiura but not A. lumbricoides and may therefore be involved in negative intraspecific and interspecific interactions mediated through the host immune system. The importance of inducible immunoregulatory networks in the ecology of the host-parasite relationship is considered, with particular regard to possible manipulative strategies by the parasites. This aspect of the worms' interaction with the host immune system is both poorly known and potentially central to an understanding of parasite population dynamics and the evolutionary pressures that have shaped present-day host-parasite associations. Some possible implications of worm-mediated immunomodulation for the occurrence of bystander infectious diseases in human populations and the management of de-worming programmes are also discussed.

[Effects of detergents and disinfectants on the development of Ascaris lumbricoides eggs]. / Atividade de detergentes e desinfetantes sobre a evolução dos ovos de Ascaris lumbricoides.

Ascaris lumbricoides infection is acquired via ingestion of embryonated eggs of the parasite, thus justifying the search for ovicidal compounds. We studied the effect of 16 household and laboratory detergents and disinfectants on the embryogenesis of this helminth. Children carrying this infection were treated with levamisole. Eliminated female worms were collected and dissected to obtain eggs from the uteri. The eggs were placed in contact with various products at different dilutions and for various periods of time. After washing, eggs were incubated at 28 grades C for 20 days, for viability tests and to determine the embryonation rate. Only one product completely inhibited the embryonation of eggs at every dilution and for every time period tested. Five products inhibited more than 50% of embryonation, while six inhibited less than 50%. Three products showed no effect on embryonation, while for one the percentage of embryonated eggs was higher than in the control tubes.

Anthelminthic efficacy of traditional herbs on Ascaris lumbricoides.

The ascaricidal efficacy of six commonly used traditional herbs. Artemesia santonica, Inula helenium, Cassia abutnsifolla, Albizzia lebbek, Acacia auriculoformis and oil of Apium graveolens, was tested in vitro against the eggs and larvae of Ascaris lumbricoides. Aqueous extracts of 1% Artemesia and 5% of Albizzia and Inula were effective in killing both the infective larvae ill less than 40 days and eggs in 20 days. The results showed that Artemesia, Albizzia and to less extent Inula were promising antihelmintics against Ascaris lumbricoides. Extracts of the other tested herbs were less or no value.