Distribution of ascariasis, trichuriasis and hookworm infections in Ogun State, Southwestern Nigeria.

BACKGROUND: Ascariasis, Trichuriasis and Hookworm infections poses a considerable public health burden in Sub-Saharan Africa, and a sound understanding of their spatial distribution facilitates to better target control interventions. This study, therefore, assessed the prevalence of the trio, and mapped their spatial distribution in the 20 administrative regions of Ogun State, Nigeria. METHODS: Parasitological surveys were carried out in 1,499 households across 33 spatially selected communities. Fresh stool samples were collected from 1,027 consenting participants and processed using ether concentration method. The locations of the communities were georeferenced using a GPS device while demographic data were obtained using a standardized form. Data were analysed using SPSS software and visualizations and plotting maps were made in ArcGIS software. RESULTS: Findings showed that 19 of the 20 regions were endemic for one or more kind of the three infections, with an aggregated prevalence of 17.2%. Ascariasis was the most frequently observed parasitic infection in 28 communities with a prevalence of 13.6%, followed by hookworm infections with a prevalence of 4.6% while Trichuriasis was the least encountered with a prevalence of 1.7%. The spatial distribution of infections ranges between 5.3-49.2% across the regions. The highest and lowest distribution of overall helminth infections was recorded in Egbado South and Egbado North respectively. Nine regions had infection status between 20.0%-49.2%, while 10 regions had infection status between 5.3%-15.8%. CONCLUSION: This study provides epidemiological data on the prevalence and spatial distribution of ascariasis, trichuriasis and hookworm infections which will add to the baseline data and guide the public health officers in providing appropriate control strategies in the endemic communities.

Prediction of hookworm prevalence in southern India using environmental parameters derived from Landsat 8 remotely sensed data.

Soil-transmitted helminth infections propagate poverty and slow economic growth in low-income countries. As with many other neglected tropical diseases, environmental conditions are important determinants of soil-transmitted helminth transmission. Hence, remotely sensed data are commonly utilised in spatial risk models intended to inform control strategies. In the present study, we build upon the existing modelling approaches by utilising fine spatial resolution Landsat 8 remotely sensed data in combination with topographic variables to predict hookworm prevalence in a hilly tribal area in southern India. Hookworm prevalence data collected from two field surveys were used in a random forest model to investigate the predictive capacity of 15 environmental variables derived from two remotely sensed images acquired during dry and rainy seasons. A variable buffer radius (100-1000 m) was applied to the point-prevalence locations in order to integrate environmental conditions around the village centroids into the modelling approach and understand where transmission is more likely. Elevation and slope were the most important variables in the models, with lower elevation and higher slope correlating with higher transmission risk. A modified normalised difference water index was among other recurring important variables, likely responsible for some seasonal differences in model performance. The 300 m buffer distance produced the best model performance in this setting, with another spike at 700 m, and a marked drop-off in R2 values at 1000 m. In addition to assessing a large number of environmental correlates with hookworm transmission, the study contributes to the development of standardised methods of spatial linkage of continuous environmental data with point-based disease prevalence measures for the purpose of spatially explicit risk profiling.

Comparison of four DNA extraction and three preservation protocols for the molecular detection and quantification of soil-transmitted helminths in stool.

BACKGROUND: A DNA extraction and preservation protocol that yields sufficient and qualitative DNA is pivotal for the success of any nucleic acid amplification test (NAAT), but it still poses a challenge for soil-transmitted helminths (STHs), including Ascaris lumbricoides, Trichuris trichiura and the two hookworms (Necator americanus and Ancylostoma duodenale). In the present study, we assessed the impact of different DNA extraction and preservativation protocols on STH-specific DNA amplification from stool. METHODOLOGY AND PRINCIPAL FINDINGS: In a first experiment, DNA was extracted from 37 stool samples with variable egg counts for T. trichiura and N. americanus applying two commercial kits, both with and without a prior bead beating step. The DNA concentration of T. trichiura and N. americanus was estimated by means of qPCR. The results showed clear differences in DNA concentration across both DNA extraction kits, which varied across both STHs. They also indicated that adding a bead beating step substantially improved DNA recovery, particularly when the FECs were high. In a second experiment, 20 stool samples with variable egg counts for A. lumbricoides, T. trichiura and N. americanus were preserved in either 96% ethanol, 5% potassium dichromate or RNAlater and were stored at 4°C for 65, 245 and 425 days. DNA was extracted using the DNeasy Blood & Tissue kit with a bead beating step. Stool samples preserved in ethanol proved to yield higher DNA concentrations as FEC increased, although stool samples appeared to be stable over time in all preservatives. CONCLUSIONS: The choice of DNA extraction kit significantly affects the outcome of NAATs. Given the clear benefit of bead beating and our validation of ethanol for (long-term) preservation, we recommend that these aspects of the protocol should be adopted by any stool sampling and DNA extraction protocol for downstream NAAT-based detection and quantification of STHs.

Helminth-microbiota cross-talk - A journey through the vertebrate digestive system.

The gastrointestinal (GI) tract of vertebrates is inhabited by a vast array of organisms, i.e., the microbiota and macrobiota. The former is composed largely of commensal microorganisms, which play vital roles in host nutrition and maintenance of energy balance, in addition to supporting the development and function of the vertebrate immune system. By contrast, the macrobiota includes parasitic helminths, which are mostly considered detrimental to host health via a range of pathogenic effects that depend on parasite size, location in the GI tract, burden of infection, metabolic activity, and interactions with the host immune system. Sharing the same environment within the vertebrate host, the GI microbiota and parasitic helminths interact with each other, and the results of such interactions may impact, directly or indirectly, on host health and homeostasis. The complex relationships occurring between parasitic helminths and microbiota have long been neglected; however, recent studies point towards a role for these interactions in the overall pathophysiology of helminth disease, as well as in parasite-mediated suppression of inflammation. Whilst several discrepancies in qualitative and quantitative modifications in gut microbiota composition have been described based on host and helminth species under investigation, we argue that attention should be paid to the systems biology of the gut compartment under consideration, as variations in the abundances of the same population of bacteria inhabiting different niches of the GI tract may result in varying functional consequences for host physiology.

Prevalence and risk factors related to intestinal parasites among children in Department of Rio San Juan, Nicaragua.

BACKGROUND: The present study was carried out to assess the prevalence of intestinal parasite infections among children in Department of Rio San Juan (Nicaragua), to explore the extent of polyparasitism, and to identify the risk factors that might favour transmission of these parasites. METHODS: A coprological study of single stool specimen, collected at random from 382 children (167 boys and 215 girls) aged 2-15 years from two municipalities, and a questionnaire, concerning demographic and epidemiological data on sanitary and behavioural habits, was filled in to identify risk factors. RESULTS: About 93% of the children presented infection. Blastocystis hominis, the most frequently protozoa, and Trichuris trichiura, Ascaris lumbricoides and hookworm, the most prevalent helminths. Polyparasitism (85.4%[326/382]), with the highest percentages detected in females (p=0.001), in the 6-11 year age group (p<0.001) and having a rural background (p<0.001). A firm relationship between any parasite and age (OR=1.2, p=0.036) and rural background (OR=0.3, p=0.027) was detected. Living in rural areas and drinking river water were also positively associated with each of the STH species detected, and walking barefoot was also associated with hookworm infection. CONCLUSIONS: Government efforts should be focused on controlling the risk factors associated with these enteroparasites, with health education programmes in rural areas of Nicaragua.

Intestinal parasites in immigrants in the city of Naples (southern Italy).

The present study was aimed at carrying out a cross-sectional copromicroscopic survey of helminths and intestinal protozoa in immigrants in Naples (southern Italy). Between October 2008 and November 2009, a total of 514 immigrants were tested comparing the FLOTAC dual technique and the ethyl acetate concentration technique. Combined results of the two techniques served as a diagnostic 'gold' standard and revealed an overall prevalence of parasitic infections of 61.9% (318/514). The ethyl acetate concentration technique detected a low number of positive results (49.0%) and this was confirmed for each helminth/protozoa species detected. Among helminths, Trichuris trichiura (3.9%), hookworms (3.7%) and Ascaris lumbricoides (1.4%) were the most prevalent. Strongyloides stercoralis (0.4%), Enterobius vermicularis (0.4%), Schistosoma mansoni (1.0%), Hymenolepis nana (1.6%) and Taenia spp. (0.2%) were also found, as well as zoonotic helminths, as Trichostrongylus spp. (0.8%) and Dicrocoelium dendriticum (0.8%). As regard to pathogenic protozoa, Blastocystis hominis was the most commonly detected (52.7%), followed by Entamoeba histolytica/Entamoeba dispar/Entamoeba moshkovskii (11.9%) and Giardia duodenalis (4.5%). Several issues concerning diagnosis, epidemiology and public health impact of parasitic infections in immigrants are offered for discussion. In conclusion, the present paper pointed out the need of better diagnosis and cure of the immigrant population in order to improve access to health care of this neglected and marginalised population group, for its own protection and care.

Correlation between malaria incidence and prevalence of soil-transmitted helminths in Colombia: an ecologic evaluation.

INTRODUCTION: Recent studies have suggested an association between the soil-transmitted helminth infections and malaria incidence. However, published evidence is still insufficient and diverging. Since 1977, new ecologic studies have not been carried out to explore this association. Ecologic studies could explore this correlation on a population level, assessing its potential importance on public health. OBJECTIVES: The aim of this evaluation is to explore the association between soil-transmitted helminths prevalence and malaria incidence, at an ecologic level in Colombia. MATERIALS AND METHODS: Using data from the National Health Survey, which was carried out in 1980 in Colombia, we calculated Spearman correlation coefficients between the prevalence of: Ascaris lumbricoides, Trichuris trichiura and hookworm, with the 1980 malaria incidence data of the same year provided from the Colombian Malaria National Eradication Service. A robust regression analysis with least trimmed squares was performed. RESULTS: Falciparum malaria incidence and Ascaris lumbricoides prevalence had a low correlation (R²= 0.086) but this correlation was stronger into the clusters of towns with prevalence of Ascaris lumbricoides infection above 30% were only included (R²= 0.916). CONCLUSION: This work showed an ecologic correlation in Colombia between malaria incidence and soil-transmitted helminths prevalence. This could suggest that either there is an association between these two groups of parasites, or could be explained by the presence of common structural determinants for both diseases.

Spatial distribution of soil-transmitted helminths, including Strongyloides stercoralis, among children in Zanzibar.

A programme periodically distributing anthelminthic drugs to school-aged children for the control of soiltransmitted helminthiasis was launched in Zanzibar in the early 1990s. We investigated the spatial distribution of soiltransmitted helminth infections, including Strongyloides stercoralis, in 336 children from six districts in Unguja, Zanzibar, in 2007. One stool sample per child was examined with the Kato-Katz, Koga agar plate and Baermann methods. The point prevalence of the different helminth infections was compared to the geological characteristics of the study sites. The observed prevalences for Trichuris trichiura, Ascaris lumbricoides, hookworm and S. stercoralis were 35.5%, 12.2%, 11.9% and 2.2%, respectively, with considerable spatial heterogeneity. Whilst T. trichiura and hookworm infections were found in all six districts, no A. lumbricoides infections were recorded in the urban setting and only a low prevalence (2.2%) was observed in the South district. S. stercoralis infections were found in four districts with the highest prevalence (4.0%) in the West district. The prevalence of infection with any soil-transmitted helminth was highest in the North A district (69.6%) and lowest in the urban setting (22.4%). A. lumbricoides, hookworm and, with the exception of the North B district, S. stercoralis infections were observed to be more prevalent in the settings north of Zanzibar Town, which are characterized by alluvial clayey soils, moist forest regions and a higher precipitation. After a decade of large-scale administration of anthelminthic drugs, the prevalence of soil-transmitted helminth infections across Unguja is still considerable. Hence, additional measures, such as improving access to adequate sanitation and clean water and continued health education, are warranted to successfully control soil-transmitted helminthiasis in Zanzibar.

Helminth eggs in raw and treated wastewater in the Islamic Republic of Iran.

To assess the type and load of helminths in wastewater and the quality of treatment, we examined the raw and treated wastewater of 8 wastewater treatment plants (WTP) in Tehran and 2 in Isfahan for the presence of helminth eggs during 2002-2003. Wastewater samples obtained from both inlet and effluent of each treatment plant were examined on several occasions using the modified Bailenger method. Untreated entry wastewater in Tehran WTPs contained a larger variety of helminth eggs than those of Isfahan, as well as higher total egg counts. The helminths identified in the influent of Tehran included Ascaris lumbricoides, hookworms, Enterobius vermicularis, Trichostrongylus spp., Taenia spp., Hymenolepis nana and Dicrocoelium dendriticum, while in Isfahan only A. lumbricoides, Trichostriogylus and H. nana were isolated. After treatment, the number of eggs/L fell to < or = 1 egg/L.

Pesquisa de cistos de protozoários, larvas e ovos de helmintos em chupetas / A study on protozoan cysts, helminth eggs larvae in pacifiers

Objetivo: Devido à alta prevalência das enteroparasitoses entre crianças no Brasil e do possível envolvimento de objetos na transmissäo dessas doenças, foi desenvolvido um estudo para pesquisar a presença de cistos de protozoários, larvas e ovos de helmintos em chupetas. Métodos: No período de março a dezembro de 1993, foram examinadas 86 chupetas de crianças na faixa etária de zero a sete anos, residentes no bairro Vila Promessa, município de Alfenas, MG. A pesquisa de cistos, larvas e ovos foi realizada através do exame microscópico do sedimento obtido da centrifugaçäo do líquido resultante da lavagem das chupetas. Os resultados obtidos foram avaliados empregando-se a análise percentual. Paralelamente aos exames, foram realizadas entrevistas com os responsáveis pela criança...

La ultraestructura de leishmania venezuelensis en humanos y gatos naturalmente infectados con leishmaniasis cutánea / The ultrastructure of leishmania venezuelensis in humans and cats naturally infected with cutaneous leishmaniasis

La ultraestructura de la Leishmania venezuelensis en humanos y gatos naturalmente infectados con leishmaniasis cutánea fue similar a la de otras especies conocidas de leishmania que producen enfermedad en humanos. Sin embargo, se observaron algunos hallazgos peculiares, tales como el diámetro promedio, el número y la distancia media entre los microtúbulos peliculares, la presencia de grandes megasomas, el desarrollo de vacuolas fagocíticas gigantes, la dispocisión de los túbulos en el corpúsculo parabasal, la presencia de microtúbulos por debajo de la membrana de la bolsa flagelar y la existencia de una organela excretoria en el polo posterior

Helmintiasis intestinales en niños de una comunidad marginal del municipio Maracaibo. Estado Zulia-Venezuela / Intestinal helminthiasis in children of marginal community of the municipality Maracaibo. State Zulia-venezuela

A fin de analizar el impacto que producen las parasitosis intestinales en la morbilidad infantil se determinó la prevalencia de las helmintiasis intestinales y el tipo de infestación que padece la población infantil de una comunidad marginal del Municipio Maracaibo. Se analizó un espécimen fecal de 151 niños mediante examen al fresco, concentración formol-éter y recuento de huevos por la técnica de Stoll. Se realizó el recuento de vermes expulsados post-tratamiento de Ascaris lumbricoides. Se evidenció prevalecia para Trichuris trichuria, A. lumbricoides, y Ancylostomideos. Se demostró asociación significativa entre helmitiasis y sexo. La intensidad promedio estimada a través del recuento de huevos resultó moderada para T. trichuria y leve para Ancylostomideos. En las manifestaciones por A. lumbricoides la intensidad promedio resultó severa según recuento de huevos, y moderada al calcularse por vermes expulsados post-tratamiento. T. trichuria, A. lumbricoides y los Ancylostomideos alcanzaron las mayores frecuencias. Se encontró discrepancia en los resultados para la especie A. lumbricoides donde el recuento de huevos mostró infestaciones moderadas

Manifestaciones clinicas y laboratoriales de la uncinariasis / Clinical and laboratory and manifestations of uncinariasis

Los realizaron un esturdio de las principales manifestaciones clinicas y laboratoriales que acompanan la infestacion por uncinarias en 62 ninos lactantes en un periodo de 2 anos y que ingresaron a la Sala Primera del Hospital de Ninos "Dr. Mario Ortiz Suarez" con el diagnostico principal de esta parasitosis. Como manifestacion principal recalcamos la anemia con todo su cortejo sintomatologico de palidez, sudoracion, anorexia, astenia, disnea y choque hipovolemico. Ademas tenemos la desnutricion que acompana casi siempre al cuadro clinico; la diarrea en sus dos formas; aguda o cronica y finalmente los sintomas referentes al sangrado intestinal activo: melena y enterorragia. Todos nuestros pacientes presentaron anemia, algunos de menor grado; pero la mayoria fueron anemias severas, con hemoglobinas por debajo de 7 g/dL y aun hasta por debajo de 2g/dL.

Repercusiones sociales y económicas de las helmintiasis transmitidas por el suelo / Social and economic repercussion of soil-transmitted helminthiases

Se analizan brevemente algunos aspectos relacionados con las pérdidas socio-económicas por uncinariasis y ascariasis que ocurrieron en Japón, cuando estas parasitosis tenían prevalencia muy alta. El autor también hace referencia a una fórmula para determinar la eficiencia de las medidas aplicadas para el control de las helmintiasis transmitidas por el suelo

Diagnóstico parasitológico y evaluación hematológica en pacientes parasitados por uncinarias / Parasitologic diagnosis and hematologic evaluation in patients parasited by uncinary

Se examinaron 445 muestras de heces de pacientes referidos de distintos centros de salud de Ciudad Bolívar al laboratorio de Parasitología de la Escuela de Medicina UDO-Bolivar realizándose exámen directo de heces y técnica de Willis "flotación en salmuera" presentándose en ambos casos la positividad a una u otra parasitosis; se comparó el porcentaje de casos positivos a Uncinarias por los 2 métodos y se hizo valoración hematológica de los mismos; además de relacionar los casos de infección por Uncinarias con el sexo y edad de los pacientes, se concluyó que el método de Willis fué muy superior al método directo encontrándose positividad a Uncinarias en un 85,71%, por el método directo se encontró positividad en un 14,28%. La parasitosis más frecuentemente encontrada por el método directo fue la Tricocefaliasis. La patología predomino en el grupo etario comprendido entre 7,14 años (43,33%) seguido del grupo etario de 2 a 6 años (30%)