Human infections by the rat tapeworm Hymenolepis diminuta in China.

The rat tapeworm Hymenolepis diminuta is a parasite that usually uses rats as a definitive host. It also infects humans and non-human primates. Human infections have been reported in 80 countries worldwide, including China. Nevertheless, nearly all the literature on human infections in China by the rat tapeworm is in Chinese journals, which are very difficult to access by readers outside China. The main aim of the current manuscript was to systematically review human infections by the rat tapeworm in China for readers inside and outside the country. Chinese characters for H. diminuta were used to search several databases, including Google Scholar. In total, 511 infections were reported in 24 Chinese provinces/autonomous regions, which surpassed 320 in Costa Rica as the country with the highest number of infections. Furthermore, three nationwide surveys on parasitic infections in the past 3 decades revealed detailed prevalence of this parasite along with that of roundworm, whipworm, hookworm and pinworm in Chinese populations. These data contribute to better understanding of this greatly neglected zoonosis in the world's most populated country.

Hymenolepiasis Caused by Hymenolepis nana in Humans and Natural Infection in Rodents in a Marginal Urban Sector of Guayaquil, Ecuador.

BACKGROUND Hymenolepiasis is a globally prevalent zoonosis of the monoxenic cycle. Humans acquire the disease through fecal-oral transmission by ingesting food or water with infective eggs from infected rodents. This report presents 3 cases of hymenolepiasis in children, due to zoonotic transmission from rodents and presumably associated with the consumption of powdered milk contaminated with infective eggs of Hymenolepis nana, and shows that awareness and early diagnosis contributed to timely treatment of the disease. CASE REPORT Three children, aged 9, 12, and 13 years, living in a marginal urban area of Guayaquil, Guayas province, Ecuador, presented symptoms of diarrhea, low body weight, abdominal discomfort, anorexia, paleness, and anal itching. Subsequently, their fecal samples were analyzed by direct coproparasitic methods, flotation and sedimentation with centrifugation using saline solution; the presence of H. nana eggs was determined. Blood biometry was performed. Further, 10 rodents were captured and necropsied to obtain intestinal contents. The powdered milk consumed by the children was analyzed, the same powder that contained rodent feces. Subsequently, these were studied with the above-mentioned coproparasitic methods. H. nana eggs were identified in the 6 trapped rodents, the powdered milk, and the feces of rodents found in the milk powder. CONCLUSIONS Hymenolepiasis can affect populations of endemic areas. In this case, the disease was identified in 3 children, who were diagnosed with eosinophilia and anemia. Additionally, the presence of H. nana eggs in captured rodents and in powdered milk was determined, indicating that the community was exposed to this zoonotic disease.

Hymenolepis diminuta, phylogenetic analyses of nuclear rRNA + ITS and mitochondrial cox1 and its infections in non-human primates.

Hymenolepis diminuta is a tapeworm commonly found worldwide in small rodents such as rats with occasional reports in other definitive hosts such as primates including chimpanzees and humans. It has not been reported in African green monkey (AGM, Chlorocebus sabaeus), and the parasite's molecular phenotype and phylogeny remain primitively sketchy. The aims of the current study were to determine if H. diminuta infected AGMs, to molecularly characterize H. diminuta and to review its infection in non-human primates. Feces of AGMs were examined visually for adult helminths and microscopically for eggs using centrifugation flotation. Total DNA extracted from eggs was amplified by PCR followed by DNA sequencing of targeted sequences of nuclear rRNA + internal transcribed spacers (ITS) and mitochondrial cox1. Phylogenetic analyses were performed. The DNA sequences of both nuclear rRNA + ITS and mitochondrial cox1 showed more than 98% and 99% identity to the known sequences respectively. Hymenolepis diminuta has been reported in various non-human primates with the highest prevalence of 38.5% in the white-headed capuchin monkey. The study presented here confirms that this tapeworm is capable of infecting various species of non-human primates with the first report of infections in AGM. Phylogenetic analyses of rRNA + ITS and mitochondrial cox1 demonstrated three separated clades I, II and III with the newly described AGM1 isolate belonging to the clade I. Whether these differences are at species level remains to be confirmed.

Worldwide overview of human infections with Hymenolepis diminuta.

Hymenolepis diminuta is a zoonotic cestode parasitizing the small intestine of rodents (definitive hosts). Humans can accidentally enter into the life cycle of this tapeworm via the ingestion of infected insects (intermediate hosts) containing cestode cysticercoids in their body cavity. More than two centuries after the first record in humans, there are no accurate estimates of the number of human cases around the world. In order to have a more precise idea about the number of human cases with H. diminuta and the current status of the disease (hymenolepiasis) worldwide, we conducted a literature review of published records on human infection with H. diminuta. One thousand five hundred and sixty-one published records of infection with H. diminuta from 80 countries were identified. This review presents an estimate of the number of human cases with H. diminuta and a current overview of the prevalence, geographic distribution, symptoms, diagnosis, exposure to infective stages, and therapeutic approaches for this underestimated zoonotic tapeworm.

Morphological and molecular identification of hymenolepidid cestodes in children and synanthropic rodents from rural Mexico.

Hymenolepidid cestodes of synanthropic rodents represent a risk for public health. In order to describe the occurrence of hymenolepidids in children and the role of rodents as a potential source of infection, we conducted a morphological and molecular survey on cestodes in two rural villages from Yucatan, Mexico. One hundred and thirty-five stool samples from children (64 from Paraíso and 71 from Xkalakdzonot), 233 Mus musculus (159 from Paraíso and 74 from Xkalakdzonot) and 125 Rattus rattus (7 from Paraíso and 118 from Xkalakdzonot) were analyzed for the presence of cestodes. Three hymenolepidid species were identified morphologically: Hymenolepis nana in 7.8% of children from Paraíso, Hymenolepis microstoma in 4.4% of M. musculus from Paraíso and Hymenolepis diminuta in 15.3% of R. rattus from Xkalakdzonot. The molecular characterization and phylogenetic analysis based on mitochondrial cytochrome c subunit 1 (CO1) gene and ribosomal internal transcribed spacer 1 (ITS1) region, confirmed the identity of the three cestodes isolated from Yucatan. Phylogeny of the CO1 gene identified intraspecific genetic differences within H. nana ranging from 0 to 5%, in H. microstoma from 0 to 0.4%, and in H. diminuta ranged from 0 to 6.5% which suggests, the presence of complex species within H. nana and H. diminuta infecting humans and rodents, as reported by other authors. Based on the morphological and molecular results, and the epidemiological evidence, infections with H. nana suggest a non-zoonotic transmission; however, the presence of H. microstoma and H. diminuta in synanthropic rodents serve as a possible source for human infection.

Elimination of morbidity due to soil-transmitted helminthiases among Afghan schoolchildren.

Large sectors of the Afghan population have limited access to safe water and sanitation, which increases the risk of transmission of water- and food- borne diseases, including Soil-Transmitted Helminth (STH) infections. STHs interfere with the human host's health status, and their burden of disease is highest among children of school age. Based on the results of a nationwide survey conducted in 2003, which showed an STH prevalence of 47.2%, and with the aim of reducing morbidity among school children, Afghanistan has been conducting nationwide deworming for preschool-age and school-age children since 2004. In 2017, 14 years after the first baseline assessment, a follow-up survey was carried out among schoolchildren aged 8-10 years to provide an update on STH epidemiology and facilitate evidence-informed planning of future deworming campaigns. Stool samples were collected from 2263 pupils aged 8-10 years in five provinces representing the different ecological zones of the country - Kabul, Balkh, Herat, Nangarhar and Kandahar. Microscopic examination was carried out by the Kato-Katz thick smear technique, to assess the presence and the number of parasites and/or their eggs. The survey revealed that 26.6% of the sample was infected with at least one of the STH, a marked decrease from the level registered in 2003. The most prevalent infection was the one with A. lumbricoides (25.7%), followed by T. trichiura (1.0%) and hookworms (0.1%). All positive children were noted to have light-intensity infections, compared to the previous survey where 9.7% of the sample had moderate-to-heavy intensity infections. Only 0.2% of the children had co-infection with two or more parasites. Meanwhile, 6.8% of the students were found infected with the dwarf tapeworm, Hymenolepis nana. The absence of infections of moderate-to-heavy intensity after several yearly rounds of deworming and overall improvements in provision of safe water and sanitation, indicates successful control of morbidity due to STH and, overall, their elimination as a public-health problem from Afghanistan. Nevertheless, current levels of prevalence of infection still show persistence of active transmission of STHs, thus justifying the continued implementation of mass deworming interventions among children. The permanent elimination of STH transmission, however, will be possible only when the country reaches a sanitation level sufficient to impede fecal contamination of the environment with human excreta.

Hymenolepis nana-An Emerging Intestinal Parasite Associated with Anemia in School Children from the Bolivian Chaco.

Tropical anemia can have multiple causes, whether socioeconomic, dietary, or infectious. In the Bolivian Chaco, soil-transmitted helminthiases (STH), malaria, and Chagas disease are potential infectious causes of anemia among school-aged children (SAC). Following years of preventive chemotherapy with mebendazole, the prevalence of STH among SAC living in that area is now negligible, whereas protozoan infections are still highly prevalent (81%); Hymenolepis nana is the most frequent intestinal helminth (∼13%). We present results of hemoglobin (Hb) assessment and the association between parasitic infections and Hb levels of that SAC population. Overall, 511 SAC (girls:boys ratio 1:1, mean age 9.4 years [95% confidence interval {CI}: 9.3-9.5]) had Hb levels measured by using a point of care testing (HemoCue® Hb 301 System; HemoCue, Angelhome, Sweden). The prevalence of anemia was 23% (117/511), with mean and median Hb level = 12.2 g/dL (95% CI: 12.1-12.3; range 9.2-15.4 g/dL). By multivariate analysis, H. nana infection was associated with an increased risk of anemia (odds ratio 2.9, 95% CI: 1.5-5.7, P = 0.002). Two samples (0.5%) were positive for Trypanosoma cruzi and none for Plasmodium spp. by polymerase chain reaction of the 439 children tested. Anemia is still a concern among SAC living in the Bolivian Chaco. Our findings call for a greater attention to fecal-oral emerging pathogens, such as H. nana, and highlight the importance of water, sanitation, and hygiene improvements for disadvantaged population such as those living in the Bolivian Chaco.

Rodent-borne diseases and their public health importance in Iran.

BACKGROUND: Rodents are reservoirs and hosts for several zoonotic diseases such as plague, leptospirosis, and leishmaniasis. Rapid development of industry and agriculture, as well as climate change throughout the globe, has led to change or increase in occurrence of rodent-borne diseases. Considering the distribution of rodents throughout Iran, the aim of this review is to assess the risk of rodent-borne diseases in Iran. METHODOLOGY/PRINCIPAL FINDING: We searched Google Scholar, PubMed, Science Direct, Scientific Information Database (SID), and Magiran databases up to September 2016 to obtain articles reporting occurrence of rodent-borne diseases in Iran and extract information from them. Out of 70 known rodent-borne diseases, 34 were reported in Iran: 17 (50%) parasitic diseases, 13 (38%) bacterial diseases, and 4 (12%) viral diseases. Twenty-one out of 34 diseases were reported from both humans and rodents. Among the diseases reported in the rodents of Iran, plague, leishmaniasis, and hymenolepiasis were the most frequent. The most infected rodents were Rattus norvegicus (16 diseases), Mus musculus (14 diseases), Rattus rattus (13 diseases), Meriones persicus (7 diseases), Apodemus spp. (5 diseases), Tatera indica (4 diseases), Meriones libycus (3 diseases), Rhombomys opimus (3 diseases), Cricetulus migratorius (3 diseases), and Nesokia indica (2 diseases). CONCLUSIONS/SIGNIFICANCE: The results of this review indicate the importance of rodent-borne diseases in Iran. Considering notable diversity of rodents and their extensive distribution throughout the country, it is crucial to pay more attention to their role in spreading infectious diseases for better control of the diseases.

Albendazole in the treatment of Hymenolepiasis in school children.

Hymenolepiasis is a helminthic and occasionally fatal disease of human imposing heavy economic losses to human society. Present study was aimed to diagnose the school children for the prevalence and control of Hymenolepiasis. A school based cross-sectional analysis of stool samples collected from 188 children aged 06-15 years was carried out (February to June 2016). Two stool samples were collected from each student before diagnosing and after treatment. The samples were fixed in 10% formalin and observed under the light microscope using the methods of direct smear in Lugol's solution, normal saline and flotation techniques. On the basis of drugs accessibility all the H. nana infected children were divided in to 2- groups. Children in group A were treated with albendazole (bendazol) 400mg once orally, group B was treated with albendazole (zentel) 200mg orally. Eggs per gram of faeces were counted in each group before and after treatment. Of the 188 children, current study reveals only 6.08% (n=18/296) infection with H.nana and 10.5% (n=16/151) were diagnosed with co infections. The % efficacy of albendazole (Zentel) and albendazole (bendazol) against Hymenolepis nana infection was reported as 83% and 75% respectively. Present study was concluded that albendazole (zentel) is the drug of choice for the treatment of hymenolepiasis in children.

The role of chewing lice (Phthiraptera: Philopteridae) as intermediate hosts in the transmission of Hymenolepis microps (Cestoda: Cyclophyllidea) from the willow ptarmigan Lagopus lagopus (Aves: Tetraonidae).

The cestode Hymenolepis microps is an intestinal parasite of tetraonid birds, including the willow ptarmigan (Lagopus lagopus). This parasite is able to maintain a high prevalence and intensity throughout the year, even in a subarctic environment in bird populations with relatively low host densities, indicating effective transmission routes. Willow ptarmigan consume mainly vegetal material and active consumption of invertebrates is confined to the first two or three weeks of life. Ptarmigan are infected by different species of ectoparasites, of which two species of feather lice, Lagopoecus affinis and Goniodes lagopi, are the most abundant. In this study, we explored the hypothesis that feather lice may be suitable intermediate hosts for H. microps. We applied histological techniques and light microscopy to investigate lice for the presence of larval cestode stages (cysticercoids). We found 12 cysticercoid-like structures inside chewing lice collected on L. lagopus hosts harbouring H. microps. In addition, a polymerase chain reaction (PCR) screening of Ischnocera lice DNA, targeting the 18S rRNA gene of the cestode, showed positive results for two different short fragments of the 18S rRNA gene of H. microps which were sequenced from lice collected on birds. Both independent lines of evidence support the hypothesis that Ischnocera lice might be suitable intermediate hosts in the life cycle of H. microps in L. lagopus.

Prevalence, Age Profile, and Associated Risk Factors for Hymenolepis nana Infection in a Large Population-Based Study in Northern Peru.

Hymenolepis nana, the dwarf tapeworm, is a common intestinal infection of children worldwide. We evaluated infection and risk factor data that were previously collected from 14,761 children aged 2-15 years during a large-scale program in northern Peru. We found that 1,124 of 14,761 children (7.61%) had H. nana infection, a likely underestimate given that only a single stool sample was examined by microscopy for diagnosis. The strongest association with infection was lack of adequate water (adjusted prevalence ratio [aPR] 2.22, 95% confidence interval [CI] 1.82-2.48) and sanitation infrastructure in the house (aPR 1.94, 95% CI 1.64-2.29). One quarter of those tested did not have a bathroom or latrine at home, which doubled their likelihood of infection. Similarly, one quarter did not have piped public water to the house, which also increased the likelihood of infection. Continued efforts to improve access to basic water and sanitation services will likely reduce the burden of infection in children for this and other intestinal infections.

Case Report: A Symptomatic Case of Hymenolepis diminuta Infection in an Urban-Dwelling Adult in Malaysia.

A case of Hymenolepis diminuta infection in a 43-year-old Malaysian male with persistent abdominal colicky pain is reported. Endoscopy revealed whitish worms in the lumen of the small intestine, which were identified as H. diminuta after microscopy. Patient was successfully treated with a single dose of praziquantel (25 mg/kg).

Prevalence of Hymenolepis nana and H. diminuta from Brown Rats (Rattus norvegicus) in Heilongjiang Province, China.

Hymenolepis nana and Hymenolepis diminuta are globally widespread zoonotic cestodes. Rodents are the main reservoir host of these cestodes. Brown rats (Rattus norvegicus) are the best known and most common rats, and usually live wherever humans live, especially in less than desirable hygiene conditions. Due to the little information of the 2 hymenolepidid species in brown rats in China, the aim of this study was to understand the prevalence and genetic characterization of H. nana and H. diminuta in brown rats in Heilongjiang Province, China. Total 114 fecal samples were collected from brown rats in Heilongjiang Province. All the samples were subjected to morphological examinations by microscopy and genetic analysis by PCR amplification of the mitochondrial cytochrome c oxidase subunit 1 (COX1) gene and the internal transcribed spacer 2 (ITS2) region of the nuclear ribosomal RNA gene. In total, 6.1% (7/114) and 14.9% (17/114) of samples were positive for H. nana and H. diminuta, respectively. Among them, 7 and 3 H. nana isolates were successfully amplified and sequenced at the COX1 and ITS2 loci, respectively. No nucleotide variations were found among H. nana isolates at either of the 2 loci. Seventeen H. diminuta isolates produced 2 different COX1 sequences while 7 ITS2 sequences obtained were identical to each other. The present results of H. nana and H. diminuta infections in brown rats implied the risk of zoonotic transmission of hymenolepiasis in China. These molecular data will be helpful to deeply study intra-specific variations within Hymenolepis cestodes in the future.

A survey of zoonotic pathogens carried by house mouse and black rat populations in Yucatan, Mexico.

The house mouse (Mus musculus) and the black rat (Rattus rattus) are reservoir hosts for zoonotic pathogens, several of which cause neglected tropical diseases (NTDs). Studies of the prevalence of these NTD-causing zoonotic pathogens, in house mice and black rats from tropical residential areas are scarce. Three hundred and two house mice and 161 black rats were trapped in 2013 from two urban neighbourhoods and a rural village in Yucatan, Mexico, and subsequently tested for Trypanosoma cruzi, Hymenolepis diminuta and Leptospira interrogans. Using the polymerase chain reaction we detected T. cruzi DNA in the hearts of 4·9% (8/165) and 6·2% (7/113) of house mice and black rats, respectively. We applied the sedimentation technique to detect eggs of H. diminuta in 0·5% (1/182) and 14·2% (15/106) of house mice and black rats, respectively. Through the immunofluorescent imprint method, L. interrogans was identified in 0·9% (1/106) of rat kidney impressions. Our results suggest that the black rat could be an important reservoir for T. cruzi and H. diminuta in the studied sites. Further studies examining seasonal and geographical patterns could increase our knowledge on the epidemiology of these pathogens in Mexico and the risk to public health posed by rodents.

Effect of Mass Stool Examination and Mass Treatment For Decreasing Intestinal Helminth and Protozoan Infection Rates in Bolivian Children: A Cross-Sectional Study.

Bolivia is one of the countries with a high intestinal helminth and protozoan infection rate. Despite the high prevalence of the parasitic infection, nationwide preventive measures for Bolivian children have not yet been implemented. We evaluated the effect of mass stool examination and treatment as a strategy for decreasing the infection rate. This study was conducted between 2013 and 2015 in children aged 2-18 years. A total of 2,033 stool samples (575 in 2013, 815 in 2014 and 642 in 2015) were collected and examined using the formalin-ether medical sedimentation method. As an anthelminthic medicine, nitazoxanide was given to all infected children within 2 months post-examination, each year. The effect of mass stool examination and treatment was evaluated based on the changes in the overall or individual parasitic infection rates during the study period. The overall parasitic infection rate decreased significantly from 65.2% in 2013 to 43.0% in 2015; a 22.2 percentage point decrease (P<0.001). Protozoan infection accounted for a large portion of the parasitic infections, in the following rates: 62.4% in 2013, 49.3% in 2014, and 41.0% in 2015. The rate of the most common helminth infection, Hymenolepis nana, decreased significantly from 9.0% in 2013 to 6.4% in 2014 to 3.4% in 2015 (P<0.001). Prevalence of the most common pathogenic protozoan infection, Entamoeba histolytica, decreased significantly from 19.0% in 2013 to 3.0% in 2015 (P<0.001). Conversely, the rate of Giardia intestinalis increased significantly from 16.5% in 2013 to 21.2% in 2015 (P<0.01). Mass stool examination and treatment for intestinal helminth and protozoan infections was effective for decreasing the overall parasitic infection rate in the study population, excluding Giardia intestinalis. Further studies on the long-term effect of mass stool examination and treatment for decreasing all intestinal parasitic infection rates in Bolivian children are needed.

Parasites and invasions: changes in gastrointestinal helminth assemblages in invasive and native rodents in Senegal.

Understanding why some exotic species become widespread and abundant in their colonised range is a fundamental issue that still needs to be addressed. Among many hypotheses, newly established host populations may benefit from a parasite loss ("enemy release" hypothesis) through impoverishment of their original parasite communities or reduced infection levels. Moreover, the fitness of competing native hosts may be negatively affected by the acquisition of exotic taxa from invaders ("parasite spillover") and/or by an increased transmission risk of native parasites due to their amplification by invaders ("parasite spillback"). We focused on gastrointestinal helminth communities to determine whether these predictions could explain the ongoing invasion success of the commensal house mouse (Mus musculus domesticus) and black rat (Rattus rattus), as well as the associated decrease in native Mastomys spp., in Senegal. For both invasive species, our results were consistent with the predictions of the enemy release hypothesis. A decrease in overall gastrointestinal helminth prevalence and infracommunity species richness was observed along the invasion gradients as well as lower specific prevalence/abundance (Aspiculuris tetraptera in Mus musculus domesticus, Hymenolepis diminuta in Rattus rattus) on the invasion fronts. Conversely, we did not find strong evidence of GIH spillover or spillback in invasion fronts, where native and invasive rodents co-occurred. Further experimental research is needed to determine whether and how the loss of gastrointestinal helminths and reduced infection levels along invasion routes may result in any advantageous effects on invader fitness and competitive advantage.

Hymenolepis nana Impact Among Children in the Highlands of Cusco, Peru: An Emerging Neglected Parasite Infection.

Hymenolepis nana is the most common cestode infection in the world. However, limited information is available regarding its impact on affected populations. We studied the epidemiology and symptoms associated with hymenolepiasis among children 3-16 years old in 16 rural communities of the highlands of the Cusco region in Peru. Information on demographics, socioeconomic status, symptoms as reported by parents, and parasitological testing was obtained from the database of an ongoing Fasciola hepatica epidemiologic study. A total of 1,230 children were included in the study. Forty-five percent were infected with at least one pathogenic intestinal parasite. Giardia spp. (22.9%) was the most common, followed by Hymenolepis (17.4%), Fasciola (14.1%), Ascaris lumbricoides (6.1%), and Strongyloides stercoralis (2%). The prevalence of Hymenolepis infection varied by community, by other parasitic infections, and by socioeconomic status. However, only years of education of the mother, use of well water, and age less than 10 years were associated with Hymenolepis infection in the multivariate analysis. Hymenolepis nana infection was associated with diarrhea, jaundice, headaches, fever, and fatigue. Children with > 500 eggs/g of stool were more likely to have symptoms of weight loss, jaundice, diarrhea, and fever. Hymenolepis nana infection and age were the only factors retained in the multivariate analysis modeling diarrhea. Hymenolepiasis is a common gastrointestinal helminth in the Cusco region and is associated with significant morbidity in children in rural communities. The impact caused by the emergence of Hymenolepis as a prevalent intestinal parasite deserves closer scrutiny.

School-based prevalence of intestinal parasitic infections and associated risk factors in rural communities of Sana'a, Yemen.

Yemen is a developing country overwhelmed with a triad of poverty, diseases and social conflicts. Moreover, the majority of its population live in rural communities and suffer from intestinal parasitic infections (IPIs). Therefore, the present school-based, cross-sectional survey aimed to detect the prevalence of such infections and associated risk factors among schoolchildren in the rural communities of Bani Alharith, Hamdan and Bani Hushaysh districts of Sana'a, north of Yemen. Socio-demographic data and certain behavioral risk factors as well as stool samples were collected from 1218 schoolchildren from ten randomly schools in the study area. Fresh stool samples were examined for parasites by direct saline and iodine preparations and after concentration with formol-ether technique. The overall prevalence of IPIs was 54.8%, with a higher frequency of protozoal than helminthic infections (37.6 vs. 17.2%, respectively). Parasite species recovered were Entameba histolytica (21.5%), Giardia lamblia (16.1%), Ascaris lumbricoides (8.3%), Hymenolepis nana (5.3%), Schistosoma mansoni (2.6%), Trichuris trichiura (0.5%) and Enterobius vermicularis (0.4%). Univariate analysis showed that the male gender and illiteracy of fathers and/or mothers were the socio-demographic factors significantly associated with higher infection rates. The illiteracy of mothers was also confirmed as an independent risk factor by multivariable analysis. On the other hand, not washing hands before eating, not washing fruits and vegetables before consumption, eating uncovered food and not clipping fingernails were the risk behaviors significantly associated with higher infection rates, with the last three ones being confirmed as independent risk factors. Therefore, control measures should include regular treatment of protozoal infections and deworming of schoolchildren, promotion of hygiene in rural schools through health education programs, regular inspection of schoolchildren for personal hygiene practices and the provision of a healthy school infrastructure.

Infección por Hymenolepis nana en una comunidad indígena del estado Bolívar, Venezuela / Hymenolepis nana infection in an indigenous community from Bolívar State, Venezuela

Introducción: la himenolepiosis es una parasitosis intestinal causada por el género Hymenolepis. De las dos especies que pueden afectar al hombre, H. nana es la más común. Su distribución es cosmopolita, pero más frecuente en regiones tropicales. Objetivos: en junio de 2014 se realizó un estudio transversal para determinar la prevalencia de himenolepiosis en habitantes de la comunidad indígena Itopoicon del estado Bolívar, Venezuela. Métodos: fueron evaluadas 136 muestras fecales procedentes de igual número de personas, mediante las técnicas de examen directo, Kato, Willis y sedimentación espontánea. Se llenó una ficha de control de cada participante con datos de identificación y clínico-epidemiológicos de interés. Resultados: un total de 118 habitantes (86,8 por ciento) resultaron parasitados. De ellos, 26 (19,1 por ciento) tenían infección por helmintos intestinales, siendo Hymenolepis nana el helminto más comúnmente diagnosticado con 19 casos (14 por ciento). De los 19 casos de himenolepiosis, 17 ocurrieron en niños y dos en adultos, siendo la diferencia estadísticamente significativa (x2= 14,26 g.l.= 7 p< 0,05). Con relación al género no se observaron diferencias estadísticamente significativas (p> 0,05). Se determinó una amplia variedad de manifestaciones clínicas (generales, toxico-alérgico o intestinales) en los habitantes con H. nana. Conclusiones: se determinó una elevada prevalencia (14 por ciento) de infección por H. nana en una comunidad indígena del estado Bolívar, Venezuela, siendo ambos géneros afectados por igual pero con un predominio en los niños menores de 10 años. La mayoría de los casos presentó sintomatología(AU)

Introduction: hymenolepiasis is an intestinal parasitic disease caused by the genus Hymenolepis. Of the two species affecting humans, H. nana is the most common. Its distribution is cosmopolitan, but more frequent in tropical regions. Objectives: a cross-sectional study was conducted in June 2014 to determine the prevalence of hymenolepiasis among dwellers from the indigenous community of Itopoicon, Bolívar State, Venezuela. Methods: evaluation was performed of 136 stool samples from an equal number of persons using the techniques known as direct examination, Kato, Willis and spontaneous sedimentation. A control card was filled in for each participant, containing identification details and data of clinical and epidemiological interest. Results: a total 118 inhabitants (86.8 percent) were positive for parasites. Of these, 26 (19.1 percent) had intestinal helminth infection, Hymenolepis nana being the most commonly diagnosed helminth with 19 cases (14 percent). Of the 19 cases of hymenolepiasis, 17 were children and 2 were adults, the difference being statistically significant (2= 14.26 g.l. = 7 p< 0.05). No statistically significant differences were found with respect to gender (p> 0.05). A wide range of clinical manifestations (general, toxic and allergic or intestinal) were found among people with H. nana. Conclusions: ahigh prevalence (14 percent) of H. nana infection was found in an indigenous community from Bolívar State in Venezuela. Both sexes are equally affected, but there is a predominance of children under 10 years of age. Most cases were symptomatic(AU)

Infection levels of the cestode Hymenolepis diminuta in rat populations from Buenos Aires, Argentina.

Ecological studies on zoonotic parasites are crucial for the design and implementation of effective measures to prevent parasite transmission. The aim of this study was to evaluate factors such as season, landscape unit, rat sex and rat body length, affecting the abundance of the cestode Hymenolepis diminuta, a parasite of synanthropic rats, within an urban environment. A parasitological survey was undertaken on 169 rats from landscape units such as shantytowns, parklands, industrial-residential areas and scrap-metal yards in Buenos Aires, Argentina. The overall prevalence of H. diminuta was 21.3%, although the occurrence of this species in rats was not homogeneous. The abundance of H. diminuta, using a zero-inflated negative binomial model, was correlated with rat body length. In shantytowns, abundance levels were higher than other landscape units, largely due to differences in individual environmental characteristics and rat assemblages. The populations of arthropod intermediate hosts could be subjected to seasonal fluctuations and the degree of urbanization. Shantytowns are overcrowded urban marginal settlements with most inhabitants living in precarious conditions and supporting large populations of rats, thereby increasing the risk of zoonotic infection.