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.

First survey on zoonotic helminthosis in urban brown rats (Rattus norvegicus) in Spain and associated public health considerations.

The brown rat, Rattus norvegicus, with a worldwide distribution, is the most commensal species among synanthropic rodents, since its main habitat, in urban as well as in rural areas, is always linked to humans. Therefore, people living in close proximity to rodent populations can be exposed to infection. Whereas bacteria and viruses are the best known rat-associated zoonoses in urban environments, the role of brown rats as reservoirs for helminth parasites and the associated risk for humans are less well known. Specifically, this role has not been analyzed in Spain to date. A total of 100 R. norvegicus trapped in the sewage system (n = 85), and parks (n = 15) of Barcelona was examined. The overall prevalence of helminth infection was 85%. The helminths found were Hymenolepis nana (17%), H. diminuta (33%) (Cestoda), Calodium hepaticum (17%), Eucoleus gastricus (28%), Aonchotheca annulosa (12%), Trichosomoides crassicauda (7%), Nippostrongylus brasiliensis (46%), Heterakis spumosa (62%), Gongylonema neoplasticum (20%) (Nematoda) and Moniliformis moniliformis (6%) (Acanthocephala). Five of the ten helminth species are considered zoonotic parasites, with rats acting as reservoirs for human infection, i.e. H. nana, H. diminuta, C. hepaticum, G. neoplasticum and M. moniliformis. G. neoplasticum and M. moniliformis are reported for the first time in urban rats in Europe. H. nana, H. diminuta and C. hepaticum are the most widespread species in European cities. For H. nana and C. hepaticum, rats act as effective spreaders of the human infective stage (eggs). For H. diminuta, G. neoplasticum and M. moniliformis, rats act as indirect reservoirs of the zoonoses since the eggs shed by the rats are infective for their insect intermediate hosts only. Medical practitioners need to be made aware of the range of parasites carried by rats, as there is a realistic likelihood that ill health currently caused by rat infestations may be misdiagnosed.

Foodborne Giardiasis: Is There Any Relationship Between food Handlers and Transmission of Giardia duodenalis?

BACKGROUND: The foodborne diseases are amongst the main causes of morbidity and mortality in the human communities. Giardia duodenalis, the causative agent of giardiasis, is one of the foodborne parasites, which has public health importance. The aim of the current study was to assess the prevalence of G. duodenalis among food handlers in Andimeshk County, southwest of Iran. MATERIALS AND METHODS: This cross-sectional study was undertaken among 480 food handlers in 2015. The collected stool specimens were investigated using direct saline smear, Lugol's iodine- staining, and sucrose flotation methods. RESULTS: The overall prevalence of G. duodenalis in the examined participants was 12 (2.5%). The higher prevalence 75% (9/12) was found among participants with medium and low levels of education and 25% (3/12) belonged to those with high level of education. Direct microscopic examinations revealed two (0.4%) positive cases infected with Hymenolepis nana, with one of them showing mixed infection with G. duodenalis. CONCLUSION: Based on the obtained results, infected food handlers could be a potential source of intestinal parasitic infections, and transmission can occur through contaminated food. Therefore, we suggest that food handlers training programs should be implemented to increase the awareness of food handlers and reduce the transmission of intestinal parasites.

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.

Insights on the host associations and geographic distribution of Hymenolepis folkertsi (Cestoda: Hymenolepididae) among rodents across temperate latitudes of North America.

Synoptic data and an understanding of helminth parasite diversity among diverse rodent assemblages across temperate latitudes of North America remain remarkably incomplete. Renewed attention to comprehensive survey and inventory to establish the structure of biodiverse faunas is essential in providing indicators and proxies for identifying the outcomes of accelerating change linked to climate warming and anthropogenic forcing. Subsequent to the description of Hymenolepis folkertsi in the oldfield mouse, Peromyscus polionotus, additional specimens of hymenolepidids were collected or discovered in archived museum repositories from multiple species of deer mice (Peromyscus maniculatus, Peromyscus leucopus), the golden mouse (Ochrotomys nuttalli), chipmunks (Tamias striatus, Tamias amoenus), the 13-lined ground squirrel (Ictidomys tridecemlineatus), and tree squirrels (Sciurus carolinensis, Sciurus niger) from disjunct localities in the USA spanning southern Georgia, Virginia, Pennsylvania, Connecticut, the Upper Peninsula of Michigan, Wisconsin, and central Idaho. Specimens were largely consistent morphologically with the original description of H. folkertsi. Initial DNA sequence data, from a portion of the mitochondrial NADH dehydrogenase subunit 1, demonstrated intraspecific variation among three apparently geographically isolated populations attributed to H. folkertsi (uncorrected genetic distances of 2.7 % (Idaho and Michigan), 2.4 % (Virginia + Pennsylvania and Michigan), and 1.89 % (VA + PA and ID). Geography rather than host association explains the distribution and occurrence of H. folkertsi, and host colonization among deer mice, chipmunks, and other sciurids within regional sites is indicated. Genetic divergence revealed across localities for H. folkertsi suggests historically isolated populations, consistent with extended evolutionary and biogeographic trajectories among hymenolepidids and species of Peromyscus and Tamias in North America. Field inventory, that revealed these parasite populations, substantially alters our understanding of the distribution of diversity and provides insights about the nature of the complex relationships that serve to determine cestode faunas in rodents.

Cryptic diversity in hymenolepidid tapeworms infecting humans.

An adult hymenolepidid tapeworm was recovered from a 52-year-old Tibetan woman during a routine epidemiological survey for human taeniasis/cysticercosis in Sichuan, China. Phylogenetic analyses based on sequences of nuclear 28S ribosomal DNA and mitochondrial cytochrome c oxidase subunit 1 showed that the human isolate is distinct from Hymenolepis diminuta and Hymenolepis nana, the common parasites causing human hymenolepiasis. Proglottids of the human isolate were unfortunately unsuitable for morphological identification. However, the resultant phylogeny demonstrated the human isolate to be a sister species to Hymenolepis hibernia from Apodemus mice in Eurasia. The present data clearly indicate that hymenolepidid tapeworms causing human infections are not restricted to only H. diminuta and H. nana.

Survey of Hymenolepis spp. in pet rodents in Italy.

We carried out the first survey of Hymenolepis spp. infection in pet rodents in Italy. Fresh fecal samples were collected from 172 pet rodents as follows: guinea pigs (Cavia porcellus; n = 60), squirrels (Callosciurus finlaysonii, Callosciurus prevosti, Tamias striatus, Tamias sibiricus, Sciurus calorinensis; n = 52), hamsters (Phodopus campbelli, Mesocricetus auratus; n = 30), chinchillas (Chinchilla lanigera; n = 13), rats (Rattus norvegicus; n = 10), and mice (Mus minutoides; n = 7). These animals were housed either in pet shops or in private houses. All fecal samples were processed using the FLOTAC pellet technique to assess the number of eggs per gram (EPG) of feces. Eggs of Hymenolepis nana were found in 24 out of 172 (13.9 %; 95 % confidence interval = 9.3-20.2 %) pet rodents. Of those rodents, 41.6 % (10/24) were rats (mean EPG = 55.7; range = 2-200), 29.2 % (7/24) mice (mean EPG = 64.5; range = 32-120), 25.0 % (6/24) were chinchillas (mean EPG = 25.5; range = 10-50), and 4.2 % (1/24) hamsters (P. campbelli) (EPG = 86.0). In addition, Hymenolepis diminuta eggs were found in 2 out of 172 (1.2 %; 95 % confidence interval = 0.2-4.6 %) rodents examined, both of which (100 %; 2/2) were pet squirrels (C. prevosti) (mean EPG = 10; range = 4-16). To the authors' knowledge, this is the first report of a natural infection of H. diminuta in pet squirrels.

Hymenolepis folkertsi n. sp. (Eucestoda: Hymenolepididae) in the oldfield mouse Peromyscus polionotus (Wagner) (Rodentia: Cricetidae: Neotominae) from the southeastern Nearctic with comments on tapeworm faunal diversity among deer mice.

A previously unrecognized species of hymenolepidid cestode attributable to Hymenolepis is described based on specimens in Peromyscus polionotus, oldfield mouse, from Georgia near the southeastern coast of continental North America. Specimens of Hymenolepis folkertsi n. sp. differ from those attributed to most other species in the genus by having testes arranged in a triangle and a scolex with a prominent rostrum-like protrusion. The newly recognized species is further distinguished by the relative position and length of the cirrus sac, shape of seminal receptacle, and relative size of external seminal vesicle and seminal receptacle. Hymenolepidid cestodes have sporadically been reported among the highly diverse assemblage of Peromyscus which includes 56 distinct species in the Nearctic. Although the host genus has a great temporal duration and is endemic to the Nearctic, current evidence suggests that tapeworm faunal diversity reflects relatively recent assembly through bouts of host switching among other cricetid, murid, and geomyid rodents in sympatry.

Description of two new species of Hymenolepis Weinland, 1858 (Cestoda: Hymenolepididae) from rodents on Luzon Island, Philippines.

Our helminthological examination of murid rodents on Luzon Island, Philippines, revealed a remarkable diversity of Hymenolepis Weinland, 1858. Here we describe two new species based on specimens from murid rodents Rattus everetti (Günther) and Apomys datae (Meyer) collected from Luzon Island. Hymenolepis alterna n. sp. differs from all known species of Hymenolepis in having irregularly alternating genital pores. This feature has not been reported from any previously known member of Hymenolepis. Additionally, Hymenolepis alterna n. sp. also differs from other Hymenolepis spp. in the relative position of both poral and antiporal dorsal osmoregulatory canals which are shifted towards the middle of the proglottis in relation to the ventral canals on both sides of the proglottides, and in having curved or twisted external seminal vesicle, covered externally by a dense layer of intensely stained cells. Hymenolepis bilaterala n. sp. differs from all known species of Hymenolepis in the relative position of both poral and antiporal dorsal osmoregulatory canals, which are shifted bilaterally towards the margins of proglottides in relation to the ventral canals, and in possession of testes situated in a triangle and eggs with very thin outer coat. A total of seven species of Hymenolepis are known from the Philippine archipelago. This total includes the cosmopolitan species Hymenolepis diminuta (Rudolphi, 1819), which was likely introduced to the island with invasive rats. Strikingly, all seven known species occur on the island of Luzon alone. By comparison, only six Hymenolepis spp. are known from the whole Palaearctic and seven from the Nearctic despite a much better level of knowledge of rodent helminths in these zoogeographical regions, as well as vast territories, diverse landscapes and very rich rodent fauna. This suggests that Hymenolepis spp. may have undergone an unusually active radiation in the Philippines. Possible explanations of this phenomenon are discussed.

Helminth parasites in the endangered Ethiopian wolf, Canis simensis.

Ethiopian wolves, Canis simensis, are an endangered carnivore endemic to the Ethiopian highlands. Although previous studies have focused on aspects of Ethiopian wolf biology, including diet, territoriality, reproduction and infectious diseases such as rabies, little is known of their helminth parasites. In the current study, faecal samples were collected from 94 wild Ethiopian wolves in the Bale Mountains of southern Ethiopia, between August 2008 and February 2010, and were screened for the presence of helminth eggs using a semi-quantitative volumetric dilution method with microscopy. We found that 66 of the 94 faecal samples (70.2%) contained eggs from at least one group of helminths, including Capillaria, Toxocara, Trichuris, ancylostomatids, Hymenolepis and taeniids. Eggs of Capillaria sp. were found most commonly, followed by Trichuris sp., ancylostomatid species and Toxocara species. Three samples contained Hymenolepis sp. eggs, which were likely artefacts from ingested prey species. Four samples contained taeniid eggs, one of which was copro-polymerase chain reaction (copro-PCR) and sequence positive for Echinococcus granulosus, suggesting a spillover from a domestic parasite cycle into this wildlife species. Associations between presence/absence of Capillaria, Toxocara and Trichuris eggs were found; and egg burdens of Toxocara and ancylostomatids were found to be associated with geographical location and sampling season.

Sanitation ability of anaerobic digestion performed at different temperature on sewage sludge.

A small amount of ammonia is used in full-scale plants to partially sanitize sewage sludge, thereby allowing successive biological processes to enable the high biological stability of the organic matter. Nevertheless, ammonia and methane are both produced during the anaerobic digestion (AD) of sludge. This paper describes the evaluation of a lab-scale study on the ability of anaerobic process to sanitize sewage sludge and produce biogas, thus avoiding the addition of ammonia to sanitize sludge. According to both previous work and a state of the art full-scale plant, ammonia was added to a mixture of sewage sludge at a rate so that the pH values after stirring were 8.5, 9 and 9.5. This procedure determined an ammonia addition lower than that generally indicated in the literature. The same sludge was also subjected to an AD process for 60 days under psychrophilic, mesophilic and thermophilic conditions. The levels of fecal coliform, Salmonella spp. helmints ova, pH, total N, ammonia fractions and biogas production were measured at different times during each process. The results obtained suggested that sludge sanitation can be achieved using an AD process; however, the addition of a small amount of ammonia was not effective in sludge sanitation because the buffer ability of the sludge reduced the pH and thus caused ammonia toxicity. Mesophilic and thermophilic AD sanitized better than psychrophilic AD did, but the total free ammonia concentration under the thermophilic condition inhibited biogas production. The mesophilic condition, however, allowed for both sludge sanitation and significant biogas production.

Two new species of Hymenolepis (Cestoda: Hymenolepididae) from murid rodents (Rodentia: Muridae) in the Philippines.

Two previously unrecognized species of the genus Hymenolepis are described based on specimens obtained from murid rodent species Bullimus luzonicus , Apomys microdon , and Rattus everetti collected on Luzon Island, Philippines. Hymenolepis bicauda n. sp. differs from all known Hymenolepis spp. in relative position of the poral dorsal and ventral osmoregulatory canals, gravid uterus occupying less than half the length of proglottid, relatively few eggs, and the highly characteristic longitudinal split of proglottids at the end of the gravid strobila. Hymenolepis haukisalmii n. sp. differs from all known Hymenolepis spp. in the relative position of both poral and aporal dorsal and ventral osmoregulatory canals and uterus lacking dorsal and ventral diverticula. The shift in the relative position of the dorsal and ventral osmoregulatory canals was not known in Hymenolepis from rodents in other regions of the world and is reminiscent of the situation observed in Hymenolepis erinacei, parasitic in hedgehogs, and members of the genus Talpolepis, parasitic in moles. The cosmopolitan species Hymenolepis diminuta was the only member of the genus previously reported from the Philippines.

FLOTAC for the diagnosis of Hymenolepis spp. infection: proof-of-concept and comparing diagnostic accuracy with other methods.

Hymenolepis nana is the most common cestode parasitizing humans, yet it is under-diagnosed. We determined the optimal flotation solution (FS) for the diagnosis of this intestinal parasite with the FLOTAC method, and compared its diagnostic accuracy with an ether-concentration technique and the Kato-Katz method. Zinc sulphate (specific gravity 1.20) proved to be the best-performing FS. Using this FS, we detected 65 H. nana infections among 234 fixed fecal samples from Tajik and Sahrawi children (prevalence 27.8 %). The ether-concentration technique detected 40 infections (prevalence 17.1 %) in the same samples. Considering the combined results as a reference, the sensitivities of FLOTAC and ether-concentration were 95.6 % and 58.8 %, respectively. The Kato-Katz method resulted in a prevalence of only 8.7 %. In terms of eggs per gram of stool, a significantly (P <0.05) higher value was obtained with the FLOTAC and Kato-Katz techniques compared to ether-concentration. In another study carried out in China, the FLOTAC method detected six Hymenolepis diminuta infections in 302 fecal samples, whereas five samples were found positive with the Kato-Katz technique. We conclude that FLOTAC is an accurate coprodiagnostic technique for H. nana and H. diminuta, two species which join a growing list of intestinal parasites that can be reliably diagnosed by this technique.

Tapeworms of rock dove and domestic chicken in Taif area, Saudi Arabia.

The present study aimed to identify the tapeworms that parasitize the rock dove Columba livia palastinae and domestic chicken Gallus gallus domesticus in Taif governorate, Saudi Arabia. A total of 115 rock doves and 105 domestic chicken have been examined. Birds were brought in from the wells and farms inside and outside the city of Taif. In rock doves, the percentage of infection was recorded as Cotugnia digonopora 5.21%, Hymenolepis carioca 10.43%, Raillietina echinobothrida 27.82%, Raillietina tetragona 22.6%. The prevalence of infection recorded in Municipal chicken with different types of tapeworms was Cotugnia digonopora 7.61%, Choanotaenia infundibulum 12.38%, Amoebotaenia sphenoides 7.61%, Raillietina echinobothrida 11.42%, Raillietina tetragona 8.57%, Raillietina (Paroniella) kashiwarensis 4.76%. The overall percentage of infected rock pigeons Columba livia palastinae with tapeworms was 66.1% while the percentage of infected chicken Gallus gallus domestica was 52.3%. The study defined and described this species as classification keys in place.

Morphological features of Cloacotaenia megalops (Nitzsch in Creplin, 1829) (Cestoda, Hymenolepididae) from different hosts.

The tapeworm species Cloacotaenia megalops (Nitzsch in Creplin, 1829) is characterized by a very specific morphology. A particularly distinct feature is a large almost square scolex in which four fleshy suction cups are embedded and a rudimentary rostellum. During standard studies of wild duck cestode fauna in northwestern Poland, some morphological differences were observed among specimens, mainly in the shape of scolices and hermaphroditic proglottids of C. megalops isolated from different bird species. This paper attempts to demonstrate the impact of the host species on morphology of the parasite. The study material consisted of 39 individuals of C. megalops (19 from Aythya fuligula, 10 from Anas platyrhynchos, 4 from Bucephala clangula, 4 from Aythya marila and 2 from A. ferina). The isolated parasites were fixed and stored in 70% ethanol and solid preparations were made. Selected external and internal structures of the parasite were measured and photographed using a Zeiss microscope, a microscope camera Opta Tech 2.1 and Opta View 6.0.2.2. It was stated that the sizes of the most important elements of the parasite morphology are generally consistent with those presented in the available literature, nevertheless some differences were observed in both morphology and sizes of some anatomical structures, especially in the form of scolices and hermaphroditic proglottids between specimens isolated from hosts representing three different eco-tribes (Aythyini, Anatini and Mergini).

Cloacotaenia megalops (Nitzsch in Creplin, 1829) (Cestoda, Hymenolepididae) in wild ducks in Western Pomerania, Poland.

Cloacotaenia megalops (Nitzsch in Creplin, 1892) is a polyxenic and cosmopolitan tapeworm from the family Hymenolepididae. Its generic name derives from their typical location (cloaca), and the typical final hosts which are birds typically associated with water and marsh environments: Anseriformes, Galliformes and Gruiformes. In Poland, the presence of C. megalops has been observed so far in 16 species of ducks from the Baltic coast, the Mazurian Lake District, Wielkopolsko-Kujawska Lowland, Mazovian Lowland, and Podlasie Lowland. In Western Pomerania, quantitative structure analyses were only carried out on Anas platyrhynchos, and therefore the aim of this study was the detailed analysis of environmental populations of C. megalops in wild ducks. The examined tapeworms were isolated from the digestive tract of 1005 wild ducks representing 17 species belonging to three different eco-tribes: Anatini (n=225), Aythyini (n=413) and Mergini (n=367), from northwestern Poland. During the Study 187 C. megalops were found in 89 birds (8.8% of examined ducks) belonging to 7 species: Anas crecca (common teal), A. querquedula (garganey), A. platyrhynchos (mallard) (Anatini); Aythyaferina (pochard), A. fuligula (tufted duck), A. marila (greater scaup) (Aythyini) and Bucephala clangula (goldeneye) (Mergini). The results show the differences in the quantitative structure of C. megalops among the examined species of ducks. The highest prevalence was found in mallard (18.6%) and the lowest in greater scaup (3.2%). The highest mean intensity was observed in greater scaup (4.0), and the lowest in garganey and common teal (1.0). Relative density was at a similar level in the tested birds. Based on the ratio of dominance, it was found that C. megalops is a rare species in the cestodofauna in the examined birds.

[First record of Microsomacanthus tuvensis Spasskaya et Spasskii, 1961 (Cestoda, Hymenolepididae) in Poland]. / Microsomacanthus tuvensis Spasskaya et Spasskii, 1961 (Cestoda, Hymenolepididae) po raz pierwszy notowany w Polsce.

During standard parasitological studies of the tufted duck Aythya fuligula, obtained from fishermen from West Pomerania in December 2007, three cestode specimens were found in the jejunum of one male host. They were determinated as Microsomacanthus tuvensis (Spasskaya et Spasskii, 1961) on the basis of the cirrus's and cirrus sac's size and vagina's shape. This is the first record of this species in Poland.

A new modified technique for concentrating intestinal parasites.

The present study evaluated the diagnostic performance of a modification of the formol ethyl acetate concentration technique, with the addition of 25% acetic acid as compared with formol ethyl acetate concentration technique (FEA) and fecal parasite concentrator kit Fresh fecal material, free of ova and parasites, was pooled in a ratio of 1:4 with 10% buffered formalin to prepare a standardized specimen. Sufficient volumes of formalin-fixed suspension of Giardia lamblia cysts, Entamoeba histolytica cysts, Cryptosporidium oocysts; Ascaris lumbricoides ova, Necator americanus, Taenia spp. and Hymenolepis nana were used to seed individually 3-ml portions of the fecal specimen. The 3-ml samples were split in three parts, one processed by FEA, a second part with FPC and the third part by the modified FAEA; six smears from each sediment were examined by light microscopy. FAEA technique gave the clearest sediments and the highest numbers in most of the parasites. FAEA resulted in a higher percenttage of H. nana, Taenia spp., N. americanus, and G. lamblia per one ml of stool compared with FEA method. When compared with FPC, the same results were achieved in addition to E. histolytica.

Prevalence of enteroparasites and genotyping of Giardia lamblia in Peruvian children.

Enteroparasites in children from three marginal urban districts of Trujillo (Peru) were studied to treat these children and to design a prevention and control programme. A total of 845 children were examined. The general prevalence of enteroparasites was of 66.3%, and 45.6% were multiparasitized. The pathogenic enteroparasite prevalence were 23.8% (Giardia lamblia), 4.6% (Iodamoeba buschlii), 2.6% (Cyclospora cayetanensis), 2.2% (Hymenolepis nana), and 2% (Cryptosporidium spp.). G. lamblia was the most frequent parasite both in diarrheic children (28.1%) as well as in nondiarrheic ones (19.5%). The G. lamblia genotypes were molecularly characterized by sequence analysis of the glutamate dehydrogenase (gdh) gene using PCR and RFLP. Sequence analysis revealed both Assemblage A (AI and AII) and Assemblage B (BIV), with the predominance of Assemblage AI. All the samples with Assemblage A were diarrheic but not those with Assemblage B. This is the first study of molecular characterization of G. lamblia in Peruvian children and confirms the importance of asymptomatic patients in the transmission of the giardiosis, especially in places with poor hygiene and sanitation.