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.

Intestinal helminth and protozoan (parasitic) infections are found mainly in areas with warm, humid climates and in many developing countries. Bolivia currently has high parasite infection rates, including intestinal helminth and protozoan infections. Despite the high prevalence of parasitic infections, nationwide preventive measures for Bolivian children have not yet been implemented. Soil-transmitted helminth infection rates in Japan decreased sharply through practice of health education, mass stool examination and treatment. We investigated the effects of mass stool examination and treatment on parasitic infection rates in Bolivian children. Mass stool examination was performed using the formalin-ether medical sedimentation method between 2013 and 2015, and all infected children were administrated anthelminthic medicine within 2 months post-examination. During the study period, the overall infection rate decreased significantly, but Giardia intestinalis infection rate increased. This may have been related to the interval between treatment and examination. To decrease infection rates for all parasites, the treatment should be performed once or twice a year. Our results suggest that a program of mass stool examination and treatment could effectively reduce the overall parasite-infection rate in Bolivian children.

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.

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.

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.

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).

[First record of Microsomacanthus tuvensis Spasskaya et Spasskii, 1961 (Cestoda, Hymenolepididae) in Poland]

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.

A behavioral study of the beetle Tenebrio molitor infected with cysticercoids of the rat tapeworm Hymenolepis diminuta

The host-parasite relationship, Tenebrio molitor-Hymenolepis diminuta, was analyzed. The learning behavior of infected and uninfected (control) beetles in a T-maze was compared. The infected beetles moved much slower in the T-maze than the controls. The infected beetles reached the same level of learning as the controls. However, they needed more trials than the controls. The effect of the infection was already distinct after the first week and even higher after the second week. This indicates that the initial phase of infection caused stress in the beetles. Longer infection did not worsen their ability to learn. Thus, the parasites clearly changed the behavior of their intermediate host and probably made them more susceptible to their final host, the rat.

Helminth infections in small mammals from Ulu Gombak Forest Reserve and the risk to human health

A survey for small mammal parasites carried out in a secondary forest of Ulu Gombak, Selangor, Peninsula Malaysia yielded the following animals: Rattus bowersi (7), Rattus tiomanicus jalorensis (2), Maxomys rajah (12), Maxoyms whiteheadi (3), Leopoldamys sabanus(13), Sundamys muelleri(10), Lariscus insignis (1), Sundasciurus tenuis (1) and Tupaia glis (2). The following nematodes: Capillaria hepatica, Hepatojarakus malayae, Trichostrongylus sp. and Streptopharagus sp., the following cestodes: Hymenolepis sp., Raillietina sp. and Taenia taeniaformis; and trematode, Zonorchis sp. from Tupaia glis were recovered. No parasites were observed during blood examination. No endoparasite was seen in Maxomys whiteheadi, Lariscus insignis and Sundasciurus tenuis. The following parasites, Capillaria hepatica, Hymenolepis sp., Raillietina sp. and Taenia taeniaformis are considered of medical importance.

[Cestode of the family Hymenolepididae from ducks of Chukotka: Microsomacanthus parasobolevi sp. n.--a widely distributed parasite of eider ducks]

A new species of the genus Microsomacanthus Lopez-Neyra, 1942 is described. The material was collected from eider ducks (Somateria mollissima, S. fischeri, and S. spectabilis) in the Chaunskaya lowland (North-Western Chukotka). Microsomacanthus parasobolevi sp. n. differs from the closest species of this genus (M. polystictae Regel, 1988, M. sobolevi Spassky et Jurpalova, 1964; M. strictophalius Tolkatchieva, 1966) by the structure and size of the copulatory organ. Wide distribution of the new species was detected based on the cestodes collections from eider ducks of the Eastern Chukotka, Lena River mouth (in the museum of the Institute of the Parasitology RAS) and Iceland (Karl Skirnisson's cestode collection of the common eider). Furthermore, this species was reported once of the common eider in Newfoundland and Labrador, but erroneously identified as Hymenglejns (Microsomacanthnis) formosoides Spasskaja et Spassky, 1961 by Bishop and Threlfall (1974).

[Cestode infections in Poland in 2003]

In 2003, 218 intestinal cestode infections were registered in Poland. Among them 157 were caused by Taenia saginata, 4 by T. solium, 32 by Taenia sp., 1 by Diphyllobothrium latum,. Moreover, 34 cases of cystic echinococcosis were also registered. The obtained results confirmed decreasing frequency of intestinal cestodes in Poland.

The Hymenolepis diminuta–Golden Hamster (Mesocricetus auratus) Model for the Evaluation of Gastrointestinal Anticestode Activity

A novel laboratory anticestode assay was developed using Hymenolepis diminuta in the hamster. The commercial anticestode compounds, praziquantel, bunamidine, and niclosamide were active against patent infections of Hymenolepis diminuta in golden hamsters (Mesocricetus auratus) when given orally at 3.125, 100, and 200 mg/kg, respectively. The gastrointestinal nematode anthelmintics, cambendazole and mebendazole, were active at 50 mg/kg. Rafoxanide (fasciolicide) was active at 25 mg/kg, the lowest level tested. The coccidiostat, nicarbazin, was active at experimental levels (800 mg/kg and up). The anthelmintic-ectoparasiticide (endectocide), ivermectin, was inactive against the tapeworm at 0.5 mg/kg, as expected.

[Cestode infections in Poland in 2002]

In 2002, 264 intestinal cestode infections were registered in Poland. Among them 193 were caused by Taenia saginata, 3 by T. solium, 53 by Taenia sp., 1 by Hymenolepis nana, 1 by Diphyllobothrium latum, 1 by Hymenolepis diminuta. Moreover, 40 cases of cystic echinococcosis were also registered. The obtained results confirmed decreasing frequency of intestinal cestodoses in Poland.

[Cestode infections in Poland in 2001]

In 2001, 286 intestinal cestode infections were registered in Poland. Among them 195 were caused by Taenia saginata, 2 by T. solium, 71 by Taenia sp., 1 by Hymenolepis diminuta, and 1 by Dipylidium caninum. Moreover, 37 cases of echinococcosis were also registered. The obtained results confirmed the low frequency of intestinal cestodoses in Poland.

[Hymenolepiasis preventing measures in the population of Ivanovo-Frankovsk]

The authors review of researches into the influence of socioeconomic factors of development of the town (migration, urbanization, etc.) on the formation or reduction of hymenolepidosis foci. Emphasis is laid on various influences of the above factors on the distribution of hymenolepidiasis. The importance of helminthic control is well underlined. Annual medical examination of the whole population is considered to be the main prophylactic measure introduced into computer educational programs. The problems to be immediately solved by health administrators are outlined.

Detection of the rodent tapeworm Rodentolepis (=Hymenolepis) microstoma in humans. A new zoonosis?

A longitudinal survey of gastro-intestinal parasites was conducted over a 3-year period in remote communities in the north-west of Western Australia where, based on diagnosis by microscopy of faecal samples, Rodentolepis (=Hymenolepis) nana was found to be the most common enteric parasite. In the present study, using molecular tools, we describe the unexpected discovery, of a mixed infection with a second hymenolepidid species, Rodentolepis (=Hymenolepis) microstoma in four of the surveyed individuals. In the absence of any reliable earlier reports we believe this is to be the first instance of the detection of R. microstoma from human hosts. The development of a diagnostic restriction fragment polymorphism has enabled the study of R. microstoma in human populations and will greatly facilitate a more thorough understanding of the epidemiology of this parasite in the future.

Demographic and parasitic infection status of schoolchildren and sanitary conditions of schools in Sanliurfa, Turkey

BACKGROUND

The design and development of school health programmes will require information at demographic characteristics of schoolchildren and the major health burdens of the school-age group, the opportunities for intervention and the appropriateness of the available infrastructure. This study aims to analyse demographic and parasitic infections status of schoolchildren and sanitary conditions of schools in Sanliurfa province of south-eastern Turkey.

METHOD

Three primary schools were randomly selected in the shantytown, apartment and rural districts. A total of 1820 schoolchildren between 7-14 years age were took part to the survey of whom 1120 (61.5%) were boys and 700 (38.4%) were girls. A child form (including child's name, sex, age, school grade and parasitic infections) and school survey form (including condition of water supply, condition of latrines, presence of soaps on the basins and presence of garbage piles around to the schools) were used for demographic, parasitic and sanitary surveys. Stool samples were examined by cellophane thick smear technique for the eggs of intestinal helminths.

RESULTS

The demographic survey showed that number of schoolchildren was gradually decreased as their age's increase in shantytown school. The sex ratio was proportional until the second grade, after which the number of females gradually decreased in children in shantytown and rural schools while, in apartment area, schoolchildren was proportionally distributed between age groups and gender even the high-grade students. The prevalence of helminthic infections was %77.1 of the schoolchildren in shantytown, 53.2% in apartment district and 53.1% of rural area. Ascaris lumbricoides was the most prevalent species and followed by Trichuris trichiura, Hymenolepis nana and Taenia species in three schools. Sanitation survey indicated that the tap water was limited in shantytown school, toilet's sanitation was poor, available no soaps on lavatories and garbage piles were accumulated around the schools in shantytown and rural area, while, the school in apartment area was well sanitised.

CONCLUSIONS

These results indicated that burden of parasitic infections and poor sanitation conditions constituted public health importance among to the shantytown schoolchildren. School health programmes including deworming and sanitation activities through the health education and improvement of sanitation conditions in the schools have a potential to better health and education for schoolchildren. These programmes also offer the potential to reach significant numbers of population in the shantytown schools with high level of absenteeism.

Hymenolepis diminuta infection in a child living in the urban area of Rome, Italy

We report a case of Hymenolepis diminuta infection in an Italian child affected by tuberous sclerosis. Praziquantel is the drug of choice for the treatment of H. diminuta infection. However, considering the patient's neurological disease, we decided to use not praziquantel but niclosamide, which proved equally effective.

Hymenolepis pseudodiminuta Tenora et al. 1994 from Apodemus speciosus and H. diminuta: a comparison of experimental infections in rats

The successful maintenance of Hymenolepis pseudodiminuta, isolated from Apodemus speciosus, is described for the first time. In the laboratory, the flour beetle, Tribolium confusum, and F344 rats could serve as intermediate and definitive hosts, respectively. In single worm infections with H. pseudodiminuta, which were carried in two groups of rats, adult worms were recovered from eight and seven out of ten rats, respectively, while Hymenolepis diminuta was found in all of ten rats 6 weeks after inoculation. The worm weight of H. pseudodiminuta in rats was significantly lower than that of H. diminuta. The egg output of H. pseudodiminuta occurred significantly earlier than that of H. diminuta. The number of eggs in the faeces of H. diminuta-infected rats was approximately twofold higher than the number in the faeces of H. pseudodiminuta-infected rats throughout the course of the infection. Mucosal mast cells in rats infected with H. pseudodiminuta were significantly more common than in rats infected with H. diminuta. No detectable IgE antibodies were found in the uninfected and H. diminuta-infected rat groups; however total IgE was detected in H. pseudodiminuta-infected rats but the concentrations were variable between individuals.

Seroprevalence of anti-cysticercus antibodies among the children living in the urban environs of Maputo, Mozambique

Blood and faecal samples were collected from 269 children (aged 0-15 years) who lived in the urban environs of Maputo, the capital city of Mozambique. Antibodies against Cysticercus cellulosae were detected, at a titre of at least 1:100, in 56 (20.8%) of the blood samples. When the stool samples were checked for Taenia solium and other helminths, both as direct smears and after formalin-ether concentration, 180 (67.0%) were found to contain at least one helminth species. The parasites most commonly detected in the faecal samples were Trichurus trichiura (36.0%) and Ascaris lumbricoides (35.7%). Only in one sample (0.4%) were gravid proglottids of Ta. solium detected, but Hymenolepis nana (1.1%) and H. diminuta (0.4%) were also found. A positive correlation between seropositivity for anti-cysticercus antibodies and subject age, and positive associations between such seropositivity and infection with A. lumbricoides and infection with Tr. trichiura were observed. None of the other demographic and environmental factors investigated--the child's sex, religion and access to toilets and/or piped water, the type of house in which he or she lived, the number of individuals in the household to which he or she belonged, and whether that household had pets or raised livestock--showed any apparent association with either the seroprevalence of anti-cysticercus antibodies or infection with any intestinal helminth. The use of water from the common sewage-drainage system for agricultural irrigation in the study area probably causes most of the contamination with intestinal parasites.

[Cestode infections in Poland in 2000]

In 2000, 439 intestinal cestode infections were registered in Poland. Among them 359 were caused by Taenia saginata, three by T. solium, 52 by Taenia sp., two by Hymenolepis nana, two by Diphyllobothrium latum, and one by Dipylidium caninum. Moreover, 29 cases of echinococcosis were also registered. The obtained results confirmed the low frequency of intestinal cestodoses in Poland.

A molecular phylogeny of nuclear and mitochondrial sequences in Hymenolepis nana (Cestoda) supports the existence of a cryptic species

Since isolates of Hymenolepis nana infecting humans and rodents are morphologically indistinguishable, the only way they can be reliably identified is by comparing the parasite in each host using molecular tools. In the current study, isolates of H. nana from rodent and human hosts from a broad geographical range were sequenced at the ribosomal first internal transcribed spacer (ITS1), the mitochondrial cytochrome c oxidase subunit 1 (C01) gene and the nuclear paramyosin gene loci. Twenty-three isolates of H. nana were sequenced at the ITS1 locus and this confirmed the existence of spacers which, although similar in length (approximately 646 bp), differed in their primary sequences which led to the separation of the isolates into 2 clusters when analysed phylogenetically. This sequence variation was not, however, related to the host of origin of the isolate, thus was not a marker of genetic distinction between H. nana from rodents and humans. Sequencing of a 444 bp fragment of the mitochondrial cytochrome c oxidase 1 gene (C01) in 9 isolates of H. nana from rodents and 6 from humans identified a phylogenetically supported genetic divergence of approximately 5% between some mouse and human isolates. This suggests that H. nana is a species complex, or 'cryptic' species (=morphologically identical yet genetically distinct). A small segment of the nuclear gene, paramyosin, (625 bp or 840 bp) was sequenced in 4 mouse and 3 human isolates of H. nana. However, this gene did not provide the level of heterogeneity required to distinguish between isolates from rodent and human hosts. From the results obtained from faster evolving genes, and the epidemiological evidence, we believe that the life-cycle of H. nana that exists in the north-west of Western Australia is likely to involve mainly 'human to human' transmission.

Hymenolepis nana: a common cause of paediatric diarrhoea in urban slum dwellers in India

The prevalence of intestinal parasitic infections was studied for a period of 5 years (April 1996-April 2001) among urban slum dwellers. All age groups were represented in the study. Parasitological examinations were performed on 939 faecal specimens collected on a household basis. The total prevalence of pathogenic parasites was 33.6 per cent. No significant age and sex differences in pathogenic parasites were observed. The prevalence of intestinal helminths and pathogenic protozoa was as follows: Hymenolepis nana (9.9 per cent), Ascaris lumbricoides (8.5 per cent), Giardia lamblia (8.4 per cent) and Entamoeba histolyticaldispar (3.7 per cent). Thirty-four E. histolytica/dispar positive samples were cultured and speciation was done using polymerase chain reaction (PCR). The predominant isolate was E. dispar compared to E. histolytica. The notable finding of the present study was high prevalence of Hymenolepis nana compared with other parasitic infections in slum dwellers.

Comparative clinical studies of nitazoxanide, albendazole and praziquantel in the treatment of ascariasis, trichuriasis and hymenolepiasis in children from Peru

Three randomized clinical studies were conducted in 2000 to evaluate the efficacy of nitazoxanide paediatric suspension compared to albendazole in the treatment of ascariasis and trichuriasis and praziquantel in the treatment of hymenolepiasis in children from Cajamarca, Peru. Nitazoxanide was administered at a dose of 100 mg (age 1-3 years) or 200 mg (age 4-11 years) twice daily for 3 days, albendazole as a 400-mg single dose and praziquantel as a 25-mg/kg single dose. Post-treatment parasitological examinations were carried out on 3 faecal samples, each collected on a different day between 21 and 30 days following initiation of treatment. Nitazoxanide cured 89% (25/28), 89% (16/18) and 82% (32/39) of the cases of ascariasis, trichuriasis and hymenolepiasis respectively compared with 91% (32/35), 58% (11/19) and 96% (47/49) for the comparator drugs. Each of the drugs produced egg reduction rates in excess of 98%. There were no significant adverse events or abnormalities in haematology or clinical chemistry values or urinalysis.

Tapeworm identification in the fat sand rat (Psammomys obesus obesus)

The identification of a tapeworm (Rodentolepis nana, formerly named Hymenolepis nana) infection in a research breeding colony of sand rats (Psammomys obesus obesus) was complicated because of the unexpected long length (< 150 mm) of the worms. Other morphologic features that were consistent with this identification included the number (24), size (16 mm), and shape of the hooks on the rostellum. No evidence of intermediate hosts was found in the colony. Previous surveys of natural populations of sand rats had not identified this tapeworm. However, a detailed search of the literature revealed that variation in the size of R. nana had been reported, thus supporting the final identification of the tapeworm. R. nana is important and interesting because of its zoonotic potential and because it is the only tapeworm that is able to infect its definitive host without use of an intermediate host. This report is presented to help clarify the ambiguity found in the laboratory animal literature about the differences in the size of R. nana among rodent species used in research.

Morphological and genetic differentiation of Rodentolepis straminea (Goeze, 1752) and Rodentolepis microstoma (Dujardin, 1845) (Hymenolepididae)

The two related species, Rodentolepis straminea (Goeze, 1782) and Rodentolepis microstoma (Dujardin, 1845) (Cestoda, Hymenolepididae), both parasites of rodents, were compared morphologically and electrophoretically. Adult worms were isolated from three wild rodent species of the family Muridae (Apodemus flavicollis, Apodemus sylvaticus, and Mus musculus) from three different sites in Spain and France. Although these two species were strikingly similar in morphological appearance, some of the morphological and metrical features analysed (scolex, mature segments and eggs) can be used for differentiation. Fixed allelic differences were found. Of the ten enzymes detected by starch-gel electrophoresis, six (AAT, AK, GPI, MDH, NP, PGM) showed characteristic isoenzyme profiles in each species. Only in MPI, PEPC, PEPD, and ME enzyme loci were no differences found. The study revealed that the two taxa can be clearly differentiated.

Human infection with Hymenolepis diminuta: case report from Spain

We report a case of Hymenolepis diminuta infection in a human. The patient was a 5-year-old girl referred to us through the onset of a cyanotic attack. Treatment with a single dose (10 mg/kg of body weight) of praziquantel was ineffective, but the parasite was eradicated after three treatment cycles with the same drug at dosages of 25 mg/kg/day for 5 days.

The spatial and temporal concentrations of choline in the lumen contents of the small intestine of uninfected and Hymenolepis diminuta infected rats

The spatial and temporal concentrations of free choline in the lumen of the small intestine of the uninfected and Hymenolepis diminuta-infected rat were investigated. In the unfed infected or uninfected rat, the choline concentrations ranged from approximately 500 microM in the duodenum to approximately 20 microM in the posterior ileum, with some segments in infected rats containing significantly higher choline levels than in uninfected rats. Following feeding, choline levels were significantly elevated to approximately 3 mM by 6 h, although these concentrations fell rapidly in transit down the intestine. By 12 h the choline levels were similar to those in the unfed rat. An initial small shift in the worm biomass toward the duodenum after feeding was followed by a redistribution of biomass along the length of the small intestine. The worm biomass, however, had little or no effect on the choline levels. The high concentrations of free choline observed in the anterior regions of the intestine are postulated to be predominantly determined by nutritional intake while the concentrations in the posterior region may in part be determined by blood choline levels. The high levels of choline indicate that choline is not limiting to support the growth of the worms.

[The effect of treatment on the course of invasion by Hymenolepis nana and the state of its population in white mice]

Leukinferon administered before infection affects the development of a Hymenolepis nana population in the murine intestine: in rodents, its defective forms predominate over mature ones. Leukinferon caused cell prestimulation in the immune system and activation of nonspecific defense factors. The cytokine properties of the agent appear to have an impact on parasitic growth and development by leading to formation of defective Hymenolepis forms directly and indirectly through the host's body due to the prestimulation and enhancement of nonspecific defense. There may be a concurrent influence of these factors on H. nana embryos in the murine intestine.

Application of lactophenol cotton blue for identification and preservation of intestinal parasites in faecal wet mounts

Wet mounting is the simplest and easiest technique for the examination of faeces. Routinely employed wet mounts in most of the laboratories include saline, iodine and buffered methylene blue. Lactophenol cotton blue [LCB] staining--mounting medium is commonly used for microscopic identification of fungi. LCB and its modifications were tested as staining mounting medium on parasite positive faecal samples [both fresh as well as formalin fixed] to stain and demonstrate morphology and to preserve parasitic elements [trophozoites, cysts, ova and larvae] in wet mounts. Protozoal cysts [Entamoeba histolytica and Giardia lamblia], helminthic OVA [Ancylostoma duodenale, Ascaris lumbricoides, Enterobius vermicularis, Taenia solium and Hymenolepis nana] and larvae [Strongyloides stercoralis] were well-stained and preserved their morphology in nailpolish enamel sealed LCB-faecal mounts. Morphology was better appreciated in LCB-formalin fixed faecal mounts as compared to LCB fresh faecal mounts and was well preserved by the end of twelve weeks.

[Epidemiological study on Hymenolepis nana infection in Ciego de Avila Province, Cuba]

An epidemiological study on H. nana infection was carried out in Ciego de Avila province, Cuba, from 1981 to 1995. In this 15 years period 3,108,422 stool samples were examined for parasites, H. nana eggs were found in 250 (0.008%). Seasonal influence of this parasitism was not detected. There were more cases in children than in adults, with males prevailing over females. The more frequent symptoms and signs were abdominal pain, diarrhea and anorexia which relationships with food habits, dwelling characteristics, children day care center and school orchards are analyzed.

Prevalence of intestinal parasites in rural Southern Indians

OBJECTIVE

To determine the prevalence of intestinal protozoal and helminthic infection in a rural population.

METHOD

Seventy-eight members of 15 families from a village were studied. Stool samples from all subjects were examined on alternate days for one month.

RESULTS

The overall prevalence rate of various parasitic infections was 97.4%, with only 2 of 78 subjects not excreting parasites in any of their 15 samples. Eighteen (23.1%) persons had only one type of parasite, while 58 (74.3%) excreted multiple parasites. Giardia and Cryptosporidium were the commonest protozoan infections, affecting 42/78 (53.8%) and 31/78 (39.7%), respectively. Hookworm infestations were the commonest helminthic infections, seen in 48/78 (61.5%). Based on excretion patterns, the asymptomatic individuals could be divided into 2 groups of infrequent and frequent excretors, indicating that the host response may determine the level of parasite replication in the gut.

[Helminth fauna of the red fox (Vulpes vulpes LINNE 1758) in south Sachsen-Anhalt--1: Cestodes]

Between January 1993 and November 1994 a total of 1300 red foxes from the administrative districts Halle and Dessau were examined for the presence of Echinococcus multilocularis and other cestodes. Echinococcus multilocularis-infections were detected in only 4 of 1300 (0.3%) foxes. Furthermore the following cestodes were found: Mesocestoides spp. (54.1%), Taenia crassiceps (17.7%), Taenia polyacantha (11.9%), Hydatigera taeniaeformis (0.2%), Taenia serialis (0.15%), Taenia pisiformis (0.15%), not determinable taeniids (9.2%), Dipylidium caninum (0.2%) and Hymenolepis spp. (0.08%).

Interactions between rat C-reactive protein and adult Hymenolepis diminuta

Interactions between adult Hymenolepis diminuta and rat C-reactive protein (CRP) were investigated in vivo and in vitro. Using an ELISA technique, serum levels of CRP were monitored in rats infected with 100 cysticercoids. Although infection increased the level of this protein in the early stages of parasitization, the increase was not significant until 35 days post-infection (p.i.). Secondary infections did not enhance the response. When H. diminuta was cultured in the presence of CRP, reduced worm motility and opaque areas were observed and electron microscopical studies revealed shedding of microtriches and lysis of the tegument. Initially, damage was restricted to the strobila which correlated with the regional distribution of phosphorylcholine as visualized using immunofluorescence.

Cytokine production during infection with Hymenolepis diminuta in BALB/c mice

Levels of the cytokines IFN-gamma, IL-2, IL-3, IL-4 and IL-5 were monitored in cells from the mesenteric lymph nodes (MLN) of BALB/c mice infected with Hymenolepis diminuta after stimulation in vitro with Con-A. Infection was associated with an increased production of IL-3, IL-4 and IL-5 and a low production of IFN-gamma, indicating the preferential activation of a Th2 response. It is suggested that this reflects the purely lumenal development of this worm. The results are discussed in relation to effector mechanisms known to be involved in immunity to intestinal helminths.

Detection of gastrointestinal nematodes by a coproantigen capture ELISA

An assay is described for the quantitative detection of excretory/secretory antigens liberated by the intestinal nematode Heligmosomoides polygyrus and voided in the host's faeces. A rabbit polyclonal antiserum to the antigens detected them in a dose-dependent manner and was sufficiently sensitive to recognise infection in mice carrying a mean worm burden of nine worms. The assay was specific, giving higher optical density readings with the faeces of mice infected with H polygyrus than with faeces from mice carrying patent infections with Trichuris muris, Hymenolepsis microstoma or the intestinal phase of Trichinella spiralis, or with faeces from rats carrying Hymenolepis diminuta or hamsters carrying Necator americanus or Ancylostoma ceylanicum. It detected the parasite antigens in faeces stored for eight weeks at -20, 4 or 20 degrees C and could detect prepatent infections. The assay has potential for the development of infection intensity-sensitive assays for gastrointestinal nematodes and for the detection of animals harbouring the arrested larvae of parasites.

The minimum effective dose of praziquantel in treatment of Hymenolepis diminuta in rats

To determine the minimum effective dose of praziquantel against Hymenolepis diminuta in rats, 5.0 mg/kg, 2.5 mg/kg, 1.0 mg/kg, 0.5 mg/kg, 0.1 mg/kg, or 0.05 mg/kg praziquantel were given to each of five experimentally infected rats in six groups. Faecal samples from each rat were examined on ten consecutive days following treatment. The rats were killed and examined for worms on day 10. Based on the results of faecal examination and autopsy, the minimum effective dose of praziquantel against Hymenolepis diminuta in rats was determined to be 0.5 mg/kg.

The morphology of hymenolepidid and dilepidid cestodes from common and pygmy shrews (Soricidae) in southeast England

One hundred and six of 109 common shrews (Sorex araneus) and 62 of 72 pygmy shrews (S. minutus), obtained by Longworth trapping in Southeast England, were infected with cestodes. Ten species were recovered: Choanotaenia hepatica and Hymenolepis prolifer (found in S. araneus); Choanotaenia crassiscolex, Hymenolepis furcata, H. jacutensis, H. schaldybini, H. scutigera, H. singularis, H. diaphana and H. infirma (in both hosts). The morphology, taxonomy and ecology of these species are discussed and the findings of the present study are discussed with reference to previous studies of the helminth fauna of British shrews. Cysticercoids of C. crassiscolex were found in the snail, Vitrina pellucida, and cysticercoids of H. schaldybini in the staphylinid beetle, Anthobium unicolor.

[A coprological study of intestinal infections in Northern Morocco (provinces of Tangier, Tetuán and Larache)]

BACKGROUND

An epidemiological study on intestinal parasites has been carried out in Northern Morocco (province of Tangier, Tetuan and Larache). A comparative Study has been made at a provincial, city and areas (urban and rural) level. Also the SPI (simple parasitism index) and the CPI (comparative parasitism index) distribution.

METHODS

The coprological method used were: direct, concentration (Fulleborn, Telemann and Kato) method and ye test technics (Ferric Hematoxylin and E. Chlorazol Black).

RESULTS

The number of faecal samples were 4643, parasitism people 2637 and the total number of parasites were 4816. SPI 56.79% and CPI 1.83. Among the Protozoa, Entamoeba coli, followed by Endolimax nana, Giardia lamblia and Iodamoeba buetschlii prevailed, the other species coming a lung distance behind. Among the Helminths, Trichuris trichiura prevailed much more than the others; Ascaris lumbricoides followed and on the third place were Enterobius vermicularis and Hymenolepis nana. The percentage found for E. vermicularis was very high, since an appropriate technique of diagnosis was not used. The data have been statistically tested.

CONCLUSIONS

We found a high rate of parasitism in the 3 provinces that have studied and an approximate number of two parasites per person. SPI and CPI are greater in Tetuan and Larache than in Tangier.

Specific cross-immunity between Hymenolepis nana and H. diminuta: effects of transfer of immunity with homologous and heterologous immune mesenteric lymph node cells in BALB/c mice

In BALB/c mice, Hymenolepis nana and H. diminuta stimulate a strong response. Accelerated expulsion of adult worms, as well as protection against larvae, occurred anamnestically when homologous or heterologous mesenteric lymph node cells from immune mice were transferred before challenge. The results further support the hypothesis that worm expulsion is a thymus dependent phenomenon. The extensive cross reactivity found is discussed in relation to the distinctive characteristics of the two worms. These results strongly suggest that there are antigenic similarities between the two parasites and that the accelerated expulsion of heterologous challenge infections is the result of a specific response to shared antigens.