The dwarf tapeworm Hymenolepis nana in pet rodents in Slovakia-epidemiological survey and genetic analysis.

Rodents are popular companion animals and are often kept as pets for children. However, they can be reservoirs of a variety of zoonotic pathogens. As little attention is being paid to the possibility of acquiring parasitic infections from pet rodents, the occurrence of Hymenolepis nana in rodents from pet shops and breeding clubs of Slovakia was surveyed, with parallel genetic analyses to type isolates from rodent species. In 2016-2018, pooled faecal samples from 119 boxes with 228 mice, 191 rats, 124 hamsters and 25 Mongolian gerbils were collected from 12 pet shops and 3 breeding clubs in five cities of eastern Slovakia. H. nana eggs were detected in 25 (21.0%) boxes. Animals from pet shops were infected more frequently (24.6% positive boxes) than those from breeding clubs (17.2%), without statistical significance. The highest prevalence was recorded in rats from pet shops, where 41.7% of boxes contained parasite eggs. Hamsters and mice in pet shops were also frequently infected; in 23.8% and 25% of boxes, respectively, H. nana eggs were observed. Prevalence in rats and hamsters from breeding clubs was lower, but in mice surpassed 40%. Nine samples with positive PCR products in any of the four DNA regions, mitochondrial cox1 and nuclear pmy, ITS1 and ITS2 targets, gave profiles characteristic of H. nana. The results imply the risk of zoonotic transmission of hymenolepiasis in Slovakia. Particular attention should be given to hygiene level maintained while keeping rodents. Furthermore, rodents intended for sale should be tested for parasites and then dewormed.

Selected Molecular Mechanisms Involved in the Parasite⁻Host System Hymenolepis diminuta⁻Rattus norvegicus.

The rat tapeworm Hymenolepis diminuta is a parasite of the small intestine of rodents (mainly mice and rats), and accidentally humans. It is classified as a non-invasive tapeworm due to the lack of hooks on the tapeworm's scolex, which could cause mechanical damage to host tissues. However, many studies have shown that metabolites secreted by H. diminuta interfere with the functioning of the host's gastrointestinal tract, causing an increase in salivary secretion, suppression of gastric acid secretion, and an increase in the trypsin activity in the duodenum chyme. Our work presents the biochemical and molecular mechanisms of a parasite-host interaction, including the influence on ion transport and host intestinal microflora, morphology and biochemical parameters of blood, secretion of antioxidant enzymes, expression of Toll-like receptors, mechanisms of immune response, as well as the expression and activity of cyclooxygenases. We emphasize the interrelations between the parasite and the host at the cellular level resulting from the direct impact of the parasite as well as host defense reactions that lead to changes in the host's tissues and organs.

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.

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.

A method for measuring the attachment strength of the cestode Hymenolepis diminuta to the rat intestine.

A unique adaptation of many internal parasites of mammals is their ability to stay in the intestine for extended periods of time and resist the normal peristaltic movements and forces that push and expel material. To better understand parasite adhesion behaviour and replicate their attachment method in medical devices, an experiment was designed and performed using the rat tapeworm, Hymenolepis diminuta. The experiment employed a tensile test machine and a digital scale and was designed to calculate the attachment strength of the scolex to the mucosa through the change of the value of the digital scale during the tensile test. The attachment force of H. diminuta is 0.021 ± 0.011 g. This method could be applied in studies of parasite biomechanics and the results may help medical device researchers to better mimic the unique functional morphology of this species of parasite.

Control of Hymenolepis nana infection as a measure to improve mouse colony welfare.

After cannibalism had appeared in the reproductive units of a white mouse colony, treatment against confirmed Hymenolepis nana, a tapeworm with zoonotic potential, was performed on 67 mice in the reproductive and nursery units. Faecal droppings were evaluated by flotation and sedimentation methods. The sedimentation method revealed a higher number of positive results before, during and after the treatment, but the flotation method yielded some additional positive cases. In the reproductive unit, H. nana eggs were confirmed in 50% of the tested mice by the flotation and in 70% by the sedimentation method. In the nursery units, H. nana eggs were detected in 10.5% of the tested mice by the flotation and in 24.6% by the sedimentation method. A colony of mice was treated against the tapeworm H. nana with praziquantel and emodepside in doses of 2.574 mg praziquantel/100 g body mass and of 0.642 mg emodepside/100 g body mass. The content of the original pipettes (Profender®) was applied as a spot-on on the back of the neck in the area between the shoulders. The application was repeated three times at 14-day intervals. Seven days after the third therapy no H. nana was found in any of the tested mice in the reproductive or the nursery units. After the treatment, cannibalism was no longer observed. This treatment represented one of the steps aimed at improving animal welfare and preventing potential zoonotic disease. The public health significance of this cestode should receive more attention, especially among people who take care of mice, have them as pets, or feed them to reptiles.

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.

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.

The anthelmintic efficacy of natural plant cysteine proteinases against the rat tapeworm Hymenolepis diminuta in vivo.

Hymenolepis diminuta is a natural parasite of the common brown rat Rattus norvegicus, and provides a convenient model system for the assessment of the anthelmintic activity of novel drugs against cestodes. The experiments described in this paper indicate that treatment of rats infected with H. diminuta with a supernatant extract of papaya latex, containing a mixture of four cysteine proteinases, was moderately efficacious, resulting in a significant, but relatively small, reduction in worm burden and biomass. However, faecal egg output was not affected by treatment. In our experiments these effects were only partially dose-dependent, although specific inhibition by E-64 confirmed the role of cysteine proteinases as the active principles in papaya latex affecting worm growth but not statistically reducing worm burden. Data collected for a further 7 days after treatment indicated that the effects of papaya latex supernatant on worm loss and on worm growth were not enhanced. Our findings provide a starting point for further refinement in formulation and delivery, or assessment of alternative natural plant-derived cysteine proteinases in efforts to develop these naturally occurring enzymes into broad-spectrum anthelmintics, with efficacy against cestodes as well as nematodes.

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.

The antioxidant defence mechanisms of parasite and host after chronic Hymenolepis diminuta infestation of the rat.

The aim of the present study was to determine antioxidant defence mechanisms in the rat and Hymenolepis diminuta after long-term infestation. We determined levels of oxidative stress markers, and activity of antioxidant enzymes in the rat small intestine and in particular parts of H. diminuta. Observed changes in antioxidant enzymes activity in H. diminuta and the rat intestine indicate the defence against parasitic infestation and probably allowed parasite to adapt and live in oxidative stress.

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.

Mebendazole in the treatment of Hymenolepis nana infections in the captive ring-tailed lemur (Lemur catta), China.

The present study was conducted to evaluate the effectiveness of mebendazole in the treatment of Hymenolepis nana infection in ring-tailed lemurs (Lemur catta). Ten (L. catta) from the Chengdu Zoological Garden in China, which were naturally infected with H. nana, were treated with mebendazole (10 mg/kg for 5 days). A posttreatment fecal examination was conducted 10 and 20 days after the start of treatment. All treatments resulted in a decrease in the number of eggs per gram in the posttreatment sample compared with the pretreatment sample. Reduction of mean egg count was 97.6% and 100% on days 10 and 20, respectively. The results indicated that mebendazole has marked efficacy against H. nana infections in L. catta.

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 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.

Gene-based molecular characterization of cox1 and pnad5 in Hymenolepis nana isolated from naturally infected mice and rats in Saudi Arabia.

Mice and rats are animals commonly used in research and laboratory testing. Compared with other animal species, they harbor many more zoonotic agents. Hymenolepis nana (H. nana) is a common tapeworm that parasitizes both humans and rodents. Although this tapeworm is of socio-economic importance worldwide, information related to its mitochondrial genome is limited. The present study examined the sequence diversity of two mitochondrial (mt) genes, subunit I of cytochrome oxidase (cox1) and NADH dehydrogenase subunit 5 (pnad5), of H. nana in mice and rats from two geographical regions of Saudi Arabia (Makkah and Riyadh). Partial sequences of cox1 and pnad 5 from individual H. nana isolates were separately amplified using polymerase chain reaction (PCR) and sequenced. The GC contents of the sequences ranged between 31.6-33.5% and 27.2-28.6% for cox1 and pnad5, respectively. The genomic similarity among specimens determined via cox1 primer and pnad5 primer was 97.1% and 99.7%, respectively. Based on these primers, our data did not indicate any differences between H. nana from rat and mice isolates. Results demonstrated that the present species are deeply embedded in the genus Hymenolepis with close relationship to other Hymenolepis species, including H. nana as a putative sister taxon, and that the isolates cannot be categorized as belonging to two different groups with origins in Makkah and Riyadh.

The effect of Nigella sativa oil against Aspiculuris tetraptera and Hymenolepis nana in naturally infected mice.

OBJECTIVE: To investigate the antiparasitic effect of Nigella sativa oil (NSO) on Aspiculuris tetraptera (A. tetraptera) and Hymenolepis nana (H.nana) in mice in January 2005. METHODS: Mice were obtained from the animal house facility of the Faculty of Medicine, Yuzuncu Yil University, Van, Turkey. The natural infections were determined by the cellophane tape method and the centrifugal flotation method of stool samples. The infected mice with A. tetraptera and H.nana were divided into 4 groups; 2 treatment and 2 control groups. Nigella sativa oil was given at the dose of 250 ul/kg body weight orally for 2 consecutive days in the 2 treatment groups. All the mice were sacrificed on the seventh day after the last treatment. Gastrointestinal tract of the sacrificed animals was opened and washed with a serum physiologic. The contents were examined under a stereo microscope for counting and identifying of the parasites. The treatment and the control groups were compared using Mann-Whitney U-Test. RESULTS: Nigella sativa oil reduced both A. tetraptera and its eggs. The difference was significant between Group 1 and Group 3 (p<0.05). Nigella sativa oil reduced H.nana eggs starting from second day of the treatment until necropsy day during 5 days, but it was not significant between Group 2 and Group 4 (p>0.05). CONCLUSION: Antiparasitic effect of NSO is related to its stimulating immune system.

A taxonomic review of hymenolepidids (Eucestoda, Hymenolepididae) from dormice (Rodentia, Gliridae), with descriptions of two new species.

In present study the systematic and taxonomic position of hymenolepidids parasitizing rodents of the family Gliridae from Europe and Central Asia is discussed. Hymenolepis myoxi is redescribed on the basis of the type material from the fat dormouse Glis glis deposited in the collection of the Museum für Naturkunde, Berlin, Germany. Significant corrections of morphologically distinctive characters attributable to H. myoxi include: (1) recognition of a rudimentary rostellar apparatus; (2) absence of rostellar hooks and spination on the suckers; and (3) tissues of the scolex and neck filled with numerous "firm elements". Hymenolepis sulcata was recognised as a synonym of H. myoxi (sensu stricto). The generic allocation of true H. myoxi and validity of the genus Armadolepis is clarified. Specimens from Eliomys quercinus originally designated as H. myoxi by Baer (1932) are described as a new species, Armadolepis jeanbaeri n. sp. The taxonomy has potentially been confused as Spassky (1954) designated misidentified specimens of H. myoxi sensu Baer (1932) as the type species of the genus Armadolepis. In the current article, this error is corrected and A. jeanbaeri n. sp. is fixed as the type of the genus Armadolepis. An additional new species of Armadolepis, A. tenorai n. sp., is described from Dryomys nitedula from Almaty Province, Kazakhstan. The generic diagnosis of Armadolepis is amended. Armadolepis (sensu stricto) is subdivided into two subgenera; the nominotypical subgenus includes species having well developed rostellar apparatus armed by rostellar hooks and A. (Bremserilepis) n. subgen. includes species with rudimentary and unarmed rostellar apparatus.

Occurrence of Hymenolepis diminuta: a potential helminth of zoonotic importance in murid rodents / Ocorrência de Hymenolepis diminuta: um helminto potencial de importância zoonótica em roedores murídeos

The study reveals the prevalence of a potential rodent-borne zoonotic helminth species, Hymenolepis diminuta in commensal rodents caught from irrigated and rain-fed areas of Swat, Pakistan. Three hundred and fifty rodents (269 rats and 81 mice) trapped during vegetative, flowering/fruiting and mature/harvesting stages of crops were studied from 2011-2013. Hymenolepisdiminuta eggs were identified on the basis of their shape, size, colour and markings on the surface of the egg shell and three pairs of embryonic hook-lets. Overall prevalence of H. diminuta was 3.14% (n=11/350). The highest prevalence 3.49% (n=5/143) of H. diminuta was noted at harvesting stages of the crops whereas the lowest 2.59% (n=2/77) during vegetative stage. Infection was higher in males 3.25% (n=7/215) than females 2.96% (n=4/135). Adult rodents were highly infected while no sub-adult was found infected. Infection was higher in mice 3.70% (3/81) than rats 2.69% (8/269) while no significance (p=1.0000:0.1250 to 32.00 CI). Rats and mice appears to show the most suitable reservoirs by hosting H. diminuta a zoonotic helminth. The presence of these rodents in all possible habitats can act as a main channel of transferring parasites through various habitats and can pose a hazard to humans in the area.

O estudo revela a prevalência de uma espécie potencial de helmintos zoonóticos transmitidos por roedores, Hymenolepis diminuta, em roedores comensais capturados em áreas irrigadas e alimentadas pela chuva de Swat, Paquistão. Trezentos e cinquenta roedores (269 ratos e 81 camundongos) presos durante os estágios vegetativo, floração/frutificação e maturidade/colheita das safras foram estudados de 2011-2013. Ovos de Hymenolepisdiminuta foram identificados com base em sua forma, tamanho, cor e marcações na superfície da casca do ovo e três pares de anzóis embrionários. A prevalência geral de H. diminuta foi de 3,14% (n = 11/350). A maior prevalência 3,49% (n = 5/143) de H. diminuta foi observada na fase de colheita das lavouras, enquanto a menor 2,59% (n = 2/77) durante a fase vegetativa. A infecção foi maior nos homens 3,25% (n = 7/215) do que nas mulheres 2,96% (n = 4/135). Roedores adultos foram altamente infectados, enquanto nenhum subadulto foi encontrado infectado. A infecção foi maior em camundongos 3,70% (3/81) do que em ratos 2,69% (8/269), embora sem significância (p = 1,0000: 0,1250 a 32,00 CI). Ratos e camundongos parecem mostrar os reservatórios mais adequados hospedando H. diminuta um helmintos zoonótico. A presença desses roedores em todos os habitats possíveis pode atuar como um canal principal de transferência de parasitas através de vários habitats e pode representar um perigo para os humanos na área.

The chromosomes of Rodentolepis nana (Siebold, 1852) Spasskii, 1954 obtained from naturally infected mice conventionally maintained in a Braziuan laboratory animal house.

The karyotype of Rodentolepis nana obtained from mice in Rio de Janeiro, Brazil, was described. The diploid chromosome number obtained by the division of embryonic cells was 2n = 12. The first and the third pairs presented subterminal centromeres and the other pairs were all acrocentric. The studied species differed in chromosome morphology when compared to previous description by Mutafova and Gergova (1994) in Bulgaria, suggesting an intraspecific variation.