Helminth communities from two urban rat populations in Kuala Lumpur, Malaysia

Pterygodermatites (Mesopectines) whartoni (Nematoda: Rictulariidae) encysted larvae in invasive Cuban treefrogs (Osteopilus septentrionalis) from Florida, United States

Species of Pterygodermatites are spirurid nematodes that have expanded their geographic distribution worldwide. They infect a variety of mammalian definitive hosts with few reports of potential paratenic infections in amphibian and reptile hosts. In this study, we report Pterygodermatites sp. larvae identified in free-ranging, invasive Cuban treefrogs (Osteopilus septentrionalis), from central Florida, United States. Encysted larvae were recovered from the skeletal muscle and/or the coelomic cavity of three frogs; molecular characterization of the small subunit (18S) ribosomal RNA and cytochrome oxidase I genes of the parasites matched reported sequences of Pterygodermatites (Mesopectines) whartoni (Tubangui, 1931). This is a parasite native to Southeastern Asia and to the best of the authors' knowledge, it is the first report of the species in the New World. The recovery of invasive Pterygodermatites from invasive Cuban treefrogs in North America highlights the growing concern regarding the potential impact non-native parasites and invasive species may have on native wildlife populations.

Rats and their helminth parasites: Potential zoonosis threats of land use change in the northeastern sub-watersheds of Mount Makiling, Laguna, Philippines

The continuous challenges of land use change have brought potential threats to biodiversity and the spread of zoonotic diseases. In this study, synanthropic rodents and their helminth parasites were used as sentinels to assess the potential impact of land use on zoonosis. Rats were collected in different ecosystems, namely agricultural, agroforest, and residential areas in the northeastern sub-watersheds of Mount Makiling, Laguna, Philippines. Three (3) species of rats were captured, namely, Rattus tanezumi, Rattus norvegicus, and Rattus exulans. Of the total 180 rats collected, 92.7 % were found infected with helminth parasites, namely Hymenolepis diminuta, Hymenolepis nana, Taenia pisiformis, and Strobilocercus fasciolaris (cestodes); Angiostrongylus cantonensis, Nippostrongylus brasiliensis, Strongyloides ratti, Capillaria hepatica, Trichuris muris, and Rictularia sp. (nematodes); and Echinostoma ilocanum (trematode). Of these 11 species, nine (9) were considered zoonotic. This study provides important information on the helminth parasites of rats in the northeastern sub-watersheds of Mount Makiling and the potential threat of zoonotic transmission due to increasing land use change and urbanization in the area. Moreover, urbanization can provide favorable eco-epidemiological conditions for rodent-borne pathogens, such as parasites, that are seriously threatening agricultural settings and human settlements in these areas.

Macro-parasites and micro-parasites co-exist in rodent communities but are associated with different community-level parameters

Wildlife species are often heavily parasitized by multiple infections simultaneously. Yet research on sylvatic transmission cycles, tend to focus on host interactions with a single parasite and neglects the influence of co-infections by other pathogens and parasites. Co-infections between macro-parasites and micro-parasites can alter mechanisms that regulate pathogenesis and are important for understanding disease emergence and dynamics. Wildlife rodent hosts in the Lyme disease system are infected with macro-parasites (i.e., ticks and helminths) and micro-parasites (i.e., Borrelia spp.), however, there has not been a study that investigates the interaction of all three parasites (i.e., I. pacificus, Borrelia spp., and helminths) and how these co-infections impact prevalence of micro-parasites. We live-trapped rodents in ten sites in northern California to collect feces, blood, ear tissue, and attached ticks. These samples were used to test for infection status of Borrelia species (i.e., micro-parasite), and describe the burden of ticks and helminths (i.e., macro-parasites). We found that some rodent hosts were co-infected with all three parasites, however, the burden or presence of concurrent macro-parasites were not associated with Borrelia infections. For macro-parasites, we found that tick burdens were positively associated with rodent Shannon diversity while negatively associated with predator diversity, whereas helminth burdens were not significantly associated with any host community metric. Ticks and tick-borne pathogens are associated with rodent host diversity, predator diversity, and abiotic factors. However, it is still unknown what factors helminths are associated with on the community level. Understanding the mechanisms that influence co-infections of multiple types of parasites within and across hosts is an increasingly critical component of characterizing zoonotic disease transmission and maintenance.

Detection of zoonotic-borne parasites in Rattus spp. in Klang Valley, Malaysia

Background and Aim:

Rattus spp. are the most common animals capable of adapting to their environment. They can be reservoirs or vectors of diseases that facilitate the transmission of zoonotic-borne parasites to humans. Hence, a study on the detection of parasites in rat populations in urban areas is crucial to prepare for emerging zoonosis. Therefore, this study aims to identify blood parasites, ectoparasites, and helminths in Rattus spp. from wet markets located in Klang Valley, an urban area with a high-density human population.

Materials and Methods:

A total of 32 rats were trapped in several wet markets in Klang Valley, Malaysia. They were anesthetized for morphometric examination followed by exsanguination. Various parasitological techniques such as perianal tape test, simple flotation, direct examination of the intestine, and fecal smear were performed for intestinal parasite detection; hair plucking, skin scraping, and full body combing for ectoparasite identification; and blood smear, microhematocrit centrifugation, and buffy coat techniques for blood parasite detection.

Results:

The rats were identified as Rattus rattus (71.9%) and Rattus norvegicus (28.1%). The only blood protozoan found was Trypanosoma lewisi. The ectoparasites identified belonged to two broad groups, mites (Laelaps spp. and Ornithonyssus spp.) and fleas (Xenopsylla cheopis), known to be parasitic zoonotic disease vectors. The zoonotic intestinal parasites were cestodes (Hymenolepis nana), nematodes (Nippostrongylus brasiliensis, Strongyloides spp., Trichuris spp., Capillaria spp., and Syphacia spp.), and intestinal protozoa (coccidian oocysts and Giardia spp.). Microscopic images showing Giardia spp. are the first report of this organism in rats in Malaysia.

Conclusion:

Rats caught in this urban area of the Klang Valley harbor parasites can pose a potential zoonotic threat to humans, raising public health concerns because of their proximity to densely populated urban areas.

Comparative Comprehensive Analysis on Natural Infections of Hymenolepis Diminuta and Hymenolepis Nana in Commensal Rodents

This first comprehensive report from Punjab province of India relates to patho-physiological alterations alongwith morpho-molecular characterisation and risk assessment of natural infections of Hymenolepis diminuta and Hymenolepis nana in 291commensal rodents including house rat, Rattus rattus (n=201) and lesser bandicoot rat, Bandicota bangalensis (n=90). Small intestine of 53.61 and 64.95 % rats was found infected with H. diminuta and H. nana, respectively with a concurrent infection rate of 50.86 %. There was no association between male and female rats and H. diminuta and H. nana infections (ᵡ² = 0.016 and 0.08, respectively, d.f.= 1, P>0.05), while the host age had significant effect on prevalence of H. diminuta and H. nana (ᵡ² = 28.12 and 7.18, respectively, d.f.= 1, P≤0.05) infection. Examination of faecal samples and intestinal contents revealed globular shaped eggs of H. diminuta without polar filaments (76.50 ± 3.01μm x 67.62 ± 2.42 μm), while smaller sized oval eggs of H. nana were with 4 – 8 polar filaments (47.87 ± 1.95 μm x 36.12 ± 3.05 μm). Cestode infection caused enteritis, sloughing of intestinal mucosa, necrosis of villi and inflammatory reaction with infiltration of mononuclear cells in the mucosa and submucosa. Morphometric identification of the adult cestodes recovered from the intestinal lumen was confirmed by molecular characterisation based on nuclear ITS-2 loci which showed a single band of 269 bp and 242 bp for H. diminuta and H. nana, respectively. Pairwise alignment of the ITS-2 regions showed 99.46 % similarity with sequences of H. diminuta from USA and 100 % similarity with sequences of H. nana from Slovakia, Kosice.

Predictors of parasite and pathogen infections in urban rodents of central Argentina

Urban rodents are associated with parasites and pathogens, which present health risks for humans, but information on factors related to parasite and pathogen infection in rodents in cities of Latin America is scarce. This study analyzes the hosts, host community structure and environmental characteristics of parasite and pathogen fauna present in the three species of urban rodents in an urban area of South America. Rodents were captured seasonally in seven different neighborhoods. Digestive tracts were dissected under stereoscopic microscopy and feces were processed using a sedimentation technique. Protozoa and bacteria were detected through polymerase chain reaction and indirect immunofluorescence techniques. In Rattus norvegicus, Rattus rattus and Mus musculus, ten helminths, three protozoa and two bacteria were found. Six were zoonotic: Toxoplasma gondii; Hymenolepis diminuta; Rodentolepis nana; Strobilocercus fasciolaris; Leptospira borgpetersenii; and Leptospira interrogans. The parasite and pathogen infections were influenced by the host species, the host community structure, the season, and the presence of streams in the neighborhood. Urban rodents may be the infection source of many zoonotic diseases and it is important to generate public policies for this problem. This study is one example of the situation of many cities of Latin America, where peripheral neighborhoods are growing dramatically.

Occurrence and Prevalence of Macroparasites of African Giant Rats (Cricetomys Gambianus) in a Savanna Region of Nigeria

Rodents play an important role in the transmission of zoonotic diseases since they serve as reservoirs of these infections. A survey of ecto and intestinal parasites of the African giant rat (Cricetomys gambianus) was carried out between January and May, 2018 in Il-orin to access their potential as reservoirs of zoonoses. A total of 60 African giant rats were caught live using single catch rat traps which were set around bushes, near human habitation. The giant rats were euthanized with chloroform and thoroughly examined for ectoparasites. The giant rats were dissected and the alimentary canal removed. Direct smear floatation and sedimentation methods were used to detect endoparasites in the animals. The prevalence of different types of endoparasites were: Hymenolepis nana (33.3 %), Hymenolepis diminuta (25.0 %), Aspicularis tetraptera (29.2 %), and Acanthocephala spp. (12.5 %), while the ectoparasites were: Ixodes rasus (37.9 %), Xenopsylla cheopis (44.8 %) and Ornithonyssus bacoti (17.2 %). African giant rats harbour quite a number of infections that can be spread to humans especially in developing countries where most communities are economically disadvantaged, thus the need to properly enlighten the populace.

Zoonotic and non-zoonotic helminths in black rats of rain-fed and irrigated areas of Swat, Khyber Pakhtunkhwa, Pakistan

Present study was conducted to get information on helminth parasites of zoonotic importance among the black rats of district Swat, Pakistan. Two hundred and sixty nine rats were captured from agricultural ecosystem of the district using live captured traps from 2011 to 2013. Captured rats were anesthetized and surveyed for the presence of ectoparasites, then were carefully dissected for investigation of endoparsites. Helminth parasites of 8 species were identified. Presence of parasite was noticed in 23.7% of sampled rats. The infection rates of sampled rats was given in order of their infectivity as Syphacia obvelata 13(4.83%), Aspiculuris tetraptera 13(4.83%), Heterakis spumosa 12 (4.46%), Hymenolepis spp. 9(3.34%), H.diminuta 8(2.97%), Hymenolepis fusa 4(1.48%), Lutziella microacetabularae 4(1.48%) and Lutziella spp. 1 (0.37%). No significant difference (P < 0.4289) was found in prevalence of parasites among areas, crops, crop stages and sex of the host while adult rats were found more infected than sub-adults. S. obvelata and A. tetraptera were the most common species of helminths while Lutziella sp., 1 (0.37%) was found only in one host. Rattus rattus (the black rat) was regarded as the host of helminth parasites of zoonotic importance, therefore the hidden health hazards of this rodent species needed to be considered to prevent infectivity of humans. Current study was concluded that Rattus rattus harbored a wide variety of helminth parasites which shows a hidden risk to inhabitants of the region. Monitoring rats’ population in settle areas and educating the local community about the risk of rat borne parasitic diseases transmission through rats appears to be absolutely essential.

Helminth fauna of small mammals from public parks and urban areas in Bangkok Metropolitan with emphasis on community ecology of infection in synanthropic rodents

In 2018, extensive field studies of diversity and prevalence of helminth infection in synanthropic rodents and non-rodent small mammals from public parks and citified areas in the Bangkok Metropolitan were conducted. Rattus rattus complex was the dominant small mammal in public parks. Of the 197 animals, 147 individuals were infected with one or more species of helminths, yielding an infection prevalence of 74.6%. Twenty-five species of helminths were recovered during necropsy. Pterygodermatites tani was the most prevalent (36.2%); other encountered species included Raillietina celebensis, Hydatigera taeniaformis (metacestode in liver tissue), Gongylonema neoplasticum and Hymenolepis diminuta. Different helminth assemblages infected three different host taxa, i.e. synanthropic Rattus spp., Tupaia belangeri (Northern treeshrew) and Suncus murinus (Asian house shrew). Nine species of possible zoonotic helminths were identified. The focus on synanthropic rats influenced the findings of helminth diversity by either host intrinsic or extrinsic factors. A significant positive correlation was found between host body mass and helminth species richness. Greater helminth species richness was found in rats from public parks compared with animals from citified areas (e.g. inside buildings or offices). Also, helminth species richness was negatively correlated with the proportion of post-flooding/rain-fed land. These results provide essential information for assessing the incidence of potential zoonotic health threats in Bangkok and updating research in parasite ecology.

Zoonotic Gastrointestinal Helminths in Rodent Communities in Southern Guatemala

Rodents are reservoirs and hosts of several pathogens around the world, including zoonotic parasite species. This study aimed to determine the occurrence of zoonotic gastrointestinal helminths in rodents captured inside households in a rural community from southern Guatemala. Sixty-nine rodents were captured in 33% (49/148) of the surveyed households, including Rattus rattus, Rattus norvegicus, Mus musculus, and Sigmodon hispidus. Thirty-six percent (25/69) of these rodents (3 Rattus and 22 Mus musculus), from 45% (22/49) of the households, were parasitized with at least 1 gastrointestinal helminth species. Helminths from 6 species were identified: Hymenolepis diminuta, Moniliformis moniliformis, Heterakis spumosa, Nippostrongylus sp., Strongyloides sp., and Syphacia sp. Two zoonotic species were found in Rattus, H. diminuta in R. rattus (1/6), and M. moniliformis in R. norvegicus (1/1). Coinfection with other non-zoonotic helminth parasites, such as He. spumosa and Strongyloides sp., also was observed in the Rattus genus. Mus musculus had only non-zoonotic helminths: He. spumosa, Nippostrongylus sp., and Syphacia sp. being the most common, and He. spumosa (96%) followed by Nippostrongylus sp. (48%), with a higher presence in males than females, with a similar proportion in adult and young individuals. This is the first report of zoonotic and non-zoonotic helminths parasites in rodents from Guatemala.

Zoonotic Helminthiases in Rodents (Bandicota indica, Bandicota savilei, and Leopoldamys edwardsi) from Vientiane Capital, Lao PDR

Zoonotic helminths of three rodent species, Bandicota indiaca, Bandicota savilei, and Leopoldamys edwardsi, were investigated in Vientiane capital, Lao PDR. A total of 310 rodents were infected with 11 species of helminth parasites. There were 168 (54.2%) of 310 rodents infected with zoonotic helminths. From our results, there are six recorded zoonotic helminth species, and the highest prevalence was exhibited by Raillietina sp. (30.7%), followed by Hymenolepis diminuta (17.7%), Hymenolepis nana (2.6%), Echinostoma ilocanum (1.9%), Echinostoma malayanum (1.3%), and Angiostrongylus cantonensis (1%). This is the first study of zoonotic helminths in L. edwardsi and the first report of H. diminuta, H. nana, E. ilocanum, and E. malayanum in Bandicota indica and B. savilei, and the first demonstration of A. cantonenensis in B. indica in Lao PDR. From our results, these three rodents are potentially important reservoir hosts of zoonotic helminths. Thus, effective control programs should be considered for implementation to prevent the transmission of these zoonoses in this area.

Morphological, Molecular, and Pathological Appraisal of Hymenolepis nana (Hymenolepididae) Infecting Laboratory Mice (Mus musculus)

Hymenolepis nana, typically a parasite found in conventionally established mouse colonies, has zoonotic potential characterized by autoinfection and direct life cycle. The objective of this study was to determine the rate of parasite infection in laboratory mice. The hymenolepidide cestode infected 40% of the 50 mice sampled. The rate of infection in males (52%) was higher than in females (28%). Morphological studies on the cestode parasite showed that worms had a globular scolex with four suckers, a retractable rostellum with 20-30 hooks, and a short unsegmented neck. In addition, the remaining strobila consisted of immature, mature, and gravid proglottids, irregularly alternating genital pores, lobulated ovaries, postovarian vitelline glands, and uteri with up to 200 eggs in their gravid proglottids. The parasite taxonomy was confirmed by using molecular characterization based on the sequence analysis of the mitochondrial cytochrome c oxidase subunit 1 (mtCOX1) gene. The parasite recovered was up to 80% identical to other species in GenBank. High blast scores and low divergence were noted between the isolated parasite and previously described H. nana (gb| AP017666.1). The phylogenetic analysis using the COX1 sequence places this hymenolepidid species of the order Cyclophyllidea.

Worldwide overview of human infections with Hymenolepis diminuta

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

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

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

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.

Oxyurid nematodes of pet rodents in Slovakia - a neglected zoonotic threat

The role of rodents as reservoirs of helminths of public health importance is not well known. The zoonotic potential of Syphacia spp. has been confirmed; therefore, the study aimed to estimate the occurrence of oxyurid nematodes in small rodents from pet shops and breeding clubs in Slovakia. Fecal samples of 586 pet rodents kept in 133 cages were collected between 2016 and 2018 and examined by Faust´s flotation method. Four species of oxyurid nematodes, Syphacia muris, S. obvelata, Aspiculuris tetraptera and Paraspidodera uncinata were detected. A. tetraptera was found in the faecal samples of all rodent species included in this survey. The number of positive boxes varied from 5.4% in hamsters to 70.0% with mice. The prevalence of Syphacia muris was highest in Mongolian gerbils where up to 75.0% boxes were positive; S. obvelata was found in 26.7% of boxes with mice, 25.0% of boxes with Mongolian gerbils and 3.2% of boxes with rats. The high prevalence of Syphacia spp. in all animal species points out the infection risk for humans. Animals offered for sale are often in close contact with human beings; therefore they should be regularly tested for parasites and then effectively dewormed.

Internal parasitic burdens in brown rats (Rattus norvegicus) from Grenada, West Indies

This study identified the endoparasites in Brown rat (Rattus norvegicus) during May to July 2017 in Grenada, West Indies. A total of 162 rats, 76 females and 86 males were trapped from St. George and St. David parishes in Grenada. The collected fecal samples were examined for parasitic eggs and/or oocysts using simple fecal flotation technique. Adult parasites found in the intestinal tract were examined for identification. The overall prevalence of intestinal parasites among rats was 79 %.

Ten helminth species were recovered, several of which were reported for the first time in rodents in Grenada. The internal parasites consist of seven nematodes (Angiostrongylus spp., Nippostrongylus braziliensis, Heterakis spumosa, Strongyloides ratti, Aspiculuris tetraptera, Syphacia spp. and Protospirura spp.), one cestode (Hymenolepsis diminuta), one acanthocephalan (Moniliformis moniliformis) and one protozoa species (Eimeria spp.). The most prevalent zoonotic species were Angiostrongylus spp. (35.2%), Hymenolepsis diminuta (7.4%) and Moniliformis moniliformis (3.1%). Several nonzoonotic endoparasites; which included Nippostrongylus braziliensis (50.6%), Heterakis spumosa (15.4%), Strongyloides ratti (43.2%), Aspiculuris tetraptera (2.5%), Syphacia spp. (1.9%), Protospirura spp. (1.2%) and Eimeria spp. (4.7%) were also identified. The most prevalent parasites were Nippostrongylus brasiliensis (50.6%), Strongyloides ratti (43.2%) and Angiostrongylus spp. (35.2%). Co-infections occurred with up to six species per rat showing different combinations of parasitic infections.

Patterns of helminth infections in Rattus rattus and Mus musculus from two Mayan communities in Mexico

The black rat Rattus rattus and the house mouse Mus musculus are two commensal rodent species that harbour and shed zoonotic pathogens, including helminths. The aim of this survey was to study the helminth community and the patterns of infections in R. rattus and M. musculus from two Mayan communities in Mexico. Gastrointestinal helminths were isolated from 322 M. musculus and 124 R. rattus, including Gongylonema neoplasticum, Hassalstrongylus aduncus, Hassalstrongylus musculi, Hydatigera taeniaeformis metacestode, Hymenolepis diminuta, Nippostrongylus brasiliensis, Oligacanthorhynchidae gen. sp., Syphacia muris, Syphacia obvelata, Rodentolepis microstoma and Trichuris muris. The overall richness of helminths was seven in R. rattus and six in M. musculus. The results of generalized linear models showed that juvenile rodents had lower probabilities of being infected with G. neoplasticum, H. taeniaeformis and H. musculi than adult rodents. A positive association between the prevalence of S. muris and rat abundance was found. The intensity of infection with S. muris was higher in the rainy season than in the dry season; the opposite result was found for H. musculi infection. Male R. rattus harboured more S. muris specimens. The intensity of infection with T. muris was inversely associated with mouse abundance. The presence of the zoonotic H. diminuta, as well as H. taeniaeformis and R. microstoma in rodent populations indicates that there is risk of transmission, and that their entire life cycle occurs in the study area.

Morphological Re-Description and 18 S rDNA Sequence Confirmation of the Pinworm Aspiculuris tetraptera (Nematoda, Heteroxynematidae) Infecting the Laboratory Mice Mus musculus

Aspiculuris tetraptera is a heteroxynematid nematoda infecting most of the laboratory animals, occasionally mice which represent the mostly used animal for biological, medical, and pharmacological studies. The present study aimed to investigate the prevalence of nematode parasites infection in the laboratory mice Mus musculus in Egypt. Morphologically, this oxyurid possessed four distinct cephalic papillae on a cephalic plate, with three small rudimental lips carrying two sessile poorly developed labial papillae and one pair of amphidial pores. Esophagus divided into cylindrical corpus and globular bulb. Distinct cervical alae interrupted at the level of esophago-intestinal junction forming an acute angle. At the caudal end, twelve caudal papillae in male worms while an ovijector apparatus opening and a vulva surrounded by protruded lips in females were observed. The general morphological criteria include this nematode with other Aspiculuris species which were compared in the present study. Molecular characterization based on 18SSU rDNA sequencing performed to confirm the taxonomic position of this species and to documents the morphological data. Sequence alignment detects a percent of identity up to 88.0% with other Heteroxynematidae species. Phylogenetic analysis showed that the present recorded is a putative sister taxon to A. tetraptera recorded in a previous study. The SSU rDNA sequence has been deposited in the GenBank under the accession no. MG019400.

The helminth community of a population of Rattus norvegicus from an urban Brazilian slum and the threat of zoonotic diseases

Urban slums provide suitable conditions for infestation by rats, which harbour and shed a wide diversity of zoonotic pathogens including helminths. We aimed to identify risk factors associated with the probability and intensity of infection of helminths of the digestive tract in an urban slum population of Rattus norvegicus. Among 299 rats, eleven species/groups of helminths were identified, of which Strongyloides sp., Nippostrongylus brasiliensis and, the human pathogen, Angiostrongylus cantonensis were the most frequent (97, 41 and 39%, respectively). Sex interactions highlighted behavioural differences between males and females, as eg males were more likely to be infected with N. brasiliensis where rat signs were present, and males presented more intense infections of Strongyloides sp. Moreover, rats in poor body condition had higher intensities of N. brasiliensis. We describe a high global richness of parasites in R. norvegicus, including five species known to cause disease in humans. Among these, A. cantonensis was found in high prevalence and it was ubiquitous in the study area - knowledge which is of public health importance. A variety of environmental, demographic and body condition variables were associated with helminth species infection of rats, suggesting a comparable variety of risk factors for humans.

Prevalence and diversity of gastrointestinal helminths in free-ranging Asian house shrew (Suncus murinus) in Bangladesh

Background and Aim

Asian house shrew (Suncus murinus), a widely distributed small mammal in the South Asian region, can carry helminths of zoonotic importance. The aim of the study was to know the prevalence and diversity of gastrointestinal (GI) helminths in free-ranging Asian house shrew (S. murinus) in Bangladesh.

Materials and Methods

A total of 86 Asian house shrews were captured from forest areas and other habitats of Bangladesh in 2015. Gross examination of the whole GI tract was performed for gross helminth detection, and coproscopy was done for identification of specific eggs or larvae.

Results

The overall prevalence of GI helminth was 77.9% (67/86), with six species including nematodes (3), cestodes (2), and trematodes (1). Of the detected helminths, the dominant parasitic group was from the genus Hymenolepis spp.(59%), followed by Strongyloides spp.(17%), Capillaria spp. (10%), Physaloptera spp. (3%), and Echinostoma spp.(3%).

Conclusion

The finding shows that the presence of potential zoonotic parasites (Hymenolepis spp. and Capillaria spp.) in Asian house shrew is ubiquitous in all types of habitat (forest land, cropland and dwelling) in Bangladesh. Therefore, further investigation is crucial to examine their role in the transmission of human helminthiasis.

Endoparasites of Small Mammals in Edo State, Nigeria: Public Health Implications

Some small mammals occur as household pests and harbour a number of parasites that could be of public health importance. This study profiled the helminth and protozoan parasites in trapped small mammals within and around human dwelling places (houses) located across 4 major towns (Auchi, Benin, Ekpoma, and Uromi) and environs in Edo state, Nigeria. Six genera (Apodemus sp., Crocidura sp., Mastomys natalensis, Mus musculus, Rattus sp., and Sorex sp.) were identified from 502 trapped small mammals. Overall, M. musculus (71.9%) and Rattus rattus (20.1%) were the most frequently trapped. In total, on examination of blood, gastrointestinal contents, and brain tissues, 12 helminth taxa (Angiostrongylus sp., Aspicularis sp., Capillaria sp., Gongylonema sp., Heterakis spumosa, Hymenolepis diminuta, Hymenolepis nana, Mastophorus muris, Moniliformis moniliformis, Nippostrongylus brasiliensis, Strongyloides sp., Trichosomoides sp., and Trichuris sp.), and 6 protozoan parasites (Babesia sp., Trypanosoma lewisi, Plasmodium sp., Eimeria sp., Isospora sp., and Toxoplasma gondii) were isolated. Most prevalent helminths with relatively heavy mean intensity were Strongyloides sp. and Heterakis spumosa, while Plasmodium, Eimeria, and Isospora were the most prevalent protozoan parasites. Generally, intrinsic factors like sex and age had marginal influence on the rate and burden of infection in M. musculus and R. rattus. Although the infection rate and prevalence of zoonotic parasites were low, they were largely recovered in rodents from Ekpoma. This study elucidates the public health implication of the presence of zoonotic parasites in these small mammals.

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

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

Helminth Diversity in Synanthropic Rodents from an Urban Ecosystem

Richness and diversity of parasites depend on a set of interrelated factors related to the characteristics of the host, the environment and the parasites itself. In the City of Buenos Aires, rodent communities vary according to landscape structure. The goal of this paper was to study the variations of helminth richness and diversity among invasive rodent species in different landscape units of the City of Buenos Aires. 73% of the rodents were parasitized with at least one of the 10 identified helminth species. Each rodent species presented its own characteristics in terms of richness, diversity and helminth composition, keeping these characteristics still occupying more than one landscape unit. The infracommunities with greater diversity corresponded to R. norvegicus due to its high values of parasitic richness, proportion of infected hosts and parasite prevalence. Instead, R. rattus and M. musculus infracommunities had lower diversity since a high percentage of them presented a unique helminth species. Within the city, the inhabitants of shantytowns would be the most exposed to zoonotic diseases transmitted by rodents due to high abundance of rodents harboring a high parasite load, including species like Hymenolepis nana and H. diminuta, recognized worldwide from a zoonotic aspect.

New host, geographical records, and factors affecting the prevalence of helminths infection from synanthropic rodents in Yucatán, Mexico

The aim of this paper was to study the occurrence of helminths in Mus musculus and Rattus rattus from urban, suburban and rural settlements in Yucatán, Mexico; and to analyse the host factors (e.g. sex) related to helminths’ distribution. Helminths in a total of 279 rodents were surveyed by visual examination of the liver for metacestodes and faecal examination for helminth eggs using the formalin-ethyl acetate sedimentation technique. The cestodes Hydatigera taeniaeformis (metacestodes detected in the liver) and Hymenolepis diminuta, and the nematodes Aspiculuris sp., Nippostrongylus brasiliensis, Syphacia muris, Syphacia obvelata, and Trichuris muris were identified. In M. musculus, the prevalence of infection with T. muris and H. taeniaeformis was higher in the rural village compared to those in the suburban neighbourhood. For R. rattus, a higher prevalence of infection with H. diminuta was found in the urban site compared to that in the suburban site. This study reports the occurrence of H. diminuta among rodents living in close proximity to humans, representing a potential public health risk. In addition, this survey increases our understanding of dynamic transmission among intestinal helminths recorded in Yucatán, Mexico.

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.

Gastrointestinal helminth fauna of rodents from Cambodia: emphasizing the community ecology of host-parasite associations

Extensive field surveys of rodents were conducted in Cambodia from 2008 to 2014 to study the diversity and ecology of helminth infection in wild rodent populations. Gastrointestinal helminths were isolated from 14 species of rodents (569 individuals) trapped from different habitats (forest, dry land, rain-fed land and human settlements) in four provinces of Cambodia (Krong Preah Sihanouk, Mondolkiri, Pursat and Steung Treng). The average prevalence of parasitic infection was 58.5% (range, 16.0-64.7%), and 19 helminth taxa were identified in total. Trichostrongylid nematodes were the most prevalent (25.8%), followed by Raillietina sp. (14.1%), Gongylonema neoplasticum (10.7%), Syphacia muris (9.8%) and Hymenolepis diminuta (9.6%). Potential rodent-borne zoonotic helminths were also identified, and the risks of helminthiasis were discussed. The status of helminth infection and species diversity in rodents from settlements were significantly lower than in rodents from forest and peri-domesticated habitats, which indicates that habitat alteration might affect helminth infection and diversity in rodent hosts. Generalized linear models revealed that host attributes (host species and maturity) and environmental factors (habitat and geographical location) were explanatory variables for helminth infection in these rodents. Using network analyses, we showed that the oriental house rat, Rattus tanezumi, was the most central host in the rodent-helminth assemblage, based on the number of helminth taxa it shared with other rodent species. Therefore, R. tanezumi could play an important role in rodent-helminth interactions and helminth transmission to other rodent hosts.

Helminths in rodents from Wet Markets in Thailand

Only a few surveys have ever been carried out of the helminths of the commensal rodents found in the traditional wet markets that play such an important part of daily life in South-east Asia. The potential of rodents as reservoirs of zoonoses including helminths is of great interest since in these markets humans and rodents come into closer contact than in other environments and food may be indirectly contaminated via rodent faeces. Helminths in a total of 98 rats belonging to two species (Rattus norvegicus and Rattus exulans) were surveyed in eight traditional wet markets in Udon Thani, Thailand. Thirteen species of helminths were recovered, seven of which are potentially zoo-notic, with an overall prevalence of 89.8 %. Our results show that rodents in wet markets could pose a threat to human health as potential reservoirs of zoonotic helminthiases.

Potentially zoonotic helminthiases of murid rodents from the Indo-Chinese peninsula: impact of habitat and the risk of human infection

In this study, we report the potential rodent-borne zoonotic helminths in wild-caught murid rodents from four categorized habitats-forest, nonflooded land, irrigated land, and human settlement in seven localities of Thailand, Cambodia, and Lao PDR. Out of 2478 rodent samples, 735 (29.7%) were infected by at least one of the following zoonotic helminth species: Echinostoma malayanum, Echinostoma ilocanum, Plagiorchis muris, Raillietina spp., Hymenolepis diminuta, Hymenolepis nana, Cyclodontostomum purivisi, and Moniliformis moniliformis. Raillietina spp. showed the highest prevalence (13.8%), followed by H. diminuta (8.6%), H. nana (6.7%), and C. purvisi (1.0%). Habitat affected the intensity of helminth infection in murid rodent hosts. Specific habitats favoring each zoonotic helminth species are discussed in relation to the risk of human infection. Season and host maturity influenced intensity of total zoonotic helminths, but there was no influence of host gender. However, in terms of individual helminth species, female rodents were more infected by E. malayanum, E. ilocanum, and C. purvisi than males. Among the rodent species, Rattus tanezumi seems to play the most important role as a reservoir by hosting seven zoonotic heminth species. This rat is ubiquitously found in all types of the habitats, suggesting that it can act as an important bridge species, carrying parasites across different habitats.

Molecular analysis of isolates of the cestode Rodentolepis nana from the great gerbil, Rhombomys opimus

Rodentolepis nana (syn. Hymenolepis nana) is a cyclophyllidean zoonotic enteric parasite with worldwide distribution. In humans, it is more prevalent in children, especially in temperate zones. A morphologically similar species of R. nana occurs in different rodents, including gerbils. In the present study molecular characterization of five isolates of R. nana from Rhombomys opimus in the Golestan Province (n= 2) and Razavi Khorasan Province (n= 3), both in north-eastern Iran, were analysed. After DNA extraction, the internal transcribed spacer 2 (ITS2) region of the R. nana isolates was amplified and sequenced, and genetic variation was analysed. Accordingly, two isolates from the Razavi Khorasan Province showed ITS2 signatures that differed from the isolates from the Golestan Province. The third isolate from Razavi Khorasan did not reveal these specific signatures, but exhibited sparse nucleotide polymorphisms in the ITS2 sequence. The ITS gene is conserved, and variation in this fragment could be an interesting subject for further inspection of existing variation in the genome of R. nana, among different domestic and wildlife host species and from different areas.

Biotic and abiotic effects on the intestinal helminth community of the brown rat Rattus norvegicus from Rio de Janeiro, Brazil

Rattus norvegicus has attracted much attention because of its role as a reservoir of zoonotic pathogens. This work aimed to identify the intestinal helminth species in R. norvegicus and to analyse the effects of temperature, rainfall, host age and sex on the helminth community structure. Moreover, this study investigated the possible associations among helminth species in an urban population of R. norvegicus in São Gonçalo, Rio de Janeiro, sampled during the rainy and dry seasons over a span of 2 years. A total of 112 rats were infected by six species of helminths. The nematode Nippostrongylus brasiliensis was the most prevalent and abundant species, with high mean intensity in both seasons, followed by Strongyloides venezuelensis, Heterakis spumosa, Raillietina sp., Hymenolepis nana and Moniliformis moniliformis. Co-occurrence was found between N. brasiliensis and S. venezuelensis and between N. brasiliensis and H. spumosa. The occurrence of S. venezuelensis was related to rainfall. The understanding of the helminth community structure in this synanthropic rat provides basic information on parasites of public health importance, as two helminth species (H. nana and M. moniliformis) recovered from rats in the urban area studied can infect humans.

Landscape characteristics influence helminth infestations in a peri-domestic rodent--implications for possible zoonotic disease

BACKGROUND

Anthropogenic habitat change often results in altered landscapes that can provide new environments where hosts, parasites and pathogens can interact. The latter can have implications for human and animal health when in close proximity to developed areas. We recorded the helminth species richness and level of infestation in the peri-domestic rodent, Rhabdomys pumilio, in three different human linked landscapes. The aim was, to investigate the potential of R. pumilio to act as a reservoir host for zoonotic helminths and to compare the effect of anthropogenic habitat change on its parasite infestation patterns.

METHODS

Rodents (n = 518) were trapped in natural areas (nature reserves) and in three human linked landscapes (crop, livestock and urban fragments). Gastrointestinal parasite burdens were recovered and helminths identified from each animal. Generalized linear models were applied to investigate the effect of different landscape types on helminth infestation.

RESULTS

Rhabdomys pumilio was the most abundant rodent species within each landscape type. Eight helminths species were recovered and overall helminth prevalence was 86.68%. Mean helminth species richness, prevalence and abundance were significantly higher in crop fragments compared to natural landscapes and overall lower for nematodes in livestock and urban areas. Cestode prevalence showed a tendency to be elevated at anthropogenic linked landscape types.

CONCLUSIONS

Host parameters and parasite infestations were strongly influenced by landscape characteristics. Resource-rich landscapes (crop fragments) provide favorable conditions for helminth infestations, while landscapes that are more closely associated with humans (livestock and urban landscapes) pose a larger risk by zoonotic species.

Pterygodermatites (Mesopectines) niameyensis n. sp. (Nematoda: Rictulariidae), a parasite of Mastomys natalensis (Smith, 1834) (Rodentia: Muridae) from Niger

Pterygodermatites (Mesopectines) niameyensis n. sp. is described from Mastomys natalensis in Niamey/Niger (West Africa). It differs from other species of same subgenus by the morphology of the head, which presents 4 simple cephalic papillae and nearly axial oral opening, a number of caudal papillae, precloacal cuticular formations, and the spicule length/body length ratio. Scanning electron microscopy shows the presence of 2 pairs of lateral sensory structures for male worms.

Helminth communities in murid rodents from southern and northern localities in Lao PDR: the role of habitat and season

The helminth communities of wild murid rodents were investigated in Luang Prabang and Champasak province, Lao PDR. Thirteen species of rodents (404 individuals) were infected by 19 species of parasites (2 trematode, 3 cestode, 14 nematode species). Four of the recorded helminth species (Echinostoma malayanum, Raillietina sp., Hymenolepis diminuta and H. nana) are known to cause potential zoonotic helminthiases of medical importance in the South-East Asian region. Individual helminth infection was significantly higher in the wet season. Habitat significantly influenced individual helminth species richness and individual helminth abudance, with a decrease of individual helminth species richness and individual helminth abundance from forest habitat to agricultural and human settlement habitats. The reduction of helminth diversity and abundance is discussed in relation to the ongoing increase of human influence on habitats in Lao PDR.

Isolation and molecular characterization of Leptospira interrogans and Leptospira borgpetersenii isolates from the urban rat populations of Kuala Lumpur, Malaysia

Rats are considered the principal maintenance hosts of Leptospira. The objectives of this study were isolation and identification of Leptospira serovars circulating among urban rat populations in Kuala Lumpur. Three hundred urban rats (73% Rattus rattus and 27% R. norvegicus) from three different sites were trapped. Twenty cultures were positive for Leptospira using dark-field microscopy. R. rattus was the dominant carrier (70%). Polymerase chain reaction (PCR) confirmed that all isolates were pathogenic Leptospira species. Two Leptospira serogroups, Javanica and Bataviae, were identified using microscopic agglutination test (MAT). Pulsed-field gel electrophoresis (PFGE) identified two serovars in the urban rat populations: L. borgpetersenii serovar Javanica (85%) and L. interrogans serovar Bataviae (15%). We conclude that these two serovars are the major serovars circulating among the urban rat populations in Kuala Lumpur. Despite the low infection rate reported, the high pathogenicity of these serovars raises concern of public health risks caused by rodent transmission of leptospirosis.

Prevalence of gastrointestinal helminth infections in rodents of Tarai region of Uttarakhand

The present work was aimed to investigate helminth biodiversity among rodents in order to evaluate the threat for helminth transmission to humans since they act as a potential source of parasitic zoonoses. In this study, faeces of 43 black rats (Rattus rattus) and 35 house mice (Mus musculus) were collected from various habitats viz. domestic places and agricultural fields of different parts of tarai region of Uttarakhand. These faecal samples were examined for the presence of parasitic eggs, adult and segments of the worms. The study revealed that the rodents were infected with 5 genera of helminth parasites, i.e. Hymenolepis nana, Hymenolepis diminuta, Syphacia muris, Capillaria hepatica, Trichuris muris and other strongyle eggs (2 species of cestodes and 4 species of nematodes). Adult Syphacia muris and segments of Hymenolepis nana were also recovered from faecal droppings. Of the 43 samples of black rat, all (100 %) and of the 35 samples of mice 9 (25.71 %) were found positive for one or more than one species of parasitic infections. Greater infection of H. diminuta 19 (44.18 %) followed by H. nana 17 (39.53 %) was seen in rat whereas mice were mostly infected with H. nana. The diversity and prevalence of various parasites reported here within domestic habitats may suggest that these can pose a high risk of helminth transmission to human population and are thus of considerable public health importance.