Helminth Diversity Research Articles

Microbiota and gut ultrastructure of Anisakis pegreffii isolated from stranded cetaceans in the Adriatic Sea

BackgroundInferring the microbiota diversity of helminths enables depiction of evolutionarily established ecological and pathological traits that characterize a particular parasite-host interaction. In turn, these traits could provide valuable information for the development of parasitosis control and mitigation strategy. The parasite Anisakis pegreffii (Nematoda: Anisakidae) realizes the final stage of its life-cycle within gastric chambers of aquatic mammals, causing mild-to-moderate granulomatous gastritis with eosinophilic infiltrate, to severe ulcerative gastritis with mixed inflammatory infiltrate, often associated with bacterial colonies. However, its interaction with the host microbiota remains unknown, and might reveal important aspects of parasite colonization and propagation within the final host.MethodsMySeq Illumina sequencing was performed for the 16S rRNA gene from microbiota isolated from larvae, and uterus and gut of adult A. pegreffii parasitizing stranded striped dolphins (Stenella coeruleoalba). To assess the potential presence of Brucella ceti within isolated microbiota, Brucella-targeted real-time PCR was undertaken. In addition, TEM of the gastrointestinal tract of the infective third-stage (L3) and transitioning fourth-stage larvae (L4) was performed to characterize the morphological differences and the level of larval feeding activity.ResultsIn total, 230 distinct operational taxonomic units (OTUs) were identified across all samples (n = 20). The number of shared taxa was lower than the number of taxa found specifically in each parasite stage or organ. The dominant taxon was Mycoplasmataceae (genus Mycoplasma) in the gut and uterus of adult A. pegreffii, whereas Fusobacteriaceae (genus Cetobacterium) was the most abundant in 40% of larvae, alongside Mycoplasmataceae. No B. ceti DNA was detected in any of the microbiota isolates. TEM revealed differences in gut ultrastructure between L3 and L4, reflecting a feeble, most likely passive, level of feeding activity in L3.ConclusionsMicrobiota from L3 was more related to that of the gut rather than the uterus of adult A. pegreffii. Taxa of the larval microbiota showed qualitative and quantitative perturbations, likely reflecting the propagation through different environments during its life-cycle. This suggests an ontogenetic shift in the alpha and beta diversity of microbial communities from uterus-derived towards cetacean-derived microbiota. Although TEM did not reveal active L3 feeding, microbiota of the latter showed similarity to that of an actively feeding adult nematode.

Infection dynamics of gastrointestinal helminths in sympatric non-human primates, livestock and wild ruminants in Kenya.

BackgroundGastrointestinal parasites are neglected infections, yet they cause significant burden to animal and human health globally. To date, most studies of gastrointestinal parasites focus on host-parasite systems that involve either a single parasite or a host species. However, when hosts share habitat and resources, they may also cross-transmit generalist gastrointestinal parasites. Here we explore multi-host-parasite interactions in a single ecosystem to understand the infection patterns, especially those linked to livestock-wildlife interfaces and zoonotic risk.MethodsWe used both coprological methods (flotation and sedimentation; N = 1,138 fecal samples) and molecular identification techniques (rDNA and mtDNA; N = 18 larvae) to identify gastrointestinal parasites in nine sympatric host species (cattle, sheep, goats, wildebeest, Grant’s gazelles, Thomson’s gazelles, impala, vervet monkeys and baboons) in the Amboseli ecosystem, Kenya.ResultsWe found that the host community harbored a diverse community of gastrointestinal helminths, including 22 species and/or morphotypes that were heterogeneously distributed across the hosts. Six zoonotic gastrointestinal helminths were identified: Trichuris spp., Trichostrongylus colubriformis, Enterobius spp. Oesophagostomum bifurcum, Strongyloides stercoralis and Strongyloides fuelleborni. The dominant parasite was Trichuris spp, whose ova occurred in two morphological types. Baboons were co-infected with Strongyloides fuelleborni and S. stercoralis.ConclusionsWe found that the interface zone shared by wild ungulates, livestock and non-human primates is rich in diversity of gastrointestinal helminths, of which some are extensively shared across the host species. Closely related host species were most likely to be infected by the same parasite species. Several parasites showed genetic sub-structuring according to either geography or host species. Of significance and contrary to expectation, we found that livestock had a higher parasite richness than wild bovids, which is a health risk for both conservation and livestock production. The zoonotic parasites are of public health risk, especially to pastoralist communities living in areas contiguous to wildlife areas. These results expand information on the epidemiology of these parasites and highlights potential zoonotic risk in East African savanna habitats.

Comparison of the intestinal helminth community of the large Japanese field mouse (Apodemus speciosus) between urban, rural, and natural sites in Hokkaido, Japan

Anthropogenic ecosystem modification has affected over 80% of the global land cover. Interest in its effects on wildlife has been growing over the past several decades, specifically in regard to biodiversity and ecosystem function. Parasites are of particular interest, because they directly impact animal health, and can be transmitted to humans through the process of zoonosis. However, most studies so far tended to focus on only one or two parasites with few looking at the entire community, thereby limiting our understanding of the effects of ecosystem modification on parasitic organisms. In this study, we estimated the intestinal helminth diversity and species richness of the large Japanese field mouse (Apodemus speciosus), as well as the prevalence and abundance of each species in two modified ecosystems, a rural agricultural area and an urban park. We then compared them to a natural area to see how they have been altered. We found that diversity, prevalence, and abundance were all highly altered within both modified ecosystems, but generally to a greater degree within the urban park. However, there was great variation in the direction and degree of response of each helminth species, suggesting that generalized trends may be difficult to ascertain. Furthermore, it is important to analyze the entire helminth community, because interspecific interactions and the effect that ecosystem modification has on them may help determine what species persist.

Your infections are what you eat: How host ecology shapes the helminth parasite communities of lizards.

Understanding how parasite communities are assembled, and the factors that influence their richness, can improve our knowledge of parasite-host interactions and help to predict the spread of infectious diseases. Previous comparative analyses have found significant influences of host ecology and life history, but focused on a few select host taxa. Host diet and habitat use play key roles in the acquisition of parasitic helminths as many are trophically transmitted, making these attributes potentially key indicators of infection risk. Given the paucity of comparative studies with non-piscine, non-avian or non-mammalian hosts, it is critical to examine the degree to which host ecology influences parasite communities in other host taxa in order to identify common drivers. We examined helminth diversity in over 350 species of lizards in relation to their body mass, ecology (diet and habitat use) and life history (clutch size, and ovo- or viviparity) using previously published data. Overall, lizard species with herbivorous diets harboured fewer types of helminths (especially larval stages), with similar results for traits that were ultimately strongly associated with diet (host mass and habitat use). Large hosts tended to be herbivores with few helminth types, whereas species utilizing arboreal habitats typically consumed some animal matter and hosted more helminths. Understanding how host ecology and life history are related to their parasite assemblages has significant implications for the risk of acquiring novel parasites. Our results indicate an overwhelming influence of host diet such that many helminths may be relatively easily acquired by hosts in new ranges, or through dietary shifts.

Short Communication: The diversity of intestinal parasitic helminths in children of Silvercity, Linden, Guyana

Arthur-McKenzie J, Ansari AA. 2018. Short Communication: The diversity of intestinal parasitic helminths in children of Silvercity, Linden, Guyana. Biodiversitas 19: 1289-1293. This study was conducted in the Silvercity area, Linden, Guyana and endeavored to determine the prevalence of intestinal parasitic helminths in children aged 5-15 and the level of awareness of these parasitic infections among community members. Questionnaires were distributed to 30 households and 26 children which accounts for 40% of the population aged 5-15 using a simple random sampling method and tested during the months of February-April 2017. The fecal samples were collected from 26 children selected randomly and were analyzed using wet mount and formalin-ether sedimentation method. The highest age was 15 and the lowest 5, the mean age was 8. The results showed that there was a 57.6% (15/26) prevalence of intestinal parasitic helminths among children aged 5-15 within the Silvercity area. Among the parasites found, Ascaris lumbricoides was the most prevalent (38%; 10/26) followed by Enterobius vermicularis (19%; 5/26), Trichuris trichiura (15%; 4/26) and hookworm (3.8%; 1/26). Study also found that the level of awareness of transmission among community members was 40%.

Long-term spatiotemporal stability and dynamic changes in helminth infracommunities of spiny mice (Acomys dimidiatus) in St. Katherine's Protectorate, Sinai, Egypt.

The importance of parasites as a selective force in host evolution is a topic of current interest. However, short-term ecological studies of host-parasite systems, on which such studies are usually based, provide only snap-shots of what may be dynamic systems. We report here on four surveys, carried out over a period of 12 years, of helminths of spiny mice (Acomys dimidiatus), the numerically dominant rodents inhabiting dry montane wadis in the Sinai Peninsula. With host age (age-dependent effects on prevalence and abundance were prominent) and sex (female bias in abundance in helminth diversity and in several taxa including Cestoda) taken into consideration, we focus on the relative importance of temporal and spatial effects on helminth infracommunities. We show that site of capture is the major determinant of prevalence and abundance of species (and higher taxa) contributing to helminth community structure, the only exceptions being Streptopharaus spp. and Dentostomella kuntzi. We provide evidence that most (notably the Spiruroidea, Protospirura muricola, Mastophorus muris and Gongylonema aegypti, but with exceptions among the Oxyuroidae, e.g. Syphacia minuta), show elements of temporal-site stability, with a rank order of measures among sites remaining similar over successive surveys. Hence, there are some elements of predictability in these systems.

Associations of intestinal helminth infections with health parameters of spring-migrating female lesser scaup (Aythya affinis) in the upper Midwest, USA.

Thousands of lesser scaup (Aythya affinis) die during spring and fall migrations through the upper Midwest, USA, from infections with Cyathocotyle bushiensis and Sphaeridiotrema spp. (Class: Trematoda) after ingesting infected intermediate hosts, such as non-native faucet snails (Bithynia tentaculata). The lesser scaup is a species of conservation concern and is highly susceptible to these infections. We collected female lesser scaup from spring migratory stopover locations throughout Illinois and Wisconsin and assessed biochemical and morphological indicators of health in relation to intestinal helminth loads. Helminth species diversity, total trematode abundance, and the infection intensities of the trematodes C. bushiensis and Sphaeridiotrema spp. were associated with percent body fat, blood metabolites, hematological measures, and an index of foraging habitat quality. Helminth diversity was negatively associated with percent body fat, albumin concentrations, and monocytes, whereas glucose concentrations displayed a slight, positive association. Total trematode abundance was negatively associated with blood concentrations of non-esterified fatty acids and albumin. Infections of C. bushiensis were positively related to basophil levels, whereas Sphaeridiotrema spp. infection intensity was negatively associated with packed cell volume and foraging habitat quality. Thus, commonly measured health metrics may indicate intestinal parasite infections and help waterfowl managers understand overall habitat quality. Intestinal parasitic loads offer another plausible mechanism underlying the spring condition hypothesis.

Comparison of helminth fauna from three different habitats in the Andaman Sea coastal ecosystem, southern Thailand

Helminths of marine fish are highly diverse, impact food safety and can reflect an environmental change. Some helminths have been recognized as biological markers for coastal ecosystem evaluation. Recently, the coastal area near Tarutao Island, Satun province, southern Thailand, has been reported to be impacted by an ecological change. However, information regarding helminth biodiversity in this area is limited. Therefore, this study investigated helminths in commercially caught marine fish from three ecological areas of the coastal ecosystem near Tarutao Island. Physicochemical factors that may impact helminth diversity were also recorded. In total, 1660 marine fish (36 species) were caught using trapping and netting. Among them, at least 11 species were infected with helminths. In the parasite assemblages of these fish populations, Ligophorus spp. and Metamicrocotyla sp. specifically infected gills of Mugil cephalus, which was found in both mangrove and seagrass areas. Ligophorus spp. had the highest prevalence of infection in M. cephalus and may be a predominant species and potential biological indicator for the mangrove area. The results also revealed that helminth diversity and physiochemical factors significantly differed between the areas studied; therefore, physicochemical factors may play an important role as contributing factors that affect helminth diversity in the Andaman Sea coastal ecosystem.

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

Background and AimAsian 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 MethodsA 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.ResultsThe 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%).ConclusionThe 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.

Diversity of gastrointestinal helminths in Dall's sheep and the negative association of the abomasal nematode, Marshallagia marshalli, with fitness indicators

Gastrointestinal helminths can have a detrimental effect on the fitness of wild ungulates. Arctic and Subarctic ecosystems are ideal for the study of host-parasite interactions due to the comparatively simple ecological interactions and limited confounding factors. We used a unique dataset assembled in the early seventies to study the diversity of gastrointestinal helminths and their effect on fitness indicators of Dall’s sheep, Ovis dalli dalli, in the Mackenzie Mountains, Northwest Territories, Canada. Parasite diversity included nine species, among which the abomasal nematode Marshallagia marshalli occurred with the highest prevalence and infection intensity. The intensity of M. marshalli increased with age and was negatively associated with body condition and pregnancy status in Dall’s sheep across all the analyses performed. The intensity of the intestinal whipworm, Trichuris schumakovitschi, decreased with age. No other parasites were significantly associated with age, body condition, or pregnancy. Our study suggests that M. marshalli might negatively influence fitness of adult female Dall’s sheep.

Monitoring of parasitic diseases in productive animals in the Samara region

The purpose of the research: to monitor the epizootic situation on parasitic diseases in productive animals in the Samara region using a database. materials and methods. Research was performed at the Department of invasive diseases of Samara Research Veterinary Station Samara RVS FSBSI. Fecal samples from productive animals were examined by Fuelleborn’s method using polymerase chain reaction to visualize species-specific DNA sequences, and an immune chromatographic method in detecting of antigens Dirofilaria immitis in serum, plasma and whole blood of dogs and oocysts Giardia duodenalis in dogs’ feces. The extensity of invasion was estimated with regard to the number of analyses of biomaterial from animals whose owners consulted veterinary physicians. For the monitoring, we used the database “Parasitic diseases in productive animals and small domestic animals in the Samara region” developed in Samara RVS in 2013 which enables to monitor the health status of the animal during its lifetime as well as epizootic situation on parasitic diseases in single localities, economies, districts and in Samara region in general. Results and discussion. Research results revealed that Strongylata had been registered in 17 districts at extensity of invasion from 5 to 70%, Strongyloides, Moniezia, Trichocephala - in 10 districts (EI 10-80%), Skrjabinema - in 7 districts ( EI 5-10%), Nematodirus - in 5 districts (EI 20-80%), Parascaris, Ascaris, Paramphistomum - in 3 districts (EI 5-40%), Fasciola, Coccidia, Dictyocaulus - in 2 districts (EI 5-15%). The biggest species diversity of helminths (7 species) were found in Bolsheglushitsky, Kinelsky and Borsky districts of the Samara region. The monitoring showed the decrease in worm species diversity in 2016 in all districts of Samara region compared to 2015. Parasitic protozoans, Eimeria, were found in all districts of the Samara region. A significant reduction of worm species diversity was associated with permanent planned treatment of productive animals with anthelmintics. The results obtained were used in a number of livestock farms of the Samara region to control the epizootic situation as well as for treatment and prevention of diseases in productive animals.

Helminth community from Azara's grass mouse (Akodon azarae) in three habitats with different land use in farming systems of Argentina.

In the Pampa region of Argentina, farming activities have been performed since the beginning of the 20th century, but in the 1990s, land-use patterns rapidly changed towards intensive agriculture and poultry breeding. This study compares the helminth community of Akodon azarae (Rodentia) among three habitats with different land use in pampean agroecosystems: poultry farms, mono-cultivated fields and abandoned fields (not used for 35 years), under the prediction that there will be greater helminth richness and diversity in mice from abandoned fields compared to those from the other habitats. Nevertheless, the highest abundance of A. azarae occurred on poultry farms, the habitat most disturbed by human activity, while cultivated fields showed the lowest. Helminth richness and diversity were significantly higher on poultry farms than in the other habitats, due to the presence of Trichuris laevitestis, Protospirura numidica criceticola and cysts of Taenia taeniaeformis. We suggest that the helminth fauna of A. azarae can survive on poultry farms despite disturbance from farming activities, because rodents can move and get shelter within farm perimeter fences, where dense and high vegetation grows. This farm area could offer good conditions for geohelminth development, while chicken sheds could attract insects that are intermediate hosts of helminths with indirect life cycles. On the contrary, agrochemicals applied in cultivated fields would negatively influence helminth diversity and composition, by decreasing host populations (arthropods and rodents) and affecting free larval stages of geohelminths.

High diversity of medically important gastrointestinal rodent-borne helminths in Singapore.

Small mammals are important reservoirs of zoonotic diseases and are definitive hosts for medically important parasitic helminths. Several rodent and shrew species are peridomestic, bringing them into close contact with both humans and the intermediate hosts that maintain the transmission cycle. Here, we screened DNA extracted from large intestine tissue homogenate from 108 individuals comprised of 10 species. We detected two species known to infect humans, Dicrocoelium dendriticum and Moniliformis moniliformis. We also report the first detection of a second Angiostrongylus species in Singapore. This study demonstrates the diversity of helminths that are parasitizing the small mammals in Singapore.

Seasonal variation of gastro-intestinal helminths of three bat species in the dry forest of western Mexico

Studies on helminths of chiropterans are relatively uncommon compared to those of other animals, and seasonal changes in helminth load have been rarely examined. We characterized the gastro-intestinal helminth load of 3 bats species to test for the existence of seasonal changes in response to known seasonal environmental and bat prey fluctuations. We did not find seasonal variation in most of the cases. However, the prevalence of 4 endoparasite species was significantly higher during one of the seasons. The highest richness was registered in Pteronotus parnellii during the wet season. The effective number of species was higher during the dry season in the 3 species of Pteronotus. Diet seems to be an important driver of helminth infracommunity structure, but we found heterogeneous patterns in the relationship between diversity and load of helminths and seasonal patterns of bat's diets and abundance of potential intermediate hosts.

Checklist of Helminths of Bats from Mexico and Central America

Based on original data obtained from fieldwork conducted from January 2008 to December 2015 and from previous records from published accounts, an updated checklist of helminth parasites of bats from Mexico and Central America is presented. The checklist has been organized in four ways, first as a helminth-host list in the state of Morelos, second as a helminth-host list with taxonomic and geographic distributional information, third as a bat-helminth list with references, and last, as a summary of the host-helminth association. A total of 105 records and 67 helminth taxa (26 trematodes, 4 cestodes, and 37 nematodes [33 adult and 5 larvae]) in 27 bat species from the families Emballonuridae, Molossidae, Mormoopidae, Natalidae, Phyllostomidae, and Vespertilionidae are presented for Mexico and Central America. Eight species of helminths are unique to Central America and ten species occur in both Mexico and the isthmus. From the helminths recorded in Mexico, 34 helminth species in 19 species of bats are present in the state of Morelos. The helminth diversity represents 58% of the total recorded thus far in Mexico, yet the diversity of bats intensively surveyed for parasites in the country represents roughly 14% of the diversity of chiropterans present. This evidence suggests that these intensive examinations are necessary to complete the helminthological record for bats, especially in areas of high endemism.

Helminth community structure of 13 species of anurans from Atlantic rainforest remnants, Brazil.

This study aimed to evaluate the community composition and structure of the helminths found in 13 anuran species, and to evaluate whether this parasite community is determined by anuran characteristics. We found that the helminth fauna of the amphibians from five anuran families consisted of 13 taxa and that Cosmocercidae gen. sp. was the most prevalent taxon, followed by Oswaldocruzia subauricularis. Host body size was a determining factor of the composition and structure of the parasitic fauna. Helminth abundance and richness were positively correlated with host body size. The host Leptodactylus latrans had the highest helminth richness (n = 8). The frog Hypsiboas faber had the greatest helminth diversity (H' = 0.711). The mean helminth species richness and diversity differed significantly between host species (P < 0.05). Taken together, our data indicate that, in sympatric species of amphibians, the morphological and behavioural characteristics of the hosts are important for structuring the helminth parasite communities.

Community structure of helminth parasites in two closely related South African rodents differing in sociality and spatial behaviour.

To understand the effect of social and spatial behaviour of a host on parasite community organization, we studied species co-occurrence and nestedness of assemblages of gastrointestinal helminths in two closely related rodents, solitary and mobile Rhabdomys dilectus and social and territorially conservative Rhabdomys pumilio, and asked whether helminth communities of the two hosts are characterized by a non-random pattern and whether the occurrence or degree of this non-randomness (a) differs between hosts and (b) is associated with abundance, prevalence and diversity of helminths. We found that although the general pattern of helminth co-occurrence was similar in the two hosts, helminth infracommunities of R. dilectus and R. pumilio differed in the relative frequency of positive and negative pairwise species co-occurrences (only positive in the former and both positive and negative in the latter). Nestedness-related patterns in helminth infracommunities were found in R. pumilio (predominantly anti-nested) but not R. dilectus (predominantly non-nested), whereas the opposite was the case for their component communities (non-nested versus nested, respectively). The level of infection was generally associated with the manifestation of non-randomness in helminth assemblages. Different infection parameters affected different structure patterns in the two hosts. We concluded that community structure of helminths in Rhabdomys spp. results from complex interactions between parasite- and host-associated factors.

Helminth Fauna Associated with Three Neotropical Bat Species (Chiroptera: Mormoopidae) in Veracruz, México.

Bats are recognized as potential hosts of pathogens exploiting the food chain to reach them as definitive hosts. However, very little is known about their endoparasites, especially for Neotropical bats. In this study, we assessed the helminth fauna associated with 3 insectivorous bat species roosting in the same single hot cave in central Veracruz, México: Mormoops megalophylla, Pteronotus davyi, and Pteronotus personatus. During a period of 1 yr (April 2007-2008), 135 mormoopid bats in total were collected and examined for helminths. Six parasite species representing 3 types of intestinal helminths were found: 1 cestode Vampirolepis elongatus; 2 trematodes Maxbraunium tubiporum and Ochoterenatrema labda; and 3 nematodes Linustrongylus pteronoti, Molineidae gen. sp., and Capillaria sp. Overall, trematodes were the most abundant parasite group (72.4%), followed by nematodes (20.7%) and cestodes (6.9%). Species-accumulation curves suggest that the worms collected (n = 1,331) from these 6 parasite species comprise the helminth fauna associated with the 3 bat populations studied. The only species shared by the 3 bat species was Capillaria sp. Most (5/6) of the helminth species recorded use Lepidoptera and Diptera as intermediate hosts; therefore, diet is likely the main source of infection. Although insectivorous bats are considered dietary generalist species, the differences found in helminth diversity in these sympatric populations of closely related bat species, suggest that diet partitioning occurs in mormoopid bat communities. Helminths tend to exploit the food chain to reach their final hosts; therefore, studying these parasites can provide useful information to further understand the biology of bats.

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.

Helmintos parásitos en heces de manatí Antillano Trichechus manatus manatus (Sirenia: Tricheachidae) en México: Golfo de México y Caribe

Background. Low helminth diversity has been reported in West Indian manatees (Trichechus manatus ). Most studies were conducted on the Florida sub species T. m. latirostris in subtropical environments, therefore limited information is available for the tropical Antillean subspecies T. m. manatus. In Mexico, there are apparently two population units of T. m. manatus. Goals. The objective of this study was to survey the presence and prevalence of helminth parasite eggs in the feces of T. m. manatus from the Gulf of Mexico (GM) and Caribbean coasts (CAR) of Mexico. Methods. We used 31 fecal samples collected from GM (n = 22) and CAR (n = 9), from 2005 to 2008. Feces were fixed and preserved in 70% ethanol until analysis. Both floatation and sedimentation techniques were used. Helminth eggs were identified using specialized literature and graphic catalogs. Results. We found parasite eggs in 61.2% of feces; all samples from CAR had helminths. We documented eggs from five helminths: three digenetic (Chiorchis fabaceus, C. groschafti, and Pulmonicola cochleotrema) and two Nematoda (Heterocheilus tunicatus and Ascarididae gen. sp.). Two species were found exclusively from GM, one exclusively from CAR, and two species were common to both locales. Conclusions. Diversity was consistently low in the samples. Four of the species found are common to Florida and Caribbean islands and one is a new registry for this host. Future examination of manatee carcasses could confirm the presence of adult helminth species for new registries for this host.