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Nelson medium and modified PYNFH medium were used for the axenic culture of the Naegleria fowleri clinical strain LDL to compare the effects of different temperatures on the organism's growth. In addition, Nelson medium supplemented with 1% peptone (N pep) and modified PYNFH medium without peptone (PYNFH − pep), without yeast extract (PYNFH − yext), without folic acid (PYNFH − folac), and without yeast nucleic acid (PYNFH − yna) were used in order to compare the various effects of these medium components. In general, N. fowleri grew best at 37 C. The highest trophozoite densities per 10,000 μm2 were observed when N pep and PYNFH − yext were used. At 25, 37, and 43 C, the growth density profile values were 50.5 ± 6.36 vs. 58 ± 1.41; 2,550 ± 494.97 vs. 2,100 ± 141.42; and 1,735 ± 21.21 vs. 1,800 ± 14.14, respectively. On the other hand, PYNFH − pep gave the lowest growth with its highest cell densities being 9 ± 1.41 at 25 C, 108 ± 7.07 at 37 C, and 169 ± 15.55 at 43 C. When the various medium components were compared, supplementation with peptone promoted parasite growth. Besides, yeast extract had an inhibitory effect and was able to swamp the growth promoting effect of peptone. Thus N pep and PYNFH − yext are recommended as the best media for in vitro culture of N. fowleri.
Macracanthorhynchus ingens is an acanthocephalan parasite commonly found in raccoons (Procyon lotor) in the United States. Little is known, however, about the prevalence and distribution of M. ingens in raccoons in Canada. Our objective was to investigate the prevalence, distribution, and risk factors associated with M. ingens infection in raccoons in southern Ontario, Canada. Raccoon carcasses submitted to the Ontario/Nunavut region of the Canadian Wildlife Health Cooperative for post mortem from June 2016 to January 2017 (n = 380) were examined for the presence of gastrointestinal helminths. Macracanthorhynchus ingens was found in raccoons from areas across southern Ontario where carcasses were submitted. The prevalence of M. ingens in our sample was 14.0% (95% CI = 10.6–17.8) with a median of 4 worms per infected host (range 1–46). Univariable logistic regression modeling was conducted to examine the influence of age, sex, season, degree of urbanization (urban/suburban/rural), and Baylisascaris procyonis infection on the presence of M. ingens. Significant associations were found between M. ingens infection and degree of urbanization as well as B. procyonis infection. No associations were found between M. ingens infection and age, sex, or season. To our knowledge, this is the first report describing the prevalence and distribution of M. ingens in raccoons in Canada.
Serological tests are needed to estimate the prevalence of Taenia solium cysticercosis in endemic rural areas. The predictive value of serum antibody levels to diagnose porcine cysticercosis and human neurocysticercosis (NC) was herein assessed by ELISA using serum samples from 247 backyard pigs (141 without cysticercosis and 106 with cysticercosis) and 183 human subjects (116 non-NC subjects and 67 NC patients) in central Mexico diagnosed by necropsy and computed tomography, respectively. A sensitivity of 77.3 and 92.5% and a specificity of 88.6 and 100% were found to diagnose porcine and human cysticercosis, respectively. The prevalence of porcine and human cysticercosis in the state of Morelos was estimated by ELISA. Anti-cysticercal antibodies were found in 8.4 and 19.02% of assayed sera from 1,811 humans and 804 pigs, respectively. Marginalization and living in the eastern region were risk factors for humans, whereas free-roaming, medium marginalization levels and living in Sierra de Huautla were risk factors for pigs. These results clearly evidence the persistence of cysticercosis transmission and neurocysticercosis in a region neighboring Mexico City, pointing out the need to apply effective measures already available for its control.
The objective of this study was to examine the efficacy of 7.5% tea tree oil (TTO) eyelash shampoo on the density of Demodex (Acari: Demodicidae) and ocular symptoms in patients with demodectic blepharitis. A total of 135 patients diagnosed with demodectic blepharitis, following clinical inspection and parasitological examinations, were included in the study. Patients were treated with eyelash shampoo, with or without TTO. Full Demodex reduction was attained in 36% of the patients who used eyelash shampoo with TTO, and the average Demodex count was reduced from 6.33/eyelash to zero (P < 0.001). In contrast, the average Demodex count in patients who did not achieve full reduction (64%) was reduced from 12.46/eyelash to 4.15/eyelash (P < 0.001). Full reduction was observed in 11.7% of patients who used TTO-free eyelash shampoo, and average Demodex count reduced from 2.00/eyelash to zero (P = 0.017). The average Demodex count was reduced from 11.98/eyelash to 7.91/eyelash in patients (88.3%) who did not achieve full reduction (P = 0.024). Additionally, ocular symptom scores (which are generated based on subjective experiences of itching, burning, the feeling of a foreign body in the eye, eye redness, and cylindrical dandruff) were reduced significantly (P < 0.001) in patients who used the eyelash shampoo with TTO. The symptom scores remained almost the same in patients who used TTO-free eyelash shampoo (P > 0.05). In conclusion, it was determined that eyelash shampoo with TTO is 3 times more effective at achieving full Demodex reduction, significantly reducing the Demodex count, and relieving ocular symptoms in patients where full reduction cannot be attained, without adverse side effects.
This study verifies the identity of adult specimens of the parasite Profilicollis chasmagnathi (Acanthocephala, Polymorphidae) recovered from kelp gulls Larus dominicanus (Aves, Laridae), and cystacanths found in crabs Cyrtograpsus altimanus (Crustacea, Decapoda) from the southwestern Atlantic coast. The life cycle of this parasite is elucidated in the intertidal zone of Patagonia, Argentina, based on morphological and molecular data. Preferences by size and sex of the intermediate host and seasonal variation of this parasite are provided, contributing to the knowledge of this host-parasite association.
Two species of acanthocephalans are described from fishes caught along the Pacific coast off eastern Vietnam in 2016: (1) Neorhadinorhynchus nudum (Harada, 1938) Yamaguti, 1939 (Cavisomidae) from the frigate tuna Auxis thazard (Lacépède) (Scombridae) in Nha Trang, Pacific south Vietnam, and (2) Heterosentis paraholospinus n. sp. (Arhythmacanthidae) from 3 species of fish: the common ponyfish Leiognathus equulus (Forsskål) (Leiognathidae) and the torpedo scad Megalaspis cordyla (Linn.) (Carangidae) off Nha Trang and Binh Thuân, respectively, and the yellowspotted ponyfish Nuchequula flavaxilla Kimura, Kimura, and Ikejima (Leiognathidae) at Quang Ninh in Pacific waters of Vietnam. Females of N. nudum are fully described for the first time in the Pacific Ocean. Heterosentis paraholospinus n. sp. is similar to Heterosentis holospinus Amin, Heckmann, and Ha, 2011, in having an unspined anterior trunk cone, nucleated pouch at the posterior end of the receptacle, and spines covering the entire trunk, but it differs in having a long cylindrical trunk, lemnisci much longer than the receptacle, more and different-sized proboscis hooks, and subterminal female gonopore. Biogeographical notes are discussed for both genera.
Nematodes are common in the parasite communities of North American freshwater fishes, and the majority of them belong to 1 conventional order, Spirurida Chitwood, 1933. Within the Spirurida, the superfamilies Habronematoidea Chitwood and Wehr, 1932 and Thelazioidea Sobolev, 1949 have undergone considerable diversification. The dominant families of these 2 superfamilies, Cystidicolidae Skrjabin 1946 and Rhabdochonidae Railliet, 1916, respectively, are particularly common, widely distributed, and diverse, especially in North America, yet their phylogenetic relationships remain largely unexplored. In this study, we use near complete sequences of the 18S rRNA genes (SSU rDNA) from species in 6 genera (Capillospirura Skrjabin, 1924, Cystidicola Fischer, 1798, Salmonema Moravec, Santos and Brasil-Sato, 2008, Rhabdochona Railliet, 1916, Spinitectus Fourment, 1883, and a putative new cystidicolid in mooneyes, Hiodontidae), along with a species of Hedruris Nitzsch, 1812 from newts as a surrogate for the fish parasite Hedruris tiara VanCleave and Mueller, 1932, to explore their phylogenetic relationships. These sequences, together with available sequences from a range of other nematodes, including fish nematodes in other groups (Camallanoidea and ‘Seuratoidea'), were analyzed using Bayesian inference and maximum likelihood. The results from both analyses indicate, for the first time, support for the close relationships of the sturgeon parasite Capillospirura with Ascarophis van Beneden, 1871 and Cystidicola; the relationship of the cystidicolid from Hiodontidae with Salmonema of salmonid fishes; the monophyly of the 2 dominant spiruridan genera of fishes, Rhabdochona and Spinitectus; and for previous relationships among Nearctic Spinitectus spp. The results also indicate a closer relationship of Rhabdochona and Spinitectus than is suggested by their conventional classification and reject the monophyly of Habronematoidea, Thelazioidea, and Cystidicolidae. Hedruridae appears to be an early branching lineage of spirurins. Finally, the pattern of association between the fish parasites in this study and their hosts indicates, with few exceptions, ecologically driven diversification events involving host shifting not related to the phylogenetic relationships of their hosts.
Five new species of the elasmobranch tapeworm genus AnthocephalumLinton, 1890 (Rhinebothriidea: Anthocephaliidae Ruhnke, Caira and Cox, 2015) are described from the mangrove whipray, Urogymnus granulatus (Macleay) from the Solomon Islands and northern Australia. Anthocephalum blairi n. sp., Anthocephalum gravisi n. sp., Anthocephalum haroldsoni n. sp., Anthocephalum mounseyi n. sp., and Anthocephalum ruhnkei n. sp. differ from one another and their congeners based on quantitative and qualitative features of the scolex and proglottid anatomy. Species boundaries recognized by these distinguishing morphological features are supported by a maximum likelihood phylogenetic analysis based on combined 18S rDNA and 28S rDNA (D1–D3) sequence data showing the new species as independent lineages among 13 of the 18 species of Anthocephalum described to date. Several morphological features (the possession of columns of vitelline follicles that are interrupted by the ovary, a uterus that does not extend to the anterior margin of the proglottid but stops short in the anterior region of the field of testes, proximal surfaces of the marginal loculi covered with acicular filitriches only throughout, or with gladiate spinitriches and acicular filitriches throughout, and proximal bothridial surfaces with gladiate spinitriches and acicular filitriches) are collectively exhibited by the 5 new species and have not been documented previously in other species of Anthocephalum. The genus is herein amended to reflect these features. Additionally, the replacement name Anthocephalum centrurum (Southwell, 1925) Ruhnke, 1994 is reinstated as the valid name for the type species of the genus, Anthocephalum gracileLinton, 1890, with the latter being the junior secondary homonym of A. gracile (Wedl, 1855) Ruhnke, 1994. The description of these new species increases the number of valid species of Anthocephalum from 18 to 23.
The tapeworm Sciadocephalus megalodiscusDiesing, 1850 (Cestoda: Proteocephalidae), is redescribed based on newly collected specimens parasitizing tucunare peacock bass, Cichla monoculus Agassiz, 1831 (Perciformes: Cichlidae), in the Peruvian Amazon. Even though this cestode was redescribed 2 decades ago, that redescription did not report some of the unique features of this species. The most unusual characteristics of the species are (1) peculiar formation of the uterus, with fast formation of numerous, tightly packed diverticula protruding ventrally and dorsally, with simultaneous disintegration of the ovary and vitelline follicles in the first pregravid proglottids; (2) inverted umbrella-shaped scolex with a well-developed apical sucker; (3) a large-sized, follicular (grape cluster-like) ovary, which occupies most of the central (median) third of proglottids, with the ovarian isthmus situated almost equatorially; (4) regular alternation of genital pores; (5) a well-developed internal seminal vesicle; and (6) a small-sized strobila (shorter than 6 mm) consisting of few proglottids (15–20). Preliminary molecular data reveal S. megalodiscus to be most closely related to Cichlidocestus gillesi, the type species of the recently erected Cichlidocestus de Chambrier, Pinacho-Pinacho, Hernández-Orts, and Scholz, 2017. Species of both genera parasitize Neotropical cichlids and are unique among all proteocephalids in the shape and position of the ovary. They also share other morphological characteristics unusual among other proteocephalids, and thus these 2 genera can be considered good candidates to be placed in a new, higher-level taxon such as separate subfamily or even family when a new, more natural classification of the Proteocephalidae is proposed.
The freshwater fish digenean Pseudosellacotyla lutzi (Freitas, 1941) Yamaguti, 1954 has had an unsettled taxonomic history, and has at various times been classified as a member of Nanophyetidae, Heterophyidae, Microphallidae, Faustulidae, and Cryptogonimidae. Nine individual specimens of the trahira, Hoplias malabaricus (Bloch, 1794), were sampled in the Paraná River basin, Paraná State, Brazil; 22 specimens of P. lutzi were collected. One specimen of P. lutzi was used to obtain a sequence of the domains D1–D3 of the 28S rRNA gene, and to perform a phylogenetic analysis to assess their position and classification within Plagiorchiida. The resulting tree unequivocally shows that the species, along with acanthostomines, belong to the Cryptogonimidae, corroborating recent findings based on the morphology of the cercariae, and in the characteristics of the life cycle. In addition, the study of the ultrastructure of the tegumental spines through scanning electron microscopy allowed us to characterize them as pectinate spines possessing 3 to 8 digitiform projections at their distal end and extending from the anterior to the posterior extremity of the body. This study also provides the first molecular data for a cryptogonimid from South America.
Trypanosoma evansi is the most widespread of the pathogenic salivarian trypanosomes; it causes a serious disease called surra that affects domestic animals such as camels, horses, and dogs, and often leads to reduced productivity and economic losses. Therefore, the objectives of the present study were to determine the prevalence rates of trypanosomiasis using 3 parasitological tests (wet blood film, Giemsa staining, and microhematocrit centrifugation technique) and polymerase chain reaction (PCR) among stray dogs from Riyadh Province, Saudi Arabia. In the current study, 117 dog blood samples collected from certain districts of Riyadh Province showed that 5 of 117 dogs (4.3%) were positive for the genus Trypanosoma. In addition, the findings indicated no effect of dog gender or age on parasite infection. For a more specific diagnosis, PCR amplification of the RoTat 1.2 VSG gene in 5 internal transcribed spacer1-positive samples diagnosed with Trypanosoma indicated that 2 were positive for RoTat 1.2 T. evansi. The absence of the RoTat 1.2 VSG gene in 3 of the 5 T. evansi-positive samples could be explained by the circulation of T. evansi type B in dogs from Saudi Arabia. Thus, this is the first study demonstrating T. evansi type B outside of Africa.
Thirty specimens of the Montezuma's frog Lithobates montezumae were collected in San Pedro Tlaltizapán, in the Nearctic–Neotropical transition zone of Mexico, in April 2013, in order to establish the helminth infracommunity structure harbored by this amphibian host. A total of 5,493 individual helminths were obtained, representing 6 species (3 trematodes and 3 nematodes). The depauperate structure of the helminth infracommunities established for the studied frogs herein (richness = 2.4; mean abundance = 183.1; Brillouin's diversity = 0.42) fits with those described for the 6 Ranidae species studied in the Nearctic. Three of the 6 species of helminths recovered are generalists, 2 of them with the highest values for prevalence (Falcaustra mexicana) and mean abundance (Renifer sp.). The parasite recruitment process (ingestion) determining mean richness in the helminth infracommunities studied here (ingestion) is shared with those reported for the 9 Mexican frog species for which helminthological records exist; however, in this case, mean abundance was determined by directly penetrating species. The use of aquatic habits by this anuran species likely explains why the composition of their helminth infracommunities was mainly constituted of helminths acquired in this environment (5 of 6 species). Finally, the heterogeneity of their taxonomic composition and abundance of helminth species indicate the unpredictable nature of these host–parasite associations.
The helminth fauna associated with Muller's termite frog, Dermatonotus muelleri, from the southern region of Ceará State, Brazil, was studied. The species richness was 6 helminth taxa, including cystacanths of Acanthocephala and 5 nematode species: Aplectana membranosa, Parapharyngodon silvoi, Raillietnema spectans, larvae of Physaloptera sp., and an unidentified nematode. The overall prevalence was 88.6%, with an average intensity of infection of 123.7 ± 26.3. The nematode Raillietnema spectans presented the highest prevalence and was the most abundant (d = 0.670). Host body size did not influence the intensity of infection nor the richness of helminth species. This study increases the body of knowledge about the diversity of helminth fauna associated with Dermatonotus muelleri from northeastern Brazil, extending the record of hosts and the geographic distribution of these helminth species.
After a human trichinellosis outbreak in Zlatibor District, Serbia, in 2016, Trichinella larvae were found in wild boar (Sus scrofa) meat products. One hundred and fourteen people were infected during the outbreak. The larvae were determined to be Trichinella britovi using the polymerase chain reaction method. Trichinella britovi has previously been identified in Serbia, but this is the first case of the species being confirmed in food samples linked to human trichinellosis. The results of the study confirmed that the T. britovi is able to affect human health. In addition, this study suggests the role of wild boars as reservoirs of T. britovi in Serbia.
A major public health issue, Toxoplasma gondii infection can affect humans mainly via the consumption of animal products from certain species, including small ruminants. Therefore, a regular monitoring of the infection in ovine and caprine populations is advisable for the control of human and animal toxoplasmosis. Antibody detection in individual and bulk tank milk (BTM) may represent a valid alternative to serological analysis, in that its collection is easy and does not affect animal welfare. Many serological tools for milk analysis have already been validated for several parasites, including Apicomplexa. Thus, the aim of the present study was to obtain epidemiological data on T. gondii infection through the detection of antibodies in BTM of dairy goat herds from an important area for caprine dairy production (northern Italy). The performance of a commercial ELISA was first evaluated for analysis of caprine milk samples, using a panel of serum–milk pairs of goats naturally infected by T. gondii. The analysis of BTM confirmed the presence of anti-T. gondii antibodies in 59% of the samples. Toxoplasma gondii antibody positivity was more frequently found in goats reared on farms under extensive (64.9%) or semi-intensive systems (68.7%) in comparison with intensive farms (51.1%). Analysis of milk was a valid alternative to serological tests, being easily applied in large-scale epidemiological surveys and for continuous monitoring of T. gondii infection.
The endoparasite fauna of Ansell's mole-rat, Fukomys anselli (Burda, Zima, Scharff, Macholán and Kawalika) (Rodentia, Bathyergidae), was studied for the first time near Lusaka, Zambia. We recovered 7 endoparasite taxa including 5 nematodes (Hexametra sp.; Protospirura numidica Seurat, 1914; Protospirura muricola Gedoelst, 1916; Protospirura sp.; and Mammalakis zambiensisJunker, Lutermann and Mutafchiev, 2017); and 2 cestodes (Inermicapsifer sp. and Rodentolepis cf. microstoma Dujardin, 1845) from 272 individuals sampled between February 2009 and February 2010. Species richness (0–2), prevalence (14.7%), and abundance (0.44 ± 0.10) were low, probably as a result of the subterranean lifestyle of the study species. Although effect of host sex on helminth burden was largely absent, helminth burden varied with season and breeding status of the host. This may be a result of seasonal variation in burrow size in response to rainfall, but also the division of labor present in the study species.
Rodents are known to be reservoir hosts of Toxoplasma gondii infection for other animals, such as cats and pigs. From February to July 2017, 167 rats (Rattus norvegicus) were trapped in Grenada, and serum, heart, skeletal muscle, and brain were examined for T. gondii infection by serological examination (modified agglutination test, 1:25) for T. gondii antibodies and for viable parasites by bioassay in mice. Samples of heart, skeletal muscle, and brain of all rats were bioassayed in Swiss Webster (SW) outbred albino mice and interferon gamma gene knockout (KO) mice. Toxoplasma gondii was isolated from heart and brain from 1 rat; this was the only seropositive rat. The T. gondii strain was avirulent for SW mice but killed KO mice. Tissue cysts were detected in the brains of SW mice, and tachyzoites were detected in the lungs of KO mice that died of acute toxoplasmosis. The strain was propagated in cell culture, and DNA derived from cell-cultured tachyzoites was genotyped using the 10 PCR restriction fragment length polymorphisms (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico). The strain was a clonal Type III (ToxoDB genotype no. 2) strain. Although the prevalence of T. gondii in humans and animals in Grenada is high, rats seem to have little importance in the transmission of T. gondii on this island.
We provide the first report of Acanthocephala (Prosthenorchis elegans) in Mexican non-human primates. There has been no known treatment against this parasite except for surgical removal, and this has been relatively ineffective because of the small juveniles. We report the presence of P. elegans in a captive breeding colony of squirrel monkeys (Saimiri sciureus) in Mexico, and we describe a successful treatment protocol. Treatment involved 2 steps: oral administration of the drugs loperamide chlorhydrate (0.5 mg/0.9 kg/3 days) and niclosamide (0.2 mg/0.9 kg/3 days) followed by surgical removal of adult worms from the intestine. Fecal examination during treatment revealed live adults but no living juveniles and no eggs. Surgery after 1 wk of treatment revealed the presence of adults and an absence of juvenile parasites. All adults were physically extracted during the surgery. All subjects recovered from surgery within 1 wk.
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