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Journal: The Journal of parasitology


Baracktrema obamai n. gen., n. sp. infects the lung of geoemydid turtles (black marsh turtle, Siebenrockiella crassicollis [type host] and southeast Asian box turtle, Cuora amboinensis) in the Malaysian states of Perak, Perlis, and Selangor. Baracktrema and Unicaecum Stunkard, 1925 are the only accepted turtle blood fluke genera having the combination of a single cecum, single testis, oviducal seminal receptacle, and uterine pouch. Baracktrema differs from Unicaecum by having a thread-like body approximately 30−50× longer than wide and post-cecal terminal genitalia. Unicaecum has a body approximately 8−12× longer than wide and terminal genitalia that are anterior to the distal end of the cecum. The new genus further differs from all other accepted turtle blood fluke genera by having a cecum that is highly convoluted for its entire length, a spindle-shaped ovary between the cirrus sac and testis, a uterine pouch that loops around the primary vitelline collecting duct, a Laurer’s canal, and a dorsal common genital pore. Phylogenetic analysis of the D1-D3 domains of the nuclear large subunit ribosomal DNA (28S) revealed, with high nodal support and as predicted by morphology, that Baracktrema and Unicaecum share a recent common ancestor and form a clade sister to the freshwater turtle blood flukes of Spirorchis, paraphyletic Spirhapalum, and Vasotrema and that, collectively, these flukes were sister to all other tetrapod blood flukes (Hapalorhynchus + Griphobilharzia plus the marine turtle blood flukes and schistosomes). Pending a forthcoming emended morphological diagnosis of the family, the clade including Spirorchis spp., paraphyletic Spirhapalum, Vasotrema, Baracktrema, and Unicaecum is a likely placeholder for “Spirorchiidae Stunkard, 1921” (type genus Spirorchis MacCallum, 1918; type species Spirorchis innominatus Ward, 1921). The present study comprises the 17th blood fluke known to infect geoemydid turtles and the first proposal of a new genus of turtle blood fluke in 21 yr.

Concepts: Schistosoma, Digenea, Turtle, Reptile, Turtles, Box turtle, Cuora, Cuora amboinensis


One of the recalcitrant questions regarding the evolutionary history of clitellate annelids involves the feeding preference of the common ancestor of extant rhynchobdellid (proboscis bearing) and arhynchobdellid (jaw bearing) leeches. Whereas early evidence, based on morphological data, pointed towards independent acquisitions of blood feeding in the 2 orders, molecular-based phylogenetic data suggest that the ancestor of modern leeches was a sanguivore. Here, we use a comparative transcriptomic approach in order to increase our understanding of the diversity of anticoagulation factors for 3 species of the genus Placobdella, for which comparative data have been lacking, and inspect these in light of archetypal anticoagulant data for both arhynchobdellid and other rhynchobdellid species. Notwithstanding the varying levels of host-specificity displayed by the 3 different species of Placobdella, transcriptomic profiles with respect to anticoagulation factors were largely similar - this despite the fact that Placobdella kwetlumye only retains a single pair of salivary glands, as opposed to the 2 pairs more common in the genus. Results show that 9 different anticoagulant proteins and an additional 5 putative anti-hemostasis proteins are expressed in salivary secretions of the 3 species. In particular, an ortholog of the archetypal, single-copy, anticoagulant hirudin (not previously available as comparative data for rhynchobdellids) is present in at least 2 of 3 species examined, corroborating the notion of a single origin of blood feeding in the ancestral leech.

Concepts: Evolution, Species, Phylogenetic tree, Annelid, Salivary glands, Ancestor, Leech, Hematophagy


Abstract :  The seroprevalence of Toxoplasma gondii infection in sheep in southern Mexico is largely unknown. Antibodies to T. gondii were determined in serum samples of 429 sheep from 4 farms in 2 geographical regions in Oaxaca State, Mexico, using the modified agglutination test (MAT); 99 (23.1%) of the 429 sheep had positive MAT titers: 1:25 in 35, 1:50 in 18, 1:100 in 7, 1:200 in 1, 1:400 in 3, 1:800 in 10, 1:1,600 in 5, and 1:3,200, or higher, in 20. Seroprevalence of T. gondii infection varied with management, breed of sheep, and location. It was significantly higher in sheep raised under semi-intensive (grazed on cultivated pasture and hay) conditions than in those raised under semi-extensive conditions (grazed on communal natural grass land). The seroprevalence of T. gondii infection was significantly higher in mixed-breed sheep than in pure breeds. Sheep raised in temperate climate in municipalities at 1,560-1,600 m above sea level (Central Valley region) had a significantly higher seroprevalence of T. gondii infection than those raised in semiarid and warm-humid climates in municipalities at 1,020-1,080 m of altitude (Cañada region) (29.8% vs. 7.1%, respectively). This is the first report of T. gondii infection in sheep in Oaxaca State, Mexico.

Concepts: Climate, Toxoplasmosis, Toxoplasma gondii, Mexico, Oaxaca


Abstract :  Theilerioses and babesioses are important diseases in Iranian sheep. The present study was undertaken to identify and classify/specify Theileria spp. and Babesia spp. in sheep and vector ticks. Investigation was carried out from 2009 to 2011 in the Khorasan Razavi Province, Iran. In total, 302 sheep originating from 60 different flocks were clinically examined and their blood collected. In addition, from the same flocks, ixodid ticks were sampled. Stained blood smears were microscopically examined for the presence of Theileria and Babesia organisms, and a semi-nested PCR was used for subsequent molecular specification. From the ticks, salivary glands and uterus were isolated and subsequently analyzed by semi-nested PCR. Piroplasm organisms were observed in 29% of the blood smears with low parasitemia, whereas 65% of the blood samples yielded positive PCR findings. The presence of Theileria ovis (55.6%), Theileria lestoquardi, and mixed infection with Theileria spp. and Babesia ovis were detected by semi-nested PCR in 0.3%, 5.6%, and 0.99%, respectively. In total, 429 ixodid ticks were collected from different areas of the province. The most prevalent ticks were Rhipicephalus turanicus (n = 376; 87.6% of the total), followed by Hyalomma marginatum turanicum (n = 30; 7.0%), Dermacentor raskemensis (n = 12; 2.8%), Hyalomma anatolicum anatolicum (n = 7; 1.6%), Dermacentor marginatus (n = 2; 0.5%), Rhipicephalus bursa (n = 1; 0.2%), and Haemaphysalis sp. (n = 1; 0.2%). Of the positive R. turanicus samples, 5 (5.7%) were infected with T. ovis and 2 (2.9%) with T. lestoquardi. Neither Babesia ovis nor Babesia motasi infection was detected in salivary glands or uterine samples of the ticks. The results also suggest that R. turanicus could be the vector responsible for transmission of the 2 Theileria species.

Concepts: Lyme disease, Tick, Ixodidae, Acari, Babesiosis, Glands, Theileria, Piroplasmida


Abstract An examination was made of Giemsa-stained microfilariae in thin blood films from dogs naturally or experimentally infected with Dirofilaria immitis or Dirofilaria repens. The blood was from 9 dogs infected with D. immitis and 9 dogs infected with D. repens. Measurements (total length, length of cephalic space, anterior end to nerve ring and last body nucleus, and nucleus-free tail tip) were made on 2 to 6 microfilariae from each dog using digitally captured images and imaging software. The microfilariae of D. repens were significantly (p<0.001) greater in all measured dimensions except for the length of the cephalic space which was significantly shorter (p<0.001) than that of D. immitis. The cephalic space of D. repens was characterized by being short and routinely being terminated by a distinct pair of nuclei that were separate from the remaining somatic nuclei of the microfilaria. The cephalic space of the smaller microfilaria of D. immitis is longer and does not have the distinct nuclei separated from the somatic column nuclei near the anterior end. The character of the cephalic space seems to be a criterion that could be routinely used for the easy differentiation of these two microfilariae in stained blood films.

Concepts: Function, Vector space, Units of measurement, IMAGE, Dog, Dirofilaria immitis, Dirofilaria, Microfilaria


Abstract Numerous myxozoan cysts (~1 mm) were found in the musculature of blackfin tuna (Thunnus atlanticus) harvested off the Caribbean island of St. Kitts. Myxospores were consistent with quadrate members of the Kudoidae, measuring 8.8 (8.2-9.4) µm wide, 7.3 (6.6-8.3) µm thick and 6.2 (5.8-6.9) µm long with 4 uniform drop-like polar capsules measuring 2.7 (2.2-3.2) µm long and 2.0 (1.7-2.2) µm wide. The 18S small-subunit (SSU) and 28S large-subunit (LSU) ribosomal DNA sequences did not result in direct matches to any published sequences. However, the SSU sequences (1,786 bp) obtained from 6 individual cysts were identical and demonstrated high homology to Kudoa thunni (99.0%) from albacore (Thunnus alalunga). Alternatively, 33 unique sequences were obtained for the LSU (~800 bp), demonstrating 0.1 to 5.0% variability between them, although a majority of these sequences (60%) demonstrated high homology (>99%) to K. thunni. Morphologically, the case isolate was smaller than published descriptions of K. thunni, however, rDNA sequence homology, and phylogenetic placement based on concatenated SSU and LSU rDNA sequences suggests this case isolate and K. thunni are conspecific. To our knowledge this is the first report of K. thunni infection in blackfin tuna from the Caribbean.

Concepts: Caribbean, Tuna, Thunnus, Scombridae, Yellowfin tuna, Saint Kitts, Albacore, Blackfin tuna


Abstract Two previously unrecognized species of the genus Hymenolepis are described based on specimens obtained from murid rodents Bullimus luzonicus, Apomys microdon and Rattus everetti collected on Luzon Island, Philippines. Hymenolepis bicauda n. sp. differs from all known Hymenolepis species in relative position of the poral dorsal and ventral osmoregulatory canals, gravid uterus occupying less than half the length of proglottid, relatively few eggs and the highly characteristic longitudinal split of proglottids at the end of the gravid strobila. Hymenolepis haukisalmii n. sp. differs from all known Hymenolepis species in the relative position of both poral and aporal dorsal and ventral osmoregulatory canals and uterus lacking dorsal and ventral diverticula. The shift in the relative position of the dorsal and ventral osmoregulatory canals was not known in Hymenolepis from rodents in other regions of the world and is reminiscent of the situation in Hymenolepis erinacei parasitic in hedgehogs and members of the genus Talpolepis parasitic in moles. The cosmopolitan species Hymenolepis diminuta was the only member of the genus previously reported from the Philippines.

Concepts: Rat, Philippines, Rodent, Mouse, Muridae, Muroidea, Manila, Luzon


Abstract Protozoans of the family Opalinidae are intestinal commensals in amphibians. To test the hypothesis that these organisms are susceptible to the antiprotozoal antibiotic metronidazole, we randomly assigned 60 juvenile Woodhouse toads (Bufo woodhousii) to receive a single oral dose of metronidazole or water. In pilot trials, the prevalence of opalinids in untreated members of this population was over 70%. One-third of the study population was dissected at each of 3 time points: 18 hr, 1wk, and 2 wk post-treatment. An examiner blinded to the toad’s treatment history determined the presence or absence of opalinids using a dissecting microscope. Opalinids were found in 3/10 toads in the treatment group and 9/10 in the control group after 18 hr (P < 0.02), none of the treatment group and 8/10 in the control group after 1 wk (P < 0.001), and none of the treatment group and 10/10 in the control group after 2 wk (P < 0.0001). These results suggest that a single-dose of metronidazole quickly and reliably clears opalinids from juvenile Woodhouse toads, with no evidence of short-term recurrence. The treatment was well tolerated, with no apparent morbidity and no mortality in either group. Future exploration of opalinid-related host fitness consequences may be facilitated by this simple method of developing a protozoan-free host population.

Concepts: Scientific method, Biology, Metronidazole, Social psychology, Amphibian, Toad, Opalina, Opalinidae


Abstract Examination of a small portion of the viscera of an oarfish recovered from Santa Catalina Island, southern California, revealed numerous tetraphyllidean tapeworm plerocercoids, Clistobothrium cf. montaukensis; 2 juvenile nematodes, Contracaecum sp.; and a fragment of an adult acanthocephalan, family Arhythmacanthidae. This suggests that the fish was relatively heavily parasitized. The presence of larval and juvenile worms suggests that oarfish are preyed upon by deep-swimming predators such as the shortfin mako shark, Isurus oxyrinchus, known to be a definitive host for the adult tapeworm, and also by diving mammals such as sperm whales, hosts of Contracaecum spp. nematodes.

Concepts: Southern California, Lamniformes, Lamnidae, Swordfish, Santa Catalina Island, California, Shortfin mako shark, Isurus, Longfin mako shark


Two new species of Staphylocystoides are described from masked shrews Sorex cinereus: Staphylocystis oligospinosus n. sp. was collected from the vicinity of Missoula, Montana, United States and Staphylocystoides parasphenomorphus n. sp. was collected from the vicinity of Whitehorse, Yukon Territory, Canada. Morphological differentiation from known species is provided. Both species are morphologically closest to Staphylocystoides sphenomorphus and to each other. Among other characters, Staphylocystoides oligospinosus n. sp. can be easily differentiated from all known species of the genus by unique cirrus armature which consists of a short zone of small spines at the base of the cirrus, a few large sparsely distributed spines of varying size in the middle part of the cirrus and hair-like microtriches densely covering the apical portion of the cirrus. Staphylocystoides parasphenomorphus n. sp. differs from S. oligospinosus n. sp. in a number of characters, most distinctly in cirrus armature, and from another morphologically similar species, S. sphenomorphus, in the number of proglottids, strobila size, number and size of rostellar hooks and relative length of cirrus sac. Comparison of partial sequences of nuclear large ribosomal RNA subunit gene (1310 bp) and mitochondrial NAD(P)H dehydrogenase subunit 1 gene (710 bp) strongly supports the status of the described forms as new species. This increases the number of Staphylocystoides species known in North America to 9 (5 parasitizing S. cinereus) and the total number of species in the genus to 12. Staphylocystoides parasphenomorphus n. sp. is the first named Staphylocystoides record in Canada.

Concepts: Gene, RNA, Ribosomal RNA, Ribosome, United States, Canada, North America, Sorex