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Seasonality has strong effects on natural systems by influencing resource availability, thereby interfering in plant–herbivore, prey–predator, and host–parasite interactions. We compared the seasonal structure of the helminth community of rufous-bellied thrushes (Turdus rufiventris), assessed its correlation with environmental variables, and interpreted temporal patterns of parasite abundance in relation to their life cycles and likely changes in the availability of intermediate hosts and vectors. Fifteen helminth species were found in a sample of 151 thrushes collected on a seasonal basis over 3 yr. Infracommunity structure was affected by season and year. The ordination of component communities grouped fall and winter samples within a gradient of similarity that was correlated with average relative air humidity (RH) and average ambient temperature. RH (alone or in combination with temperature, rainfall, or both) was also found to be a good predictor of the abundance of 5 helminth species.
Fish pathologists are often interested in which parasites would likely be present in a particular host. Parasite Co-occurrence Modeler (PaCo) is a tool for identifying a list of parasites known from fish species that are similar ecologically, phylogenetically, and geographically to the host of interest. PaCo uses data from FishBase (maximum length, growth rate, life span, age at maturity, trophic level, phylogeny, and biogeography) to estimate compatibility between a target host and parasite species–genera from the major helminth groups (Acanthocephala, Cestoda, Monogenea, Nematoda, and Trematoda). Users can include any combination of host attributes in a model. These unique features make PaCo an innovative tool for addressing both theoretical and applied questions in parasitology. In addition to predicting the occurrence of parasites, PaCo can be used to investigate how host characteristics shape parasite communities. To test the performance of the PaCo algorithm, we created 12,400 parasite lists by applying any possible combination of model parameters (248) to 50 fish hosts. We then measured the relative importance of each parameter by assessing their frequency in the best models for each host. Host phylogeny and host geography were identified as the most important factors, with both present in 88% of the best models. Habitat (64%) was identified in more than half of the best models. Among ecological parameters, trophic level (41%) was the most relevant while life span (34%), growth rate (32%), maximum length (28%), and age at maturity (20%) were less commonly linked to best models. PaCo is free to use at www.purl.oclc.org/fishpest.
The ixodid ticks parasitizing small-bodied nocturnal mouse and dwarf lemurs (Primates, Cheirogaleidae) in Madagascar are poorly documented. At Tsinjoarivo, a high-altitude eastern rain forest, mouse and dwarf lemurs were parasitized by ixodid ticks. At Ranomafana, a montane southeastern rain forest, dwarf lemurs hosted a species of Ixodes, whereas mouse lemurs were parasitized by Haemaphysalis lemuris. Ixodes specimens represent all active stages, and females are morphologically consistent with previous descriptions of Ixodes lemuris females, the only described stage in the literature. Morphological comparisons and genetic analysis using fragments of COI gene confirm that all Ixodes ticks from Tsinjoarivo and Ranomafana forests belong to the same species, i.e., Ixodes lemuris. Thus, we are able to provide descriptions of the previously unknown larva, nymph, and male. Mouse lemurs at both locations were parasitized only by immature stages of I. lemuris (at Tsinjoarivo) or H. lemuris (at Ranomafana), whereas dwarf lemurs were parasitized by all stages of I. lemuris. We suggest that ecological and biogeographical conditions may affect the pattern of tick infestation at Tsinjoarivo and Ranomafana. Additional studies are necessary to understand the tick-host associations of small-bodied nocturnal lemurs.
Molecular investigations of the ruminant response to ectoparasites at the parasite–host interface are critically dependent upon the quality of RNA. The complexity of ruminant skin decreases the capacity to obtain high quality RNA from biopsy samples, which directly affects the reliability of data produced by gene expression experiments. Two methods for isolating total RNA from skin were compared and the use of 4M guanidinium isothiocyanate (GITC) during frozen storage of the specimens was evaluated. In addition, the best procedure for RNA isolation from bovine skin punch biopsies was also tested on white-tailed deer skin biopsies. Skin biopsy punches were collected and frozen prior to pulverization for RNA isolation. Total RNA quantity and integrity were determined by spectrophotometry and capillary electrophoresis technology, respectively. Significantly increased total RNA yield (P < 0.05) and higher integrity (P < 0.05) were obtained with a TRI Reagent® isolation method. Freezing and subsequent storage of bovine skin punch biopsies in 4 M GITC did not affect the amount or integrity of total RNA recovered by either RNA isolation method. However, quantity and integrity of total RNA extracted with the TRI Reagent method were again significantly higher than with the alternate technique, confirming it as the superior method. The TRI Reagent isolation method also yielded high quality total RNA from white-tailed deer skin punch biopsies, suggesting the usefulness of this method for obtaining RNA of a quality suitable for gene expression studies in other ruminant species.
Female-biased sex ratio is a common phenomenon in parasites; however, the cause and consequence of the skewed sex ratio is less well known. Here, we studied the difference in sex ratio, a possible mechanism responsible for the development of unbalanced proportion of sexes and its consequences on sexual size dimorphism, between 3 louse species parasitizing the house sparrow Passer domesticus. Philopterus fringillae was more prevalent than Sturnidoecus refractariolus and Brueelia cyclothorax. As expected, the most common species, which was probably least affected by isolation and, hence, inbreeding, was characterized by a balanced sex ratio, whereas the 2 other species with low prevalence were significantly more female biased than expected on the basis of the local mate competition hypothesis. Further, in support of this notion, we found that P. fringillae infrapopulation size significantly, and positively, correlated with the sex ratio. Finally, we found significant differences in sexual dimorphism among the 3 louse species and, as expected, the relative size of males was smallest in species with a more female-biased sex ratio.
A survey of water mite larvae parasitizing adult mosquitoes was conducted throughout Pennsylvania. In total, 929,873 individuals and 46 species of mosquitoes were collected from 6,499 sites, and mites were examined from a subset of the parasitized mosquitoes. From 282 of the sites, 1,836 mosquitoes were parasitized by 4,769 mites, with a mean intensity of 2.6, ranging from 1 to 31. Twenty-one species of mosquitoes representing Aedes, Anopheles, Coquillettidia, Culex, Ochlerotatus, Orthopodomyia, and Psorophora were parasitized by 1 Parathyas sp., 7 Arrenurus spp., and 7 Arrenurus morphotypes. All mite species are documented from Pennsylvania for the first time. The largest numbers of hosts were Coquillettidia perturbans and Ochlerotatus trivittatus, and of parasites were Arrenurus danbyensis and Parathyas barbigera. Aedes spp., Ochlerotatus spp., and Psorophora ferox were mostly parasitized by P. barbigera, Anopheles spp. and Cq. perturbans mostly by Arrenurus spp., and Culex spp. by both P. barbigera and Arrenurus spp. Thirty-three different associations were observed, and 17 of these are new records. Parasitism of individual mosquitoes by more than 1 mite species was rare. Most P. barbigera individuals were attached on the pre-abdominal region of their hosts, and, when not in this position, they were attached anterior on the thorax, and less commonly on the cervix or abdomen. Most A. danbyensis and Arrenurus delawarensis individuals were attached to the cervix of Cq. perturbans. Arrenurus danbyensis on Cq. perturbans had mean and maximum intensities of 2.8 and 31, and showed a clear trend in attachment site distribution, with sequential progression from head to abdomen.
The molecular genetic variability of the 12S rRNA gene, on the basis of partial primary sequence and in silico-predicted secondary structures among Dermacentor reticulatus (Fabricius 1794) ticks, was studied in the Chernobyl Nuclear Power Plant (ChNPP) Exclusion Zone. In total, 20, 20, and 25 ethanol-preserved specimens, previously collected at 3 sites with 0.76, 1.91, and 4.5 millisievert (mSv)/hr ionizing radiation background, were examined. The primary sequence analysis generated 4 haplotypes defined by 3 polymorphic sites. The most common haplotype 1 was found in all 3 locations, representing 86.2% of all sampled individuals. Haplotype 4 (10.8%) was detected at the 1.91 and 4.50 mSv/hr sites. The unique haplotypes 2 (1.5%) and 3 (1.5%) were detected only at the 1.91 and 4.50 mSv/hr sites, respectively. The haplotype diversity, nucleotide diversity, and pairwise nucleotide differences for 2 tick populations at the 1.90 and 4.50 mSv/hr sites were 0.279, 0.00085, and 0.289, and 0.397, 0.00122, 0.413, respectively. No polymorphism was detected in ticks collected at the 0.76 mSv/hr site. The primary sequences of 12S rRNA were folded into the secondary structures and the free energy of haplotypes was calculated. The free energy at 37 C (ΔG) of the nonmutant haplotype 1 and the mutant haplotypes 2, 3, and 4 were −45.79, −44.17, −39.56, and −45.79 kcal/mol, respectively. Considering the correlation between the structural profile similarity of 12S rRNA and point mutations, haplotypes 1 and 4 have similar secondary structure profiles and have received a 0.999219 similarity score in the cluster tree. The unique haplotypes 2 and 3 have differences in the secondary structure in comparison with haplotypes 1 and 4; the similarity scores were 0.914747 and 0.169431, respectively. Further studies using more genetic markers are warranted to ascertain the genetic variability and population genetic structure within D. reticulatus tick populations in the ChNPP Exclusion Zone and to resolve their vector capacity.
Consumption of undercooked pork products is considered a major risk factor for contracting toxoplasmosis in humans in several countries. In total, 803 pork samples and 606 wild boar meat samples were collected from different regions of Latvia during June 2010 and February 2011 were tested for Toxoplasma gondii antibodies using an in-house ELISA assay. Seroprevalence in wild boar (33.2%, P < 0.05) was significantly higher than in domestic pig (4.2%). The prevalence of T. gondii–specific antibodies was greater in free-ranging domestic pigs (6.2%, P < 0.05) than those that were intensively farmed (0.4%). Animals from free-range farms had 17.6 times higher odds ratio (OR) (95% confidence interval [CI]: 2.4–129.8) for the presence of specific T. gondii antibodies than animals from intensive farms. The OR (95% CI: 1.1–2.7) of feral wild boars for T. gondii–specific antibodies was 1.7 times higher than for farmed wild boars. Our findings indicate that the prevalence of T. gondii infection was higher for animals with open access to wildlife and direct contact with environment. This is the first report of T. gondii prevalence in pigs in Latvia.
Felids are important in the epidemiology of Toxoplasma gondii infection because they are the only hosts that shed resistant oocysts in the environment. A total of 242 serum samples and 80 fecal samples from domestic cats in Latvia was tested for T. gondii infection. Serum samples were tested for T. gondii antibodies by an indirect in-house ELISA; antibodies were found in 125 (51.6%) of 242 cats; seroprevalence increased with age, indicating postnatal infection. Using multiple logistic regression analyses, age and outdoor access were found to be the most significant (F = 21.70, P < 0.05) factors associated with T. gondii infection in Latvia. Toxoplasma gondii-like oocysts were detected in 2 of the cats examined microscopically using the salt flotation method, but definitive diagnosis could not be made because a bioassay was not performed.
Unexplained and episodic die-offs of the dwarf surf clam, Mulinia lateralis, have been reported on the West Atlantic coast, with such an occurrence in South Carolina in June 2010. A sample of live clams from the 2010 South Carolina event was collected, and 200 clams were measured and necropsied. Two species of tapeworm larvae were observed. Plerocercoids (Duplicibothrium sp.) occupied the digestive gland ducts, and merocercoids (Rhodobothrium sp.) were found beneath the mantle. Specimens of both species were sequenced to obtain partial 28S rRNA gene sequences, and they were identified as the tetraphyllidean D. minutum and the rhinebothriidean R. paucitesticulare, based on an NCBI Standard Nucleotide BLAST search. Of the 200 clams, 2.1% were infected with merocercoids (mean intensity 1.3 ± 0.2) and 75% with plerocercoids (mean intensity 4.3 ± 3.7). Intensity of infection by plerocercoids increased significantly with individual shell length. The presence of plerocercoids was associated with enlargement of the digestive gland ducts, but no other pathology was observed. Because uninfected clams were abundant among the stranded molluscs, these parasites are not considered to be the causative agent of the die-off. This is a new host record for both elasmobranch tapeworms.
Cats are important in the epidemiology of Toxoplasma gondii because they are the only hosts that excrete environmentally resistant oocysts in feces. In the present study, hearts, serum, and feces from 36 feral cats from Addis Ababa area, Ethiopia, were examined for T. gondii infection. Antibodies to T. gondii were determined with the modified agglutination test (MAT, cutoff 1:25); 33 cats were seropositive. Hearts of all 36 cats were homogenized, digested in pepsin, and bioassayed in mice. Feces were examined for T. gondii oocysts by bioassay in mice. Viable T. gondii was isolated from heart of 26 by bioassay in mice and from 25 seropositive and 1 seronegative cats. Toxoplasma gondii was isolated from feces (oocysts) by bioassay in mice. In total, viable T. gondii was isolated from 27 of the 36 cats, and these isolates were designated TgCatEt1 to TgCatEt27. The high prevalence of T. gondii oocysts in feces of 8 (19.4%) of 36 cats is of high epidemiologic significance. This is the first report of isolation of viable T. gondii from any host in Ethiopia.
The lung fluke, Haematoloechus longiplexus, is the most prevalent and abundant parasite of introduced bullfrogs on Vancouver Island, British Columbia, Canada. The ecological success of this trematode in invasive bullfrogs is related to the fluke's ability to utilize native intermediate hosts for transmission. The purpose of this study was to identify the odonate (dragonfly/damselfly) species involved in the transmission of H. longiplexus to the introduced bullfrog. The prevalences and mean intensities of 21 species of odonates (nymphs and adults) were examined for metacercariae infections. Haematoloechus longiplexus is a second intermediate host specialist, being found only in damselflies. Six damselfly species exhibiting the “climber” ecological habit were identified as second intermediate hosts of H. longiplexus. Enallagma carunculatum (prevalence = 75.0%, mean intensity = 17.2 ± 10.8), Ischnura cervula (65.2%, 8.9 ± 4.3), Ischnura perparva (45.5%, 15.4 ± 10.3), and Enallagma boreale (40.7%, 4.8 ± 7.8) were the most commonly infected damselfly species. Metacercariae were absent in damselflies collected from sites lacking bullfrogs. Haematoloechus longiplexus was likely introduced along with the bullfrog, and subsequently adapted to the physid snail and diverse damselfly intermediate hosts present in ponds on Vancouver Island.
Visceral leishmaniasis (VL) is a disease that has both zoonotic and anthroponotic etiologies. In India, VL is endemic, considered to be anthroponotic, and caused by Leishmania donovani. Anthroponotic diseases are maintained by transmission from human to human and to a lesser extent from human to animals. Serum samples from 1,220 animals from 7 human VL endemic districts of Bihar, India, were tested for antibodies to a recombinant kinetoplast antigen (rK39 antigen) present in amastigotes of visceralizing Leishmania species, i.e., L. donovani complex. Additionally, PCR was used to examine samples positive by rK39 antigen serology. Antibodies to rK39 indicative of VL were detected in 33 of 1,220 animals. Thirty-one of 867 goats (Capra hircus), 1 of 161 cattle (Bos indicus), and 1 of 54 wild rats (Rattus sp.) were positive by rK39 serology. None of 106 chickens (Gallus domesticus), 26 sheep (Ovis aries), 3 water buffaloes (Bubalus bubalus), or 3 dogs (Canis familiaris) was positive by rK39 serology. Leishmania donovani DNA was detected by PCR in 20 rK39 positive blood samples from goats and 1 sample from a cow. The present study indicates that goats are potential animal reservoirs of human VL in India.
We analyzed proteins that were differentially expressed by 10-day-old schistosomula from 3 different hosts and determined that a functional thioredoxin peroxidase-2 gene has an important antioxidant role in Schistosoma japonicum, which we investigated further. A full-length cDNA encoding the S. japonicum thioredoxin peroxidase-2 (SjTPx-2) had an open reading frame of 681 bp that encoded 226 amino acids with a signal peptide of 24 amino acids. A cDNA encoding SjTPx-2 without the signal peptide sequence was isolated from 42-day-old schistosome cDNAs. Real-time quantitative RT-PCR analysis revealed that SjTPx-2 was upregulated in 7- and 13-day-old schistosomes, while the expression level in females was around 2-fold higher than that in male worms at 42 days. SjTPx was subcloned into pET28a( ) and expressed as both inclusion bodies and supernatant in Escherichia coli BL21 (DE3) cells. Western blotting showed that the recombinant SjTPx-2 (rSjTPx-2) was immunogenic. The purified recombinant protein could form disulfide-bonded dimers and it had peroxidase activity in vitro. An immunoprotection experiment in BALB/c mice showed that vaccination with recombinant SjTPx-2 could induce 31.2% and 34.0% reductions in the numbers of worms and eggs in the liver, respectively. This study suggests that SjTPx-2 may be an important antioxidative enzyme in scavenging ROS, and it may be a potential vaccine candidate or new drug target for schistosomiasis.
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.
We collected fecal samples from 9 dusky rice rats, Melanomys caliginosus (Rodentia, Cricetidae, Sigmodontinae), in a Biological Reserve in Costa Rica and found 8 (89%) to be infected with 2 Eimeria species which we describe here as new. Sporulated oocysts (n = 20) of the first, Eimeria melanomytis n. sp., are cylindroidal and measure 20.1 × 13.3 μm (18–23 × 13–15); micropyle and oocyst residuum are both absent, but a bilobular polar granule is present. Its sporocysts are ovoidal, 10.5 × 7.4 μm (10–13 × 6–8) with a small Stieda body, but both substieda and parastieda bodies are absent; a spheroidal sporocyst residuum is present, ∼5 μm wide. Sporulated oocysts (n = 20) of the second, Eimeria rebambensis n. sp., are subspheroidal, 21.2 × 17.0 μm (19–23 × 14–18); micropyle and oocyst residuum are both absent, but with a polar granule ∼2 μm wide. Sporocysts are elongate-ovoidal, 12.4 × 7.0 μm (11–14 × 6–9) with a distinct knob-like Stieda body, and a substieda body directly beneath it which is about twice as wide, but no parastieda body is present; the sporocyst residuum is an irregular mass composed of 8–10 globules scattered among the sporozoites, which are ∼10 × 5 μm, and have 1 refractile body at their wider end and a central nucleus. These are the first eimerians described from this rodent genus.
Morphological and molecular evidence suggest that specimens formerly described as Lacunovermis sp. from Nacella (Patinigera) spp. (Patellogastropoda: Patellidae) belong to a new species of GymnophalloidesFujita, 1925. Based on the new information, they are identified as Gymnophalloides nacellae n. sp. The new species differs from Gymnophalloides tokiensis, Gymnophalloides seoi, and Gymnophalloides heardi mainly through the presence of a group of papillae located on the ventral surface between oral and ventral suckers. A detailed morphological study revealed the lack of pars prostatica, a character previously reported in G. seoi, which is why it was formerly placed in the Gymnophallinae. Molecular information proved that G. nacellae is close to G. seoi, being nestled together with Parvatrema representatives. This molecular information, along with the absence of pars prostatica, allows these 2 genera to be placed in Parvatrematinae. An amended diagnosis of Gymnophalloides is provided. Histological sections of mantle epithelium of the limpet show metacercariae attached by their oral and ventral suckers in a similar manner to G. seoi in its host, the oyster Crassostrea gigas. Tissue reaction includes cells of outer mantle epithelium being stretched by sucker attachment, hemocyte infiltration of connective tissue between mantle epitheliums, and abnormal calcareous deposition on the inner surface of the shell.
Homalometron palmeri n. sp. is described and reported from the following fishes in the northern Gulf of Mexico: Micropogonias undulatus, Sciaenops ocellatus, Bairdiella chrysoura, Pogonias cromis, Fundulus grandis, Fundulus similis, and Eucinostomus argenteus. This species historically has been misidentified as Homalometron pallidum by some, and treated as Homalometron sp. by others. The new species differs from H. manteri by having a smaller body size, relatively longer postcecal space ranging from 7 to 15% of body length compared with 6–8%, body spines from 12 to 17 μm long compared with 15–20 μm, and an oral-to-ventral sucker width ratio of 1:1.2–1.3 compared with 1:1.3–1.5. Ribosomal DNA sequences from H. palmeri n. sp., H. pallidum, Homalometron manteri, and Homalometron pseudopallidum are compared and the new species is found to be most similar to H. manteri, a sympatric species. Comparison between 2 mitochondrial genes from H. palmeri n. sp. and H. manteri provided further evidence for their status as distinct species. Pairwise comparison of 503 aligned bases from ND1 gene revealed 33 variable sites (6.5%) between the 2 species. Pairwise comparison of 1,152 aligned bases from COI gene revealed 73 variable sites (6.3%) between the 2 species. Interspecific variability in mitochondrial sequences between the 2 species was 3–16 times greater than intraspecific variability in either species.
Myxobolus stanlii sp. n. was described from largescale stonerollers (Campostoma oligolepis) from the Mobile River Basin in Alabama. The parasite was described using critical identifying morphological features, and the 18S small subunit ribosomal RNA (SSU rRNA) gene sequence. The spore body was ovoid, 10.03 ± 0.7 (7.5–11.0) μm long and 8.8 ± 1.5 (6.3–11.3) μm wide in frontal view. Spore thickness was 6.3 ± 2.7 (6.2–8.6) μm in sutural view. Polar capsules were pyriform, of equal size, and oriented in plane with the sutural ridge. Polar capsules were 2.45 ± 1.5 (range 2.1–4.3) μm in width and 4.6 ± 2.7 (range 4.5–6.9) μm in length. Based on the SSU rRNA gene sequence of Myxobolus stanlii sp. n. is most closely related to M. pseudodispar.
Haemoproteus anatolicum n. sp. was identified in the tortoise Testudo graeca. The new species is described based on the morphology of its blood stages and a segment of the mitochondrial cytochrome b gene, which can be used for molecular identification and diagnosis. Chelonian haemoproteids recorded in the past were defined solely on the basis of their morphological characteristics. The chelonian haemoproteid we describe as a new species has a close genetic relationship to lizard haemoproteids, i.e., Haemoproteus ptyodactylii and Haemoproteus kopki. The new species description provides significant new information for little-known chelonian haemoproteids.
This study presents a new record for the occurrence of larval Ortleppascaris sp.(Sprent, 1978). The nematodes were collected from inside fibrous cysts found in the livers of cane toads, Rhinella marina (Linnaeus, 1758), captured in eastern Brazilian Amazonia. This is the first record of Ortleppascaris sp. larvae in both Brazil and this amphibian host, increasing its distribution in South America as well as expanding the number of helminths known to infect this toad. The detailed description of Ortleppascaris sp. provides new taxonomic data for these larvae, as well as sequences of the internal transcribed spacers and small subunit DNA segments, and the cytochrome oxidase I gene, which will, in time, contribute to a better understanding of the phylogeny of this group of parasites.
Increasingly frequent outbreaks of zoonotic infections call for studies of wildlife parasites to reach a better understanding of the mechanisms of host switch, leading to the evolution of new diseases. However, speciation processes have been insufficiently addressed in experimental parasitology studies, primarily due to difficulties in determining and measuring mate-recognition signals in parasites. We investigated patterns of sexual process and ookinete development in avian Haemoproteus (Parahaemoproteus) spp. (Haemosporida, Haemoproteidae) using in vitro experiments on between-lineage hybridization. Eleven mitochondrial cytochrome b (cyt b) lineages belonging to 9 species of hemoproteid were isolated from naturally infected passerine birds. The parasites were identified to species on the basis of morphology of their gametocytes and polymerase chain reaction amplification of segments of the cyt b gene. Sexual process and ookinete development were initiated in vitro by mixing blood containing mature gametocytes with a 3.7% solution of sodium citrate and exposing the mixture to air. Ookinetes of all lineages except Haemoproteus payevskyi (lineage hRW1) and Haemoproteus nucleocondensus (hGRW1) developed; the 2 latter species did not exflagellate. Between-lineage hybridization was initiated by mixing blood containing mature gametocytes of 2 different parasites; the following experiments were performed: (1) Haemoproteus pallidus (lineage hPFC1) × Haemoproteus minutus (lineage hTURDUS2); (2) H. pallidus (hPFC1) × Haemoproteus tartakovskyi (hSISKIN1); (3) Haemoproteus belopolskyi (hHIICT3) × Haemoproteus lanii (hRB1); (4) Haemoproteus balmorali (hSFC1) × H. pallidus (hPFC1); (5) H. belopolskyi (hHIICT1) × Haemoproteus parabelopolskyi (hSYBOR1); (6) H. tartakovskyi (hHAWF1) × H. tartakovskyi (hSISKIN1); (7) H. pallidus (hPFC1) × H. lanii (hRB1); (8) H. tartakovskyi (hHAWF1) × H. parabelopolskyi (hSYBOR1). We report 4 patterns of between-lineage interactions that seem to be common and might prevent mixing lineages during simultaneous sexual process in wildlife: (1) the blockage of ookinete development of both parasites; (2) the development of ookinetes of 1 parasite and blockage of ookinete development of the other; (3) selective within-lineage mating resulting in ookinete development of both parent species and absence of hybrid organisms; (4) absence of selective within-lineage mating resulting in presence of ookinetes of both parents and also development of hybrid organisms with unclear potential for further sporogony. The present study indicates directions for collection of source material in the investigation of mechanisms of reproductive isolation leading to speciation in these parasites. The next steps in these studies should be the development of nuclear markers for distinguishing hemosporidian hybrid organisms and the experimental observation of further development of hybrid ookinetes in vectors.
The nematodes Eustrongylides spp. collected from different fish species in China were examined for their intra- and interspecific evolutionary variations using the molecular markers mitochondrial cytochrome oxidase c subunit 1 (COI) gene and internal transcribed spacer (ITS) rDNA regions. The phylogenetic analysis indicated that Eustrongylides species are divided into 3 well-supported clades. The ITS divergence between the clades suggested that clades 2 and 3 might represent the same species, whereas clade 1 represent another cryptic species. The host specificity of these nematodes was analyzed according to prevalence data, host range, and phylogenetic information. Clade 1 was found in 4 fish species, i.e., Odontobutis obscurus, Silurus asotus, Culter mongolicus, and Acanthogobius flavimanus, but was predominant in the 2 perciform species, O. obscurus and A. flavimanus. Clade 2 was found in 3 fish species, Monopterus albus, Channa argus, and Channa asiatica, but was predominant in M. albus, reported to feed primarily on oligochaetes, the first intermediate host of Eustrongylides sp. Clade 3 was found in 9 species, but its low prevalence suggests accidental infection in all species. Although the larval nematode presented low host specificity, it exhibited some host preference.
Visceral leishmaniasis, a vector-borne disease caused by Leishmania donovani and Leishmania infantum, currently affects 12 million individuals in 88 countries. In the present study, a real-time PCR (rt-PCR) assay has been optimized and validated against 2 other routine methods, i.e., microscopy and limiting dilution culture assay, to estimate parasite load in the liver of infected Syrian hamsters (Mesocricetus auratus). A set of specific primers amplified a 116-bp target template of the kinetoplastid DNA of L. donovani in a SYBR® Green-based rt-PCR assay. To assess the methods, we tested 2 anti-leishmanial compounds belonging to the class of arylimidamides, DB745 (2,5-bis[2-ethoxy-4-(2-pyridylimino)aminophenyl]furan) and DB766 (2,5-bis[2-(2-propoxy)-4-(2-pyridylimino)aminophenyl]furan) for efficacy in vivo in Syrian hamsters infected with L. donovani promastigotes. Parasite load was quantified in liver by all 3 methods and was found comparable. Of the 3 methods, rt-PCR was the fastest and most convenient, sensitive, and reproducible method.
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.
Encephalitozoon cuniculi is an obligate intracellular microsporidian parasite that can result in clinical and subclinical infection in many species. It is also considered the cause of a potential zoonotic disease. In the present study, a serological survey was conducted using samples from pet dogs in the state of Florida. Twenty-seven of 125 serum samples, or 21.6%, were found to demonstrate reactivity by ELISA, with titers ranging from 1:32 to 1:512. There were no significant differences by age or sex. This is the first report on the detection of E. cuniculi antibodies in dogs in the United States.
Parasite distributions fundamentally depend on the distributions of their hosts but may be more restricted than their hosts. Host–parasite symbioses tend to be spatially aggregated, and widely distributed host–parasite relationships are rare. Here, we combine field observations with published collection data to document the current known distribution of the nematode, Myrmeconema neotropicum, which infects the Neotropical canopy ant Cephalotes atratus. We report 6 new records from different Brazilian ecosystems, bringing the total number of independent observations of this interaction to 11. The broad distribution of these data points suggests that M. neotropicum infects C. atratus throughout its geographic range, although possible disturbance effects and specific habitat associations of the interaction remain unknown.
Toxoplasma gondii infections are common in humans and other animals, but clinical disease is relatively rare. It is unknown whether the severity of toxoplasmosis in immunocompetent hosts is due to the parasite strain, host variability, or to other factors. Recently, attention has been focused on the genetic variability among T. gondii isolates from apparently healthy and sick hosts. Whether T. gondii genetic makeup plays a part in the pathogenesis of clinical feline toxoplasmosis is uncertain because little is known of genetic typing of strains associated with clinical feline toxoplasmosis. A 6-mo-old domestic male cat was hospitalized because of lethargy, anorexia, fever, and diarrhea. Numerous (6 million in 1 sample) T. gondii oocysts were found in feces of the cat and antibodies to T. gondii (titer 1:800) were found in its serum by the modified agglutination test. The cat was medicated orally with Clindamycin for 10 days; it became asymptomatic after 10 days and was discharged from the hospital. Viable T. gondii (designated TgCatUs9) was isolated from feces (oocysts) by bioassays in mice. Genetic typing using the DNA extracted from the brains of infected mice and 10 PCR-restriction fragment length polymorphism (RFLP) markers revealed Type II allele at the SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, and PK1 loci and Type I at the L358 and Apico loci; therefore, this isolate belongs to the ToxoDB PCR-RFLP genotype no. 4, which is grouped into the Type 12 lineage that is dominant in wildlife from North America. To our knowledge, this is the first T. gondii isolate characterized genetically from a sick cat in the USA.
Serum samples from 197 clinically healthy dogs residing in the Banat Region, the western historical part of Romania, were assayed by an indirect fluorescent antibody test for the presence of anti-Babesia canis antibodies. Overall, the seroprevalence was 19.8% (39/197). The percent of seropositive dogs in rural areas (28.4%; 19/67) was significantly higher (P < 0.05) compared to dogs living in urban areas (15.4%; 20/130). Seroprevalence of B. canis infection in hunting dogs was also found to be significantly higher (P < 0.05) compared to canines with other lifestyles, but no significant difference was found between companion and kennel dogs. The statistical analysis showed that no significant differences (P > 0.05) were present between the seroprevalence of infected animals associated with age, gender, or breed. The hunting lifestyle was the only factor (OR = 4.57; 95% CI = 2.1–10.2; P = 0.002) positively associated with seroprevalence in dogs and can be considered the risk factor in the acquisition of infection. Also, the results of the present survey indicate that infection with B. canis in dogs is common in the sampling area and that it is an important pathogen for the local canine population.
The purpose of this study was to verify the in vitro development of Trypanosoma sp. isolated from Leptodactylus ocellatus frogs under a new protocol using a biphasic medium composed of Novy, McNeal, and Nicolle (NNN) blood agar medium as a solid phase and liver infusion, brain heart infusion, and tryptose (LIBHIT) medium as a liquid phase. Blood forms, collected by cardiac puncture or after the maceration of different organs, were inoculated in culture tubes containing the biphasic medium composed by NNN and LIBHIT. Trypanosomes were observed 4 days postinoculation; most bloodstream trypomastigotes had differentiated into epimastigotes and amastigotes by this time. Trypomastigotes were again observed in older cultures (7 days). Parasites were successfully subcultured for 8 mo in this medium and successfully cryopreserved. The present study provides a new protocol medium for the isolation and culture of anuran trypanosomes.
This report describes a novel assay for the detection of gastrointestinal anthelmintics using mice infected with Haemonchus contortus and adapted to the 1 animal/test group protocol. Mice infected with both H. contortus and Heligmosomoides polygyrus were fed ivermectin-medicated diets for 6 days. A dietary level of 0.09375 ppm was 98.1% effective against the 0- to 6-day-old abomasal stomach worm of sheep, whereas a level of 0.75 ppm reduced the 3- to 9-day-old H. polygyrus worm burden by 94.0%. H. contortus was approximately 8-fold more sensitive to ivermectin than was H. polygyrus in this model. The sensitivity of this assay rivals that of the gerbil-Trichostrongylus colubriformis model while utilizing a more economical host.
Leishmaniasis is an insect-transmitted parasitic disease with a worldwide distribution. Leishmania spp. infections cause a broad spectrum of clinical signs, ranging from skin lesions to fatal visceral disease. Dogs are a major reservoir host for visceral leishmaniasis in humans. While the disease is endemic in the Middle East and North Africa, little is known concerning canine Leishmania spp. infections in Egypt. Accordingly, blood samples were collected from 50 stray dogs in Giza, Egypt. Canine sera were tested for antibodies to visceralizing Leishmania spp. by commercial immunochromatographic strip assays based on recombinant antigen K39. Antibodies to Leishmania spp. were found in 5 of 50 (10%) of dogs tested from Egypt. Results from this study indicate that stray dogs are exposed to visceralizing Leishmania species in Egypt.
Toxoplasma gondii infection was studied in Khon Kaen, northeastern Thailand. Blood specimens were collected from 493 non-pregnant women between 2009 and 2012. Presence of antibodies to T. gondii was determined using the latex agglutination test (cutoff titer 1:32). Thirteen of 493 (2.6%) were found to be seropositive for T. gondii infection. There was no age dependence in the prevalence. The present study reporting a low prevalence of T. gondii infection in northeastern Thailand suggests that the traditional lifestyles and climatic environments may limit the emergence of toxoplasmosis in this region.
There is a lack of information regarding the prevalence of Toxoplasma gondii infection in sheep from northeastern China. In the present study, serum samples from 566 domestic sheep were collected from Liaoning Province, northeastern China, to investigate the prevalence of T. gondii antibodies using an indirect hemagglutination antibody test. Twenty-five of 566 samples (4.4%) were seropositive at the cutoff of 1:64 serum dilution. No difference was found among 6 geographic regions (P > 0.05). This is the first report of T. gondii infection in sheep in Liaoning Province.
In recent years, surveys of Toxoplasma gondii infection in dogs have been reported throughout the world, including China. However, information is lacking regarding the prevalence of T. gondii infection in pet dogs in northeastern China. In the present study, we report the seroprevalence of T. gondii in pet dogs in Shenyang, northeastern China. Sera samples from 328 pet dogs in 5 districts were examined for T. gondii antibodies with an indirect hemagglutination antibody (IHA) test; 10.0% tested seropositive. There were no significant differences in terms of sex, age, and locality (P > 0.05). The results indicate that infection by T. gondii is widely prevalent in pet dogs in Shenyang, northeastern China, which has potential implications for public health in this area.
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