Vermamoeba vermiformis in hospital network: a benefit for Aeromonas hydrophila Abstract Aeromonas hydrophila, considered as an emerging pathogen, is increasingly involved in opportunistic human infections. This bacterium, mainly present in aquatic environments, can therefore develop relationships with the free-living amoeba Vermamoeba vermiformis in hospital water networks. We showed in this study that the joint presence of V. vermiformis and A. hydrophila led to an increased bacterial growth in the first 48 h of contact and moreover to the protection of the bacteria in adverse conditions even after 28 days. These results highlight the fact that strategies should be implemented to control the development of FLA in hospital water systems.

A new species Myxodavisia jejuensis n. sp. (Myxosporea: Sinuolineidae) isolated from cultured olive flounder Paralichthys olivaceus in South Korea Abstract A new myxosporean parasite, Myxodavisia jejuensis n. sp. (Myxozoa; Bivalvulida) is described from the urinary bladder of olive flounder Paralichthys olivaceus cultured on Jeju Island, Korea. Two long lateral appendages with whip-like extensions were attached to mature spores of triangular to semi-circular shape. The spores were measured at 13.1 ± 1.1 μm in length, 17.2 ± 1.0 μm in thickness, and 13.1 ± 1.0 μm in width. Two spherical polar capsules, with a diameter of 5.0 ± 0.4 μm, were observed on opposite sides in the middle of the spore. The suture line was straight or slightly sinuous on the middle of spores. The 18S rDNA from M. jejuensis n. sp. was used in BLAST and molecular phylogenetic analysis. The results demonstrated that M. jejuensis n. sp. was closest to Sinuolinea capsularis and that the infection site tropism was correlated with the phylogeny of marine myxosporeans. In addition, we designed specific primers to detect the 18S rDNA gene of M. jejuensis n. sp.; the results showed specific amplification in M. jejuensis n. sp. among the myxosporeans isolated from the urinary bladder of the cultured olive flounder.

Identification of adaptive inhibitors of Cryptosporidium parvum fatty acyl-coenzyme A synthetase isoforms by virtual screening Abstract Cryptosporidiosis is a significant cause of gastroenteritis in both humans and livestock in developing countries. The only FDA-approved drug available against the same is nitazoxanide, with questionable efficacy in malnourished children and immunocompromised patients. Recent in vitro studies have indicated the viability of Triacsin C as a potential drug candidate, which targets the parasite’s long-chain fatty acyl coenzyme A synthetase enzyme (LC-FACS), a critical component of the fatty acid metabolism pathway. We have used this molecule as a baseline to propose more potent versions thereof. We have applied a combined approach of substructure replacement, literature search, and database screening to come up with 514 analogs of Triacsin C. A virtual screening protocol was carried out which lead us to identify a potential hit compound. This was further subjected to a 100-ns molecular dynamics simulation in complex to determine its stability and binding characteristics. After which, the ADME/tox properties were predicted to assess its viability as a drug. The molecule R134 was identified as the best hit due to its highest average binding affinity, stability in complex when subjected to MD simulations, and reasonable predicted ADMET (Absorption, Distribution, Metabolism, Excretion and Toxicity) properties comparable to those of the Triacsin C parent molecule. We have proposed R134 as a putative drug candidate against the Cryptosporidium parvum LC-FACS enzyme isoforms, following an in silico protocol. We hope the results will be helpful when planning future in vitro experiments for identifying drugs against Cryptosporidium.

Identification of volatile biomarkers of Giardia duodenalis infection in children with persistent diarrhoea Abstract Currently, chronic diarrhoea syndrome in children is a very common pathology whose aetiology is sometimes difficult to identify. Methodologies for the diagnosis of infections have diversified, and gas chromatography/mass spectrometry (GC/MS) is a very useful tool. The aim of this study was to identify volatile biomarkers of the presence of Giardia duodenalis in the faeces of patients with chronic diarrhoea (with and without giardiasis) using static headspace extraction followed by GC/MS. The analysis of the volatiles extracted from the headspace had enough sensitivity to detect differences in the volatile profiles in the faeces of the patients with and without Giardia duodenalis infection and discriminate between them. Dimethyl disulphide and trisulphide were found in the faeces of patients without giardiasis but not in the faeces of patients with G. duodenalis. Finally, three possible biomarkers, acetic acid, 1,4-dimethoxy-2,3-butanediol and 1,3-dimethoxy-2-propanol, were proposed to identify patients with giardiasis; these compounds were not present in the patients without the parasite. Multivariate analysis revealed that principal component 1 separated the stool samples according to the presence of infection by G. duodenalis despite the inter-individual variability in biological specimens such as faeces.

Oral inoculation of ultraviolet-irradiated Eimeria species oocysts protects chickens against coccidiosis Abstract Prevention of coccidiosis is one of the best ways of controlling disease. Therefore, the present study was carried out to evaluate the protective effect of ultraviolet (UV)-irradiated sporulated oocysts of Eimeria species against coccidiosis in layer chickens. One hundred forty-four one-day-old layer chicks were randomly divided into 4 groups (n = 36), including non-immunized/non-challenged negative control group (NC group), non-immunized/challenged control group (NIC group), non-irradiated sporulated oocyst/challenged group (CA group), and UV-irradiated sporulated oocyst/challenged (UV group). At the age of 4 days, chickens in groups UV and CA were both orally inoculated with 1.0 × 104 UV-irradiated and non-irradiated sporulated oocysts of Eimeria species, respectively. Chickens in groups NIC and NC were served as positive and negative controls, respectively. Chickens in all groups were orally challenged with 7.5 × 104 sporulated oocysts of Eimeria species except the NC group at the age of 21 days. The results revealed that chicks receiving UV-irradiated sporulated oocysts had no signs of illness with minimal or no changes in the cecal integrity and a significantly lower oocyst shedding (OPG) than in the NIC group. Additionally, the cytokine gene expression profiles were evaluated. Expression levels of IL-2, IL-12, and IFN-γ were significantly higher in the spleen of chicks in the UV and CA groups than in the NC group post-challenge. As expected, treatment with irradiated oocysts resulted in a significant reduction in oocyst shedding and maintenance of cecal mucosal integrity. Furthermore, the body weight was higher in chickens inoculated with UV-irradiated oocysts than their non-irradiated counterparts. In conclusion, our results demonstrate that inoculation with UV-irradiated sporulated oocysts of Eimeria species can produce a substantial reduction in infection symptoms.

The intermediate hosts of Wardium cirrosa (Krabbe, 1869) Spassky, 1961 (Cestoda, Cyclophyllidea, Aploparaksidae) in Ukraine Abstract The metacestodes of aploparaksid cestode Wardium cirrosa Krabbe, 1869 parasitic in gulls were found in polychaetes of the family Nereidae collected off the Black Sea coast, Ukraine. Two species of polychaetes, Hediste diversicolor (prevalence 5.3%; intensity 1–3 specimens) and Neanthes succinea (prevalence 9.9%; intensity 1–39 specimens), were infected with cysticercoids that were observed either individually or in accumulations. The preliminary identification of the material based on morphological characteristics was later confirmed by experimental infection of the definitive host, Larus cachinnans (Charadriiformes: Laridae) with metacestodes, and by the identity of the partial 28S rDNA sequences of cysticercoids and experimentally obtained adults. Although previous studies suggested freshwater leeches as the intermediate host for W. cirrosa, our study provides the evidence for marine polychaetes to serve as intermediate hosts. This study is the first to present the morphological characteristics of metacestodes of W. cirrosa in addition to molecular data for this species, as well as reporting the possibility of several cysticercoids developing from a single oncosphere. Morphology of the adult specimens obtained in the experiment was compared with adults of W. cirrosa previously collected from L. cachinnans in Ukraine. The results of our study suggest that further research focused on the elucidation of the life cycles of cestodes within the genus Wardium should consider marine invertebrates as potential intermediate hosts.

Ultrastructural changes in hydatid cyst walls obtained from human cases, exposed to different therapeutic approaches Abstract Recurrence of cystic echinococcosis as a result of treatment failure is frequently reported to cause a major problem in management of such serious parasitic infection. The deeply seated innermost germinal layer of hydatid cysts is a relatively delicate layer, yet responsible for viability maintenance of this parasitic stage. In this study, a trial was done to explore the ultrastructural changes in germinal and laminated layer of the hydatid cyst for the first time in human cases exposed to different therapeutic approaches which were done earlier to the final open surgical intervention. Four groups were included: group 1 did not receive any earlier form of treatment; group 2 was previously treated with only medical therapy; group 3 was treated with a single course of medical treatment, plus a single PAIR technique; group 4 was treated with multiple courses of medical treatment plus multiple PAIR techniques. Complete alteration of ultrastructural features of germinal and laminated layers were observed only with samples from group 4, indicating a kind of failure of the therapeutic approaches used in group, 1, 2, and 3, unless repeated in group 4 to achieve a real change regarding the fitness of the parasitic cystic lesions. Searching for more effective, safe, therapeutic method is highly recommended which may end the suffering of the affected patients.

Diversity of Empruthotrema Johnston and Tiegs, 1992 parasitizing batoids (Chondrichthyes: Rajiformes and Myliobatiformes) from the Southwest Atlantic Ocean, with description of three new species Abstract During an extensive research project involving 519 specimens of batoids, including 13 species of Rajiformes and Myliobatiformes (Chondrichthyes) from the Argentine Sea, three new species of Empruthotrema were found and are described using morphologic characteristics and two molecular markers: LSU rDNA and COI mtDNA. The new species can be distinguished from their congeners by the number and distribution of the marginal loculi, the length and morphology of male copulatory organ, and the presence of eyespots. Additionally, multivariate analysis identified the dimensions of the pharynx and ejaculatory bulb as diagnostic features. Host specificity and previous records of the genus in the region are discussed. This is the first description of new species in this genus for the Southwestern Atlantic Ocean, as well as for arhynchobatid hosts.

Detection of “ Candidatus Rickettsia wissemanii ” in ticks parasitizing bats (Mammalia: Chiroptera) in the northern Brazilian Amazon Abstract A total of 482 bats representing 32 species and two families were captured in the Amazon forests of the Amapá state in northern Brazil. Nineteen Artibeus planirostris bats (3.9 %) were infested with 160 ticks, all identified as Ornithodoros hasei. Three pools of larvae were screened for rickettsial DNA via polymerase chain reaction (PCR) targeting three rickettsial genes: gltA, ompA and htrA. Only one of them yielded an amplicons of the expected size for all three molecular assays. Comparisons of the obtained sequences including a phylogenetic analysis confirmed the occurrence of “Candidatus Rickettsia wissemanii” in Brazil.

Long-term temporal variation in the parasite community structure of metazoans of Pimelodus blochii (Pimelodidae), a catfish from the Brazilian Amazon Abstract The Amazon represents one of the most complex biomes in the world; however, the temporal variations in parasite community structure of fishes inhabiting this region remain poorly understood. Therefore, processes generating such variations are still unknown. The present study evaluated the long-term temporal variation of community structure of metazoan parasites of Pimelodus blochii collected in Iaco River, State of Acre (Southwestern Brazilian Amazon). A total of 196 parasites were collected over a 6-year period (2012–2017). Twenty-four different taxa of parasites were found, of which 5 Monogenea, 11 Nematoda, 3 Digenea, 1 Acanthocephala, 1 Cestoda, and 3 Crustacea. The overall species richness ranged from 4 in 2012 to 17 in 2016, in which nematodes (larvae and adults) showed higher numerical dominance, diversity, and species richness. However, the annual species richness was similar between the study years, except in 2016, where it showed a distinctly higher value. The overall parasite diversity was also different in 2012 and 2016, whereas the overall abundance differed in 2013 and 2017. The prevalence and abundance of some infracommunities of parasites varied over time. The temporal changes in the parasite community structure of P. blochii are probably related to variations in host-related features, i.e., body size and shift in diet composition as well as to the occurrence of parasites with distinct life history and biology (mainly monogeneans, digeneans, and nematodes). This is the first evaluation of a long-term temporal variation in the structure of the parasite community in fish from the Amazon.