SciCombinator

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Journal: Veterinary parasitology

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Echinostomiasis is a food-borne, intestinal, zoonotic, snail-mediated helminthiasis caused by digenean trematodes of the family Echinostomatidae with seven species of the genus Echinostoma infecting humans or domestic and wildlife animals. Echinostoma paraensei is a peristomic 37-collar-spined echinostome belonging to the “revolutum group”. Praziquantel (PZQ) is the drug of choice for treatment and control of human schistosomiasis and food-borne trematodiasis. In the present study we used scanning and transmission electron microscopy to further elucidate the trematocidal effect of PZQ on adult E. paraensei and confirmed that this trematode is a suitable model to study anthelmintic drugs. Hamsters infected with E. paraensei were treated with a single dose of 30mgkg(-1) of PZQ. The worms were recovered 15, 30, 90 and 180min after drug administration. There was a significant decrease in worm burden in the small intestine in the hamster-E. paraensei model at the intervals of 30, 90 and 180min after the treatment. The worms displayed damage of the peristomic collar with internalization of the spines and erosion of the tegument of the circumoral head-collar of spines. Ultrastructural analysis demonstrated an intense vacuolization of the tegument, appearance of autophagic vacuoles and swelling of the basal infolds of the tegumental syncytium. There was no change in the morphology of cells from the excretory system of adult E. paraensei, however, there was an apparent decrease of stores of glycogen particles in parenchymal cells in PZQ-treated worms. Our results demonstrated that PZQ promotes surface and ultrastructural damage of the tegument of adult E. paraensei supporting the idea that this trematode may constitute a good model to investigate drug effects mechanisms in vitro and in vivo.

Concepts: Electron, In vivo, Digenea, Praziquantel, In vitro, Trematoda, Anthelmintic, Emodepside

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The objective of this study was to assess the interleukin 10 (IL-10) concentrations in the sera of dogs suffering from demodicosis.

Concepts: Interleukin, Dog, Demodex, Demodex canis

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In Maio Island, Republic of Cape Verde, a seven-year old mongrel female dog exhibiting severe generalized adenomegaly and a poor body condition was examined during an animal welfare campaign. A blood smear was drawn from peripheral blood collection and several organisms consistent with Dirofilaria immitis microfilariae were identified. Both the antigen test conducted from plasma and the RT-PCR test performed from the blood smear sample were positive for D. immitis. This is, to the best of our knowledge, the first report of D. immitis in Cape Verde. The fact that the dog was autochthonous and had never left the island strongly suggests there might be other animals infected with the parasite. Our finding confirms the existence of the parasite in the canine population and necessarily implies the presence of a competent vector. As a serious cardiopulmonary disease and with the risk of the pathogen spreading rapidly, broader epidemiological studies need to be conducted to determine D. immitis prevalence in the canine population of Maio Island.

Concepts: Immune system, Epidemiology, Bacteria, Blood, Biology, Hematology, Cape Verde, Dirofilaria immitis

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During the last 50 years human anisakiasis has been rising while parasites have increased their prevalence at determined fisheries becoming an emergent major public health problem. Although artificial enzymatic digestion procedure by CODEX (STAN 244-2004: standard for salted Atlantic herring and salted sprat) is the recommended protocol for anisakids inspection, no international agreement has been achieved in veterinary and scientific digestion protocols to regulate this growing source of biological hazard in fish products. The aim of this work was to optimize the current artificial digestion protocol by CODEX with the purpose of offering a faster, more useful and safer procedure for factories workers, than the current one for anisakids detection. To achieve these objectives, the existing pepsin chemicals and the conditions of the digestion method were evaluated and assayed in fresh and frozen samples, both in lean and fatty fish species. Results showed that the new digestion procedure considerably reduces the assay time, and it is more handy and efficient (the quantity of the resulting residue was considerably lower after less time) than the widely used CODEX procedure. In conclusion, the new digestion method herein proposed based on liquid pepsin format is an accurate reproducible and user-friendly off-site tool, that can be useful in the implementation of screening programs for the prevention of human anisakiasis (and associated gastroallergic disorders) due to the consumption of raw or undercooked contaminated seafood products.

Concepts: Scientific method, Biology, Fish, Object-oriented programming, Seafood, Herring, Pepsin, Clupeidae

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Culicoides (Diptera: Ceratopogonidae) are biological vectors of bluetongue virus (BTV). Bluetongue is a viral disease that affects domestic and wild ruminants. Since its recent emergence in northern Europe, this disease has caused considerable economic losses to the sheep and cattle industry. The biotopes, and more particularly the chemical characteristics which are suitable for larval development of the main vector species, are still relatively unknown. This study shows that the larvae of biting midges belonging to the species Culicoides obsoletus and Culicoides scoticus are able to breed in different types of silage residue (maize, grass, sugar beet pulp and their combinations). The chemical composition of substrates strongly influences the presence of the immature stages of these biting midges. Higher lignin and insoluble fibre contents seem to favour their presence and could play the role of a physical support for semi-aquatic larvae. In contrast, higher concentrations of magnesium and calcium are negatively correlated with the presence of these two species. These data will help to locate and monitor the breeding sites of these species and could contribute to the control of these insects on farms.

Concepts: Nematocera, Insect, Developmental biology, Larva, Mosquito, Sugar beet, Culicoides, Ceratopogonidae

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A survey to determine current prevalence of Gasterophilus spp. (bot flies) in equids (n=400) at necropsy in slaughtered horses was conducted at the abattoir in Rawicz. The evaluation was performed according to sex, age, larval stages, severity of infestation and localization, respectively. Only Gasterophilus intestinalis and Gasterophilus nasalis were detected. The prevalence determined in the eastern part of Poland was of 47%. The high prevalence of this parasite infection in the Polish horse population confirms that Gasterophilosis spp. has to be taken into serious consideration and prophylactic measures might be indicated.

Concepts: Larva, Horse, Flies, Equus, Equidae, Oestridae, Myiasis, Equine parasites

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Parascaris equorum generally infects horses less than 18 months old and its pathological effects can be severe. Infection occurs when larvated eggs, present in pastures, paddocks, stalls, and on feeding and watering equipment are ingested. The purpose of this study was to examine the effects of windrow composting on the viability of P. equorum eggs at a cooperating central Kentucky horse farm. Three grams of feces containing 2216 P. equorum eggs per gram were sealed in filter bag sentinel chambers. Chambers were exposed to 1 of 3 treatments: constant exposure or intermittent exposure to the interior of the windrow; controls were stored at 4°C. At day 0, all chambers in the experimental treatments were placed in the center of 10 locations of the windrow. On subsequent days when the windrow was turned, chambers in the constant exposure treatment were returned to the interior of the windrow and chambers in the intermittent exposure treatment were alternated between resting on top of, or inside, the windrow. Chambers from each treatment and control chambers were removed at days 2, 4, 6, 8, 10, 12, 14, and 18; and incubated for 21 days at room temperature (24°C). After incubation, eggs were recovered from the chambers using double centrifugation flotation. Eggs were evaluated microscopically, staged according to development and classified as viable or nonviable based on whether embryonation to the larval stage had occurred. Results were reported as the mean percent viable eggs for each treatment and time point. A mixed linear model with repeated measures was used to evaluate the influence of experimental day and treatment on the percent viability of P. equorum eggs. Chambers treated with constant exposure contained 10.73% (SD=0.29) viable eggs on day 2 and declined to an average of 0.00% by day 8. Chambers exposed to the intermittent treatment contained 16.08% (SD=0.26) viable eggs on day 2 and decreased to 0.00% by day 6. Control chambers for days 2, 4, 6, 8, 10, 12, 14, and 18 all had viabilities above 79.00%. A significant fixed effect of experimental day (p<0.0001) and compost treatment (p<0.0001) was observed. There was no significant interaction between experimental day and compost treatment (p>0.7459). The results of this study demonstrate that windrow composting was effective at rendering P. equorum eggs nonviable when it was tested under the conditions at a working horse farm.

Concepts: Larva, Effectiveness, Compost, Composting, British Columbia Interior, Vermicompost, In-vessel composting, Gram

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A genetic analysis of partial sequences of the mitochondrial 16S and 12S rDNA genes of Rhipicephalus sanguineus sensu lato collected in the Southern Cone of South America was carried out. Also, sequences of ticks belonging to this taxon from Europe, Africa and other South American localities were included. TCS networks constructed with 16S rDNA sequences showed two clusters of haplotypes, namely, Southern lineage (ST) and Northern lineage (NT). Haplotypes representing the specimens coming from localities of Argentina, Uruguay and Chile were included in the ST lineage, while haplotypes from Brazil, Paraguay, Colombia, South Africa, Mozambique and from two localities of Northern Argentina were grouped in the NT lineage. The phylogenetic trees obtained with both 16S and 12S sequences showed two distinct clades, one containing R. sanguineus s.l from Argentina, Uruguay, Chile (ST lineage) and Western Europe (Italy and France), and a second clade including R. sanguineus s.l from Argentina, Paraguay, Brazil, Colombia (NT lineage), South Africa and Mozambique. The results herein reported revealed that the taxon R. sanguineus s.l is represented by two lineages in the Southern Cone of South America. According with the genetic comparative analysis, NT lineage and the ticks from Mozambique and South Africa represent a species that is not R. sanguineus s.s, while R. sanguineus s.l ticks from Western Europe and Southern South America (ST lineage) probably represent true R. sanguineus, because the type locality of R. sanguineus s.s is located in France. The taxonomic issue described for R. sanguineus s.l in the South America has epidemiological implications. Difference in the vectorial competence for Ehrlichia canis between the two lineages of R. sanguineus s.l was found in previous works. Further investigations are needed in order to verify a possible different vectorial competence for the other pathogens transmitted by these ticks.

Concepts: Brazil, South America, Americas, Latin America, Chile, Portuguese language, Southern Cone, Operation Condor

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The resistance of gastrointestinal nematodes to anthelmintics has increased the need to evaluate natural products that can replace or assist current strategies to control gastrointestinal nematodes. The objective of this study was to evaluate the effect of decoctions of Lantana camara (DLc), Alpinia zerumbet (DAz), Mentha villosa (DMv) and Tagetes minuta (DTm) on Haemonchus contortus by two in vitro tests. The effects of increasing concentrations of lyophilized decoctions (0.31 to 10mg/ml) were assessed using the egg hatch test (EHT). The decoctions were then tested in the larval artificial exsheathment assay. H. contortus third stage larvae (L3) were exposed to 0.31mg/ml A. zerumbet and M. villosa decoctions and 0.62mg/ml T. minuta and L. camara decoctions for 3h and then exsheathment procedure at 10min intervals. An inhibitor of tannins, polyvinyl polypyrrolidone (PVPP), was used to study if tannins were responsible for the inhibitory effect on hatching and exsheathment of larvae. A. zerumbet, M. villosa and T. minuta showed a dose-dependent effect in the EHT, which did not disappear after the addition of PVPP. No effect was observed for L. camara in the EHT. However, the decoctions inhibited the process of larval exsheathment, which may be related to tannin action because the addition of PVPP reversed the inhibitory effect. A. zerumbet, M. villosa and T. minuta decoctions showed inhibitory activity on H. contortus larvae hatching and exsheathing. The decoctions of these plants could be used to control gastrointestinal nematodes following confirmation of their anthelmintic activity in vivo.

Concepts: Nematode, In vivo, In vitro, Haemonchus contortus, Zingiberaceae, Alpinia, Alpinia zerumbet, Tagetes minuta

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For comparative evaluation, a real time PCR assay was standardized by using TaqMan primer and probe targeting the internal transcribed spacer 1 (ITS-1) region of rRNA for Trypanosoma evansi and sensitivity was evaluated by using DNA, extracted from diethyleamino ethane cellulose purified trypanosomes and trypanosomes infected whole blood of mice. The minimum detection limit for purified trypanosomal DNA was 0.01ng (∼0.33 genomic DNA of T. evansi) whereas for whole blood the minimum detection limit was 0.1ng (∼6.12 genomic DNA). T. evansi infected mice blood samples were collected at different interval post infection and were analysed by conventional parasitological methods (CPT) viz. wet blood smear, thin blood smear, thick blood smear, quantitative buffy coat and real time PCR and found that TaqMan assay was two fold sensitive than CPT in case of in vivo infectivity in mice and gave positive signal at 36h post infection where as QBC and blood smear examination was able to detect at 60h and 72h post infection respectively. A total 109 (80 cattle and 29 buffaloes) blood samples were collected from in and around Ludhiana district and analysed by CPT and real time PCR. The overall prevalence of T. evansi by CPT in cattle and buffaloes was 2.75 per cent. The prevalence rate was 2.5 per cent in cattle and 3.45 per cent in buffaloes. By real time PCR overall prevalence was 12.84 per cent in cattle and buffaloes, with a prevalence rate of 12.50 per cent in cattle and 13.79 per cent in buffaloes.

Concepts: DNA, Time, Polymerase chain reaction, Blood, Trypanosoma, Euglenozoa, Trypanosoma evansi, Buffy coat