Veterinary parasitology最新文献

Ichthyophthirius multifiliis, a pathogenic ciliate, is a crucial pathogen of freshwater fish and can result in severe economic loss in the aquaculture industry worldwide. It is necessary to develop a sensitive and accurate method for detecting I. multifiliis in farming environments and fish skin and gills to protect fishes from infection of the parasite due to a lack of both safe and effective treatment drugs. The present study established a new TaqMan probe-based quantitative PCR (qPCR) detection method targeting the coding region of the cathepsin L cysteine protease (ICP2) gene of I. multifiliis. The sensitivity, specificity, reproducibility and application for detection and diagnosis of the TaqMan probe-based qPCR method were evaluated. In addition, the linear model between the cycle threshold (Ct) and the logarithmic starting quantity (SQ) of the number of theronts per 1 L of sterile water was developed as Ct = -3.312lg(SQ)+ 34.47 with an R² of 0.9636 and a minimum detection limit of 4 theronts per 1 L of water and could be employed to determine the theront number based on Ct value. The results of the detection of trial infection samples with the TaqMan probe-based qPCR method showed that the tissues of fish individuals infected with I. multifiliis and the tank water samples were positive detection signals. In contrast, the tissues and water samples from uninfected fish individuals and tanks containing healthy fish showed no signals. The detection results demonstrated the reliability of this detection method. Overall, the novel TaqMan probe-based qPCR method with high sensitivity and specificity as well as repeatability for detection of I. multifiliis was a valuable tool in detecting the parasite in farming water, pond sediments, and fish tissues and could provide early warning for prevention of the disease caused by I. multifiliis.

Blastocystis is a ubiquitous gastrointestinal protozoan parasite found both in humans and animals. The purpose of this review is to look at the prevalence and genetic diversity of Blastocystis in farm animals, including cattle, sheep, goats, pigs, and poultry, and discuss the potential evidence of transmission between animals and humans, as well as highlight the related risk factors and public health significance. Significant differences have been found in the prevalence of Blastocystis in different hosts worldwide. The global prevalence of Blastocystis infection was 13.6 % in cattle (1219/8961), 15.9 % in sheep (675/4233), 31.7 % in goats (837/2640), 44.57 % in pigs (2589/5808), and 26.29 % in poultry (892/3392). Blastocystis is mainly transmitted through fecal-oral routes. The existence of the same subtypes of the parasite in both animals and humans indicates potential zoonotic transmission. Subtypes ST10 (43.39 %) and ST14 (19.99 %) were most frequently found in cattle, sheep, and goats, while ST5 (62.57 %) was predominantly observed in pigs, and ST6 (16 %) and ST7 (36.6 %) were commonly recorded in poultry. Analysis of risk factors suggests that age, sex, close contact with animals, geographical location, farm management system, and season were the significant risk factors reported in many studies. Although epidemiology and subtype distribution of Blastocystis in different hosts have been described in several studies, understanding the possible transmission pathway from farm animals to humans and the public health impacts of Blastocystis requires more extensive studies.

Trichinella spiralis infection is a serious parasitic zoonosis in which a collagenous capsule surrounding the larva is developed in the striated muscle cells. However, the mechanism of T. spiralis encapsulation is currently poorly understood. It has been reported that T. spiralis infection can induce the production of IL-13 via the NLRP3 inflammasome, and it has also been suggested IL-13 thus produced may be involved in T. spiralis encapsulation. This research aimed to clarify the involvement of NLRP3 and IL-13 in the T. spiralis capsule formation process. IL-13 and NLRP3 inhibitors were used in a T. spiralis infected mouse model and in C₂C₁₂ cells to analyze the role of IL-13 and NLRP3 in encapsulation. The results showed that T. spiralis infection significantly increased the expression levels of IL-13 and collagen IV and VI. The production of collagen around the T. spiralis encapsulation zone was significantly inhibited when an IL-13 inhibitor was applied. Moreover, the expression levels of IL-13 and collagen IV and VI were significantly decreased by the NLRP3 inhibitor in vitro and in vivo. The above results indicated that NLRP3 can participate in the development of T. spiralis encapsulation by regulating IL-13 expression and stimulating collagen IV and VI synthesis during T. spiralis infection.

Canine monocytic ehrlichiosis (CME), induced by Ehrlichia canis, is an important infectious disease in dogs, characterized by various clinical signs and consequent immune dysfunction. This study aimed to characterize nuclear morphology, chromatin compaction, histone H3 acetylation, and DNA methylation in lymphocytes from dogs naturally infected with E. canis, compared with healthy controls. A total of 30 dogs were included in this study, comprising 15 healthy dogs and 15 dogs with confirmed E. canis infection, verified through polymerase chain reaction. Blood samples were collected from these dogs to isolate peripheral blood mononuclear cells. The isolated cells were prepared into smears and stained using the Feulgen reaction for subsequent analysis. These stained smears underwent video imaging analysis to assess nuclear morphology and chromatin parameters. Additionally, lymphocytes isolated from the PBMCs were analyzed to quantify global levels of histone H3 acetylation and DNA methylation. The results indicated significant increases in nuclear size and alterations in chromatin architecture in the lymphocytes of dogs with E. canis infection. A significant reduction in histone H3 acetylation was observed in this group, suggesting a potential mechanism of transcriptional repression. In contrast, no significant differences in DNA methylation were detected between the infected dogs and the healthy controls. In conclusion, our findings reveal distinct morphological and epigenetic alterations in lymphocytes associated with E. canis infection, thereby enhancing the understanding of the immune dysfunction observed in dogs with CME.

Currently, the 'gold standard' for diagnosis of Psoroptes ovis infections is detecting Psoroptes mites or eggs in skin scrapings under microscopy, but it is prone to be mis-diagnosed for detecting early infection of P. ovis. Hence, seeking a reliable diagnostic technique for detecting early-stage mite infections is extremely desirable. Enzyme linked immunosorbent assay (ELISA) has proven to be useful for the diagnosis of early-stage P. ovis infection. Thus, the purpose of this study was to screen serodiagnostic candidate antigens that can detect early P. ovis infection. Psoroptes ovis var. cuniculi wash proteins (PsoWA), which contained an enriched source of secretory and excretory antigens, were separated by two-dimensional gel electrophoresis (2-DE) and screened by immunoblot using sera from rabbits with early-stage Psoroptes infection (1 week and 3 weeks). Immunogenic proteins were submitted for sequencing by liquid chromatography tandem-mass spectrometry (LC-MS/MS) analyses. Three potential diagnostic antigens were identified (PsoSP3, Pso14-3-3(1) and Pso14-3-3(2)) in this study. These were further expressed in E. coli expression system to evaluate the serodiagnostic potential of these recombinant proteins for detecting early-stage P. ovis infection using an indirect ELISA (iELISA). Western blotting showed that 34 protein spots were recognized by rabbit sera of 1 week post-infection (wpi) and 3 wpi. The 2-DE results showed that a total of 199 proteins were detected with molecular weights varying from 20 to 100 kDa and isoelectric point (pI) from 4.1 to 9.3. Among these, 90 proteins were detected both at 1 wpi sera and 3 wpi sera, and the numbers of the specific identified proteins were 27 for 1 wpi sera and 82 for 3wpi sera. Moreover, rPsoSP3 showed better diagnostic efficacy than rPso14-3-3(1) and rPso14-3-3(2) in detecting early-stage P. ovis infection for its higher values of sensitivity, specificity and area under the receiver operating characteristic curve. Our study describes the first immunoproteomic analysis to identify early diagnostic candidate antigens of P. ovis, and the identified antigens of Psoroptes in our study have significant implications for the development of early-stage diagnostic tests. PsoSP3 is a promising early diagnostic antigen for detecting P. ovis var. cuniculi infection.

The aim of this work is to present a case study where the failure of IVM 3.15 % and DRM 1 % to prevent natural infestations of C. hominivorax larvae in Argentina is investigated based on field efficacy tests and a pharmacokinetic and pharmacodynamic analysis. Thirty male crossbred Braford calves were randomly assigned to three experimental groups (n = 10), the IVM 3.15 % group (subcutaneously at 630 µg/kg), the DRM 1 % group (subcutaneously at 200 µg/kg) and the control group (saline solution subcutaneously). All treatments were performed at the time of castration surgery through a scrotal incision, and the wounds were exposed to natural infestations of C. hominivorax. Wound inspections were carried out on days 3, 6, and 13 post-treatments. Jugular blood samples were taken from experimental animals at 3- and 6-days post-treatment. In presence of C. hominivorax larvae, samples of both the larvae and wound secretions were collected in plastic vials on days 3 and 6 to measure concentrations of both drugs by high-performance liquid chromatography. On day 3 post-treatment, active myiasis was observed in 9 animals from the control group, 5 from the IVM 3.15 % group, and 6 from the DRM 1 % group. On day 6 post-treatment, 5 and 3 new myiasis were detected in the IVM 3.15 % and DRM 1 % group, respectively. No larvae were observed in the wounds on day 13 post-treatment. Interestingly, DRM concentrations tended to be higher in larvae compared to IVM on day 3 post-treatment (p = 0.051), and IVM plasma concentrations tended to be higher than those measured for DRM on day 6 (p = 0.087). There was a very strong correlation between DRM and IVM concentrations in plasma and wound secretions and larvae. The uptake of DRM from wound secretions to larvae was 83 % greater than that of IVM (p = 0.03). The results of this trial suggest the presence of C. hominivorax resistance to DRM and highlight concern about the lack of effectiveness of IVM 3.15 % in preventing C. hominivorax infestations.

Equine piroplasmosis (EP) is a tick-borne disease of equids caused by Theileria equi, Theileria haneyi, and Babesia caballi. EP is endemic in most tropical and subtropical regions worldwide, and there is a likelihood that it is also endemic in Portugal. This retrospective study aimed to determine the seroprevalence, prevalence, and potential risk factors of EP in our country over the past five years. A total of 3063 diagnostic test records were analysed. Results from the competitive enzyme-linked immunosorbent assay (cELISA) revealed a seroprevalence of 32.7 % and 15.7 % for T. equi and B. caballi, respectively, with a coinfection rate of 7.4 %. For the indirect fluorescent antibody test (IFAT), 38.8 % of the samples were positive for T. equi, 45.7 % for B. caballi, and 23.1 % for both parasites. Prevalence determined using quantitative polymerase chain reaction (qPCR) showed 40.5 % T. equi-positive cases, 8.3 % B. caballi-positive cases, and 3.2 % mixed infections in the studied population. Considering risk factors, age and season appear to be associated with higher seropositivity, and location was also found to play a significant role. This study represents the first retrospective analysis carried out in Portugal, confirming the endemicity of EP in the country. Further studies are needed to corroborate our findings, to determine actual prevalence and seroprevalence in the Portuguese general equine population, and to identify risk factors better, helping breeders and owners to minimise the health and economic impact of EP.

Coccidiosis, infection with protozoan parasites of genus Eimeria, is a major problem in poultry husbandry world-wide. The disease is currently managed by coccidiostats and live vaccines, but these approaches are not sustainable. Hence, it is important to identify new means to control the infection and/or ameliorate its detrimental effects on gut health. Laminarin, a β-glucan found in marine brown algae, has prebiotic and bioactive properties that could be beneficial in coccidiosis control. The present study aimed to examine the potential of laminarin as an immunostimulatory and microbiota-regulatory compound in broiler chickens infected with E. tenella. Chickens were continuously fed a diet supplemented with a laminarin-rich algal extract (AE) from first feed and subsequently infected with E. tenella at 19 days old. The outcome of infection including caecal microbiota and some immune parameters were monitored during the experiment. Results showed that AE supplementation affected some lymphocyte subpopulations, with increased numbers of TCRγ/δ+CD8-, B-cells and CD4-CD8αβ+ cells and lower numbers of CD4+CD8αα+ cells in blood and increased proportions of CD4-CD8αβ+ spleen cells compared to those in control chickens. The AE diet did not affect parasite excretion, lesion scores or E. tenella specific T-cell responses. However, reductions of E. tenella induced contraction of Bifidobacteriaceae and expansion of Clostridiaceae in caecal microbiota were observed for AE fed chickens compared to chickens fed the control diet. Thus, AE feed supplementation induced some immunostimulatory activity in chickens and affected some of the alterations in caecal microbiota evoked by E. tenella infection.

The equine bloodworm, Strongylus vulgaris, is a common and highly pathogenic parasite in horses due to its migratory life cycle involving the intestinal arteries. Current diagnostic techniques cannot detect the prepatent migrating stages of S. vulgaris, highlighting the need for new biomarkers. Parasites release microRNAs (miRNAs) into their environment, which could potentially be detectable in host blood samples. Additionally, host miRNA expression patterns may change in response to infection. This study aimed to identify miRNAs associated with S. vulgaris infection by profiling the horse's miRNA response in the larval predilection site, the Cranial Mesenteric Artery (CMA) and examining the circulating parasite and horse-derived miRNAs in plasma of S. vulgaris-infected horses. Plasma samples were collected from 27 horses naturally infected with S. vulgaris and 28 uninfected horses. Arterial tissue samples from the CMA and Aorta were collected from a subset (n = 12) of the infected horses. Small RNA sequencing (small RNAseq) of a subset of the plasma samples (n = 12) identified miRNAs of interest, followed by quantitative real-time PCR (qPCR) evaluation of selected miRNAs in plasma from a larger cohort of horses. Small RNAseq detected 138 parasite-derived and 533 horse-derived miRNAs in the plasma samples. No difference in parasite-derived miRNA abundance was found between the infected and uninfected horses, but 140 horse-derived miRNAs were significantly differentially abundant between the two groups. When evaluated by qPCR, none of the selected parasite-derived miRNAs were detectable in plasma, but seven horse-derived miRNAs were confirmed differentially abundant in plasma between the two groups. Seven horse-derived miRNAs were differentially expressed in CMA tissue affected by migrating S. vulgaris compared with unaffected aortic tissue, with Eca-Mir-223-3p (Log2FC: 4.74) and Eca-Mir-140-3p (Log2FC: -3.64) being most differentially expressed. A receiver operating characteristic curve analysis suggested that Eca-Mir-486-5p and Eca-Mir-140-3p had the best diagnostic performance for distinguishing between infected and uninfected horses, with areas under the curve (AUC) of 0.78 and 0.77, respectively. Notably, Eca-Mir-140-3p was associated with age, and correcting for interaction with age increased the AUC to 0.96. In conclusion, several horse-derived miRNAs were associated with S. vulgaris infection and could differentiate between infected and uninfected horses based on their plasma abundance. However, the levels of these miRNAs were influenced by other factors (i.e age, breed), complicating their use as biomarkers. Parasite-derived miRNA abundance did not differ between S. vulgaris infected horses and those infected with other parasites using small RNAseq and were below detection limits of qPCR.