Veterinary parasitology最新文献

The acaricidal potential of various essential oils (EOs) has been evaluated based on their benefits in tick control. This study aimed to investigate the tick-killing activity of Pogostemon cablin “patchouli,” Cymbopogon martinii “palmarosa,” and Cymbopogon flexuosus “lemongrass” EOs on Rhipicephalus linnaei. Engorged females were collected from domiciled and non-domiciled dogs from Jataí city, Goiás state, to obtain larvae and nymphs in a controlled environment. Two commercial EOs brands were used in this study in different EOs concentrations (2.5, 5, 10, and 20 mg/mL), and was tested by immersion of larvae and nymphs. In the in vitro evaluation of EOs toxicity against R. linnaei larvae, 100 % mortality was achieved with 10 mg/mL of P. cablin oil, whereas mortality rates greater than 98 % were observed with 20 mg/mL of C. martinii and C. flexuosus. In nymphs, high sensitivity was observed, with 100 % mortality achieved using 5 mg/mL of P. cablin and 20 mg/mL of C. martinii and C. flexuosus. The EO of P. cablin “patchouli” demonstrated in vitro toxicity at a lower concentration than the other oils in the two development stages of R. linnaei, and was considered the most efficient and with verified acaricidal activity. Oils of C. martinii “palmarosa” and C. flexuosus “lemongrass” achieved mortality greater than 95 % in larvae and nymphs only at the highest concentration. Therefore, the acaricidal effects of the tested EOs are promising, especially of patchouli oil, which promoted high mortality at a low concentration (LC₉₀ of 2.21 mg/mL).

Coccidiosis poses a significant challenge to the poultry industry. However, the excessive and improper use of anticoccidial drugs and vaccines has led to resistance and food safety concerns. Consequently, traditional Chinese herbs have garnered attention as a potentially safer and more effective alternative. ChangQing compound derived from various Chinese herbal medicines is a promising anticoccidiosis agent, but its therapeutic effects have not been comprehensively evaluated. This study aimed to assess the therapeutic efficacy of ChangQing Compound against Eimeria tenella-induced coccidiosis in chickens on the basis of physiological indicators, cecum lesions, and changes in microbial diversity. The comparison with the positive control group revealed the average weight gain (AWG) and anticoccidial index (ACI) of the chicks were significantly higher, in contrast, the feed conversion ratio (FCR), cecal lesion score (CLS), and oocyst count per gram of cecal content (OPG) were significantly lower (P<0.05). Notably, AWG (138.87 g), OPG (0.57 × 10⁶), ACI (177.92), and FCR (2.51) reflected the significant therapeutic effect of the 2.5 g/L ChangQing compound treatment (CQM). Histological sections showed that the cecal villus damage and intestinal wall swelling were minimal in the CQM, consistent with the CLS (0.73). Additionally, the 2.5 g/L ChangQing compound treatment effectively prevented the decrease of red blood cells, platelets, and hemoglobin, while promoting the release of anti-inflammatory factors interleukin-10 and interleukin-4, and inhibiting the pro-inflammatory factors interferon-γ and interleukin-17. The microbial community structure in the CQM was most similar to that of the negative control group. In summary, ChangQing compound had multiple positive effects (e.g., promoting weight gain, alleviating anemia, suppressing coccidial proliferation, reducing intestinal damage, modulating immunity, and maintaining intestinal microbiota homeostasis). The study results may be relevant to developing a novel strategy for the clinical management of coccidiosis.

The present study aimed to evaluate under dairy farm conditions the predisposing factors, impact on milk production and productivity, and the role of Rhipicephalus microplus in the epidemiology of tick fever agents in Holstein calves grazing in a tropical region. A total of 4292 pure female Holsteins were evaluated at a commercial farm. Until April 2020, calves had contact with R. microplus for between 3 and 24 months, while after April 2020, no animal had further contact with ticks. Three times a week the rectal temperature (RT) of all animals was determined, and blood samples were collected for evaluation of tick fever (TF) agents from those that showed RT >39.3 °C. Specific treatment was performed against Anaplasma marginale, Babesia bigemina and Babesia bovis when these TF agents were diagnosed in the blood smears. The number of relapses and treatments for TF agents were sub-classified into scales (1, 2, 3, 4, 5, 6 or 7–10 treatments or relapses, and animals that received blood transfusions). Within each sub-class, the health data of calves during lactation along with productivity data were analyzed. Based in the results, whether an animal received colostrum enriched with powdered colostrum substitute, whether the animal was an embryo transfer calf, and the weight at which each calf was weaned were ascertained as factors leading to more recurrences or treatments against TF agents in post-weaned calves. On average, each recurrence of TF agents that a heifer presented between three and seven months decreased milk production by 213.5 liters in the first lactation. Calves that received a blood transfusion had lower milk production at first lactation; lower weight at first fixed-time artificial insemination (FTAI); older age at first FTAI; older age at first, second, and third calving; and delayed age at third calving by 140 days compared to the farm average. R. microplus was the main agent causing clinical cases of TF on the farm, and 10,770 treatments against TF agents were carried out when calves aged between three and seven months had contact with this tick species (2018 and 2019). When the animals no longer had contact with ticks (2022 and 2023), there were no recurrences or treatments against TF agents despite the presence on the farm of S. calcitrans, which can maintain the transmission of A. marginale to the herd.

Parasitic infections with gastrointestinal nematodes are a serious problem for the health and welfare of domestic animals and negatively affect the economics of animal production. Haemonchus contortus is a haematophagous nematode of small ruminants responsible for significant mortality and morbidity. In addition, the widespread resistance to synthetic anthelmintic drugs emphasizes the urgent need of alternative treatment options against haemonchosis. This work aims to investigate the anthelmintic activity of an hydroethanolic Combretum mucronatum leaf extract (CMLE) against Haemonchus contortus in goats. Goats were artificially infected with 3500 third-stage larvae of H. contortus, and 21 days later, treated with CMLE (1000, 500, 250 mg/kg) for 4 consecutive days. Different parameters such as faecal egg count reduction, weight and haematocrit were monitored during the experimental period. The number of eggs per gram of faeces (EPG) was concentration-depended lower and significantly reduced compared to the untreated control (p < 0.0001). The effect of the highest CMLE dose (4 ×1000 mg/kg body weight) was similar to the effect of albendazole (1 ×5 mg/kg of body weight). The ED₅₀ and ED₉₀ values calculated were 189.17 and 392.33 mg/kg body weight respectively. ED₅₀ and ED₉₀ values were time-dependent. Moreover, CMLE improved haematocrit and weight of goats in dose-dependent and time-dependent manner. These results showed that CMLE could be used for haemonchosis treatment in small ruminants.

The objective was to determine host animal protein/amino acid redistribution and use among the abomasum, duodenum and muscle of sheep infected with Haemonchus contortus. Sixteen male Ujumqin sheep (32.4 ± 3.9 kg) were dewormed and randomly assigned to two groups, infected or not infected with H. contortus (GIN and CON). The GIN group had lower (P < 0.05) dry matter intake, average daily gain, and live body weight than CON, with extensive focal infiltration of lymphocytes in the lamina propria and bottom of the abomasal epithelium. In the abomasum and duodenum, there were 100 and 220 genes, respectively, that were up-regulated, whereas 56 and 149 were down-regulated. In the abomasum, the most enriched KEGG pathways were related to immunity and inflammation reaction, including: viral protein interaction with cytokine and cytokine receptor (P = 0.017), influenza A (P = 0.030), IL-17 signaling pathway (P = 0.030). In the duodenum, KEGG pathways were more enriched in nutrient metabolism, including pancreatic secretion (P < 0.001), protein digestion and absorption (P < 0.001), graft-versus-host disease (P = 0.004). Furthermore, most genes related with the above KEGG pathways were increased in the abomasum but decreased in the duodenum. Amino acid profiles in abomasum and duodenum of CON and GIN groups were clustered in a partial least-squares discriminant analysis model, with significant changes in 36 and 19 metabolites in abomasal and duodenal chyme, respectively. Further confirmed by transcriptome-targeted metabolome association analysis, GIN mainly enhanced metabolism of arginine and sulphur amino acids in abomasum and those metabolic pathways were associated. Meanwhile, GIN mainly decreased pyruvate related amino acid metabolism in duodenum. Moreover, concentrations of Arg (P = 0.036), His (P = 0.027), and Cys (P = 0.046) in longissimus thoracis et lumborum were decreased in GIN, whereas concentrations of Gly (P = 0.012) and Ala (P = 0.046) were increased. In conclusion, H. contortus enhanced metabolism of arginine and sulphur amino acids in the abomasum; decreased pyruvate metabolism in the duodenum; and drove more protein/amino acids for abomasal tissues to resist physical and immune damage, reducing protein and amino acids in duodenum and muscle for support host growth. Specific nutrients (such like arginine, histidine, and cysteine) may play important role in control gastrointestinal nematode infection for ruminant.

Coccidiosis is a highly significant disease in domestic animals due to its global distribution and economic impact. The occurrence of oxidative stress (OS) and the acute phase response (APR) play crucial roles in the development of coccidiosis, thereby contributing to the pathogenicity of coccidia. A range of triggers including parasitic infection, can induce the APR. This response encompasses a set of hormonal and metabolic changes to restore body stability and improve the body's healing capabilities. Ovine coccidiosis has the potential to cause OS, which can be prevented and treated through the use of dietary additives. By including Curcuma longa in the diets of infected sheep, it is possible to reduce lipid peroxidation (LPO) and nitric oxide (NO) production, while simultaneously improving serum antioxidant capacity and interleukin-10 (IL-10) levels. Caprine coccidiosis can activate the APR. Research indicated that goats suffering from coccidiosis exhibited elevated concentrations of malondialdehyde (MDA) and total homocysteine, along with reduced levels of some enzymes such as superoxide dismutase (SOD) and glutathione reductase (GR), as well as decreased levels of zinc (Zn), manganese (Mn), selenium (Se), vitamin C, and total antioxidant capacity (TAC). Bovine coccidiosis is linked to elevated MDA concentrations and reduced serum glutathione (GSH) and TAC levels. Eimeria can induce OS and inflammatory damage in infected birds by releasing pro-inflammatory mediators from cells, resulting in a significant increase in CAT and SOD activity, lipid peroxidation and damage to the intestinal epithelium. To promote the antioxidant system of infected birds, some herbal food additives such as grape seed proanthocyanidine extract, Curcuma longa and Rumex nervosus leaf extract, can be used. Research on the APR in birds is not as extensive as in ruminants. Currently, there is a lack of studies on the occurrence of OS and APR in camels, horses, dogs, and cats with coccidiosis.

The aim of this study was to evaluate embryo transfer in cattle as a pathway of transmitting neosporosis and to quantitatively and qualitatively compare the embryo production from seropositive and seronegative donors. Superovulatory treatments were performed on eight Girolando donors (four seropositive and four seronegative for N. caninum), resulting in the recovery of ninety-one structures (embryos and non-fertilized structures). Embryos collected and classified as viable were transferred to seronegative recipients and analyzed by PCR to identify N. caninum. No difference was observed in the number of structures collected from seropositive and seronegative donors (40 and 51; P = 0.64). There was a significant difference in the percentages of freezable (25 % and 74 %, P = 0.04) and transferable (27.5 % and 78.4 %, P = 0.003) embryos. The recipients had similar pregnancy rates (60 % and 57.1 %, P = 0.97) and pregnancy loss (50 % and 43.8 %, P = 0.58). There was no change in the serological status of the recipients, and no protozoan DNA was identified in none of the samples. It was concluded that the embryo transfer technique is safe regarding the transmission of neosporosis; however, the quality of embryo production was compromised from donors seropositive for N. caninum.

Economic importance of ticks for both humans and animals is significant primarily because of their involvement in disease transmission. The continuous use of synthetic chemical acaricides on animals and/or in the environment has resulted in the emergence of resistant tick populations. Consequently, there is a compelling need to explore newer natural alternatives that can address their adverse effects effectively. Since, there are no earlier reported studies on the acaricidal activity of eugenol and benzaldehyde against Rhipicephalus annulatus, the present study compared the in vitro adulticidal and larvicidal activities of these phytochemicals against R. annulatus. Concentration-dependent mortality and inhibition of fecundity were observed in the adult female ticks treated with both eugenol and benzaldehyde. The LC₅₀ and LC₉₀ values of eugenol against R. annulatus were 162.33 and 467.74 mg/mL for adult female, while it was 1.26 and 1.73 mg/mL for larvae respectively. The LC₅₀ and LC₉₀ values of benzaldehyde against R. annulatus were 178 and 395 mg/mL for adult female and 0.69 and 4.32 mg/mL for larvae respectively.

Neospora caninum (N. caninum) is an obligate intracellular Apicomplexa parasite that causes abortions in dairy cows and incurs substantial to significant economic losses in the global dairy farming industry. Cordycepin, a nucleoside antibiotic derived from Chinese medicine Cordyceps militaries, exhibits diverse biological activities. However, it remains unclear whether cordycepin possesses inhibitory effects against N. caninum infection. Therefore, this study aimed to establish both in vivo and in vitro models of N. caninum to investigate the potential impact of cordycepin against N. caninum infection. We successfully established an in vitro model of N. caninum infection in RAW264.7 cells, followed by qRT- PCR analysis to detect the content of N. caninum DNA within the cells. The effects of cordycepin on N. caninum was observed using the Giemsa method on RAW264.7, and the rate of cell infection was calculated. Cordycepin exhibited inhibitory effects on N. caninum tachyzoites in vitro, preserving cellular integrity and reducing the rate of cell infection. In mice, we established an in vivo model of N. caninum infection and detected N. caninum presence in tissues using. Real-time fluorescence quantitative PCR. Histopathological changes were observed through Hematoxylin-eosin staining. Liver function was assessed by using glutamic acid aminotransferase (ALT) and aspartic acid aminotransferase (AST) kits. Oxidative stress status was measured using catalase (CAT), malondialdehyde (MDA), and glutathione (GSH) kits. Compared with the model group, mice treated with cordycepin showed reduced clinical symptoms, increased food intake, and their body weight (P=0.0143, P=0.0068) was significantly higher than those in the model group. Furthermore, cordycepin treatment significantly alleviated hepatic cord disorders, hepatocellular swelling, detachment, and vacuolization; duodenal epithelial detachment and shortening of villi caused by N. caninum infection. Cordycepin administration reduced the increase in ALT (P=0.01, P=0.008) and AST (P<0.001) levels caused by N. caninum infection, while ameliorating hepatocyte swelling, necrosis, and detachment as well as inflammatory cell infiltration within mice liver; it also led to shortened or even disappeared duodenal villi along with and oedema of the submucosa. Analysis of oxidative stress showed that cordycepin ameliorated the damage caused by N. caninum by reducing MDA (P=0.03, P=0.02, P=0.005) and increasing CAT (P=0.004, P<0.001) and GSH (P=0.004, P<0.001) levels. In conclusion, this study reports for the first time on cordycepin’s efficacy against N. caninum infection providing a potential candidate drug for neosporosis treatment.

The aim of this study was to identify factors that play a key role in the epidemiology of bovine anaplasmosis by adapting a model primarily developed for cattle babesiosis. A cross-sectional observational study was conducted to study the proportion of calf herds in endemic stability/instability for A. marginale in a semi-arid area of Argentina. The A. marginale inoculation rate (h) was calculated from age-specific seroprevalence using double-antigen sandwich ELISA in 58 herds of 4.5–8.5-month–old calves. Herds were considered to be in endemic instability (EI) at h < 0.005 and, therefore, at risk of anaplasmosis outbreaks. A generalized linear model was performed to explore husbandry practices associated with differences in A. marginale transmission. Additionally, spatial clustering of herds with the same immunological status was analyzed using spatial scan statistics (SatScan, Bernoulli model). Spearman's correlation was used to explore a possible association between A. marginale h and Babesia bovis and B. bigemina h (data obtained in previous works). Almost half (43 %) of the herds were in the EI zone for A. marginale. Calves raised under forage combinations had a greater risk of being in EI (OR = 5.41, CI95 %OR = 1.43–20.41) than those reared exclusively on permanent pastures, where cattle density is higher (P = 0.01). Moreover, calves from herds treated only with pyrethroids to control ticks had more chances of being in EI (OR = 4.16, CI95 %OR = 1.12–15.38) than calves from herds receiving different acaricide combinations (P = 0.03). Calves from herds subjected to more than two treatments against Haematobia irritans had higher odds for EI (OR = 5.69, CI95 %OR = 1.24–26.11) than those from herds using fewer than two treatments (P = 0.02). The spatial analysis revealed no spatial clustering of the immune status of the herds (P = 0.67 and P = 0.74 for low and high incidence rates, respectively). A significant variation between farms was observed in A. marginale h (CV = 90.38 %). The correlation analysis revealed a strong epidemiological link of A. marginale h with B. bovis h (Rho=0.794, P<0.001) and B. bigemina h (Rho=0.839, P<0.001). Given that R. microplus is the only vector of B. bovis and B. bigemina in the region, the results of this work strongly suggest an active and significant role of R. microplus in the transmission of A. marginale.