首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
More effective vaccines against Toxoplasma gondii may contribute to the control of this pathogen that has major veterinary and public health significance. In this study, two recombinant plasmids pcDNA/TgSAG1 and pVAX/mIL-18 containing T. gondii SAG1 (TgSAG1) and murine cytokine interleukin-18 (IL-18) were evaluated for their ability to protect mice against T. gondii challenge. Mice were given two intramuscular immunizations 3 weeks apart, and challenged with T. gondii 3 weeks later. All animals vaccinated with pcDNA/TgSAG1 alone or with pVAX/mIL-18 developed specific anti-TLA (T. gondii lysate antigen) antibodies and specific lymphocyte proliferative responses. Co-injection of pVAX/mIL-18 significantly increased the production of IFN-γ and IL-2. Further, challenge experiments showed that co-immunization with pVAX/mIL-18 significantly (P < 0.05) increased the survival rate (60%), compared with pcDNA/TgSAG1 alone (40%). Therefore, codelivery of the IL-18-secreting plasmid potentiates the induction and maintenance of the type 1 helper T-cell immune response and may be a potent strategy for enhancing the protective efficacy of vaccines against T. gondii.  相似文献   

2.
The prevalence of antibodies to the protozoan parasites Toxoplasma gondii and Neospora caninum were investigated by the direct agglutination test (DAT) and cELISA, respectively, in 160 roe deer (Capreolus capreolus), 177 sheep and 178 cattle sharing pastures in Galicia (Northwest Spain). The seroprevalence for T. gondii was 13.7% in roe deer, 57% in sheep and 7.3% in cattle. The seroprevalence for N. canimum was 6.8%, 10.1% and 24.1% in roe deer, sheep and cattle, respectively. Statistically significant differences were observed between sheep and the other species for T. gondii and between cattle and the other ruminants for N. caninum. Only 19/515 animals were positive for both, T. gondii and N. caninum. Statistically significant differences were observed among different geographical areas for T. gondii but not for Neospora, seroprevalence being higher in the coastal area lower than in other areas. This study reveals a widespread exposure to T. gondii in Galician ruminants, and therefore, those species, particularly sheep, should be regarded as a potential source of infection for humans.  相似文献   

3.
Seroprevalence and associated risk factors for Toxoplasma gondii infection in pigs were analyzed in 1202 sera samples, including sows and pigs of three, seven, 11, 15 and 20 weeks of age, from 23 farms in Catalonia, north-eastern Spain. Antibodies were tested by the modified agglutination test (MAT) at titers ?1:25. Antibodies to T. gondii were found in 228 samples (19.0%; 95% CI: 16.8-21.2). The individual prevalence in animals higher than 7 weeks of age was 22.8% (174/762; 95% CI: 16.6-29.0) and the within-farm prevalence ranged from 7.1% to 36.4%. Statistically significant differences were found among age classes. The risk factors significantly associated with T. gondii seroprevalence were the presence of cats, percentage of mortality at weaning and the presence of outdoor facilities in the farms. The seroprevalence observed in the present study indicates widespread exposure to T. gondii among domestic pigs in Catalonia, which may have important implications for public health.  相似文献   

4.
The aim of this study was to assess the effects of a synbiotic composed of Bifidobacterium animalis and fructooligosaccharides on female rats infected with Toxoplasma gondii. Female Wistar rats, treated or not with dexamethasone, were daily supplemented with synbiotics for 21 days. After 15 days of supplementation, the rats were orally infected with 104T. gondii bradyzoites. Blood samples were collected to measure the levels of IFN-γ, IL-10 and T. gondii antibodies. All synbiotic-supplemented rats survived until the end of the experiment; however, non-supplemented dexamethasone-treated rats died between the fifth and the eighth days after T. gondii infection. Dexamethasone-treated rats supplemented with synbiotics (P < 0.05) were capable of synthesizing IFN-γ, and this immunological response was essential to ensure their survival. In addition, brain cysts were found in one rat not supplemented with synbiotics. Results suggest that the synbiotic composed of B. animalis and fructooligosaccharides may be beneficial to toxoplasmosis control.  相似文献   

5.
Wild felids are considered important in maintaining the sylvatic cycle of Toxoplasma gondii. Although, T. gondii antibodies have been reported in several species of wild felids, little is known of the epidemiology and risk factors associated with T. gondii infection in wild cats. The Iberian lynx (Lynx pardinus) is the most endangered felid species in the world. In the present study, seroprevalence and associated risk factors for T. gondii infection in a large population of Iberian lynx in Spain were determined. Serum samples from 129 Iberian lynx collected from 2005 to 2009 and 85 wild rabbits (Oryctolagus cuniculus), sharing the habitat with the Iberian lynx, were tested for antibodies to T. gondii by the modified agglutination test (MAT) using a cut-off value of 1:25. Antibodies to T. gondii were found in 81 of 129 (62.8%) Iberian lynx. Seroprevalence to T. gondii in Iberian lynx significantly increased with age (P < 0.001). T. gondii seroprevalences were similar in free-ranging (66.7% of 93) and wild-caught captive lynx (69% of 84) but significantly lower in captive-born lynx (22.5% of 40). Seroprevalence was higher in lynx with concurrent Cytauxzoonfelis (88% of 25) but not with concurrent Feline Leukemia Virus (FeLV) infection (53.8% of 13). There were no significant differences in seroprevalence between sexes, geographic region and year of sample collection (2005–2009). Oocysts of T. gondii were not detected microscopically in fecal samples from 58 lynx. Wild rabbits are considered the most important food for the lynx. Antibodies to T. gondii were found in 14 (11.9%) of 85 rabbits tested. The present results indicate that T. gondii infection is widespread in the two areas where Iberian lynx survive in Spain. The fact that four captive-born lynx seroconverted was indication of contact with T. gondii also in the Captive Breeding Centers, hence, control measures to prevent T. gondii infection would be necessary in these centers.  相似文献   

6.
  相似文献   

7.

Background

Toxoplasma gondii is a major problem for the sheep industry as it may cause reproduction problems. The importance of T. gondii in Norwegian goat herds is uncertain, but outbreaks of toxoplasmosis in dairy goat farms have been recorded. The aim of this study was to describe the prevalence of T. gondii infection in Norwegian dairy goats by using serology.

Findings

Goat serum originally collected as part of two nationwide surveillance and control programmes between 2002 and 2008 were examined for T. gondii antibodies by using direct agglutination test. In total, 55 of 73 herds (75%) had one or more serologically positive animals, while 377 of 2188 (17%) of the individual samples tested positive for T. gondii antibodies.

Conclusions

This is the first prevalence study of T. gondii infection in Norwegian goats. The results show that Norwegian goat herds are commonly exposed to T. gondii. Nevertheless, the majority of goat herds have a low prevalence of antibody positive animals, which make them vulnerable to infections with T. gondii during the gestation period.  相似文献   

8.
The aim of this study was to describe the occurrence of antibodies to Toxoplasma gondii and Neospora caninum in dairy sheep from the Humid Pampa region, Argentina. Blood samples from 704 dairy sheep belonging to six flocks were collected. Using a cut off titer of 1:50, an indirect fluorescence antibody test was used. Antibodies to T. gondii or N. caninum were detected in 17.3 % (n?=?122) and 3 % (n?=?21), respectively. All the flocks had at least one seropositive animal to T. gondii but two of them had no seropositive sheep to N. caninum. Fifty-two of 122 (42.6 %) positive samples to T. gondii had antibody titers higher than 1:400. There was a significantly higher proportion of T. gondii seropositive animals in females and older sheep (p?<?0.05). Ten of 21 (52.3 %) positive samples to N. caninum had antibody titers higher than 1:400. This is the first report of seroprevalence of T. gondii and N. caninum in dairy sheep from Humid Pampa, Argentina. Further research is required for a better understanding of the role of toxoplasmosis and neosporosis in dairy sheep in Argentina.  相似文献   

9.
Johne's disease is chronic granulomatous infectious enteritis of animals caused by Mycobacterium avium subspecies paratuberculosis. A total of 153 animals from 19 dairy farms, 2 gaushalas (unproductive-animal rehabilitation centers), 2 goat and 2 sheep farms from different districts of the Punjab region were selected on the basis of clinical signs of disease. All samples from cattle (n = 86), buffalo (n = 34), goat (n = 25) and sheep (n = 26) were subjected to Ziehl-Neelsen staining and DNA extraction by a freeze and thaw method. Ziehl-Neelsen staining detected 71% samples positive for acid-fast bacilli whereas IS900 PCR detected 55% positive for Map DNA. IS1311 PCR-REA analysis of IS900 positive samples revealed ‘Bison’ type as the most prevalent (82%) genotype of Map, infecting all domestic ruminants. ‘Cattle’ type was present in a minority of cases (15%) from cattle, buffaloes and goats. This is the first report of ‘Cattle’ type Map from buffalo and goat species in India.  相似文献   

10.
Intramammary infections are a serious problem for dairy sheep farms, and Staphylococcus epidermidis is one of the main etiological agents of ovine mastitis. In this work, 131 S. epidermidis isolates, collected from 2201 dairy Sarda sheep belonging to 14 flocks with high somatic cell count scores, were studied. The flocks were located in diverse geographical areas of Sardinia, Italy. The aim of study was to assess the susceptibility of isolates to 13 antimicrobial agents, many of which are frequently used in mastitis therapy. Oxacillin was used for detecting methicillin-resistant S. epidermidis (MRSE) by disk diffusion test. Thirty-eight percent of the isolates (n = 50) were resistant to penicillin, 7.6% (n = 10) were resistant to tetracycline, and 2.3% (n = 3) were resistant to both penicillin and tetracycline (PTRSE). Two isolates were resistant to five antimicrobials including methicillin. Analysis of staphylococcal cassette chromosome mec (SCCmec) elements showed that both MRSE isolates harbored SCCmec type IVa. Based on pulsed-field gel electrophoresis (PFGE) typing by SmaI macrorestriction, S. epidermidis isolates were grouped into four clusters at 75% similarity level. The two multi-drug resistant MRSE isolates displayed distinct PFGE patters. This study indicates that S. epidermidis isolates from sheep milk samples may accumulate resistance markers for different antimicrobial agents. Furthermore, the occurrence of PTRSE and MRSE suggests to adopt adequate hygienic measures when handling animals with intramammary infections, in order to prevent spreading PTRSE and MRSE strains to humans through direct contact and/or consumption of contaminated food.  相似文献   

11.
The development of anthelmintic resistance has made the search for alternatives to control gastrointestinal nematodes of small ruminants imperative. Among these alternatives are several medicinal plants traditionally used as anthelmintics. This work evaluated the efficacy of Cocos nucifera fruit on sheep gastrointestinal parasites. The ethyl acetate extract obtained from the liquid of green coconut husk fiber (LGCHF) was submitted to in vitro and in vivo tests. The in vitro assay was based on egg hatching (EHT) and larval development tests (LDT) with Haemonchus contortus. The concentrations tested in the EHT were 0.31, 0.62, 1.25, 2.5 and 5 mg ml−1, while in the LDT they were 5, 10, 20, 40 and 80 mg ml−1. The in vivo assay was a controlled test. In this experiment, 18 sheep infected with gastrointestinal nematodes were divided into three groups (n = 6), with the following doses administered: G1—400 mg kg−1 LGCHF ethyl acetate extract, G2—0.2 mg kg−1 moxidectin (Cydectin®) and G3—3% DMSO. The worm burden was analyzed. The results of the in vitro and in vivo tests were submitted to ANOVA and analyzed by the Tukey and Kruskal–Wallis tests, respectively. The extract efficacy in the EHT and LDT, at the highest concentrations tested, was 100% on egg hatching and 99.77% on larval development. The parameters evaluated in the controlled test were not statistically different, showing that despite the significant results of the in vitro tests, the LGCHF ethyl acetate extract showed no activity against sheep gastrointestinal nematodes.  相似文献   

12.
This study assessed the effectiveness of a mutant strain of Toxoplasma gondii (RH strain) lacking the mic1 and mic3 genes (Mic1-3KO) against Toxoplasma abortion in sheep. Ewes were inoculated subcutaneously with 105 Mic1-3KO tachyzoïtes in three independent experiments. Following vaccination, Mic1-3KO induced a mild febrile response and serum IgG antibodies, which persisted throughout the experiments. Tissue cysts formed in the sheep, but were not, under our experimental conditions, infectious when given orally. Ewes were mated two months after vaccination and were orally challenged with the PRU strain of T. gondii at mid-gestation (400 oocysts in Experiments 1 and 2; 100 oocysts in Experiment 3). Challenge of vaccinated pregnant ewes resulted in a slight febrile response, whereas unvaccinated ewes developed a more severe, characteristic febrile response of longer duration. After challenge, all unvaccinated ewes aborted whereas 62%, 91% and 64% (Experiments 1, 2 and 3 respectively) of the lambs from vaccinated ewes were viable, with no clinical signs of infection. Mic1-3KO was as effective as S48, the strain used as a live vaccine for sheep (Toxovax®). A dose of 105 Mic1-3KO tachyzoites was sufficient to induce protection (versus a dose of 2 × 106). Both subcutaneous and intraperitoneal injections were effective. Moreover, preliminary results showed the potential of Mic1-3KO to reduce the development of tissue cysts in lambs born to vaccinated ewes. This study demonstrates that Mic1-3KO is a potent vaccine candidate.  相似文献   

13.
An outbreak of Toxoplasmosis in a colony of squirrel monkeys (Saimiri sciureus) in Israel is described. Serological, pathological, and molecular findings of monkeys, as well as rodents and pigeons from the vicinity are summarized. Seventy-nine percent (19/24) of monkeys were T. gondii seropositive at titer 1:16 whilst 4% (1/24) were also seropositive at titer 1:64 using the Modified Agglutination Test (MAT). Eighty four percent (21/25) of rats were positive at titer 1:16 and 8% (2/25) of rats were positive at titer 1:32. DNA amplification of a 529 bp repeated sequence of T. gondii was detected in the liver and lungs of all monkeys tested, 6/7 in myocardial extractions and 5/6 in brain extractions.  相似文献   

14.
The present study describes the occurrence of various gastrointestinal helminths, lungworms and liver flukes in Norwegian sheep and goats as assessed from faecal samples and post mortem examinations performed between 2007 and 2010. Faecal samples for gastrointestinal nematode egg counts were collected from 77 sheep flocks and 30 dairy goat flocks from three geographical regions in Norway. Additionally, thirty-two lambs and 16 adult goats were euthanized for necropsy examination and for identification of adult gastrointestinal nematodes and tapeworms, lungworms and liver flukes. The survey showed that there was a higher mean excretion of trichostrongyle eggs in sheep than in goats at the individual level (392 EPG vs. 154 EPG, p < 0.001). For both host species, the mean prevalence and intensity of excreted trichostrongyle eggs were significantly higher in the southern coastal region compared with the inland and northern regions (p < 0.001). Third stage larvae of Trichostrongylus/Teladorsagia, Haemonchus and Nematodirus type were the most prevalent ones in the coprocultures from sheep, whereas larvae of Trichostrongylus/Teladorsagia and Nematodirus type dominated in goats. The most prevalent gastrointestinal nematode species found at necropsy was Teladorsagia circumcincta (75.0 and 81.2% respectively in sheep and goats), while the largest mean worm burdens were recorded for Haemonchus contortus in sheep (724 ± 623) and T. circumcincta in goats (377 ± 529). Other gastrointestinal nematode species were present at low prevalence or in low numbers.  相似文献   

15.
The aim of this study was to carry out a seroepidemiological study of anti-T. gondii and anti-N. caninum antibodies in serum samples from sheep intended for human consumption in the Rondônia state, in the Western Brazilian Amazon, and identify possible risk factors associated with seropositivity. The analysis of the 616 sheep serum samples revealed animal-level seroprevalence of T. gondii in the order of 52.4 % and of N. caninum of 60.6 %. Prevalence of co-infections was 33.4 %. The herd-level seroprevalence was 100 % for both the parasites. Applying of multivariate logistic regression analysis, test of the association between seroprevalence of T. gondii infection and the potential predictors showed that feed, fetal malformation, abortion, neurological problems (lambs), presence of rodents were the significant (P < 0.05) predictors. The variables presence of rodents, cats, wild animals and main activity showed statistical association (P < 0.05) with the seroprevalence of N. caninum. Due to the high prevalence of T. gondii and N. caninum found in this study, the absence of specific slaughterhouses for sheep and raw or undercooked sheep meat for human consumption we concluded that sheep can represent an important source of infection for humans.  相似文献   

16.
In light of rapidly spreading triclabendazole resistance alternative fasciocidal drugs are urgently needed. Following up on promising results obtained with artemether in Fasciola hepatica infected sheep, we here report the efficacy and safety of artesunate in sheep with a natural F. hepatica infection. Artesunate was administered intravenously and intramuscularly, adverse events were monitored and drug efficacy was elucidated by means of faecal egg and worm burden reductions. A single 40 mg/kg intravenous dose of artesunate induced an egg count reduction of 68.9% and a worm burden reduction of 77.4%. Intramuscular artesunate at 40 mg/kg reduced faecal egg count and worm burden by 97.6% and 91.9%, respectively; whereas at 60 mg/kg it caused 93.2% and 87.1% reduction in faecal egg count and worm burden, respectively. Three sheep died 24-72 h post-treatment with a double dose of 40 mg/kg intramuscular artesunate, showing lethargy, sialorrhoea, reduced rumination and tremors. Egg and worm burden reductions of 93.3% and 83.9%, respectively, were calculated in the three surviving sheep. In conclusion, the interesting fasciocidal properties of artesunate in sheep warrant further investigations with an emphasis on toxicity studies.  相似文献   

17.
Objective was to investigate if trematode infections predispose ewes to mastitis and/or metritis. We used 80 trematode-infected ewes: primigravidae in group P-A and multigravidae in M-A remained untreated, primigravidae in P-B and multigravidae in M-B were drenched with netobimin and multigravidae in M-C were given rafoxanide. We collected faecal samples for parasitological examination, blood samples for β-hydroxybutyrate concentration measurement and uterine content, teat duct material and milk samples for bacteriological examination. We found significant differences in blood β-hydroxybutyrate concentrations between M-A, M-B and M-C during pregnancy (P ? 0.002). We did not observe significant differences between groups regarding development of metritis (P > 0.83). We found that for M-A, M-B and M-C ewes, respectively, median time to first case of mastitis was 5.75, 21 and 6.75 days after lambing (P = 0.003) and incidence risk of mastitis was 0.308, 0.069 and 0.222 (P = 0.047). We postulate that trematode infections predispose ewes to mastitis; perhaps, increased β-hydroxybutyrate blood concentrations adversely affect mammary cellular defences. This is the first report associating parasitic infections with mastitis in sheep.  相似文献   

18.
Small ruminant lentiviruses (SRLV), which belong to the Retroviridae family, infect goats and sheep worldwide. The aim of this study was to characterize the SRLV strains circulating in Slovenia, by phylogenetic analysis of two genomic regions, 1.8 kb gag-pol fragment and 1.2 kb pol fragment. The results of our study revealed that Slovenian SRLV strains are highly heterogeneous, with ovine strains belonging to genotype A and caprine strains to genotypes A and B. The closest relatives of sheep virus sequences from two flocks that clustered together (SLO 35, 36) were found to be in subtype A5. A cluster composed of four sheep virus sequences (SLO 31) was clearly divergent from all other subtypes in group A and could not be assigned to any of them. The virus sequences from one goat flock belonged solely to subtype B1, whereas virus sequences from more than one genotype were found to circulate within the other two goat flocks, belonging to subtype B1 (SLO 1 and SLO 37) and to genotype A (SLO 2 and 78–88 g). Two goat virus sequences (SLO 2) were found to belong to genotype A and could not be assigned to existing subtypes. One goat virus sequence (37–88 g) from flock 37 was clearly different from other sequences of this flock and was more closely related to genotype A sequences. We propose two new subtypes within genotype A, subtype A14 (SLO 2) and A15 (SLO 31).  相似文献   

19.
The long-term protective immunity of an inactivated mineral-oil adjuvanted Mycoplasma agalactiae vaccine was evaluated in sheep. The antigen suspension was emulsified with a mixture of three mineral oils (Montanide ISA-563, Marcol-52, Montane-80 at the ratio of 30%, 63%, and 7%, respectively). Twenty-two animals were divided in 2 groups (A and B) and immunised with two doses of the vaccine (group A, n = 14) or used as unvaccinated control (group B, n = 8). Five months after the second vaccination, seven animals of group A and four animals of group B were challenged by nasal route with M. agalactiae. The remaining seven vaccinated and four control animals were challenged intranasally eight months after vaccination. The vaccine was able to induce a full-protective immunity preventing the clinical signs of contagious agalactia and the infection by M. agalactiae in all groups of animals irrespective of the time of challenge after booster administration.  相似文献   

20.
Toxoplasmosis is an important cause of abortion in sheep and a zoonotic risk to humans, leading to significant hazards to health and to economic losses. This study examined the seroprevalence and associated risk factors for infection with Toxoplasma gondii in 379 sheep from 12 flocks in Rio de Janeiro state, Brazil. Using the modified agglutination test (MAT), 202 (53.3 %) of 379 were seropositive with titers of 1:25 in 65, 1:50 in 40, 1:100 in 23, 1:200 in 11, 1:400 in 36, 1:800 in 7, 1:1,600 in 1, and 1:3,200 or higher in 19 sheep. The most significant factors associated with T. gondii seropositivity in sheep were age, gender, and veterinary care. Finding of T. gondii antibodies in 97 of the 202 sheep in titers of 1:100 or higher is indicative of persistently infected animals. This high level of seropositivity requires urgent control measures to reduce impact on animal productivity and public health.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号