Evidence of Toxoplasma gondii Exposure in Boer Goat Herds in Missouri,USA

Limited data currently exist on the prevalence of Toxoplasma infections in goats in the USA. The objective of this pilot investigation was to determine the prevalence of Toxoplasma gondii antibodies in Boer goats raised in Missouri. Sera collected from 367 Boer goats in 24 herds were tested using a commercial latex agglutination assay. Evidence of T. gondii antibodies was present in 25 of the 367 goats, with titres of 1 : 32 in 4, 1 : 64 in 11, 1 : 128 in 5, 1 : 256 in 3 and 1 : 1024 in 2. Estimates for the apparent animal‐level and between‐herd prevalence were 6.8% (95% CI = 4.7–9.9%) and 41.7% (95% CI = 24.5–61.2%). These results confirm that Boer goats in Missouri are exposed to T. gondii and may constitute a public health risks.     

Antibody Prevalence and Risk Factors for Toxoplasma gondii Infection in Women from Multan,Pakistan

Toxoplasma gondii infections are prevalent in humans and warm‐blooded animals. Maternal infections during pregnancy may have devastating consequences for transplacentally infected neonates. This study was conducted to examine the seroprevalence of antibodies to T. gondii in pregnant women of childbearing age and determine risk factors associated with pregnancy history, pet ownership, social and cultural factors at Nishtar Hospital, Multan. Samples were collected from 403 women and examined using a commercially available enzyme‐linked immunosorbent assay (ELISA). The overall prevalence of antibodies to T. gondii was 17.6% (71) in the 403 samples collected from women. Antibodies to T. gondii were present in 19.4% (45) of 232 pregnant women and 15.2% (26) of the samples from 171 non‐pregnant women. This study identified miscarriage history, pet ownership, type of residence, marital status, source of drinking water and eating habits as significant (P < 0.05) risk factors associated with the presence of antibodies to T. gondii infection. Seroprevalence was not significantly different (P > 0.05) in women from different ethnic groups based upon lifestyle and culture.     

Prevalence of IgG Antibodies to Toxoplasma gondii in Veterinary and Undergraduate Students at Virginia Tech,Blacksburg, Virginia

Toxoplasma gondii is a globally distributed parasitic protozoan that infects humans and other warm‐blooded vertebrates. Felids are the only definitive host for T. gondii, and they excrete oocysts in their faeces. The national prevalence in humans is declining in the United States. This zoonotic organism is of particular interest due to its importance in pregnant women, in individuals with altered immune systems, and in reactivated ocular infections. Exposure to the parasite in humans is usually associated with consumption of raw or undercooked meat or by accidental ingestion of oocysts. It was hypothesized that veterinary students would have a greater chance at exposure to the parasite than an average population of undergraduate students due to increased contact with cats who are infected. A commercially available ELISA was used to examine serum samples from 336 students (252 veterinary students and 84 undergraduate students) at Virginia Polytechnic Institute and State University and the Virginia‐Maryland Regional College of Veterinary Medicine for serum IgG antibodies to T. gondii antigen. The prevalence of T. gondii in these subjects was 5.6% in veterinary school students (n = 252) and 2.4% in undergraduates (n = 84). There was no significant difference (P > 0.05) in the prevalence of T. gondii antibodies in veterinary versus undergraduate students. The overall prevalence of 4.8% in all students in this study reflects the continuing decline of antibodies to T. gondii in humans in the United States.     

Detection of Zoonotic Protozoa Toxoplasma gondii and Sarcocystis suihominis in Wild Boars from Spain

Food safety regulations require the control of the presence of protozoa in meats destined for human consumption. Wild boar (Sus scrofa) meat may constitute a source of zoonoses. A 23.8% (688/2881) seroprevalence of anti‐Toxoplasma gondii antibodies and 72.2% (662/910) Sarcocystis sarcocysts prevalence were detected among wild boars hunted in Southwestern areas of Spain. Identity of Sarcocystis spp. was performed by RFLP‐PCR and sequencing, detecting S. miescheriana (7/8) and the zoonotic S. suihominis (1/8). Risk assessment studies of these coccidian in meats destined to human consumption are needed.     

Toxoplasma gondii in Ireland: Seroprevalence and Novel Molecular Detection Method in Sheep,Pigs, Deer and Chickens

Toxoplasma gondii is among the most studied parasites worldwide but there is not much information about it published in Ireland. The objectives of this study were to determine the seroprevalence of T. gondii in sheep, pigs, deer and chickens and the molecular detection of T. gondii DNA in muscle tissue. Serum samples were collected from these species at the time of slaughter at Irish abattoirs during 2007 and tested for anti‐T. gondii antibodies using a commercial semi‐quantitative latex agglutination test. Antibodies (titre ≥1 : 64) were found in 36% (105/292) sheep, 4.7% (15/317) pigs and 6.6% (23/348) deer. In chickens, 18% (65/364) had antibody titres, ranging between 1 : 5 and 1 : 1024. Significant (P ≤ 0.05) age‐related differences in seroprevalence were found in adult sheep (58.1%) and pigs (23.1%). Significant gender differences in seroprevalence was also found in sheep with more females (43%) than males (22.4%) being positive. However, when adjusted for age through logistic regression gender was no longer significant. Seroprevalence was also evaluated on farm locations grouped to NUTS level 3, but the prevalence was too low to draw any statistical conclusions. Using a nested PCR, the presence of T. gondii DNA was detected in diaphragm samples from 3.6% (3/83) sheep, 13.0% (3/23) pig and 4.2% (3/71) deer. Meat digestion liquids from a Trichinella spp. survey in pigs were also used for the first time to detect T. gondii. Toxoplasma gondii DNA was detected in 50% (10/20) of pooled samples. This is the first in depth study of T. gondii seroprevalence in animals in Ireland and a novel method, using digestion liquid from pooled diaphragm samples, for PCR detection in pigs is described.     

免疫学技术在弓形虫检测方面的研究概况

弓形虫病是世界分布最广泛的一种人兽共患病,此病在温暖潮湿的地区感染率极高,所以建立高效敏感的检测方法是非常必要的。目前,国内检测弓形虫病的技术有多种,其中以免疫学技术为主。虽然病原学检测方法的敏感性高,特异性强,但其成本高,对人体会产生严重的副作用,所以并不适宜推广。近年来,通过对弓形虫表面抗原的大量研究,检测弓形虫病的免疫学技术也有了显著提高。从敏感性差、操作复杂到现在的特异性强、快速简便,从单一抗原的检测到现在的多表面抗原的检测,无疑为检测弓形虫带来了新的思路。论文主要对检测弓形虫的ELISA、改良凝集试验以及化学发光免疫分析的最新进展进行了综述。     

屠宰羊弓形虫感染情况调查

为了保障羊肉制品的生物安全,对屠宰羊进行弓形虫感染情况调查以及对羊肉进行弓形虫检测。采用间接血凝试验,对677份屠宰羊的血清进行了弓形虫抗体检测。结果显示,弓形虫抗体阳性有47份,阳性率为6.9%。     

Seroprevalence of Toxoplasma gondii in wild boar and deer in Brandenburg,Germany

Consumption of game in Germany has increased during the past 10 years. Wild boar (Sus scrofa), roe deer (Capreolus capreolus) and red deer (Cervus elaphus) are the most frequently hunted and consumed game animals in Germany, yet information on the occurrence of zoonotic pathogens in these animal species is scarce. To better estimate the public health risk emanating from handling and consumption of game, this study investigated seroprevalences of Toxoplasma gondii in game hunted in the German federal state of Brandenburg during two hunting seasons from 2017 to 2019. Toxoplasma gondii‐specific antibodies were detected in 24.4% (44/180, 95% CI: 18.4%–31.4%) of wild boar, 12.8% (16/125, 95% CI: 7.5%–20%) of roe deer and 6.4% (3/47, 95% CI: 1.3%–17.5%) of red deer using a commercial ELISA kit. Seroprevalences were similar in the two hunting seasons. Correlation between sex and seropositivity could not be observed. A rise in seroprevalence was seen with increasing age in all studied game species. Observed seroprevalences suggest that T. gondii is endemic in the sylvatic environment in the German federal state of Brandenburg and imply that game could represent a relevant source for human T. gondii infection.     

Keratoconjunctivitis associated with Toxoplasma gondii in a dog

A 12-year-old Pug presented with a 3-mm corneal mass OD. The dog was currently being treated for keratoconjunctivitis sicca (KCS) and pigmentary keratitis OU. A superficial keratectomy followed by cryotherapy was performed OD. A histopathologic diagnosis of epithelial dysplasia and suppurative keratitis was made and the lesion resolved. Two months later, a yellow/tan conjunctival mass, diffuse chemosis and conjunctival thickening was discovered OD. Necrotizing conjunctivitis with protozoal parasites was diagnosed with histopathology. Complete blood count and a serum biochemistry panel were normal. Neospora caninum and Toxoplasma gondii titers were negative. The conjunctivitis resolved after a 6-week course of oral clindamycin. Two months later, the patient presented with a similar conjunctival mass OS. Toxoplasma gondii was confirmed as the etiologic agent with immunohistochemical staining. Repeat T. gondii titers were negative. Oral clindamycin was re-instituted. The corneal biopsy was re-reviewed and protozoal organisms were discovered. Three months later, a recurrence was suspected and oral ponazuril was initiated for 28 days. There has been no evidence of recurrence since this treatment. Ocular toxoplasmosis is rare in the dog but reports have included episcleritis, scleritis, retinitis, anterior uveitis, ciliary epithelium hyperplasia, optic neuritis and polymyositis. To our knowledge, this is the first confirmed report of toxoplasmosis causing only corneal and conjunctival disease in the dog. We hypothesize that these localized lesions may be associated with topical immunomodulating therapy for KCS. Toxoplasmosis should be considered as a differential for canine conjunctivitis and corneal disease and has the potential to manifest in one or both eyes.     

弓形虫环介导等温扩增快速检测方法的建立

为了建立弓形虫的快速检测方法,本研究建立了一种灵敏、特异、快速的分子生物学检测方法——环介导等温扩增技术(LAMP)。用10倍系列稀释的DNA样品对该检测方法的灵敏度进行了测试,同时通过对扩增产物做内切酶验证;为证明LAMP技术的特异性,对新孢子虫、附红细胞体、瑟氏泰勒虫等病原体进行检测。结果显示:利用LAMP技术成功检测到弓形虫基因区,此方法的灵敏度可达到能检测5个拷贝DNA分子水平,酶切分析结果正确,并且特异性强,对新孢子虫、附红细胞体、瑟氏泰勒虫等病原体检测均为阴性。说明LAMP技术可应用于弓形虫的快速检测。     

A Brief History and Overview of Toxoplasma gondii

Toxoplasma gondii was discovered by scientists working in North Africa and Brazil around 100 years ago. The parasite has since been found to be capable of infecting all warm‐blooded animals including humans making it one of the most successful parasitic organisms worldwide. The pathogenic potential of T. gondii was recognized in the 1920s and 1930s, in congenitally infected children presenting with the classic triad of symptoms, namely hydrocephalus, retinochoroiditis and encephalitis. In addition, around the same time T. gondii parasites were found to be associated with severe intraocular inflammation. In the 1980s, T. gondii emerged as a major cause of death in patients with acquired immunodeficiency syndrome, illustrating the importance of the immune system in controlling T. gondii infection. T. gondii was reported as a major cause of abortion in sheep in New Zealand in the 1950s, which raised questions about potential new transmission routes for the parasite. The discovery of the cat as the definitive host in the 1960s was a very important finding as it helped to complete our understanding of the parasite’s life cycle, and the oocyst stage of T. gondii shed in the faeces of infected cats was found to be an important source of infection for many intermediate hosts and helped to explain infection in herbivorous animals and people with a vegetarian diet. In addition, this stage of the parasite was very robust and could survive in the environment, depending on the climatic conditions, for up to 12–18 months. Knowledge of the parasite’s lifecycle, transmission routes, risk groups and host immune responses has helped in the development of strategies to control the disease, reduce transmission of the parasite and limit environmental contamination.     

弓形虫微线体蛋白研究新进展

微线体蛋白(microneme protein,MIC)是由位于弓形虫前端的微线体(microneme)分泌产生的,具有识别、黏附与侵染宿主细胞的性质。近年来研究结果证明,弓形虫的多种微线体蛋白在侵染宿主的过程中发挥重要作用,并且可以作为抗弓形虫病的疫苗候选分子。作者对目前研究较多的弓形虫微线体蛋白进行综述,为弓形虫疫苗的研究提供理论依据。     

弓形虫胚层发育相关蛋白的原核表达及免疫原性研究

试验旨在研究弓形虫胚层发育相关蛋白（TgERP）的免疫原性,以弓形虫RH株的基因组DNA为模板,扩增TgERP基因,将其连接于表达载体pET-30a(+)后,转化至Escherichia coli BL21（DE3）感受态细胞进行IPTG诱导表达,应用Western blotting对重组蛋白的反应原性进行分析,并用纯化后的TgERP蛋白免疫新西兰大白兔,制备多克隆抗体。结果显示,在37 ℃条件下用1.0 mmol/L IPTG诱导6 h表达可溶性TgERP蛋白的量最大。SDS-PAGE结果显示,目的蛋白分子质量为16.7 ku,以可溶形式表达,纯化后蛋白条带单一。经Western blotting分析,TgERP蛋白有较好的反应原性;制备的多克隆抗体效价较高,可达1∶51200,表明该蛋白具有较好免疫原性。提示,TgERP蛋白可作为血清学诊断方法的候选抗原和弓形虫病疫苗的候选分子,为建立弓形虫新型诊断方法和研制新型弓形虫疫苗奠定了基础。     

弓形虫急性感染与小鼠妊娠失败相关性研究

研究弓形虫感染对小鼠妊娠的影响。用免疫组织化学方法测定子宫部分免疫细胞,用酶联免疫吸附法测定子宫匀浆中肿瘤坏死因子 α(TNF α)和白介素 10(IL 10)的含量。发现孕0天和孕6天接种弓形虫,小鼠全部流产。感染组子宫内膜中仅见少量CD8+T淋巴细胞。对照组未见阳性细胞。F4/80+巨噬细胞在感染组小鼠子宫内膜中大量存在。对照组仅见少量F4/80+细胞。细胞因子测定结果表明,TNF α弓形虫感染组子宫匀浆中含量高达76 862±30 354pg/mg蛋白,显著高于正常妊娠7天时小鼠子宫中TNF α的含量(P<0 01)。结果提示,已妊娠母鼠感染弓形虫可引发流产,并与子宫胎儿界面的TNF α分泌增多有关。孕0天感染,孕鼠子宫匀浆上清液中IL 10含量平均值为19 696±9 811pg/mg蛋白,显著低于对照组(48 856±16 518pg/mg,P<0 05)。孕6天感染,子宫匀浆IL 10含量与对照组比较差异不显著(P>0 05)。     

桧烯抗弓形虫活性的体外评价

本研究旨在筛选具有抗弓形虫活性的萜类化合物,并进行体外活性评价。对26个萜类化合物进行体外抗弓形虫增殖作用的筛选,采用CCK-8法确定活性化合物对Vero细胞的毒性和安全浓度,Giemsa染色进一步确定对弓形虫的活性,通过细胞免疫荧光、Giemsa染色和生物化学发光法评价活性化合物对弓形虫的体外活性。结果表明,26个萜类化合物中,桧烯对弓形虫有显著的活性,桧烯对RH-2F的IC₅₀为90.76 μg·mL^-1,Giemsa染色和细胞免疫荧光的结果表明,桧烯对细胞内的两种弓形虫虫株都有显著的抗增殖作用,并且对弓形虫的入侵有极显著的抑制作用（P<0.001）。综上表明,桧烯对弓形虫的入侵和细胞内增殖具有显著的抑制作用,可作为潜在的抗弓形虫先导化合物。     

弓形虫蛋白质翻译后修饰研究进展

弓形虫是一种复杂的单细胞原生动物寄生虫,通过入侵宿主细胞、分裂和诱导宿主细胞破裂等一系列的过程,在温血动物体内进行增殖。弓形虫的生物学特征受基因组、表观遗传及转录等多种因素的调控。蛋白质翻译后修饰（protein post-translational modifications,PTMs）,如磷酸化、泛素化、巴豆酰化、棕榈酰化、琥珀酰化、乙酰化、甲基化、糖基化和二羟基异丁酰化等,是弓形虫调节对细胞外刺激的反应和生命周期转变的主要机制之一。弓形虫蛋白质翻译后修饰通过改变靶蛋白的定位、结构、活性、蛋白质-蛋白质相互作用等增加蛋白质的复杂性和多样性,从而在虫体生命周期的任何时间点都可以发挥至关重要的作用。在这篇综述中,作者重点对弓形虫蛋白质翻译后修饰进行简要总结,以期为深入研究弓形虫的生物学特征奠定基础。     

Seroprevalence of Bartonella species,Coxiella burnetii and Toxoplasma gondii among patients with hematological malignancies: A pilot study in Romania

Patients receiving immunosuppressive cancer treatments in settings where there is a high degree of human–animal interaction may be at increased risk for opportunistic zoonotic infections or reactivation of latent infections. We sought to determine the seroprevalence of selected zoonotic pathogens among patients diagnosed with haematologic malignancies and undergoing chemotherapeutic treatments in Romania, where much of the general population lives and/or works in contact with livestock. A convenience sample of 51 patients with haematologic cancer undergoing chemotherapy at a referral clinic in Cluj‐Napoca, Romania, was surveyed regarding animal exposures. Blood samples were obtained and tested for evidence of infection with Bartonella species, Coxiella burnetii and Toxoplasma gondii, which are important opportunistic zoonotic agents in immunocompromised individuals. 58.8% of participants reported living or working on a farm, and living or working on a farm was associated with contact with livestock and other animals. 37.5% of participants were IgG seroreactive against one or more of five Bartonella antigens, and seroreactivity was statistically associated with living on farms. Farm dwellers were 3.6 times more likely to test IgG seroreactive to Bartonella antibodies than non‐farm dwellers. 47.1% of the participants tested T. gondii IgG positive and 13.7% tested C. burnetii IgG positive, indicating past or latent infection. C. burnetii IgM antibodies were detected in four participants (7.8%), indicating possible recent infection. These results indicate that a large proportion of patients with haematologic cancer in Romania may be at risk for zoonotic infections or for reactivation of latent zoonotic infections, particularly with respect to Bartonella species. Special attention should be paid to cancer patients' exposure to livestock and companion animals in areas where much of the population lives in rural settings.