旋毛虫在感染肠道期诱导宿主免疫排虫反应的研究进展

旋毛虫病是一种以旋毛虫(Trichinella spiralis)为病原的人畜共患寄生虫病。旋毛虫主要侵袭宿主的肠道和肌肉组织,其中旋毛虫感染肠道期指旋毛虫成虫期,该期是旋毛虫侵袭宿主的关键阶段,决定了旋毛虫在宿主体内生活史的完整性。旋毛虫在宿主肠道的寄生会引发机体肠道损伤,机体通过排虫反应将其排出体外。排虫反应是多种因素相互调节的结果,即通过宿主肠道上皮细胞分泌黏蛋白和增加肠道平滑肌蠕动收缩能力来促进肠道上皮细胞中旋毛虫的排出,二者受体液免疫与细胞免疫的共同调节。笔者从宿主感染旋毛虫后发生的肠道病变、分泌黏蛋白、肠道平滑肌收缩能力增强和免疫调节方面进行综述,旨在为旋毛虫感染肠道期的排虫机制研究提供思路。     

不同消化时间对肌旋毛虫感染活性影响

<正>旋毛虫是毛形科(Trichinella)的旋毛形线虫(Trichinella spiralis),寄生于宿主动物引起疾病。是一种重要的人兽共患病。成虫寄生于动物的肠腔,幼虫寄生于动物的横纹肌内,其主要的宿主动物为猪、犬、鼠类、狐狸、野猪及人等;旋毛虫病的自然感染是由于宿主食入了含有旋毛虫活幼虫囊包的肉类及其制品,通过这种方式感染的幼虫为不脱囊幼虫;动物实验中常用人工消化法分离旋毛虫幼虫,以人工灌胃进行感染,这种方式感染的幼虫已脱去囊包(脱囊幼虫)。人工消化法既用于幼虫检查,也是收集幼虫     

猪旋毛虫的寄生和鉴定

旋毛虫病是人畜共患的严重寄生虫病之一,对人危害极大。在自然环境下,旋毛虫病见于猪、大鼠、小鼠、狗、猫及多种野兽。牛、羊、马和禽类在本病的播散中不起作用,主要宿主是猪、狗、鼠类和人。旋毛虫病在欧、美、亚、非许多国家均有报道,有的国家曾一度酿成严重的人畜共患疾病。１猪旋毛虫的寄生１．１旋毛虫病的临床表现虽然旋毛虫病引起的临床反应,随宿主种类、个体情况和旋毛虫品系的不同而异,但本病的严重程度总是与食入的旋毛虫数量有关。１．１．１猪旋毛虫病按照旋毛虫在宿主体内的发育阶段,可分为三个时期：肠内期、肌内期和…     

猪肌旋毛虫生活阶段与形态变化

前言旋毛虫是一种很细小的线虫,迄今为止仅知一个种,却广泛传播于陆地哺乳动物,其整个生活史只在单个宿主体内进行,成虫阶段寄生于宿主肠道,称为肠旋毛虫,幼虫阶段寄生于宿主肌肉内,称为肌旋毛虫。罹虫尸肉是主要的传染源,猪、犬、鼠     

旋毛虫病的检验及卫生处理

旋毛虫病是指旋毛线虫在人或动物肠道内寄居,它的幼虫在宿主横纹肌中寄生,导致疾病。该疾病通过含旋毛虫的肉类传播给人类,人因生食或未煮熟含有活的旋毛虫幼虫而感染。近年来,云南省昆明市禄劝县动物卫生监督所逐渐加大了对该病的检验和防治力度,以保障人们的食品安全。     

猪旋毛虫病的防治

<正>猪旋毛虫是人畜共患寄生虫病,是由毛行科旋毛虫的成虫寄生在小肠,幼虫寄生在横纹肌所引起。旋毛虫可以感染猪、犬、猫、鼠类等多种哺乳动物,为宿主寄生虫。含有肌肉旋毛虫的肉屑或者鼠类被猪吞食可引起感染。人使用了未煮熟的含有旋毛虫包囊的猪肉而引起感染发病。笔者在诊疗过程中收治一例猪旋毛虫,报告如下:1发病基本情况和感染特点我区乐甲乡乐甲村李某饲养散养猪2头,发现初期病猪体温升高,畜主给以抗生素治疗,效果不明显,死亡1头,来     

旋毛虫种属分布研究进展

旋毛虫自发现以来,已有180年的历史,研究人员通过对亚洲和欧洲的共110个旋毛虫地理隔离株碱基进行分析发现,欧洲地理隔离株比亚洲地理隔离株的一致性更高,并且发现不同旋毛虫对动物的感染具有一定的异嗜性。随着Trichinella patagoniousis的发现,使得旋毛虫种属已扩大到了9个种和3个分类地位尚不明确的基因型,又进一步扩充了旋毛虫的数据库。不同种旋毛虫宿主和分布范围在不断扩大,已经涉及到55个国家及150多种哺乳动物、鸟类和爬行动物感染旋毛虫,诸多因素均表明,旋毛虫严重威胁着人类健康。明确旋毛虫的种类、宿主及其地理分布对旋毛虫病的防控具有重要意义。     

洛阳市猪旋毛虫病快速检测技术推广应用报告

旋毛虫病是由旋毛虫的幼虫和成虫引起的一种人畜共患寄生虫病,分布于世界各地,传播途径复杂,宿主动物种类繁多。该病是由毛形目、毛形科的旋毛形线虫寄生于人畜体内所引起的疾病。成虫寄生于肠管,又称肠旋毛虫。幼虫寄生于横纹肌,又称肌旋毛虫。据统计,包括猪、犬、猫、鼠、狐狸、狼、貂等120多种哺乳动物和人均可感染旋毛虫。患病动物轻则肌肉僵硬,咀嚼困难,运动障碍,生长迟缓,重则卧地不起,导致死亡。人感染后引起发热,肠炎,肌肉疼痛,咀嚼和呼吸困难,食欲不振,显著消瘦,严重时多因呼吸肌、心肌及其他脏器的病变和毒素的作用等而引起死亡。…     

旋毛虫各隔离种的感染性和分布规律的研究

旋毛虫病(Trichinellosis)是由旋毛虫寄生于宿主体内而引起的一种重要的人兽共患寄生虫病,对人和家畜健康危害很大.成虫寄生于肠腔,称为肠型旋毛虫;幼虫寄生于同一动物的横纹肌内,称为肌型旋毛虫.其主要的宿主动物是猪、犬、猫、鼠类、狐狸、野猪及人等.由于人食入含有幼虫包囊的生猪肉而感染旋毛虫病,可使人死亡,因此旋毛虫病原检测在肉品卫生检验上特别重要.     

旋毛虫Ts43基因在各感染时期的转录水平上差异表达

旋毛虫(Trichinella spiralis)是一种感染宿主骨骼肌细胞的寄生虫.旋毛虫新生蚴钻入宿主骨骼肌细胞后,会导致其去分化,从而改造肌细胞,使之形成保姆细胞(nurse cell,NC).     

非特异性效应细胞抗旋毛虫感染作用机制研究进展

先天性免疫细胞由树突细胞、肥大细胞、巨噬细胞、嗜酸粒细胞和天然杀伤细胞组成。旋毛虫入侵机体后,这些先天性免疫细胞作为前沿免疫防御系统,首先快速发挥各自作用,并诱发更加有效的Th2型免疫应答,在保护机体免受重大损伤、抵制并排除旋毛虫方面起着必不可少的作用。论文详细综述了旋毛虫感染机体后,机体先天性免疫细胞的作用方式、作用机制以及相关免疫分子的研究进展。     

寄生虫抗肿瘤研究进展

虽然旋毛虫抗肿瘤的分子机制仍不清楚,但旋毛虫具有抗肿瘤的效应却已被许多实验所证实。小鼠感染旋毛虫后对肿瘤细胞在体内的增殖或对移植进体内的肿瘤生长的抑制作用,其可能的机理是旋毛虫感染机体后激发宿主免疫网络系统促使机体产生多种免疫活性细胞因子,发挥特异性和非特异性抗肿瘤免疫功能;或者是由于寄生虫本身就具有能够分泌排泄一些抗肿瘤活性物质而发挥抗肿瘤效应;或者是由于寄生虫感染诱导肿瘤的基因表达发生变化而产生了抗肿瘤的效应。     

Intestinal phospholipase B activity in swine inoculated with Trichinella spiralis

Trichinella spiralis was studied in outbred swine to determine whether infection would cause an increase in intestinal phospholipase B (EC 3.1.1.5) activity and in number of peripheral eosinophils. Intestinal phospholipase B activities increased and were accompanied by eosinophilia. The response was similar to that found in rodents infected with helminth parasites, thus demonstrating that phospholipase B is not unique to rodent models and is probably part of the complex immune response of the host in defense against parasitic infections.     

Larval viability and serological response in horses with long-term Trichinella spiralis infection

The horse is considered an aberrant host for the nematode parasite Trichinella spiralis, and many aspects of the biology and epidemiology of Trichinella infection in the horse are poorly understood. It has been reported that experimentally-infected horses produce a transient serological response to infection and that muscle larvae are cleared more rapidly than in parasite-adapted hosts such as the pig and humans. However, limited numbers of animals have been studied, and both the longevity of larvae in horse musculature and the immune response to Trichinella larvae remain unclear. In this study, we infected 35 horses with 1000, 5000, or 10,000 T. spiralis muscle larvae and followed the course of infection for 1 year, assessing larval burdens in selected muscles, the condition and infectivity of recovered larvae, and the serological response of infected horses. The results demonstrated that T. spiralis establishes infection in horses in a dose dependent manner. Anti-Trichinella IgG antibodies peaked between weeks 6-10 post-inoculation. Viable, infective larvae persisted in horse musculature for the duration of the study (12 months), and exhibited no apparent reduction in muscle burdens over this period. Encapsulated larvae showed no obvious signs of degeneration in histological sections. Larval capsules were surrounded by infiltrates consisting of mature plasma cells and eosinophils. Macrophages were notably absent. Given the lack of a detectable serological response by 26 weeks p.i. and the persistence of infective muscle larvae for at least 1 year, parasite recovery methods are currently the only suitable detection assays for both meat inspection and epidemiological studies of Trichinella infection in the horse.     

Host diversity and biological characteristics of the Trichinella genotypes and their effect on transmission

The host spectra and biological diversity of the Trichinella genotypes are reviewed. While all genotypes appear to reproduce equally well in carnivore hosts, their infectivity and persistence in omnivores and herbivores show remarkable differences. Most of the genotypes found in wildlife have low infectivity for pigs and some persist only for a few weeks; in herbivores this tendency is even more profound, but malnourished, environmentally stressed, or otherwise immuno-suppressed hosts are likely to be more susceptible to Trichinella genotypes that would otherwise cause no, or only low level infection in that particular host species. In the domestic habitat (e.g. domestic pig farms), Trichinella spiralis is found almost exclusively, but in the sylvatic habitat the other Trichinella genotypes have found individual ecological niches. Thus, when environmental stress is limited in the domestic habitat, the high reproductive capacity of T. spiralis has a selective advantage, but in nature, the tolerance of other (sylvatic) genotypes to high and low temperatures and decomposition of host tissue might be more important. Parasite distribution according to muscle appear to be independent of the genotype of Trichinella and predilection sites are primarily determined by host species and secondarily by the age and level of infection. The biological diversity of the Trichinella genotypes should definitely be considered when planning experimental studies, as the uniform high infectivity of all genotypes in carnivores probably make them more suited for comparative studies than rodents.     

Profiling excretory/secretory proteins of Trichinella spiralis muscle larvae by two-dimensional gel electrophoresis and mass spectrometry

Infection of mammalian skeletal muscle with the intracellular parasite Trichinella spiralis results in profound alterations in the host cell and a realignment of host cell gene expression. The role of parasite excretory/secretory (E/S) products in mediating these effects is unknown, largely due to the difficulty in identifying and assigning function to individual proteins. In this study, we have used two-dimensional electrophoresis to analyse the profile of muscle larva excreted/secreted proteins and have coupled this to protein identification using MALDI-TOF mass spectrometry. Interpretation of the peptide mass fingerprint data has relied primarily on the interrogation of a custom-made Trichinella EST database and the NemaGene cluster database for T. spiralis. Our results suggest that this proteomic approach is a useful tool to study protein expression in Trichinella spp. and will contribute to the identification of excreted/secreted proteins.     

Comparative assessment of a double antibody enzyme immunoassay test kit and a triple antibody enzyme immunoassay for the diagnosis of Trichinella spiralis spiralis and Trichinella spiralis nativa infections in swine.

Enzyme immunoassays using the triple antibody enzyme linked immunosorbent assay (ELISA) with both Trichinella spiralis spiralis and T. spiralis nativa excretory-secretory (ES) antigens and a commercial Trichinella spiralis enzyme immunoassay test kit were carried out on sera from pigs that were infected with light, moderate and high doses of infective T. spiralis spiralis and T. spiralis nativa respectively. Seroconversion occurred in all pigs given infective Trichinella larvae although no trichinae were recovered from pigs given T. spiralis nativa larvae and examined between days 92 and 99 postinfection by pepsin digestion. Anti-Trichinella antibodies were detected in pigs infected with T. spiralis spiralis and T. spiralis nativa by ELISA using either the homologous or heterologous ES antigen. The commercial Trichinella spiralis enzyme immunoassay test kit also detected anti-Trichinella antibodies in both the T. spiralis spiralis and T. spiralis nativa infected pigs. The commercial test kit did not appear to be as sensitive as the triple antibody ELISA since it usually took two to three days longer for seroconversion to be detected by the former procedure. Finally seroconversion occurred more rapidly in swine infected with T. spiralis spiralis than with pigs receiving comparable doses of T. spiralis nativa.     

Factors affecting the flow among domestic, synanthropic and sylvatic cycles of Trichinella

Nematodes of the genus Trichinella are maintained in nature by sylvatic or domestic cycles. The sylvatic cycle is widespread on all continents, from frigid to torrid zones, and it is maintained by cannibalism and scavenging behavior of carnivores. Trichinella is primarily a parasite of carnivorous mammals, although one non-encapsulated species, Trichinella pseudospiralis, has also been detected in birds. The anaerobic metabolism of larvae in nurse cells allows their survival in extremely decayed meat. Encapsulated larvae in the decomposing carcass function similarly to the species-dispersing population of eggs or larvae of other nematodes, suggesting that the natural cycle of Trichinella includes a free-living stage when the parasite is no longer protected by the homeothermy of the host. Consequently, environmental temperature and humidity play an important role in the transmission of Trichinella among wildlife. Of the 10 recognized genotypes of Trichinella, only Trichinella spiralis is transmitted and maintained in a domestic cycle, although it can be present also in wildlife. All other genotypes (Trichinella nativa, Trichinella britovi, T. pseudospiralis, Trichinella murrelli, Trichinella nelsoni and Trichinella papuae, Trichinella T6, T8, and T9) are transmitted and maintained only in a sylvatic cycle. This generalization does not preclude sylvatic species of Trichinella from invading the domestic habitat, and T. spiralis may return to this habitat when humans fail in the management of wildlife and domestic animals. However, the presence of sylvatic genotypes of Trichinella in the domestic habitat represents a "dead-end" for the sylvatic cycle. Synanthropic animals (rats, foxes, mustelids, cats, dogs, etc.) contribute to the flow of sylvatic Trichinella genotypes from wildlife to domestic animals and of T. spiralis from domestic to sylvatic animals. Furthermore, human behavior not only influences the transmission patterns of Trichinella genotypes in the domestic habitat, but also it can contribute to the transmission and spread of this infection among wildlife, for example by improper hunting practices.     

Influence of adjuvant formulation on the induced protection of mice immunized with total soluble antigen of Trichinella spiralis

Vaccination of pigs against the helminth nematode Trichinella could be a good alternative to prevent the risk of human infection. In order to develop an efficient and safe vaccine, the choice of the adjuvant is an important issue. In this study, two adjuvants were selected to prepare vaccines based on total soluble Trichinella spiralis muscle larvae (ML) antigen: Montanide ISA 70 water in oil emulsion and Montanide IMS nanoparticles. Aluminium hydroxide was used as a reference adjuvant. The immune response was checked by ELISA of parasite antigen specific IgG1 and IgE. Finally, protection induced in vaccinated mice was measured after a T. spiralis challenge by counting ML burdens. The results clearly showed an impact of adjuvants on the specific IgG1 and IgE antibody responses against T. spiralis. Differences were observed between the rates of protection induced according to the type of formulation, although the three adjuvants tested were able to enhance the humoral immune response. This work demonstrated the need to use an adjuvant to obtain a specific IgG1 and IgE responses directed against the total soluble extract of T. spiralis.     

Immunity in swine inoculated with larvae or extracts of a pig isolate and a sylvatic isolate of Trichinella spiralis

Inoculation of swine with a sylvatic isolate of Trichinella spiralis, designated T s nativa, resulted in low numbers of muscle larvae, compared with muscle larvae accumulation in swine inoculated with a pig type of T s spiralis. Despite low infectivity of T s nativa for swine, primary inoculation resulted in high levels of immunity against challenge infection with T s spiralis. This immunity was expressed in accelerated expulsion of challenge adults from the intestine and reduced numbers of muscle larvae. Pigs inoculated with T s nativa developed cellular and humoral responses similar to those in pigs inoculated with T s spiralis. However, in immunoblots, sera from pigs inoculated with T s nativa recognized additional proteins in muscle larvae excretory-secretory (ES) products, compared with sera from pigs inoculated with T s spiralis. Active immunization of pigs with ES products from T s nativa resulted in numerically higher, but not significantly different levels of immunity, compared with pigs immunized with ES from T s spiralis. The highest levels of immunity were obtained in pigs immunized with a T s spiralis newborn larval extract. The combination of ES products and newborn larval extract did not result in additive levels of immunity. These results indicate that the major immune effector response to Trichinella sp in pigs is against the newborn larvae, regardless of the genetic type of Trichinella sp.