佐剂在抗蜱疫苗中的应用

使用抗蜱疫苗是防治蜱类的有效策略之一,而单抗原的免疫原性较低,需要添加佐剂增强其免疫原性。佐剂是疫苗中增强免疫原性的化合物,添加入疫苗中可诱导宿主产生更持久、更广泛的免疫反应。文章简要介绍了抗蜱疫苗中常用的弗氏佐剂、Montanide ISA佐剂、单磷酰脂质A佐剂、细胞因子佐剂和聚阳离子肽IC31佐剂,并对各种佐剂的作用机制及应用效果进行归纳总结,以期为深入揭示佐剂作用机制提供科学依据,为后续研制抗蜱疫苗提供参考。     

非洲猪瘟病毒传播媒介研究进展及猪场高效消毒剂的选用

非洲猪瘟因其致死率高和传播速度快，迅速扩散全国，给养猪业带来巨大经济损失。非洲猪瘟病毒结构独特、抵抗力强，而且我国具有其高适生存的钝缘软蜱，因此猪场生物安全防控应关注病毒和媒介两个方面，一方面要采取合适的消毒防控措施以及选择非洲猪瘟病毒专用的高效消毒剂，另一方面要加强对传播媒介的监测，未雨绸缪地研究杀虫剂和抗蜱疫苗。主要综述了非洲猪瘟病毒的传播媒介，包括中间宿主钝缘软蜱和一些储存宿主，以及针对病毒和这些传播媒介的消毒剂和杀虫剂的研究进展，以期为打好猪场生物安全防控的攻坚战和未来生猪的复养提供理论依据。     

牛节肢动物寄生虫病的诊断与防治方法

牛皮蝇、牛蜱、牛虱、牛螨等节肢动物是许多病原体的传播媒介和保虫宿主,它们的叮咬或在牛体表寄生可引起多种疾病,主要对如何诊断和防治牛皮蝇、牛蜱、牛虱等节肢动物引起的寄生虫病作一介绍,以期为养殖同仁提供参考。     

蜱对宿主免疫调节作用的研究进展

蜱作为人与动物疾病的第二大传播媒介,已受到人们的广泛关注。目前,人们正致力于免疫接种来控制蜱及蜱传疾病,但蜱对宿主产生了一系列的免疫调节作用,为抗蜱免疫接种的实施增加了难度。文章就蜱对宿主的免疫调节方式,减弱淋巴细胞增殖反应,扰乱细胞因子的产生和分泌;阻碍宿主B细胞的增殖与抗体产生;抑制补体旁路的激活;破坏NK细胞的杀伤功能;抑制巨噬细胞引起的炎性反应等方面进行了概述。对目前已发现的一些免疫调节蛋白如IgG结合蛋白(IGBPs)、唾液腺抗补体蛋白(Isac)、IL 2 结合蛋白(IL 2BP)、免疫抑制剂(Iris)等研究状况进行了综述,为抗原的进一步筛选和优化提供参考。     

警犬蜱综合防治技术的研究

蜱是节肢动物,它是一种吸血外寄生虫,在医学、寄生虫学、昆虫学上具有重要的地位。全世界已发现约800余种,计硬蜱科约700多种,软蜱科约150种,纳蜱科1种。我国已发现的硬蜱科约100多种,软蜱科10种。蜱的繁殖力极强,一只雌蜱最多能产25388只。蜱寄生宿主种类较为复杂,包括冷血动物、鸟类、哺乳动物,甚至于人。蜱的危害体现在两方面,直接危害:蜱通过叮咬宿主体表,吸血,刺激叮咬部发炎、水肿,分泌毒素,使宿主呈运动功能麻痹性瘫痪,引起死亡。曾有报道人因蜱寄生吸血而致麻痹死亡。更重要是它是许多人和动物疾病的病原体传播媒介和保虫宿主,它可…     

硬蜱的实验室饲养繁殖技术和常见问题

硬蜱既是常见的吸血外寄生虫,又是人和动物许多重要痰病的传播媒介,硬蜱研究材料的获取,依赖于实验室饲养繁殖。文章对硬蜱在试验条件下的动物饲血、孵育、蜕皮和繁殖技术做了具体介绍,并对主要影响因素,如宿主的适应能力,温度、湿度等方面进行了评述,对饲养中常见的问题进行了讨论。     

非洲猪瘟疫苗研究进展

非洲猪瘟(ASF)是由非洲猪瘟病毒引起的、以软蜱为传播媒介的猪的急性、热性、高度接触性传染病。该病毒主要在网状内皮细胞和单核巨噬细胞中复制,造成细胞凋亡,严重影响宿主的免疫系统。该病虽最早见报于1921年,但由于病毒基因组大,基因型多且非常容易变异等客观原因,造成至今无有效的疫苗面世。国外ASF疫苗研发一直在开拓前行,而国内大多数文献只进行了简单的描述,没有全面展示ASF疫苗的研究进展,为此作者就ASF疫苗的相关研究进展进行综述,以期为我国ASF的疫苗研究提供参考。     

蜱的生物防治研究进展

蜱是放牧家畜体表常见的一类外寄生虫,并可作为许多疾病的传播媒介,给人类健康和动物生产带来极大的威胁。在自然界中,多种病毒、细菌、真菌和线虫可寄生于蜱体并对其产生致病性,某些寄生蜂和禽类等可充当蜱的捕食者或天敌,它们在蜱的防控中均担当着重要角色。文章将以蜱的病原和天敌为重点,对蜱的生物防治研究进展进行介绍。     

蜱类唾液的采集方法

<正>蜱是一类以吸血为生的体外寄生虫,对人和动物具有直接和间接双重危害,但迄今为止人们尚无安全、高效、环保的防蜱灭蜱措施。以Bm86抗原为基础的抗蜱疫苗的成功研制和商品化激发了蜱学工作者鉴定功能蛋白、筛选候选抗原的热情,且成效明显。蜱唾液中含有大量的功能蛋白,对蜱吸血活动至关重要,其中一些蛋白具有疫苗开发价值,是分离、鉴定蜱唾液功能蛋白的重要来源。由于蜱个体较小,采集比较困难,制约了很多科研人员的研究进程。近两年,笔者在实践     

非洲猪瘟病毒及其免疫调控分子机制

非洲猪瘟(ASF)是由非洲猪瘟病毒(ASFV)引起的一种以高热和出血为特征的急性传染病，世界动物卫生组织(WOAH)将其列为法定报告动物疾病，我国也将其列为一类动物疫病。由于ASFV的环境稳定性以及能借助中间宿主软蜱和不易感宿主野猪进行传播的能力，使其防控具有一定难度。另外，由于缺乏对ASFV庞大的基因组和对应的编码蛋白的了解，其免疫学和疫苗学相关研究也具有一定的挑战。在缺乏具有稳定保护效力的安全疫苗情况下，ASF防控仍以扑杀和生物安全措施为主，这使得在应对ASF的过程中消耗了大量的人力、物力和财力。虽然我国2018年首次暴发ASF疫情后在较短的时间内即控制住了疫情进一步传播，但目前ASF依旧威胁着包括我国在内的全世界养猪行业的发展。本文对ASF的疾病特征、病原学特征和疫苗研发，以及ASFV所引起的天然免疫反应、适应性免疫反应等方面的研究进展进行概述，以期为ASFV的免疫学相关研究和ASF的疫苗研发提供一定的启示。     

Communal cattle farmer’s knowledge,attitudes and practices on ticks (Acari: Ixodidae), tick control and acaricide resistance

The aim of this study was to reveal communal farmer’s knowledge, attitudes and practice on ticks and tick-borne diseases affecting cattle, tick control methods used and their knowledge on acaricide resistance. A total of 160 structured questionnaires are prepared and randomly administered to cattle farmers in Sinqu and Elundini communities in the Eastern Cape Province, South Africa. Associations between the area, gender, age, employment, source of income, level of education and farming experience were statistically tested using Chi-square test. Gall sickness (63%) was the most prevailing tick-borne disease in cattle during the summer season (61%). About 59% of the farmers had no knowledge of the effect of tick-borne diseases on cattle production, and 78% of respondents reported that ticks are the major challenge to cattle farming. Pour-on (61%) was the most commonly used acaricidal treatment system with every fortnight (40%) treatment frequency during the summer season and (31%) during the winter season. Pyrethroids (73%) were the most used acaricide compounds to control ticks, and about 65% of respondents perceived to have no knowledge of the use of ethnoveterinary medicines used to control ticks. Inefficacy of acaricide (44%) and undipped animals (42%) were regarded as the major contributing factors to the increased tick population and acaricide resistance. About 85% of respondents perceived that they do not practice acaricide rotation and 88% of the respondents had no knowledge of the acaricide resistance. Within the context of this study, ticks and tick-associated diseases are perceived by these farmers as the most important disease problem their cattle face. Thus, knowledge regarding the epidemiology of ticks and tick-borne diseases is key to control strategies, and farmer training should be encouraged to achieve better control of ticks and the diseases they transmit.

     

Ecological preferences of exophilic and endophilic ticks (Acari: Ixodidae) parasitizing wild carnivores in the Iberian Peninsula

Ticks parasitizing wild carnivores and the tick-borne pathogens (TBPs) that they transmit may affect domestic carnivores and humans. Thus, investigating the role of wild carnivores as tick hosts is of relevance for understanding the life cycle of ticks in natural foci and the epidemiology of TBPs shared with domestic animals and humans. Therefore, the main objective of this study was to determine the ixodid tick fauna of wild carnivores in Peninsular Spain and the environmental factors driving the risk of wild carnivores to be parasitized by ixodid ticks. We hypothesized that the adaptation of tick species to differing climatic conditions may be reflected in a similar parasitization risk of wild carnivores by ticks between bioclimatic regions in our study area. To test this, we surveyed ixodid ticks in wild carnivores in oceanic, continental-Mediterranean, and thermo-Mediterranean bioclimatic regions of Peninsular Spain. We analyzed the influence of environmental factors on the risk of wild carnivores to be parasitized by ticks by performing logistic regression models. Models were separately performed for exophilic and endophilic ticks under the expected differing influence of environmental conditions on their life cycle. We found differences in the composition of the tick community parasitizing wild carnivores from different bioclimatic regions. Modelling results partially confirmed our null hypothesis because bioclimatic region was not a relevant factor influencing the risk of wild carnivores to be parasitized by exophilic ticks. Bioclimatic region was however a factor driving the risk of wild carnivores to be parasitized by endophilic ticks. Spanish wild carnivores are hosts to a relevant number of tick species, some of them being potential vectors of pathogens causing serious animal and human diseases. Information provided herein can be of help to understand tick ecology in Spanish wildlife, the epidemiology of tick-borne diseases, and to prevent the risks of TBPs for wildlife, domestic animals, and humans.     

The effect of the bont tick (Amblyomma hebraeum) on the weight gain of Africander steers

The effects of the bont tick Amblyomma hebraeum on the productivity of cattle need to be quantified in order to design economically optimal control programs. Liveweight gains (LWGs) of three groups of Africander steers, maintained in the same pasture and exposed to zero, medium or high numbers of larvae, nymphs and adults of the tick, were measured. Larvae and nymphs had no significant effect on LWG but adults had a large, statistically significant effect (P less than 0.05). The tick-free group had an average LWG of 20 kg more than the heavily infested group after 3.5 months. No mortality was recorded from ticks or tick-borne diseases during the experiment. There was no relationship between the number of engorging adult female ticks counted and loss of LWG of individual animals. The latter suggests that exposure to ticks as well as engorgement by female ticks causes losses. The loss per adult female that completed engorgement was estimated, by relating the LWGs of individual animals to their tick infestations, to be 4 +/- 2 g per adult female tick. An alternative estimate, made by comparing the average LWG and tick infestations of each treatment group, was equal to 10 +/- 4 g. This latter estimate includes the effect of challenge (and rejection) as well as tick feeding and so was accepted as giving the best estimate. Screw-worm fly (Chrysomya bezziana) struck an average of 7.5% of the cattle infested with ticks in any week but the effects on the productivity of the cattle were minimized by immediate treatment. There was a significant, positive correlation between the incidence of screw-worm fly strike and the numbers of adult ticks counted on the experimental animals. The results provide data for calculating losses caused by A. hebraeum in different parts of its geographical range.     

蜱的功能分子研究及其应用前景

蜱既是常见的吸血外寄生虫 ,又是人和动物许多重要疾病的媒介。为了持续地吸血 ,蜱唾液腺可分泌大量生物活性分子 ,并在抗凝血、抗炎症、免疫抑制等方面发挥重要作用。现已分离鉴定出的蜱抗凝血多肽 (TAP)等新型抗凝血和其他多种具有免疫调节的功能分子。此外 ,抗蜱基因工程疫苗候选抗原分子、酶及酶的抑制剂分子、抗药性相关分子、抗菌多肽和毒素等也在被深入研究。这些功能分子不仅在蜱及蜱传染病防制中显示着重要作用 ,同时也在医药生物制剂开发研制上表现出潜在的重要价值 ,显示着它们多方面广阔的应用前景     

Impact of climate change in the epidemiology of vector-borne diseases in domestic carnivores

Vector-borne diseases are medically important in humans and animals but were long considered tropical and known to first affect production animals. This is no longer true and we can see today that they are common in domestic animals and that they are also present in temperate countries, especially in Europe. In recent years, an increase in the diagnosis of vector borne diseases among humans and animals has been observed, which may partly due to the development of diagnostic tools. Their study requires exchanges and collaborations between the many actors involved, especially since the epidemiology seems to be constantly evolving. The veterinary practitioner is the first one to notice the emergence of cases and to implement prevention measures. He also acts as a sentinel to alert epidemiologists. Many factors can explain the epidemiological changes, i.e. all human factors, such as the increase in commercial transportation, but also owners traveling with their pet during the holidays, the development of “outdoor” activities, the increase of individual housings with gardens; to these human factors must be added the ignorance of the risks, linked to animals in general and to wildlife in particular; then the environmental changes: forest fragmentation, establishment of parks; the increase of wild mammal populations (deer, carnivores, rodents, etc.); finally, climate changes. Climate change is a reality which may explain the increase of density of arthropod vectors, but also of their hosts, changes in periods of activity and variations in geographical distribution. The authors show the proof of the climate modifications and then explain how it has an impact in Europe on ticks, mosquitoes, sandflies and even fleas. They conclude on the practical consequences for veterinary practitioners, especially with the diagnosis of parasitic diseases or diseases in areas where they usually do not occur. However, not any epidemiological modification should be linked to climate change, since many other factors are involved and often even overriding.     

Molecular identification of tick-borne bacteria in wild animals and their ticks in Central Anatolia,Turkey

Wild animals fulfill an important mission in the ecology of tick-borne diseases as both suitable hosts to tick vectors and reservoirs of the pathogens. However, current data regarding the role of wild animals in the ecology of tick-borne pathogens is insufficient and more investigations are required. In this study, we investigated tick-borne bacterial pathogens in wild boar, hare, and fox and their ticks in Turkey. A total of 102 tick pools comprised of 445 ticks and blood samples were analyzed for the presence of bacterial DNA by PCRs targeted rickettsial gltA and ompA genes, 5S-23S rDNA gene for Borrelia spp., and msp4 gene for Anaplasma spp. As a result of PCR and sequence analyses, three pathogenic spotted fever group (SFG) rickettsiae, two SFG rickettsiae with unknown pathogenicity and one pathogenic Borrelia burgdorferi sensu lato were detected in samples obtained from wild animals. Rickettsia slovaca was detected in ticks (13.7% of tick pools) collected from wild boars and blood of a wild boar. In addition, the presences of R. hoogstraalii (19.6% of tick pools), R. aeschlimannii (5.8% of tick pools), R. sibirica subsp. mongolitimonae (1.9% of tick pools) and Candidatus R. goldwasserii (0.9% of tick pools) were detected in ticks collected from wild animals. Furthermore, B. burgdorferi sensu stricto was detected in a tick pool collected from a wild boar. This is the first report on the presence of Candidatus R. goldwasserii in Turkey. Consequently, this study shows that pathogenic Rickettsia and Borrelia species are circulating in Turkish wildlife and these pathogens can pose a threat to human health. Also, it has been determined that the investigated wild animals play a role as maintenance host for vector ticks; therefore, these animals must also be considered in the ecology of the mentioned pathogens.     

Ixodid and argasid ticks. Keys to their identification

Ticks of the Ixodidae family are important ectoparasites of humans and animals. Of the 80 or so species found in the United States, about 20 are of veterinary importance. Ticks are second only to mosquitoes as carriers of human pathogens. The ixodid (or hard) ticks are the most common and are represented by the genera Ixodes, Haemaphysalis, Boophilus, Rhipicephalus, Amblyomma, and Dermacentor. Accurate identification of the species of ixodid ticks within an area is a prerequisite to control and eradication. Therefore, veterinarians should have a working knowledge of the biology and identity of the more common mammalian-parasitizing ticks in the United States. In the United States, the argasid (or soft) ticks are less common than the ixodid (or hard) ticks. Argasids are represented by the genera Argas, Ornithodoros, and Otobius. Although the overall anatomy of the various species of argasids is similar, their functional approaches to feeding, reproduction, host finding and preference, tick-host behavior, tick relationship to their environment, and disease association vary among species. Accurate identification of the species of argasid ticks within an area is useful in their control.     

Natural transmission of heartwater

Heartwater has been transmitted experimentally by 12 Amblyomma species. Their importance depends on the extent of their distribution, adaptation to domestic stock and their efficacy as vectors. Except for one report of transovarial transmission, transmission is transstadial. Ticks may obtain the infection while feeding on reacting animals, subclinically infected hosts or perhaps on immune animals after reinfection. There is a marked increase in the infectivity of infected ticks during feeding but this decreases before and during moulting. The demonstration of Cowdria ruminantium in salivary glands of ticks suggests that transmission takes place via the saliva and that regurgitation from the gut may not be as important as previously thought. Transmission takes place on the 2nd day from the time infected nymphae were placed on the animals and on the 4th-day in the case of adult ticks.