Some helminth parasites of marine fishes of south Africa: family Opecoelidae (Digenea)

The following digeneans are described, recorded or figured from South African waters: Pseudopecoelus ablennesi sp. nov. from Ablennes hians; Coitocaecum capensis sp. nov. from Clinus superciliosus, C. cottoides, Gynutoclinus rotundifrons, Xenopoclinus kochi and X. leprosus; Dactylostomun griffithsi sp. nov. from Cheilodactylus fasciatus; Margolisia vidalensis gen. nov., sp. nov. from Trachinocephalus myops; Pachycreadium obovatum from Sparodon durbanensis, Diplodus cervinus and Cheilodactylus fasciatus; Allopodocotyle recifensis sp. nov. from Pterogymnus laniar; Helicometra fasciata in Arius feliceps, Chirodactylus brachydactylus, Clinus capensis, C. cottoides, C. superciliosus, Gynutoclinus rotundifrons, Pachymetopon blochii, Pomadasys olivaceus, Pomatomus saltator, Xenopoclinus kochi and X. leprosus; Helicometrina nimia from Rhonciscus anus. The other taxa discussed are the genera Pseudopecoelus, Coitocaecum (synonyms Ozakia, Pseudocoitocaecum, Paradactylostomum), Dactylostomum, Pachycreadium and Allopodocotyle. In discussion the following new combinations are made: Coitocaecum (formerly Pseudocoitocaecum) bombayensis (Ahmad, 1983); C. (formerly P.) thrissoclesis (Bilqees, 1972); Dactylostomum (formerly Ozakia) iniistii (Yamaguti, 1970); D. (formerly O.) pfluegeri (Yamaguti, 1970); D. (formerly Coitocaecum) xesuri (Yamaguti, 1940); Allopodocotyle (formerly Podocotyle (Pedunculotrema) israelense (Fischthal, 1980); Allopodocotyle (formerly Podocotyle) jaffensis (Fischthal, 1980).     

Selection for class IIMhc heterozygosity by parasites in subterranean mole rats

Mhc organization and polymorphism have previously been studied²⁶ in the four chromosomal species of theSpalax ehrenbergi superspecies in Israel, serologically, and at the DNA, RFLP and sequence levels of class I and class II genes. Here we demonstrate that the observed heterozygosity ofMhc class II genesP₁ with 11 alleles, andQ, with at least 14 alleles, is positively and significantly correlated with infectivities of ectoparasites (gamasid mites)¹⁷ and endoparasites (helminths)¹⁸.Mhc heterozygosity is highest in the most infected area, which is in the most humid-warm region of the superspecies range, or where two zoogeographic regions overlap. We conclude that the evolutionary forces responsible for theMhc class II two-gene polymorphisms include selection for increased heterozygosity as a defense strategy against ecto- and endoparasite infections.     

危害规模化养猪场的主要寄生虫及其防治措施

危害规模化养猪场的主要寄生虫有猪疥螨、猪线虫和猪血虱 .这些寄生虫感染造成的主要危害是降低饲料报酬和生长速度 ,并可能诱发其他疾病 .胃肠道线虫的最常用诊断方法是粪便检验 ,计算粪便中虫卵种类和数量 ;猪疥螨的诊断则需以临床症状为基础 ,检查皮肤的碎屑或进行血清学检查 .寄生虫病的防治措施主要有 :预防为主 ,加强饲养管理 ,选用适当的抗寄生虫药物 (如通灭 ) ,优化驱虫方案     

青海地区寄生虫标本采集途径

本文介绍了青海人体寄生虫学实验标本现状,针对寄生虫标本较为短缺的问题,采取多种途径解决矛盾.尤其是利用青海独有的寄生虫标本,与外省院校标本互换,达到了资源共享,优势互补的目的.同时积极利用现代电子技术,使教学工作信息化.     

Parasites of the Lessepsian invasive fish Lagocephalus sceleratus (Gmelin 1789) in the eastern Mediterranean Sea

Lagocephalus sceleratus, is a Lessepsian invasive fish species introduced into the Mediterranean Sea through the Suez Canal. This study investigated it as host of parasites. Out of 41 individuals caught from northern and southern locations of the eastern Aegean Sea, nine were found to host parasites. Gnathia sp. praniza larva, an ectoparasite, was associated with severe damage of the primary and secondary structures of the gills and it was found in one specimen (prevalence 2.4%). Regarding endoparasites, Anisakis type I third-stage larvae were found in two specimens (prevalence 4.9%). In addition, adult nematodes of Hysterothylacium aduncum were found in another six specimens (prevalence 14.6%). Lagocephalus sceleratus is a new host for some indigenous parasites, with low host specificity, in the Mediterranean Sea, providing an additional niche for the success and increase of local populations of these parasites and, to our knowledge, this is the first record of L. sceleratus parasites in this area. Whether these parasites can control the invasion success of L. sceleratus needs to be further investigated. However, the low mean intensity of infection found in this study does not support such control.     

进口鳕鱼的寄生虫学调查

鳕鱼是一种冷水性大洋海鱼，产量和营养价值均高，但寄生虫种类众多。本文对进口鳕鱼进行了寄生虫学调查，以探讨如何合理利用和保证人类健康。     

Endoparasites of the European ground squirrel (Spermophilus citellus) (Rodentia: Sciuridae) in central Macedonia,Greece

The European ground squirrel (Spermophilus citellus) is a small rodent categorized as vulnerable (IUCN). To investigate the parasitic fauna of this species in Greece, faecal samples from 125 animals belonging to six different populations were examined by standard parasitological methods. Parasites were found in 118 of the animals (94.4%). Oocysts of the coccidia Eimeria callospermophili were found in 92 animals (73.6%), Eimeria citelli in 76 (60.8%), Eimeria cynomysis in 41 (32.8%), Eimeria spp. (17.6%), Cryptosporidium spp. in 29 (23.2%), cysts of Entamoeba spp. in 32 animals (25.6%) and eggs of the trematode Brachylaima spp. in seven animals (5.6%). This is the first report of Entamoeba spp., Cryptosporidium spp. and Brachylaima spp. in S. citellus. The possible impact of these findings on the health status of S. citellus and the possible significance to domestic animals or public health is discussed.     

Preventing a population decline of red grouse (Lagopus lagopus scoticus) by manipulating density

Summary This experiment tested whether a cyclic-type population decline can be prevented by removing territorial cock red grouse to keep breeding density below peak levels. The manipulated population did not decline, despite big decreases in food and breeding success, and more parasitic threadworms per bird than on the control.     

The adaptive significance of sexuality

Summary A theory of sexuality and polymorphism is proposed in which diversity at the molecular level is the adaptive response of multicellular organisms to the challenge of microparasites that have smaller genomes, shorter generation times and which can evolve more quickly than their hosts. The theory has implications for genetically homogenized crops and other cultivated plants as well as for immunology. A different function of sexuality is proposed for microorganisms that reproduce both asexually and sexually. Several possible experimental tests are discussed. Mathematical modelling techniques are outlined qualitatively and compared with game-theoretical methods which may be interpreted as simplifications of population dynamic and genetic equilibria. Some results about equilibria, stability and extinction in the population dynamics of polymorphic host-parasite populations are referenced.     

湖北省人体寄生虫种类及分布的初步研究

按分层整群随机抽样法,调查了湖北省３９个县（市、区）,５３２８４人,湖北省人体寄生虫平均感染率５２．０４％,确定的虫种６５种,分布于全省各县（市、区）的虫种１７种,驻见于少数地区极少数人群的少（罕）见虫种１３种,棘口科吸虫,横川后殖吸虫,猫后睾吸虫,异形异形吸虫,小杆线虫铁线虫、美丽筒线虫和缩小膜壳绦虫等系省内首次报道,寄生虫感染和分布与地理条件,气候,社会经济基础、卫生条件、人群职业,年龄,生活