Observations on the attachment of a piscine gill parasitic ergasilid (Crustacea: Copepoda)

The attachment of the piscine gill parasite, Ergasilus mirabilis Oldewage & van As, 1987 is described by means of scanning electron microscopy and light microscopy. A variety of sensory structures occur on and around the host contact surface of the parasite and proliferation of gill tissue occurs at the site of attachment. It would appear that this proliferation of host tissue results from the feeding behaviour of the parasite rather than the actual attachment thereof.     

A New Species of Mugilicola Parasitic on South African Elvers (Copepoda,Therodamasidae)

A new species of parasitic copepod belonging to the genus Mugilicola Tripathi, I960 (CYCLOPOIDA: THERODAMASIDAE) is described. The copepods were embedded in the buccal cavity of elvers of Anguilla mossambica caught in South African rivers.     

Occurrence and pathology of Sinergasilus lieni (Copepoda: Ergasilidae), a parasite of the silver carp and bighead, in Hungarian ponds

Sinergasilus lieni Yin, 1949, a well-known and pathogenic parasitic copepod in China and Russia, has been detected in Hungarian carp farms for the first time. The parasite infected the third-year generation of silver carp (Hypophthalmichthys molitrix) and bighead (Aristichthys nobilis). The gills of the infected fish specimens showed severe pathological changes. At the attachment sites of female copepods clubbing and fusing of the gill filaments were observed and in some parts of the pale or whitish hemibranchia deep indentations were recorded in places where the tips of the damaged filaments had broken off. Silver carp and bighead were infected at a similar rate, having 8 to 27 copepods attached to the end of the clubbed filaments or the proliferated epithelium of 2 to 10 fused filaments. In histological sections the head part of the parasite was found in a deep cavity of the proliferated epithelium, piercing its antennae deep into the tissues. Only the end of the filaments showed changes. In this part the proliferated epithelium was infiltrated by eosinophilic granular cells. In the central and basal parts of the hemibranchia the original structure of the filaments was preserved with intact secondary lamellae.     

Redescription and molecular characterisation of the fish parasitic isopod Norileca indica (Milne Edwards, 1840) (Crustacea: Isopoda: Cymothoidae) with a key to the genus

Norileca indica (Milne Edwards, 1840) is fully redescribed based on ovigerous females collected from Maputo Bay, Mozambique, from the branchial cavity of the fish host Selar crumenophthalmus Bloch, 1793. An identification key to the species of Norileca Bruce, 1990 is given. Furthermore, a fragment of the mitochondrial cytochrome oxidase I (COI) gene from N. indica was sequenced for the first time. This is the first molecular characterisation of a species of Norileca.     

Polystomatidae (Monogenea) of southern African Anura: Polystoma channingi n.sp. parasitic in two closely related Cacosternum species

Polystoma channingi is described as a new species of polystomatid flatworm (Monogenea) parasitic in the urinary bladder of Cacosternum nanum in the Eastern Cape Province, South Africa. In a locality where C. nanum and C. boettgeri occur sympatrically the parasite has been found in both species. This finding of a Polystoma sp. in two closely related host species questions the strict host-specificity generally ascribed to the genus, but supports the hypothesis that host-specificity is determined by the oncomiracidium's ability to recognize the tadpole as a suitable host. This is the first polystome to be described from the genus Cacosternum and the ninth species of Polystoma from South Africa. The species is distinguished by its huge haptor and suckers relative to the body size. The haptor length/body length ratio of 0.38 is by far the largest for the known southern African polystomes. The prevalence of infection with P. channingi n.sp. was 25% for C. nanum and 40% for C. boettgeri, while the mean intensity of infections in adult frogs was 1.5 for C. boettgeri and 1.0 for C. nanum.     

On the fine structure of female Caligus infestons Heller, 1865 (Copepoda: Siphonostomatoida)

Although much work has been done on the piscine parasitic genus Caligus Müller, 1785, morphological and especially anatomical work has been largely neglected, leading to confusion as to, for instance, the phylogenetic origin and identity of appendages. The present study provides scanning electron microscopical information on the fine structure of the female of Caligus infestans Heller, 1865. The study of the true ultrastructure and perhaps more important, the orientation of the appendages of these parasites, provide valuable information on the functional adaptations towards the utilization of the parasitic niche.     

Cytosystematics of the South African Aethomys (Rodentia: Muridae)

The G-and C-band chromosome patterns and the location of the nucleolus organizer regions (NORs) are presented for A. namaquensis (2n = 24), A. granti (2n = 32) and A. chrysophilus (2n = 44; 2n = 50). The presence of two distinct cytotypes in what is conventionally recognized as A. chrysophilus is indicative of the presence of two discrete species which, karyology apart, appear to be indistinguishable using existing identification keys. The chromosomal relationships of the South African species and the taxonomic implications of these data are discussed.     

A check-list of the nematode parasites of South African Serpentes (snakes) and Sauria (lizards)

Published records, in combination with own data have been brought together to provide data on parasite/host relationships of reptiles that occur in the Republic of South Africa. A total of 62 nematode species belonging to 23 genera and 11 families are recorded from 20 snake and 21 lizard species. The genera Kalicephalus, Spauligodon, Ophidascaris and Abbreviata are especially well represented with between five and eight species per genus. The most nematode species were recorded from the flap-neck chameleon, Chamaeleo dilepis (eight), the puff-adder, Bitis arietans (eight) and the water monitor, Varanus niloticus (seven). All synonyms of parasites and hosts are given.     

真殖线虫属一新种记述(线虫纲:尖尾科)

作者于六十年代曾在西藏高寒山区捕获田鼠(Microtus sp.)计27只,经剖检于7只田鹿的盲肠中,共检获线虫标本28条,按常规处理后,以5％福尔马林液固定保存,现经形态学分析研究,发现4只田鼠中的8条线虫标本,系隶属线虫纲(Nematoda)、尖尾科(Oxyuridae)、真殖属(Eugenuris)中的一个新种,定名为西藏真殖线虫新种(Eugenuris xizangensis sp.nov.)。本新种在同属中主要区别要点在于:1.口腔分层明显,似2个花钵套接,口内腔呈梯形;2.头端侧翼膜于食道前半部的体表形成一颈泡;3.体前1/5范围之体表有数圈角质环纹;4.泄殖孔周围共为5对乳突,呈前后重叠,左右对称分别排列于孔前3对及孔后2对。现描记于后,全文计量单位为mm.(图1～7)。     

Eugenol for anesthesia of African clawed frogs (Xenopus laevis)

OBJECTIVE: To determine the level of anesthesia attained in Xenopus laevis frogs with eugenol at different doses and by different routes of administration. STUDY DESIGN: Prospective experimental trial. ANIMALS: Sixty X. laevis nonbreeding female frogs weighing between 90 and 140 g. METHODS: Three different routes of administration were tested - subcutaneous injections into the dorsal lymph sacs, topical administration using a gauze patch, and immersion in a bath containing eugenol. Following the determination of the best route of administration, the acetic acid test, the withdrawal reflex, righting reflex, heart rate, and respiratory frequency were used to evaluate central nervous system depression following eugenol bath administration. In an additional group, the response to a surgical incision of the abdominal wall was evaluated. The pharmacokinetics of eugenol were determined following bath immersion administration, and pharmacokinetic parameters were calculated following blood concentration determination by tandem liquid chromatography/mass spectrometry analyses. RESULTS: It was not possible to induce anethesia with subcutaneous and patch administration, independent of the eugenol dose administered. The immersion bath was the only efficacious route for anesthesia inducing surgical anesthesia for at least 30 minutes with postoperative analgesia. Histopathology of selected tissues (heart, lung, liver, kidneys, eyes) showed no evidence of lesions 24 hours following bath immersion. The elimination half-life (T(1/2)) was 4 hours. CONCLUSIONS: When administered as a single-bath immersion (dose 350 mg L(-1)) for 15 minutes, eugenol may serve as an effective anesthetic in X. laevis frogs for short surgical procedures.     

Patterns in the Distribution of Southern African Terrestrial Tortoises (Cryptodira: Testudinidae)

Distribution maps for the ten southern African species of land tortoise have been prepared using published sources and recent museum records. Three hundred and thirty-six new records have been added to these maps by a recent Cape Province tortoise survey, and a further 65 of the older records have been re-confirmed. A relatively clear picture of the range of each species is now available, although the records in South West Africa are not yet adequate enough to resolve the problems posed by the vague localities published at the beginning of the century. The Cape Province of South Africa clearly stands out as the world's richest area in terrestrial testudinids.     

Zoogeographical Patterns in the Distribution of East African Treefrogs (Anura: Ranidae)

The savanna fauna of treefrogs in East Africa includes five distributional patterns: a widely distributed element, an element in the savanna north of the central forest from Cameroun to northern East Africa, an element south of the central forest, an East African lowland fauna, and an element in the dry savanna of Kenya and northern Tanzania.

The forest fauna includes two elements: a western element connected with the Congo Forest block and an eastern element with a distribution similar to the East African lowland savanna fauna.     

A simulation model for genetic resistance to acaricides in the African brown ear tick,Rhipicephalus appendiculatus (Acarina: Ixodidae)

Network representations and computer modelling techniques were used to develop a framework in which to investigate the relationship between tick resistance to acaricides and genetic fitness. The computer model simulated the day-to-day occurrences experienced by ticks and allowed constants relating to the efficacy of acaricide dipping, and survival and development of the tick, in different stages, to be varied. Results are presented on the mean number of years taken for resistance to appear in a population of Rhipicephalus appendiculatus, maintained under climatic conditions similar to those experienced by ticks in the highlands of Kenya. The computer model which was employed also made it possible to study chemical resistance in other parasite systems, by changing constants regarding the species and the nature of the chemical control.     

A combination of different polymerase chain reaction (PCR) assays for the presumptive identification of Yersinia pestis

A combination of four polymerase chain reaction (PCR) assays targeting the Yersinia pestis-specific plasmoidal genes of the fraction 1 capsular antigen and plasminogen activator/coagulase, the gene of the V antigen of the Yersinia virulence plasmid, and the chromosomal 16S rRNA gene was evaluated for the identification of Y. pestis isolates. All four assays were subjected to the same sample preparation technique, reagents and cycling conditions. Eighteen Y. pestis, 66 Y. pseudotuberculosis, 40 Y. enterocolitica strains, the type strains of the other Yersinia species, and 20 other pathogenic bacterial strains were investigated. By using the proposed combination of PCR assays all Y. pestis strains were identified correctly. The applicability of this combination of PCR assays was demonstrated by the detection of Y. pestis DNA in spiked tissues from Rattus norwegicus and fleas (Xenopsylla cheopis and Ctenocephalides spp.). As little as 60 genome equivalents were detected. This system is applicable for monitoring Y. pestis and its vectors in enzootic natural foci and in the diagnosis of plague in humans and animals.     

Sexual dimorphism in the African legless skink subfamily Acontiinae (Reptilia: Scincidae)

The extent to which sexual dimorphism in snout–vent length, tail length and head shape (length, width and height) manifests itself in the legless fossorial skink subfamily Acontiinae was investigated in representatives of all four of its genera, Acontias, Microacontias, Acontophiops and Typhlosaurus. Where data were available fecundity selection and diet partitioning (ecological causation) were tested as possible proximate causes for dimorphisms found. The possibility of a relationship between head shape and microhabitat density was also investigated. The data showed that significant sexual dimorphism in snout–vent length and head shape was present in only a minority of taxa and that it was absent with respect to tail length. There are indications of a relationship between head shape and microhabitat density, and head shape seems to become increasingly more pointed as SVL increases. A serious impediment to placing the findings of this study into a firm evolutionary context is the general lack of information about the ecology, social organization and behaviour of the taxa.