The persistence of hepatitis B antigen in the bloodmeal of the potential medicinal leech, Asiaticobdella buntonensis

The persistence of the hepatitis B virus surface antigen (HBsAg) was used as an index of the survival time of this virus within the gastro-intestinal tract of the potential southern African medicinal leech, Asiaticobdella buntonensis. HBsAg was tested for in blood/faecal material at five intervals over 15 weeks. Samples from both the midgut and the rectum remained positive for the entire test period, although with decreasing strength. The results are compared with reports on other arthropods which indicate increasing antigen persistence with increasing body size. The findings implicate medicinal leeches as mechanical vectors of HBV and possibly of other medically important viruses, and argue against using leeches of suspect or unknown origin in the alleviation of venous congestion in failing microsurgical procedures

Avoidance responses of some indigenous and exotic freshwater pulmonate snails to leech predation in South Africa

The avoidance behaviour elicited from four species of freshwater pulmonate snails, Physa acuta and Aplexa marmorata (Physidae), Bulinus tropicus (Planorbidae) and Lymnaea natalensis(Lymnaeidae), following contact with a molluscivorous leech Hebbdella conifera (Glossiphoniidae), was examined experimentally. Although H. conifera showed no species preference for any of those species it attacked, the physids, both exotics, were killed less often than would be expected by chance. The indigenous species, B. tropicus and L natalensis, were more susceptible to leech attack than the introduced species. Size-preference trials using P. acuta showed decreased susceptibility to leech attack with an increase in snail size. These results are interpreted with reference to the mode of leech attack and to differences in snail morphology

Gametogenesis in the leech Asiaticobdella buntonensis (Meyer, 1951) (Hirudinidae)

The gametogenic cycle of the leech, Asiaticobdella buntonensisfrom two localities was investigated and found to be simultaneously hermaphroditic. Spermatogenesis reached a state of maturation before oogenesis in a cycle of summer reproductive maturation and winter quiescence comparable to related Hirudinidae. Leeches collected from the more northerly, warmer water bodies on the Makhatini Flats (32°08'E /27°27'S) were similar, although there is some evidence that their gametes matured earlier and remained in a mature condition longer than those collected from the more temperate collection site at Happy Valley Nature Reserve, Durban (31°00'E /30°00'S). An understanding of the gametogenic cycle of this potential medicinal leech under natural conditions, provides an index against which the effects of manipulating laboratory conditions on mass rearing can be inferred

A new record of Craspedacusta sowerbii (Cnidaria: Limnomedusae) from southern Africa

The northern hemisphere Craspedacusta sowerbii has been recorded recently from temperate regions of South Africa. Its introduction to southern Africa is thought to have occurred in the 1940s, when a number of exotic species were introduced, associated with man's interference in river catchments. A new record from Theewaterskloof Dam, Cape Province, suggests that its spread is being facilitated by inter-basin translocation of the polyp stage. Histological analysis of the gonads of medusae from Theewaterskloof impoundment showed that they were all females, supporting the hypothesis that only one sex of medusa is budded from any one polyp colony

Book Reviews

Book Review 1Book Title: Waders of southern AfricaBook Author: Phil Hockey (Illustrated by Claire Douie)Struik Winchester. Cape Town. 1995. 288 pp.Book Review 2Book Title: Apple Snails in the AquariumBook Author: Gloria Perera & J.G.WallsPublished by T.F.H. Publications, Neptune, New Jersey 07753. (1996).Book Review 3Book Title: The African Leopard: Ecology and Behavior of a Solitary FelidBook Author: Theodore N. BaileyColumbia Universily Press, New York. 1993. xviii + 429pp. ISBN 0-231-07872-2 (cloth)

Book Reviews

Book Review 1Book Title: Physiological Function in Special EnvironmentsBook Author: Edited by Charles V. Paganelli & Leon E. FarhiSatellite Symposium of the American Physiological Society Fall Meeting (1985). Springer:Verlag New York Inc.Book Review 2Book Title: Parasitic DiseasesBook Author: M. Katz, D.D. Despommier & R. Gwadz Second edition, Springer-Veriag, 1988. 301 pages.Book Review 3Book Title: The Unheeded Cry - Animal Consciousness, Animal Pain, and ScienceBook Author: Bernard E. Rollin Published by the OUP. 308 pages

Sources, mobility and bioaccessibility of potentially harmful elements in UK soils

Potentially harmful elements (PHE) occur both naturally from geogenic sources and from anthropogenic derived pollution. Anthropogenic sources can be further categorised into those derived from point sources. A point source is a single identifiable source which is confined to a very small area such as that arising from disposal of waste material or from an industrial plant. Diffuse pollution arises where substances are widely used and dispersed over an area as a result of land use activities, often associated with urban development. Examples of diffuse pollution include atmospheric deposition of contaminants arising from industry, domestic coal fires and traffic exhaust, and disposal of domestic coal ash. The total concentration and the chemical form and hence the mobility of the PHE in a soil is highly dependent on the source

Book Reviews

Book Review 1Book Title: Sociobiology and Conflict. Evolutionary perspectives on competition, cooperation, violence and warfareBook Authors: Edited by J. van der Dennen & V. Falger Published by Chapman and Hall, LondonBook Review 2Book Title: Namib EcologyBook Author: Edited by M.K. SeelyTransvaal Museum Monograph No.7, 1990.Book Review 3Book Title: Bird MigrationBook Author: T. Alerstam Cambridge University Press, 1990. 420 pages ISBN 0521 328 659.Book Review 4Book Title: Parasitism and Host BehaviourBook Authors: Edited by C.J. Barnard & J.M. BehnkePublished by Taylor & Francis Ltd, London.Book Review 5Book Title: The Mammals of the Southern African SubregionBook Authors: J.D. Skinner & the late R.H.N. Smithers Published by the University of Pretoria, 1990

Community perception of mosquitoes, malaria and its control in Binga and Gokwe Districts, Zimbabwe

A journal article on the importance of community participation in health care initiatives in rural Zimbabwe.The success of community participation in primary health care depends on the peoples’ knowledge, attitudes and practices in relation to the diseases that affect them. Given the changing health care delivery system in Zimbabwe, greater self reliance on the part of affected communities is expected to play a greater role in future. As far as malaria prevention and control is concerned, this is designed to operate in largely marginalized communities which have previously relied on state run control operations. Annual indoor house spraying using residual insecticide remains the main method for malaria control in Zimbabwe but the trend is shifting towards integrated control encompassing the use of personal protection for prevention and environmental and biological means for source reduction of vector mosquitoes. The use of insecticide impregnated bed nets has gained popularity with the World Health Organization as a malaria control measure following successful trials in West and East Africa

The structure of the shell and polar plugs of the egg of the whipworm, Trichuris trichiura (Nematoda : Trichuridae) from the Samango monkey (Cercopithecus albogularis)

The structure of the shell of the egg of Trichuris trichiura was examined using light microscopy as well as scanning and transmission electron microscopy. The results confirmed its three-layered structure and provided evidence that the cores of the polar plugs, which could be seen to be extensions of the shell's middle layer, could be lost en bloc, either mechanically or chemically, and in this way probably provided an exit for the first stage larva at hatching.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201