Biomaterial Database

Distribution and habitats of the snail Lymnaea truncatula, intermediate host of the liver fluke Fasciola hepatica, in South Africa. 2003

K N de Kock, and C T Wolmarans, and M Bornman

School of Environmental Sciences and Development, Zoology, Potchefstroom University for CHE, Private Bag X6001, Potchefstroom 2520, South Africa. drkkndk@puknet.puk.ac.za

This paper focuses on the geographical distribution and habitats of Lymnaea truncatula, the intermediate, snail host of the liver fluke, Fasciola hepatica, as reflected by the 723 samples in the database of the National Freshwater Snail Collection, Potchefstroom, South Africa. The 221 different loci (1/16-degree squares) on record reflect an extensive but discontinuous distribution, except in Lesotho and in parts of the Mpumalanga, Gauteng and North West provinces of South Africa. Although recorded from 12 different types of waterbody, it was mostly (42.0%) recovered from swamps. Most samples (45.8%) were collected in habitats with slow-flowing water. A muddy substratum was recorded for 62.5% of the samples. Most samples (86.3%) were collected in habitats with a mean annual air temperature of 10-20 degrees C, and more than 69% came from localities with a mean annual rainfall of 600-900 mm. An integrated decision tree constructed from the data indicated that temperature and types of waterbody play a decisive role in determining the presence of L. truncatula in a given area. A temperature index calculated for all mollusc species ranked L. truncatula second in a total of 53 species according to its association with low temperatures. It remains to be established whether its distribution is indeed discontinuous, and whether its preference for a particular habitat, amphibious habits and ability to aestivate could have resulted in some populations having been overlooked during surveys.

UI	MeSH Term	Description	Entries
D008195	Lymnaea	A genus of dextrally coiled freshwater snails that includes some species of importance as intermediate hosts of parasitic flukes.	Lymnea,Lymnaeas,Lymneas
D008297	Male		Males
D011156	Population Density	Number of individuals in a population relative to space.	Overpopulation,Population Size,Underpopulation,Densities, Population,Density, Population,Population Densities,Population Sizes
D002980	Climate	The longterm manifestations of WEATHER. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Climates
D003710	Demography	Statistical interpretation and description of a population with reference to distribution, composition, or structure.	Demographer,Demographic,Demographic and Health Survey,Population Distribution,Accounting, Demographic,Analyses, Demographic,Analyses, Multiregional,Analysis, Period,Brass Technic,Brass Technique,Demographers,Demographic Accounting,Demographic Analysis,Demographic Factor,Demographic Factors,Demographic Impact,Demographic Impacts,Demographic Survey,Demographic Surveys,Demographic and Health Surveys,Demographics,Demography, Historical,Demography, Prehistoric,Factor, Demographic,Factors, Demographic,Family Reconstitution,Historical Demography,Impact, Demographic,Impacts, Demographic,Multiregional Analysis,Period Analysis,Population Spatial Distribution,Prehistoric Demography,Reverse Survival Method,Stable Population Method,Survey, Demographic,Surveys, Demographic,Analyses, Period,Analysis, Demographic,Analysis, Multiregional,Demographic Analyses,Demographies, Historical,Demographies, Prehistoric,Distribution, Population,Distribution, Population Spatial,Distributions, Population,Distributions, Population Spatial,Family Reconstitutions,Historical Demographies,Method, Reverse Survival,Method, Stable Population,Methods, Reverse Survival,Methods, Stable Population,Multiregional Analyses,Period Analyses,Population Distributions,Population Methods, Stable,Population Spatial Distributions,Prehistoric Demographies,Reconstitution, Family,Reconstitutions, Family,Reverse Survival Methods,Spatial Distribution, Population,Spatial Distributions, Population,Stable Population Methods,Technic, Brass,Technique, Brass
D004199	Disease Vectors	Invertebrates or non-human vertebrates which transmit infective organisms from one host to another.	Infectious Disease Vectors,Disease Vector,Disease Vector, Infectious,Disease Vectors, Infectious,Infectious Disease Vector,Vector, Disease,Vector, Infectious Disease,Vectors, Disease,Vectors, Infectious Disease
D004777	Environment	The external elements and conditions which surround, influence, and affect the life and development of an organism or population.	Environmental Impact,Environmental Impacts,Impact, Environmental,Impacts, Environmental,Environments
D005210	Fasciola hepatica	A species of helminth commonly called the sheep liver fluke. It occurs in the biliary passages, liver, and gallbladder during various stages of development. Snails and aquatic vegetation are the intermediate hosts. Occasionally seen in man, it is most common in sheep and cattle.	Liver Fluke,Fasciola hepaticas,Fluke, Liver,Flukes, Liver,Liver Flukes,hepatica, Fasciola
D005211	Fascioliasis	Liver disease caused by infections with parasitic flukes of the genus FASCIOLA, such as FASCIOLA HEPATICA.	Fasciola Infection,Fasciola Infections,Fascioliases,Infection, Fasciola,Infections, Fasciola
D005260	Female		Females