scholarly journals Distribution and habitats of Bulinus tropicus, snail intermediate host of the conical fluke Calicophoron microbothrium, in South Africa

2002 ◽  
Vol 21 (4) ◽  
pp. 114-120
Author(s):  
K. N. De Kock ◽  
C. T. Wolmarans ◽  
M. Bornman ◽  
D. C. Maree

This paper focuses on the geographical distribution and the habitats of Bulinus tropicus, the snail intermediate host of the conical fluke, Calicophoron microbothrium. Bulinus tropicus is the freshwater snail species with the most extensive geographical distribution, as reflected by the collection sites of the 7 992 samples currently on record in the database of the National Freshwater Snail Collection (NFSC) of South Africa. The presence of this species was noted by collectors in a total of 14 different types of waterbodies, however, the largest number of samples was collected in dams and brooks and in habitats of which the water was described as standing, clear and fresh. The effect size was calculated for each variable separately to determine its importance in governing the distribution of this species. The data in the database were further processed and adapted to construct an integrated decision tree. This is a statistical model allowing the selection of those variables which can maximally discriminate between the frequency of occurrence of a given species and all other species in the database under specific conditions. The success of B. tropicus, as reflected by its extensive geographical distribution, can most probably be ascribed to the circumstance that population dynamic studies by various authors have shown, without any doubt, that it is highly r-selected and that it additionally has the ability to survive conditions of drought for elatively long periods. It does however, appear as if its limited tolerance to water with a relatively low conductivity could possibly be a limiting factor for its colonisation of specific areas in South Africa. As intermediate host of C. microbothrium which causes paramphistomosis in domestic stock and sometimes can lead to great losses, the wide distribution of B. tropicus has economic implications, especially for residents of informal, rural settlements whose livestock traditionally forms an integral part of their daily existence.

2001 ◽  
Vol 20 (2) ◽  
pp. 56-71
Author(s):  
Editorial Office

This paper focuses on the geographical distribution and the habitats of Lymnaea natalensis, the snail intermediate host of the liver fluke, Fasciola gigantica, as reflected by the collection sites of its 4 552 samples currently on record in the National Freshwater Snail Collection (NFSC) of South Africa. Although this species was represented in a variety of waterbodies, the majority of samples(±70%)came from rivers, brooks and dams and in 70.8% of the cases the water was described as permanent and in 71.8% as slow flowing or standing. The results of life-table studies conducted by various authors indicated that temperature should be a relatively unimportant factor in determining its geographical distribution, but that the availability of permanent water should be decisive for its presence in a given habitat. These results are in agreement with the finding that only 7.5% of the samples of this species in the NFSC were collected in habitats which were described as seasonal. Furthermore, it gives a logical explanation for the sporadic occurrence, or total absence of this species in the more arid regions of South Africa. Water impoundments and irrigation networks contribute to a large extent towards creating perennial habitats which would be suitable for L. natalensis. As intermediate host for one of the liver fluke species which already is an economic factor in South Africa, this certainly is an aspect which ought to be reckoned within the planning and construction of new irrigation schemes.


2004 ◽  
Vol 23 (3) ◽  
pp. 79-86 ◽  
Author(s):  
K. N. De Kock ◽  
C. T. Wolmarans

This paper focuses on the geographical distribution and habitats of Gyraulus connollyi, snail intermediate host of intestinal flukes of the family Echinostomatidae as reflected by the 969 collection sites on record in the database of the National Freshwater Snail Collection (NFSC) of South Africa. The presence of this species was reported from 13 different types of water-bodies, however, the highest percentage by far was collected in streams and rivers and in habitats of which the water was described as perennial, clear and fresh. A predominantly stony substratum and the presence of vegetation were also reported for the majority of habitats. The effect size was calculated for each variable to determine its importance for the occurrence of this species. An integrated decision tree constructed from the data indicated that temperature, altitude and type of water-body were the most important of the factors evaluated that could have an effect on the geographical distribution of this species. This was supported by the effect size values calculated for each variable. A temperature index calculated for each species in the database ranked G. connollyi seventh out of 53 due to its association with low temperatures. Although human echinostomosis has not yet been diagnosed in Africa, concern is expressed that G. connollyi is able to serve as first intermediate host in the transmission of echinostomosis.


2001 ◽  
Vol 20 (2) ◽  
pp. 49-53 ◽  
Author(s):  
K. N. De Kock ◽  
C. T. Wolmarans ◽  
H. D. Strauss ◽  
M. Killian

Hierdie artikel fokus op die geografiese verspreiding en die habitats van Lymnaea natalensis, die slaktussengasheer van die lewerbot, Fasciola gigantica, soos gereflekteer deur die vindplekke van sy 4 552 monsters wat tans in die Nasionale Varswaterslakversameling (NVV) van Suid-Afrika op rekord is. Alhoewel hierdie spesie in’n verskeidenheid van waterliggame aangetref is, was die meerderheid van die monsters (±70%) afkomstig vanuit riviere, spruite en damme en is die water in 70.8% van die gevalle as standhoudend en in 71.8% van die gevalle as stadigvloeiend, of staande beskryf.  Die resultate van lewenstabeleksperimente deur verskeie outeurs het daarop gedui dat temperatuur ’n minder belangrike bepalende faktor in sy geografiese verspreiding blyk te wees, maar dat die beskikbaarheid van standhoudende water deurslaggewend vir sy voorkoms in ’n gegewe habitat mag wees. Hierdie resultate strook met die bevinding dat slegs 7.5% van die monsters van hierdie spesie in die NVV in habitats wat as seisoenaal beskryf is, versamel is. Verder bied dit’n logiese verklaring vir die sporadiese voorkoms, of totale afwesigheid van hierdie spesie in die droër streke van Suid-Afrika.  Opgaardamme en besproeiingsnetwerke dra grootliks by tot die skepping van permanente habitats wat geskik sou wees vir L. natalensis.  As tussengasheer vir een van die lewerbotspesies wat reeds ’n ekonomiese faktor in Suid-Afrika is, is dit ’n aspek waarmee beslis rekening gehou behoort te word in die beplanning en konstruksie van nuwe besproeiingsprojekte.AbstractDistribution and habitats of Lymnaea natalensis, snail intermediate host of the liver fluke Fasciola gigantica, in South Africa This paper focuses on the geographical distribution and the habitats of Lymnaea natalensis, the snail intermediate host of the liver fluke, Fasciola gigantica, as reflected by the collection sites of its 4 552 samples currently on record in the National Freshwater Snail Collection (NFSC) of South Africa.  Although this species was represented in a variety of waterbodies, the majority of samples (±70%) came from rivers, brooks and dams and in 70.8% of the cases the water was described as permanent and in 71.8% as slow flowing or standing.  The results of life-table studies conducted by various authors indicated that temperature should be a relatively unimportant factor in determining its geographical distribution, but that the availability of permanent water should be decisive for its presence in a given habitat.  These results are in agreement with the finding that only 7.5% of the samples of this species in the NFSC were collected in habitats which were described as seasonal.  Furthermore, it gives a logical explanation for the sporadic occurrence, or total absence of this species in the more arid regions of South Africa. Water impoundments and irrigation networks contribute to a large extent towards creating perennial habitats which would be suitable for L. natalensis.  As intermediate host for one of the liver fluke species which already is an economic factor in South Africa, this certainly is an aspect which ought to be reckoned with in the planning and construction  of new irrigation schemes.


Author(s):  
S. Mukaratirwa ◽  
I.F. Munjere ◽  
M. Takawira ◽  
G. Chingwena

Gastrodiscosis outbreaks due to Gastrodiscus aegyptiacus were recorded in horses in the vicinity of Harare, Zimbabwe, in the absence of Bulinus forskalii, B. senegalensis and Cleopatra sp. which are considered to be the only intermediate host snails. This suggested the possibility of other snail species acting as intermediate hosts in the life cycle of the trematode. A study was carried out to determine the susceptibility of 7 freshwater snail species to infection with G. aegyptiacus. First generation (F-1) of 5 freshwater pulmonate snail species, Bulinus tropicus, Bulinus globosus, Biomphalaria pfeifferi, Helisoma dyuri and Physa acuta that were bred in the laboratory, and 2 prosobranch snail species, Melanoides tuberculata and Cleopatra sp. that were collected from the field were used in this study. Data pertaining to mortalities and cercariae shedding were recorded throughout the experimental period. The prosobranch snails, M. tuberculata and Cleopatra sp. were susceptible to G. aegyptiacus with a minimum prepatent period of 45 days and 54 days, respectively. Bulinus tropicus, P. acuta and H. duryi were susceptible as evidenced by the presence of different generations of rediae and mature cercariae on dissection at 59 days post-infection although attempts to induce the snails to shed from 28 days post-infection did not produce cercariae. Bulinus globosus and Bio. Pfeifferi were refractory to infection. The results revealed the ability of G. aegyptiacus to infect M. tuberculata, Cleopatara sp., B. tropicus, P. acuta and H. duryi under experimental conditions and this may explain the recorded outbreaks of gastrodiscosis in equine populations in Zimbabwe in the absence of the known intermediate hosts. Bulinus tropicus is considered as the most likely major intermediate host of G. aegyptiacus because of its wide distribution in Zimbabwe and is well adapted to a wide variety of environments.


2006 ◽  
Vol 25 (1) ◽  
pp. 19-31
Author(s):  
K.N. De Kock ◽  
C.T. Wolmarans

This paper focuses on the geographical distribution and habitats of Gyraulus costulatus as reflected by the 736 localities currently on record in the database of the National Freshwater Snail Collection (NFSC) of South Africa. Although a wide variety of water body types was reported for this species, the largest number of samples were yielded by rivers, streams and dams which were described as perennial with predominantly fresh and clear water. A mainly stony substrate and the presence of aquatic vegetation were recorded for the majority of localities at the time of survey. An integrated decision tree constructed from the data indicated that altitude, temperature and water bodies were the most important of the factors investigated that determined the documented geographical distribution of this species in South Africa. This was supported by the effect size values calculated separately for each factor. Since the early eighties of the previous century, surveys to monitor and update the geographical distribution of freshwater snails and snail-borne parasitic diseases have been relegated to a low priority issue and this is a matter of concern. It is recommended that the exact role of G. costulatus in the epidemiology of economically important helminth parasites in South Africa should be investigated.


2019 ◽  
Vol 94 ◽  
Author(s):  
M.P. Malatji ◽  
S. Mukaratirwa

AbstractThe main intermediate host ofFasciola giganticain sub-Saharan Africa isLymnaea(Radix)natalensis.Lymnaea(Pseudosuccinea)columellais capable of transmitting bothF. giganticaandF. hepaticaand has been reported to be present in South Africa. To date, no natural infection withF. giganticahas been reported despite the wide distribution of the snail. The aim of this study was to confirm whetherL.(P.)columellawas transmittingF. giganticaand/orF. hepaticain selected locations of KwaZulu-Natal and Eastern Cape provinces of South Africa.Lymnaea(Pseudosuccinea)columellasnails were collected from two locations in two provinces of South Africa and screened for cercariae shedding. This was followed by humanely sacrificing the screened snails, and whole tissue of each individual snail was homogenized and amplified using primers designed to amplify the ITS-1 region ofFasciolaspp. No cercariae were shed from the screened snails and molecular analysis showed that snails from the two locations were infected withF. gigantica. This study confirms natural infection ofL.(P.)columellawithF. giganticain South Africa, whereF. giganticaandF. hepaticahave already been reported to coexist. AlthoughL.(P.)columellais able to transmit the two species, surprisingly no infection withF. hepaticawas detected from the screened snails. The natural intermediate host ofF. giganticain southern Africa, including South Africa, isLymnaea(Radix)natalensisand comparative studies are needed to determine the competence of the two snail species in the transmission ofF. gigantica.


Author(s):  
Kenné N. De Kock ◽  
Cornelius T. Wolmarans

Burnupia mooiensis was already described in 1912 from specimens from the Mooi River, Potchefstroom while the oldest sample in the National Freshwater Snail Collection (NFSC) dates back to 1956. There are currently 14 species on record; however, to date the geographical distribution and habitat requirements of only two species were published. The geographical distribution of the 224 samples of B. mooiensis on record in the database of the NFSC and certain aspects of their sampling sites were analysed and the frequency of occurrence in different waterbodies, water conditions and substrata presented in tables. Data was statistically treated to determine habitat requirements. The largest percentage of samples came from rivers (57.59%), streams (18.30%) and the majority was collected in perennial habitats with stony substrata. Burnupia mooiensis is distributed mainly in the south-eastern areas of North-West, central areas of Gauteng and the south-western areas of Mpumalanga. In contrast to this, the distribution of B. capensis and B. stenochorias covers a much wider area, in spite of the fact that all three were already described by 1912 from sites in South Africa and that they share similar habitat requirements. The 14 species of Burnupia are spread over 556 different loci (0.0625°<sup>2</sup>) and therefore is one of the most widespread freshwater snail genera in South Africa. In view of its wide distribution, largely sessile, benthic lifestyle and the fact that they feed on epilithon, it is recommended that the feasibility to utilise them as bio-indicators of heavy metal pollution in waterbodies in different areas of South Africa be confirmed.


2012 ◽  
Vol 88 (1) ◽  
pp. 123-128 ◽  
Author(s):  
C.C. Appleton

AbstractNine cases of paragonimiasis have been reported from cats (4), dogs (2) and children (3) in South Africa, with an additional suspected case in an adult female patient. Details of these cases are reviewed. All nine cases, and perhaps the adult case as well, were from the province of KwaZulu-Natal but locality data are only available for six of them. These six cases represent four localities which all lie below 100 m above sea level in the province's lowlands, suggesting that there may be a focus of transmission here. The molluscan first intermediate host must be one of the two prosobranch snail species present in the area,Melanoides tuberculataorTomichia natalensis, and the decapod second intermediate host the common river crabPotamonautes sidneyi. All infected cats and dogs had pulmonary infections, while two human cases for which there is sufficient information had extrapulmonary infections. Transmission appears to be ongoing but the invasive snailTarebia graniferamay be competing with bothM. tuberculataandT. natalensis.If so, this may bring transmission to an end.


1980 ◽  
Vol 58 (7) ◽  
pp. 1390-1394 ◽  
Author(s):  
Mark A. Curtis ◽  
Manfred E. Rau

All 12 species of fishes collected from lakes on the Quebec–Labrador geosyncline and the surrounding Canadian Shield exhibited diplostomiasis. Based primarily on data from Salvelinus fontinalis, Catostomus catostomus, and C. commersoni, the infection was rare or absent in lakes with low calcium ion concentrations but apparently ubiquitous in waters high in calcium. The occurrence of this disease reflects the local distribution of the snail intermediate host Lymnaea arctica, which appears restricted to waters with calcium levels of more than about 5 ppm. Such lakes characteristically overlie rock rich in dolomite. This information suggests that the distribution of diplostomiasis in northern Quebec can be predicted from existing geological maps.


2021 ◽  
Vol 8 ◽  
Author(s):  
Mokgadi P. Malatji ◽  
Nkululeko Myende ◽  
Samson Mukaratirwa

Prosobranch snails and adult Paramphistomoidea flukes were collected from water bodies and cattle abattoir located in Mpumalanga province of South Africa, respectively. The snails were identified based on morphological characters as well as the ITS-2 and 16S markers as Melanoides sp. and Tarebia granifera, respectively, and the Paramphistomoidea flukes were identified as Calicophoron microbothrium using the ITS-1/5.8S/ITS-2 marker. After confirming identification, the snails were bred to first filial generation (F1) under laboratory conditions. Ninety snails were randomly selected from the laboratory-bred F1 snails and 25 Melanoides sp. and 20 T. granifera were exposed to C. microbothrium miracidia, and the same numbers were maintained as non-exposed controls. Results showed that C. microbothrium successfully established in Melanoides sp. and produced cercariae, and the prepatent period recorded was 21 days. Three snails shed cercariae at day 21 postexposure (PE), and rediae and free cercariae were detected in the soft tissues of one snail on dissection at day 44 PE. The same fluke did not establish in T. granifera. Melanoides sp. started producing offspring at day 7 PE, and T. granifera at day 14 PE. In conclusion, our results showed that Melanoides sp. used in this study is a suitable intermediate host for C. microbothrium under experimental conditions, and given the wide distribution of this snail species, it is important to determine its role in the natural transmission of other Calicophoron species that have been reported in South Africa.


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