First studies on the habitats of Galba truncatula (Mollusca
Contents
1. 2000 Months are indicated on each horizontal axis Revue M d V t 2002 153 3 181 188 184 MEKROUD A AND COLLABORATORS Region District Length km of areas prospected Northeastern and mean altitude Banks of rivers Affluents Road Algeria in m name of wadis and springs ditches Constantine Djebel ouahch 3 2 0 900 Oued El had El Khroub 3 7 2 750 Oued Boumerzoug Jijel Kaous 3 4 1 50 Oueds Mencha and Bou radjah Taher 2 4 l 20 Oued Djendjen Other swampy areas surveyed Djebel ouahch 3 El Khroub 2 Kaous 3 Taher 4 The wadis and road ditches were surveyed every 100 m in length TABLE I The sites surveyed in 1999 2000 in the regions of Constantine and Jijel Northeast ern In the districts of Djebel ouahch and El Khroub thirteen habitats were colonized by G truncatula only while the 4 other sites were each inhabited by G truncatula and Physella acuta Draparnaud 1805 In the districts of Kaous and Taher the numbers of habitats were 12 and 7 respecti vely data not shown The comparison of mean values bet ween the sites inhabited by G truncatula only and those colonized by the two freshwater species did not demonstrate any significant differences whatever the district and the variable studied DYNAMICS OF POPULATIONS THROUGHOUT THE YEAR Figures 3 4 and 5 show the fluctuations of three parame ters in the fours sites studied from February 2000 to January2. Fic 3 The density of Galba truncatula per m of habitat in the eight populations 2 per district from Northeastern Algeria studied from February 2000 to January 2001 summer drying of habitats Shell height mm Djebel ouahch a 6 4 3 x amp 2 FMAM J J AS O N D J Dates of monthly counts Shell helght mm Kaous c 5 4 3 2 FMAMJJ AS O N D J Dates of monthly counts Shell height mm El Khroub b 6 34 2 FMAMJJAS ON D J Dates of monthly counts Shell height mm Taher d 5 4 3 2 FMAM J J AS O N D J Dates of monthly counts Fic 4 The shell height of Galba truncatula in the eight populations 2 per district from Northeastern Algeria stu died from February 2000 to January 2001 Mean values are given with their standard deviations summer drying of habitats Revue M d V t 2002 153 3 181 188 ECOLOGY OF GALBA TRUNCATULA IN NORTHEASTERN ALGERIA 187 Percentage of snails 2 1 3 mm in height Djebel ouahch a 40 30 20 10 x OF MAMJJASOND J Dates of monthly counts Percentage of snails 2 1 3 mm in height Kaous 20 15 10 mall FMAM J J A SOND J Dates of monthly counts Percentage of snails 2 1 3 mm in height El Khroub b 40 30 20 10 0 FMAMJJASON DJ Dates of monthly counts Percentage of snalls 2 1 3 mm In height Taher d 20 15 10 LE 0 FMAM J J A SOND J Dates of monthly co
3. O F Miiller 1774 dans les zones patur es par le b tail d terminer leurs principales caract ristiques et suivre la dynamique de huit populations au cours de l ann e Trente six habitats au total ont t trouv s dans les 73 km prospect s et se situent le long des berges de rivi re dans des foss s de route ou dans des zones mar cageuses Des valeurs plus lev es dans les prairies mar cageuses ont t not es pour la superficie des g tes G truncatula et le nombre total de mol lusques alors que la densit des limn es y est plus faible que dans les deux autres types d habitats Deux p riodes de pontes ont t not es au cours de l ann e La p riode principale s tend de la fin octobre d cembre ou jan vier La seconde se situe en avril mai Jijel ou en mai juin Constantine La pr sence d un sch ma deux g n rations annuelles pour G truncatula et par suite celle de deux cycles de F hepatica Linnaeus 1758 chez la limn e au cours de l ann e doivent tre pris en consid ration pour contr ler la fasciolose dans l Alg rie du nord est MOTS CLES Alg rie Galba truncatula g n rations annuelles habitat hauteur de la coquille Lymnaeidae Mollusques in cattle was 24 2 in 1993 1994 whereas it was 8 5 in the region of Constantine unpublished data In Algeria the snail Galba truncatula O F Miiller 1774 is of major importance in transmitting fasciolosis 2 Its pre sence w
4. not demonstrate any significant variation between the eight populations studied For each population of G trun catula considered separately there were no significant diffe rences between the mean shell heights of overwintering snails noted in May June and those of spring born generation recorded in October November Discussion In the 73 km surveyed a total of 36 snail habitats were found along river banks road ditches and in marshes of Northeastern Algeria The three types of habitats correspon ded to those reported by MASSOT and SENOUCI HORR 8 in the northwestern part of this country However the total number of sites was clearly higher in the northeastern part as these last authors had only found 33 habitats in an area between Alger and the Algero Moroccan frontier This discrepancy might easily be explained by the technique of investigation used in this study every 100 m and demons trated that snail habitats were more numerous in Algeria than previously believed The other characteristics of G trunca Revue M d V t 2002 153 3 181 188 tula habitats corresponded to those reported by GOUM GHAR et al 4 in central Morocco or by DREYFUSS et al 3 and VAREILLE MOREL et al 16 in central France However two points warrant special comments First the higher areas colonized by G truncatula in swampy areas and the higher numbers of snails indicated these sites constituted the best habitats for the development of
5. performed in these four dis tricts First the habitats of G truncatula were identified in November December 1999 using the method reported by GOUMGHAR et al 4 the banks of rivers and road ditches were surveyed every 100 m along a total length of 30 km whatever the type of sites studied The same method was also used in 12 swampy areas Secondly the surface area of each snail location including places trampled by livestock the MEKROUD A AND COLLABORATORS count of snails present in each location and the calculation of the snail density per m of habitat were determined in May 2000 as all habitats were partly submerged during this per iod Finally monthly investigations were performed from February 2000 to January 2001 between day 15 and day 25 for each month in eight banks of rivers two per district each inhabited by an abundant population of G truncatula In each habitat three quadrats of 1 m2 each were randomly selected for each date of collection to count snails measure their shell heights using a calliper and verify the presence or the absence of their egg deposits After each collection the snails were put back in their habitat The variables studied in each habitat of G truncatula were the surface of each snail location the total number of snails within each habitat and the snail density per m2 of site To calculate the values of the first variable the general form of each habitat and its measurements were
6. rapidly aestivated and continued their growth only during the postsummer re sub mersion of habitats by water As G truncatula acted as an intermediate host in the life cycle of F hepatica the existence of a two generation pattern for the lymnaeid species indicated that two successive parasi Revue M d V t 2002 153 3 181 188 tic cycles could develop within snails over the year Further studies are necessary to determine the prevalences of natural infections in these populations of G truncatula over the year and to verify if overwintering snails were the most infected with F hepatica and might produce most cercariae in the field References 1 BRACKENBURRY T D and APPLETON C C Recolonization of the Umsinduri River Natal South Africa by the invasive gastropod Physa acuta Basommatophora Physidae J Med Appl Malacol 1993 5 39 44 2 BROWN D Freshwater snails of Africa and their medical impor tance Taylor amp Francis Ltd 1994 608 p London 3 DREYFUSS G VAREILLE MOREL C and RONDELAUD D Les habitats de Lymnaea truncatula Miiller Mollusque le long de deux rivi res Ann Limnol 1997 33 67 72 4 GOUMGHAR M D RONDELAUD D and BENLEMLIH M Les gites de Lymnaea truncatula Miiller au Maroc Premi res observa tions dans deux vall es d altitude situ es dans la province d Ifrane Moyen Atlas Bull Soc Fr Parasitol 1996 15 33 40 5 GOUMGHAR M D VIGNOLES P R
7. 2001 In the four populations from Djebel ouahch and El Khroub region of Constantine the numbers of G truncatula sho wed the same fluctuations over time The highest snail densi ties Figs 3a 3b were observed from December to March whereas the lowest values were noted in June and September In spite of this finding two periods of egg laying were noted in these sites The first occurred in May and or June and was Algeria followed by a slight decrease in the mean shell heights of snails Figs 4a 4b the second was noted in November December with a more marked decrease in the mean shell heights The percentages of 2 1 3 mm high snails Figs Sa 5b over the year confirmed these results In May June the increases of these percentages were slight whereas they were higher in November December This last finding indicated the overwintering generation of G truncatula was more considerable than the spring born generation In the four populations from Kaous and Taher region of Jijel two peaks in snail densities were observed The first occurred in March Fig 3c or April Fig 3d whereas the second peak was noted in November or December respecti vely Two periods of egg laying were also noted The over wintering snails laid their eggs in April May but the number of their progeny seemed low as the mean shell heights of snails Fig 4c 4d did not show any clear decreases in the subsequent months The second period was
8. ARTICLE ORIGINAL First studies on the habitats of Galba truncatula Mollusca Gastropoda Lymnaeidae the snail host of Fasciola hepatica and the dynamics of snail populations in Northeastern Algeria A MEKROUD A BENAKHA C BENLATRECHE D RONDELAUD and G DREYFUSS D partement des Sciences V t rinaires Facult des Sciences Universit de Constantine 25000 Constantine Algeria D partement Agro v t rinaire Facult des Sciences Universit d Annaba 36000 El Tarf Algeria CH U Ibn Badis and Facult de M decine Universit de Constantine 25000 Constantine Algeria UPRES EA n 3174 Facult s de M decine et de Pharmacie F 87025 Limoges Cedex Send correspondence to Dr D Rondelaud Facult de M decine F 87025 Limoges Cedex Fax 33 5 55 43 58 93 E mail rondelaud pharma unilim SUMMARY Field investigations were carried out in 1999 2001 in four districts of Northeastern Algeria regions of Constantine and Jijel to find the habitats of the snail Galba truncatula O F Miiller 1774 in areas grazed by local livestock to determine their principal characteristics and to follow up the dynamics of eight snail populations throughout the year A total of 36 habi tats were found in the 73 km surveyed along the banks of rivers road ditches or in swampy areas Higher surfaces of habitats higher numbers of snails and lower snail densities were found in swampy
9. ONDELAUD D DREYFUSS G and BENLEMLIH M Relations entre les g n ra tions annuelles de Galba truncatula Mollusca Gastropoda Lymnaeidae l altitude et la nature de ses habitats dans le centre du Maroc Rev M d V t 2001 152 457 462 6 HAMRIOUI B BELKAID M OUSSALAH S and TABET DERRAZ O Un nouveau cas de distomatose h patique en Alg rie Arch Inst Pasteur Alger 1980 54 94 96 7 HAZOUG BOEHM E CHAKER E ABDI A MOLET B KIEN T T and KREMER M La distomatose Fasciola hepatica dans le Maghreb A propos de deux cas alg riens nouveaux Arch Inst Pasteur Tunis 1979 56 105 116 188 8 MASSOT M and SENOUCI HORR K Etude de la r partition de Lymnaea truncatula dans le Nord ouest alg rien et de sa r ceptivit a Fasciola hepatica Ann Parasitol Hum Comp 1983 58 19 25 9 MOREL VAREILLE C Contribution l tude du cycle biologique de Lymnaea truncatula dans le Nord ouest du Limousin Revue M d V t 1973 124 1447 1457 10 PACENOVSKY J ZAHOR Z and KRUPICER I Prvy nalez Paramphistomum daubneyi Dinnik 1962 u hav dzieho bobytka na uzemi Alzirska Vet Med Praha 1987 32 379 384 11 PALLARY P Faune malacologique du Grand Atlas J Conchyl 1921 66 87 154 12 RUSSELL HUNTER W D Ecology of freshwater pulmonates In Pulmonates by Fretter V Peake J ed Academic Press Inc 1978 335 383 London MEKROUD A AND COLLABORATOR
10. S 13 STAT ITCF Manuel d utilisation Institut technique des c r ales et des fourrages Service des tudes statistiques 1988 210 p Boineville 14 SZMIDT ADJIDE V ADJIDE C C RONDELAUD D DREYFUSS G and MAGE C L tat des connaissances sur Fasciola hepatica Linn 1758 et Paramphistomum daubneyi Dinnik 1962 Bull Group Tech V t 1996 n 529 45 54 15 VAREILLE L VAREILLE MOREL C DREYFUSS G and RONDELAUD D L impact de quelques modifications agrono miques sur les caract ristiques des g tes limn es dans les prairies mar cageuses sur sol acide Ann Limnol 1996 32 97 104 16 VAREILLE MOREL C DREYFUSS G and RONDELAUD D The characteristics of habitats colonized by three species of Lymnaea Mollusca in swampy meadows on acid soil their interest for control of fasciolosis Ann Limnol 1999 35 173 178 Revue M d V t 2002 153 3 181 188
11. a significant effect on these characte ristics The mean surfaces F gt 33 23 31 P lt 0 001 and total numbers of snails F 33 10 54 P lt 0 001 recorded in swampy areas were significantly higher whereas snail densi ties noted in swampy areas were significantly lower F 33 4 75 P lt 0 05 The type of district had only a significant effect on snail densities with higher mean values in the dis tricts of Jijel F3 32 6 68 P lt 0 01 Revue M d V t 2002 153 3 181 188 ECOLOGY OF GALBA TRUNCATULA IN NORTHEASTERN ALGERIA 183 MEDITERRANEAN SEA Annaba Algiers JUEL Ther CONSTANTINE 3 T za Z sea N a C Reference town 100 Km r la o District studied Po C3 Cen MEDITERRANEAN SEA CONSTANTINE JIJEL fe o endjen Oued Dj Sg o EL KHROUB Snail habitat Fic 1 The geographic location of the two regions studied in Northeastern Algeria 1a and that of snail habitats in the districts of Kaous and Taher 1b or in those of Djebel ouahch and El Khroub 1c Temperature Rainfall Temperature Rainfall C mm C mm 50 100 75 150 30 60 45 90 F N 0 0 0 JFMAMJJASOND Months Months Fic 2 Meteorological diagrams showing seasonal changes of mean monthly temperature broken line and mean monthly rainfall histo grams in the region of Constantine 2a and that of Jijel 2b throughout the year
12. areas Two periods of egg laying throughout the year were noted The major period ranged from the end of October to December or January The second period occur red in April May Jijel or in May June Constantine The occurrence of a two annual generation pattern for G truncatula and consequently the development of two F hepatica Linnaeus 1758 cycles within snails over the year must be considered to control fasciolosis in Northeastern Algeria KEY WORDS Algeria annual generations Galba truncatula habitats Lymnaeidae Mollusca shell height Introduction Fasciolosis due to Fasciola hepatica Linnaeus 1758 is well known in western Maghreb as this parasitosis causes disease in man or grazing animals Human infection with liver fluke is rare in Algeria 6 7 whereas this disease is common in livestock In the district of Jijel Northeastern Algeria the prevalence of natural infections with F hepatica Revue M d V t 2002 153 3 181 188 RESUME Premi res tudes sur les habitats de Galba truncatula Mollusques Gast ropodes Lymnaeidae mollusque h te de Fasciola hepatica et la dynamique des populations dans le Nord est alg rien Par A MEKROUD A BENAKHA C BENLATRECHE D RONDELAUD et G DREYFUSS Des investigations de terrain ont t r alis es en 1999 2001 dans quatre secteurs du nord est alg rien r gions de Constantine et de Jijel pour trou ver les habitats du mollusque Galba truncatula
13. as noted since 1920 PALLARY 11 for example and was confirmed in other subsequent reports 8 10 However the distribution of snail habitats within the country was still little known In northwestern Algeria the snail was 182 living in wadis springs marshes and irrigation canals 8 whereas in the other districts no information was available As the aim of our work was to control fasciolosis and particularly the local populations of G truncatula in Northeastern Algeria preliminary studies on the habitats of this snail were necessary and the first objective of this study is to determine the characteristics of the lymnaeid habitats in the regions of this country In western Europe most populations of G truncatula show two generations successively replacing each other in the course of a year A 3 generation pattern is also known for this species and occurs mainly during very wet years 12 14 Under favourable conditions the mean growth of juvenile snails was mm per week until the seventh week of life After this date the increase in the shell height is slower to reach a full size of 11 or 12 mm on sedimentary soils 9 As the life cycle of G truncatula was not still studied in Northeastern Algeria the second objective of this study was to determine how many generations the snail might develop throughout the year To answer these questions field investi gations were carried out in the districts of Constantine and Jijel t
14. more variable and occurred from October to January Kaous or from October to December Taher This variability was also found in the shell heights as the lowest values were noted in December Fig 4c or in October Fig 4d In the sites stu died the percentages of 2 1 3 mm high snails steadily decreased from February until July and only peaked in October Fig 5c 5d Revue M d V t 2002 153 3 181 188 ECOLOGY OF GALBA TRUNCATULA IN NORTHEASTERN ALGERIA District Type of habitat Mean values S D and number per Surface area Total number Snail density type m2 of snails per m of habitat Djebel River banks 4 5 8 5 6 86 2 52 7 14 3 1 9 ouahch Swampy areas 3 16 9 7 1 193 6 97 7 11 5 2 6 El River banks 3 8 3 3 7 172 2 157 7 20 2 2 6 Khroub Road ditches 5 6 8 2 7 113 9 35 4 17 1 5 8 Swampy areas 2 18 8 8 7 220 7 52 0 12 4 2 8 Kaous River banks 3 7 0 1 0 166 3 79 1 23 1 4 0 Road ditches 2 5 2 2 7 130 7 10 5 24 8 1 1 Swampy areas 3 40 6 15 0 715 1 289 4 17 4 3 5 Taher River banks 3 7 7 2 2 189 6 41 1 25 3 2 0 Road ditches 4 5 0 2 5 125 7 66 8 25 1 1 4 Swampy areas 4 24 5 9 3 375 6 82 6 17 3 8 6 TABLE II The principal characteristics of Galba truncatula habitats in the regions of Constantine Djebel ouahch El khroub and Jijel Kaous Taher Northeastern Algeria Comparison of mean shell heights in March April and May did
15. o find snail habitats in areas grazed by local livestock determine their principal characteristics and follow up the dynamics of snail populations throughout the year Materials and methods The location of the four districts surveyed in Northeastern Algeria the different types of sites investigated in each dis trict and their lengths are given in Figure 1 and Table I The first two districts Kaous and Taher were located in the region of Jijel altitude 30 50 m whereas the other two Djebel ouahch and El Khroub were situated in the region of Constantine altitude 750 900 m These districts were chosen for snail studies as natural infections of cattle with F hepatica were detected in a previous study unpublished data The geographic distance between the region of Constantine and that of Jijel is 120 km The subsoil of these four districts is constituted with limes tone In the districts of Kaous and Taher the climate is medi terranean with a mean monthly temperature ranging from 9 5 to 26 6 C and a mean annual rainfall of 632 mm Fig 2a In the other two the climate is semiarid with a mean monthly temperature ranging from 4 6 to 26 9 C anda mean annual rainfall of 373 mm Fig 2b However in the four districts the rainy season mainly occurs during winter months and also in May a mean of 95 3 mm of rainfall for this month in the region of Constantine and 84 4 mm in that of Jijel Three distinct operations were
16. reported on a map before a subsequent cutout of the drawing obtained into geo metrical figures and the determination of their individual sur faces The dynamics of snail populations throughout the year was analyzed via the number of snails per m of habitat their mean shell height and the percentage of young snails measu ring 2 1 to 3 mm in height This last category of snails was chosen for this study as they were preadults These three variables were chosen to identify the number of annual gene rations for G truncatula according to the method used by GOUMGHAR et al 5 in central Morocco Mean values and standard deviations were calculated from the individual values recorded for each variable taking into account the geographical district and the date of snail collection A two way analysis of variance 13 was used to establish levels of significance Results NUMBER AND CHARACTERISTICS OF SNAIL HABI TATS Seventeen habitats of G truncatula Table II were found in the 40 km surveyed in the region of Constantine 7 on river banks 5 in road ditches and the 5 others in swampy areas In the 33 km investigated in the region of Jijel a total of 19 habitats was noted with 6 located on river banks 6 in road ditches and the 9 others in swampy areas All popula tions of G truncatula were found to be isolated from each other with no overlap The characteristics of snail habitats are given in Table II The type of habitat had
17. snail populations As the values recorded in the marshes of Jijel were significantly greater than those found in the districts of Djebel ouahch and El Khroub the swampy areas of the former region seemed to offer more suitable conditions to the snails probably because of milder climatic variations in the lowland region of Jijel It would be of interest to determine the impact of such condi tions on the prevalences of natural infections with F hepatica in snails Secondly the absence of significant differences bet ween the mean values recorded in the sites inhabited by G truncatula only and those colonized by G truncatula and P acuta suggested the relationships between the two species in these last communities would be well balanced and that P acuta would have lost its invasive character in these habitats as this last species was known to colonize actively rivers on South Africa 1 or open drainage systems in central France 15 185 186 Number of snails per m2 of habitat Djebel ouahch a 56 42 28 14 x 0 F MAMJ JA SOND J Dates of monthly counts Number of snails per m2 of habitat Kaous c 70 66 42 28 0 FMAMJ JA S O N D J Dates of monthly counts MEKROUD A AND COLLABORATORS Number of snails per m2 of habitat El Khroub b a FMAMJ J AS O N D J Dates of monthly counts Number of snails per m2 of habitat Taher 70 66 42 28 14 OF MAMJJASOND J Dates of monthly counts
18. unts Fic 5 The percentage of young Galba truncatula measuring 2 1 to 3 mm in height in the eight populations studied from February 2000 to January 2001 summer drying of habitats Despite some slight fluctuations in the dates of both egg laying periods the two generation pattern per year found for G truncatula in the regions of Constantine and Jijel verified the first observations that MASSOT and SENOUCI HORR 8 had reported in northwestern Algeria They also agreed with the observations that several authors 9 12 had made in western Europe Snails from the autumn born generation can overwinter contribute to the next year s breeding season in spring and end their life in May or June before summer drying of habitats On the other hand the spring born gene ration can aestivate and lay egg deposits in autumn before subsequent death of snails at the end of the year In spite of this similarity in these findings two points found in this study warrant special comments First the longer durations of the main egg laying period and the higher snail densities of overwintering snails found in the eight populations of G truncatula see Fig 3 might be easily explained by the tem perate climatic conditions which occurred in autumn and winter Secondly the deposits of eggs by overwintering snails in May June and the subsequent growth of their pro geny were disturbed by the onset of summer drying from June so that many juvenile snails
Download Pdf Manuals
Related Search