Occurrence of a sibling species complex within neotropical lymnaeids, snail intermediate hosts of fascioliasis

Section: Discussionmentioning

confidence: 99%

The use of the polymerase chain reaction and restriction fragment length polymorphism technique associated with the classical morphology for characterization of Lymnaea columella, L. viatrix, and L. diaphana (Mollusca: Lymnaeidae)

Carvalho

Cardoso

Lira

et al. 2004

“…In contrast, this study was able to clearly distinguish between the two taxa using characters of the male reproductive system. The validity of these anatomical markers has been confirmed by a genetic variability analysis based on 12 enzyme loci (Durand et al 2002) and by the analysis of several DNA sequences such as the small subunit (18S) gene, internal transcribed spacers (1 and 2) and the cytochrome c oxidase subunit I (Bargues et al 2007). …”

Section: Morphological Identification Of Lymnaeidsmentioning

confidence: 94%

Distribution of Lymnaeidae (Mollusca: Pulmonata), intermediate snail hosts of Fasciola hepatica in Venezuela

Pointier

Noya

et al. 2009

An extensive malacological survey was carried out between [2005][2006][2007][2008][2009] Fascioliasis is a parasitosis mainly infecting cattle, but it is now considered to be an emergent disease in humans in many countries over the world (Mas-Coma 2005). In the New World, it is considered as a serious health problem in several Andean countries. Bolivia is even described as a hyperendemic area and one of its epidemiological characteristics is its very high altitude at more than 4,000 m . The timing of the emergence of human foci in the Altiplano Region corresponds to the invasion by the European intermediate snail host Lymnaea truncatula (Jabbour-Zahab et al. 1997, Meunier et al. 2001. In Venezuela, human fascioliasis was first reported in 1910 and only eight sporadic cases were detected in the following decades (Risquez 1929, Rodríguez & González 1975, Abdul-Hadi et al. 1996, Scorza et al. 1999, Incani et al. 2002, Alarcón de Noya et al. 2006). However, in 2005 five children belonging to the same family were detected with fascioliasis in Timotes, in the Venezuelan Andes, at an altitude of 2,230 m (Alarcón de Noya et al. 2007). The same year a malacological survey carried out in the Timotes area found only a single lymnaeid species, the European L. truncatula. In this paper we present the results of an extensive malacological survey which was carried out A malacological survey was carried out between 2005-2009 across the whole country. A total of 298 sites were sampled (see the inserts in the maps showing all the sampling sites). Snails were sampled from different vegetation either by hand or sampled using a scoop mounted with a wooden handle, depending on the type of site. These sites include the following main habitat types: springs, ditches, brooks, canals, rivers, swamps, tanks, ponds and lakes. Following field collection lymnaeid snails were allowed to relax overnight using menthol. They were then immersed for 40 s in water at 70°C, from which they were transferred to water at RT. The soft parts were drawn from the shell with small forceps and fixed in slightly modified Railliet-Henry fluid (distilled water 930 mL, sodium chloride 6 g, formalin 50 mL, glacial acetic acid 20 mL). Shells were measured to the nearest 1 mm using callipers. Snails preserved in Railliet Henry's fluid were dissected under a stereoscopic microscope and drawings of the reproductive system were made using a camera lucida attachment. Snails were identified according to conchological and anatomical characteristics

Section: Abstract: Neotropical Lymnaeids -Sibling Species -Lymnaea Cmentioning

confidence: 99%

“…This last species has now a very large distribution in all tropical countries particularly in the neotropical area (see Malek & Chrosciechowski 1964, Paraense 1982b, Gomez et al 1986). Two other species may be added to that list (i) L. truncatula (Müller, 1774) from Europe which recently invaded several Andean countries (Oviedo et al 1995, Jabbour-Zahab et al 1997, Durand et al 2002; (ii) L. plicata Hylton-Scott, 1953 from Chubut Province, Argentina which validity has not yet been confirmed.The morphology of the shell and reproductive system of five of those species has been well studied and allows a clear identification (Paraense 1982a, 1984, 1986, 1995, Samadi et al 2000, Pointier et al 2004 Moreover, an analysis of the genetic variability based on 12 enzyme loci revealed different fixed alleles at nine loci between two syntopic samples of L. viatrix var. elongata at the type locality in Lima, Peru (Durand et al 2002).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Anatomical studies of sibling species within neotropical lymnaeids, snail intermediate hosts of fascioliasis

Pointier

Cazzaniga

González‐Salas

et al. 2006

Several anatomical parameters of the reproductive system have been used to distinguish Key words: Neotropical lymnaeids -sibling species -Lymnaea cubensis -Lymnaea viatrixEleven species of lymnaeid snails have been described in the Caribbean area and South America. However, only six species are considered as valid by Hubendick (1951) and Paraense (1976Paraense ( , 1982aParaense ( , 1983Paraense ( , 1984Paraense ( , 1986Paraense ( , 1994Paraense ( , 1995: Paraense, 1982 and L. columella Say, 1817. This last species has now a very large distribution in all tropical countries particularly in the neotropical area (see Malek & Chrosciechowski 1964, Paraense 1982b, Gomez et al. 1986). Two other species may be added to that list (i) L. truncatula (Müller, 1774) from Europe which recently invaded several Andean countries (Oviedo et al. 1995, Jabbour-Zahab et al. 1997, Durand et al. 2002; (ii) L. plicata Hylton-Scott, 1953 from Chubut Province, Argentina which validity has not yet been confirmed.The morphology of the shell and reproductive system of five of those species has been well studied and allows a clear identification (Paraense 1982a, 1984, 1986, 1995, Samadi et al. 2000, Pointier et al. 2004 Moreover, an analysis of the genetic variability based on 12 enzyme loci revealed different fixed alleles at nine loci between two syntopic samples of L. viatrix var. elongata at the type locality in Lima, Peru (Durand et al. 2002). The absence of heterozygotes within this locality thus indicated the presence of isolated populations or cryptic species within the variety elongata. In the same study, Durand et al. (2002) also found significant genetic differences between the two taxa from Lima and another population sampled in Bahia Blanca, Argentina, located about 350 km to the north of the type locality for L. viatrix var. ventricosa. More recently, the use of several molecular markers (PCR-RLFP analysis of the ITS1 and ITS2 rDNA and 16S rDNAmt using 12 restriction enzymes) in a study of several populations morphologically identified as L. viatrix from Brazil, Uruguay, and Argentina showed a high level of genetic polymorphism between populations which was interpreted as an intra-specific variation (Carvalho et al. 2004).A morphological comparison of several populations of L. cubensis from the Caribbean area and several populations of the introduced L. truncatula from Bolivia was carried out by Samadi et al. (2000) using several conchological and anatomical characters of the reproductive system. The conchological study showed the presence of a large amount of variability within and between populations that did not allow distinction between taxa. The analysis of anatomical parameters of the reproductive system also showed a high variability, but all these characters clearly separated L. cubensis from L. truncatula independently from their geographical origin. In the present paper, we use these anatomical characters in the same way to see if it is possible to distinguish morphologically L. cubensis from L. viatrix. The materia...