Variation of snail's abundance in two water bodies harboring strains of Pseudosuccinea columella resistant and susceptible to Fasciola hepatica miracidial infection, in Pinar del Río Province, Cuba

Abstract

The abundance of freshwater snails in two rural sites of Pinar del Río, Cuba, which harbor Pseudosuccinea columella susceptible and resistant to miracidia of Fasciola hepatica was followed for one year. Susceptible snails were found in the most anthropic site (IPA) Key words: Pseudosuccinea columella -Lymnaeidae -freshwater snails -Fasciola hepatica -abundance -diversity -resistancesusceptibility -CubaIn Cuba two Lymnaeid snails, Fossaria cubensis and Pseudosuccinea columella, act as intermediate hosts in the life cycle of the digenean parasite Fasciola hepatica, although only the former has been found naturally infected. Nonetheless, high infection rates for P. columella have been observed in laboratory exposures. In addition, natural infection has been reported in Argentina, Brazil, and Australia (Ueta 1980, Boray et al. 1985, Oliveira et al. 2002, Prepelitchi et al. 2003. Recently, several populations of P. columella were reported to show no susceptibility (i.e. resistance) to miracidia of F. hepatica and some studies were conducted in order to compare various traits between resistant and susceptible snails under laboratory conditions (Gutiérrez et al. 2002, 2003a, b, Calienes et al. 2004). However, due to the disappearance of resistant populations from their original sampling sites, no study including resistant P. columella had been conducted so far under natural conditions. One site recently surveyed (El Azufre) harbors a population of resistant snails which seem to thrive in a more stable environment (Calienes et al. 2004). The present study was conducted with the objective of providing data on the variation of abundance throughout a year of resistant (for the first time) and sus-+ Corresponding author. E-mail: pcolumella@yahoo.es The work was carried out in the village of San Andrés, La Palma municipality, Pinar del Río province. Two sampling sites were selected ( Fig. 1): El Azufre, a spring source which shows little signs of human activity, and IPA, a small canal whose waters are drained from a dam located close to the IPA (Instituto Politécnico Agropecuario) school and where sheep and cows are seen grazing everyday. Both sites are separated 1.85 km from each other. The samplings were performed by collecting snails with a sieve and forceps, always by the same collector during 15 min; the abundance was measured as the number of snails collected per 15-min sampling. A total of 22 and 20 samplings were made in IPA and El Azufre respectively from

Natural Infection with Fasciola hepatica in Host-Snails and Cattle in Ten Dairy Farms from a Western Municipality in Cuba

“…Galba cubensis have been found as a dominant species in low diversity habitats, whereas in highly diverse ecosystems it may occur with low abundance (39). Interestingly, G. cubensis populations were found in all dairies studied, while P. columella was found in two livestock, which enhances the idea of the former being the main agent responsible for fasciolosis in Cuba (6,7,11,40).…”

“…Although P. columella has been found only in two sites, it does not diminish its importance as a transmitter of F. hepatica. Its role in the transmission of fasciolosis has been referred in laboratory conditions (6,11,41) and recently in nature for the first time in Cuba and the Caribbean (8). Natural infection of this species has also been reported in other countries like Brazil, Australia, and Argentina (42,43), and it was introduced in France with the possibility of transmission capacity (44).…”

“…A total of 50 snails were collected from each bovine livestock farm using forceps and sieves (11). The mollusks were kept in moist conditions and taken to the Malacology Laboratory at the Institute of Tropical Medicine where they were subsequently dissected to identify larval stages of F. hepatica.…”

“…In Cuba, there are only two types of lymnaeid snails, Galba cubensis and Pseudosuccinea columella, whose susceptibility to F. hepatica infection has been proved (6-8), and their settlement in subtropical areas is favored by the high moisture associated with frequent rainfall and moderate temperatures. Other malacological studies (7,(9)(10)(11) have been carried out in Cuba, which made it possible to understand the biology and population dynamics of lymnaeid snails.…”

Fasciola hepaticain Cuba: compatibility of different isolates with two intermediate snail hosts,Galba cubensisandPseudosuccinea columella

“…Among them, Fasciola hepatica (the common liver fluke) is the species which has the largest geographical distribution and the widest definitive-host spectrum, and which is the main cause of human infections (Hurtrez-Boussès et al, 2001;Mas-Coma et al, 2009). Lymnaeid snails have been subjected to many studies (taxonomical, ecological and parasitological) regarding their role as intermediate hosts of parasites with medical and veterinary importance, and particularly for their involvement in fascioliasis transmission (Bargues & Mas-Coma, 1997;Gutiérrez et al, 2000Gutiérrez et al, , 2005Rondelaud et al, 2004;Correa et al, 2011). Indeed, about 20 species of lymnaeids have been described to host F. hepatica (Correa et al, 2010).…”