Release of Lungworm Larvae from Snails in the Environment: Potential for Alternative Transmission Pathways

Background: Gastropod-borne parasites may cause debilitating clinical conditions in animals and humans following the consumption of infected intermediate or paratenic hosts. However, the ingestion of fresh vegetables contaminated by snail mucus and/or water has also been proposed as a source of the infection for some zoonotic metastrongyloids (e.g., Angiostrongylus cantonensis). In the meantime, the feline lungworms Aelurostrongylus abstrusus and Troglostrongylus brevior are increasingly spreading among cat populations, along with their gastropod intermediate hosts. The aim of this study was to assess the potential of alternative transmission pathways for A. abstrusus and T. brevior L3 via the mucus of infected Helix aspersa snails and the water where gastropods died. In addition, the histological examination of snail specimens provided information on the larval localization and inflammatory reactions in the intermediate host. Methodology/Principal Findings: Twenty-four specimens of H. aspersa received ~500 L1 of A. abstrusus and T. brevior, and were assigned to six study groups. Snails were subjected to different mechanical and chemical stimuli throughout 20 days in order to elicit the production of mucus. At the end of the study, gastropods were submerged in tap water and the sediment was observed for lungworm larvae for three consecutive days. Finally, snails were artificially digested and recovered larvae were counted and morphologically and molecularly identified. The anatomical localization of A. abstrusus and T. brevior larvae within snail tissues was investigated by histology. L3 were detected in the snail mucus (i.e., 37 A. abstrusus and 19 T. brevior) and in the sediment of submerged specimens (172 A. abstrusus and 39 T. brevior). Following the artificial digestion of H. aspersa snails, a mean number of 127.8 A. abstrusus and 60.3 T. brevior larvae were recovered. The number of snail sections positive for A. abstrusus was higher than those for T. brevior. Conclusions: Results of this study indicate that A. abstrusus and T. brevior infective L3 are shed in the mucus of H. aspersa or in water where infected gastropods had died submerged. Both elimination pathways may represent alternative route(s) of environmental contamination and source of the infection for these nematodes under field conditions and may significantly affect the epidemiology of feline lungworms. Considering that snails may act as intermediate hosts for other metastrongyloid species, the environmental contamination by mucus-released larvae is discussed in a broader context

Evaluation of active ingredients and nematodes against slugs and snails on organic lettuce

Three years trials were carried out to evaluate the efficacy of some molluscicides for the control of slugs (Arion sp.) and snails (Cepaea nemoralis and Helix aspersa) on organic lettuce in Emilia-Romagna (Italy). Iron phosphate has proven to be as effective as those based on metaldehyde. The nematodes Phasmarabditis hermaphrodita did not work against individuals as big as those employed in the trials

Effect of humus supplement on growth, digestibility and nutritional efficiency of juvenile Helix aspersa snail

El humus es importante en la dieta de Helix aspersa y de otras especies de caracoles comestibles aunque su contribución nutricional es poco conocida. En el presente trabajo se evalúa el efecto de un suplemento con humus sobre el crecimiento, eficiencia nutricional y digestibilidad del caracol H. aspersa durante la fase juvenil. El experimento se hizo en laboratorio usando un diseño completamente al azar con dos tratamientos (dietas) con diez repeticiones de veinte caracoles: dieta I, concentrado comercial para gallinas ponedoras; dieta II, concentrado comercial para gallinas ponedoras más un suplemento con humus comercial de lombriz. Cuando los caracoles juveniles H. aspersa crecen en presencia de humus lo consumen regularmente y aumentan la velocidad de crecimiento (478.71±8.26 mg sin humus, dieta I; 912.21±9.42 mg con humus, dieta II; p≤0.01). El humus también aumenta la disponibilidad de los nutrientes orgánicos de la dieta, mejorando la digestibilidad de la materia seca (54.21±2.12% sin humus, dieta I; 80.13±1.37% con humus, dieta II; p≤0.001), energía bruta (56.32±3.13% sin humus, dieta I; 65.56±4.21% con humus, dieta II; p≤0.001), proteína cruda (63.14±3.41% sin humus, dieta I; 74.56±2.82% con humus; dieta II; p≤0.01), fibra detergente neutro (56.68±4.84% sin humus, dieta I; 66.64±3.21% con humus, dieta II; p≤0.01) y fibra detergente ácido (35.32±3.32% sin humus, dieta I; 47.42±2.13% con humus, dieta II; p≤0.001). Por tanto, se mejoró la razón de conversión alimenticia (1.12±0.14 sin humus, dieta I; 0.78±0.11 con humus, dieta II; p≤0.01) y la razón de eficiencia proteica (6.40±0.09 sin humus, dieta I; 11.09±0.15 con humus, dieta II; p≤0.01).Humus is important in the diet of Helix aspersa and other species of edible snails although its nutritional contribution is not well known. In this study the effect of a humus supplement on the growth, nutritional efficiency and digestibility of the snail H. aspersa in its juvenile stage was evaluated. The experiment was done under laboratory conditions using a completely randomized design with two treatments (diets) with ten replications of 20 snails: Diet I, commercial concentrate for laying hens; Diet II, the same commercial concentrate plus a commercial humus supplement for earthworms. When H. aspersa juvenile snails grow in the presence of humus, they feed regularly on the supplement and grow significantly faster (478.71±8.26 mg without humus, diet I; 912.21±9.42 mg with humus, diet II; p≤0.01). Humus also increases the availability of the diet’s organic nutrients, improving digestibility of dry matter (54.21±2.12% without humus, diet I; 80.13±1.37% with humus, diet II; p≤0.001), raw energy (56.32±3.13% without humus, diet I; 65.56±4.21% with humus, diet II; p≤0.001), crude protein (63.14±3.41% without humus, diet I; 74.56±2.82% with humus; diet II; p≤0.01), neutral detergent fiber (56.68±4.84% without humus, diet I; 66.64±3.21% with humus, diet II; p≤0.01) and acidic detergent fiber (35.32±3.32% without humus, diet I; 47.42±2.13% with humus, diet II; p≤0.001). Therefore, the feed conversion ratio was improved (1.12±0.14 without humus, diet I; 0.78±0.11 with humus, diet II; p≤0.01) and the protein efficiency ratio (6.40±0.09 without humus, diet I; 11.09±0.15 with humus, diet II; p≤0.01)

Habitat selection in terrestrial snails and its applications to heliciculture

Snails are employed as experimental animals in different scientific fields and their growth is a good biological indicator. Growth is mainly determined at a genetic level, although many factors biotic and abiotic may alter growth rates. One of these factors is habitat selection. Nevertheless the knowledge about the cha-racteristics that determines habitat selection are not considered in the design of installations, management of farms or raising snails. In this way, the aim of this paper is synthesize the different components of habitat that influence habitat choice of terrestrial snails. On the other hand, it proposes premises that would be considered in design of installations.El crecimiento de los caracoles terrestres que, además de como animales productivos, se utilizan como animales de experimentación es considerado un buen indicador biológico. Aunque el crecimiento está genéticamente determinado, muchos factores pueden modificarlo, uno de ellos es la selección de hábitat. Sin embargo, los conocimientos sobre las condiciones que la determinan no se suelen incorporar al diseño de instalaciones, manejo de los criaderos o la producción helicícola. En este trabajo se revisan aquellas condiciones que determinan la selección de microhábitat en caracoles terrestres y se proponen medidas que deberían ser consideradas en el diseño de instalaciones

Draft genome sequence of Weissella viridescens UCO-SMC3, isolated from the slime of helix aspersa Müller snails

This report describes the draft genome sequence of Weissella viridescens UCO-SMC3, isolated from Helix aspersa Müller slime. The reads were generated by a whole-genome sequencing (WGS) strategy on an Illumina MiSeq sequencer and were assembled into contigs with a total estimated size of 1,612,814 bp. A total of 2,455 genes were predicted, including 2,301 protein-coding sequences. The draft genome sequence of W. viridescens UCO-SMC3 will be useful for further studies of specific genetic features and for understanding the mechanisms of its beneficial properties in the skin.Fil: Garcia Cancino, Apolinaria. Universidad de Concepción; ChileFil: Albarracín, Leonardo Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán; Argentina. Tohoku University; JapónFil: Espinoza Monje, Marcela. Universidad de Concepción; ChileFil: Campos Martin, Jorge. Universidad de Concepción; ChileFil: Garcia Castillo,Valeria. Tohoku University; Japón. Universidad de Concepción; ChileFil: Nakano, Yukha. Tohoku University; JapónFil: Ikeda Ohtsubo, Wakako. Tohoku University; JapónFil: Gutierrez, Cristian. Universidad de Concepción; ChileFil: Morita, Hidetoshi. Okayama University; JapónFil: Kitazawa, Haruki. Tohoku University; JapónFil: Villena, Julio Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Tohoku University; Japó

Effect of population density on size of edible snail helix aspersa müller

An assessment was made of the effects of population density on Helix aspersa Müller snails at their nursery stage. A sample of 3420 animals was used, grouped at eighteen density levels: from 600 to 11100 snails/m2. The results demonstrate that higher population density decreased growth (p<0.001). Furthermore the optimum snail population density at the nursery stage ranged from 600 to 4300 snails/m2.Se estudia el efecto de la densidad sobre el tamaño del Helix aspersa Müller durante la primera fase de crecimiento. Se utilizan 18 niveles de densidad entre 600 a 11100 animales/m2. Los resultados indican la existencia de diferencias significativas en el crecimiento según el nivel de densidad (p<0,001), de modo que a medida que se incrementa la densidad disminuye el tamaño. La densidad óptima, en primera edad, oscila entre 600 y 4300 animales/m2

Relationship between microspatial population genetic structure and habitat heterogeneity in Pomatias elegans (O.F. Müller 1774) (Caenogastropoda, Pomatiasidae)

In the present study the population genetic structure of the terrestrial snail Pomatias elegans was related to habitat structure on a microspatial scale. The genetic variability of 1607 individuals from 51 sampling sites in five different populations in Provence, France, was studied with an allozyme marker using population genetic methods, Mantel tests and spatial autocorrelation techniques were applied to different connectivity networks accounting for the structural features of the landscape. It is suggested that the population structure is, to a large extent, a function of the habitat quality, quantified as population density, and of the spatial arrangement of the habitat in the landscape and not of the geographical distance per se. In fragmented habitats, random genetic drift was the prevailing force for sampling sites separated by a few hundred meters

Snail meat: Significance and consumption

The consumption of snail meat goes back to prehistoric times. Different ancient nations had snails on their menu, but Helices culture as a productive activity was born as a Roman culture. Some of the most economically important edible species are: Helix aspersa (Mtiller) Helixpomatia (Linne), Helix iucorum (Linne), Helix aperta (Born), Eobania vermiculata (Miiller). Together with its tasie, snail meat has several advantages over others: quite low lipid rate and calorie values versus rich mineral, essential amino acid and fatty acid content. The composition of snail meat is presented. In addition, the composition of different snail species and the part analyzed (pedal mass and visceral mass) is presented. Also, the differences in composition according to the species (snail meat horse/chicken meat, beef, swine meat, fish meat) are presented. The French are the world's leading consumers of snails. !n France snails come to market in a variety of ways. Estimated consumption of snails in France is around 40 000 tones/year. Total French imports account for 25% of world imports. France is also the leading exporter of prepared snails, mainly sold as preserved snails and prepared dishes. Snail imports have been much higher than exports (65 tones exported in 2002. vs. 2.700 tones imported). Despite the large consumption, only 3% of snails in France come from production (farming). Italy is in second place in the world consumption of snails, and Spain and Germany are in the third and fourth place. The development of snails consumption in Italy is followed with the same amount of production of snails in the whole biological circle. In 2001, from 24,700 tons, 9,350 tons (37.8%) came from production, 6 00 tons (2.4%) came from nature, and 14,750 tons (59.70%) came from imports (frozen, fresh and prepared snails). In Serbia, at the beginning of 2005, we had over 400 registered farms for snail production