Antonio A. Vázquez

First record of the invasive land snail Achatina (Lissachatina) fulica (Bowdich, 1822) (Gastropoda: Achatinidae), vector of Angiostrongylus cantonensis (Nematoda: Angiostrongylidae), in Havana, Cuba

The giant African snail, Achatina (Lissachatina) fulica (Bowdich 1822), is considered one of the worst invasive alien species in the world. This mollusc is also a concern to public health because it can serve as an intermediate host of the rat lungworm, Angiostrongylus cantonensis, a causative agent of eosinophilic meningoencephalitis in humans. This is the first record of A. fulica in Cuba, where it is found in an urban area of Havana where it has become established in an area of about 1 km². Parasitological analyses revealed that all A. fulica were infected with An. cantonensis with an average 50 third-stage larvae in 3 cm² of snail mantle. The eventual spread of A. fulica to other regions in Cuba through natural or human-mediated ways could result in damage to autochthonous flora and fauna as well as becoming a serious issue for public health and the economy.

Isolation, characterization and population-genetic analysis of microsatellite loci in the freshwater snail Galba cubensis (Lymnaeidae)

The freshwater snail Galba cubensis (Pfeiffer, 1839) has a large distribution in the Americas. Despite being an intermediate host of Fasciola hepatica—the trematode causing fasciolosis in livestock and humans—its population genetics have never been studied. We isolated and characterized 15 microsatellite loci in G. cubensis to evaluate its genetic diversity, population-genetic structure and mating system. We tested the microsatellite loci in 359 individuals from 13 populations of G. cubensis from Cuba, Guadeloupe, Martinique, Puerto Rico, Venezuela, Colombia and Ecuador. We also tested cross-amplification in three closely related species: G. truncatula, G. viator and G. neotropica. We found that G. cubensis has a similar population structure to other selfing lymnaeids that live in temporary habitats: low genetic diversity, large departure from Hardy-Weinberg equilibrium, marked population structure and high selfing rate. We found that seven and six loci amplified in G. truncatula and G. viator, respectively, and that all 15 loci amplified in G. neotropica. This last finding suggests a close relatedness between G. cubensis and G. neotropica, probably being conspecific and synonymous. This new set of microsatellite markers will be a useful tool to study the genetic diversity of this snail species across a large geographical range and, consequently, to understand the emergence and re-emergence of fasciolosis in the Americas.

Facilitated invasion of an overseas invader: human mediated settlement and expansion of the giant African snail, Lissachatina fulica , in Cuba

The giant African snail, Lissachatina fulica, is considered one of the most invasive species worldwide, acting as a crop pest and diseases vector. It was first detected in Cuba in 2014 and is dispersing throughout Havana. We mapped 34 sites in the vicinity of Havana to assess its spread and analysed ecological (forestation and humidity) and anthropogenic (pollution and religious sites) factors in relation to the presence/absence of the snails using multivariate correspondence analysis. There were 14 sites at which the snail was present and where religious rituals of the Yoruba creed, an African rooted religion, were observed. No other variables showed significant relationships. This indicates that the rituals may be a major factor in the dispersal of the snail in Havana and more widely in Cuba. In light of this an outreach program with key Yoruba leaders may help in slowing the dispersal of the snail within Cuba, once the threats posed by this species are known.

A multiplex PCR for the detection of Fasciola hepatica in the intermediate snail host Galba cubensis.

Fasciolosis is a snail-borne trematode infection that has re-emerged as a human disease, and is considered a significant problem for veterinary medicine worldwide. The evaluation of the transmission risk of fasciolosis as well as the efficacy of the strategies for its control could be carried out through epidemiological surveillance of the snails that act as intermediate hosts of the parasites. The present study aimed to develop the first multiplex PCR to detect Fasciola hepatica in Galba cubensis, an important intermediate host of the parasite in the Americas and especially in the Caribbean basin. The multiplex PCR was optimized for the amplification of a 340 bp fragment of the second internal transcribed spacer (ITS-2) of F. hepatica rDNA, while another set of primers was designed and used to amplify a conserved segment of the nuclear 18S rDNA of the snail (451 bp), as an internal control of the reaction. The assay was able to detect up to 100 pg of the parasite even at high concentrations of snail DNA, an analytical sensitivity that allows the detection of less than a single miracidium, which is the minimal biological infestation unit. A controlled laboratory-reared G. cubensis - F. hepatica system was used for the evaluation of the developed multiplex PCR, and 100% sensitivity and specificity was achieved. This assay constitutes a novel, useful and suitable technique for the survey of fasciolosis transmission through one of the main intermediate hosts in the Western hemisphere.

Impact of Human Activities on Fasciolosis Transmission

Fasciolosis is a worldwide disease caused by the liver fluke Fasciola spp. This food- and water-borne disease is a major public health and veterinary issue. It is currently (re)emerging in several regions mainly due to the rapid evolution of human activities. This article reviews the current knowledge of the impact of irrigation-system management, livestock management, and human diet and hygiene habits on the emergence of fasciolosis. We also identify the gaps in this knowledge and the possible solutions for limiting these impacts. Integrated control seems to be the most effective solution for controlling fasciolosis, because it enables monitoring, prevention, and rapid action in case of the (re)emergence of the disease.

Fasciola hepatica - Pseudosuccinea columella interaction: effect of increasing parasite doses, successive exposures and geographical origin on the infection outcome of susceptible and naturally-resistant snails from Cuba

BackgroundPseudosuccinea columella is one of the most widespread vectors of Fasciola hepatica, a globally distributed trematode that affects humans, livestock and wildlife. The exclusive occurrence in Cuba of susceptible and naturally-resistant populations to F. hepatica within this snail species, offers a fascinating model for evolutionary biology, health sciences and vector control strategies. In particular, resistance in P. columella is characterized by the encapsulation of the parasite by host’s immune cells and has been experimentally tested using different Cuban F. hepatica isolates with no records of successful infection. Here, we aimed to explore for the first time, the effect of different parasite doses, successive exposures and different parasite origins on the infection outcomes of the two phenotypes of P. columella occurring in Cuba.MethodsTo increase the chances for F. hepatica to establish, we challenged Cuban P. columella with increasing single parasite doses of 5, 15 or 30 miracidia and serial exposures (three-times) of 5 miracidia using a sympatric F. hepatica isolate from Cuba, previously characterized by microsatellite markers. Additionally, we exposed the snails to F. hepatica from different geographical origins (i.e. Dominican Republic and France). Parasite prevalence, redial burden and survival of snails were recorded at 25 days post-exposure.ResultsNo parasite development was noted in snails from the resistant populations independent of the experimental approach. Contrastingly, an overall increase in prevalence and redial burden was observed in susceptible snails when infected with high miracidia doses and after serial exposures. Significant differences in redial burden between single 15 miracidia and serial 3 × 5 miracidia infected snails suggest that immune priming potentially occurs in susceptible P. columella. Compatibility differences of allopatric (Caribbean vs European) F. hepatica with susceptible snails were related to the geographical scale of the combinations.ConclusionsHere, the effectiveness of P. columella resistance to F. hepatica does not decline with increasing parasite doses, successive infection or different geographical origins of parasite isolates, while presenting new evidence for specificity for infection in susceptible P. columella snails. Understanding the peculiarities of the P. columella-F. hepatica interaction and the extent of the resistant phenotype is crucial for an effective parasite control and for developing alternatives to tackle fasciolosis transmission.

Updated distribution and experimental life-history traits of the recently invasive snail Lissachatina fulica in Havana, Cuba

The giant African snail Lissachatina fulica has been reported invading Cuba since 2014 and is now well established in areas of Havana and several nearby regions. This invasive species is of major concern to health authorities given its role as an important vector of parasites such as Angiostrongylus cantonensis, the causative agent of eosinophilic meningoencephalitis in humans. Here, we update the distribution within Cuba. We also report on our studies of experimental life-history traits to assess the population dynamics and potential for spread of this species in Cuba. The experimental population had a very low probability of dying at first age intervals (Type I survival curve) with a life expectancy of 71 weeks. During our experiment, sexual maturity was reached after 22 weeks (individuals of 70 mm shell length) and eggs were laid regularly (mean batch size: 188 ± 111.79 SD). We failed to detect any deviations from the mortality curve and individuals reached an average of 77.3 mm (shell length) and weighted 57.7 g after one year. Predicted curve models indicate that snails reaching their average lifespan of five years should attain 10-12 cm (shell length) and weight 160 g. The spreading of this invasive and vector snail has been tracked for four years in Cuba showing a steady increase of invaded localities. How fast and how far this species develops in Cuba is unknown but the life history parameters indicated in this paper show that it has a large potential to invade all areas of Cuba quickly unless a systematic abatement strategy is developed.

Changes in Structure and Composition of Two Communities of Rocky Shores Molluscs Exposed to Different Human Impact in Playa Jibacoa, Cuba

Rocky shore molluscs are highly relevant in keeping shore’s dynamics and ecological balance of beaches. The knowledge regarding species distribution patterns is important in understanding how environmental and anthropogenic factors may influence the structure of these communities. This study aimed to explore changes in structure and composition of littoral molluscs in two sites of Playa Jibacoa, Cuba with different human use. Fortyfour species of littoral molluscs were identified. The supralittoral zones exhibited the lowest diversity whereas the interlittoral and sublittoral the highest. These findings point the latter as the most vulnerable zones to human perturbation. Species were more abundant and evenly distributed in the site with less human activity. This effect showed a seasonal pattern since in both sites these variables were more affected in the summer probably because of an increased attendance of tourists to the beach. Species were mostly associated with the type of substrate and the stratum than to any other variable. Significant changes in diversity were observed between seasons with a decrease in summer.