Systematics and geographical distribution of Galba species, a group of cryptic and worldwide freshwater snails.

Cryptic species can present a significant challenge to the application of systematic and biogeographic principles, especially if they are invasive or transmit parasites or pathogens. Detecting cryptic species requires a pluralistic approach in which molecular markers facilitate the detection of coherent taxonomic units that can then be analyzed using various traits (e.g., internal morphology) and crosses. In asexual or self-fertilizing species, the latter criteria are of limited use. We studied a group of cryptic freshwater snails (genus Galba) from the family Lymnaeidae that have invaded almost all continents, reproducing mainly by self-fertilization and transmitting liver flukes to humans and livestock. We aim to clarify the systematics, distribution, and phylogeny of these species with an integrative approach that includes morphology, molecular markers, wide-scale sampling across America, and data retrieved from GenBank (to include Old World samples). Our phylogenetic analysis suggests that the genus Galba originated ca. 22 Myr ago and today comprises six species or species complexes. Four of them show an elongated-shell cryptic phenotype and exhibit wide variation in their genetic diversity, geographic distribution, and invasiveness. The remaining two species have more geographically restricted distributions and exhibit a globose-shell cryptic phenotype, most likely phylogenetically derived from the elongated one. We emphasize that no Galba species should be identified without molecular markers. We also discuss several hypotheses that can explain the origin of cryptic species in Galba, such as convergence and morphological stasis.

A new multiplex PCR assay to distinguish among three cryptic Galba species, intermediate hosts of Fasciola hepatica.

A molecular tool described here allows in one step for specific discrimination among three cryptic freshwater snail species (genus Galba) involved in fasciolosis transmission, a worldwide infectious disease of humans and livestock. The multiplex PCR approach taken targets for each species a distinctive, known microsatellite locus which is amplified using specific primers designed to generate an amplicon of a distinctive size that can be readily separated from the amplicons of the other two species on an agarose gel. In this way, the three Galba species (G. cubensis, G. schirazensis, and G. truncatula) can be differentiated from one another, including even if DNA from all three were present in the same reaction. The accuracy of this new molecular tool was tested and validated by comparing multiplex PCR results with species identification based on sequences at mitochondrial and nuclear markers. This new method is accurate, inexpensive, simple, rapid, and can be adapted to handle large sample sizes. It will be helpful for monitoring invasion of Galba species and for developing strategies to limit the snail species involved in the emergence or re-emergence of fasciolosis.

Seroprevalence of Trypanosoma cruzi Infection in Schoolchildren and in Pregnant Women from an Amazonian Region in Orellana Province, Ecuador.

Chagas disease is a parasitic disease caused by the protozoan parasite Trypanosoma cruzi and about 230,000 persons are estimated to be infected in Ecuador. However, limited studies have been performed in the Amazon region, on the eastern side of the country. We evaluated here the seroprevalence of Trypanosoma cruzi infection in 12 rural villages of the Loreto canton, Orellana Province in schoolchildren aged 5-15 years and in pregnant women. A total of 1,649 blood samples were tested for Trypanosoma cruzi antibodies by enzyme-linked immunosorbent assay and indirect hemaglutination, and discordant samples were tested by indirect immunofluorescence assay. We detected a seroprevalence of anti-Trypanosoma cruzi antibodies of 1.3% in schoolchildren aged 5-15 years, indicating the persistence of a constant and active vectorial transmission in the Loreto County and confirming the need of the implementation of nonconventional vector control. We also observed a seroprevalence of 3.8% in pregnant women, indicating a clear risk of congenital transmission. Further studies should help define this risk more precisely and implement current international guidelines for the diagnosis, treatment, and care of these cases.

Neuroimmunological findings of Angiostrongylus cantonensis meningitis in Ecuadorian patients.

UNLABELLED: Meningitis caused by Angiostrongylus cantonensis has recently been reported in patients resulting from the first outbreaks in subtropical regions of Ecuador. METHOD: Eight young adult patients from the two outbreaks were studied. IgA, IgM, IgG and albumin in cerebrospinal fluid and serum were quantified and plotted in cerebrospinal fluid/serum quotient diagrams (Reibergrams). The anamnesis on the patients included asking about any consumption of raw snails, symptoms and harm caused. RESULTS: Mean eosinophilia of 7.5% and 26% in serum and cerebrospinal fluid respectively was observed, as well as a moderate increase in total proteins. The most frequent pattern of intrathecal synthesis was observed in three classes of immunoglobulins. Intrathecal synthesis of IgM was observed in all cases two weeks after the first symptoms appeared. CONCLUSION: The intrathecal synthesis patterns of eosinophilic meningitis due to Angiostrongylus cantonensis, facilitated by cerebrospinal fluid analysis, were similar to those of previous cases from abroad.

Neuroimmunological findings of Angiostrongylus cantonensis meningitis in ecuadorian patients / Hallazgos neuroinmunologicos en meningitis por Angiostrongylus cantonesis en pacientes ecuatorianos

Meningitis caused by Angiostrongylus cantonensis has recently been reported in patients resulting from the first outbreaks in subtropical regions of Ecuador. METHOD: Eight young adult patients from the two outbreaks were studied. IgA, IgM, IgG and albumin in cerebrospinal fluid and serum were quantified and plotted in cerebrospinal fluid/serum quotient diagrams (Reibergrams). The anamnesis on the patients included asking about any consumption of raw snails, symptoms and harm caused. RESULTS: Mean eosinophilia of 7.5 percent and 26 percent in serum and cerebrospinal fluid respectively was observed, as well as a moderate increase in total proteins. The most frequent pattern of intrathecal synthesis was observed in three classes of immunoglobulins. Intrathecal synthesis of IgM was observed in all cases two weeks after the first symptoms appeared. CONCLUSION: The intrathecal synthesis patterns of eosinophilic meningitis due to Angiostrongylus cantonensis, facilitated by cerebrospinal fluid analysis, were similar to those of previous cases from abroad.

La meningitis provocada por Angiostrongylus cantonensis ha sido reportada recientemente en pacientes procedentes de los primeros brotes reportados en regiones subtropicales de Ecuador. MÉTODO: Ocho adultos jóvenes procedentes de dos brotes fueron estudiados. Se cuantificó IgA, IgM, IgG y albúmina en suero y líquido cefalorraquídeo y fueron colocados en los gráficos de las razones líquido cefalorraquídeo/suero (reibergramas). La anamnesia incluía ingestión de caracoles crudos, los síntomas y los daños provocados. RESULTADOS: Una eosinofílica promedio de 7,5 y 26 por ciento en suero y líquido cefalorraquídeo fue observada al igual que un moderado incremento en las proteínas totales. El patrón de síntesis intratecal predominante fue de tres clases de inmunoglobulinas. La síntesis intratecal de IgM se observó en todos los casos a las dos semanas después del inicio de los síntomas. CONCLUSIÓN: El patrón de síntesis intratecal de la meningitis eosinofílica por Angiostrongylus cantonensis facilitado por el análisis del líquido cefalorraquídeo fue similar a los casos previos reportados fuera del país.