Heavy metal and genetic diversity studies in three populations of Snail (Achatina achatina Linnaeus, 1758) from Southwest, Nigeria / Estudos de heavy metal e diversidade genética em três populações de Snail (Achatina achatina Linnaeus, 1758) do sudoeste da Nigéria

Environmental pollutants may often alter the genetic components of natural populations. In this study, heavy metals and genetic diversity in land snail (Achatina achatina) from three populations of south-western Nigeria were investigated, using the Atomic Absorption Spectrometry and DNA Sequencing technology respectively. Metal analysis revealed that the snails accumulated lead (Pb) and nickel (Ni) in high concentrations in two of the three states, while cadmium (Cd) was the least detected. Editing and alignment of the sequences of all snail accessions generated a range of 384bp to 419 bp. Analysis of Molecular Variance (AMOVA) in all 18 accessions was low at only 16%. The query coverage (QC) ranged between 96% and 100%, with 14 (77.8%) of the 18 accessions showing 100% identity. Pairwise comparison of the accessions studied also showed a high genetic similarity. The unweighted pair group method with arithmetic mean (UPGMA) generated two main clusters. Cluster I was unique and contain one sample (AaOy06) while the other cluster are very closely related and can be further sub-divided into sub-clusters. The similarity index of between the clusters is 0.5357. The close similarity among the accessions may be due to the geographical proximity of the three states. The uniqueness of accession AaOy06 in comparison to other accessions might be due to the negative influence of heavy metal, particularly lead. The determination of evolutionary relationships among snail populations may be useful towards the breeding efforts of the species in Nigeria.

Os poluentes ambientais podem frequentemente alterar os componentes genéticos das populações naturais. Neste estudo, metais pesados e diversidade genética em caramujos terrestres (Achatina achatina) de três populações do sudoeste da Nigéria foram investigados, usando a tecnologia de espectrometria de absorção atômica e sequenciamento de DNA, respectivamente. A análise dos metais revelou que os caramujos acumularam chumbo (Pb) e níquel (Ni) em altas concentrações em dois dos três estados, enquanto o cádmio (Cd) foi o menos detectado. A edição e o alinhamento das sequências de todos os acessos de caramujos geraram uma faixa de 384pb a 419pb. A análise de variância molecular (AMOVA) em todos os 18 acessos foi baixa em apenas 16%. A cobertura da consulta (QC) variou entre 96% e 100%, com 14 (77,8%) dos 18 acessos apresentando 100% de identidade. A comparação pareada dos acessos estudados também mostrou alta similaridade genética. O método de grupo de pares não ponderados com média aritmética (UPGMA) gerou dois clusters principais. O cluster I era único e contém uma amostra (AaOy06), enquanto o outro cluster está intimamente relacionado e pode ser subdividido em subclusters. O índice de similaridade entre os clusters é 0,5357. A grande semelhança entre os acessos pode ser devido à proximidade geográfica dos três estados. A singularidade do acesso AaOy06 em comparação com outros acessos pode ser devido à influência negativa de metais pesados, particularmente chumbo. A determinação das relações evolutivas entre as populações de caramujos pode ser útil para os esforços de reprodução da espécie na Nigéria.

Light Microscopic, Ultrastructure Analysis and Functional Morphology of Cornu aspersum Spermatozoa Contained in the Frozen Hermaphroditic Duct / Análisis de Microscopía de Luz, Ultraestructura y Morfología Funcional de Espermatozoides de Cornu aspersum Contenidos en el Conducto Hermafrodita Congelado

SUMMARY: In this study we describe the functional morphology of Cornu aspersum (Helix aspersa), spermatozoa using light, scanning (SEM) and transmission electron (TEM) microscopies. The studies were performed with sperm located in the frozen hermaphroditic duct. Our results showed that the head presents an elongated conical shape slightly coiled in a corkscrew, with the nucleus partially covered by an acrosome, where an apical vesicle is located at the lateralized apex. This peculiar shape suggests the helical displacement movement of the spermatozoa. The head and the nucleus are slightly larger size compared to those of other gastropod species. The intermediate tract is surrounded by a mitochondrial complex and a glycogen helix. The glycogen helix is coiled helically along the intermediate tract, presenting at least five twists of glycogen helices. The complexity of both the mitochondrial complex and the glycogen helix suggests a high metabolic consumption considering the long period of time until fertilization occurs. Our findings on the detailed characterization of Cornu aspersum spermatozoa, obtained from a frozen hermaphroditic duct can contribute to a better understanding of the functional morphology of sperm and serve as a reference for future studies.

En este estudio describimos la morfología funcional de Cornu aspersum (Helix aspersa), espermatozoides utilizando microscopías de luz, barrido (SEM) y electrónica de transmisión (TEM). Los estudios se realizaron con espermatozoides localizados en el conducto hermafrodita congelado. Nuestros resultados mostraron que la cabeza presenta una forma cónica alargada ligeramente enrollada en un tirabuzón, con el núcleo parcialmente cubierto por un acrosoma, donde se ubica una vesícula apical en el ápice lateralizado. Esta peculiar forma sugiere el movimiento de desplazamiento helicoidal de los espermatozoides. La cabeza y el núcleo son de un tamaño ligeramente mayor en comparación con los de otras especies de gasterópodos. El tracto intermedio está rodeado por un complejo mitocondrial y una hélice de glucógeno. La hélice de glucógeno se enrolla helicoidalmente a lo largo del tracto intermedio, presentando al menos cinco giros de hélices de glucógeno. La complejidad tanto del complejo mitocondrial como de la hélice de glucógeno sugiere un alto consumo metabólico considerando el largo período de tiempo hasta que ocurre la fecundación. Nuestros hallazgos sobre la caracterización detallada de los espermatozoides de Cornu aspersum, obtenidos de un conducto hermafrodita congelado, pueden contribuir a una mejor comprensión de la morfología funcional de los espermatozoides y servir como referencia para futuros estudios.

Considering the role of the assassin snail Anentome helena as a biological control of Bithynia siamensis goniomphalos, the first intermediate host of Opisthorchis viverrini

This study aims to investigate whether the assassin snail Anentome helena may serve as a biological control agent of Bithynia siamensis goniomphalos, the 1st intermediate host of Opisthorchis viverrini. Experiments were carried out in the laboratory, and the results found that A. helena showed the variation and selection of mollusc prey. A. helena can consume B. siamensis goniomphalos, which is remarkable because this snail can compete with other snails and could be used as a biological control. The consumption rate of the predator was compared, and it was found that A. helena prefers to consume Indoplanorbis exustus, followed by Pomacea canaliculata, Melanoides tuberculata, Filopaludina sumatrensis speciosa, Lymnaea sp., and B. siamensis goniomphalos. This is the first report of an experimental study controlling B. siamensis goniomphalos using A. helena. Our data imply that A. helena can control the B. siamensis goniomphalos population with good results, especially in the absence of other snail species.

The introduction of Physa acuta (Gastropoda: Physidae) on Ilha Grande, Southeast Brazil, from initial stages to an established population / A introdução de Physa acuta Draparnaud, 1805 (Gastropoda: Physidae) na Ilha Grande, Sudeste do Brasil, desde os estágios iniciais até uma população estabelecida

Abstract This study presents a four-year follow-up of an introduced population of Physa acuta Draparnaud, 1805, from initial stages to an established population. This introduction occurred on a small impacted stream of Vila do Abraão, the main village of Ilha Grande (Angra dos Reis, Rio de Janeiro, Brazil). The population size increased during the study, and presented a relationship to environmental factors, especially with rainfall. On the initial stages of introduction prevailed the smaller specimens, but on the overall, predominated the intermediate size classes. After less than a year, P. acuta becomes established on this stream and was possibly affecting the other species found on the stream. The information presented here is useful to understand the invasion process of invasive snails, as well as directing conservation efforts.

Resumo Neste estudo é apresentado um acompanhamento de quatro anos de uma população de Physa acuta Draparnaud, 1805, desde os estágios iniciais da introdução até seu pleno estabelecimento. Esta introdução ocorreu em um pequeno riacho impactado da Vila do Abraão, o principal vilarejo da Ilha Grande (Angra dos Reis, Rio de Janeiro, Brasil). A população cresceu durante o estudo, e apresentou uma relação com os fatores ambientais, especialmente a pluviosidade. Nos estágios iniciais de introdução prevaleceram os exemplares menores, contudo no panorama geral, predominaram as classes de tamanho intermediárias. Em menos de um ano de introdução, P. acuta se estabeleceu neste riacho, e possivelmente está afetando as demais espécies encontradas no rio. A informação apresentada aqui é importante para a compreensão do processo de invasão de moluscos invasores no Brasil, assim como no direcionamento de esforços de conservação.

Identification of terrestrial gastropods families found in district Swat, Pakistan / Identificação de famílias de gastropódeos terrestres encontradas no distrito Swat, Paquistão

Abstract Very little is known about the malacofauna in district Swat of Khyber Pakhtunkhwa province, situated in the Northern part of Pakistan. The Swat valley possesses a variety of suitable environmental conditions, providing different types of habitats for both flora and fauna. Taken into consideration these points, the present study was conducted to explore the terrestrial snails diversity in agricultural and non-agricultural fields in the lower Swat valley. A total of 417 shells were collected from three sites: Kokarai, Kanju Township, and Deolai. Based on conchological features, three families: Bradybaenidae, Hygromiidae, and Zonitidae were identified using different terrestrial snail keys. In Kokarai and Deolai, shells of members of all the above-mentioned families were found from agricultural fields. In Kanju Township, shells of members of the family Bradybaenidae and Zonitidae were found. From these findings, it was concluded that district Swat possesses a significant malacofauna which was unexplored before and aided more to the existing literature on malacofauna. It also supports the idea that the agroecosystem is rich in species diversity. Further in-depth and extensive study is recommended to be carried out for a detailed taxonomy of the described terrestrial gastropod families.

Resumo Muito pouco se sabe sobre a malacofauna no distrito de Swat, na província de Khyber Pakhtunkhwa, situada na parte norte do Paquistão. O vale do Swat possui uma variedade de condições ambientais adequadas, proporcionando diferentes tipos de habitats para a flora e a fauna. Levando em consideração esses pontos, o presente estudo foi conduzido para explorar a diversidade dos caracóis terrestres em campos agrícolas e não agrícolas no vale inferior de Swat. Um total de 417 conchas foram coletadas em três locais: Kokarai, Kanju Township e Deolai. Com base em características concológicas, três famílias: Bradybaenidae, Hygromiidae e Zonitidae foram identificadas usando diferentes chaves de caramujos terrestres. Em Kokarai e Deolai, conchas de membros de todas as famílias mencionadas acima foram encontradas em campos agrícolas. No município de Kanju, foram encontradas conchas de membros da família Bradybaenidae e Zonitidae. A partir dessas constatações, concluiu-se que o distrito de Swat possui uma malacofauna significativa que antes era inexplorada e ajudava mais a literatura existente sobre a malacofauna. Também apoia a ideia de que o agroecossistema é rico em diversidade de espécies. Recomenda-se a realização de um estudo mais aprofundado e extenso para uma taxonomia detalhada das famílias de gastrópodes terrestres descritas.

Characterization of the species of genus Physa on the basis of typological species concept from Central Punjab / Caracterização das espécies do gênero Physa com base no conceito tipológico de espécie do Punjab Central

Abstract Physids belong to Class Gastropoda; Phylum Mollusca have important position in food web and act as bio indicators, pests and intermediate host. Being resistant these are called cockroaches of malacology. Physid snails were collected from different water bodies of Faisalabad (Punjab) and were identified up to species using morphological markers. The morphometry of the specimens was carried out with the help of a digital Vernier caliper in millimeters (mm) using linear measurement of shell characters. Linear regression analysis of the AL/SW ratio vs AL and SL/SW ratio vs AL indicated that allometric growth exists only in Physa acuta when compared with P.gyrina and P. fontinalis. This study will lead to assess the status of the Physid species in Central Punjab. The Principal component analysis shows that the Component 1 (Shell Length) and component 2 (Shell Width) are the most prolific components and nearly 80 percent of the identification. The distance between P. acuta and P. fontinalis is 5.4699, P. acuta and P. gyrina is 7.6411, P. fontinalis and P. gyrina is 16.6080 showing that P. acuta resembles with P. fontinalis, and both these specimens donot resemble with P. gyrina. P.acuta is an invasive species and shows bioactivity making it a potent candidate for bioactive substances.

Resumo Os físidos pertencem à classe Gastropoda; o filo Mollusca possui importante posição na teia alimentar e atua como bioindicador, praga e hospedeiro intermediário. Por serem resistentes, são chamadas baratas de malacologia. Os caramujos físidos foram coletados em diferentes corpos d'água de Faisalabad (Punjab) e identificados até as espécies por meio de marcadores morfológicos. A morfometria dos corpos de prova foi realizada com auxílio de paquímetro digital Vernier em milímetros (mm) por meio de medida linear dos caracteres da casca. A análise de regressão linear da razão AL / SW vs. AL e razão SL / SW vs. AL indicou que o crescimento alométrico existe apenas em Physa acuta quando comparado com P. gyrina e P. fontinalis. Este estudo levará a avaliar a situação das espécies de físido no Punjab Central. A análise do componente principal mostra que o componente 1 (comprimento da casca) e o componente 2 (largura da casca) são os componentes mais prolíficos e quase 80% da identificação. A distância entre P. acuta e P. fontinalis é 5,4699, P. acuta e P. gyrina é 7,6411, P. fontinalis e P. gyrina é 16,6080, mostrando que P. acuta se assemelha a P. fontinalis, e ambos os espécimes não se parecem com P. gyrina. P. acuta é uma espécie invasora e apresenta bioatividade, tornando-se uma candidata potente para substâncias bioativas.

Identification of terrestrial gastropods families found in district Swat, Pakistan / Identificação de famílias de gastropódeos terrestres encontradas no distrito Swat, Paquistão

Very little is known about the malacofauna in district Swat of Khyber Pakhtunkhwa province, situated in the Northern part of Pakistan. The Swat valley possesses a variety of suitable environmental conditions, providing different types of habitats for both flora and fauna. Taken into consideration these points, the present study was conducted to explore the terrestrial snails diversity in agricultural and non-agricultural fields in the lower Swat valley. A total of 417 shells were collected from three sites: Kokarai, Kanju Township, and Deolai. Based on conchological features, three families: Bradybaenidae, Hygromiidae, and Zonitidae were identified using different terrestrial snail keys. In Kokarai and Deolai, shells of members of all the above-mentioned families were found from agricultural fields. In Kanju Township, shells of members of the family Bradybaenidae and Zonitidae were found. From these findings, it was concluded that district Swat possesses a significant malacofauna which was unexplored before and aided more to the existing literature on malacofauna. It also supports the idea that the agroecosystem is rich in species diversity. Further in-depth and extensive study is recommended to be carried out for a detailed taxonomy of the described terrestrial gastropod families.

Muito pouco se sabe sobre a malacofauna no distrito de Swat, na província de Khyber Pakhtunkhwa, situada na parte norte do Paquistão. O vale do Swat possui uma variedade de condições ambientais adequadas, proporcionando diferentes tipos de habitats para a flora e a fauna. Levando em consideração esses pontos, o presente estudo foi conduzido para explorar a diversidade dos caracóis terrestres em campos agrícolas e não agrícolas no vale inferior de Swat. Um total de 417 conchas foram coletadas em três locais: Kokarai, Kanju Township e Deolai. Com base em características concológicas, três famílias: Bradybaenidae, Hygromiidae e Zonitidae foram identificadas usando diferentes chaves de caramujos terrestres. Em Kokarai e Deolai, conchas de membros de todas as famílias mencionadas acima foram encontradas em campos agrícolas. No município de Kanju, foram encontradas conchas de membros da família Bradybaenidae e Zonitidae. A partir dessas constatações, concluiu-se que o distrito de Swat possui uma malacofauna significativa que antes era inexplorada e ajudava mais a literatura existente sobre a malacofauna. Também apoia a ideia de que o agroecossistema é rico em diversidade de espécies. Recomenda-se a realização de um estudo mais aprofundado e extenso para uma taxonomia detalhada das famílias de gastrópodes terrestres descritas.

Reproducción y limitaciones de pesca recomendadas para el caracol marino Hexaplex princeps (Neogastropoda: Muricidae) en Guerrero, México / Reproduction and recommended fishing limitations for the marine snail Hexaplex princeps (Neogastropoda: Muricidae) in Guerrero, Mexico

Abstract Introduction: The snail Hexaplex princeps is the most important gastropod in the fishery of Guerrero, but capture is not legally regulated for lack of enough studies about its reproduction, growth and other fishing aspects. Objective: To assess fishery data for H. princeps in Guerrero. Methods: From October 2016 to December 2017, we analyzed histological samples of the gonads from 6 to 13 individuals per month. We also collected data on pre-reproductive organisms captured in Costa Chica (2013 and 2014), Costa Grande (2017) and Acapulco (2019 and 2020). Results: Both sexes have five stages of gonadal development; most reproductive activity was from December to July, related to sea surface temperatures of 26 to 28 °C. The LC M in females was 94.1 mm (males: 86.1 mm). There was a high percentage of juvenile organisms in the catches (88.6 %). Conclusions: To let these snails reproduce at least once, we recommend a fishing ban from December to July, and that the minimum size of commercial capture be set at 94.1 mm.

Resumen Introducción: El caracol Hexaplex princeps es el gasterópodo más importante en la pesquería de Guerrero, pero su captura no está regulada legalmente por falta de suficientes estudios sobre su reproducción, crecimiento y otros aspectos de la pesca. Objetivo: Evaluar los datos de pesca de H. princeps en Guerrero. Métodos: De octubre 2016 a diciembre 2017, analizamos muestras histológicas de las gónadas de 6 a 13 individuos por mes. También recolectamos datos sobre organismos pre-reproductivos capturados en Costa Chica (2013 y 2014), Costa Grande (2017) y Acapulco (2019 y 2020). Resultados: Ambos sexos tienen cinco etapas de desarrollo gonadal; la mayor actividad reproductiva fue de diciembre a julio, relacionada con las temperaturas superficiales del mar, que se encuentran entre 26 y 28 °C. El LC M en hembras fue de 94.1 mm (machos: 86.1 mm). Hubo un alto porcentaje de organismos juveniles en las capturas (88.6 %). Conclusiones: Para que estos caracoles se reproduzcan al menos una vez, se recomienda una veda de diciembre a julio y que la talla mínima de captura comercial se fije en 94.1 mm.

Distribución geográfica de la familia de caracoles terrestres Spiraxidae (Gastropoda: Pulmonata) en México / Geographic distribution of the land snail family Spiraxidae (Gastropoda: Pulmonata) in Mexico

Resumen Introducción: Spiraxidae es la familia de gasterópodos terrestres más diversa de México con una distribución principalmente neotropical. Sin embargo, la influencia de las condiciones ambientales de esta región en su distribución aún es poco conocida. Objetivo: Determinar las afinidades zoogeográficas y la influencia de factores ambientales en la distribución de Spiraxidae en México. Métodos: Compilamos registros de distribución de museos y usamos modelos para establecer áreas con composición de especies, concentración de especies, afinidades y relaciones con variables ambientales similares. Resultados: Encontramos 231 especies y subespecies, 96 en el estado de Veracruz y 74 en la Sierra Madre Oriental. La principal afinidad zoogeográfica fue neotropical. El bosque mesófilo de montaña tuvo la mayor cantidad de especies y subespecies (93). Tres de los grupos zonales tienen una composición particular de especies y el 67 % de las especies son especialistas de hábitat. La presencia de especies sigue un gradiente ambiental, con la cubierta de árboles de hoja perenne de hoja ancha y la precipitación media anual como variables determinantes. Las especies del norte tuvieron mayor tolerancia a la aridez y menor cobertura de hojas. Conclusiones: Spiraxidae tiene su mayor diversidad en los estados del Sur de México; sin embargo, la zona nororiental tiene más registros de especies. Estos caracoles se encuentran principalmente en bosques mesófilos de montaña y bosques tropicales siempre verdes. Las especies del norte de México tuvieron una mayor tolerancia a los sitios con poca lluvia y menos cobertura de árboles de hoja perenne de hoja ancha que las especies del sur.

Abstract Introduction: Spiraxidae is the most diverse family of terrestrial gastropods in Mexico with a mainly neotropical distribution. However, the influence of environmental conditions in this region on its distribution is still poorly known. Objective: To determine zoogeographic affinities and the influence of environmental factors on the distribution of Spiraxidae in Mexico. Methods: We compiled museum distribution records and used models to establish areas with similar species composition, species concentration, affinities and relationship with environmental variables. Results: We found 231 species and subspecies, 96 in Veracruz state and 74 in Sierra Madre Oriental. The main zoogeographic affinity was neotropical. Mountain mesophyll forest had the most species and subspecies (93). Three of zone groups have a particular species composition and 67 % of the species are habitat specialists. Species presence follows an environmental gradient, with broadleaf evergreen tree cover and average annual precipitation as determining variables. Northern species had greater tolerance to aridity and reduced leaf cover. Conclusions: Spiraxidae has its greatest diversity in the Southern states of Mexico; however, the Northeastern zone has more species records. These snails mostly occur in mesophyll mountain forest and tropical evergreen forest. Species from Northern Mexico had greater tolerance to sites with low rainfall and less broadleaf evergreen tree cover than Southern species.

Prevalencia de Fasciola hepatica y Paramphistomidae en bovinos de doble propósito en una hacienda del trópico bajo andino colombiano / Prevalence of Fasciola hepatica and Paramphistomidae in dual purpose cattle in a farm in the Colombian low Andean tropic

RESUMEN En muchos países la fasciolosis y la paramfistomosis representan un grave problema para la salud del sector pecuario. En Colombia hay registros de ambas distomatosis en bovinos, la mayoría en el trópico alto andino, las cuales generan pérdidas econômicas anuales cercanas a 40 000 000 000 COP. El objetivo de esta investigación fue determinar la prevalencia de fasciolosis y paramfistomosis en vacunos de la hacienda La Candelaria, Caucasia (Colombia), y la presencia de caracoles hospederos intermediarios. Para cumplirlo, se realizó un estudio descriptivo de corte transversal con muestreo no probabilístico por conveniencia. Se recolectaron heces de los animales y se hizo el diagnóstico mediante la técnica modificada de Dennis. Se establecieron las prevalencias de los digeneos de acuerdo con el sexo, peso, edad y raza. Se recolectaron caracoles dulciacuícolas en la zona estudiada y se identificaron por morfologia. Se analizaron 466 muestras fecales de 178 bovinos, de las razas Cebú (Bos indicus), BON (blanco orejinegro) y del cruce entre ellas. Se diagnosticaron F. hepatica y Paramphistomidae con prevalencias del 2,2% y 30,9%, respectivamente. En el 1,1% de los vacunos se diagnosticó coinfección. Ambas trematodosis prevalecieron en las hembras (p = 0,03). Se identificaron moluscos dulciacuícolas Ampullariidae, Physidae y Planorbidae sin estadios larvarios de digeneos. Se concluyó que los bovinos de doble propósito de la hacienda La Candelaria están expuestos a F. hepatica y Paramphistomidae, y, probablemente, se infectan en los predios de la hacienda. Paramphistomidae es más prevalente que F. hepatica, lo cual concuerda con lo descrito en algunos estudios realizados en hatos del trópico alto andino colombiano. Paramphistomidae se encontró en todos los grupos etarios.

ABSTRACT Fasciolosis and paramphistomosis are a major health problem for the livestock economy worldwide. In Colombia, both distomatosis are reported in cattle, particularly in high Andean tropics, with annual economic losses close to COP 40 billion. The goal of this study was to determine the prevalence of fasciolosis and paramphistomosis in cattle from La Candelaria farm, Caucasia (Colombia), and the presence of intermediate host snails. A descriptive cross-sectional study was carried out with non-probability convenience sampling. Stool samples were collected from the animals and the diagnosis was made using the modified Dennis technique. Digenea prevalence were determined according to sex, weight, age, and race. Freshwater snails were collected in the studied area and were identified by morphology. 400 and 66 fecal samples from 178 bovines of the Zebu (Bos indicus), BON (white-eared white) breeds and the cross between them were analyzed. Fasciola hepatica and Paramphistomidae were diagnosed with a prevalence of 2,2% and 30,9%, respectively. Coinfection was diagnosed in 1,1% of the cattle. Both trematodosis were most frequent in females (p = 0,03). Freshwater molluscs Ampullariidae, Physidae and Planorbidae without digenea larval stages were identified. It was concluded that dual-purpose cattle from La Candelaria farm are exposed to F. hepatica and Paramphistomidae and are probably infected on the farm grounds. Paramphistomidae was more prevalent than F. hepatica, which agrees with other studies in herds from the Colombian high Andean tropics. Paramphistomidae was found in all age groups.

Molluscicidal activity of the secondary metabolites from Streptomyces nigrogriseolus XD 2-7 against Oncomelania hupensis and its preliminary mechanisms of molluscicidal actions / 中国血吸虫病防治杂志

OBJECTIVE@#To evaluate the storage stability of metabolites from actinomycetes Streptomyces nigrogriseolus XD 2-7 and the mollcuscicidal activity against Oncomelania hupensis in the laboratory, and to preliminarily explore the mechanisms of the molluscicidal activity.@*METHODS@#The fermentation supernatant of S. nigrogriseolus XD 2-7 was prepared and stored at -20, 4 °C and 28 °C without light for 10 d; then, the molluscicidal effect was tested against O. hupensis following immersion for 72 h. The fermentation supernatant was boiled in a 100 °C water bath for 30 min and recovered to room temperature, and then the molluscicidal effect was tested against O. hupensis following immersion for 72 h. The pH values of the fermentation supernatant were adjusted to 4.0, 6.0 and 9.0 with concentrated hydrochloric acid and sodium hydroxide, and the fermentation supernatant was stilled at room temperature for 12 h, with its pH adjusted to 7.0; then, the molluscicidal effect was tested against O. hupensis following immersion for 72 h. The fermentation product of S. nigrogriseolus XD 2-7was isolated and purified four times with macroporous resin, silica gel and octadecylsilane bonded silica gel. The final products were prepared into solutions at concentrations of 10.00, 5.00, 2.50, 1.25 mg/L and 0.63 mg/L, and the molluscicidal effect of the final productswas tested against O. hupensis following immersion for 72 h, while dechlorination water served as blank controls, and 0.10 mg/L niclosamide served as positive control. The adenosine triphosphate (ATP) and adenosine diphosphate (ADP) levels were measured in in O. hupensis soft tissues using high performance liquid chromatography (HPLC) following exposure to the final purified fermentation products of S. nigrogriseolus XD 2-7.@*RESULTS@#After the fermentation supernatant of S. nigrogriseolus XD 2-7 was placed at -20, 4 °C and 28 °C without light for 10 d, immersion in the stock solution and solutions at 10- and 50-fold dilutions for 72 h resulted in a 100% (30/30) O. hupensis mortality. Following boiling at 100 °C for 30 min, immersion in the stock solution and solutions at 10- and 50-fold dilutions for 72 h resulted in a 100.00% (30/30) O. hupensis mortality. Following storage at pH values of 4.0 and 6.0 for 12 h, immersion in the fermentation supernatant of S. nigrogriseolus XD 2-7 for 72 h resulted in a 100.00% (30/30) O. hupensis mortality, and following storage at a pH value of 9.0 for 12 h, immersion in the fermentation supernatant of S. nigrogriseolus XD 2-7 for 72 h resulted in a 33.33% (10/30) O. hupensis mortality (χ2 = 30.000, P < 0.05). The minimum concentration of the final purified fermentation products of S. nigrogriseolus XD 2-7 was 1.25 mg/L for achieving a 100% (30/30) O. hupensis mortality. The ATP level was significantly lower in O. hupensis soft tissues exposed to 0.10 mg/L and 1.00 mg/L of the final purified fermentation products of S. nigrogriseolus XD 2-7 than in controls (F = 7.274, P < 0.05), while no significant difference was detected in the ADP level between the treatment group and controls (F = 2.485, P > 0.05).@*CONCLUSIONS@#The active mollcuscicidal ingredients of the S. nigrogriseolus XD 2-7 metabolites are maintained stably at -20, 4 °C and 28 °C for 10 d, and are heat and acid resistant but not alkali resistant. The metabolites from S. nigrogriseolus XD 2-7 may cause energy metabolism disorders in O. hupensis, leading to O. hupensis death.

Sharing the WHO guideline on control and elimination of human schistosomiasis to achieve the goal of schistosomiasis elimination in China / 中国血吸虫病防治杂志

Currently, the national schistosomiasis control program of China is moving from transmission interruption to elimination, and there are multiple challenges during the stage moving towards the progression of schistosomiasis elimination, including a high difficulty in shrinking snail-infested areas, unstable achievements for infectious source control, imperfect surveillance system and a reduction in schistosomiasis control and administration. Based on the core suggestions proposed in the 2022 WHO guideline on control and elimination of human schistosomiasis, recommendations on schistosomiasis surveillance system building, development of novel diagnostics, adjustment of the schistosomiasis control strategy and maintaining and improvements of the schistosomiasis control capability are proposed for the national schistosomiasis control program of China in the new era according to the actual status of schistosomiasis control in China. Formulation of the national schistosomiasis control strategy and goal from One Health perspective, verification of transmission interruption and elimination of schistosomiasis, precision implementation of schistosomiasis control interventions with adaptations to local circumstances, development and application of highly sensitive and specific diagnostics are recommended for elimination of schistosomiasis in China. In addition, the implementation of the 2022 WHO guideline on control and elimination of human schistosomiasis may guide the elimination of schistosomiasis in China.

Angiostrongylus cantonensis en Achatina fulica en la provincia del Napo, Ecuador y el riesgo incrementado de angiostrongiliasis / Angiostrongylus cantonensis in Achatina fulica in Napo province, Ecuador and the increased risk of angiostrongyliasis

Introducción: Angiostrongylus cantonensis es reconocido como uno de los principales patógenos causantes de la meningoencefalitis eosinofílica, fue identificado en Ecuador por primera vez en 2008. Métodos: se recolectaron 1476 ejemplares de Achatina fulica con el método de captura por unidad de esfuerzo durante 30 minutos, en 3 cantones de la provincia del Napo, con el fin de establecer la prevalencia de infección por A. cantonensis Resultados: el porcentaje total de caracoles infectados fue de 46,5% (687/1476). Conclusiones: Los resultados revelan una amplia distribución de A. fulica infectado con A. cantonensis, lo que, sumado a la gran cantidad de hospederos definitivos presentes, indica que un número considerable de personas tiene riesgo de adquirir angiostrongiliasis. Se necesita intervenciones educativas comunitaria orientadas a formación sanitaria, recalcando el riesgo de adquirir la infección parasitaria, principalmente por el consumo de A. fulica, crudos y/o con cocción inadecuada, principal forma de contagio. Además, se recomienda vigilancia rigurosa y control de los hospedadores involucrados, saneamiento ambiental, haciendo insistencia en factores relacionados con los hábitos biológico del caracol gigante africano, entre ello alimentos (vegetales), suelos y derivados del caracol de uso artesanal; para prevenir la aparición de casos esporádicos y de brotes de la enfermedad(AU)

Introduction: Angiostrongylus cantonensis is recognized as one of the main pathogens that cause eosinophilic meningoencephalitis, it was identified in Ecuador for the first time in 2008. Methods: 1476 specimens of Achatina fulica were collected using the capture method per unit of effort for 30 minutes, in 3 cantons of the Napo province, in order to establish the prevalence of infection by A. cantonensis Results: the total percentage of infected snails was 46.5% (687/1476). Conclusions: The results reveal a wide distribution of A. fulica infected with A. cantonensis, which, added to the large number of definitive hosts present, indicates that a considerable number of people are at risk of acquiring angiostrongyliasis. Community educational interventions aimed at health training are needed, emphasizing the risk of acquiring parasitic infection, mainly due to the consumption of A. fulica, raw and/or inadequately cooked, the main form of contagion. In addition, rigorous surveillance and control of the hosts involved, environmental sanitation, insisting on factors related to the biological habits of the giant African snail, including food (vegetables), soil and snail derivatives for artisanal use; to prevent the appearance of sporadic cases and outbreaks of the disease(AU)

Evaluation of the reproductive profile of Subulina octona (Gastropoda, Subulinidae) experimentally infected by Paratanaisia bragai (Digenea, Eucotylidae) / Avaliação do perfil reprodutivo de Subulina octona (Gastropoda, Subulinidae) infectada experimentalmente por Paratanaisia bragai (Digenea, Eucotylidae)

Abstract Snails infected by trematodes may increase or decrease their reproductive activity in response to the presence of infection. Our aim was to verify the reproductive alterations in Subulina octona after infection by Paratanaisia bragai. The infected snails were individually exposed for 24 hours to 20 parasite eggs and four groups were formed (10, 20, 30 and 40 d.p.i.- days after infection), along with control groups. Every 10 days, the number of eggs in the reproductive tract, number of eggs hatched, galactogen content and histopathological changes were evaluated. The reproductive in the control and infected snails presented an alternating pattern, where periods of high production of eggs and newly hatched were followed by periods of low production. However, in relation to the amount of galactogen, both control and infected groups followed the same pattern of variation. In the histology, we observed the presence of male and female gametes with marked reduction in the number of oocytes. The results indicate that the intra-snail development of the parasite affects the reproductive biology of the host.

Resumo Moluscos infectados por trematódeos podem aumentar ou diminuir sua atividade reprodutiva em resposta à presença da infecção. Nosso objetivo foi verificar as alterações reprodutivas de Subulina octona após a infecção por Paratanaisia bragai. Os moluscos infectados foram individualmente expostos durante 24 horas a 20 ovos do parasito e quatro grupos foram formados (10, 20, 30 e 40 d.p.i. - dias pós infecção), com respectivos grupos controle. A cada 10 dias, o número de ovos no trato reprodutivo, o número de ovos eclodidos, o conteúdo de galactogênio e alterações histopatológicas eram avaliadas. O padrão reprodutivo nos moluscos controle e infectados evidenciou um comportamento alternante, nos quais períodos de alta produção de ovos e filhotes foram seguidos por períodos de baixa produção. No entanto, em relação ao conteúdo de galactogênio, moluscos controle e infectados seguiram o mesmo padrão de variação. Na histologia, observamos a presença de gametas masculinos e femininos com acentuada redução no número de óocitos. Os resultados indicam que o desenvolvimento intramolusco do parasito afeta a biologia reprodutiva do hospedeiro.

A preliminary study on the distribution of breeding sites of BIOMPHALARIA GLABRATA in the municipality of peri mirim, a low endemicity area for schistosomiasis in northeast Brazil

Information on areas colonized by snails that transmit Schistosoma mansoni is essential for planning schistosomiasis control measures. Therefore, the purpose of this study was to map the natural breeding sites of Biomphalaria spp. in the municipality of Peri Mirim, Maranhão, Brazil. The snails were manually collected and the breeding sites were geo-referenced (seven in the urban area and five in flooded fields), from November 2017 to March 2018. In the laboratory, the snails were examined for the presence of larval stages of S. mansoni identified by morphology and internal anatomy analysis. While no snails were found in the urban area, sixteen B. glabrata were collected in the flooded fields. No S. mansoni or other trematode infections were detected. Wild rodents, most likely Holochilus sciureus that could act as S. mansoni reservoirs, were also found in the flooded fields. These data indicate possible risk areas for further outbreaks of schistosomiasis transmission in the municipality of Peri Mirim.

Evaluation of antibiotic resistance of Enterobacteriaceae isolated from edible snails

Aims@#Food safety and drug resistance in bacteria are both important issues globally. Consumption of escargot represents possible food safety problem especially when contaminated with an indicator and multi-drug resistant bacteria. Hence, this study aimed to identify and evaluate susceptibility of Enterobacteriaceae isolated from edible snails Archachatina marginata to antibiotics.@*Methodology and results@# A total of 60 edible snails, A. marginata were purchased from local markets in three states of Nigeria. The edible snails were starved for three days and Enterobacteriaceae were isolated using microbiological procedures. Bacteria was identified by sequencing its partial 16S rRNA, while susceptibility of the bacteria to antibiotic was determined by disc diffusion method. Enterobacteriaceae obtained were Klebsiella (18), Escherichia (16), Citrobacter (10), Salmonella (7) and Enterobacter (5) species. Out of the 56 isolates obtained, 21 (37.5%) were resistant to amoxicillin and amoxicillin/clavulanic acid, 9 (16.07%) were resistant to tetracycline and 4 (7.14%) were resistant to co-trimoxazole. @*Conclusion, significance and impact of study@#The number of isolates which show resistant to different antibiotic classes was small. However, coliform bacteria (Escherichia coli, Klebsiella pneumoniae, Citrobacter freundii, and Enterobacter cloacae) isolated from edible snails represent a huge food safety risk to the consumers of edible snails. Hence, high hygienic practices are required for the consumers of edible snails to prevent infection with pathogenic bacteria.

New Insights into the Gametogenesis of Biomphalaria glabrata (Mollusca, Gastropoda, Pulmonata): Implications for Histopathological Assessment

Abstract The reproductive system has a fundamental role in population dynamics and several reproduction strategies have been shaped by the environment over time. Many environmental pressures are generated by releasing pollutants, as endocrine disruptors, that can affect the reproductive system of individuals, among them invertebrates. The freshwater snails Biomphalaria spp. are used as biomonitor in several ecotoxicological studies; however, there are few studies about gametogenesis and morphology of reproductive snail cells, which could be used as a new biomarker. In this sense, the current study aims to characterize Biomphalaria glabrata gametogenesis, bringing new histomorphometric parameters for germinative cells. Results showed that the hermaphrodite tissue is formed by several acini with simple pavement epithelium with germinative and somatic cells. Oogenesis was classified into five developmental stages (OI to OV) according to diameter, nucleus area, total area, and follicular cell development, and then classified into previtellogenic and vitellogenic oocytes. The spermatogenesis was classified into spermatogonia (Spg), spermatocytes (Spc) and spermatids that were subdivided into five stages (Spt I to Spt V) according to cytoplasm losing, and nucleus spiralization along with Sertoli cells development. Thus, the present study highlights the gametogenesis of B. glabrata with new histomorphometric parameters, which can be an important tool for ecotoxicological and molluscicidal developmental further studies.

Estado actual de Melongena melongena (Mollusca: Gastropoda) en la bahía de Cispatá, Caribe Colombiano / Current status of Melongena melongena(Mollusca: Gastropoda) in Cispatá Bay, Colombian Caribbean

RESUMEN Objetivo. Evaluar el estado actual de Melongena melongena en la bahía de Cispatá, Caribe Colombiano a través de los aspectos poblacionales de la especie. Materiales y métodos. Se establecieron tres sectores de muestreo, conforme con la zonificación de los manglares en la bahía. Para la recolección del material biológico se ubicó un transecto lineal de 4 x 20 m perpendicular al área del manglar con dos replicas a una distancia de 50 m. Para la determinación del sexo, se tomó una submuestra de 10 individuos con tallas superiores a la estimada para la madurez sexual de la especie. A las conchas se les midió la longitud total, con el fin de diferenciar las tallas de hembras y machos. En cada sector, la temperatura del agua y salinidad fueron registradas in situ, empleando un medidor multiparámetro Extech EC170, mientras la trasparencia del agua se calculó mediante el disco Secchi. Resultados. Se registraron un total de 1.149 individuos de M. melongena, obteniendo la mayor abundancia el sector Caño Salado (522), seguido de Las Cagás (458) y finalmente Amaya (169). El 63% de los individuos se encontraron en un intervalo de talla entre 41-61 mm. La proporción sexual fue 1:1.2 (H:M). Las tallas registradas en hembras fueron de 55 a 92 mm y en machos de 54 a 77 mm. Conclusiones. M. melongena en la bahía de Cispatá está presentando signos evidentes de recuperación en la última década, debido a que la mayoría de los individuos registrados han alcanzado la talla media de madurez sexual.

ABSTRACT Objective. Evaluate the current status of Melongena melongena in Cispata Bay, Colombian Caribbean through the population aspects of the species. Materials and methods. Three sampling sectors were established, according to the zoning of the mangrove in the bay. For the collection of the biological material a linear transect of 4 x 20 m was located perpendicular to the area of the mangrove with two replicas at a distance of 50 m. For the determination of sex, a subsample of 10 individuals with sizes greater than that estimated for the sexual maturity of the species was taken. The shells were measured in total length, in order to differentiate the sizes of females and males. In each sector, the water temperature and salinity were measured in situ using an Extech EC170 multiparameter while water transparency is calculated using the Secchi disk. Results. A total of 1,149 individuals of M. melongena were recorded, obtaining the highest abundance in the Caño Salado sector (522), followed by Las Cagás (458) and finally Amaya (169). 63% of the individuals were in a size range between 41-61 mm. The sex ratio was 1:1.2 (H:M). The sizes recorded in females were from 55 to 92 mm and in males from 54 to 77 mm. Conclusions. M. melongena in Cispatá Bay is showing evident signs of recovery in the last decade, because most of the registered individuals have reached the average size of sexual maturity.

Particularidades de la meningoencefalitis eosinofílica en la era del caracol gigante africano / Particular features of eosinophilic meningoencephalitis in the age of the giant African snail

Introducción: la meningoencefalitis eosinofílica es una enfermedad inflamatoria infecciosa reportada en Cuba desde la década de los ochenta del siglo pasado y actualmente extendida al continente americano. Es producida por el parásito Angiostrongylus cantonensis. Objetivo: determinar si existen diferencias entre los pacientes que sufrieron meningoencefalitis eosinofílica antes y después de la introducción del caracol gigante africano. Métodos: se estudiaron un total de 19 muestras de líquido cefalorraquídeo y suero tomadas simultáneamente a cada paciente diagnosticados con meningoencefalitis eosinofílica, perteneciente a la seroraquioteca del Laboratorio Central del Líquido Cefalorraquídeo (LABCEL). Para la determinación de las proteínas albúmina e IgG se empleó como método de laboratorio la inmunodifusión radial. Resultados: el 14 por ciento de los pacientes fueron adultos antes de la aparición de este molusco, en contraste con el momento actual, donde el 50 por ciento son pacientes con edades superiores a 18 años. El porcentaje de síntesis de IgG intratecal media fue mayor en los enfermos actuales, aunque no de manera significativa. Conclusiones: . existen diferencias antes y después de la aparición del caracol gigante africano dado por la respuesta de síntesis intratecal en los pacientes asociados con el molusco que denota una mayor agresividad del parásito. La edad promedio mayor de los enfermos confirma que estos son los que más manipulan y dispersan el molusco(AU)

Introduction: eosinophilic meningoencephalitis is an infectious inflammatory disease reported in Cuba since the 1980s and currently extended to the American continent. This condition is caused by the parasite Angiostrongylus cantonensis. Objective: determine whether there are differences between the patients suffering from eosinophilic meningoencephalitis before and after the introduction of the giant African snail. Methods: a study was conducted of a total 19 cerebrospinal fluid and serum samples taken simultaneously from each of the patients diagnosed with eosinophilic meningoencephalitis and kept at the sample collection of the Central Cerebrospinal Fluid Laboratory (LABCEL). Radial immunodiffusion was the laboratory method used for determination of the proteins albumin and IgG. Results: of the patients studied, 14 percent were adults before the appearance of this mollusc, in contrast with the present moment, when 50 percent are patients aged over 18 years. The percentage of mean intrathecal synthesis of IgG was higher in the current sufferers, though not significantly. Conclusions: there are differences before and after the appearance of the giant African snail, given the intrathecal synthesis response of patients associated to the mollusc, which denotes greater aggressiveness by the parasite. The higher mean age of sufferers confirms that these are the ones who most often handle and disperse the mollusc(AU)