Evaluation of terrestrial gastropods as possible intermediate hosts of Gurltia paralysans in southern Chile / Avaliação de gastrópodes terrestres como possíveis hospedeiros intermediários de Gurltia paralysans no sul do Chile

Abstract Gurltia paralysans is the causal agent of gurltiosis in domestic cats in South America. Although the life cycle of G. paralysans is unknown, it is thought that gastropods could act as intermediate hosts (IHs), as is the case for several nematodes in the Angiostrongylidae family. The aim of this study was to search for G. paralysans larvae in terrestrial gastropods and determine their role in the life cycle of this nematode species. Terrestrial gastropod samples (n=835) were collected in Punucapa, Valdivia, southern Chile, where cases of gurltiosis had been reported before. The samples included species from the families Arionidae, Limacidae, Helicidae and Milacidae. All gastropods were subjected to enzymatic digestion to isolate G. paralysans larvae. Ten percent of the gastropod samples were analyzed using seminested PCR targeting the 28S rRNA gene, while 2.6% were analyzed by histopathological examination. The results indicated the absence of G. paralysans when using any of the three methods. In conclusion, further studies are needed to evaluate specific species of aquatic or native gastropods acting as possible IHs (in this geographic location).

Resumo Gurltia paralysans é o agente etiológico da gurltiose em gatos domésticos na América do Sul. Embora o ciclo biologico de G. paralysans seja desconhecido, provavelmente é indireto com gastrópodes atuando como hospedeiros intermediários (HIs), como no caso de vários nematoides da família Angiostrongylidae. O objetivo deste estudo foi investigar a presença de larvas de G. paralysans em gastrópodes terrestres para avaliar seu papel no ciclo de vida do parasito. Amostras de gastrópodes terrestres (n = 835) foram coletadas em Punucapa, Valdivia, sul do Chile, onde casos de gurltiose foram relatados anteriormente. As amostras incluíram espécies das famílias Arionidae, Limacidae, Helicidae e Milacidae. Todos os gastrópodes foram submetidos à digestão enzimática para isolar as larvas de G. paralysans. 10% das amostras foram analisadas, utilizando-se seminested PCR para o gen 28S RNAr de G. paralysans, enquanto 2,6% foram analisados ​​por exame histopatológico. Os resultados indicaram ausência de G. paralysans em todos os três métodos. Os dados permitem concluir que são necessários mais estudos para avaliar espécies específicas de gastrópodes aquáticos ou nativos, que atuam como possíveis hospedeiros intermediários nessa localização geográfica.

Angiostrongylus (Parastrongylus) cantonensis en huéspedes intermediarios y definitivos en Ecuador, 2014-2017 / Angiostrongylus (Parastrongylus) cantonensis on intermediate and definitive hosts in Ecuador, 2014-2017

Resumen Introducción. Angiostrongylus cantonensis es un serio problema de salud pública y está ampliamente distribuido en el país. Cuando el parásito infecta a los caracoles terrestres Achatina, se enquista en su interior y puede infectar accidentalmente a las personas y otros mamíferos. Objetivo. Establecer la distribución geográfica de A. cantonensis en huéspedes intermediarios (Achatina fulica) y definitivos (Rattus spp.) en Ecuador entre el 2014 y el 2017. Materiales y métodos. Se recolectaron 2.908 ejemplares de A. fulica en 16 provincias utilizando el método de captura por unidad de esfuerzo durante 30 minutos. Se capturaron 211 ejemplares de las especies huéspedes, de los cuales 20 eran Rattus rattus y 191 R. norvegicus. Los ejemplares fueron transportados para su análisis al Instituto Nacional de Salud Pública e Investigación en Guayaquil. En los tejidos del caracol se identificaron y se contabilizaron larvas L3 que luego se inocularon en ratas de laboratorio para reproducir el ciclo de vida. En los roedores se disecaron los cerebros, los corazones, las arterias pulmonares y los pulmones, y se identificaron los parásitos por morfología taxonómica. Resultados. De los caracoles recolectados se encontraron 441 positivos para A. cantonensis (15,2 %) y un total de 6.166 larvas L3. En los ejemplaresRattus spp. capturados (211), 77 (36,5 %) estaban infectados con A. cantonensis, con un total de 220 parásitos (larvas L4-L5 y adultos). Conclusiones. Se constató la presencia de A. cantonensis en varias provincias, lo que confirma el carácter endémico de esta zoonosis en el territorio nacional. La presencia de Rattus spp., huésped definitivo del parásito, y de huéspedes intermediarios, indica el potencial zoonótico de esta infección parasitaria.

Abstract Introduction: Angiostrongylus cantonensis is a serious public health problem and is widely distributed in the country. When the parasite infects the snails, it becomes deeply embedded in their interior and accidentally, it can infect people and other mammals. Objective: To establish the geographical distribution of A. cantonensis intermediate hosts (Achatina fulica) and definitive hosts (Rattus spp.) in Ecuador from 2014 to 2017. Materials and methods: We collected 2,908 A. fulica specimens in 16 provinces using the capture method per unit of effort for 30 minutes. We captured 211 hosts of which 20 were Rattus rattus and 191 R. norvegicus. The specimens were transported to the Instituto Nacional de Salud Pública e Investigación in Guayaquil where the larvae L3 were identified and counted in the tissues of the snail, which were then inoculated in laboratory rats to reproduce the life cycle. In the rodents, the brains, hearts, lung arteries and lungs were dissected, and the parasites were identified by taxonomic morphology. Results: Of the snails harvested, 441 were positive for A. cantonensis (15.2%) and a total of 6,166 L3 larvae were found; 77 (36.5%) specimens of Rattus spp., were infected with A. cantonensis and a total of 220 parasites (L4-L5 larvae and adult worms) were collected. Conclusions: We confirmed the presence of A. cantonensis in several provinces, which ratifies the endemic nature of this zoonosis in the national territory. Rattus spp. specimens constitute the definitive hosts of the parasite, which together with the presence of intermediate hosts, indicates the zoonotic potential of this parasitic infection.

Angiostrongylus cantonensis infection in molluscs in the municipality of São Gonçalo, a metropolitan area of Rio de Janeiro, Brazil: role of the invasive species Achatina fulica in parasite transmission dynamics

The aim of this study was to analyse the infection dynamics ofAngiostrongylus cantonensisin its possible intermediate hosts over two years in an urban area in the state of Rio de Janeiro where the presence ofA. cantonensis had been previously recorded in molluscs. Four of the seven mollusc species found in the study were exotic.Bradybaena similariswas the most abundant, followed byAchatina fulica, Streptaxissp., Subulina octona, Bulimulus tenuissimus, Sarasinula linguaeformisand Leptinaria unilamellata. Only A. fulicaand B. similariswere parasitised by A. cantonensis and both presented co-infection with other helminths. The prevalence of A. cantonensisin A. fulicawas more than 50% throughout the study. There was an inverse correlation between the population size ofA. fulicaand the prevalence of A. cantonensisand abundance of the latter was negatively related to rainfall. The overall prevalence of A. cantonensisin B. similariswas 24.6%. A. fulicawas the most important intermediary host of A. cantonensisin the studied area andB. similariswas secondary in importance for A. cantonensistransmission dynamics.

First report of Angiostrongylus cantonensis (Nematoda: Metastrongylidae) in Achatina fulica (Mollusca: Gastropoda) from Southeast and South Brazil

The rat lungworm Angiostrongylus cantonensis is a worldwide-distributed zoonotic nematode that can cause human eosinophilic meningoencephalitis. Here, for the first time, we report the isolation of A. cantonensis from Achatina fulica from two Brazilian states: Rio de Janeiro (specifically the municipalities of Barra do Piraí, situated at the Paraiba River Valley region and São Gonçalo, situated at the edge of Guanabara Bay) and Santa Catarina (in municipality of Joinville). The lungworms were identified by comparing morphological and morphometrical data obtained from adult worms to values obtained from experimental infections of A. cantonensis from Pernambuco, Brazil, and Akita, Japan. Only a few minor morphological differences that were determined to represent intra-specific variation were observed. This report of A. cantonensis in South and Southeast Brazil, together with the recent report of the zoonosis and parasite-infected molluscs in Northeast Brazil, provide evidence of the wide distribution of A. cantonensis in the country. The need for efforts to better understand the role of A. fulica in the transmission of meningoencephalitis in Brazil and the surveillance of molluscs and rodents, particularly in ports, is emphasized.

Angiostrongilose abdominal: profilaxia pela destruiçäo das larvas infectantes em alimentos tratados com sal, vinagre ou hipoclorito de sódio / Abdominal angiostrongylosis: prophilaxis through treatment of food with solutions of saturated sodium chloride, vinegar and sodium hypochlorite

There is a high prevalence of accidental human infection with Angiostrongylus costaricensis in some areas in southern Brazil and sometimes it presents as severe intestinal disease. Prophylaxis is important since there is no medical treatment for the disease. The ingestion of fruits and vegetables contaminated with the mucous secretion of infected molluscs (the intermediate hosts) is one of the proposed modes of transmission. Third stage larvae were incubated at 5 degrees C for 12 hours, in solutions of saturated sodium chloride, vinegar and sodium hypochlorite 1.5 per cent. The larvae had their viability tested through inoculation into albino mice. The percentage of larvae that established infection were 0 per cent in the group treated with sodium hypochloride, 1.8 per cent with NaCl and 2.4 per cent with vinegar. In conclusion, all substances tested reduced the population of viable larvae and may be useful in food decontamination, as a prophylactic measure for abdominal angiostrongylosis.

Experimental infection of five subspecies of Oncomelania snails with Angiostrongylus cantonensis.

Five subspecies of Oncomelania snails, Oncomelania hupensis nosophora, O.h. hupensis, O.h.chiui, O.h.formosana and O.h.quadrasi, were experimentally exposed to the first stage larvae of Angiostrongylus cantonesis. The presence of third stage larvae was observed in all of the five subspecies of Oncomelania snails 20 days after infection. Infection rates of the third stage larvae of the parasite in Oncomelania snails were 38.0-40.0%. There were no differences in preferences among Oncomelania snails. The third stage larvae in Oncomelania snails almost distributed in kidney and intestine region, and most of the larvae were active and free in tissues. The distribution pattern of the larvae in Oncomelania snails was quite different from that in Achatina fulica and Ampullarium sp. These third stage larvae were ingested by rats, and developed to adults. These data suggest that Oncomelania snails may play important role when A. cantonensis will spread, and indicate the possibility of human infection with A. cantonensis.