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1.
Exp Parasitol ; 222: 108066, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33444570

RESUMO

Fasciolosis in ruminants is a relentless constraint in the livestock industry across the world. Immuno-prophylactic vaccines against fasciolosis may not come up in near future, rendering the control of this scourge with chemotherapy and snail population control. With the alarming threats of anti-fasciolid drug resistance reported from certain parts of the world; the control of fasciolosis should be directed towards the development of rapid and reliable diagnostic tools to execute the specific and discrete treatment. Understanding the epidemiology of Fasciola, its genomics and proteomics, host-parasite interplay, and advances in drug design research is vital for improving animal health that would ultimately succour to meet the ever-increasing demand for food. Due to possible differences in immune response depending on the species of the host and parasite, immuno-prophylactic studies in India should aim at achieving protective efficacy in buffalo against F. gigantica as workers from other countries concentrate primarily on vaccination of cattle and sheep against F. hepatica. This manuscript focused on the research that has been carried out in India for understanding the epidemiology, genetic diversity, immuno-diagnosis, and possible control measure in terms of immuno-prophylaxis and drug designing against tropical fasciolosis caused by Fasciola gigantica.


Assuntos
Fasciola/genética , Fasciolíase/epidemiologia , Ruminantes/parasitologia , Animais , Fasciola/classificação , Fasciolíase/diagnóstico , Fasciolíase/prevenção & controle , Humanos , Índia/epidemiologia , Prevalência , Caramujos/parasitologia , Vacinas
2.
J Plant Res ; 134(1): 77-89, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33387091

RESUMO

Some algae are known to grow on shellfish shells. Most of these have been reported in aquatic environments. The species specificity for substrate shells varies, and some algae grow only on the shells of a certain species of shellfish, such as Pseudocladophora conchopheria (Cladophorales, Ulvophyceae) on Lunella coreensis (Trochida, Gastropoda). There are very few reports of algae that grow on land snails. In this study, we discovered green algae growing on the shells of six species of door snails (Clausiliidae) from nine localities in Japan. These green algae formed a green mat composed of thalli embedded in the extracellular matrix. The thallus was composed of aggregated oval cells and peripheral branched filaments. The cells possessed a single parietal chloroplast with a pyrenoid surrounded by two starch sheaths and transversed by a thylakoid. Oil droplets in the cell and ring-like structures on the cell wall surface were frequently observed. The 18S rDNA sequences of all shell-attached algae on different clausiliid species from different localities were almost identical and formed a new clade in the family Kornmanniaceae (Ulvales, Ulvophyceae). No other algae forming visible colonies on the clausiliid shell were found. These findings indicate the presence of specificity between the alga and clausiliid shells. Based on the results of morphological observation and molecular phylogenetic analysis, we propose a new genus and new species of shell-attached green alga, Annulotesta cochlephila.


Assuntos
Clorófitas , Animais , Clorófitas/genética , DNA Ribossômico/genética , Japão , Filogenia , Caramujos
3.
Bull Environ Contam Toxicol ; 106(1): 153-159, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33392685

RESUMO

Soil properties largely control the fate of mercury (Hg), including the synthesis of neurovirulent methylmercury (MeHg). Here, the freshwater snail (Cipangopaludina cahayensis), a snail species commonly bred in flooded farmland, was used in a test of biotoxicity exposure to explore the effects of soil components on Hg bioavailability. The results show that snails incubated on the surface of slightly Hg-polluted flooded soil (2.0 mg/kg) have MeHg concentrations of 7.9 ± 1.5 mg/kg, which greatly exceed the limit of contaminants in food in China (0.5 mg/kg). The addition of ferrous disulfide can significantly increase the MeHg concentrations in soils while reducing the concentrations of total Hg (THg) and MeHg levels in snails by 59.1% and 64.3%, respectively. Peat-derived fulvic acid has the capacity to reduce the MeHg concentrations in soils and snails by 23.8% and 33.2%, respectively, whereas it increases the dissolved Hg levels in overlying water by 104.3%. Moreover, Fe-Mn oxides and humic acid can consistently reduce THg and MeHg concentrations in snails. Overall, freshwater snails bred in Hg-polluted areas may suffer from a high risk of Hg exposure, and importantly, some soil components such as ferrous disulfide and humic acid have strong inhibitory effects on Hg bioaccumulation in snails.


Assuntos
Mercúrio , Compostos de Metilmercúrio , Animais , Bioacumulação , China , Monitoramento Ambiental , Água Doce , Mercúrio/análise , Caramujos , Solo
4.
Proc Biol Sci ; 287(1941): 20201761, 2020 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-33352075

RESUMO

Individuals differ in personality and immediate behavioural plasticity. While developmental environment may explain this group diversity, the effect of parental environment is still unexplored-a surprising observation since parental environment influences mean behaviour. We tested whether developmental and parental environments impacted personality and immediate plasticity. We raised two generations of Physa acuta snails in the laboratory with or without developmental exposure to predator cues. Escape behaviour was repeatedly assessed on adult snails with or without predator cues in the immediate environment. On average, snails were slower to escape if they or their parents had been exposed to predator cues during development. Snails were also less plastic in response to immediate predation risk on average if they or their parents had been exposed to predator cues. Group diversity in personality was greater in predator-exposed snails than unexposed snails, while parental environment did not influence it. Group diversity in immediate plasticity was not significant. Our results suggest that only developmental environment plays a key role in the emergence of group diversity in personality, but that parental environment influences mean behavioural responses to the environmental change. Consequently, although different, both developmental and parental cues may have evolutionary implications on behavioural responses.


Assuntos
Comportamento Animal , Caramujos/fisiologia , Animais , Evolução Biológica , Pais , Personalidade , Comportamento Predatório
5.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 32(6): 551-558, 2020 Nov 19.
Artigo em Chinês | MEDLINE | ID: mdl-33325187

RESUMO

This report presented the endemic status of schistosomiasis in the People's Republic of China at a national level in 2019, and analyzed the data collected from the national schistosomiasis prevention and control system and 455 national schistosomiasis surveillance sites. Among the 12 provinces (municipality and autonomous region) endemic for schistosomiasis in China, Shanghai, Zhejiang, Fujian, Guangdong and Guangxi continued to consolidate the achievements of schistosomiasis elimination, Sichuan Province achieved transmission interruption, Jiangsu newly achieved the standard of transmission interruption and 5 provinces of Yunnan, Hubei, Anhui, Jiangxi and Hunan maintained transmission control by the end of 2019. There were 450 endemic counties (cities, districts) endemic for schistosomiasis, including 28 500 endemic villages covering 70 667 800 people at risk of infections. Among the 450 endemic counties (citis, districts), 66.89% (301/450), 28.44% (128/450) and 4.67% (21/450) kept the criteria of elimination, transmission interruption and transmission control of schistosomiasis, respectively. By the end of 2019, a total of 30 170 advanced schistosomiasis cases were documented in China. In 2019, a total of 12 090 712 individuals received inquiry examinations and 1 740 764 were positive; 5 158 369 individuals received serological tests and 89 753 were seropositive. A total of 327 475 individuals received stool examinations and 5 were positive, including one case of acute schistosomiasis. In 2019, snail survey was performed in 19 726 endemic villages in China and Oncomelania snails were found in 7 322 villages, accounting for 37.12% of all surveyed villages, with 6 villages with emerging snail habitats. Snail survey covered an area of 585 286.24 hm2 and 174 270.42 hm2 snail habitats were found, including emerging snail habitats of 64.20 hm2; however, no infected snails were identified. In 2019, a total of 605 965 bovines were raised in the schistosomiasis endemic areas of China, and 183 313 received serological examinations, with 1 176 positives detected, while 134 978 bovines received stool examinations, with 7 positives identified. In 2019, there were 28 557 patients with schistosomiasis receiving praziquantel chemotherapy, and expanded chemotherapy was given to 1 008 083 person-times; there were 7 bovines with schistosomiasis receiving praziquantel chemotherapy, and 296 053 herd-times expanded chemotherapy was given to bovines. In 2019, snail habitats at an area of 128 754.26 hm2 were given chemical treatment, and the actual area of chemical treatment was 69 605.55 hm2, while environmental improvements were performed in snail habitats covering an area of 2 847.00 hm2. Data from the 455 national schistosomiasis surveillance sites of China showed that the mean Schistosoma japonicum infection rates were both zero in humans and bovines in 2019, and no infected snails were found. The results demonstrate that the overall endemic situation of schistosomiasis remains at a lower infection level in China; however, there is still a risk of schistosomiasis transmission. To achieve the target set in the National Thirteenth Five-Year Plan for Schistosomiasis Control and consolidate the achievements of schistosomiasis control, precision control on schistosomiasis still needs to be reinforced in China.


Assuntos
Doenças Endêmicas , Esquistossomose Japônica , Esquistossomose , Animais , Bovinos/parasitologia , China/epidemiologia , Cidades , Humanos , Praziquantel/uso terapêutico , Esquistossomose/tratamento farmacológico , Esquistossomose/epidemiologia , Esquistossomose/veterinária , Caramujos/parasitologia
6.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 32(6): 565-568, 2020 Nov 25.
Artigo em Chinês | MEDLINE | ID: mdl-33325189

RESUMO

OBJECTIVE: To analyze the changing tendency in the endemic situation of schistosomiasis in the national surveillance sites of Hubei Province, so as to provide the scientific evidence for facilitating the progress towards the elimination of schistosomiasis in the province. METHODS: According to the National Schistosomiasis Surveillance Scheme (2014 version), a total of 65 national schistosomiasis surveillance sites were assigned in Hubei Province, and the Schistosoma japonicum infections in humans, domestic animals, snails and wild feces were monitored in these national surveillance sites from 2015 to 2019. All data pertaining to the surveillance results were descriptively analyzed. RESULTS: There were 151 159 person-time local residents and 70 928 person-time mobile populations screened for S. japonicum infections in the 65 national surveillance sites of Hubei Province from 2015 to 2019, and the seroprevalance of S. japonicum infections reduced from 3.45% (1 077/31 197) in 2015 to 1.57% (431/27 371) in 2019 among local residents and from 1.06% (98/9 249) in 2015 to 0.81% (116/14 318) in 2019 among mobile populations. During the period from 2015 through 2019, there were 22 egg-positive local residents and 2 egg-positive mobile populations identified in 2015, with 0.07% and 0.02% prevalence rates of S. japonicum infections, respectively. During the 5-year period, a total of 7 025 herd-time domestic animals examined for S. japonicum infections, with no infections detected, and a total of 2 035 wild feces were tested, with no egg-positives identified in the 65 national surveillance sites of Hubei Province. Snail survey was conducted covering 28 767.35 hm2 during the 5-year period, and the area of snail habitats ranged from 1 609.82 to 2 119.81 hm2. The mean density of living snails and occurrence of frames with snails reduced from 0.360 5 snails/0.1 m2 and 11.26% in 2015 to 0.175 9 snails/0.1 m2 and 8.43% in 2019, respectively, and no S. japonicum infection was found in snails during the 5-year period. In addition, no snails were found in the potential schistosomiasis transmission foci in the two national surveillance sites in the Three Gorges Dam. CONCLUSIONS: The overall endemic situation of schistosomiasis appears a tendency towards a decline in Hubei Province during the period from 2015 through 2019; however, the schistosomiasis transmission risk remains. Improving the surveillance system of schistosomiasis and increasing the sensitivity and performance of the surveillance system are required to provide insights into the implementation of precision control strategy and interventions in Hubei Province.


Assuntos
Doenças Endêmicas , Esquistossomose , Animais , China/epidemiologia , Fezes/parasitologia , Humanos , Gado , Prevalência , Esquistossomose/epidemiologia , Esquistossomose/veterinária , Esquistossomose Japônica , Caramujos/parasitologia
7.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 32(6): 640-642, 2020 Aug 12.
Artigo em Chinês | MEDLINE | ID: mdl-33325202

RESUMO

OBJECTIVE: To evaluate the effectiveness of Oncomelania snails control following the implementation of integrated schistosomiasis control measures in river channels connecting the Yangtze River in endemic areas of Nanjing City. METHODS: The river channels connecting the Yangtze River with snails in Nanjing City were selected as the study pilots. The integrated schistosomiasis control measures implemented in the study pilots were investigated by means of retrospective analyses and field surveys from 1998 to 2019, and the effectiveness of snail control was evaluated. RESULTS: Integrated control measures with emphases on environmental improvements including water resource projects for schistosomiasis control were implemented in the study pilots during the period from 1998 to 2019, including river bank concretion with 84.51 km in length, marshland cutting and dredging with 50.41 km in length, building 2 sluices and 3 overflow dams, digging one floodway and snail control with chemical treatment that covered an area of 3 370.80 hm2. No Schistosoma japonicum infection had been detected in snails since the completion of the integrated control measures. In addition, snails had been eliminated in 6 river channels connecting the Yangtze River until 2019, with the snail habitats reducing from 214.33 hm2 to 52.22 hm2 in 10 river channels connecting the Yangtze River and the snail density reducing to below 0.1 snails/0.1 m2 in snail-breeding river channels connecting the Yangtze River. CONCLUSIONS: The integrated schistosomiasis control measures with emphases on environmental improvements may effectively control snail breeding and spread in rivers connecting the Yangtze River in endemic areas of schistosomiasis; however, the maintenance of the project and snail surveillance and control should be intensified following the completion of the integrated schistosomiasis control measures.


Assuntos
Rios/parasitologia , Esquistossomose , Caramujos/parasitologia , Animais , China/epidemiologia , Reservatórios de Doenças/parasitologia , Humanos , Estudos Retrospectivos , Esquistossomose/epidemiologia , Esquistossomose/prevenção & controle , Esquistossomose Japônica
8.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 32(6): 646-648, 2020 Oct 26.
Artigo em Chinês | MEDLINE | ID: mdl-33325204

RESUMO

OBJECTIVE: To analyze the endemic situation of schistosomiasis in national surveillance sites of Zhenjiang City from 2015 to 2019, so as to provide the scientific basis for the consolidation of schistosomiasis control achievements and timely treatment of risk factors. METHODS: A total of 7 national schistosomiasis surveillance sites were assigned in Zhenjiang City from 2015 to 2019. According to the National Scheme for Schistosomiasis Surveillance (2014 version), Schistosoma japonicum infections were monitored in local residents, floating populations and livestock, and snail habitats were surveyed in Zhenjiang City from 2015 to 2019. The results of schistosomaisis surveillance in Zhenjiang City from 2015 to 2019 were analyzed. RESULTS: There were 15 848 and 7 779 person-times of local residents and floating populations receiving serological screening of schistosomiasis in 7 national surveillance sites of Zhenjiang City from 2015 to 2019, and the seroprevalence rates were 0.95% to 1.75% and 0.14% to 0.91% among local residents and floating populations, respectively; however, no egg-positives were identified. A total of 1 885 herd-times of livestock were detected, and no egg-positives were found. During the 5-year period, snail survey was conducted in snail habitats and suspected snail habitats covering 3 333.79 hm2, and there were 108.71 hm2 snail habitats identified, including 50.97 hm2 re-emerging snail habitats. The density of living snails was 0.007 to 0.125 snails/0.1 m2 from 2015 to 2019, which showed a trend for a rise year by year (χ2 = 2 732.626, P < 0.01); however, no S. japonicum infections were detected in snails. CONCLUSIONS: The endemic situation of schistosomiasis has been maintained at a low level in Zhenjiang City, and schistosomiasis control achievements are consolidated. However, snails are widely distributed in the city, and there are still risk factors associated with schistosomiasis transmission. Further integrated interventions require to be reinforced to timely manage the risk of transmission of schistosomiasis and promote the progress towards elimination of schistosomiasis.


Assuntos
Vigilância da População , Esquistossomose , Estudos Soroepidemiológicos , Animais , China/epidemiologia , Cidades , Humanos , Gado/parasitologia , Esquistossomose/epidemiologia , Esquistossomose/prevenção & controle , Caramujos/parasitologia
9.
Zootaxa ; 4865(1): zootaxa.4865.1.1, 2020 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-33311199

RESUMO

Details are provided on 16 land snail genera, eight freshwater molluscan species, one estuarine species, 47 land snail species and varieties from New Zealand, and a further three land snail species putatively from New Zealand, which were described by Frederick Wollaston Hutton between 1879 and 1904. Original primary type material of 54 species was located during the present study. Lectotypes are designated for: Amphidoxa cornea Hutton, 1882, Amphidoxa jacquenetta Hutton, 1883, Amphidoxa perdita Hutton, 1883, Charopa cassandra Hutton, 1883, Cyclotus charmian Hutton, 1883, Fruticicola adriana Hutton, 1883, Gerontia cordelia Hutton, 1883, Gerontia pantherina Hutton, 1882, Microphysa pumila Hutton, 1882, Patula jessica Hutton, 1883, Patula lucetta Hutton, 1884, Patula sylvia Hutton, 1883, Patula tapirina Hutton, 1882, Pfeifferia cressida Hutton, 1883, Phrixgnathus celia Hutton, 1883, Phrixgnathus haasti Hutton, 1883, Phrixgnathus marginatus Hutton, 1882, Phrixgnathus phrynia Hutton, 1883, Rhytida australis Hutton, 1882, Strobila leiodon Hutton, 1882, Thalassia propinqua Hutton, 1882, Therasia thaisa Hutton, 1883, Therasia valeria Hutton, 1883 and Zonites helmsii Hutton, 1882. A neotype is designated for Rhytida citrina Hutton, 1882. Primary type material of the following taxa is figured herein for the first time: Amphidoxa lavinia Hutton, 1883, Cyclotus charmian Hutton, 1883, Fruticicola adriana Hutton, 1883, Leptopoma pannosa Hutton, 1882, Patula lucetta Hutton, 1884, Patula sylvia Hutton, 1883, Patula tapirina Hutton, 1882, Phacussa helmsi var. maculata Hutton, 1884, Phrixgnathus ariel Hutton, 1883, Phrixgnathus celia Hutton, 1883, Rhytida australis Hutton, 1882, Rissoa vana Hutton, 1873, Testacella vagans Hutton, 1882, Trochomorpha hermia Hutton, 1883 and Zonites helmsii Hutton, 1882. New taxonomic combinations introduced herein include Phacussa lucetta (Hutton, 1884) and Therasia propinqua (Hutton, 1882). Amphidoxa lavinia Hutton, 1883, Charopa cassandra Hutton, 1883, Patula timandra Hutton, 1883 and Trochomorpha hermia Hutton, 1883 are treated as junior synonyms of Tasmaphena sinclairii (Pfeiffer, 1846), Phacussa fulminata (Hutton, 1882), Fectola infecta (Reeve, 1852) and Advena campbellii (Gray, 1834), respectively.


Assuntos
Caramujos , Animais , Água Doce , Nova Zelândia
10.
Biol Bull ; 239(3): 209-217, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33347798

RESUMO

AbstractMany shell-bearing gastropods exhibit pre-capture behaviors when encountering predatory asteroid sea stars. As shown in this meta-analysis of 48 studies on 24 sea star and 100 gastropod and chiton species, almost three-quarters of prey escape by moving or tumbling away, whereas the remaining species clamp tightly to the substratum or otherwise resist. The aim of the present paper is to correlate these behaviors with predicted shell traits, including those with gravitational stability for species that escape on the substratum and those that clamp, and those with a strongly sculptured shell in species that resist sea star attacks. Escaping species and those that clamp have gravitationally stable shells, with the center of gravity located above the broad aperture and large foot. Species that resist have significantly more sculptured shells. All of these traits would also work well in encounters with other slow-moving predators, such as gastropods and planarians. Although the sea stars are generalist predators, and the gastropods have many enemies besides sea stars, cool-water gastropods are well adapted to predatory sea stars on temperate and polar coasts, where most hard-bottom sea stars with molluscan diets occur. The prominence of escape among cool-water gastropods seems contradictory, given that locomotor speed rises with increasing temperature; but tropical gastropods rely more on armor than on escape, because of the prevalence of faster, more powerful predators in warm water. The black pigment of shells of many temperate prey species of sea stars might confer crypsis against these predators.


Assuntos
Comportamento Predatório , Caramujos , Animais , Estrelas-do-Mar , Temperatura
11.
Biol Bull ; 239(3): 164-173, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33347802

RESUMO

AbstractThe trophic ecology of the invasive apple snail Pomacea canaliculata was intensely investigated because of the impacts of its grazing on aquatic vegetation, including crops. However, this freshwater snail also gathers food from the water surface by using a pedal funnel, a distinctive trophic behavior called pedal surface collecting. We investigated the diel fluctuations of this trophic behavior through four whole-day field observations in a stream. We recorded the lowest pedal funnel frequencies during light hours and the highest after sunset, a pattern similar to that of general activity. We evaluated through laboratory experiments the influence of water temperature and velocity, photoperiod, and a possible endogenous rhythm on this behavior. Pedal funnels are formed within the whole temperature range in which this snail is active. The highest pedal funnel formation rates were recorded at 30 °C, but the food captured was the same regardless of temperature. Pedal funnels were not observed at water velocities above 0.12 m·s-1, but below this limit the rate and time spent in funnels remained constant with velocity. Despite the time of day, pedal funnels were scarce under constant artificial light, ruling out an endogenous rhythm. Both in the laboratory and in the stream, the highest levels of pedal funnels were observed during dark periods, probably as a strategy to avoid detection by visual predators. Pedal surface collecting on floating matter could represent an additional impact of invasive apple snails on freshwater ecosystems, but it could also be used for the specific delivery of molluscicides against them.


Assuntos
Ecossistema , Caramujos , Animais , Água Doce , Temperatura
12.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 32(5): 506-510, 2020 Jul 29.
Artigo em Chinês | MEDLINE | ID: mdl-33185063

RESUMO

OBJECTIVE: To investigate the distribution of Oncomelania snails in Four-Lake Basin of Hubei Province, so as to provide scientific evidence for the development of snail control interventions. METHODS: The snail distribution was surveyed by means of the retrospective study and cross-sectional survey in the Four-Lake Basin in Spring of 2016. The data pertaining to the endemic situation of schistosomiasis were collected and analyzed in the Four-Lake Basin from 2008 to 2018, and the associations of snail habitat areas with the prevalence of Schistosoma japonicum in humans and bovines were examined. RESULTS: There were 16 003 snail habitats in the 9 schistosomiasis-endemic counties (districts) in the Four-Lake Basin in 2016, covering an area of 246 million m2. The mean density of living snails was 0.622 5 snails/0.1 m2, which was relatively high in weed-type settings (0.688 0 snails/0.1 m2) and ditches (0.706 4 snails/0.1 m2). Type I (current snail habitats, 53.03%) and Ⅱ- Ⅳ (historical snail habitats, 46.97%) settings were predominant snail habitats. A big change was seen in snail habitats in dry farmland, marshland and paddy farmland, and environmental modification resulted in satisfactory snail control effectiveness. In addition, the area of snail habitats positively correlated with the changes in the prevalence of S. japonicum infections in humans (r = 0.842, P < 0.01) and livestock (r = 0.695, P < 0.01). CONCLUSIONS: The integrate strategy with an emphasis on the control of the source of S. japonicum infections results in remarkable snail control effectiveness in the Four-Lake Basin; however, there is a risk of re-emerging snail habitats.


Assuntos
Distribuição Animal , Lagos , Esquistossomose , Caramujos , Animais , Bovinos , China/epidemiologia , Estudos Transversais , Ecossistema , Helmintíase Animal/epidemiologia , Helmintíase Animal/prevenção & controle , Humanos , Estudos Retrospectivos , Esquistossomose/epidemiologia , Esquistossomose/prevenção & controle , Caramujos/parasitologia , Caramujos/fisiologia , Inquéritos e Questionários
13.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 32(5): 511-516, 2020 Oct 19.
Artigo em Chinês | MEDLINE | ID: mdl-33185064

RESUMO

OBJECTIVE: To investigate the implementation of schistosomiasis control activities in China during the coronavirus disease 2019 (COVID-19) epidemic, so as to evaluate the impact of COVID-19 epidemic on the national schistosomiasis control program in China. METHODS: On April 2020, 3 counties (districts) were randomly selected from each of the 12 schistosomiasis-endemic provinces (municipality, autonomous region), and a questionnaire survey was conducted to investigate the implementation of schistosomiasis control activities in these counties (districts) from January to March 2020. Then, the impact of the COVID-19 epidemics on the national schistosomiasis control program of China was evaluated using a comparative analysis approach. RESULTS: Among the 36 counties (cities, districts) sampled from 12 provinces (municipality, autonomous region), 66.67% were at a high and medium risk of COVID-19 epidemics. The implementation of schistosomiasis control activities assignment, human schistosomiasis examination and treatment, snail control with chemical treatment and health education reduced by 44.26% to 91.56% as compared to 2019 during the same time period, and the schistosomiasis control program was more affected by COVID-19 in transmission-controlled provinces. The gross funds invested into the schistosomiasis control program reduced by 23.39% in relative to the expected, while the total expenditure increased by 41.22%. In addition, all 36 surveyed counties (districts) considered that the COVID-19 epidemic had a short-term impact on the schistosomiasis control program, with the most predominant impact on schistosomiasis control activities assignment, human resources and monitoring of endemic situation of schistosomiasis. CONCLUSIONS: The COVID-19 epidemics affect the routine schistosomiasis control program across the endemic-foci of China. Policy and financial support should be strengthened to ensure the completion of the schistosomiasis control program.


Assuntos
Infecções por Coronavirus/epidemiologia , Pneumonia Viral/epidemiologia , Esquistossomose/prevenção & controle , Animais , Betacoronavirus , China/epidemiologia , Doenças Endêmicas/prevenção & controle , Humanos , Pandemias , Esquistossomose/epidemiologia , Caramujos/parasitologia
14.
An Acad Bras Cienc ; 92(suppl 2): e20181101, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33146259

RESUMO

The sewage snail Physa acuta, native to North America, is an effective invasive species around the world. In Chile, it was first reported in 2014 in the north central area of the country. So far, the species has not been recorded in southern Chile. Sampling performed in 2015 in three localities from Llanquihue Lake, Chilean Patagonia, only provided native freshwater snails. However, new collections performed in February 2018 in the same three sites were successful for physid specimens suggesting a biological invasion entailing a large southward range expansion of these snails. Here we performed morphological, microstructural and phylogenetic analyses to investigate whether the new samples belong to Physa acuta. The shell morphology, male copulatory complex and radula microstructure of the new material agree with those of the sewage snail. The molecular phylogenetic analyses using the cytochrome c oxidase subunit 1 (COI) gene confirmed morphological identification. We suggest to take prompt measures to prevent the expansion of Physa acuta in Llanquihue Lake or nearby aquatic ecosystems.


Assuntos
Ecossistema , Lagos , Animais , Chile , Masculino , Filogenia , Caramujos/genética
15.
Korean J Parasitol ; 58(5): 499-511, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33202502

RESUMO

Echinostome metacercariae were investigated in freshwater snails from 26 districts in 7 provinces of upper northern Thailand. The species identification was carried out based on the morphologies of the metacercariae and adult flukes harvested from experimental hamsters, and on nucleotide sequences of internal transcribed spacer 2 (ITS2) and nicotinamide adenine dinucleotide dehydrogenase subunit 1 (nad1) genes. Twenty-four out of 26 districts were found to be infected with echinostome metacercariae in freshwater snails with the prevalence of 40.4%. The metacercariae were found in all 6 species of snails, including Filopaludina martensi martensi (21.9%), Filopaludina doliaris (50.8%), F. sumatrensis polygramma (61.3%), Bithynia siamensis siamensis (14.5%), Bithynia pulchella (38.0%), and Anenthome helena (4.9%). The echinostome metacercariae found in these snails were identified as Echinostoma revolutum (37-collar-spined) and Echinostoma macrorchis (45-collar-spined) morphologically and molecularly. The 2-week-old adult flukes of E. revolutum revealed unique features of the cirrus sac extending to middle of the ventral sucker and smooth testes. E. macrorchis adults revealed the cirrus sac close to the right lateral margin of the ventral sucker and 2 large and elliptical testes with slight indentations and pointed posterior end of the posterior testis. The ITS2 and nad1 sequences confirmed the species identification of E. revolutum, and the sequences of E. macrorchis have been deposited for the first time in Gen-Bank. The presence of the life cycle of E. macrorchis is a new record in Thailand and the snail F. doliaris as their second intermediate host seems to be new among the literature.


Assuntos
Cricetinae/parasitologia , Echinostoma/anatomia & histologia , Echinostoma/isolamento & purificação , Água Doce/parasitologia , Metacercárias/anatomia & histologia , Metacercárias/isolamento & purificação , Doenças Parasitárias em Animais/parasitologia , Caramujos/parasitologia , Animais , Sequência de Bases , Echinostoma/genética , Genes de Helmintos/genética , Metacercárias/genética , Prevalência , Tailândia/epidemiologia
16.
An Acad Bras Cienc ; 92(4): e20200715, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33237149

RESUMO

Plant-derived molluscicides have been indicated as biodegradable and low-cost strategies for control of Biomphalaria spp., intermediate host for the Schistosoma. This study evaluated whether the crude ethanolic extract of the Persea americana stem bark has molluscicidal activity against embryos, newly-hatched and adults of Biomphalaria glabrata. The extract was obtained, characterized and its toxicity analyzed by snail embryotoxicity test (144 h) and acute toxicity test with newly-hatching and adult snails (96 h). Results showed the presence of flavonoids, anthraquinone heterosides, coumarins and tannins in the crude ethanolic extract, which showed molluscicidal activity against all life cycle stages of B. glabrata. The LC50 for embryos, newly-hatched and adults were 27.06, 30.60 and 55.55 ppm, respectively. Embryos exposed to the extract at 50 ppm showed hatching inhibition and at 6.2 and 25 ppm had the highest rates of morphological alterations, such as shell malformations and coagulation of the perivitelline substance. Adult snails exposed to the extract at 75 ppm showed a peak of behavioral changes, such as lethargy and shell reclusion, in addition to answers like hemolymph release in most concentrations. Further studies are required, prioritizing toxicity testing on non-target organisms and further elucidation of the active molecules.


Assuntos
Biomphalaria , Lauraceae , Moluscocidas , Persea , Animais , Moluscocidas/toxicidade , Casca de Planta , Extratos Vegetais/farmacologia , Caramujos
17.
Zootaxa ; 4858(2): zootaxa.4858.2.11, 2020 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-33056238

RESUMO

Diplommatinidae Pfeiffer, 1857 is a speciose family of minute operculate land snails that includes more than 500 extant species occurring mainly in Southeastern Asia and northern Oceania with some species in tropical America and, arguably, in Madagascar (Kobelt 1902; Wenz 1938-1939; Haas 1961; Egorov. 2013; Yamazaki et al. 2013; Neubert Bouchet 2015; Nurinsiyah Hausdorf 2017; Páll-Gergely et al. 2017a; Greke, 2017). The fossil record of Diplommatinidae is very sparse; it was recorded from the Miocene of Poland (Harzhauser Neubauer 2018) and four species were recently described from Cretaceous Burmese amber, being the oldest known diplommatinids (Yu et al. 2018; Hirano et al. 2019; Bullis et al. 2020).


Assuntos
Âmbar , Caramujos , Animais , Fósseis
18.
PLoS One ; 15(10): e0239762, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33002035

RESUMO

The dilution effect can occur by a range of mechanisms and results in reduced parasite prevalence in host taxa. In invaded ecosystems, the dilution effect can benefit native species if non-native species, acting as resistant or less competent hosts, reduce rates of parasitic infections in native species. In field experiments, we assessed whether manipulating biomass of the non-native snail, Potamopyrgus antipodarum, caused a dilution effect by reducing trematode infections in three taxa of native snails. In contrast to many studies showing resistant or less competent non-native hosts can "dilute" or reduce infection rates, we found no evidence for a dilution effect reducing infection rates of any of the native snails. We suggest that a dilution effect may not have occurred because most trematode taxa are highly host specific, and thus the trematode transmission stages did not recognize the invasive snail as a possible host. In this case, community composition appears to be important in influencing the dilution effect.


Assuntos
Espécies Introduzidas , Caramujos , Animais , Biodiversidade , Dinâmica Populacional , Caramujos/parasitologia , Trematódeos , Infecções por Trematódeos/veterinária , Wyoming
19.
Zootaxa ; 4810(1): zootaxa.4810.1.8, 2020 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-33055915

RESUMO

There are eight described species in Phreatodrobia, minute, phreatic (subterranean aquatic) snails, all stygobitic and endemic to the Edwards-Trinity Aquifer System of Texas. Two species were described from river drift (Pilsbry Ferriss 1906) and the others more recently by sampling the water flowing from wells or springs (Hershler Longley 1986b; Hershler Longley 1987). Recent sampling from spring orifices and the hyporheic zone of streams have extended the known ranges of the phreatic snails of the region and encountered unknown snails (Alvear et al. 2020). Here we describe Phreatodrobia spica n. sp., a rarely encountered species with a large range of about 400 km (Figure 1). We find P. spica in samples with a diverse assemblage of phreatic animals including other species of Phreatodrobia, isopods, amphipods, coleopterans, and mites. Phreatodrobia spica is distinguished from congeners using morphological and molecular evidence and is characterized by an elevated, trochiform shell with unique sculpture that include spikes and pustules. It has an open umbilicus and a complete, reflected lip that is sometimes appressed to the body whorl.


Assuntos
Anfípodes , Isópodes , Animais , Rios , Caramujos , Texas
20.
PLoS One ; 15(9): e0239264, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32925984

RESUMO

Cryptozona siamensis, one of the most widespread land snails, is native to Thailand, and plays a key role as an agricultural pest and intermediate host for Angiostrongylus spp. However, its genetic diversity and population structure has not yet been investigated, and are poorly understood. Therefore, a genetic analysis of the C. siamensis population in Thailand was conducted, based mitochondrial 16S rRNA (402 bp) and COI (602 bp) gene fragment sequences. Cryptozona siamensis randomly collected from 17 locations in four populations across Thailand, between May 2017 and July 2018. Fifty-eight snails were used to examine the phylogeny, genetic diversity, and genetic structure. The maximum likelihood tree based on the 16S rRNA and COI fragment sequences revealed two main clades. A total of 14 haplotypes with 44 nucleotide variable sites were found in the 16S rRNA sequences, while 14 haplotypes with 57 nucleotide variable sites were found in the COI sequences. The genetic diversity of C. siamensis in term of the number of haplotypes and haplotype diversity, was found to be high but the nucleotide diversity showed low levels of genetic differentiation for the COI sequence as also noted with the 16S rRNA sequence. The population genetic structure of C. siamensis revealed genetic difference in most populations in Thailand. However, low genetic difference in some populations may be due to high gene flow. This study provides novel insights into the basic molecular genetics of C. siamensis.


Assuntos
Variação Genética/genética , Genética Populacional , RNA Ribossômico 16S/genética , Caramujos/genética , Angiostrongylus/patogenicidade , Animais , DNA Mitocondrial/genética , Haplótipos/genética , Filogenia , Análise de Sequência de DNA , Caramujos/parasitologia , Tailândia
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