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Memorias Do Instituto Oswaldo Cruz Nov 2011Molecular techniques can aid in the classification of Biomphalaria species because morphological differentiation between these species is difficult. Previous studies...
Molecular techniques can aid in the classification of Biomphalaria species because morphological differentiation between these species is difficult. Previous studies using phylogeny, morphological and molecular taxonomy showed that some populations studied were Biomphalaria cousini instead of Biomphalaria amazonica. Three different molecular profiles were observed that enabled the separation of B. amazonica from B. cousini. The third profile showed an association between the two and suggested the possibility of hybrids between them. Therefore, the aim of this work was to investigate the hybridism between B. cousini and B. amazonica and to verify if the hybrids are susceptible to Schistosoma mansoni. Crosses using the albinism factor as a genetic marker were performed, with pigmented B. cousini and albino B. amazonica snails identified by polymerase chain reaction-restriction fragment length polymorphism. This procedure was conducted using B. cousini and B. amazonica of the type locality accordingly to Paraense, 1966. In addition, susceptibility studies were performed using snails obtained from the crosses (hybrids) and three S. mansoni strains (LE, SJ, AL). The crosses between B. amazonica and B. cousini confirmed the occurrence of hybrids. Moreover, hybrids can be considered potential hosts of S. mansoni because they are susceptible to LE, SJ and AL strains (4.4%, 5.6% and 2.2%, respectively). These results indicate that there is a risk of introducing schistosomiasis mansoni into new areas.
Topics: Animals; Biomphalaria; Chimera; Disease Vectors; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Schistosoma mansoni
PubMed: 22124558
DOI: 10.1590/s0074-02762011000700011 -
PloS One 2021Near Infrared Spectroscopy (NIRS) has been applied in epidemiological surveillance studies of insect vectors of parasitic diseases, such as the Dengue's mosquitoes....
Near Infrared Spectroscopy (NIRS) has been applied in epidemiological surveillance studies of insect vectors of parasitic diseases, such as the Dengue's mosquitoes. However, regarding mollusks, vectors of important worldwide helminth diseases such as schistosomiasis, fascioliasis and angiostrongyliasis, NIRS studies are rare. This work proposes to establish and standardize the procedure of data collection and analysis using NIRS applied to medical malacology, i.e., to mollusk vectors identifications. Biomphalaria shells and live snails were analyzed regarding several operational aspects, such as: moisture, shell side and position of the live animal for acquisition of NIR spectra. Representative spectra of Biomphalaria shells and live snails were collected using an average of 50 scans per sample and resolution of 16 cm-1. For shells, the sample should first be dried for a minimum of 15 days at an average temperature of 26±1°C, and then placed directly in the equipment measurement window with its left side facing the light beam. Live animals should be dried with absorbent paper; placed into a glass jar, and analyzed similarly to the shells. Once standardized, the technique was applied aiming at two objectives: identification of Biomphalaria using only the shells and parasitological diagnosis for Schistosoma mansoni infection. The discrimination of the three Biomphalaria species intermediate hosts of S. mansoni only by shell has technical limit due to the scarcity of organic material. Nevertheless, it was possible to differentiate B. straminea from B. tenagophila and B. glabrata with 96% accuracy. As for the parasitological diagnosis, it was possible to differentiate infected mollusks shedding S. mansoni cercariae from the non-infected ones with 82, 5% accuracy. In conclusion, the Near Infrared Spectroscopy (NIR's) technique has proven to be an innovative and sound tool to detect infection by S. mansoni in the different species of Biomphalaria intermediate hosts.
Topics: Animals; Biomphalaria; Feasibility Studies; Spectroscopy, Near-Infrared
PubMed: 34762684
DOI: 10.1371/journal.pone.0259832 -
Geospatial Health Nov 2016The occurrence of schistosomiasis is directly linked to the presence of its snail intermediate host Biomphalaria spp. Knowledge of geographical distribution, habitats...
The occurrence of schistosomiasis is directly linked to the presence of its snail intermediate host Biomphalaria spp. Knowledge of geographical distribution, habitats and behaviour of these snails in relation to the climate is essential for guiding measures for disease prevention and control. This study aims to model the distribution of B. glabrata and B. straminea in schistosomiasis non-endemic areas of the metropolitan region of Recife (MRR) based on environmental data and estimates of snail distributions in endemic and neighbouring areas. We applied Kriging with the aim of determining the spatial distribution of these two snail species and MaxEnt for modelling their ecological behaviour. Kriging showed that the North and the Centre of the MRR were generally either snail-free or contained only B. straminea, while both snail species could be found in the South. MaxEnt supported our observation that the northern and southern coastal regions were favoured by B. glabrata and diurnal mean temperature variation; July rainfall and November rainfall were the three variables favouring Biomphalaria breeding sites that contributed the most in the predictive model we developed. The study showed the location of areas suitable to Biomphalaria spp. and therefore at potential risk, first for invasion of these snails and later for the development of new schistosomiasis- endemic areas. This information should be useful, not only to estimate expansion possibilities of this disease in the MRR, but also to point out the climatic variables that would contribute to this expansion, thereby allowing timely application of prevention and control measures.
Topics: Animals; Biomphalaria; Brazil; Disease Vectors; Population Surveillance; Schistosoma mansoni; Schistosomiasis mansoni; Snails
PubMed: 27903064
DOI: 10.4081/gh.2016.490 -
Infectious Diseases of Poverty Dec 2018Schistosomiasis is a common parasitic disease designated as a neglected tropical disease by the World Health Organization. Schistosomiasis mansoni is a form of the...
BACKGROUND
Schistosomiasis is a common parasitic disease designated as a neglected tropical disease by the World Health Organization. Schistosomiasis mansoni is a form of the disease that is caused by the digenean trematode Schistosoma mansoni, transmitted through Biomphalaria spp. as an intermediate host. Biomphalaria was introduced to Hong Kong, China in aquatic plants shipments coming from Brazil and the snail rapidly established its habitats in southern China. Earlier studies of Biomphalaria spp. introduced to southern China identified the snails as Biomphalaria straminea, one of the susceptible species implicated in S. mansoni transmission in South America. However, recent molecular investigations also indicated the presence of another South American species, B. kuhniana, which is refractory to infection. As such, it is important to identify accurately the species currently distributed in southern China, especially with emerging reports of active S. mansoni infections in Chinese workers returning from Africa.
METHODS
We combined morphological and molecular taxonomy tools to precisely identify Biomphalaria spp. distributed in Guangdong Province, southern China. In order to clearly understand the molecular profile of the species, we constructed a phylogeny using mtDNA data (COI and 16S rRNA sequences) from six populations of Biomphalaria spp. from Shenzhen City in Guangdong Province. In addition, we examined the external morphology of the shell and internal anatomy of the reproductive organs.
RESULTS
Both morphological and molecular evidences indicated a close affinity between Biomphalaria spp. populations from Guangdong and B. straminea from Brazil. The shell morphology was roughly identical in all the populations collected with rounded whorls on one side and subangulated on the other, a smooth periphery, an egg-shaped aperture bowed to one side, and a deep umbilicus. The shape and number of prostate diverticula (ranged from 11.67 to 17.67) in Guangdong populations supports its close affinity to B. straminea rather than B. kuhniana. Molecular analysis did not conflict with morphological analysis. Little genetic differentiation was observed within Biomphalaria populations collected. Phylogenetic analysis of COI and 16S rRNA haplotypes from snails collected and B. straminea sequences from Brazil and China using Bayesian inference revealed that Guangdong populations were clustered in one clade with B. straminea from Hong Kong of China and B. straminea from Brazil indicating their close affinity to each other.
CONCLUSIONS
Data obtained in the current study clearly show that the populations of Biomphalaria spp. investigated are B. straminea, and we assume that those snails were either introduced via passive dispersal from Hong Kong of China or as a result of multiple introduction routes from Brazil.
Topics: Animal Distribution; Animals; Biomphalaria; China; Haplotypes; Introduced Species; Phylogeny; RNA, Ribosomal, 16S
PubMed: 30526682
DOI: 10.1186/s40249-018-0505-5 -
Parasites & Vectors Jul 2017Schistosomiasis, also generally known as snail fever, is a parasitic disease caused by trematode flatworms of the genus Schistosoma. In Hong Kong and mainland China, the...
BACKGROUND
Schistosomiasis, also generally known as snail fever, is a parasitic disease caused by trematode flatworms of the genus Schistosoma. In Hong Kong and mainland China, the freshwater snail Biomphalaria straminea has been introduced and has the potential to transmit intestinal schistosomiasis caused by S. mansoni, a parasite of man which has a wide distribution in Africa and parts of the New World, especially Brazil. The first identification of B. straminea in Hong Kong dates back to the 1970s, and its geographical distribution, phylogenetic relationships, and infection status have not been updated for more than 30 years. Thus, this study aims to reveal the distribution and current infection status of B. straminea in contemporary Hong Kong.
METHODS
Snails were collected from different parts of Hong Kong from July 2016 to January 2017. Both anatomical and molecular methods were applied to identify B. straminea. Cytochrome c oxidase subunit 1 (cox1), internal transcribed spacer 1 (ITS1), 5.8S rDNA, internal transcribed spacer 2 (ITS2), and 16S ribosomal DNA (rDNA) were sequenced from individual snails and analyzed. To detect the presence of S. mansoni, both biopsy and PCR analyses were carried out.
RESULTS
Using both anatomical and molecular analyses, this study demonstrated the existence of black- and red-coloured shell B. straminea in different districts in the New Territories in Hong Kong, including places close to the mainland China border. None of the B. straminea (n = 87) investigated were found to be infected with S. mansoni when tested by biopsy and PCR. The Hong Kong B. straminea are genetically indistinguishable, based on the chosen molecular markers (cox1, ITS1-5.8S-ITS2, and 16S rDNA), and are similar to those obtained in mainland China and South America.
CONCLUSION
Biomphalaria straminea is now well established in freshwater habitats in Hong Kong. No evidence of infection with S. mansoni has been found. Surveillance should be continued to monitor and better understand this schistosomiasis intermediate host in mainland China and Hong Kong.
Topics: Animals; Biomphalaria; Brazil; China; DNA, Ribosomal; Disease Vectors; Hong Kong; Phylogeny; Polymerase Chain Reaction; Schistosoma mansoni; Schistosomiasis mansoni
PubMed: 28743308
DOI: 10.1186/s13071-017-2285-3 -
International Journal of Molecular... Mar 2023Schistosomiasis, or also generally known as bilharzia or snail fever, is a parasitic disease that is caused by trematode flatworms of the genus . It is considered by the... (Review)
Review
Schistosomiasis, or also generally known as bilharzia or snail fever, is a parasitic disease that is caused by trematode flatworms of the genus . It is considered by the World Health Organisation as the second most prevalent parasitic disease after malaria and affects more than 230 million people in over 70 countries. People are infected via a variety of activities ranging from agricultural, domestic, occupational to recreational activities, where the freshwater snails release cercariae larvae that penetrate the skin of humans when exposed in water. Understanding the biology of the intermediate host snail is thus important to reveal the potential spread of schistosomiasis. In this article, we present an overview of the latest molecular studies focused on the snail , including its ecology, evolution, and immune response; and propose using genomics as a foundation to further understand and control this disease vector and thus the transmission of schistosomiasis.
Topics: Animals; Humans; Schistosoma mansoni; Biomphalaria; Schistosomiasis mansoni; Snails; Schistosomiasis; Genomics
PubMed: 36902324
DOI: 10.3390/ijms24054895 -
Parasites & Vectors Mar 2020Snails of the genus Biomphalaria are intermediate hosts of Schistosoma mansoni, the causative agent of the human intestinal schistosomiasis. Two Biomphalaria species...
BACKGROUND
Snails of the genus Biomphalaria are intermediate hosts of Schistosoma mansoni, the causative agent of the human intestinal schistosomiasis. Two Biomphalaria species (Biomphalaria pfeifferi and Biomphalaria camerunensis) are involved in the transmission in Cameroon, where the disease is present nationwide. However, difficulty in the identification of both vectors impedes proper assessment of the epidemiological burden caused by each species. To overcome this issue, we designed a PCR-based molecular diagnostic tool to improve the identification of these species.
METHODS
We analyzed the internal transcribed spacer 2 (ITS2) region of Biomphalaria ribosomal DNA (rDNA) using polymerase chain reaction amplification (PCR) and restriction fragment length polymorphism (RFLP).
RESULTS
The amplification of the ITS2 region of Biomphalaria snails resulted in a 490 bp fragment and produced two profiles for each species after digestion with the restriction enzyme Hpa II. The profile 1 (Bc-HpaII-1: 212-bp and 139-bp bands) for B. camerunensis, was common in all the sampling points; the profile 2 (Bc-HpaII-2: 212-bp and 189-bp bands), was only observed in the Lake Monoun Njindoun sampling site. Biomphalaria pfeifferi profile 1 (Bpf-HpaII-1: 211-bp and 128-bp bands) was common in most of B. pfeifferi sampling points; the profile 2 (Bpf-HpaII-2: 289-bp and 128-bp bands) was only observed in Mokolo (Far North Cameroon).The second restriction enzyme TaqαI, revealed three band profiles, Bc-TaqαI-1 (243-bp, 136-bp and 118-bp bands) and Bc-TaqαI-2 (244-bp, 136-bp and 99-bp) for B. camerunensis and Bpf-TaqαI-1 (242-bp, 135-bp and 107-bp bands) for B. pfeifferi. Sequencing analysis revealed the occurrence of six haplotypes for B. camerunensis and three haplotypes for B. pfeifferi. The level of gene flow was low and the Biomphalaria populations were not in demographic expansion according to neutrality tests (Tajima's D and Fu's Fs).
CONCLUSIONS
The PCR-RFLP technique revealed genetic diversity in Biomphalaria snails, and the combination with the morphological method could improve the identification of B. pfeifferi and B. camerunensis in Cameroon. This could help focus on the infection to evaluate the transmission risk with respect of the different species and to develop efficient and cost-effective control measures.
Topics: Animals; Biomphalaria; Cameroon; DNA, Helminth; DNA, Ribosomal; Disease Vectors; Genetic Variation; Humans; Lakes; Molecular Diagnostic Techniques; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Schistosoma mansoni; Schistosomiasis mansoni
PubMed: 32228678
DOI: 10.1186/s13071-020-04033-1 -
Experimental Parasitology Jun 2020Infection with trematodes produces physiological and behavioural changes in intermediate snail hosts. One response to infection is parasitic castration, in which energy...
Infection with trematodes produces physiological and behavioural changes in intermediate snail hosts. One response to infection is parasitic castration, in which energy required for reproduction of the host is thought to be redirected to promote development and multiplication of the parasite. This study investigated some reproductive and biochemical parameters in the nervous (CNS) and ovotestis (OT) tissues of Biomphalaria alexandrina during the course of Schistosoma mansoni infection. Antioxidant and oxidative stress parameters including catalase (CAT), nitric oxide (NO) and lipid peroxidation (MDA) were measured. Levels of steroid hormones, including testosterone, progesterone and estradiol, were also assessed. Finally, flow cytometry was used to compare measures of apoptosis between control snails and those shedding cercariae by examining mitochondrial membrane potential with the stain 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimi-dazolylcarbocyanine iodide (JC-1) and poly(ADP-ribose) polymerase (PARP). Infection with S. mansoni caused a 47.7% reduction in the net reproductive rate (R) of B. alexandrina. CAT activity was increased in the CNS at 21 days post infection (dpi) but by 28 dpi it was reduced below control values. Also, CAT activity increased significantly in the OT at 14, 21 and 28 dpi. In CNS tissues, NO levels were reduced at 7 dpi, increased at 14 and 21 dpi, and reduced again at 28 dpi. The overall level of lipid peroxidation gradually increased during the course of infection to reach its highest levels at 28 dpi. Steroid hormone measurements showed that concentrations of testosterone and estradiol were reduced in the CNS tissues at 28 dpi, while those of progesterone were slightly increased in the CNS and OT tissues. The percentage of cells that positively stained with JC-1was significantly increased in CNS and OT tissues of infected snails while the percentage of cells positively stained with PARP was decreased compared to controls. Together, these findings indicate that infection initiates diverse biochemical and hormonal changes leading to loss of cells responsible for egg laying and reproduction in B. alexandrina.
Topics: Animals; Biomphalaria; Cercaria; Gonads; Host-Parasite Interactions; Nervous System; Schistosoma mansoni
PubMed: 32224062
DOI: 10.1016/j.exppara.2020.107887 -
Parasites & Vectors Jun 2017Schistosomiasis is hyper-endemic in the Lake Victoria basin; with intestinal schistosomiasis plaguing communities adjacent to the lake, where the intermediate host...
Longitudinal survey on the distribution of Biomphalaria sudanica and B. choanomophala in Mwanza region, on the shores of Lake Victoria, Tanzania: implications for schistosomiasis transmission and control.
BACKGROUND
Schistosomiasis is hyper-endemic in the Lake Victoria basin; with intestinal schistosomiasis plaguing communities adjacent to the lake, where the intermediate host snails live. The two intermediate host species of Schistosoma mansoni in the Mwanza region are Biomphalaria sudanica, found on the banks of the lakes, and B. choanomphala, found in the lake itself. There are few longitudinal surveys documenting changing abundance and differential transmission patterns of these Biomphalaria snails across seasons and years. We undertook 15 field surveys at 26 sites over four years to determine the parameters that influence Biomphalaria abundance, presence of S. mansoni-shedding snails and impact of schistosomiasis treatment interventions on transmission potential in the Mwanza region.
RESULTS
Statistical analysis revealed seasonal difference in the abundance of B. sudanica with the highest number of snails found in the dry season (Kruskal-Wallis χ = 37.231, df = 3, P < 0.0001). Water measurements were not associated with B. sudanica abundance; however, high levels of rainfall did have a negative effect on B. sudanica [coefficient effect -0.1405, 95% CI (-0.2666, -0.0144)] and B. choanomphala abundance [coefficient effect -0.4388, 95% CI (-0.8546, -0.0231)] potentially due to inundation of sites "diluting" the snails and influencing collection outcome. Biomphalaria sudanica snails were found at all sites whereas B. choanomphala were far more focal and only found in certain sites. Shedding Biomphalaria did not show any variation between dry and rainy seasons; however, a decrease in shedding snails was observed in year 4 of the study.
CONCLUSIONS
Biomphalaria sudanica is uniformly present in the Mwanza region whereas B. choanomphala is far more focal. Seasonality plays a role for B. sudanica abundance, likely due to its habitat preference on the banks of the lake, but not for B. choanomphala. The decrease in shedding Biomphalaria abundance in Year 4 could be linked to ongoing schistosomiasis treatment efforts in the neighbouring human populations. The highest number of shedding Biomphalaria was observed at sites with high levels of human movement. Prioritising snail control at such sites could greatly reduce transmission in these high-risk areas.
Topics: Animals; Biomphalaria; Disease Reservoirs; Ecosystem; Humans; Lakes; Longitudinal Studies; Population Density; Rain; Schistosoma mansoni; Schistosomiasis mansoni; Seasons; Tanzania; Water
PubMed: 28659165
DOI: 10.1186/s13071-017-2252-z -
Infectious Diseases of Poverty Jul 2016In Brazil, Biomphalaria glabrata, B. tenagophila, and B. straminea are naturally infected by the trematode Schistosoma mansoni, the causative agent of schistosomiasis.... (Review)
Review
In Brazil, Biomphalaria glabrata, B. tenagophila, and B. straminea are naturally infected by the trematode Schistosoma mansoni, the causative agent of schistosomiasis. Despite decades of governmental efforts through official control programs, schistosomiasis remains an important public health problem in the country: thousands of people are infected with the trematode each year and millions live in endemic areas. The World Health Organization recommends using a combination of molluscicide (niclosamide) and mass chemotherapy to control the transmission of schistosomiasis, with this treatment successfully reducing the morbidity of the disease. In the past, niclosamide has been used in official schistosomiasis control programs in Brazil. However, as B. glabrata recolonizes even after molluscicide application, the use of molluscicides has gradually decreased in the country until they were discontinued in 2002, mainly due to the rising global pressure to preserve the environment and the difficulties of obtaining licenses from the Brazilian Ministry of Environment to use toxic substances in aquatic ecosystems. Therefore, the discovery of new molluscicides, which could be more selective to Biomphalaria species and less harmful to the aquatic ecosystem, is necessary. In addition, political efforts to sensitize funders to provide grants for this field of research are required. In this context, this article aims to make a critical analysis of molluscicide application in schistosomiasis control programs in Brazil.
Topics: Animals; Biomphalaria; Brazil; Communicable Disease Control; Molluscacides; Niclosamide; Schistosoma mansoni; Schistosomiasis; Species Specificity
PubMed: 27374126
DOI: 10.1186/s40249-016-0153-6