Infection Rates of Fasciola Intermediate Host Snail Species and Their Distribution in Africa: A Systematic Review and Meta-Analysis.
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ABSTRACT:
SUBMITTER: Hadebe MI
PROVIDER: S-EPMC10610779 | biostudies-literature | 2023 Oct
REPOSITORIES: biostudies-literature
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Infection Rates of Fasciola Intermediate Host Snail Species and Their Distribution in Africa: A Systematic Review and Meta-Analysis.
Hadebe Mpumelelo Ian MI Manyangadze Tawanda T Kalinda Chester C Mindu Tafadzwa T Chimbari Moses John MJ
Tropical medicine and infectious disease 20231006 10
This systematic review and meta-analysis aimed to collate the infection rates of <i>Fasciola</i> spp. in intermediate host snails and their distribution in Africa. The overall infectivity prevalences of <i>Galba truncatula, Radix natalensis</i>, and <i>Pseudosuccinea columella</i> are 52%, 8%, and 3%, respectively. The intermediate host snails native to Africa (<i>R. natalensis</i> and <i>G. truncatula</i>) have been examined more than the invasive <i>P. columella</i>. The studies included in th ...[more]
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Project description:BACKGROUND:Snails such as Galba truncatula are hosts for trematode flukes causing fascioliasis, a zoonosis that is a major public health problem. Galba truncatula has recently been shown to be a cryptic species complex. African populations of Galba spp. are not yet studied using molecular assessments and is imperative to do so and reconstruct the centre of origin of Galba and to understand when and by what means it may have colonized the highlands of Africa and to what extent humans might have been involved in that process. METHODS:Samples from all known sub-ranges throughout Africa and new samples from Europe and Asia were obtained. We used a combination of two mitochondrial (cox1 and 16S) and one nuclear (ITS2) markers and phylogenetic, divergence time estimates and phylogeographical methods to determine the identity and biogeographical affinities. We also reconstructed the colonization history including the likely mode of dispersal and tested for the presence of cryptic Galba species in Africa. RESULTS:Galba truncatula is restricted to the Palaearctic region of the continent, namely Morocco. All sub-Saharan populations proved to be a distinct species according to the phylogenetic analyses and genetic distance. We propose to use the existing name Galba mweruensis (Connolly, 1929) for this species which is morphologically indistinguishable from the other two species hitherto known to occur in northern Africa, i.e. G. truncatula and G. schirazensis. Sub-tropical Africa has been colonized only once in either the Pliocene and possibly Miocene. Diversification within G. mweruensis is dated to the Plio-Pleistocene and thus human-mediated dispersal can be ruled out for the initial colonization of the isolated mountain ranges. There are potentially even more cryptic species in high altitude areas of Africa as outlined by the distinctness of the population found at the top of Mt. Elgon, Uganda. CONCLUSIONS:From a novel genetic inspection of available African material, a hitherto neglected distinct species, G. mweruensis, now appears a major host of F. hepatica throughout sub-Saharan Africa. A closer examination of trematode parasites hosted by this species is needed in order to understand transmission patterns in highlands throughout eastern and southern Africa. We encourage future studies to inspect other high altitudes areas in Africa in light of parasites of either veterinary or medical importance.
| S-EPMC6894237 | biostudies-literature
Project description:The systematic review and meta-analysis were conducted to determine the estimates of the prevalence and infection rates of natural and experimental infections of amphistome species in intermediate host snails (IHs) across different continents. A search of peer-reviewed literature on natural and experimental infections of freshwater snails with amphistome species was conducted from four electronic databases from 1984 to 2023. The estimates of the prevalence and/or infection rates were based on 36 eligible peer-reviewed articles, which met the inclusion criteria and reported on natural and experimental infections of amphistome species in freshwater snails. The results showed that a total of 1,67,081 snail species from the peer-reviewed articles were examined for natural infections and 7,659 snail species for experimental infections. The overall pooled prevalence of amphistome infections from naturally infected snails was 2% (95% CI: 0-4), while the overall pooled prevalence of amphistome infections from infections was 40% (95% CI: 18-64). The highest pooled prevalence of natural infection was 3%, which was recorded in Europe (95% CI: 1-7%). The highest overall prevalence of naturally infected amphistome was 6% (95% CI: 0-20%) for Paramphistomum epiclitum. The Americas had the highest pooled prevalence of experimental amphistome infection among freshwater snails (66%; 95% CI: 26-96%). The highest pooled infection rate of 65% (95% CI: 12-100%) was recorded for Paramphistomum cervi in experimental infections. Galba truncatula was the only snail that qualified for meta-analysis for natural infection with Calicophoron daubneyi, with a pooled prevalence of 3% (95% CI: 1-8%). Galba truncatula infected with C. daubneyi and P. cervi, and Bulinus tropicus infected with Calicophoron microbothrium in the experimental infection qualified for the meta-analysis, with an overall infection rate of 66% (95% CI: 34-92%) and 30% (95% CI: 0-74%), respectively. The pooled prevalence of amphistome species infection in the intermediate host (IH) snails based on detection techniques was higher with PCR compared to the dissection and shedding of cercariae. The results from the quality effects model revealed a high heterogeneity and publication bias between studies. This meta-analysis provided valuable insights into the prevalence and infection rates of amphistome species in snail IHs across different geographical regions.
| S-EPMC11216035 | biostudies-literature
Project description:BackgroundFasciola hepatica is a highly prevalent parasite infecting livestock in Great Britain, while Calicophoron daubneyi is an emerging parasite within the GB livestock industry. Both F. hepatica and C. daubneyi require an intermediate host snail to complete their life-cycles and infect ruminants; however, there has been no confirmation of the intermediate host of C. daubneyi in GB, while there are questions regarding alternative host snails to Galba truncatula for F. hepatica. In this study, PCR was used to identify C. daubneyi hosting snail species on Welsh pastures and to identify any alternative snail species hosting F. hepatica.FindingsTwo hundred and sixty four snails were collected between May-September 2015 from six farms in mid-Wales known to have livestock infected with C. daubneyi and F. hepatica. Fifteen out of 134 G. truncatula were found positive for C. daubneyi, one of which was also positive for F. hepatica. Three snail species were found positive for F. hepatica [18/134 G. truncatula, 13/52 Radix balthica, and 3/78 Potamopyrgus antipodarum (New Zealand mud snail)], but no evidence of C. daubneyi infection in the latter two species was found.ConclusionThis study indicates that G. truncatula is a host for C. daubneyi in GB. Galba truncatula is also an established host of F. hepatica, and interactions between both species at intermediate host level could potentially occur. Radix balthica and P. antipodarum were found positive for F. hepatica but not C. daubneyi. This could indicate a role for alternative snail species other than G. truncatula in infecting pastures with F. hepatica in GB.
| S-EPMC4688931 | biostudies-literature
Project description:Complete mitochondrial (mt) genomes and the gene rearrangements are increasingly used as molecular markers for investigating phylogenetic relationships. Contributing to the complete mt genomes of Gastropoda, especially Pulmonata, we determined the mt genome of the freshwater snail Galba pervia, which is an important intermediate host for Fasciola spp. in China. The complete mt genome of G. pervia is 13,768 bp in length. Its genome is circular, and consists of 37 genes, including 13 genes for proteins, 2 genes for rRNA, 22 genes for tRNA. The mt gene order of G. pervia showed novel arrangement (tRNA-His, tRNA-Gly and tRNA-Tyr change positions and directions) when compared with mt genomes of Pulmonata species sequenced to date, indicating divergence among different species within the Pulmonata. A total of 3655 amino acids were deduced to encode 13 protein genes. The most frequently used amino acid is Leu (15.05%), followed by Phe (11.24%), Ser (10.76%) and IIe (8.346%). Phylogenetic analyses using the concatenated amino acid sequences of the 13 protein-coding genes, with three different computational algorithms (maximum parsimony, maximum likelihood and bayesian analysis), all revealed that the families Lymnaeidae and Planorbidae are closely related two snail families, consistent with previous classifications based on morphological and molecular studies. The complete mt genome sequence of G. pervia showed a novel gene arrangement and it represents the first sequenced high quality mt genome of the family Lymnaeidae. These novel mtDNA data provide additional genetic markers for studying the epidemiology, population genetics and phylogeographics of freshwater snails, as well as for understanding interplay between the intermediate snail hosts and the intra-mollusca stages of Fasciola spp..
| S-EPMC3406003 | biostudies-literature
Project description:There is a need for recent information on intermediate snail hosts of schistosomes in The Gambia; the previous studies were conducted over three decades ago. This study assessed the incidence, species diversity, distribution and infection status of schistosome intermediate snail hosts in the country. Malacological surveys were conducted in all 5 regions of The Gambia: Central River Region (CRR), Upper River Region (URR), Western Region (WR), Lower River Region (LRR) and North Bank Region (NBR). Sampling of snails was undertaken at 114 sites that included permanent water bodies such as streams (bolongs), rice fields, irrigation canals and swamps; and temporal (seasonal) laterite pools. Ecological and physicochemical factors of sites were recorded. Snails were identified morphologically and screened for schistosome infections using molecular techniques. Freshwater snails were found at more than 50% (60/114) of sites sampled. While three species of Bulinus were collected, no Biomphalaria snails were found in any of the sites sampled. Of the total 2877 Bulinus snails collected, 75.9% were identified as Bulinus senegalensis, 20.9% as Bulinus forskalii and 3.2% as Bulinus truncatus. Seasonal pools produced the largest number of snails, and CRR was the region with the largest number of snails. Bulinus senegalensis was found more in seasonal pools as opposed to permanent sites, where B. forskalii and B. truncatus were observed to thrive. Bulinus snails were more common in seasonal sites where aquatic vegetation was present. In permanent sites, the abundance of snails increased with increase in water temperature and decrease in water pH. Bulinus senegalensis was found infected with both S. haematobium and S. bovis, while B. forskalii and B. truncatus had only S. bovis infection. While the human parasite S. haematobium was restricted to just four sites, the livestock parasite S. bovis had a much more widespread geographical distribution across both CRR and URR. This new information on the distribution of intermediate snail hosts of schistosomes in The Gambia will be vital for the national schistosomiasis control initiative.
| S-EPMC8516291 | biostudies-literature
Project description:BackgroundThere is a need for current and more detailed information on the distribution of Biomphalaria pfeifferi snails in East Africa's river systems. B. pfeifferi is arguably the most important snail intermediate host in the transmission of schistosomiasis, a disease ranked second to malaria in terms of tropical diseases of public health importance.MethodsWe assessed the occurrence and geographical distribution of B. pfeifferi snails in Kenya, Uganda and Tanzania. Maximum entropy modelling was used to predict the potential distribution of B. pfeifferi snails and malacological surveys were conducted guided by MaxEnt predictions and information from previous studies. Malacological surveys were conducted at a total of 172 sites, including streams, rivers, dams, irrigation schemes and springs over a 3-y period from 2018 to 2020, with geospatial, ecological and physicochemical information recorded for each site.ResultsB. pfeifferi snails were found at 23 of the 172 sites and inhabited a variety of habitat types. Of the 23 sites where B. pfeifferi snails were found, 15 (65.2%) were streams, 3 rivers (13.04%), 2 dams (8.7%), 2 springs (8.7%) and 1 an irrigation scheme (4.35%). B. pfeifferi abundance showed a significant positive correlation with increasing water temperature and decreasing water depth. In Kenya, B. pfeifferi snails were found around the Lake Victoria basin, the Mwea irrigation scheme and in parts of the former Eastern Province of Kenya. In Uganda, B. pfeifferi snails were found in Jinja District, Ntoroko District and Soroti District. In Tanzania, B. pfeifferi snails were found in the Iringa, Tabora and Kigoma Regions. We observed moderate to high prevalence of Schistosoma mansoni infection, with S. mansoni-infected snails found at 11 of 23 sites and with an average prevalence of 24.9% at infected sites. In Kenya, S. mansoni-infected snails were found in the Lake Victoria basin (22.5% prevalence at infected sites) and the former Eastern Province (13.5% prevalence at infected sites). In Uganda, infected snails were found in Ntoroko District (100% infected) and Soroti District (20% infected). In Tanzania, infected snails were found in the Kigoma Region, with a prevalence of 10% at the infected site.ConclusionThis information on the distribution of B. pfeifferi snails and S. mansoni infection in East Africa's river systems can aid in developing better prevention and control strategies for human schistosomiasis. Regular surveys of the river systems for snail intermediate hosts followed by molecular detection of schistosome infection could form a basis for the development of a prompt and cost-effective surveillance system for schistosomiasis in the region.
| S-EPMC11887620 | biostudies-literature
Project description:BackgroundWith the closure of the Three Gorges Dam in 2003 the hydrology of Poyang Lake was altered dramatically leading to significant changes in the environment. In order to assess the impact on schistosomiasis this study assessed the spatial and temporal patterns of the snail intermediate host, Oncomelania hupensis in the Poyang Lake tributaries. The results of the study have important implications for future snail control strategies leading to disease elimination.MethodsThe marshland area surrounding Poyang Lake was divided randomly into 200 × 200 m vector grids using ArcGIS software, and the surveyed grids were randomly selected by the software. The snail survey was conducted in each selected grid using a survey frame of 50 × 50 m with one sideline of each grid serving as the starting line. No less than ten frames were used in each surveyed grid with Global Positioning System (GPS) recordings for each. All snails in each frame were collected to determine infection status by microscopy. Altitude data for all frames were extracted from a lake bottom topographic map in order to analyze the average altitude. All snail survey data were collected and statistically analyzed with SPSS 20.0 software in order to determine the difference of the percentage of frames with living snails and mean density of living snails in different regions of Poyang Lake. The altitude of the snail-infested marshlands and snail dens were subsequently identified.ResultsA total of 1159 potential snail sampling grids were surveyed, of which 15 231 frames (0.1 m2/frame) were investigated. 1241 frames had live Oncomelania snails corresponding to 8.15% of the total number of frames. The mean density of living snails was 0.463/0.1 m2 with a maximum of 57 snails per frame. The percent of frames with snails in the southern sector (8.13%) of Poyang Lake did not differ statistically from the north (8.21%). However, the mean density of live snails in the northern sector (0.164/0.1 m2) of the lake was statistically higher (F = 6.727; P = 0.010) than the south (0.141/0.1 m2). In the south of the lake, the elevation of snail-inhabited marshland ranged between 11 - 16 m, and could be further subdivided into two snail-concentrated belts at 12-13 m of elevation and 15-16 m of elevation respectively. In the north of the lake, the elevation of snail-inhabited marshland ranged between 9- 16 m with the elevation of 12-14 m being the snail-concentrated zone.ConclusionsThe elevation of snail-infested marshlands in the Poyang Lake region ranged from 9 to 16 m. The snail distribution and habitat has moved north of the lake and to a lower altitude due to changes in the water level post dam closure. Based on the current geological features of the snail habitant focused mollusciciding should occur in snail dense northern regions with frequent bovine and human traffic. Targeting these identified 'hotspots' of transmission will assist in elimination efforts.
| S-EPMC6440081 | biostudies-literature
Project description:Fasciola-induced fascioliasis is a zoonotic disease with significant health and economic impacts on humans and livestock. Freshwater Lymnaea snails serve as intermediate hosts, contributing to the increasing prevalence of fascioliasis in cattle in coastal areas. The salinity tolerance of Lymnaea snails was investigated along with their distribution and Fasciola infection rates in both snails and grazing cattle in Ben Tre, Tra Vinh, and Soc Trang provinces in Mekong Delta, Vietnam, where seawater reversely enters into the paddy field during the dry season. Lymnaea snails were collected from 53 communes across the three provinces and analyzed for Fasciola larval infections. Additionally, cattle fecal samples were examined for the presence of Fasciola eggs. The salinity levels in the study areas ranged from 0.03% to 1.90%. In total, 1,152 Lymnaea snails including L. viridis and L. rubiginosa were collected. The maximum salinity levels of L. viridis and L. rubiginosa habitats were 0.64% and 0.74%, respectively. The Fasciola infection rates of L. viridis were 2.0% in low-salinity areas and 3.7% in high-salinity areas, whereas no L. rubiginosa infections were detected in either salinity area. The prevalence of cattle fascioliasis in high-salinity areas (35.7%) was similar to low-salinity areas (32.9%). This study is the first to demonstrate that L. viridis can thrive and sustain Fasciola transmission under high-salinity conditions, suggesting the salinity tolerance of these intermediate host snails as a key factor contributing to the expansion of fascioliasis in high-salinity coastal areas.
| S-EPMC11903356 | biostudies-literature
Project description:Schistosomiasis, a neglected tropical disease (NTD), is one of the most prevalent parasitoses in the World. Certain freshwater snail species are the intermediate host in the life cycle of schistosome species. Controlling snails employing molluscicides is an effective, quick, and convenient intervention strategy to prevent the spread of Schistosoma species in endemic regions. Advances have been made in developing both synthetic molluscicides and molluscicides derived from plants. However, at present, the development of molluscicides is not adapted to the actual demand for snails and schistosoma controlling. We undertake a systematic review of exploitation and application of synthetic molluscicides and molluscicides derived from plants to combat intermediate host snails. The detailed molluscicidal activity, structure-activity relationship, structural feature, and possible mechanism of some molluscicides are also highlighted, which may afford an important reference for the design of new, more effective molluscicides with low environmental impact and realize the aim of controlling schistosome at transmission stages.
| S-EPMC8418967 | biostudies-literature
Project description:IntroductionA number of studies have attempted to predict the effects of climate change on schistosomiasis risk. The importance of considering different species of intermediate host snails separately has never previously been explored.MethodsAn agent-based model of water temperature and Biomphalaria pfeifferi population dynamics and Schistosoma mansoni transmission was parameterised to two additional species of snail: B. glabrata and B. alexandrina.ResultsSimulated B. alexandrina populations had lower minimum and maximum temperatures for survival than B. pfeifferi populations (12.5-29.5°C vs. 14.0-31.5°C). B. glabrata populations survived over a smaller range of temperatures than either B. pfeifferi or B. alexandrina (17.0°C-29.5°C). Infection risk peaked at 16.5°C, 25.0°C and 19.0°C respectively when B. pfeifferi, B. glabrata and B. alexandrina were simulated. For all species, infection risk increased sharply once a minimum temperature was reached.ConclusionsThe results from all three species suggest that infection risk may increase dramatically with small increases in temperature in areas at or near the currents limits of schistosome transmission. The effect of small increases in temperature in areas where schistosomiasis is currently found will depend both on current temperatures and on the species of snail acting as intermediate host(s) in the area. In most areas where B. pfeifferi is the host, infection risk is likely to decrease. In cooler areas where B. glabrata is the host, infection risk may increase slightly. In cooler areas where B. alexandrina is the host, infection risk may more than double with only 2°C increase in temperature. Our results show that it is crucial to consider the species of intermediate host when attempting to predict the effects of climate change on schistosomiasis.
| S-EPMC4079337 | biostudies-literature