A RAPID DIAGNOSTIC PCR ASSAY FOR THE DETECTION OF SCHISTOSOMA MANSONI IN THEIR SNAIL VECTORS.

Accurate detection of schistosome infections in snails is vital for epidemiologic and laboratory studies. Traditional microscopy methods to detect schistosomes in snails are hindered by long prepatent periods and snail survivorship, leading to inaccurate assessment of infections. A rapid, multiplexed PCR assay targeting Biomphalaria sudanica or Biomphalaria glabrata (internal control) and Schistosoma mansoni DNA is described.

Immune targets for schistosomiasis control identified by a genome-wide association study of East African snail vectors.

Schistosomiasis, afflicting >260 million people worldwide, could be controlled by preventing infection of freshwater snail vectors. Intestinal schistosomiasis, caused by , occurs predominantly in Sub-Saharan Africa and is vectored by and related species. Despite their importance in transmission, very little genomic work has been initiated in African snails, thus hindering development of novel control strategies.

Accelerating snail vector genomics.

The three most important genera of snails for the transmission of schistosomes are Bulinus, Biomphalaria and Oncomelania. Each of these genera, found in two distantly related families, includes species that act as the intermediate host for one of the three most widespread schistosome species infecting humans, Schistosoma haematobium, S. mansoni and S.

Development, validation, and pilot application of a high throughput molecular xenomonitoring assay to detect and other trematode species within freshwater snail hosts.

Schistosomiasis is a neglected tropical disease (NTD) caused by infection with parasitic trematodes of the genus that can lead to debilitating morbidity and mortality. The World Health Organization recommend molecular xenomonitoring of spp. freshwater snail intermediate hosts of to identify highly focal intestinal schistosomiasis transmission sites and monitor disease transmission, particularly in low-endemicity areas.

The genome and transcriptome of the snail : Immune gene diversification and highly polymorphic genomic regions in an important African vector of .

Background: Control and elimination of schistosomiasis is an arduous task, with current strategies proving inadequate to break transmission. Exploration of genetic approaches to interrupt transmission, the causative agent for human intestinal schistosomiasis in sub-Saharan Africa and South America, has led to genomic research of the snail vector hosts of the genus Few complete genomic resources exist, with African species being particularly underrepresented despite this being where the majority of infections occur. Here we generate and annotate the first genome assembly of sensu lato, a species responsible for transmission in lake and marsh habitats of the African Rift Valley.

Multi-strain compatibility polymorphism between a parasite and its snail host, a neglected vector of schistosomiasis in Africa.

Interactions between and its snail host are understood primarily through experimental work with one South American vector species, . However, 90% of schistosomiasis transmission occurs in Africa, where a diversity of species may serve as vectors. With the long-term goal of determining the genetic and ecological determinants of infection in African snail hosts, we developed genetic models of , a principal vector in the African Great Lakes.

Molecular characterization of schistosome cercariae and their snail hosts from Niakhar, a seasonal transmission focus in central Senegal.

and , two sympatric freshwater snails found in temporal ponds in Senegal, were thought to be involved in the transmission of and/or . To better understand the role of these species in the transmission of human and animal species, and were collected in 2015, during a malacological survey, from a temporal pond in Niakhar, central Senegal. Snails were induced to shed cercariae on two consecutive days.

Transmission and diversity of Schistosoma haematobium and S. bovis and their freshwater intermediate snail hosts Bulinus globosus and B. nasutus in the Zanzibar Archipelago, United Republic of Tanzania.

Background: The Zanzibar Archipelago (Pemba and Unguja islands) is targeted for the elimination of human urogenital schistosomiasis caused by infection with Schistosoma haematobium where the intermediate snail host is Bulinus globosus. Following multiple studies, it has remained unclear if B. nasutus (a snail species that occupies geographically distinct regions on the Archipelago) is involved in S.

Analytical and Clinical Assessment of a Portable, Isothermal Recombinase Polymerase Amplification (RPA) Assay for the Molecular Diagnosis of Urogenital Schistosomiasis.

Accurate diagnosis of urogenital schistosomiasis is crucial for disease surveillance and control. Routine diagnostic methods, however, lack sensitivity when assessing patients with low levels of infection still able to maintain pathogen transmission. Therefore, there is a need for highly sensitive diagnostic tools that can be used at the point-of-care in endemic areas.

Development of a Molecular Snail Xenomonitoring Assay to Detect and Infections in their Snail Hosts.

Schistosomiasis, a neglected tropical disease of medical and veterinary importance, transmitted through specific freshwater snail intermediate hosts, is targeted for elimination in several endemic regions in sub-Saharan Africa. Multi-disciplinary methods are required for both human and environmental diagnostics to certify schistosomiasis elimination when eventually reached. Molecular xenomonitoring protocols, a DNA-based detection method for screening disease vectors, have been developed and trialed for parasites transmitted by hematophagous insects, such as filarial worms and trypanosomes, yet few have been extensively trialed or proven reliable for the intermediate host snails transmitting schistosomes.

Interactions between Schistosoma haematobium group species and their Bulinus spp. intermediate hosts along the Niger River Valley.

Background: Urogenital schistosomiasis, caused by infection with Schistosoma haematobium, is endemic in Niger but complicated by the presence of Schistosoma bovis, Schistosoma curassoni and S. haematobium group hybrids along with various Bulinus snail intermediate host species. Establishing the schistosomes and snails involved in transmission aids disease surveillance whilst providing insights into snail-schistosome interactions/compatibilities and biology.

Parasite Population Genetic Contributions to the Schistosomiasis Consortium for Operational Research and Evaluation within Sub-Saharan Africa.

Analyses of the population genetic structure of schistosomes under the "Schistosomiasis Consortium for Operational Research and Evaluation" (SCORE) contrasting treatment pressure scenarios in Tanzania, Niger, and Zanzibar were performed to provide supplementary critical information with which to evaluate the impact of these large-scale control activities and guide how activities could be adjusted. We predicted that population genetic analyses would reveal information on a range of important parameters including, but not exclusive to, recruitment and transmission of genotypes, occurrence of hybridization events, differences in reproductive mode, and degrees of inbreeding, and hence, the evolutionary potential, and responses of parasite populations under contrasting treatment pressures. Key findings revealed that naturally high levels of gene flow and mixing of the parasite populations between neighboring sites were likely to dilute any effects imposed by the SCORE treatment arms.

Snail-Related Contributions from the Schistosomiasis Consortium for Operational Research and Evaluation Program Including Xenomonitoring, Focal Mollusciciding, Biological Control, and Modeling.

The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) was created in 2008 to answer questions of importance to program managers working to reduce the burden of schistosomiasis in Africa. In the past, intermediate host snail monitoring and control was an important part of integrated schistosomiasis control. However, in Africa, efforts to control snails have declined dramatically over the last 30 years.

Development of a recombinase polymerase amplification (RPA) fluorescence assay for the detection of Schistosoma haematobium.

Background: Accurate diagnosis of urogenital schistosomiasis is vital for surveillance and control programmes. While a number of diagnostic techniques are available there is a need for simple, rapid and highly sensitive point-of-need (PON) tests in areas where infection prevalence and intensity are low. Recombinase Polymerase Amplification (RPA) is a sensitive isothermal molecular diagnostic technology that is rapid, portable and has been used at the PON for several pathogens.

Freshwater snails of biomedical importance in the Niger River Valley: evidence of temporal and spatial patterns in abundance, distribution and infection with Schistosoma spp.

Background: Sound knowledge of the abundance and distribution of intermediate host snails is key to understanding schistosomiasis transmission and to inform effective interventions in endemic areas.

Methods: A longitudinal field survey of freshwater snails of biomedical importance was undertaken in the Niger River Valley (NRV) between July 2011 and January 2016, targeting Bulinus spp. and Biomphalaria pfeifferi (intermediate hosts of Schistosoma spp.

Occurrence of Schistosoma bovis on Pemba Island, Zanzibar: implications for urogenital schistosomiasis transmission monitoring.

The causative agent of urogenital schistosomiasis, Schistosoma haematobium, was thought to be the only schistosome species transmitted through Bulinus snails on Unguja and Pemba Island (Zanzibar, United Republic of Tanzania). For insights into the environmental risk of S. haematobium transmission on Pemba Island, malacological surveys collecting Bulinus globosus and B.

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.

Urogenital schistosomiasis transmission on Unguja Island, Zanzibar: characterisation of persistent hot-spots.

Background: Elimination of urogenital schistosomiasis transmission is a priority for the Zanzibar Ministry of Health. Preventative chemotherapy together with additional control interventions have successfully alleviated much of the disease burden. However, a persistently high Schistosoma haematobium prevalence is found in certain areas.