Urogenital Schistosomiasis Transmission Research Articles

Exploring the Adaptation of Bulinus senegalensis and Bulinus umbilicatus to the Dry and Rainy Season in Ephemeral Pond in Niakhar (Senegal), an Area of Seasonal Transmission of Urogenital Schistosomiasis

Exploring the Adaptation of Bulinus senegalensis and Bulinus umbilicatus to the Dry and Rainy Season in Ephemeral Pond in Niakhar (Senegal), an Area of Seasonal Transmission of Urogenital Schistosomiasis

Experimental Infections Reveal Acquired Zoonotic Capacity of Human Schistosomiasis Trough Hybridization.

We are currently witnessing the endemization of urogenital schistosomiasis in southern Europe. The incriminated parasite is a hybrid between a human parasite and a livestock parasite. Using an experimental evolutionary protocol, we created hybrid lines from pure strains of both parasite species. We showed that the host spectrum of the human parasite is enlarged to the livestock parasite after genomic introgression. We also evidenced that the tropism of the parasites within the host changes and that some hybrid lines are more virulent than the parental strains. These results engage a paradigm shift from human to zoonotic transmission of urogenital schistosomiasis.

An accident waiting to happen? Exposing the potential of urogenital schistosomiasis transmission in the Lake Albert region, Uganda

BackgroundUrogenital schistosomiasis caused by the parasitic blood fluke Schistosoma haematobium is the most common form of that constitutes a majority of over 240 million schistosomiasis cases. The enigmatic absence of urogenital schistosomiasis in Uganda has, until now, been attributed to the absence of substantial populations of suitable snail intermediate hosts.MethodsMalacological surveys were carried out in 73 sites southeast of Lake Albert, Uganda in October and November 2020. Collected snails were transported to the laboratory for identification. The snails were identified using partial mitochondrial cytochrome c oxidase subunit one and nuclear internal transcribed spacer barcoding. Schistosome infections in snails were also assessed using cercarial shedding and rapid diagnostic PCR techniques.ResultsWe found Bulinus globosus and Bulinus nasutus productus, the main intermediate species in the transmission of S. haematobium in mainland East Africa. In this survey, B. globosus was more common than B. nasutus productus, with the former reported at four sites (total count = 188) and the latter reported at one site (total count = 79). Molecular testing revealed a high prevalence of Schistosoma bovis in B. nasutus productus (16%), but no S. haematobium infections were found.ConclusionsGiven the abundance of snail hosts and the risky human water contact behaviours observed, we highlight the potential for urogenital schistosomiasis transmission in the region.Graphical

Prevalence and factors associated with ongoing transmission of Schistosoma haematobium after 12 rounds of Praziquantel Mass Drug Administration among school age children in Southern Tanzania

BackgroundWorld Health Organization (WHO) recommends periodic praziquantel Mass Drug Administration (MDA) to vulnerable populations, especially school-aged children, to reduce the risk of transmission. In the S. haematobium endemic Lindi region, on the southeastern coast of Tanzania, praziquantel has been distributed for more than a decade (12 rounds) in schools. However, there is a paucity of data on the current burden and factors perpetuating ongoing urogenital schistosomiasis among SAC. The study investigated the prevalence and factors associated with the ongoing transmission of S. haematobium among school-age children (SAC) after 12 rounds of praziquantel in Nachingwea, Southern Tanzania. Material and methodsA quantitative cross-sectional study was conducted between May and June 2022 among 483 SAC in the Nachingwea district. Macrohematuria, microhaematuria, and S. haematobium eggs were assessed in the collected urine sample for each participant, using macroscopic observation, urine dipstick, and urine filtration techniques, respectively. Infection intensity was quantified for positive S. haematobium urine samples. Knowledge and attitudes towards schistosomiasis were assessed among participants through an interview-administered questionnaire, and water contact practices were registered through an observation checklist. Data were summarized using descriptive statistics, the Chi-square test, and logistic regression. ResultsThe prevalence of S. haematobium infection was 10.6%, with 0.6% (3/51) prevalence of heavy infection. The factors associated with S. haematobium persistence transmission were a habit of visiting the water bodies (AOR = 1.62, 95% CI: 0.40–1.96), swimming in the visited water bodies (AOR = 4.58, 95% CI: 1.72–12.19), using water from the river source (AOR = 3.79, 95% CI: 1.51–9.51) and attending Mkumba Primary School (17.4%; AOR = 6.12, 95% CI: 1.64–22.85). ConclusionsFindings suggest ongoing transmission of urogenital schistosomiasis in the Nachingwea District despite 12 rounds of praziquantel treatment, with a low prevalence of heavy infection (0.6%). Praziquantel distribution should be complemented with health education, especially on the cause and transmission of urogenital schistosomiasis to increase knowledge that will improve a good attitude towards schistosomiasis prevention. An adequate water supply is to be considered to reduce infections due to the visit to water sources for daily use.

Parasitic and Ecological Factors Associated with Transmission of Urogenital Schistosomiasis in Owena Reservoir Area, Ondo State, Nigeria

Human urogenital schistosomiasis caused by infection of the trematode worm Schistosoma hematobium is a major source of morbidity and mortality in Ondo State especially in Owena Reservoir Area, Ondo East Local Government Area, Ondo State, Nigeria. The aim of this study was to investigate: (i) the seasonal and spatial distribution, infection and cercariae shedding patterns of identified local Schistosoma intermediate snail host(s); (ii) to determine the influence of ecological factors on the identified intermediate snail species in the transmission of urogenital schistosomiasis along the Owena Reservoir and river courses. All the snails collected were placed in pre-labeled plastic containers and were transported to a Malacology Laboratory at Ile-Ife, Osun State, Nigeria. The snails were identified to species level, counted and recorded as number of snails, per site, per date. The snails were identified using standard identification keys. Examination of snails for Schistosoma infection was carried out by crushing method. Cercariae were identified to genus level. However, only snails shedding Schistosoma cercariae were recorded as infected. Each of the eight sites was sampled once monthly for twenty-four months. Eight stations (sites) of diverse ecological characteristics were selected along the Owena Reservoir and monitored for snails species’ diversity, distribution and infection patterns, physicochemical properties of H2O, macrophyte types and coverage in relation to the transmission of urogenital schistosomiasis. Seven snail species representing two sub-classes, three families and five genera were identified in Owena Reservoir Area. Bulinus globosus and Bulinus truncatus were the only established Schistosoma intermediate snail hosts in site 4 (KAJ 1) located in Kajola community. Out of the eight sites studied, site 4 in Kajola community had the highest infection rate while Embankment/Dam (site 8) had the least. Site 4 in Kajola community is therefore the major transmission site. All the snail species correlated positively with alkalinity conduction, negatively with air temperature. Bulinus globosus correlated significantly positive with Ludwiga erecta, Ludwiga decurrens, Commelina africana, and Berberis calamus (p<0.05) but correlated significantly negative with Panicum maximus and Ervatomia hirta (p>0.05). Bulinus truncatus correlated significantly positive with Aspillia africana, Ludwiga decurrens, Emilia occinina, and Crosus sativue (p<0.05) but correlated significantly negative with Ludwiga erecta, Panicum maximus, and Commelina africana (p>0.05). This study recommends environmental management and manipulation using water level regulations to render water contact sites environmentally unfriendly for both snail growth and human recreational activities during the period of high risk transmission since chemical control (the use of molluscicide) poses a risk to health, not only to the snail intermediate hosts but also to the inhabitants of the communities who commonly depend on reservoirs, streams, rivers, dams for their domestic water supply.

Urogenital Schistosomiasis Transmission and Human Water Contact Activities in Owena Reservoir/Dam, Ondo East Local Government Area, Ondo State, Nigeria

<i>Background</i>: This study on urogenital schistosomiasis transmission and the roles played by human water contact activities was carried out in selected three communities viz Owena, Kajola and Baiken, bordering Owena Reservoir/Dam in Ondo East Local Government Area, Ondo State, Nigeria for a period of twenty four months. <i>Objective</i>: To ascertain the effects of human water contact activities on urogenital schistosomiasis transmission. <i>Materials and Methods</i>: Each site was observed for water contact activities once every month for twenty-four months. Observation was made at each site in February (dry season), May (early rainy season), August (rainy season) and November (early dry season). During this period, records were taken about individuals entering and leaving the water. Various types of human water contact activities were grouped on the basis of general purpose of contact. With regards to degree of body exposure and mean duration of contacts; using canoe, fetching water, washing household utensils, sorting fish and washing exposed limbs, all involved exposure of only parts of the lower limbs (foot and leg) and or the upper limbs (hand and forearm) for a brief period of time grouped as partial contact activities. Water contact activities consist of washing clothes and fish nets, processing food products (such as cassava and palm oil) may involve exposure of most parts of the lower and/or the upper limbs for a longer period. Swimming and bathing commonly involve total exposure for a very long time and were designated as complete contacts. <i>Results</i>: General pattern of human water contact activities in the study revealed 34,686 (61.6%) domestic, 15,897 (28.2%) economic, 5,732 (10.2%) recreational and 15 (0.03%) religious activities. Frequency of these activities varied significantly (p<0.05) among stations and seasons but comparable from one year to the other. School children (5-19 years age group) spent more time on exposure than adults who spent more time on partial and limited exposure. As a result, the exposure index was significantly (p<0.001) age dependent and followed the same pattern as duration of contact. Site containing most infected <i>Bulinus globosus </i>snails was site 4 (KAJ 1) at Kajola community with snail infection rate of 9.2% and the same site 4 (KAJ 1) had the highest relative index of exposure (15,063.80) as well as level of total duration (14,215) of contact in minutes. <i>Conclusion</i>: Site 4 (KAJ 1) at Kajola community was the transmission site in Owena Reservoir/Dam, Ondo East Local Government Area, Ondo State, Nigeria.

Bulinus snails in the Lake Victoria Basin in Kenya: Systematics and their role as hosts for schistosomes.

The planorbid gastropod genus Bulinus consists of 38 species that vary in their ability to vector Schistosoma haematobium (the causative agent of human urogenital schistosomiasis), other Schistosoma species, and non-schistosome trematodes. Relying on sequence-based identifications of bulinids (partial cox1 and 16S) and Schistosoma (cox1 and ITS), we examined Bulinus species in the Lake Victoria Basin in Kenya for naturally acquired infections with Schistosoma species. We collected 6,133 bulinids from 11 sites between 2014-2021, 226 (3.7%) of which harbored Schistosoma infections. We found 4 Bulinus taxa from Lake Victoria (B. truncatus, B. tropicus, B. ugandae, and B. cf. transversalis), and an additional 4 from other habitats (B. globosus, B. productus, B. forskalii, and B. scalaris). S. haematobium infections were found in B. globosus and B. productus (with infections in the former predominating) whereas S. bovis infections were identified in B. globosus, B. productus, B. forskalii, and B. ugandae. No nuclear/mitochondrial discordance potentially indicative of S. haematobium/S. bovis hybridization was detected. We highlight the presence of Bulinus ugandae as a distinct lake-dwelling taxon closely related to B. globosus yet, unlike all other members of the B. africanus species group, is likely not a vector for S. haematobium, though it does exhibit susceptibility to S. bovis. Other lake-dwelling bulinids also lacked S. haematobium infections, supporting the possibility that they all lack compatibility with local S. haematobium, thereby preventing widespread transmission of urogenital schistosomiasis in the lake's waters. We support B. productus as a distinct species from B. nasutus, B. scalaris as distinct from B. forskalii, and add further evidence for a B. globosus species complex with three lineages represented in Kenya alone. This study serves as an essential prelude for investigating why these patterns in compatibility exist and whether the underlying biological mechanisms may be exploited for the purpose of limiting schistosome transmission.

Attitude, Knowledge, Perception, Behavioural, Cultural and Religious Practices Influencing Transmission of Urogenital Schistosomiasis in Owena, Kajola and Baiken Communities Bordering Owena Reservoir/Dam, Ondo East Local Government Area, Ondo State, Nigeria

Background: Human urogenital schistosomiasis remains an important public health problem in Nigeria, especially in three communities, Owena, Kajola and Baiken bordering Owena Reservoir/Dam, Ondo East Local Government Area, Ondo State, Nigeria. Unfortunately, scientific-based facts about attitude, knowledge, perception, behavioural, cultural and religious practices influencing the transmission of urogenital schistosomiasis are grossly scanty and without which sustainable control strategies cannot be planned. The aim of the study was to identify the roles played by the aforementioned variables in the transmission of the disease with a view to fashioning out sustainable control strategies of the disease. Materials and Methods: A structured questionnaire was used to collect basic information on personal biodata, perception, health history, etc from the subjects. Data obtained were analyzed using Chi-square test, Analysis of variance (ANOVA) and correlation analysis. Results: Summary of significant associations between knowledge and socio-demographic characteristics of the three communities combined showed the following: gender status (p&lt;0.000), distribution of latrine facilities in the communities (p&lt;0.000), ignorance of how urogenital schistosomiasis is transmitted (p&lt;0.002), self-medication urogenital schistosomiasis treatment (p&lt;0.000), frequency of visits to the reservoir (p&lt;0.001) (see Table I). Further results of this study revealed that participants’ perception, behavioural, cultural, religious practices were not significantly associated with the danger of urogenital schistosomiasis (p&lt;0.110), snails seen around reservoir (p&lt;0.259), reservoir ever visited before (p&lt;0.24), household having toilet facilities (p&lt;0.32), blood passed in urine (p&lt;0.86), treatment ever received for urogenital schistosomiasis infection (p&lt;0.86) (see Table III). Conclusion: The overall findings of this twenty-four-month (August 2013 – July 2015) study showed that people orientations such as attitude, knowledge, perception, behavioural, cultural, religious practices about the causal factors, transmission cycles, negative impacts of urogenital schistosomiasis are grossly scanty and these could pose a threat to sound intervention strategies of the control of the disease. Control strategies should involve mass sensitization focused on health education, and on transmission to emphasise the role commonly played by water contact activities. Frequency of occurrence of snails’ host and urination habits should be looked into, as well. Enlightening teachers, parents to control the water contact behaviour of their wards especially the age group 5-15 years which accounts for 52% of total index of exposure. Adequate provision of modern alternative sources of water supply (e.g. pipe-borne water) with a view to reducing the population index of exposure, should be encouraged.

Urogenital schistosomiasis: prevalence, knowledge and practices among women of reproductive age in Northern Tanzania

To determine the prevalence, knowledge and practices regarding urogenital schistosomiasis among women of reproductive age in Kileo Ward, Mwanga District. A cross-sectional study was conducted in the dispensary in Kileo Village, Mwanga District. A pre-tested structured questionnaire was administered to participants to collect information on sociodemographic characteristics and schistosomiasis-related knowledge and practices. Urine samples were examined for schistosoma eggs using the urine sedimentation technique. Data collected were cleaned, coded and entered into SPSS Version 20 for analysis. Chi-squared test and Fisher's exact test were used for analysis. Overall prevalence of urogenital schistosomiasis was 2.3%. The prevalence was higher among participants aged ≥18 years (3.2%), those who did domestic chores in river water (13.3%), and those who swam in river water (7.1%). Only a few participants had a low level of knowledge (4.8%) and poor practices (1.9%) regarding urogenital schistosomiasis. The transmission of urogenital schistosomiasis was low among women of reproductive age in the study area. Despite a high level of knowledge and good practices for urogenital schistosomiasis, there are knowledge gaps regarding its causes and risk factors.

Urogenital schistosomiasis transmission, malaria and anemia among school-age children in Northern Ghana

BackgroundIn sub-Saharan Africa, co-morbidity with malaria, schistosomiasis, and soil transmitted helminths (STH) is common among young children. The current study investigated malaria, urinary schistosomiasis and their co-infection and anemia among school-age children in an endemic community, Nakolo in the Kassena-Nankana East District of northern Ghana. MethodsA cross-sectional survey of 336 school-age children, 5–16 years was undertaken. Urine samples were examined for Schistosoma haematobium ova using microscopy. Finger prick blood samples were examined for Plasmodium parasites using microscopy and haemoglobin concentration measured with HemoCue Hb301 photometer. ResultsThe mean age was 10.52 (Standard deviation: ±2.27; range: 5–16 years), of which 50.6% (170/336) were males. The overall prevalence of urinary schistosomiasis and Plasmodium (P.) falciparum was 12.8% (43/336) and 37.8% (127/336), respectively with 6.0% (20/336) coinfection. Participants with only P. falciparum infection had 17.8% (19/107) of moderate anemia whilst 21.7% (5/23) of children infected with only S. haematobium had moderate anemia and 4.3% (1/23) had severe anemia. 5.0 % (1/20) of moderate anemia was observed in concurrent infections of P. falciparum and S. haematobium. Use of open water bodies was associated with increased risk of S. haematobium infection (OR = 1.21; 95% CI = [1.06–1.39]; p = 0.001), with females being at reduced risk (OR = 0.93; 95%CI = [0.87–0.99]; p = 0.005). Absence of self-reported haematuria had 0.81 times reduced odds of S. haematobium infection (OR = 0.81; 95%CI = [0.74–0.87]; p < 0.001). ConclusionThis study has revealed that urinary schistosomiasis remains prevalent in Kassena-Nankana East district and suggests that urinary schistosomiasis may contribute to moderate anemia among school-age children as compared to asymptomatic malaria infection. These findings call for an evaluation of the annual mass drug administration of Praziquantel among in-school children to ascertain its impact on urinary schistosomiasis prevalence across the district.

Urogenital schistosomiasis prevalence, knowledge, practices and compliance to MDA among school-age children in an endemic district, southern East Tanzania

BackgroundTanzania has a high prevalence of urogenital schistosomiasis. Praziquantel is administered to school-age children on an annual basis as part of efforts to reduce transmission and morbidity associated with heavy infections. We investigated the prevalence, knowledge, and practices of urogenital schistosomiasis transmission, as well as compliance with mass drug administration (MDA) among schoolchildren in Masasi District. Materials and methodsA cross-sectional survey was conducted in five primary schools. A pre-tested questionnaire was used to assess knowledge and practice related to the transmission of urogenital schistosomiasis, as well as compliance with MDA. Collected urine samples were examined macroscopically for macrohematuria. They were then tested for microhematuria and Schistosoma haematobium (S. haematobium) eggs with urine dipsticks and filtration technique, respectively. FindingsThe study included 389 primary school children in total. Overall, 27 (6.9%) of children had S. haematobium infection, and 37 (9.5%) had microhematuria. The mean (SD) intensity was 123.4 (247.4) eggs per 10 ml of urine. A total of 10 (2.6%) had heavy intensity of infection. The majority (94.9%) reported having complied to the previous round of MDA six months prior to this study, and 308 (79.2%) were aware that water contact is associated with an increased risk of urogenital schistosomiasis infection. Nevertheless, 182 (46.8%) of the participants engaged in swimming activities, with 92 (50.9%) of the participants being female. The prevalence of urogenital schistosomiasis was higher (10.9%) among children who participated in swimming activities versus those who did not (3.4%) (P = 0.003). ConclusionDespite high MDA compliance, urogenital schistosomiasis is still prevalent among primary school children in Masasi District. Children who swim in freshwater bodies such as rivers and ponds are more likely to contract urogenital schistosomiasis.

Leave No Preschool-Aged Children Behind: Urogenital Schistosomiasis in Four Communities of a Metropolitan City in Central Nigeria

There have been several demands for preschool-aged children to get prophylactic chemotherapy, such as praziquantel, first due to a presumed schistosomiasis among this age group. In order to determine the prevalence and risk variables related to urogenital schistosomiasis infection among preschool-aged children, this study conducted surveys in four areas inside a major city in Central Nigeria. A total of 240 preschool-aged children were randomly selected from the four areas surveyed. Demographic data and their knowledge on the transmission of urogenital schistosomiasis were obtained by administering questionnaire to mothers and caregivers, urine samples of the recruited subjects were collected using a sterile sampling bottles and were tested for hematuria using Urino-Combi-11 reagent test strip (ACON laboratories). Subsequently, samples were screened in the laboratory for Schistosoma haematobium infection. Of the 235 preschool-aged children that returned their sample bottles, only 8.51% (20/235) were infected with urogenital schistosomiasis. Four years old subjects were the most infected 13.95% (6/43) followed by age two 10.56% (2/19) then age five with 8.93% (10/112), age three 3.70% (2/54) while no age one child was infected 0% (0/7), although variations in prevalence across the ages showed no significant difference (P˃0.05). The overall geometric mean intensity (GMI) was 1.03526 eggs/10ml of urine. The prevalence of the infection among preschool-aged children in relation to locations as well as sex showed no significant difference (P˃0.05). About 52% (122) of the preschool-aged children bath in water bodies, but only 51.1% (120) are aware that some freshwater snails are harmful. In conclusion, preschool-aged children in the metropolitan city of Lafia should not bath, wash or swim in water bodies around. More awareness should be created on the risk factors associated with the disease. Also, the government should provide sufficient potable water in the city, and prioritization of treatment of preschool-aged children with preventive chemotherapy to curb urogenital schistosomiasis prevalence among the age group is very necessary and cannot be overemphasized.

Evidence of autochthonous transmission of urinary schistosomiasis in Almeria (southeast Spain): An outbreak analysis

BackgroundSchistosomiasis is endemic in 78 countries belonging to tropical and subtropical areas. However, autochthonous transmission of urogenital schistosomiasis was reported in Corsica (France) in 2013. We present evidence of autochthonous transmission of urogenital schistosomiasis in Almería (Spain) in 2003. MethodsDescription of the outbreak in farmers and subsequent epidemiological studies aimed at searching for Bulinus snails and their genotypic characteristics. ResultsThe outbreak affected 4 farmers out of a group of 5 people who repeatedly bathed that summer in an irrigation pool in the area. Two of them presented macroscopic hematuria with bilharziomas, showing the presence of Schistosoma eggs in bladder biopsies. Two others were asymptomatic but the serology for schistosomiasis was positive. In 2015, the presence of the vector Bulinus truncatus was demonstrated in Almería in water collections of appropriate characteristics. DNA sequencing proving that local B. truncatus species were base-to-base identical to B. truncatus from Senegal. ConclusionsWe present a new outbreak of autochthonous transmission of urogenital schistosomiasis in Europe. Although no new cases of autochthonous transmission have been reported, some other cases may have occurred at that time or later on and be unnoticed as many cases of schistosomiasis are asymptomatic or present mild and unspecific symptoms.

Prevalence of Urogenital Schistosomiasis and Risk factors for transmission among Primary School Children in an endemic urban area of Kinondoni municipality in Dar es Salaam, Tanzania

Background: Schistosomiasis is among the neglected tropical diseases that cause significant morbidity and mortality among the vulnerable population including school-aged children. This study aimed to determine the prevalence of urogenital schistosomiasis and risk factors for transmission among primary school children in an endemic urban area of Kinondoni municipality in Dar es Salaam, Tanzania. Methods: A quantitative cross-sectional study was conducted between June and August 2020. A total of 250 urine samples were collected from primary school children, examined for haematuria using urinalysis test strips, and Schistosoma haematobium (S.haematobium) infection and intensity using the urine filtration technique. A structured questionnaire was used to collect information on water, sanitation, and hygiene risk factors that could influence the transmission of urogenital schistosomiasis. Results: Out of 250 primary school children recruited, 13(5.2%) had haematuria, 3(1.2%) had S.haematobium ova, and all were light-intensity infections. Among the assessed risk factors, the following were significantly associated with the transmission of urogenital schistosomiasis; type of latrine used at home (p=0.044), frequency of swimming (p=0.030), the children who never swallowed praziquantel (p < 0.00), experienced side effects (p < 0.00), type of side effects experienced (p=0.037), and reasons for not taking praziquantel in the last round of mass drug administration (p=0.007). Conclusion: The low prevalence of urogenital schistosomiasis indicates the ongoing transmission of the disease among primary school children. Frequency of swimming, type of latrines used at home, and non-uptake of praziquantel are the risk factors for the infection among primary school children.

SCORE Operational Research on Moving toward Interruption of Schistosomiasis Transmission.

.As part of its diverse portfolio, the Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) included two cluster-randomized trials evaluating interventions that could potentially lead to interruption of schistosomiasis transmission (elimination) in areas of Africa with low prevalence and intensity of infection. These studies, conducted in Zanzibar and Côte d’Ivoire, demonstrated that multiyear mass drug administration (MDA) with praziquantel failed to interrupt the transmission of urogenital schistosomiasis, even when provided biannually and/or supplemented by small-scale implementation of additional interventions. Other SCORE activities related to elimination included a feasibility and acceptability assessment of test–treat–track–test–treat (T5) strategies and mathematical modeling. Future evaluations of interventions to eliminate schistosomiasis should recognize the difficulties inherent in conducting randomized controlled trials on elimination and in measuring small changes where baseline prevalence is low. Highly sensitive and specific diagnostic tests for use in very low–prevalence areas for schistosomiasis are not routinely available, which complicates accurate measurement of infection rates and assessment of changes resulting from interventions in these settings. Although not encountered in these two studies, as prevalence and intensity decrease, political and community commitment to population-wide MDA may decrease. Because of this potential problem, SCORE developed and funded the T5 strategy implemented in Egypt, Kenya, and Tanzania. It is likely that focal MDA campaigns, along with more targeted approaches, including a T5 strategy and snail control, will need to be supplemented with the provision of clean water and sanitation and behavior change communications to achieve interruption of schistosome transmission.

Molecular diversity of Bulinus species in Madziwa area, Shamva district in Zimbabwe: implications for urogenital schistosomiasis transmission

BackgroundBulinus species are freshwater snails that transmit the parasitic trematode Schistosoma haematobium. Despite their importance, the diversity of these intermediate host snails and their evolutionary history is still unclear in Zimbabwe. Bulinus globosus and B. truncatus collected from a urogenital schistosomiasis endemic region in the Madziwa area of Zimbabwe were characterized using molecular methods.MethodsMalacological survey sites were mapped and snails were collected from water contact sites in four communities in the Madziwa area, Shamva district for a period of one year, at three-month intervals. Schistosoma haematobium infections in snails were determined by cercarial shedding and the partial mitochondrial cytochrome c oxidase subunit 1 gene (cox1) was used to investigate the phylogeny and genetic variability of the Bulinus spp. collected.ResultsAmong the 1570 Bulinus spp. snails collected, 30 (1.9%) B. globosus were shedding morphologically identified schistosomes. None of the B. truncatus snails were shedding. The mitochondrial cox1 data from 166 and 16 samples for B. globosus and B. truncatus, respectively, showed genetically diverse populations within the two species. Twelve cox1 haplotypes were found from the 166 B. globosus samples and three from the 16 B. truncatus samples with phylogenetic analysis showing that the haplotypes fall into well-supported clusters within their species groups. Both B. truncatus and B. globosus clustered into two distinct lineages. Overall, significant negative values for both Tajima’s D statistic and the Fu’s Fs statistic were observed for B. globosus and B. truncatus.ConclusionsThe study provided new insights into the levels of genetic diversity within B. globosus and additional information on B. truncatus collected from a small geographical area in Zimbabwe. Low prevalence levels of infection observed in the snails may reflect the low transmission level of urogenital schistosomiasis in the area. Our results contribute towards the understanding of the distribution and population genetic structure of Bulinus spp. supporting the mapping of the transmission or risk of transmission of urogenital schistosomiasis, particularly in Zimbabwe.

Risk map of transmission of urogenital schistosomiasis by Bulinus truncatus (Audouin, 1827) (Mollusca Gastropoda, Bulinidae) in Spain and Portugal

We present a geographical distribution map of Bulinus truncatus based on historical and current localities in Spain and Portugal, that corresponds to the risk map of urogenital schistosomiasis for this freshwater snail. We reviewed samples of the species deposited at the Museu de Ciències Naturals of Barcelona and the Museo Nacional de Ciencias Naturales of Madrid, together with our own data, including some unpublished contributions. This map will help determine the optimal area for this species and identify areas of greatest risk for urogenital schistosomiasis in the two countries. We emphasize that global change and climate change may favour the presence of both the vector (B. truncatus) and the parasite (Schistosoma haematobium) in Spain and Portugal.

Transmission Dynamics of Urogenital Schistosomiasis in the Rural Community of Ebonyi State, South Eastern Nigeria.

This study accessed the dynamics of urogenital schistosomiasis transmission in Nkalagu Community. A total of 500 mid-day urine samples were collected and transported to Microbiology Laboratory, Ebonyi State University, for analysis. 10ml each of the urine samples was centrifuged at 2500 rpm for 5 minutes. Transmission potential of snail intermediate host of Schistosomes collected from different sampling station at the transmission sites within the study community was equally accessed. The snail species collected were placed individually into a clean beaker with little quantity of water and then subjected to shedding light for 2 hours. Data obtained were entered in excel spread sheet and analyzed using chi square test. The result obtained shows that 205 (41%) out of 500 individuals examined were excreting S. haematobium ova in their urine. The highest prevalence of infection (23%) was found among 11-20-year age groups. Males were more infected (25.4%) than their female counterparts (15.6%), although this was not statistically significant (p > 0.05). A total of 283 snails belonging to two Bulinus species (B. globosus and B. truncatus) were collected from the four sites sampled. Bulinus globosus recorded the highest species abundance (177) with the highest occurrence in site A. 52 (18.4%) out of 283 snails collected were infected with cercariae, and the highest cercariae infection (12.0%) was recorded among B. globosus. With prevalence of 41% among the human population and the prevalence of 18.4% patent infection among the snail intermediate hosts, urogenital schistosomiasis is still a public health problem in the study area and falls within the WHO classification of endemic area. Public health campaign is recommended in order to educate the people on the mode of transmission and control of the disease.

Geographical and behavioral risks associated with Schistosoma haematobium infection in an area of complex transmission

BackgroundSchistosoma haematobium infection in endemic areas varies depending on the nature and complexity of the transmission networks present. Studies of micro-geographical transmission of S. haematobium infection indicate that discrepancy in prevalence between households is associated with diverse water contact behaviors and transmission that is restricted to particular sites harboring snail intermediate hosts. Detection of variations in the transmission sources with complex transmission networks of water bodies is required for optimization of malacological control. Longitudinal parasitological and malacological surveys were conducted to investigate geographical variations in transmission of urogenital schistosomiasis in Ikingwamanoti village, Shinyanga District, Tanzania.MethodsUrine samples were collected at baseline and follow-up time points from 282 school-aged children and examined microscopically for the presence of S. haematobium eggs. Malacological surveys involved collection of Bulinus nasutus every month from 30 sites. Snails were examined for patent infections. Global positioning system was used to map household distances from S. haematobium transmission sites, while water contact behavior was assessed using a questionnaire.ResultsSchistosoma haematobium infection was observed to be prevalent among older children (12–14 years) compared to younger groups prior to treatment, but no significant difference in infection prevalence was observed at one-year. Boys were highly infected than girls at both time points. No spatial influence was observed between children’s infection and the distance from child’s residence to the nearby snail habitats nor was any significant association observed between children’s reported water contact behavior with S. haematobium infection. However, malacological surveys with cercarial shedding combined with GPS data detected significant variation among different water sources in the transmission of S. haematobium with children living in households near to ponds with high B. nasutus populations having the highest prevalence of infection.ConclusionsInteraction between malacological surveys with cercarial shedding combined with GPS mapping in endemic settings can help detection of transmission sources even in areas with complex transmission networks. Subsequent studies are needed to determine whether the combination of GPS mapping and parasitology screens can aid the detection of transmission hotspots across varied transmission settings to enhance schistosomiasis control programmes.

A persistent risk of urogenital schistosomiasis transmission linked to the Cavu River in Southern Corsica since 2013

Introduction Urogenital schistosomiasis, a tropical snail-borne disease, re-emerged in Europe in 2013, with 106 cases linked to exposure to the Cavu River in Southern Corsica. The implicated parasite strain was a hybrid of a human-bovine Schistosoma parasite (S. haematobium–S. bovis) of Senegalese origin. The parasite's introduction to the river was presumed to have occurred via an infected individual. Subsequent to this outbreak, we developed a human and snail surveillance system to detect and control schistosomal transmission. Environmental research and phylogenetic analysis were performed to understand the continuing transmission of schistosomiasis in the river. Methods Autochthonous urogenital schistosomiasis became a notifiable disease in France from 2016. A case was defined as a person with serological or parasitological evidence of schistosomiasis, with no history of travel outside of Corsica in a known endemic area. Patient specimens were genotyped, and compared with the 2013 outbreak strain. Seasonal molecular surveillance of snails in the Cavu River was established for rapid detection of schistosomes. Bulinus truncatus snails, intermediates host of S. haematobium, are collected weekly from the Cavu River when conditions are optimal for schistosomal transmission (June–September). Seroprevalence studies in livestock in Southern Corsica and in wild rodents captured along the Cavu River, were conducted. Results Following the 2013 outbreak, seven new cases were identified: one in 2015, four in 2016 and two in 2017. Three cases reported exposure to the Cavu River in summer 2015, two cases in both summer 2015 and 2016 and two other cases in 2016 and 2017. For the last cases, the period between the 2017 exposure and the diagnosis of the symptomatic case is of four weeks whereas the average time for onset of symptoms after exposure is of 30 weeks. Therefore, this suggests that the infection occurred in 2016. Although no specimen was isolated from patients exposed only in 2015, specimens from a patient exposed in 2015/2016 and from another patient exposed in 2016/2017 were closely related to the 2013 strain. With between 1965 and 5364 snails analyzed each year, the surveillance did not detect any Schistosoma-infested snails in the river from 2015 to 2017. Twenty-one rodents were captured for testing along the river and 3,479 cows and goats in Southern Corsica. All seroprevalence tests were negative. Discussion/Conclusion Corsica possesses all the necessary conditions for permanent transmission of urogenital schistosomiasis. Further research on the survival of infested snails over the winter period, and on the presence of a rodent reservoir in the river area are fundamental to evaluate the risk of ongoing transmission of urogenital schistosomiasis in the Cavu River. The persistence of a human reservoir in vicinity of the Cavu River would increase this risk. Therefore, tourists and locals exposed to the river must be advised of the risk of recreational water use in the Cavu. Public health authorities must reinforce physicians’ awareness of screening recommendations, to promptly detect and treat new cases and to prevent further transmission in Corsica. The maintenance of schistosomes in Corsica serves as a warning to other regions in Europe with environmental conditions favorable to urogenital schistosomiasis transmission.