Factors affecting the intensity of reinfection with Schistosoma haematobium following treatment with praziquantel

Parasitology ◽  
1991 ◽  
Vol 102 (1) ◽  
pp. 73-83 ◽  
Author(s):  
S. K. Chandiwana ◽  
M. E. J. Woolhouse ◽  
M. Bradley
Keyword(s):  
Rural Community ◽  
Schistosoma Haematobium ◽  
Time Of Day ◽  
Reinfection Rate ◽  
Water Contact ◽  
Factors Affecting ◽  
Quantitative Estimates ◽  
Index Of Exposure ◽  
Bulinus Globosus ◽  
Independent Effects

SUMMARYInfection with Schistosoma haematobium was studied in a rural community of approximately 500 persons in eastern Zimbabwe. The overall prevalence of infection, as determined by urine egg counts, was 40·1%, and of heavy infections (≥ 50 eggs/10 ml urine) was 11·0%. The prevalence of both heavy and all infections was highest in the 8 to 10-year-old age class. During 1987–88 data were obtained from 102 individuals on intensity of reinfection 14 weeks after treatment with praziquantel, the efficacy of treatment having been determined after 4 weeks. The water contact made by these individuals during 2-week periods immediately following treatment was recorded. The relative abundance of patent infected intermediate host snails, Bulinus globosus, was also monitored. An index of exposure was developed which weighted each water contact by its duration, the type of activity, the time of day, and the abundance of infected snails at the site used. The relationships between rates of reinfection, rates of exposure, and age were examined. Although only 13 individuals showed positive rates of reinfection, there were statistically significant and independent effects of both exposure and age on reinfection rate. Quantitative estimates of reinfection rates suggested that individuals aged 12 years or less acquired substantially more infection (measured as egg output) than individuals more than 12 years old.

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

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Masceline Jenipher Mutsaka-Makuvaza ◽  
Xiao-Nong Zhou ◽  
Cremance Tshuma ◽  
Eniola Abe ◽  
Justen Manasa ◽  
...  
Keyword(s):  
Schistosoma Haematobium ◽  
Geographical Area ◽  
Endemic Region ◽  
Urogenital Schistosomiasis ◽  
Water Contact ◽  
Additional Information ◽  
Bulinus Globosus ◽  
Species Groups ◽  
One Year ◽  
Low Prevalence

Abstract Background Bulinus 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. Methods Malacological 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. Results Among 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. Conclusions The 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.

scholarly journals Mastomys natalensis (Smith, 1834) as a natural host for Schistosoma haematobium (Bilharz, 1852) Weinland, 1858 x Schistosoma bovis Sonsino, 1876 introgressive hybrids

2021 ◽  
Author(s):  
Boris A.E.S. Savassi ◽  
Gauthier Dobigny ◽  
Jonas R. Etougbétché ◽  
Thalasse T. Avocegan ◽  
François T. Quinsou ◽  
...  
Keyword(s):  
Definitive Host ◽  
Schistosoma Haematobium ◽  
Rattus Rattus ◽  
Introgressive Hybridization ◽  
Mastomys Natalensis ◽  
New Host ◽  
Time Period ◽  
Schistosoma Bovis ◽  
Bulinus Globosus ◽  
Internal Transcribed Spacer Rdna

AbstractCercarial emission of schistosomes is a determinant in the transmission to the definitive host and constitutes a good marker to identify which definitive host is responsible for transmission, mainly in introgressive hybridization situations. Our goal was to test the hypothesis that micro-mammals play a role in Schistosoma haematobium, S. bovis, and/or S. haematobium x S. bovis transmission. Small mammal sampling was conducted in seven semi-lacustrine villages of southern Benin. Among the 62 animals trapped, 50 individuals were investigated for Schistosoma adults and eggs: 37 Rattus rattus, 3 Rattus norvegicus, 9 Mastomys natalensis, and 1 Crocidura olivieri. Schistosoma adults were found in four R. rattus and two M. natalensis, with a local prevalence reaching 80% and 50%, respectively. Two cercarial chronotypes were found from Bulinus globosus experimentally infected with miracidia extracted from naturally infected M. natalensis: a late diurnal and nocturnal chronotype, and an early diurnal, late diurnal, and nocturnal chronotype. The cytochrome C oxidase subunit I mtDNA gene of the collected schistosomes (adults, miracidia, and cercariae) belonged to the S. bovis clade. Eleven internal transcribed spacer rDNA profiles were found; four belonged to S. bovis and seven to S. haematobium x S. bovis. These molecular results together with the observed multi-peak chronotypes add M. natalensis as a new host implicated in S. haematobium x S. bovis transmission. We discuss the origin of the new chronotypes which have become more complex with the appearance of several peaks in a 24-h day. We also discuss how the new populations of offspring may optimize intra-host ecological niche, host spectrum, and transmission time period.

What Are the Factors Affecting Total Sleep Time During Video Polysomnography in Infants?

2020 ◽  
Author(s):  
Grace R. Paul ◽  
Don Hayes ◽  
Dmitry Tumin ◽  
Ish Gulati ◽  
Sudarshan Jadcherla ◽  
...  
Keyword(s):  
Total Sleep Time ◽  
Sleep Time ◽  
Time Of Day ◽  
Apnea Hypopnea Index ◽  
Clinical Factors ◽  
Initial Management ◽  
Factors Affecting ◽  
Modifiable Factors ◽  
Key Points ◽  
Medical Complexity

Objective The aim of the study is to investigate factors affecting total sleep time (TST) during infant polysomnography (PSG) and assess if <4 hours of TST is sufficient for accurate interpretation. Study Design Overall, 242 PSGs performed in 194 infants <6 months of chronological age between March 2013 and December 2015 were reviewed to identify factors that affect TST, including age of infant, location and timing of study, presence of medical complexity, and presence of nasal tubes. A continuum of apnea-hypopnea index (AHI) in relation to TST was reviewed. Data were examined in infants who had TST <4 hours and low AHI. Results Greater TST (p < 0.001) was noted among infants during nocturnal PSGs, at older chronological and post-menstrual ages, and without medical complexity. The presence of nasogastric/impedance probes reduced TST (p = 0.002). Elevated AHIs were identified even in PSGs with TST <4 hours. Short TST may have affected interpretation and delayed initial management in one infant without any inadvertent complications. Conclusion Clinical factors such as PMA and medical complexity, and potentially modifiable factors such as time of day and location of study appeared to affect TST during infant PSGs. TST < 4 hours can be sufficient to identify high AHI allowing physician interpretation. Key Points

Factors affecting pollinator visitation and reproductive success in Sonneratia caseolaris and Aegiceras corniculatum in a mangrove forest in India

2001 ◽  
Vol 17 (3) ◽  
pp. 431-447 ◽  
Author(s):  
SHALINI PANDIT ◽  
B. C. CHOUDHURY
Keyword(s):  
Reproductive Success ◽  
Mangrove Forest ◽  
Time Of Day ◽  
Pollinator Visitation ◽  
Aegiceras Corniculatum ◽  
Factors Affecting ◽  
Plant Reproductive Success ◽  
Sonneratia Caseolaris ◽  
Exclusion Experiments ◽  
Selfing Species

Pollinator visitation to, and the reproductive success of, Sonneratia caseolaris (Sonneratiaceae) and Aegiceras corniculatum (Myrsinaceae) was investigated in a mangrove forest in India. S. caseolaris was shown to be primarily outcrossed and A. corniculatum was shown to be a selfing species. The flowers of both plant species attracted several diurnal and nocturnal visitors. Earlier reports had indicated that S. caseolaris flowered for one night and was exclusively night-pollinated. But flowers of this species were found to be in bloom both at night and during the day, and diurnal visitors to the flowers were more diverse and frequent than nocturnal ones. This was related to the higher volume and energy value of nectar in the morning. The effects of time of day and temperature on visitation rates were quantified. The importance of visitors to plant reproductive success was investigated via controlled visitor-exclusion experiments. Pollinators were expected to be more important for the outcrossing species than for the selfing species, and this was confirmed by the results of the exclusion experiments. In S. caseolaris reproductive success was determined both by pollinator availability and the intensity of flower and fruit predation, while in A. corniculatum it is likely to be resource limited.

scholarly journals Factors affecting the use of physician services in a rural community.

1976 ◽  
Vol 66 (9) ◽  
pp. 865-871 ◽  
Author(s):  
H S Luft ◽  
J C Hershey ◽  
J Morrell
Keyword(s):  
Rural Community ◽  
Physician Services ◽  
Factors Affecting

scholarly journals Simulation of population dynamics of Bulinus globosus: Effects of environmental temperature on production of Schistosoma haematobium cercariae

2018 ◽  
Vol 12 (8) ◽  
pp. e0006651 ◽  
Author(s):  
Chester Kalinda ◽  
Moses J. Chimbari ◽  
William E. Grant ◽  
Hsiao-Hsuan Wang ◽  
Julius N. Odhiambo ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Schistosoma Haematobium ◽  
Environmental Temperature ◽  
Bulinus Globosus

scholarly journals Effect of Mass Chemotherapy and Piped Water on Numbers of Schistosoma Haematobium and Prevalence in Bulinus Globosus in Kwale, Kenya

1988 ◽  
Vol 38 (3) ◽  
pp. 487-495 ◽  
Author(s):  
Shinichi Noda ◽  
Yoshiki Aoki ◽  
Atsuo Sato ◽  
Ngethe D. Muhoho ◽  
John H. Ouma ◽  
...  
Keyword(s):  
Schistosoma Haematobium ◽  
Piped Water ◽  
Bulinus Globosus

Preparation of Hydrophobic Nylon Fabric

2016 ◽  
Vol 11 (1) ◽  
pp. 155892501601100
Author(s):  
Jinmei Du ◽  
Lulu Zhang ◽  
Jing Dong ◽  
Ying Li ◽  
Changhai Xu ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Surface Energy ◽  
Water Contact Angle ◽  
Sem Images ◽  
Water Contact ◽  
Carboxyl Content ◽  
Factors Affecting ◽  
Nylon Fabric ◽  
Butanetetracarboxylic Acid

Surface roughness and surface energy are two important factors affecting the hydrophobicity of nylon fabric. In this study, nylon fabric was treated for hydrophobicity with tetrabutyltitanate (TBT) and octadecylamine (OA) which were respectively responsible for increasing surface roughness and reducing surface energy. In order to enhance the hydrophobicity, In order to further enhance hydrophobicity by increasing available reactive sites, 1,2,3,4–butanetetracarboxylic acid (BTCA) was applied as a pretreatment to the nylon fabric It was found that the carboxyl content of nylon was increased by the BTCA pretreatment. SEM images showed that the TBT treatment produced small particles on nylon fabric which made surface rough. The water contact angle of nylon fabric treated with BTCA, TBT and OA was measured to be 134°, which was much greater than the water contact angle of nylon fabric treated only with OA. This indicated that the surface roughness resulting from the TBT treatment played an important role in improving hydrophobicity of the treated nylon fabric. The resistance to water penetration and the repellency of water spray of nylon fabric treated with BTCA, TBT and OA were respectively measured to be 27.64 mbar and 85 out of 100.

scholarly journals Schistosoma haematobiumin Lake Malaŵi: susceptibility and molecular diversity of the snail hostsBulinus globosusandB. nyassanus

2008 ◽  
Vol 82 (4) ◽  
pp. 377-382 ◽  
Author(s):  
J.R. Stauffer ◽  
H. Madsen ◽  
B. Webster ◽  
K. Black ◽  
D. Rollinson ◽  
...  
Keyword(s):  
Genetic Variability ◽  
Causative Agent ◽  
Schistosoma Haematobium ◽  
Species Complex ◽  
Molecular Diversity ◽  
Lake Malawi ◽  
Intermediate Hosts ◽  
Urinary Schistosomiasis ◽  
Bulinus Globosus ◽  
Mitochondrial Sequences

AbstractIntermediate hosts ofSchistosoma haematobium, the causative agent of urinary schistosomiasis, in Lake Malaŵi include:Bulinus globosus, a member of theB. africanusgroup andB. nyassanus, a diploid member of theB. truncatus/tropicusspecies complex. We compared genetic variability between isolates ofS. haematobiumfrom the southern part of the lake (Cape Maclear), where bothB. globosusandB. nyassanusplay a role as intermediate hosts, and isolates from the northern part, where onlyB. globosusis host. Data show that theS. haematobiumisolates from these two areas of Lake Malaŵi cannot be distinguished using nuclear or mitochondrial sequences and are capable of cross-infections.

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