scholarly journals Space and time predictions of schistosomiasis snail host population dynamics across hydrologic regimes in Burkina Faso

2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Javier Perez-Saez ◽  
Theophile Mande ◽  
Andrea Rinaldo
Keyword(s):  
Population Dynamics ◽  
Burkina Faso ◽  
Spatial Patterns ◽  
Large Scale ◽  
Remotely Sensed ◽  
Host Population ◽  
Snail Host ◽  
Intermediate Hosts ◽  
National Scale ◽  
Temperature And Precipitation

The ecology of the aquatic snails that serve as obligatory intermediate hosts of human schistosomiasis is driven by climatic and hydrological factors which result in specific spatial patterns of occurrence and abundance. These patterns in turn affect, jointly with other determinants, the geography of the disease and the timing of transmission windows, with direct implications for the success of control and elimination programmes in the endemic countries. We address the spatial distribution of the intermediate hosts and their seasonal population dynamics within a predictive ecohydrological framework developed at the national scale for Burkina Faso, West Africa. The approach blends river network-wide information on hydrological ephemerality which conditions snail habitat suitability together with ensembles of discrete time ecological models forced by remotely sensed estimates of temperature and precipitation. The models were validated against up to four years of monthly snail abundance data. Simulations of model ensembles accounting for the uncertainty in remotely sensed products adequately reproduce observed snail demographic fluctuations observed in the field across habitat types, and produce national scale predictions by accounting for spatial patterns of hydrological conditions in the country. Geospatial estimates of seasonal snail abundance underpin large-scale, spatially explicit predictions of schistosomiasis incidence. This work can therefore contribute to the development of disease control and elimination programmes.

Monogenean parasites from fishes of the Vaal Dam, Gauteng Province, South Africa. I. Winter survey versus summer survey comparison from Labeo capensis (Smith, 1841) and Labeo umbratus (Smith, 1841) hosts

2014 ◽  
Vol 59 (1) ◽  
Author(s):  
Dionne Crafford ◽  
Wilmien Luus-Powell ◽  
Annemariè Avenant-Oldewage
Keyword(s):  
Population Dynamics ◽  
Large Scale ◽  
Experimental Studies ◽  
Attachment Site ◽  
Host Population ◽  
Site Preference ◽  
Gauteng Province ◽  
Active Choice ◽  
Vaal Dam ◽  
Intensive Aquaculture

AbstractIndigenous South African Labeo spp. show promise with regard to development of semi-intensive aquaculture, yet little research on their monogenean fauna has been conducted. Ecological aspects of monogenean fauna of the moggel Labeo umbratus (Smith 1841) and the Orange River mudfish Labeo capensis (Smith 1841), as recorded during both winter and summer sampling surveys, are reported here. Fish were collected using gill nets, euthanized and gills removed and examined to both quantify parasite numbers and distribution on the gills. Results obtained support the hypothesis that gill site preference is not due to active choice for a particular attachment site, but rather a result of water flow over gills during respiration in conjunction with fish behaviour and habitat use. Interaction between individual elements investigated (temperature effects, parasite population dynamics and host population dynamics) may be largely responsible for seasonal differences in infection statistics of monogenean parasites. Such interactions should be investigated in future large scale ecological studies, in combination with experimental studies, to further elucidate these effects.

Infection patterns of trematodes across size classes of an invasive snail species using field and laboratory studies

Parasitology ◽  
2018 ◽  
Vol 146 (4) ◽  
pp. 438-444 ◽  
Author(s):  
Rebecca Z. Bachtel ◽  
Matthew Rittenhouse ◽  
Gregory J. Sandland ◽  
Jennifer A. H. Koop
Keyword(s):  
Host Population ◽  
Snail Host ◽  
Host Susceptibility ◽  
Snail Species ◽  
Infection Prevalence ◽  
Laboratory Studies ◽  
Intermediate Hosts ◽  
Susceptible Host ◽  
Transmission Potential ◽  
River Region

AbstractIn the Upper Mississippi River Region, invasive faucet snails (Bithynia tentaculata) and their trematode parasites have been implicated in more than 182 000 waterfowl deaths since 1996. Estimating transmission potential depends on accurate assessments of susceptible host population size. However, little is known about the mechanisms underlying snail–host susceptibility in this system. Prior field studies suggest that very small, likely young, faucet snails are less suitable secondary intermediate hosts. Here, we test whether the patterns observed in the field are because small snails (1) are refractory to infection by cercariae, (2) die from infection and are removed from sampled populations, and/or (3) are not preferred by cercariae. Our own field collections were consistent with the observation that smaller faucet snails exhibit lower metacercarial infection prevalence and abundance than larger snails. However, laboratory-based experiments show that smaller snails were actually more susceptible to infection than larger snails. Moreover, the smallest snail size class had significantly higher mortality than larger snails following infection, which may explain their reduced infection levels observed in the field. Our study demonstrates the importance of pairing field and laboratory studies to better understand mechanisms underlying patterns of infection.

scholarly journals Analysis of 220 Years of Floodplain Population Dynamics in the US at Different Spatial Scales

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 141
Author(s):  
Firoza Akhter ◽  
Maurizio Mazzoleni ◽  
Luigia Brandimarte
Keyword(s):  
Population Dynamics ◽  
Large Scale ◽  
Spatial Scales ◽  
National Level ◽  
State Level ◽  
Economic Activities ◽  
Protection Measures ◽  
Management Planning ◽  
The Us ◽  
Over Time

In this study, we explore the long-term trends of floodplain population dynamics at different spatial scales in the contiguous United States (U.S.). We exploit different types of datasets from 1790–2010—i.e., decadal spatial distribution for the population density in the US, global floodplains dataset, large-scale data of flood occurrence and damage, and structural and nonstructural flood protection measures for the US. At the national level, we found that the population initially settled down within the floodplains and then spread across its territory over time. At the state level, we observed that flood damages and national protection measures might have contributed to a learning effect, which in turn, shaped the floodplain population dynamics over time. Finally, at the county level, other socio-economic factors such as local flood insurances, economic activities, and socio-political context may predominantly influence the dynamics. Our study shows that different influencing factors affect floodplain population dynamics at different spatial scales. These facts are crucial for a reliable development and implementation of flood risk management planning.

scholarly journals Fencing affects African wild dog movement patterns and population dynamics

Oryx ◽  
2021 ◽  
pp. 1-9
Author(s):  
Helen M. K. O'Neill ◽  
Sarah M. Durant ◽  
Stefanie Strebel ◽  
Rosie Woodroffe
Keyword(s):  
Population Dynamics ◽  
Large Scale ◽  
Animal Movement ◽  
Landscape Connectivity ◽  
Ecological Impact ◽  
Movement Patterns ◽  
Wrong Side ◽  
African Wild Dog ◽  
Wild Dog ◽  
Wild Dogs

Abstract Wildlife fences are often considered an important tool in conservation. Fences are used in attempts to prevent human–wildlife conflict and reduce poaching, despite known negative impacts on landscape connectivity and animal movement patterns. Such impacts are likely to be particularly important for wide-ranging species, such as the African wild dog Lycaon pictus, which requires large areas of continuous habitat to fulfil its resource requirements. Laikipia County in northern Kenya is an important area for wild dogs but new wildlife fences are increasingly being built in this ecosystem. Using a long-term dataset from the area's free-ranging wild dog population, we evaluated the effect of wildlife fence structure on the ability of wild dogs to cross them. The extent to which fences impeded wild dog movement differed between fence designs, although individuals crossed fences of all types. Purpose-built fence gaps increased passage through relatively impermeable fences. Nevertheless, low fence permeability can lead to packs, or parts of packs, becoming trapped on the wrong side of a fence, with consequences for population dynamics. Careful evaluation should be given to the necessity of erecting fences; ecological impact assessments should incorporate evaluation of impacts on animal movement patterns and should be undertaken for all large-scale fencing interventions. Where fencing is unavoidable, projects should use the most permeable fencing structures possible, both in the design of the fence and including as many purpose-built gaps as possible, to minimize impacts on wide-ranging wildlife.

scholarly journals Genotypic distribution of human oncogenic papillomaviruses in sexually active women in Burkina Faso: Central, Central-Eastern and Hauts-Bassins regions

2020 ◽  
Vol 11 (1) ◽  
pp. 125-136
Author(s):  
Rogomenoma Alice Ouedraogo ◽  
Théodora Mahoukèdè Zohoncon ◽  
Ina Marie Angèle Traore ◽  
Abdoul Karim Ouattara ◽  
Sindimalgdé Patricia Guigma ◽  
...  
Keyword(s):  
Burkina Faso ◽  
Large Scale ◽  
Hpv Infection ◽  
Cross Sectional Study ◽  
Sexually Active ◽  
Cervical Lesions ◽  
Cross Sectional ◽  
Genotypic Distribution ◽  
Hpv Genotypes ◽  
Central Eastern

AbstractObjectivethis study was conducted to determine the distribution of high-risk human papillomavirus (HR-HPV) genotypes in women in the general population of three regions of Burkina Faso.MethodThis multicenter, descriptive cross-sectional study involved 1321 sexually active women in five cities in three regions of Burkina Faso: Central, Central-Eastern and Hauts-Bassins regions. After collection of endocervical specimens, pre-cervical lesions were screened by visual inspection with acetic acid and lugol (VIA / VILI). HR-HPV genotypes were characterized by multiplex real-time PCR after extraction of viral DNA.ResultsThe mean age of women was 31.98 ± 10.09 years. The HR-HPV infection in the three regions ranged from 26.16% to 43.26% with 35.42% as overall prevalence in women. The most common HR-HPV genotypes in descending order were: HPV 56, 52, 66, 59, 39, 51, 18, 35. The prevalence of bivalent vaccine genotypes (HPV16 / 18) was 7.83% against 63.78% of genotypes not covered by HPV vaccine; 36.32% (170/468) of women had multiple concomitant HR-HPV infections.Conclusionthis study showed significant regional variation and high prevalence of HR-HPV infection in women. The predominant genotypes differ from those covered by available vaccines in Burkina Faso. These results will help guide our health policies towards better prevention of cervical cancer. The diversity of oncogenic genotypes is sparking a large-scale study in the West African sub-region, particularly in cases of cancer and the introduction of the nonavalent vaccine which includes HPV 52 found among the predominant genotypes in this study.

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