Geography and ecology of invasive Pseudosuccinea columella (Gastropoda: Lymnaeidae) and implications in the transmission of Fasciola species (Digenea: Fasciolidae) – a review

2022 ◽  
Vol 96 ◽  
Author(s):  
P.I. Ngcamphalala ◽  
M.P. Malatji ◽  
S. Mukaratirwa
Keyword(s):  
North America ◽  
South America ◽  
Fasciola Hepatica ◽  
Sub Saharan Africa ◽  
Snail Species ◽  
Public Health Importance ◽  
Freshwater Bodies ◽  
Important Intermediate ◽  
Endemic Areas ◽  
Sub Saharan

Abstract Pseudosuccinea columella is considered invasive and has become an important intermediate host of both Fasciola species in many regions of the world. This systematic review assessed the geographical distribution of P. columella, and its implications in the transmission of Fasciola hepatica and Fasciola gigantica, globally. A literature search was conducted on Google Scholar, JSTOR and PubMed databases using Boolean operators in combination with predetermined search terms for thematic analysis. Results show that P. columella has been documented in 22 countries from Europe (3), Africa (8), Oceania (2), North America (3) and South America (6). Furthermore, this snail species has shown to adapt to and inhabit a vast array of freshwater bodies including thermal lakes and ditches with acidic soils. Studies showed that P. columella transmits F. hepatica, with natural and experimental infections documented in sub-Saharan Africa, Europe, South America and North America. Experimental infection studies in Cuba showed the presence of P. columella populations resistant to F. hepatica infection. Furthermore, some populations of this invasive snail collected from F. hepatica endemic locations in Brazil, Venezuela, Australia, South Africa, Colombia and Argentina were found without Fasciola infection. As a result, the role played by this snail in the transmission of Fasciola spp. in these endemic areas is still uncertain. Therefore, further studies to detect natural infections are needed in regions/countries where the snail is deemed invasive to better understand the veterinary and public health importance of this snail species in Fasciola-endemic areas and determine the global dispersion of resistant populations of P. columella.

Genetic polymorphism and population structure ofEchinococcus ortleppi

Parasitology ◽  
2016 ◽  
Vol 144 (4) ◽  
pp. 450-458 ◽  
Author(s):  
F. ADDY ◽  
M. WASSERMANN ◽  
F. BANDA ◽  
H. MBAYA ◽  
J. ASCHENBORN ◽  
...  
Keyword(s):  
Genetic Polymorphism ◽  
South America ◽  
Southern Africa ◽  
Dna Sequences ◽  
Intraspecific Variability ◽  
Sensu Stricto ◽  
Sub Saharan Africa ◽  
Geographical Regions ◽  
Sub Saharan ◽  
Eastern And Southern Africa

SUMMARYThe zoonotic cestodeEchinococcus ortleppi(Lopez-Neyra and Soler Planas, 1943) is mainly transmitted between dogs and cattle. It occurs worldwide but is only found sporadically in most regions, with the notable exception of parts of southern Africa and South America. Its epidemiology is little understood and the extent of intraspecific variability is unknown. We have analysed in the present study the genetic diversity among 178E. ortleppiisolates from sub-Saharan Africa, Europe and South America using the complete mitochondrialcox1(1608 bp) andnad1(894 bp) DNA sequences. Genetic polymorphism within the loci revealed 15cox1and sixnad1haplotypes, respectively, and 20 haplotypes of the concatenated genes. Presence of most haplotypes was correlated to geographical regions, and only one haplotype had a wider spread in both eastern and southern Africa. Intraspecific microvariance was low in comparison withEchinococcus granulosussensu stricto, despite the wide geographic range of examined isolates. In addition, the various sub-populations showed only subtle deviation from neutrality and were mostly genetically differentiated. This is the first insight into the population genetics of the enigmatic cattle adaptedEchinococcus ortleppi. It, therefore, provides baseline data for biogeographical comparison amongE. ortleppiendemic regions and for tracing its translocation paths.

scholarly journals Biomass burning fuel consumption dynamics in the tropics and subtropics assessed from satellite

2016 ◽  
Vol 13 (12) ◽  
pp. 3717-3734 ◽  
Author(s):  
Niels Andela ◽  
Guido R. van der Werf ◽  
Johannes W. Kaiser ◽  
Thijs T. van Leeuwen ◽  
Martin J. Wooster ◽  
...  
Keyword(s):  
South America ◽  
Fuel Consumption ◽  
Spatial Patterns ◽  
Field Measurements ◽  
Sub Saharan Africa ◽  
Burned Area ◽  
Return Periods ◽  
Sub Saharan ◽  
In Fire ◽  
Consumption Dynamics

Abstract. Landscape fires occur on a large scale in (sub)tropical savannas and grasslands, affecting ecosystem dynamics, regional air quality and concentrations of atmospheric trace gasses. Fuel consumption per unit of area burned is an important but poorly constrained parameter in fire emission modelling. We combined satellite-derived burned area with fire radiative power (FRP) data to derive fuel consumption estimates for land cover types with low tree cover in South America, Sub-Saharan Africa, and Australia. We developed a new approach to estimate fuel consumption, based on FRP data from the polar-orbiting Moderate Resolution Imaging Spectroradiometer (MODIS) and the geostationary Spinning Enhanced Visible and Infrared Imager (SEVIRI) in combination with MODIS burned-area estimates. The fuel consumption estimates based on the geostationary and polar-orbiting instruments showed good agreement in terms of spatial patterns. We used field measurements of fuel consumption to constrain our results, but the large variation in fuel consumption in both space and time complicated this comparison and absolute fuel consumption estimates remained more uncertain. Spatial patterns in fuel consumption could be partly explained by vegetation productivity and fire return periods. In South America, most fires occurred in savannas with relatively long fire return periods, resulting in comparatively high fuel consumption as opposed to the more frequently burning savannas in Sub-Saharan Africa. Strikingly, we found the infrequently burning interior of Australia to have higher fuel consumption than the more productive but frequently burning savannas in northern Australia. Vegetation type also played an important role in explaining the distribution of fuel consumption, by affecting both fuel build-up rates and fire return periods. Hummock grasslands, which were responsible for a large share of Australian biomass burning, showed larger fuel build-up rates than equally productive grasslands in Africa, although this effect might have been partially driven by the presence of grazers in Africa or differences in landscape management. Finally, land management in the form of deforestation and agriculture also considerably affected fuel consumption regionally. We conclude that combining FRP and burned-area estimates, calibrated against field measurements, is a promising approach in deriving quantitative estimates of fuel consumption. Satellite-derived fuel consumption estimates may both challenge our current understanding of spatiotemporal fuel consumption dynamics and serve as reference datasets to improve biogeochemical modelling approaches. Future field studies especially designed to validate satellite-based products, or airborne remote sensing, may further improve confidence in the absolute fuel consumption estimates which are quickly becoming the weakest link in fire emission estimates.

scholarly journals Neurocysticercosis – A Journey from Pre-independence to Modern India

2016 ◽  
Vol 52 (02) ◽  
pp. 076-099
Author(s):  
Gagandeep Singh ◽  
Monika Singla
Keyword(s):  
Indian Subcontinent ◽  
Taenia Solium ◽  
Population Based ◽  
Sub Saharan Africa ◽  
Ct Scans ◽  
Common Finding ◽  
Cns Involvement ◽  
High Prevalence ◽  
Endemic Areas ◽  
Sub Saharan

ABSTRACTNeurocysticercosis (NCC) is infestation of the human brain by the larva of worm, Taenia solium and is the most prevalent central nervous system (CNS) helminthiasis. The disease is widespread in tropical and subtropical regions of the world, including the Indian subcontinent, China, Sub-Saharan Africa, Central and South America and contributes substantially to the burden of epilepsy in these areas(1) . CNS involvement is seen in 60-90% of systemic cysticercosis. About 2.5 million people worldwide are infected with T. solium, and antibodies to T. solium are seen in up to 25% of people in endemic areas(1-3) . A higher prevalence of epilepsy and seizures in endemic countries is partly because of a high prevalence of cysticercosis in these regions. Seizures are thought to be caused by NCC in as many as 30% of adult patients and in 51% of children in population based endemic regions (2) . About 12% of admissions to neurological services in endemic regions are attributed to NCC and nearly half a million deaths occurring annually worldwide can be attributed directly or indirectly to NCC (Bern et al.). Punctate calcific foci on CT scan are a very common finding in asymptomatic people residing in endemic areas, found in 14-20 % of CT scans. Both seizures and positive cysticercus serology are associated with the detection of cysticerci on CT scans. Seroprevalence using a recently developed CDC- based enzyme-linked immunotransfer blot (EITB) assay is estimated at 8-12% in Latin America and 4.9-24% in Africa and South-East Asia. It is estimated that 20 million people harbour neurocysticercosis worldwide(1) .

scholarly journals Structure of Dark Triad Dirty Dozen Across Eight World Regions

Assessment ◽  
2020 ◽  
pp. 107319112092261
Author(s):  
Radosław Rogoza ◽  
Magdalena Żemojtel-Piotrowska ◽  
Peter K. Jonason ◽  
Jarosław Piotrowski ◽  
Keith W. Campbell ◽  
...  
Keyword(s):  
South America ◽  
Measurement Invariance ◽  
Western Europe ◽  
Dark Triad ◽  
Sub Saharan Africa ◽  
The Past ◽  
World Regions ◽  
Dirty Dozen ◽  
The Difference ◽  
Sub Saharan

The Dark Triad (i.e., narcissism, psychopathy, Machiavellianism) has garnered intense attention over the past 15 years. We examined the structure of these traits’ measure—the Dark Triad Dirty Dozen (DTDD)—in a sample of 11,488 participants from three W.E.I.R.D. (i.e., North America, Oceania, Western Europe) and five non-W.E.I.R.D. (i.e., Asia, Middle East, non-Western Europe, South America, sub-Saharan Africa) world regions. The results confirmed the measurement invariance of the DTDD across participants’ sex in all world regions, with men scoring higher than women on all traits (except for psychopathy in Asia, where the difference was not significant). We found evidence for metric (and partial scalar) measurement invariance within and between W.E.I.R.D. and non-W.E.I.R.D. world regions. The results generally support the structure of the DTDD.

Identifying threatened species in the "south" using new criteria

1998 ◽  
Vol 4 (1) ◽  
pp. 33 ◽  
Author(s):  
A. J. Stattersfield
Keyword(s):  
South America ◽  
Threatened Species ◽  
Pacific Islands ◽  
Numerical Data ◽  
Sub Saharan Africa ◽  
Conservation Action ◽  
Red Lists ◽  
Sub Saharan ◽  
New Criteria ◽  
Clear Objective

The first application of the new IUCN threatened species categories to birds is reviewed. The advantage of this system is that it is characterized by clear, objective, quantitative criteria. However, for many species, requisite numerical data are lacking, and the magnitude of potential threats has to be inferred. Numbers of threatened species are compared for South America, sub-Saharan Africa, and Indo-Pacific Islands. Further analysis identifies the most important countries in terms of priority for conservation action for threatened species, the key habitats for their survival and the main dangers faced. The changes between successive Red Lists indicate a possible extinction crisis of considerable magnitude, whereby half the world's birds could disappear in 800 years. Averting this crisis requires identifying and protecting sites where suites of threatened species co-occur.

scholarly journals When Should the Emphasis on Schistosomiasis Control Move to Elimination?

2018 ◽  
Vol 3 (3) ◽  
pp. 85 ◽  
Author(s):  
W. Secor ◽  
Daniel Colley
Keyword(s):  
South America ◽  
Operational Research ◽  
Sub Saharan Africa ◽  
World Health ◽  
Evidence Based ◽  
Clean Water ◽  
Schistosomiasis Control ◽  
The World ◽  
The Caribbean ◽  
Sub Saharan

The stated goal of the World Health Organization’s program on schistosomiasis is paraphrased as follows: to control morbidity and eliminate transmission where feasible. Switching from a goal of controlling morbidity to interrupting transmission may well be currently feasible in some countries in the Caribbean, some areas in South America, northern Africa, and selected endemic areas in sub-Saharan Africa where there have been improvements in sanitation and access to clean water. However, in most of sub-Saharan Africa, where programmatic interventions still consist solely of annual mass drug administration, such a switch in strategies remains premature. There is a continued need for operational research on how best to reduce transmission to a point where interruption of transmission may be achievable. The level of infection at which it is feasible to transition from control to elimination must also be defined. In parallel, there is also a need to develop and evaluate approaches for achieving and validating elimination. There are currently neither evidence-based methods nor tools for breaking transmission or verifying that it has been accomplished. The basis for these statements stems from numerous studies that will be reviewed and summarized in this article; many, but not all of which were undertaken as part of SCORE, the Schistosomiasis Consortium for Operational Research and Evaluation.

scholarly journals Epidemiological patterns of hepatitis B virus (HBV) in highly endemic areasr

1996 ◽  
Vol 117 (2) ◽  
pp. 313-325 ◽  
Author(s):  
W. J. Edmunds ◽  
G. F. Medley ◽  
D. J. Nokes ◽  
C. J. O'Callaghan ◽  
H. C. Whittle ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
East Asia ◽  
Horizontal Transmission ◽  
Perinatal Transmission ◽  
Sub Saharan Africa ◽  
B Virus ◽  
Age Dependent ◽  
Endemic Areas ◽  
Sub Saharan

SummaryThis paper uses meta-analysis of published data and a deterministic mathematical model of hepatitis B virus (HBV) transmission to describe the patterns of HBV infection in high endemicity areas. We describe the association between the prevalence of carriers and a simple measure of the rate of infection, the age at which half the population have been infected (A50), and assess the contribution of horizontal and perinatal transmission to this association. We found that the two main hyper-endemic areas of sub-Saharan Africa and east Asia have similar prevalences of carriers and values of A50, and that there is a negative nonlinear relationship between A50 and the prevalence of carriers in high endemicity areas (Spearman's Rank, P = 0·0086). We quantified the risk of perinatal transmission and the age-dependent rate of infection to allow a comparison between the main hyper-endemic areas. East Asia was found to have higher prevalences of HBeAg positive mothers and a greater risk of perinatal transmission from HBeAg positive mothers than sub-Saharan Africa, though the differences were not statistically significant. However, the two areas have similar magnitudes and age-dependent rates of horizontal transmission. Results of a simple compartmental model suggest that similar rates of horizontal transmission are sufficient to generate the similar patterns between A50 and the prevalences of carriers. Interrupting horizontal transmission by mass immunization is expected to have a significant, nonlinear impact on the rate of acquisition of new carriers.

scholarly journals High infectious disease burden as a basis for the observed high frequency of asymptomatic SARS-CoV-2 infections in sub-Saharan Africa

2021 ◽  
Vol 4 ◽  
pp. 2
Author(s):  
Kwadwo Asamoah Kusi ◽  
Augustina Frimpong ◽  
Frederica Dedo Partey ◽  
Helena Lamptey ◽  
Linda Eva Amoah ◽  
...  
Keyword(s):  
North America ◽  
Severe Acute Respiratory Syndrome ◽  
Sub Saharan Africa ◽  
World Health ◽  
Susceptible Population ◽  
Mortality And Morbidity ◽  
Quality Healthcare ◽  
The World ◽  
Sub Saharan ◽  
Health Organization

Following the coronavirus outbreaks described as severe acute respiratory syndrome (SARS) in 2003 and the Middle East respiratory syndrome (MERS) in 2012, the world has again been challenged by yet another corona virus, named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 infections were first detected in a Chinese Province in December 2019 and then declared a pandemic by the World Health Organization in March 2020. An infection caused by SARS-CoV-2 may result in asymptomatic, uncomplicated or fatal coronavirus disease 2019 (COVID-19). Fatal disease has been linked with the uncontrolled “cytokine storm” manifesting with complications mostly in people with underlying cardiovascular and pulmonary disease conditions. The severity of COVID-19 disease and the associated mortality has been disproportionately lower in Africa and Asia in comparison to Europe and North America in terms of number of cases and deaths. While persons of colour who live in Europe and North America have been identified as a highly susceptible population due to a combination of several socioeconomic factors and poor access to quality healthcare, this has not been the case in sub-Saharan Africa where inhabitants are even more deprived concerning the said factors. On the contrary, sub-Saharan Africa has recorded the lowest levels of mortality and morbidity associated with the disease, and an overwhelming proportion of infections are asymptomatic. This review discusses the most probable reasons for the significantly fewer cases of severe COVID-19 disease and deaths in sub-Saharan Africa.

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