Spatio-temporal distribution of fire activity in protected areas of Sub-Saharan Africa derived from MODIS data

SUMMARYMeningococcal meningitis is a major public health problem in the African Belt. Despite the obvious seasonality of epidemics, the factors driving them are still poorly understood. Here, we provide a first attempt to predict epidemics at the spatio-temporal scale required for in-year response, using a purely empirical approach. District-level weekly incidence rates for Niger (1986–2007) were discretized into latent, alert and epidemic states according to pre-specified epidemiological thresholds. We modelled the probabilities of transition between states, accounting for seasonality and spatio-temporal dependence. One-week-ahead predictions for entering the epidemic state were generated with specificity and negative predictive value >99%, sensitivity and positive predictive value >72%. On the annual scale, we predict the first entry of a district into the epidemic state with sensitivity 65·0%, positive predictive value 49·0%, and an average time gained of 4·6 weeks. These results could inform decisions on preparatory actions.

Download Full-text

Genetic diversity of trypanosome species in tsetse flies (Glossina spp.) in Nigeria

Parasites & Vectors ◽

10.1186/s13071-019-3718-y ◽

2019 ◽

Vol 12 (1) ◽

Cited By ~ 1

Author(s):

Judith Sophie Weber ◽

Sen Claudine Henriette Ngomtcho ◽

Stephen Saikiu Shaida ◽

Gloria Dada Chechet ◽

Thaddeus Terlumun Gbem ◽

...

Keyword(s):

Genetic Diversity ◽

Protected Areas ◽

National Parks ◽

Sub Saharan Africa ◽

Tsetse Flies ◽

Insect Vector ◽

Limited Information ◽

Sub Saharan ◽

Dynamic Populations

Abstract Background Trypanosomes cause disease in humans and livestock in sub-Saharan Africa and rely on tsetse flies as their main insect vector. Nigeria is the most populous country in Africa; however, only limited information about the occurrence and diversity of trypanosomes circulating in the country is available. Methods Tsetse flies were collected from five different locations in or adjacent to protected areas, i.e. national parks and game reserves, in Nigeria. Proboscis and gut samples were analysed for trypanosome DNA by molecular amplification of the internal transcribed spacer 1 (ITS1) region and part of the trypanosome specific glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) gene. Results The most abundant Trypanosoma species found in the tsetse gut was T. grayi, a trypanosome infecting crocodiles. It was ubiquitously distributed throughout the country, accounting for over 90% of all cases involving trypanosomes. Trypanosoma congolense was detected in gut samples from all locations except Cross River National Park, but not in the proboscis, while T. brucei (sensu lato) was not detected at all. In proboscis samples, T. vivax was the most prominent. The sequence diversity of gGAPDH suggests that T. vivax and T. grayi represent genetically diverse species clusters. This implies that they are highly dynamic populations. Conclusions The prevalence of animal pathogenic trypanosomes throughout Nigeria emphasises the role of protected areas as reservoirs for livestock trypanosomes. The genetic diversity observed within T. vivax and T. grayi populations might be an indication for changing pathogenicity or host range and the origin and consequences of this diversity has to be further investigated.

Download Full-text

Epidemiology and hypothetical transmission cycles of Trichinella infections in the Greater Kruger National Park of South Africa: an example of host-parasite interactions in an environment with minimal human interactions

Parasite ◽

10.1051/parasite/2020010 ◽

2020 ◽

Vol 27 ◽

pp. 13

Author(s):

Louis J. La Grange ◽

Samson Mukaratirwa

Keyword(s):

South Africa ◽

Protected Areas ◽

National Parks ◽

National Park ◽

Feeding Habits ◽

Kruger National Park ◽

Sub Saharan Africa ◽

Ecological Niches ◽

Transmission Cycles ◽

Sub Saharan

Knowledge on the epidemiology, host range and transmission of Trichinella spp. infections in different ecological zones in southern Africa including areas of wildlife-human interface is limited. The majority of reports on Trichinella infections in sub-Saharan Africa were from wildlife resident in protected areas. Elucidation of the epidemiology of the infections and the prediction of hosts involved in the sylvatic cycles within specific ecological niches is critical. Of recent, there have been reports of Trichinella infections in several wildlife species within the Greater Kruger National Park (GKNP) of South Africa, which has prompted the revision and update of published hypothetical transmission cycles including the hypothetical options based previously on the biology and feeding behaviour of wildlife hosts confined to the GKNP. Using data gathered from surveillance studies and reports spanning the period 1964–2019, confirmed transmission cycles and revised hypothesized transmission cycles of three known Trichinella species (T. zimbabwensis, Trichinella T8 and T. nelsoni) are presented. These were formulated based on the epidemiological factors, feeding habits of hosts and prevalence data gathered from the GKNP. We presume that the formulated sylvatic cycles may be extrapolated to similar national parks and wildlife protected areas in sub-Saharan Africa where the same host and parasite species are known to occur. The anecdotal nature of some of the presented data confirms the need for more intense epidemiological surveillance in national parks and wildlife protected areas in the rest of sub-Saharan Africa to unravel the epidemiology of Trichinella infections in these unique and diverse protected landscapes.

Download Full-text

Subnational violent conflict forecasts for sub-Saharan Africa, 2015–65, using climate-sensitive models

Journal of Peace Research ◽

10.1177/0022343316682064 ◽

2017 ◽

Vol 54 (2) ◽

pp. 175-192 ◽

Cited By ~ 23

Author(s):

Frank DW Witmer ◽

Andrew M Linke ◽

John O’Loughlin ◽

Andrew Gettelman ◽

Arlene Laing

Keyword(s):

Climate Change ◽

Violent Conflict ◽

Sub Saharan Africa ◽

Population Projections ◽

High Fertility ◽

Climate Change Scenarios ◽

Political Rights ◽

Monthly Data ◽

Spatio Temporal ◽

Sub Saharan

How will local violent conflict patterns in sub-Saharan Africa evolve until the middle of the 21st century? Africa is recognized as a particularly vulnerable continent to environmental and climate change since a large portion of its population is poor and reliant on rain-fed agriculture. We use a climate-sensitive approach to model sub-Saharan African violence in the past (geolocated to the nearest settlements) and then forecast future violence using sociopolitical factors such as population size and political rights (governance), coupled with temperature anomalies. Our baseline model is calibrated using 1° gridded monthly data from 1980 to 2012 at a finer spatio-temporal resolution than existing conflict forecasts. We present multiple forecasts of violence under alternative climate change scenarios (optimistic and current global trajectories), of political rights scenarios (improvement and decline), and population projections (low and high fertility). We evaluate alternate shared socio-economic pathways (SSPs) by plotting violence forecasts over time and by detailed mapping of recent and future levels of violence by decade. The forecasts indicate that a growing population and rising temperatures will lead to higher levels of violence in sub-Saharan Africa if political rights do not improve. If political rights continue to improve at the same rate as observed over the last three decades, there is reason for optimism that overall levels of violence will hold steady or even decline in Africa, in spite of projected population increases and rising temperatures.

Download Full-text

Spatial and temporal distribution of soil-transmitted helminth infection in sub-Saharan Africa: a systematic review and geostatistical meta-analysis

The Lancet Infectious Diseases ◽

10.1016/s1473-3099(14)71004-7 ◽

2015 ◽

Vol 15 (1) ◽

pp. 74-84 ◽

Cited By ~ 88

Author(s):

Dimitrios-Alexios Karagiannis-Voules ◽

Patricia Biedermann ◽

Uwem F Ekpo ◽

Amadou Garba ◽

Erika Langer ◽

...

Keyword(s):

Systematic Review ◽

Helminth Infection ◽

Meta Analysis ◽

Temporal Distribution ◽

Sub Saharan Africa ◽

Spatial And Temporal Distribution ◽

Sub Saharan

Download Full-text

Estimation of Woody and Herbaceous Leaf Area Index in Sub‐Saharan Africa Using MODIS Data

Journal of Geophysical Research Biogeosciences ◽

10.1002/2017jg004105 ◽

2018 ◽

Vol 123 (1) ◽

pp. 3-17 ◽

Cited By ~ 8

Author(s):

M. N. Kahiu ◽

N. P. Hanan

Keyword(s):

Leaf Area Index ◽

Leaf Area ◽

Sub Saharan Africa ◽

Area Index ◽

Modis Data ◽

Sub Saharan

Download Full-text

Spatial and seasonal patterns of FMD primary outbreaks in cattle in Zimbabwe between 1931 and 2016

Veterinary Research ◽

10.1186/s13567-019-0690-7 ◽

2019 ◽

Vol 50 (1) ◽

Cited By ~ 1

Author(s):

Laure Guerrini ◽

Davies Mubika Pfukenyi ◽

Eric Etter ◽

Jérémy Bouyer ◽

Chenjerai Njagu ◽

...

Keyword(s):

Protected Areas ◽

Southern Africa ◽

Production Systems ◽

Temporal Distribution ◽

Foot And Mouth Disease ◽

Control Measures ◽

Political Crisis ◽

Small Scale ◽

Temporal Occurrence ◽

Spatio Temporal

Abstract Foot and mouth disease (FMD) is an important livestock disease impacting mainly intensive production systems. In southern Africa, the FMD virus is maintained in wildlife and its control is therefore complicated. However, FMD control is an important task to allow countries access to lucrative foreign meat market and veterinary services implement drastic control measures on livestock populations living in the periphery of protected areas, negatively impacting local small-scale livestock producers. This study investigated FMD primary outbreak data in Zimbabwe from 1931 to 2016 to describe the spatio-temporal distribution of FMD outbreaks and their potential drivers. The results suggest that: (i) FMD outbreaks were not randomly distributed in space across Zimbabwe but are clustered in the Southeast Lowveld (SEL); (ii) the proximity of protected areas with African buffalos was potentially responsible for primary FMD outbreaks in cattle; (iii) rainfall per se was not associated with FMD outbreaks, but seasons impacted the temporal occurrence of FMD outbreaks across regions; (iv) the frequency of FMD outbreaks increased during periods of major socio-economic and political crisis. The differences between the spatial clusters and other areas in Zimbabwe presenting similar buffalo/cattle interfaces but with fewer FMD outbreaks can be interpreted in light of the recent better understanding of wildlife/livestock interactions in these areas. The types of wildlife/livestock interfaces are hypothesized to be the key drivers of contacts between wildlife and livestock, triggering a risk of FMD inter-species spillover. The management of wildlife/livestock interfaces is therefore crucial for the control of FMD in southern Africa.

Download Full-text

A spatio-temporal analysis of peri-urbanisation in sub-Saharan Africa: a case study from Lobatse, Botswana

African Geographical Review ◽

10.1080/19376812.2013.862477 ◽

2014 ◽

Vol 33 (2) ◽

pp. 174-201 ◽

Cited By ~ 1

Author(s):

Abiodun Ayooluwa Areola ◽

Thando D. Gwebu ◽

Reuben J. Sebego

Keyword(s):

Temporal Analysis ◽

Sub Saharan Africa ◽

Spatio Temporal ◽

Sub Saharan

Download Full-text

Fire Activity and Fuel Consumption Dynamics in Sub-Saharan Africa

Remote Sensing ◽

10.3390/rs10101591 ◽

2018 ◽

Vol 10 (10) ◽

pp. 1591 ◽

Cited By ~ 5

Author(s):

Gareth Roberts ◽

Martin Wooster ◽

Weidong Xu ◽

Jiangping He

Keyword(s):

Fuel Consumption ◽

Southern Hemisphere ◽

Land Surface ◽

Sub Saharan Africa ◽

Fuel Load ◽

Biomass Combustion ◽

Fire Emissions ◽

Fire Activity ◽

Sub Saharan ◽

The Impact

African landscape fires are widespread, recurrent and temporally dynamic. They burn large areas of the continent, modifying land surface properties and significantly affect the atmosphere. Satellite Earth Observation (EO) data play a pivotal role in capturing the spatial and temporal variability of African biomass burning, and provide the key data required to develop fire emissions inventories. Active fire observations of fire radiative power (FRP, MW) have been shown to be linearly related to rates of biomass combustion (kg s−1). The Meteosat FRP-PIXEL product, delivered in near real-time by the EUMETSAT Land Surface Analysis Satellite Applications Facility (LSA SAF), maps FRP at 3 km resolution and 15-min intervals and these data extend back to 2004. Here we use this information to assess spatio-temporal variations in fire activity across sub-Saharan Africa, and identify an overall trend of decreasing annual fire activity and fuel consumption, agreeing with the widely-used Global Fire Emissions Database (GFEDv4) based on burned area measures. We provide the first comprehensive assessment of relationships between per-fire FRE-derived fuel consumption (Tg dry matter, DM) and temporally integrated Moderate Resolution Imaging Spectroradiometer (MODIS) net photosynthesis (PSN) (Tg, which can be converted into pre-fire fuel load estimates). We find very strong linear relationships over southern hemisphere Africa (mean r = 0.96) that are partly biome dependent, though the FRE-derived fuel consumptions are far lower than those derived from the accumulated PSN, with mean fuel consumptions per unit area calculated as 0.14 kg DM m−2. In the northern hemisphere, FRE-derived fuel consumption is also far lower and characterized by a weaker linear relationship (mean r = 0.76). Differences in the parameterization of the biome look up table (BLUT) used by the MOD17 product over Northern Africa may be responsible but further research is required to reconcile these differences. The strong relationship between fire FRE and pre-fire fuel load in southern hemisphere Africa is encouraging and highlights the value of geostationary FRP retrievals in providing a metric that relates very well to fuel consumption and fire emission variations. The fact that the estimated fuel consumed is only a small fraction of the fuel available suggests underestimation of FRE by Spinning Enhanced Visible and Infrared Imager (SEVIRI) and/or that the FRE-to-fuel consumption conversion factor of 0.37 MJ kg−1 needs to be adjusted for application to SEVIRI. Future geostationary imaging sensors, such as on the forthcoming Meteosat Third Generation (MTG), will reduce the impact of this underestimation through its ability to detect even smaller and shorter-lived fires than can the current second generation Meteosat.

Download Full-text