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A study of rainfall trends and temporal variations within seven sub-basins of Uganda spanning from 1940 to 2009 has been made. Rainfall climatologies are constructed from observational data, using 36 station records which reflect hydroclimatic conditions. Long-term changes in rainfall characteristics were determined by non-parametric tests (Mann-Kendall and Sen's T tests), coefficient of variation (CV), precipitation concentration index and drought severity index. Magnitude of change was estimated by applying Sen's estimator of slope. Decadal variability of rainfall with marked seasonal cycles is evident. Temporal variability of drought patterns is detected. Variations in annual rainfall are low with no significant trends observed in the main drainage sub-basins. Significant trends occur in October, November, December and January. A noticeable decrease in the annual total rainfall was observed mostly in northwestern and southwestern sub-basins. Rainfall trend in the second normal of June-July-August (JJA) was decreasing in all the main drainage sub-basins.Key words trend analysis; Mann-Kendall; Sen's T test; precipitation concentration index; drought severity index; drainage sub-basins; Uganda La nature des précipitations dans les principaux sous-bassins de l'Ouganda Résumé Une étude des tendances et des variations temporelles des précipitations dans sept sous-bassins de l'Ouganda à été réalisée sur lapériode allant de 1940 à 2009. La climatologie des précipitations a été construite à partir des données observées dans 36 stations représentatives des conditions hydroclimatiques. Les changements à long terme des caractéristiques des précipitations, coefficient de variation, indice de concentration des précipitations et indice de gravité de la sécheresse, ont été déterminés par des tests non paramétriques (test de Mann-Kendall et test T de Sen). L'amplitude du changement a été estimée en appliquant l'estimateur de pente de Sen. La variabilité décennale des précipitations aux cycles saisonniers marqués est évidente. La variabilité temporelle des phénomènes de sécheresse a été détectée. Les variations des précipitations annuelles sont faibles sans tendances significatives observées dans les principaux sous-bassins. Des tendances significatives ont été observées en octobre, novembre, décembre et janvier. Une diminution notable des précipitations totales annuelles a été observée principalement dans les sous bassins du Nord-ouest et du Sud-ouest. Une tendance à la décroissance des précipitations en juin-juillet-août (JJA) a été observée dans tous les sous-bassins principaux.

Early studies of weather, seasonality, and environmental influences on COVID-19 have yielded inconsistent and confusing results. To provide policy-makers and the public with meaningful and actionable environmentally-informed COVID-19 risk estimates, the research community must meet robust methodological and communication standards.

The suitability of present and future climates for 30 Rhipicephalus species in Africa are predicted using a simple climate envelope model as well as a Division of Atmospheric Research Limited-Area Model (DARLAM). DARLAM's predictions are compared with the mean outcome from two global circulation models. East Africa and South Africa are considered the most vulnerable regions on the continent to climate-induced changes in tick distributions and tick-borne diseases. More than 50% of the species examined show potential range expansion and more than 70% of this range expansion is found in economically important tick species. More than 20% of the species experienced range shifts of between 50 and 100%. There is also an increase in tick species richness in the south-western regions of the sub-continent. Actual range alterations due to climate change may be even greater since factors like land degradation and human population increase have not been included in this modelling process. However, these predictions are also subject to the effect that climate change may have on the hosts of the ticks, particularly those that favour a restricted range of hosts. Where possible, the anticipated biological implications of the predicted changes are explored.