Temperature Variability and Occurrence of Diarrhoea in Children under Five-Years-Old in Cape Town Metropolitan Sub-Districts

Abstract

This paper describes the relationship between temperature change and diarrhoea in under five-year-old children in the Cape Town Metropolitan Area (CTMA) of South Africa. The study used climatic and aggregated surveillance diarrhoea incidence data of two peak periods of seven months each over two consecutive years. A Poisson regression model and a lagged Poisson model with autocorrelation was performed to test the relationship between climatic parameters (minimum and maximum temperature) and incidence of diarrhoea. In total, 58,617 cases of diarrhoea occurred in the CTMA, which is equivalent to 8.60 cases per 100 population under five years old for the study period. The mixed effect overdispersed Poisson model showed that a cluster adjusted effect of an increase of 5 °C in minimum and maximum temperature results in a 40% (Incidence risk ratio IRR: 1.39, 95% CI 1.31–1.48) and 32% (IRR: 1.32, 95% CI: 1.22–1.41) increase in incident cases of diarrhoea, respectively, for the two periods studied. Autocorrelation of one-week lag (Autocorrelation AC 1) indicated that a 5 °C increase in minimum and maximum temperature led to 15% (IRR: 1.46, 95% CI: 1.09–1.20) and 6% (IRR: 1.06, 95% CI: 1.01–1.12) increase in diarrhoea cases, respectively. In conclusion, there was an association between an increase in minimum and maximum temperature, and the rate at which diarrhoea affected children under the age of five years old in the Cape Town Metropolitan Area. This finding may have implications for the effects of global warming and requires further investigation.

Association between Childhood Diarrhoeal Incidence and Climatic Factors in Urban and Rural Settings in the Health District of Mbour, Senegal

“…The effect of high temperature on diarrhoeal incidence of the same month observed in the health district of Mbour may result from many factors. For instance, high temperature may lead to increased exposure to bacteria, parasites and other agents causing diarrhoea, implying that gastrointestinal diseases are more likely to occur during the hottest months of the year [ 14 , 50 ]. The associations of monthly temperatures (LST Day , LST Night , LST and LST variability) with diarrhoea incidence of the following month in the health district of Mbour were negative in the multivariate analyses.…”

“…The relationship between climate and diarrhoeal diseases is complex because of the myriad confounding variables and transmission routes that can affect the disease incidence and the fact that diarrhoea is caused by different pathogens [ 10 , 11 , 12 , 13 ]. Despite this complexity, evidence suggests that climatic factors, such as temperature and rainfall, are associated with the occurrence of diarrhoea; indeed an increase in temperature is associated with an increase in the incidence of diarrhoea [ 14 , 15 , 16 , 17 , 18 , 19 ]. However, previous studies exploring the effects of climatic factors on diarrhoea are inconclusive.…”

Climate change adaptation in South Africa: a case study on the role of the health sector

“…Such applications have been developed to support malaria programming in the country [55], where temporal patterns in temperature, rainfall and sea surface temperature can forecast changes in malaria incidence and the geographical expansion of disease outbreaks [3,56,57]. Further, as shown in a study in Cape Town, close monitoring of ambient temperature, can predict spikes in incidence of diarrhoeal disease, allowing health services to prepare for rises in admissions and outpatient visits [9]. Similarly, another study across several provinces noted that anomalous high rainfall precedes outbreaks of Rift Valley fever by one month and that this finding can be used to forewarn epidemics in affected areas of the country [58].…”

“…Extreme weather events are the most noticeable effects to date, especially the drought in the Western Cape and wildfires, but rises in vector-and waterborne diseases are also gaining prominence. Global warming, which manifests as climate variability, has already been implicated in increased transmission of malaria, Rift Valley Fever, schistosomiasis, cholera and other diarrheal pathogens, and Avian influenza in the country [3][4][5][6][7][8][9][10]. Studies have documented the considerable impact of high ambient temperatures on mortality in the country, with mortality rises of 0.9% per 1°C above certain thresholds, and considerably higher levels in the elderly and young children [11,12].…”

El Niño Southern Oscillation (ENSO) and Health: An Overview for Climate and Health Researchers

“…Notwithstanding the complex pathways linking climate anomalies and diarrhoea [70] and the challenges this poses for quantifying the effects of weather and climate on water-associated diseases in general [71,72], diarrhoeal illness is generally sensitive to climate anomalies [74,75,76,77,78,79] with unusually warm conditions conducive to enhanced pathogen replication and survival rates while rainfall surpluses may transport faecal matter into water courses with micro-organisms becoming concentrated in water bodies during periods of rainfall deficit. While Demisse and Mengisitie [80] noted that El Niño has an impact on diarrhoea incidence for a number of major geographic regions, many of the cited papers address temperature/rainfall -diarrhoea association as opposed to climate driven variations in diarrhoea moderated by ENSO.…”