Malaria patterns across altitudinal zones of Mount Elgon following intensified control and prevention programs in Uganda

Abstract

Background Malaria remains a major tropical vector-borne disease of immense public health concern owing to its debilitating effects in sub-Saharan Africa. Over the past 30 years, the high altitude areas in Eastern Africa have been reported to experience increased cases of malaria. Governments including that of the Republic of Uganda have responded through intensifying programs that can potentially minimize malaria transmission while reducing associated fatalities. However, malaria patterns following these intensified control and prevention interventions in the changing climate remains widely unexplored in East African highland regions. This study thus analyzed malaria patterns across altitudinal zones of Mount Elgon, Uganda. Methods Times-series data on malaria cases (2011–2017) from five level III local health centers occurring across three altitudinal zones; low, mid and high altitude was utilized. Inverse Distance Weighted (IDW) interpolation regression and Mann Kendall trend test were used to analyze malaria patterns. Vegetation attributes from the three altitudinal zones were analyzed using Normalized Difference Vegetation Index (NDVI) was used to determine the Autoregressive Integrated Moving Average (ARIMA) model was used to project malaria patterns for a 7 year period. Results Malaria across the three zones declined over the study period. The hotspots for malaria were highly variable over time in all the three zones. Rainfall played a significant role in influencing malaria burdens across the three zones. Vegetation had a significant influence on malaria in the higher altitudes. Meanwhile, in the lower altitude, human population had a significant positive correlation with malaria cases. Conclusions Despite observed decline in malaria cases across the three altitudinal zones, the high altitude zone became a malaria hotspot as cases variably occurred in the zone. Rainfall played the biggest role in malaria trends. Human population appeared to influence malaria incidences in the low altitude areas partly due to population concentration in this zone. Malaria control interventions ought to be strengthened and strategically designed to achieve no malaria cases across all the altitudinal zones. Integration of climate information within malaria interventions can also strengthen eradication strategies of malaria in such differentiated altitudinal zones.

Uganda Mountain Community Health System—Perspectives and Capacities towards Emerging Infectious Disease Surveillance

“…Although most of these studies related climate change with food security, climate change is generally perceived to be occurring. Previous data within the Kween District and in the whole of Mount Elgon indicated highly variable rainfall and temperature recently compared to the past [27]. This is consistent with opinions from the VHTs in this current study regarding climate trends.…”

“…Specifically, we employed qualitative approaches to assess public health perceptions and disease-reporting infrastructures among rural mountain communities in Eastern Uganda that are critical for responding to emerging infectious disease events. This area has experienced increasing infectious disease outbreaks in recent years, and increased incidence of highland malaria consistent with the influence of climate change on mosquito vector distribution [25][26][27]38,40,42]. The ability to prevent, detect, and respond early to these events at the village level is paramount.…”

“…In mountain communities that have been cited to be among the highly sensitive groups to climate change, such infectious disease scenarios will be pose fundamental impacts on human populations [24]. This impact has been evidenced for other diseases like malaria whose belt has been documented to expand in mountain areas like Mount Elgon [25][26][27]. Climate change tends to alter the environmental conditions providing suitable habitats for disease vectors, e.g., malaria.…”

“…These, among others, include the following: anthrax [38], polio [39], cholera, and Marburg virus [40]. Besides, the malaria belt has expanded in the area [27], thus exemplifying the need for enhanced interventions to prevent further disease outbreak events. VHTs report to the nearest health facility that serves the catchment area where they reside, and they are sometimes referred to as community health volunteers.…”

Associations between environmental covariates and malaria incidence in high transmission settings of Uganda: A distributed non-linear lagged ecological analysis

“…Environmental covariates may also show effects that are delayed in time, requiring examination of the temporal dimension of the exposure-lag-response relationship. Most studies on the relationships between covariates and the malaria burden have relied on speci c time lag, ignoring the cumulative effect of the environmental covariates which may last for a period longer than the current time [7,14,15]. From the biological perspective, different periods including time for mosquito to develop, period of parasites within the mosquito, and incubation period of the parasites within human body makes the assumption of a speci c time lag unrealistic, as the observed effect of the environmental covariates in a given lag may be a cumulative effect from the preceding lags.…”