Arisco Nicholas J, Peterka Cassio, Schwartz Joel, Castro Marcia C
Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA.
Superintendência de Vigilância em Saúde do Amapá, Governo do Estado do Amapá, Macapá, AP, 68902-865, Brazil.
Lancet Reg Health Am. 2025 Jul 17;49:101189. doi: 10.1016/j.lana.2025.101189. eCollection 2025 Sep.
Since 1950, there have been increasingly atypical climatological patterns in the Amazon, some caused by El Niño-Southern Oscillation (ENSO) events (El Niño or La Niña). In 2023-2024, the region faced the most severe droughts in recorded history. These weather patterns are major drivers of malaria. Deforestation has exacerbated these impacts. This study estimates the impact of weather and ENSO events on malaria transmission in the Brazilian Amazon from 2003 to 2022.
We used daily individual-level data on reported malaria cases from the Brazilian Malaria Epidemiological Surveillance Information System (Sivep-Malaria). A case-crossover approach was used to analyze the effects of lagged weather variables and ENSO events on malaria transmission at the Amazon-wide and state levels. Generalized additive quasi-Poisson models were used to assess the influence of ENSO events on malaria cases.
From 2003 to 2022, 5,381,105 malaria cases were recorded in the Brazilian Amazon. Temperatures between 25.64 and 30.85 °C and precipitation >4.46 cm in the week prior to infection increased malaria infection risk up to 9% (95% CI: 8-10%) and 86% (95% CI: 35-155%), respectively. Two- and three-week lagged temperatures >25.64 °C and diurnal variation >6.75 °C reduced malaria infection risk by a maximum of 27% (95% CI: 19-33%) and 59% (95% CI: 52-69%). State-specific variations in relationships were notable. ENSO events significantly influenced weather conditions and malaria transmission, with El Niño and La Niña associated with a net reduction in malaria cases of 2179 (95% CI: 1837, 2520) and 37,258 (95% CI: 37,171, 37,345), respectively, with marked spatiotemporal heterogeneity in effect.
This study clarifies the short- and long-term influences of weather and ENSO events on malaria transmission in the Brazilian Amazon. The results underscore the high degree of heterogeneity in the effects of weather on malaria transmission in the region, and the need for proactive and fine-scale malaria control based on weather forecasting and the development of early warning systems to achieve malaria elimination.
This research was supported by the Division of Intramural Research at the National Institute of Allergy and Infectious Diseases (Award Number: 2U19AI089681-08) and the Foundation for the National Institutes of Health (Award Number: NIH/T32 AI007535).
自1950年以来，亚马孙地区出现了越来越多的非典型气候模式，其中一些是由厄尔尼诺-南方涛动（ENSO）事件（厄尔尼诺或拉尼娜）引起的。在2023 - 2024年，该地区遭遇了有记录以来最严重的干旱。这些天气模式是疟疾的主要驱动因素。森林砍伐加剧了这些影响。本研究估计了2003年至2022年天气和ENSO事件对巴西亚马孙地区疟疾传播的影响。
我们使用了巴西疟疾流行病学监测信息系统（Sivep - Malaria）报告的疟疾病例的每日个体水平数据。采用病例交叉方法分析滞后天气变量和ENSO事件对全亚马孙地区和州一级疟疾传播的影响。使用广义相加拟泊松模型评估ENSO事件对疟疾病例的影响。
2003年至2022年，巴西亚马孙地区记录了5381105例疟疾病例。感染前一周温度在25.64至30.85°C之间以及降水量>4.46厘米分别使疟疾感染风险增加高达9%（95%置信区间：8 - 10%）和86%（95%置信区间：35 - 155%）。滞后两周和三周且温度>25.64°C以及日变化>6.75°C可使疟疾感染风险最大降低27%（95%置信区间：19 - 33%）和59%（95%置信区间：52 - 69%）。各州市之间关系的差异显著。ENSO事件显著影响天气状况和疟疾传播，厄尔尼诺和拉尼娜分别使疟疾病例净减少2179例（95%置信区间：1837, 2520）和37258例（95%置信区间：37171, 37345），影响存在明显的时空异质性。
本研究阐明了天气和ENSO事件对巴西亚马孙地区疟疾传播的短期和长期影响。结果强调了该地区天气对疟疾传播影响的高度异质性，以及基于天气预报和开发预警系统进行积极且精细规模的疟疾控制以实现消除疟疾的必要性。
本研究得到了美国国立过敏与传染病研究所内部研究部（资助编号：2U19AI089681 - 08）和美国国立卫生研究院基金会（资助编号：NIH/T32 AI007535）的支持。
