Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard TH Chan School of Public Health, Boston, MA, USA.
Vector Control Services, Ministry of Public Health, Georgetown, Guyana.
Lancet Planet Health. 2021 Oct;5(10):e731-e738. doi: 10.1016/S2542-5196(21)00203-5.
Guyana reported a significant rise in malaria between 2008 and 2014. As there was no evidence of impairment of national malaria control strategies, public health authorities attributed the surge to a temporal increase in gold mining activity in forested regions. However, systematic analysis of this association is lacking because of the difficulties associated with collecting reliable data for both malaria and mining. We aimed to investigate the association between the international gold price and Plasmodium falciparum malaria transmission in Guyana between 2007 and 2019. We also aimed to evaluate the association between P falciparum cases and the El Niño-Southern Oscillation pattern, which has previously been suggested as a major driver of malaria.
We used national malaria surveillance data from Guyana to estimate the correlation over time between the international gold price and reported P falciparum infections in individuals who were likely to be involved in mining activities (ie, men and boys aged between 15 and 50 years who were living in mining regions) for each month between 2007 and 2019. We compared the estimates with those obtained from individuals who were unlikely to be directly involved in mining activities (ie, women, children aged 12 years and younger, and adults aged over 70 years) and estimates obtained from individuals living in non-mining regions. We also evaluated the correlation between P falciparum infections and the El Niño-Southern Oscillation pattern in the same subpopulations and time period. Lastly, we evaluated the performance of a statistical model formulated to estimate P falciparum infections in real time using the international gold price as the predictor variable.
The proportion of P falciparum malaria cases in temporary residents, which was used as a proxy for circulating individuals involved in gold mining, was highest during the years of peak gold price (ie, between 2008 and 2014). Cases of malaria in all demographic groups showed a strong positive correlation with the gold price, but only in regions with mining camps (0·88 [95% CI 0·84-0·89] for boys and men aged between 15 and 50 years and 0·80 [0·73-0·85] for the aggregated population of women, children aged 12 years and younger, and adults older than 70 years). The highest correlation occurred earlier in men and boys aged between 15 and 50 years, the demographic most likely to be miners, suggesting that transmission in mining camps is followed by infections in the community. On the basis of these findings, we were able to reliably forecast P falciparum malaria trends using only the gold price as the predictor variable. A 1% increase in gold price was associated with a 2·13% increase in P falciparum infections after 1 month in the mining populations, and with a 1·63% increase after 2 months in the non-mining populations. Lastly, La Niña climatic events showed an additional, smaller positive correlation with malaria transmission.
Our analysis provides evidence that the P falciparum malaria surge observed in Guyana between 2008 and 2014 was likely to have been driven mainly by an increase in gold mining, while climate factors might have contributed synergistically. We propose that the international gold price over time is a useful indicator of malaria trends. We conclude that the feasibility of malaria elimination in Guyana, and in other areas in the Amazon where malaria and gold mining overlap, should be evaluated against the challenges posed by rapidly rising gold prices.
Ramón Areces Foundation, National Institutes of Health, and National Institute of General Medical Sciences.
2008 年至 2014 年间，圭亚那的疟疾发病率显著上升。由于没有证据表明国家疟疾控制策略受到损害，公共卫生当局将这一激增归因于森林地区金矿开采活动的暂时增加。然而，由于难以收集疟疾和采矿的可靠数据，因此缺乏对此关联的系统分析。我们旨在研究 2007 年至 2019 年间圭亚那国际金价与恶性疟原虫疟疾传播之间的关联。我们还旨在评估恶性疟原虫病例与厄尔尼诺-南方涛动模式之间的关联，此前有研究表明厄尔尼诺-南方涛动模式是疟疾的主要驱动因素之一。
我们使用圭亚那的国家疟疾监测数据，估计 2007 年至 2019 年间，国际金价与报告的 15 至 50 岁男性（即居住在采矿区且可能从事采矿活动的人）中恶性疟原虫感染之间的时间相关性。我们将这些估计与那些不太可能直接参与采矿活动的个体（即女性、12 岁以下儿童和 70 岁以上成年人）以及居住在非采矿区的个体的估计进行了比较。我们还评估了恶性疟原虫感染与同一亚人群和时间段内厄尔尼诺-南方涛动模式之间的相关性。最后，我们评估了一个统计模型的性能，该模型旨在使用国际金价作为预测变量实时估计恶性疟原虫感染。
在金价高峰期（即 2008 年至 2014 年），作为参与金矿开采的流动个体的临时居民中恶性疟原虫病例的比例最高。所有人群的疟疾病例与金价呈强正相关，但仅在有采矿营地的地区（15 至 50 岁的男孩和男性为 0.88 [95%CI 0.84-0.89]，女性、12 岁以下儿童和 70 岁以上成年人的综合人口为 0.80 [0.73-0.85]）。相关性最高的是在最有可能成为矿工的 15 至 50 岁男性和男孩中，这表明采矿营地的传播先于社区的感染。根据这些发现，我们仅使用金价作为预测变量，就能够可靠地预测恶性疟原虫疟疾的趋势。金价每上涨 1%，采矿人群中恶性疟原虫感染将在 1 个月后增加 2.13%，2 个月后在非采矿人群中增加 1.63%。此外，拉尼娜气候事件与疟疾传播之间存在额外的、较小的正相关关系。
我们的分析提供了证据，表明 2008 年至 2014 年间圭亚那观察到的恶性疟原虫疟疾激增很可能主要是由于金矿开采的增加所致，而气候因素可能起到了协同作用。我们建议，国际金价是疟疾趋势的一个有用指标。我们得出的结论是，应该根据金价的快速上涨所带来的挑战，来评估圭亚那以及亚马逊地区其他疟疾和金矿重叠地区消除疟疾的可行性。
拉蒙·阿雷塞斯基金会、美国国立卫生研究院和美国国立普通医学科学研究所。
