BRAZILIAN AMAZON — A study published in the journal Communications Earth & Environment identified patterns of vector-borne disease co-occurrence in the Brazilian Amazon between 2015 and 2019. Researchers aggregated data from this period to analyze connections to agrarian economy and socioenvironmental factors.

From 2015 to 2019, 1.28 million cases of vector-borne diseases were reported across the Brazilian Amazon. Malaria accounted for 75% of these cases, while dengue represented 20.1%. Rural areas experienced higher notification rates for Chagas disease, malaria, and American tegumentary leishmaniasis, whereas urban areas had higher rates of visceral leishmaniasis.

The study found that Chagas disease and malaria frequently co-occurred, as did dengue and American tegumentary leishmaniasis. Visceral leishmaniasis was observed to be isolated from other vector-borne diseases. High deforestation rates and rural multidimensional poverty were associated with the co-occurrence of both urban and rural Chagas disease within municipalities.

Mining activities, rural multidimensional poverty, and forest core areas were shared factors associated with the presence of Chagas disease and malaria in both urban and rural settings. Large-scale agriculture, forest core areas, and pasturelands were also shared associated factors for dengue and American tegumentary leishmaniasis. Municipalities without both malaria and Chagas disease were largely characterized by cattle ranches and extensive agriculture.

A hotspot for Chagas disease and malaria was identified in the Western Amazon region. Minor hotspots for these two diseases were found in northeastern areas of the Brazilian Amazon, where mining activities and forest cover are predominant. In contrast, the southeast Amazon region, characterized by economies based on grain production and cattle ranching, was a cold spot for malaria and Chagas disease.

Forest-linked peasant economies often correlated with a higher reported incidence of Chagas disease and malaria. Eighty-eight percent of municipalities within the malaria-Chagas disease cluster were dominated by peasant-based agriculture and peasant agroforestry. The southeast Amazon region also displayed a large hotspot for dengue and American tegumentary leishmaniasis, with 97% of municipalities in this cluster dominated by livestock farming and agricultural exports. Municipalities with ranching activities and large-scale farming were strongly associated with visceral leishmaniasis.