Abstract:

Malaria is an insect-borne infectious disease transmitted by anopheles. It was widespread in China about 3,000 years ago and continues to pose a severe threat to human life and health. Taking the Malaria epidemic during the Qing Dynasty as the research object, and using Excel, Geographic Information System (GIS), MaxEnt, and BounderSeer, the following results were obtained: 1) Malaria was one of the most common diseases during the Qing Dynasty. During fifty-nine of the total of 268 years of the Qing Dynasty, Malaria was widespread, with a frequency of 22.01%. The disease spread to 17 provinces, leading to an epidemic situation in a total of 210 counties, covering an area of 340,400 km². This area accounted for approximately 2.69% of the total malaria-epidemic area during the Qing Dynasty. Malaria outbreaks frequently during the seasons of autumn and summer. These two seasons account for 85.23% of the total pandemic years and 92.47% of the pandemic-struck counties. Consequently, autumn and summer are targeted for the prevent and control of the Malaria pandemic. 2) Genetic adaptations to Malaria parasites is highly adaptable in China, with the southeast being the most optimal place for the mosquitoes to thrive. As per the distribution pattern, the risk of Malaria decreases from the southeast to northwest, of which, the Jiangsu, Anhui, Shandong, Henan, Hubei, and Hunan provinces have higher risks of Malaria. Various environmental factors affect the prevalence of Malaria with altitude, minimum temperature, and annual temperature difference as the main factors, with respective contribution rates of 44.4%, 16.3%, and 10.6%. 3) The geographical boundaries of Malaria were clearly established. The Malaria epidemic during the Qing Dynasty presented the boundary characteristics of "two horizontal and three vertical." The first horizontal boundary at the 40°N line and the second at the Nanling line were, respectively, the northern boundaries of Malaria and falciparum Malaria (pestilence). The first vertical boundary was an arc with Huoshan at its center. Using the straight-line distance between Huoshan and Hongya (approximately 1,250 km) as the radius, this area accounted for 96.67% of the Qing Dynasty Malaria pandemic. The second vertical boundary was the boundary line of the highly adaptable area of the Malarial mosquito, which included the eastern and central provinces of China. The third vertical boundary was the enclosure area based on the main Malaria network, covering the Yangtze River Delta region. However, the risk levels and boundary characteristics of the Malaria pandemic were not invariable and changed based on the natural and social environments. For example, the high-risk Malaria-endemic areas of the Qing Dynasty included Hubei and Hunan, with lower levels of risks in Sichuan, Yunnan, and other provinces, which still continue have low levels of risk. Investigating the temporal and spatial characteristics, risk levels, and boundary characteristics of the Malaria epidemic during the Qing Dynasty is expected to provide a historical basis for the improvement of the present Malaria control system, as well as a historical reference for dealing with sudden Malaria outbreaks.

Key words: Malaria, Spatial-temporal characteristics, danger simulation, boundary detection, Qing Dynasty (16441911)