Impact of Temperature on Tuberculosis estimated from Satellite Remote Sensing before and during COVID-19 Pandemic

Several epidemiological studies have examined the effect of temperature on health, such as tuberculosis (TB). Previous researches have used temperature data from local station sites but the temperature in an area is spatially variable. For example temperature in the urban area is normally higher than in the rural area because of the urban heat island. Satellite remote sensing data can provide area information and is, therefore useful to quantify the effect of environmental hazards on health in a wider region. To study the impact of temperature on TB, this study estimates Land Surface Temperature (LST) using Landsat 8 data in Yogyakarta City, Indonesia from 2016 to 2020 and analyzes the relationship between temperature and TB cases. The LST estimates were first verified by the temperature data obtained from the Meteorological, Climatological, and Geophysical Agency. Tuberculosis cases from 2016 until 2020 were collected from Public Health Office. The correlation patterns have also been examined before and after the COVID-19 pandemic. The result shows that the satellite-derived LST reasonably matches the ground measurement, and a negative correlation between TB cases and LST can be recognized: the cases number is higher in low LST while the cases number is lower when LST is higher. This can be explained that the increase of TB case number in the lower temperature is because ultraviolet radiation kills bacterium, which impedes the spread of TB in dwellings. However, this correlation cannot be observed after COVID-19 outbreak. The number of TB cases in 2020 (during COVID-19 pandemic) is generally lower than the previous year (2016-2019, before COVID-19 pandemic) in the study area. This study suggests that social restriction policy may potentially affect the spread of TB and thus shows the irrelevant relationship between LST and TB cases during COVID-19 pandemic.