Climate change and its influence on occurrence and distribution of Anthrax in Bangladesh

Abstract

Background: Anthrax is a serious infectious disease of human and animals. It is caused by the gram positive spore forming bacteria Bacillus anthracis. This study assessed the interrelationship between climate change and occurrence of anthrax outbreaks in Bangladesh. Methods & Materials: Meteorological daily data from 35 meteorological observatory stations across the country were collected from Bangladesh Meteorological Department, Dhaka and anthrax outbreak data were collected from Department of Livestock Services (DLS), Bangladesh from 2010 to 2014. The data were entered into a spreadsheet program (Excel 2007, Microsoft) and transferred into STATA/SE 13.0 for data analysis. Descriptive statistical analysis, Pearson correlation and regression analysis were applied. Results: The highest monthly outbreak number was 1,100 in September 2013 and the second highest was >800 in May 2010. The average, maximum and minimum temperature were recorded as 26.02333, 30.1 and 16.8 °C; humidity were 79.82%, 87.4% and 67.9%; rainfall were 5.988333, 19.5 and 0 mm; cloud coverage were 3.47, 6.5 and 0.6 h/day and wind speed were 2.45 knot, 3.9 knot and 1.4 knot, respectively over the country. There was a significant positive correlation (p < 0.05) among the outcome series and temperature (°C), rainfall (in mm), cloud coverage (in hour) and wind speed (knot). In case of temperature (°C), predicted anthrax outbreak = −130 + 14.836X temperature. When temperature increases by 1 °C, anthrax outbreak increases by 14.836. There was a peak of outbreaks each year in the summer and rainy season, March to September. Predicted anthrax outbreak for rainfall (in mm) = 199.4629 + 9.452X rainfall; for cloud coverage (1 h/day) = 128.75 + 36.69X cloud coverage and for wind speed (knot) = −6.0879 + 107.0X wind speed. When rainfall increases by 1 mm, cloud coverage increases by 1 h/day and wind speed increases by 1knot, anthrax outbreak increases by 9.452, 36.69021 and 107.0019, respectively. Conclusion: The results of the present study showed that increasing the ambient temperature and the occurrence of heavy rainfall as well as cloud coverage and wind speed acceleration in the monsoon season significantly contribute to the anthrax outbreaks in Bangladesh.