Association of soil chemistry and other factors with spatially distributed Burkholderia mallei DNA in Punjab province, Pakistan

Association of soil chemistry and other risk factors with soil borne Burkholderia mallei (B. mallei) DNA in eight districts (Sheikhupura, Gujranwala, Faisalabad, Sargodha, Chakwal, Attock, Sahiwal, Dera Ghazi Khan) of Punjab province, Pakistan, was studied. A total of 22 soil samples (n=11, each from soil positive and negative for B. mallei DNA) were processed for chemical analysis from B. mallei positive districts (Sheikhupura and Chakwal). The relationship between soil composition, absence or presence of the pathogen was ascertained. In soil samples of Chakwal district, DNA of B. mallei was found to be highly associated with 0.80 to 39.20% range of moisture contents (p=0.008) and 1.74 to 21.75 mg/Kg of P (p=0.050). The association in Sheikhupura district was with sodium (1.90 to 133.59 mg/Kg; p=0.018) and moisture (0.80 to 39.20%; p=0.026). The odds of detecting DNA of B. mallei was 1.4, 6.8, 5.0, 2.8 and 10.6 higher when soil sample sites were < 500 meters from vehicular traffic roads, < 01 km from animal markets, < 100 meters from canal, < 1000 animals and < 300 houses/village, respectively. While the odds of detecting DNA of B. mallei were 0.1, 0.3, 0.4, 0.2 and 0.5 when soil sample sites were > 500 meters from vehicular traffic roads, > 01 km from animal markets, > 100 meters from canal, > 1000 animals and > 300 houses/village. Soilborne B. mallei DNA is more likely to be detected in areas closer to roads having vehicular traffic along with interstate routes and soil containing low levels of moisture.