Making the world better, one answer at a time. Rich soil is made up of sand, silt, clay and organic matter (compost) in various stages of decomposition. Humus is the stable remains of decayed organic matter, carbon remains of unknown sorts that attach themselves to clay to improve soil structure. Humus has the ability to increase the soil's water retention, buffer PH , and helps the plant use nutrients although humus is not fertilizer but humic acids and humins.
Salmonellosis, or salmonella, is another bacterial illness that both domestic and wild rats carry. Like leptospirosis, it is spread to humans through contact with urine and feces. In humans, salmonellosis causes gastrointestinal problems such as diarrhea, stomach cramps and fever.
Plague is an infection caused by the bacterium Yersinia pestis. The bacteria are found mainly in rats and in the fleas that feed on them. People and other animals can get plague from rat or flea bites. In the past, plague destroyed entire civilizations.