Abnormal swelling or growth in any part of the body. The term notably appears in 1 Samuel 5–6. The Philistines took the ark of God from Israel. Soon after, a deadly and painful disease spread through the Philistine city where they kept it. The disease was associated with the presence of rats (1 Samuel 6:4–5). The signs of this disease match what we now call the bubonic plague.
In bubonic plague, the fleas of the rat transmit the bacteria Yersinia pestis to humans. The bacteria invade the human body. They cause fever and buboes, which are large, soft swellings in the armpit and groin. Without treatment, 6 to 9 out of every 10 people who got the disease would die. The Philistines sent the ark of God back to Israel. With it, they sent offerings made of gold that looked like rats and tumors (1 Samuel 6:11, 17–18).