How do animals get the bubonic plague?

The bubonic plague is primarily spread by fleas that have fed on infected rodents (rats or mice). These fleas then transmit the plague bacteria (Yersinia pestis) to humans or other animals when they bite them. The bacteria can enter the body through the skin, usually through a flea bite or a scratch or cut on the skin that comes into contact with infected material, such as soil, water, or an animal carrying the bacteria.

When the infected flea bites an animal, the plague bacteria multiplies within the flea's gut. The flea's digestive system becomes blocked by the bacteria, causing it to regurgitate while biting, leading to the transmission of the bacteria to the animal.

Once in the animal's body, the bacteria can travel to the lymph nodes, where they multiply further, causing fever, swelling, and tenderness in the affected areas. This stage is known as the bubonic plague, characterized by the formation of swollen lymph nodes or "buboes" in the armpit, groin, neck, or other parts of the body.

Animals can become infected with the bubonic plague through various means:

1. Flea bites: The most common route of infection is through the bites of infected fleas that carry the plague bacteria. Fleas feed on the blood of rodents and other animals, including humans, and can transmit the bacteria while biting.

2. Contact with infected animals or their bodily fluids: Animals infected with the bubonic plague can transmit the disease through direct contact with their bodily fluids, such as blood, saliva, or urine. If a healthy animal comes into contact with these infectious materials, it can become infected.

3. Contact with contaminated environments: The plague bacteria can persist in the environment for long periods, especially in soil, water, or animal burrows. Healthy animals can become infected if they come into contact with contaminated soil or water or have access to infected animal burrows or nests.

4. Through the ingestion of contaminated food or water: In some cases, animals may also contract the bubonic plague by consuming contaminated food or water sources that have been in contact with infected animals or their fleas.

Rodents, such as rats, are common reservoirs of the plague bacteria and play a significant role in the transmission of the disease to other animals and humans. Fleas that feed on infected rodents can transmit the plague bacteria to other rodents, as well as to different animal species and humans who may come into contact with them.