Fleas

Several flea species are found in Thailand, with the cat flea (Ctenocephalides felis) being the most common household pest despite its name, as it readily infests both cats and dogs. Other species include the dog flea (Ctenocephalides canis), human flea (Pulex irritans), and oriental rat flea (Xenopsylla cheopis). The latter is particularly concerning as a vector for diseases like murine typhus and bubonic plague, though these diseases are rare in modern Thailand.

Fleas undergo complete metamorphosis with four life stages: egg, larva, pupa, and adult. Adult female fleas lay eggs on host animals, but these eggs fall off into the environment where they hatch into larvae. The larvae feed on organic debris and adult flea excrement before spinning cocoons and pupating. The pupal stage is particularly resistant to insecticides and can remain viable for months waiting for suitable conditions. Adult fleas emerge from pupae in response to vibration, heat, or carbon dioxide, indicating a potential host nearby.

Flea bites typically cause small, red, itchy welts often grouped in lines or clusters. Beyond the discomfort of bites, fleas pose several health risks. They can transmit tapeworms to both pets and humans, and some people and animals develop flea allergy dermatitis, a severe allergic reaction to flea saliva. Heavy infestations on pets can cause anemia, particularly in young or small animals. While less common in Thailand today, fleas have historically been vectors for serious diseases like plague, typhus, and bartonellosis.