Rat fleas may not be as common as cat or dog fleas, but they are important vectors of deadly diseases, such as the bubonic plague. In fact, rat fleas are believed to have killed nearly a quarter of the European population in the 14th century by spreading bacterium called Yersinia Pestis, responsible for the infamous ‘black plague’.
Rat fleas are of two types. The Northern rat fleas, or the Nosopsyllus Fasciatus, predominantly infesting rodents, rats, mice and other small animals (wild squirrels, chipmunks, prairie dogs etc.) in the US and Europe. The second variety is the Oriental rat flea (Xenopsylla Cheopis), which is the more common human plague vector.
Rat flea life cycle
Both Xenopsylla Cheopis and Nosopsyllus Fasciatus begin life as small white eggs, typically found around animal bedding and rat dwellings. The larvae that hatch from the eggs are approximately 2.5 to 3 mm long. They do not drink blood like the adult Xenopsylla Cheopis or Nosopsyllus Fasciatus, rather they survive on flea droppings, animal hair etc. This is followed by the pupa stage. The pupa emerges from the cocoons as adult rat fleas, capable of drinking blood from animals and humans.
Plague from the Nosopsyllus Fasciatus and Xenopsylla Cheopis in the United States
In the US, plague is commonly seen in areas near the western grasslands and the scrub woodland regions in states like Arizona, Colorado, New Mexico and Utah. Plague pathogen is transmitted to humans in the following ways:
- The infected rat fleas search for other sources of food when host rats are few in numbers. Humans and pets in the vicinity of infected rats or dead mice are more likely to get bitten by infected rat fleas.
- Pets that romp freely outdoors are also likely to bring infected Nosopsyllus Fasciatus or Xenopsylla Cheopis fleas into the home. Exposure to infected rat fleas can give rise to primary bubonic plague or septicemic plague.
- Coming in direct contact with fluids of infected animals (especially in case of hunters or butchers) without following proper meat handling precautions is another way of catching bubonic plague.
- Cats which eat infected or dead rodents can also come in contact with infected rat fleas and get sick with the disease, which they can then transmit through droplets to their owners or vets.
Symptoms and treatment of rat flea bites
The first sign of infection from rat flea bites is swollen painful lymph glands. Bubonic and systemic plagues are both very serious diseases and medical help must be sought immediately. Sometimes, owing to lack of symptoms, the only way of diagnosing plague is through a blood/lab test. Once plague has been diagnosed, appropriate treatment and quarantine procedures need to be followed.
Preventing rat fleas
Prevention is the best way of controlling spread of plague from rat fleas.
- It is essential to reduce rodent and rat dwellings. For this, you must remove garbage, clutter, wood piles and other possible rat food sources from around the home. Residential areas, office buildings, schools and day care centers should be made rodent proof.
- It is important to wear gloves when treating or skinning small animals, squirrels, etc. All meat handling precautions must be followed by hunters and butchers in order to prevent diseases through infected fluid transmission.
- Rat fleas are common in camping sites, places of hiking, trekking etc. Flea repellents must be used when engaging in such activities. Many FDA approved products like DEET and permethrin are safe to be applied to pets and humans. When using these products, all safety precautions mentioned on the labels must be followed.
- It is important to keep rat fleas off the pets. Flea infected pets must be promptly treated with vet approved products.
- Pets that are free to roam outdoors are more likely to come in contact with infected rat fleas. At the first sign of sickness in such animals, it is important to seek medical help immediately. It is also essential to prevent pets from sleeping on your bed, especially when living in endemic areas.