Pago Pago, AMERICAN SAMOA — Dog and Cat owners are aware of the itchiness, hair loss and red rashes that happen with fleas, especially when the animal is allergic to flea bites.  Fleas can do a lot more damage than that.

Plague is caused by a bacteria carried and transmitted by fleas.  This disease has several forms, all capable of causing severe illness or death in people and animals.  There is even a vaccine used in dogs and cats in some regions of the world where the disease is a real problem.

Remember it is the flea carrying the disease not the cat or dog.

A new study published October 2023 looked into what other diseases are carried by fleas.  Their source of fleas was free-roaming cats.  They found multiple bacterial species, which can be harmful to animals and people.  Over the past hundred years or so research is slowly accumulating as to the diseases these pests carry.

The cat flea is a species of flea — it does not mean the flea you see on your cat — but confusingly is one of hundreds of flea species, and is called ‘cat flea’.  It happens to be the flea type commonly found on dogs as well.  However, we call these reddish brown, fast moving or hopping external parasites just plain ‘fleas’.  

Optimal environment for the flea life cycle is 27-32 degrees Celsius and 75-90% relative humidity.  Tropical weather like our weather here in American Samoa.

The flea generally stays with the animal for its adult life with females laying eggs,which quickly fall off into the surrounding environment.  If they fall into a good place undisturbed by vacuum or broom they will hatch and progress eventually to an adult.  Knowing this part of the life cycle helps you to control the flea populations on your animals.

Control those eggs, larvae and pupae in the environment by sweeping or vacuuming especially cracks and crevices, and frequent laundering of rugs, mats and bedding.  On the animal use flea combs and kill adults you capture in the comb.  Here you can put a few drops of garden insecticide with a bit of water in a container and toss the fleas you capture in the container.  Chemicals not intended for animals should not be used for animals.  This includes kerosene and other garden chemicals.

The pupa form is very difficult to kill with any chemical so generally they will need to hatch first.  The adult hatches from the pupa form and quickly searches for a blood meal.  If there are no animals they will not turn down a meal from a human.

At the adult stage, which is quickly on the animal, methods to kill adults become necessary and include previously mentioned flea combing and bathing with shampoo such as flea shampoo.  Other products safe for animals include oral and topical forms of chemicals.  These should be used sparingly, as needed, to minimize environmental risks, and to minimize resistance building.

Resistance happens when parasites are exposed to a chemical over some period of time. Those that don’t die pass on the genetic ability to resist death from this chemical to their offspring. Pretty soon that chemical is not working like it used to. Resistance can happen pretty quickly in a lifecycle which can be just one month to the next generation.

Interesting that a healthy adult cat can reduce its flea population by 50% with grooming — which explains why we see more fleas on very young and very old or sickly cats as their grooming habits are greatly reduced.

One Health idea was to really get into the mindset of people how animals, the environment and people interplay. The details about fleas, life cycle and disease illustrates this. One of the most important things to learn about how nature does things as opposed to how humans do things is biodiversity. The more we overpopulate with cats and dogs, for example, the more we concentrate problems.  As we are finding out on many levels we start to have some very human issues in trying to deal with such dilemmas.  

Fleas carry some worrying agents of disease… be biodiverse in controlling their populations.