Fleas: between us and pets
Technical note on fleas: between us and pets, with a focus on diagnosis, prevention and criteria applicable to professional pest management.
Fleas are insects belonging to the order Siphonaptera. Approximately 1,400 species belong to this order. The families Hectopsyllidae, Pulicidae and Dolichopsyllidae are the most representative. Its biting-sucking mouthparts are adapted to lacerate the skin and suck blood. Although they lack wings, fleas can move easily thanks to their ability to jump.
Once sexual maturity is reached, between 18 and 24 hours, males and females copulate on their host and the female begins to lay eggs. The eggs are 0.5 millimeters, ovoid and pearly white. Depending on the species, a female can lay between 500 and 800 eggs in her entire reproductive life. They lay 13 to 25 eggs per day, with maximum peaks of 40 to 50 eggs per day.
The eggs, unlike those of lice, are not attached to the hair and fall from the host. After 1 to 12 days they hatch and a blind, legless larva emerges from them. These larvae breed in the environment, quickly escape light and feed on detritus and fecal matter, dehydrated blood, of adult fleas.
Between one and twelve days, depending on the conditions of temperature, humidity and food, three larval stages pass. The last larva, 4 millimeters long, spins a silk cocoon, giving rise to the pupa. During this state, the insect remains motionless and without feeding until all its structures are developed.
Once developed, the adult, 1.5 to 3 millimeters depending on the species, can remain up to two years inside the puparium waiting for its host. Once emerged, the adult flea should receive its first blood meal within the first 24 hours; otherwise he will die. The resistance they possess in the pupal state is what allows them to complete their life cycle in two weeks or two years. However, under controlled temperature and humidity conditions inside homes, the cycle is usually completed in approximately 18 days with an adult life of 30 to 40 days.
Parasitic insects often cause direct and indirect damage. Among the direct damages we can mention bites. Fleas feed for 10 to 15 minutes, they are intermittent parasites and have discontinuous feeding habits. Depending on the degree of susceptibility of the host, they could develop some significant dermatitis.
As indirect damage we must consider the transmission of diseases. Fleas can transmit bubonic plague, rickettsiae and cestodes. These diseases are transmitted through what is known as pest transmission mechanism.
Most common species
The most representative family of the order is the Pulicidae. First of all we find Pulex irritans, or man's flea. It lacks a pronotal and genal comb. It has an ocular spine inserted in front of the eye. It is a species widely distributed throughout the world and is frequently found on humans, although it can appear on dogs, cats, pigs and wild animals. It is an important vector of cysticerci such as Dipylidium caninum.
Another important species is Xenopsylla cheopis, rat flea. It lacks a pronotal and genal comb, but is differentiated from the man flea by having an ocular spine inserted under the eye. Through its bite it transmits Yersinia pestis, pathogen that causes bubonic plague.
Without a doubt the most frequent fleas in urban areas are Ctenocephalides canis and Ctenocephalides felis, dog and cat flea respectively. Both species have a genal and pronotal comb, although in C. canis The first spine is shorter than the second. Furthermore, the head of the dog flea is short and tall, quadrangular, while that of the cat flea is shorter and elongated, almost oval. They can be found parasitizing humans, weasels, foxes and other wild animals.
Integrated management
The basic pillars of integrated management are represented by inspection, cultural control, physical control and finally chemical control. All these tools used judiciously and rationally tend to generate a synergism that culminates in more effective controls.
There are concepts that should not be forgotten when proposing a strategy. The immature stages, eggs, larvae and pupae, are found in the environment and represent 95% of the population. The larvae are extremely lucifugal and hide in cracks, baseboards and other shelters. Pupae, a resistant state, can reach two years in the environment before parasitizing a host. When the host dies, the adult fleas descend from it and in the environment can tolerate up to a year without feeding. Depending on the species, a flea can generate between 500 and 800 eggs in its thirty to forty days of adult life, and the highest proportion of eggs is usually found in pet resting places.
Inspection
It is extremely important to dedicate time to this first stage. The success of the control strategy will depend mainly on the detection of active zones. Adult insects suck blood and defecate dried blood. This fecal matter is dehydrated and appears dark, black to the naked eye, and is solid to the touch.
To obtain these excreta, the pet's hair must be combed, preferably on a white surface. The eggs and larvae are observed with the naked eye or with a hand-held magnifying glass. Flea larvae can be found far from their birthplace as they move at a rate of thirty centimeters per minute escaping light.
Cultural and physical control
Educating the client always brings extremely effective results. At the same time, it is a good way to demonstrate suitability and knowledge regarding the subject for which we have been hired. Emphasis should be placed on cleanliness, this will prevent the environment from becoming a favorable place for the development of immature stages.
Frequent vacuuming minimizes the presence of nutritional detritus, eggs, larvae and pupae. Whenever possible, inside the house, it is advisable that there is only one place for animals to sleep. This will avoid multiple active sites or sources of reinfestation. Contact with neighboring animals and mainly stray animals should be avoided.
Without a doubt, the pest control professional's best friend is the vacuum cleaner. Carrying out specific aspirations in pet resting places, baseboards and carpets significantly reduces population density. In turn, detritus and fecal matter from adult fleas are removed, which serve as food for the larvae. Good aspiration also significantly reduces the presence of pupae, adults in a dormant state, in the environment.
Once the use of the equipment is completed, the retention bag or container must be removed and placed in a nylon bag. This bag must be sealed and placed in the freezer for at least 24 hours. This practice is essential to avoid the survival of the aspirated individuals.
Chemical control
Finally, the tool appears that guarantees a certain residuality in the integrated management program. The chemical treatment of the animal and the environment must be coordinated and simultaneous.
To control adult insects on animals, pipettes containing fipronil as an active ingredient are usually used. In this way we will be trying to eliminate 5% of the existing population, without losing sight of the fact that this low percentage of adults is the one responsible for producing offspring. Ideally, the veterinarian should carry out the treatment on the animal about 48 hours before carrying out the environmental treatment.
The targeted application of adulticidal and/or larvicidal products will allow us to control eggs and larvae that may be hidden or protected in places where we do not have access. Today there are dual formulations that contain growth regulators to control immature stages and insecticides to control adults. These active ingredients also exist separately and one can adjust the appropriate usage proportions.
Applications can be specific, in rest areas, baseboards and transit places, or spatial misting, depending on the possibilities and type of area. The residual effect of insecticides on flea control is questionable; Therefore, it is essential to consider that control will be through direct contact during applications.
Between applications it should be inspected to confirm if reapplication is necessary. If so, applications should be made every 7 days for 3 weeks. Remembering that fleas abandon their hosts once they are dead, at the end of rodent control it is important to carry out a dual preventive application for flea control.