Flea and Tick Pesticide Resistance and the Impacts on Dogs
Reports of acaricide/insecticide resistance were not discovered in fleas or ticks. Interests in insecticide resistance were just concepts entertained by Melander influenced by the thought of fruit-tree pests becoming resistant to sprays (“Vector resistance to pesticides,” 1992). Initially, insects of San Jose were treated with Sulphur-lime as concentrations were of a high efficacy against a wide variety of insects that were local to the area (Coles, T., 2014). While this information is evidential support for resistance studies, this information also provided the introductory knowledge of the difference in pesticide susceptibility in insects across varying geographical regions (Coles, T., 2014). Certainty regarding the influence of genetic resistance was not concluded (“Vector resistance to pesticides,” 1992).
In defining resistance, the World Health Organization (WHO) has coordinated information regarding standards measuring pesticide resistance by used of methods and resistance measuring testing kits (Coles, T., 2014). According to WHO, resistance is defined as the “development and an ability to tolerate toxicants which would prove lethal to the majority of individuals in a normal population of the same species” (WHO, 1957). The definition of resistance was later revised by WHO, “an inherited characteristic that impacts an increased tolerance to a pesticide, or group of pesticides, such as that the resistant individuals survive a concentration of compound(s) that would normally be lethal to the species” (“Vector resistance to pesticides, “1992). A consistent definition of varies based on topical preferences of scientific literature.
Regarding the primary cases of tick and flea pesticide resistance, mosquitos were being used as preliminary biomarkers in resistance studies when they began to show resistance to DDT (“Vector resistance to pesticides,” 1992). Along with mosquitoes, house flies also exhibited resistance to DDT use in Italy, in the 1940s (Coles, T., 2014). When fleas (cat fleas, Ctenocephalides felis, specifically) began to start showing resistance to DDT in 1952, ticks were soon to follow two years later. Dieldrin and benzene hexachloride were ideally the first pesticide compounds the fleas and ticks began to show resistance to before DDT (Coles, T., 2014). With this continual report of resistance, the more the concern of controlling pests begin to arise.
Nonetheless, understanding the evolution of resistance is necessary to understand the occurrence of resistance in fleas and ticks. People that have genetic traits that allow for survival against pesticide/acaricide exposure will most likely pass on genes to next generation (Coles, T., 2014). When this passing of genetic pesticide resistance DNA occurs, the potential of resistant populations increases each generation that the gene is passed down to (Coles, T., 2014). Thus, increasing survival rates of pesticide chemical susceptibility. There are three phases necessary for successful resistance evolution. In the first order for evolution to succeed, people of a group must possess differentiating genetics, Next, phenotypic differences must occur in differentiating genetics (Coles, T., 2014). Finally, differentiating phenotypes have to encourage survivability so that there is a capable transference of resistance in the succeeding generation (Coles, T., 2014).
Genetic resistance occurs naturally by way of mutations and recombination and with the help of constant pesticide use, eliminating insects without resistant genes provides a new selection for the subject with resistant genes (Coles, T., 2014). Without genetic mutation, resistance to pesticide would not evolve. As dog ticks require three hosts because it feeds on dogs in all stages of its life. As the development occurs on the host, the exposure to three different concentrations or pesticide types on the dogs these fleas and ticks are increasing the chances of genetic evolution at each stage (Dryden, M., 2009). Pesticides do not cause resistance but allow a weeding out the resistant because all of the non-resistant genes have been killed off (Coles, T., 2014).
On another note, fleas can live on a dog host from egg through an early adult stage. Even if the dog is treated with insecticide, fleas can obtain a new host in the surrounding environment of the dog (“Vector resistance to pesticides,” 1992). Resistance to pesticides can also be due to inconsistent use by the owner. When a pesticide application is not consistent, shelf-life is not up-to-date, or there is an inappropriate use of the application (not as instructed use), the lack of efficacy can be viewed as resistance (Coles, T., 2014). In addition, resistance may be due to a treated dog coming into contact or the environment with flea-infested wildlife which would result in seemingly fails of infestation control measure or resistance of ticks and fleas (Coles, T., 2014). Rhipicephalus sanguineus are common dog ticks that feds on various of dogs during and after molting stages. To avoid the use of a chemical pesticide on dogs with fleas and ticks that are susceptible to resistance to eliminate or reduce risks of further resistance (Coles, T., 2014).
As fleas and ticks become increasingly susceptible or resistance to pyrethroid treatments in dogs, controlling infestations will become harder to eliminate spread to animals in surrounding environment. Typically, there is an apparent awareness of possible infestation occurring on dogs as they are brought to Veterinarians when clients are making multiple complaints and appointments about fleas and tick occurrences. A resistance of pesticides in fleas in ticks can have many problematic impacts in dogs. When dogs are being exposed to vast flea and tick populations, allergy dermatitis or hypersensitivity are the most common effects of a dermatologic disease (Dryden, M., 2009). Skin diseases can come from constant exposure to pesticides in treating resistant fleas and ticks which as a result causes mild to severe skin irritations to develop. Not only does the skin disease derive from repeated harsh chemical exposure but can derive from an increase of irritants produced by infestation for untreatable fleas and tick. Such irritants can include bites, saliva, urine, feces, inhaled exposure to particles that are infectious aerosols (Moriello, K., 2003).
Concerning the lack of insecticide/acaricide alternatives has also been a contributing factor in resistance to pyrethroids. However, the use of an organism that kills arthropods as biological control was studied to be effective and successful in the entomologic applications of ticks and flea treatment. Regarding the use refugia management which involves “avoiding chemical use a susceptible proportion of individuals (Coles, T., 2014).” Despite this option, Veterinarians do not recommend the use of non-chemical treatments against ticks and fleas in dogs. Instead, Veterinarian suggests owners implement and maintain periodical insecticide treatment in dogs as well as in the home for best results. With regards to vaccinating dogs as a prevention treatment against flea and tick exposure, there are not any vaccinations available currently (Coles, T., 2014).
All in all, resistance in pesticide used as pest management against ticks and fleas in domestic animals such as dogs is becoming a growing concern. Data implications centering around the impacts on how such a development as this can negatively impact dogs lacks sufficiency. The only know impacts of resistance of pesticides in fleas and ticks includes the development of skin diseases due to extreme irritations. Such irritants can derive from flea and tick infestation, excessive chemical treatment use on the infested dog, or from both factors.
Flea and Tick Pesticide Resistance and the Impacts on Dogs