Biomedical subjects

M W Dryden

Publications and source records attributed to M W Dryden.

32 records · Page 2Linked to original sources

PubMed1999

Susceptibility to insect growth regulators and cuticle deposition of the cat flea (Siphonaptera: Pulicidae) as a function of age.

Wandering larval, pharate pupal, pupal, and pharate adult stages of the cat flea, Ctenocephalides felis (Bouché), were identified by examination of cuticular cross sections via scanning electron microscopy. Visible morphological characteristics of each stage were identified and described. Various stages of the flea throughout metamorphosis were exposed to juvenile hormone mimics and insect developmental inhibitors. Wandering larvae treated with juvenile hormone mimics were unable to pupate, whereas treated pharate pupae ecdysed to the pupal stage but were unable to enclose. Pupae and pharate adults did not succumb to juvenile hormone mimic exposure, even at concentrations 3 orders of magnitude greater than those that killed 100% of the wandering larvae and the pharate pupae. Adult females were more susceptible to juvenile hormone mimics than males. Possible explanations for the variation in tolerance to juvenile hormone mimics of the differing stadia are discussed. None of the stages were susceptible to insect developmental inhibitor exposure. Analysis of catecholamines that are precursors of cuticle sclerotization and melanization were measured in the wandering larval through the pharate adult stages of the cat flea. N-acetyldopamine concentration was highest in the pupa stage when the flea had a hard, clear cuticle; N-beta-alanyldopamine concentration was highest during the production of the hard, dark cuticle of the pharate adult; and dopamine fluctuated throughout development but was highest in the pupal stage.

Animals↗

PubMed1997

The biology, ecology, and management of the cat flea.

The cat flea, Ctenocephalides felis felis, is the most important ectoparasite of domestic cats and dogs worldwide. In addition to its annoyance to pets and humans, C. felis felis is responsible for flea bite allergy dermatitis and the transmission of dog tapeworm. The abiotic and biotic factors that affect the development of immature stages are reviewed with special emphasis given to those aspects directly affecting control. Factors influencing host selection and feeding by adults are summarized. Recent studies concerning mating and oviposition, especially as they impact the likelihood of survival by immatures, are discussed. There has been an increase in the number of reports of insecticide resistance in the past ten years. Greater attention has been placed on disrupting larval development in modern IPM programs. The immature stages of the cat flea are extremely susceptible to environmental factors such as temperature and relative humidity and insect growth regulators (IGRs). In recent years, the control of cat fleas has increasingly relied on the use of IGRs applied to the host or to the indoor environment. Finally, we discuss advances in pesticide chemistry that provide tools for better control of adult fleas on the host.

Animals↗

PubMed1996

Insecticide susceptibility of cat flea (Siphonaptera: Pulicidae) pupae.

Studies were conducted to investigate what protective nature the cocoon and nylon carpeting has against the performance of insecticides directed at cat flea, Ctenocephalides felis (Bouché), pupae developing in carpet. The following 5 combinations of life stages and substrates were used in these tests were: (1) larvae that pupated in carpet, (2) cocoons placed in carpet, (3) naked pupae placed in carpet, (4) cocoons placed on filter paper, and (5) naked pupae placed on filter paper. These studies evaluated the performance of chlorpyrifos, microencapsulated chlorpyrifos, propetamphos, permethrin, and linalool. When averaged over all insecticides, the mean controls of cocooned pupae placed in carpet and cocooned pupae placed on filter paper were 37.2 and 26.7%, respectively, whereas that of naked pupae placed in carpet was only 13.7%. Additional tests conducted using chlorpyrifos revealed that mortality was 23 and 42% higher, respectively, whenever pupae in cocoons and naked pupae were treated in glass dishes without filter paper. These studies demonstrate that the debri-coated cocoon is not a barrier to insecticide penetration, and that pupae appeared to be protected inside the carpet matrix. Additional studies demonstrated that control of pupae developing in carpet was maximized at lower application pressures. The mean control of pupae with chlorpyrifos at 0.7 kg/cm2 pressure was 77.2%, yet applications at 1.7 kg/cm2 resulted in only 23.3% control.

Animals↗

PubMed1994

The cat flea: biology, ecology and control.

Control failures and recurrences of infestation of dogs, cats and their home environment with the cat flea, Ctenocephalides felis felis are common. Attempts to control these infestations are often impaired by an inadequate understanding of the interaction of the cat flea with its hosts and environment. This review presents information on the medical and veterinary importance of the cat flea and discusses recent information on the environmental and host factors that affect its development and survival. Additionally, information is presented on the use and effectiveness of various insecticides and insect growth regulators against the four life stages.

Animals↗

PubMed1994

Cat flea (Siphonaptera: Pulicidae) cocoon formation and development of naked flea pupae.

The rate of cat flea, Ctenocephalides felis (Bouché), pupal development and the stimuli responsible for successful cocoon formation were investigated by rearing flea pupae without an enclosing cocoon. Female larvae pupated an average 12.1 h earlier than males, and female pupae developed to the adult stage an average 1.6 d earlier than males. When larvae were not allowed to orient against a perpendicular structure, only 2.2% of these larvae were able to spin an enclosing cocoon. Although these naked flea pupae had no enveloping cocoon, 96.5% survived to become adults. Gentle sifting of the larval medium 0-12 and 12-24 h after cocoons were formed resulted in 13.7 and 3.5% of the larvae emerging, respectively. Over 40% of those larvae did not spin a second cocoon, but developed as naked flea pupae.

Animals↗

PubMed1994

Techniques for estimating on-animal populations of Ctenocephalides felis (Siphonaptera: Pulicidae).

Effectiveness of two sampling techniques to estimate cat flea populations were compared on beagles (short-haired dogs). Overall, 23.5 and 81.6% of known flea populations on the beagles were detected using area and comb counting techniques, respectively. Using comb counts, we were able to differentiate among beagles that were infested experimentally to produce densities of 21.6 (low), 42.2 (medium), and 82.5 (high) fleas per dog. Using the area counting technique, we were able to differentiate between the medium and high flea population groups, but not the low- and medium-density groups. A weighted regression analysis gave prediction intervals for flea densities that provided satisfactory estimates of the actual numbers of fleas on the dogs.

Animals↗

PubMed1994

Vaccination against the cat flea Ctenocephalides felis felis.

Non-chemical control of haematophagous parasites is a desirable goal. We report here on the use of concealed antigens from the major digestive organ of the cat-flea as vaccine components. Rabbits were immunized with various antigens from cat flea midguts, and immunoglobulin from these rabbits was fed to cat fleas in an artificial feeding system. Antibody produced against soluble antigens from the midguts of fed fleas was able to kill fleas in this system. Dogs were then immunized with various antigen preparations, and challenged for a week with live fleas. Significantly fewer live fleas were recovered from dogs immunized with fed midgut supernatant, and recovered live female fleas produced significantly fewer eggs. This study indicates the possibility of vaccination as a means of control of flea, and possibly other blood sucking insect populations.

Animals↗

PubMed1993

Severe flea infestation in dairy calves.

An investigation was conducted of a severe flea infestation in Holstein dairy calves. Inspection of the dairy revealed hundreds of cat fleas, Ctenocephalides felis, on 23 calves, and thousands of fleas in the barn where the calves were housed. During the investigation, > 92,000 fleas were collected from the barn. The barn also was inhabited by 30 to 35 flea-infested domesticated and feral cats. Several calves appeared emaciated, and analysis of blood samples from 10 calves revealed that 8 were anemic. A control program was initiated, consisting of insecticide and insect-growth regulator treatment of calves and premises, along with removal of straw bedding from the barn. In addition, domesticated cats were to be treated and feral cats were to be removed by live trapping. Nine weeks after a complete control program was initiated, fleas were not evident on calves or in the barn.

Anemia, Hypochromic↗

PubMed1993

Identification of a nasal nematode (Eucoleus boehmi) in greyhounds.

Eggs of Eucoleus boehmi were recovered from the faeces of greyhounds from three breeding farms and four racetrack kennels and from those of four greyhounds submitted for necropsy. Diagnosis was dependent on differentiation of the eggs of E. boehmi, E. aerophilus and Trichuris vulpis. Quantitative fecal examinations conducted weekly for 24 weeks in one greyhound suggested that the egg shedding pattern of E. boehmi is cyclical. Nasal swabs failed to reveal eggs of E. boehmi, but nasal washings gave positive results. Because of its small size (15-40 mm) its location within the epithelial lining of the nasal mucosa, turbinates, and sinuses, and difficulty in differentiating the bipolar plugged eggs, E. boehmi probably occurs more often than is currently diagnosed.

Animals↗

PubMed1993

Development of a trap for collecting newly emerged Ctenocephalides felis (Siphonaptera: Pulicidae) in homes.

The visible light spectra most attractive to cat fleas, Ctenocephalides felis (Bouché), were determined. A green-yellow filter with a transmittance spectrum centered at 515-nm and a 82.5-nm half-height width attracted significantly more fleas than any other filter or white light. This information and observations on this flea's behavior were used to design a trap with a green-yellow filter and a light source with a 10-min:5-s (on and off) cycle. This trap collected > 86% of the live fleas released into a carpeted room (3.1 by 3.3 m) during a 20-h test period, whereas each of three commercially available flea traps collected approximately 13% of the fleas. Fleas < 1 d after emergence were not as responsive to the traps as older fleas. During 20-h testing periods, this new trap caught > 57% of the fleas released 8.4 m from the trap.

Animals↗

PubMed1992

Differential activity of cythioate against female and male Ctenocephalides felis on cats.

A study was conducted to determine whether cythioate, a systemically active insecticide, has different activity against male and female Ctenocephalides felis, the cat flea. Eighteen cats were allotted equally to 1 control and 2 treatment groups and infested on day 0 with fixed ratios of male and female cat fleas. Cats in the untreated control group and treatment group 2 were infested with 50 fleas with a female-to-male ratio of approximately 2:1. Cats in treatment group 1 were infested with 50 fleas with a female-to-male ratio of 1:1. Cythioate was administered orally to cats in the treatment groups at the dosage of 3.6 mg/kg of body weight once daily on days 0 and 3. Fleas remaining after treatment were removed, sexed, and counted on day 5. The efficacy of cythioate after 2 dosings was 82.8 and 33.4% against female and male fleas, respectively. The greater activity against female fleas resulted in post-treatment female-to-male ratios in treatment groups 1 and 2 of 0.32:1 and 0.54:1, respectively. Fleas recovered from untreated control cats had a final female-to-male ratio of 2.27:1. Total population control efficacies for treatment groups 1 and 2 were 61.7 and 67.6%, respectively.

Analysis of Variance↗

PubMed1991

Blood consumption by the cat flea, Ctenocephalides felis (Siphonaptera: Pulicidae).

The volume of blood consumed by actively reproducing female cat fleas, Ctenocephalides felis (Bouché), while feeding in confinement feeding chambers on cats for 3 h, was investigated using two radionuclide blood tags (51Cr-erythrocyte and 125I-albumin) and the gravimetric method. Female fleas consumed an average of 0.110 ml (+/- 0.026 ml) of blood per 100 females in 3 h as determined using the dual radionuclide system. The single 51Cr-erythrocyte tag overestimated blood consumption by 11.3% and the single 125I-albumin tag underestimated blood consumption by 6.4%. The gravimetric method underestimated blood consumption by 72.2% compared with the dual radionuclide value. Investigations of blood consumption of nonconfined female fleas were conducted with cats housed in metabolic cages and restricted from grooming. These investigations were conducted using the single 51Cr-erythrocyte tag, and the data obtained were corrected to compensate for using a single erythrocyte tag. Female cat fleas consumed an average of 13.6 microliters (+/- 2.7 microliters) of blood per day, which was equivalent to 15.15 times their body weight. In an additional study, direct exposure to 40 kHz ultrasound did not reduce blood consumption by the fleas.

Animals↗

PubMed1989

Effects of ultrasonic flea collars on Ctenocephalides felis on cats.

Ultrasonic flea collars marketed by 2 companies were evaluated for their ability to reduce flea numbers on cats with experimentally induced flea (Ctenocephalides felis) infestations. The sound output of the collars was evaluated both before and after use to ensure that the collars were functional. Each brand was evaluated on 5 cats for a 7-day period. Collars generated peak frequencies of 40 kHz and 80 to 92 dB sound pressure level at 10 cm. An average of 98.6 and 97.4% of the fleas were still on the cats after treatment and control periods, respectively. The ultrasonic flea collars were ineffective in reducing flea numbers on these cats.

Animals↗

PubMed1989

Host association, on-host longevity and egg production of Ctenocephalides felis felis.

Host association, on-host longevity and egg production of Ctenocephalides felis felis (Bouché) were evaluated using fleas from a commercial laboratory colony and first generation, laboratory-reared, native Indiana fleas. Fleas were placed on cats that were declawed, fitted with Elizabethan collars and housed in specially designed metabolic cages. An average of 85% of the female and 58% of the male fleas stayed continuously on the cats for at least 50 days, indicating that the cat flea is a permanent ectoparasite. The maximum longevity of the cat flea was not determined, but it was shown that it can survive and reproduce on the cat for at least 113 days. A female cat flea may produce up to 1745 eggs during a 50-day period.

Animals↗