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PubMed1994

Interhost movement of adult cat fleas (Siphonaptera: Pulicidae).

Adult cat fleas, Ctenocephalides felis (Bouché), marked with orange-red or green fluorescent dye were released on one cat to study movement to another cat over a 7-d period. When the cats were separated, 3-8% of the marked fleas moved to the other cat. When the cats were allowed to remain together, 2-15% of the fleas moved. The percentage of fleas unaccounted for ranged from 8-47%. When both cats lived together, 8-15% movement occurred no matter which cat was infested. The percentage of female and male fleas unaccounted for was 8-32 and 30-47%, respectively, highlighting the importance of host grooming. Significantly fewer female cat fleas moved from one host to another than did males. The likelihood of establishing new infestations by adult fleas transferring from one host to another exists. However, visitations to environments capable of supporting immature stages of fleas seem a more important source of flea infestations.

Animals↗
PubMed1993

Allergenicity of the cat flea (Ctenocephalides felis felis)

Adult fleas, spent and unspent culture media were extracted and the radio-allergosorbent test (RAST) performed with sera of 48 cat flea skin test-positive individuals from the Tampa Bay area of Florida. Sixteen sera (33.6%) had a positive RAST to the cat flea extract prepared in our laboratory [1.7-11.4% of the total counts (TC) added]. Six of the 16 sera (12.5%) also contained specific IgE to allergens in the spent medium (0.8-3.3% TC). The allergen composition and strength were studied by RAST inhibition of two commercial cat flea extracts and compared with our in-house flea extract. The results demonstrated similar allergen compositions and different potencies. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of the in-house flea extract showed several Coomassie blue-stained bands (10-85 kD). SDS-PAGE immunoblots revealed five IgE-binding bands at 34, 35, 39, 54 and 60 kD. Flea allergens were quantified in eight house dust samples using RAST inhibition assays and expressed as RAST inhibition units; five of these samples contained detectable levels. Cat flea allergens may contribute to the allergenicity of house dust in areas of heavy flea infestation.

Allergens↗
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↗
PubMed2003

Detection of R. felis and R. typhi in fleas using monoclonal antibodies.

Rickettsia typhi and R. felis are flea-transmitted human pathogenic rickettsial species. To investigate the distributional dynamics of these rickettsiae we designed a micro-immunofluorescence assay (MIF) using species-specific monoclonal antibodies (MAbs) applied to flea cryosections. Our assay was performed in less than 3 h and its applicability was demonstrated by the detection of R. typhi in 50 artificially infected human body lice but in none of 50 uninfected lice. With MIF, we identified 31 positive among 32 fleas proven with PCR to be naturally infected with R. felis; and 7 positive among 32 fleas proven with PCR to be naturally infected with R. typhi. No cross-detection was observed with both MAbs. Fresh R. felis-infected fleas were significantly more MIF-positive than long conserved R. typhi-infected fleas (31/32 vs. 7/32, P < 0.01). This discrepancy may be linked to degradation of antigens by long-term freezing. For R. typhi-infected fleas, our assay was significantly more efficient when applied to fleas in early stages of infection (less than 15 days) by comparison with fleas frozen more than 20 days after infection (7/15 vs. 0/17, P = 0.01). This difference may be related to an antigenic modification caused by selection pressure in the vector and host process. The sensitivity of the described method did not exceed 47% (7/15) for R. typhi but, in contrast, was 97% for R. felis. Thus, our method appears to be useful for surveillance in R. felis infections, but requires further studies for the detection of R. typhi.

Animals↗
PubMed2002

Factors influencing sperm transfer and insemination in cat fleas (Siphonaptera: Pulicidae) fed on an artificial membrane system.

Sperm transfer through the epididymis, a prerequisite for insemination of cat fleas, Ctenocephalides felis (Bouché) was stimulated by exposure of unfed male fleas to juvenile hormone III residues for 3 d at 25 degrees C or exposure of unfed fleas to 37 degrees C for 6 d. Sperm transfer was completed at least three times faster in unfed males held at 37 degrees C than in those held at 25 degrees C. Although percentage sperm transfer in fleas fed water or 0.15 M saline at 37 degrees C was not significantly increased over that of unfed fleas, a significantly greater percentage of blood-fed males completed sperm transfer at 2, 3, and 6 d. At least two factors influenced insemination: exposure of fleas to host body temperature and amount of food consumption. When blood-fed males and females were paired and fed 0.15 M saline, 0% were inseminated at 25 degrees C versus 35% at 37 degrees C. Because percentage insemination did not increase in blood-fed males and females that were paired and fed 0.15 M saline at 37 degrees C for an additional 48 h, continuous bloodfeeding appeared to be required for maximal rates of mating and insemination. Furthermore, no females were inseminated when blood-fed males and females were paired at 37 degrees C and starved. Treatment of unfed fleas with juvenile hormone III did not substitute for bloodfeeding in stimulating mating and insemination; when blood-fed males were paired with JH III-treated females and vice versa and fed 0.15 M saline at 37 degrees C, 0% were inseminated. However, when fleas were fed 0.15 M saline and exposed to 1,250 ppm juvenile hormone III or fed whole blood and exposed to 12.5, 125, or 1,250 ppm juvenile hormone III, percent insemination was significantly increased in comparison to the controls. Therefore, juvenile hormone secretion in blood-fed fleas may regulate mating success indirectly by stimulating sperm transfer.

Animals↗
PubMed2002

Studies on the growth of Bartonella henselae in the cat flea (Siphonaptera: Pulicidae).

Two out of three pools of cat fleas, Ctenocephalides felis (Bouche), that were fed Bartonella henselae-positive cat blood for 3 d and then bovine blood for 3 d, were polymerase chain reaction (PCR) positive for B. henselae. In a second experiment, three cats were inoculated with a streptomycin-resistant strain of B. henselae. After the cats were inoculated, caged cat fleas were fed on the cats during three different periods, and then pooled and transferred to noninfected recipient cats. In the first trial, the bacteria in the flea feces were below level of detection when the fleas were transferred from the infected cats to the recipient cat. After the fleas had fed on the recipient cat for 6 d, a bacteria level of 4.00 x 10(3) CFU/ mg was detected in the flea feces. Subsequently, the bacteria level increased for 4 d and then declined. In another experiment, the bacteria level in the flea feces was 1.80 x 10(3) CFU/mg at 2 h after collection and 3.33 x 10(2) CFU/mg at 72 h after collection. These data indicated that this strain of B. henselae can persist in flea feces in the environment for at least 3 d, and that B. henselae can multiply in the cat flea.

Animals↗
PubMed2005

Prevalence of human pathogens in cat and dog fleas in New Zealand.

AIMS: To provide further information on the prevalence of Rickettsia felis, Bartonella hensela, and B. clarridgeiae in cat and dog fleas in New Zealand and their distribution in the country. METHODS: We used PCR and sequencing with primers for the its and pap 31 (for Bartonella spp.), and the gltA and OmpB (for Rickettsia spp.) genes on DNA from fleas collected from dogs and cats presenting to 3 widely separated veterinary practices on the North Island. RESULTS: DNA of R. felis (19%), B. henselae (11%), and B. clarridgeiae (7%) was found in the 114 cat fleas (Ctenocephalides felis) we studied. The DNA of both B. henselae and B. clarridgeiae was found in 3 fleas (from 2 animals); B. clarridgeiae and R. felis in 1 flea; B. henselae and R. felis in 5 fleas (from 3 animals); and R. felis, B. henselae, and B. clarridgeiae in 2 fleas (from 1 animal). No amplicons were obtained from 3 dog fleas (Ctenocephalides canis). CONCLUSIONS: The emerging human pathogens, R. felis, B. henselae, and B. clarridgeiae, are prevalent and widely distributed in cat fleas in the North Island of New Zealand.

Animals↗
PubMed1996

Impact of an orally administered insect growth regulator (lufenuron) on flea infestations of dogs in a controlled simulated home environment.

OBJECTIVE: To evaluate the ability of lufenuron to control cat flea (Ctenocephalides felis felis) populations on dogs under conditions simulating a naturally infested home environment. DESIGN: 2 treatment and 2 control groups of dogs. Treated dogs received lufenuron in tablet form monthly, and controls received excipient. Dogs had unrestricted access to indoor (carpeted) and outdoor (grassy) environments in which self-propagating flea populations had been established. ANIMALS: 17 adult female Beagles. PROCEDURE: Dogs were monitored for 77 days after initial infestation with fleas and 70 days after initial treatment. Efficacy of the drug was calculated on the basis of absolute reduction in flea counts and as a percentage of control. RESULTS: Lufenuron administration caused a statistically significant (P < 0.05) reduction in flea burdens in treated dogs, compared with controls. Initiation of treatment 7 days after infestation resulted in 75% control of F1-generation and 97% control of F2-generation fleas over a 70-day posttreatment period. CONCLUSIONS: Lufenuron was highly effective in reducing flea populations on dogs. The time required for control will vary with the duration (generation time) of the flea reproductive cycle and, hence, the geographic area in which the product will be used. The experimental results are most relevant to use of the product for control of an existing flea population in the Midwest.

Administration, Oral↗
PubMed2006

Locomotor response to light and surface angle in three species of desert fleas.

We studied the relocation of newly emerged and fed individuals of three species of desert fleas (Xenopsylla conformis, Xenopsylla ramesis, and Parapulex chephrenis) in response to light and surface angle. We observed flea movements inside of either horizontal or tilted cardboard tubes with different light regime at their ends. Proportion of relocating X. conformis and X. ramesis was significantly higher than that of P. chephrenis. In this species only, adult individuals relocated more frequently than newly emerged individuals, and females relocated more frequently than males. In general, the majority of fleas moved toward light independently of its position in relation to the surface angle. Fleas moved toward light even if it was positioned at the lower end of a tube. When both ends of a tube were darkened, newly emerged Xenopsylla moved randomly toward the upper or lower end of a tube, whereas newly emerged P. chephrenis moved mainly toward the upper end of a tube. Adult P. chephrenis and X. conformis also moved mainly toward the upper end of a tube, whereas adult X. ramesis moved mainly toward the lower end. When both ends of a tube were lighted up, newly emerged females of all species, as well as newly emerged female X. ramesis, randomly relocated toward the upper or lower end of a tube. In contrast, newly emerged males and adults of both sexes of P. chephrenis and X. conformis as well as adult female X. ramesis moved mainly toward the upper end of a tube, whereas adult male X. ramesis moved mainly down. Results of this study suggest that light is a more important abiotic signal for flea orientation than surface angle, and there are species-specific differences in flea responses to light and angle stimuli. These differences are related to spatial ecology and behavior of fleas' main hosts as well as to fleas' environmental preferences.

Age Factors↗
PubMed1994

IgG and IgE antibodies against antigens of the cat flea, Ctenocephalides felis felis, in sera of allergic and non-allergic dogs.

Antigens from a soluble extract of cat fleas (FS) were separated using SDS-PAGE, and transferred to nitrocellulose paper. Sera from dogs shown by use of a provocative flea feeding test to be either allergic (23 dogs) or non-allergic (20 dogs) to flea bites, were used in Western blots to identify flea antigens that react with canine IgG or IgE. The sera were also tested in ELISA against FS to quantify levels of IgG and IgE antibodies. Antibodies present in the sera of both flea allergic and non-allergic dogs identified multiple antigens. There was a great diversity of responses within each group, and there was no pattern of reactivity that distinguished dogs with flea allergy from dogs not allergic to fleas. IgG and IgE antibodies were not significantly different between the two groups of dogs. These results demonstrated that there is little association between particular antibody responses and allergic reactivity of dogs to fleas.

Allergens↗
PubMed1995

Effect of combing time on cat flea (Ctenocephalides felis) recovery from dogs.

Combing the haircoat to count fleas has been used to determine the efficacy of insecticides against fleas on dogs, but no standardization of method has been reported. In this study, the effect of combing time on flea recovery from dogs was examined. Six beagle dogs were infested with 100 unfed, adult Ctenocephalides felis (Bouché) on each of three consecutive days. A crossover design, balanced for carryover effects, was used to evaluate flea removal rates from each dog by comb-counting for three different time intervals; i.e. 5, 10 and 15 min. Each dog was combed once at each time interval on a different day, over three consecutive days. The results showed that the majority of fleas were recovered in the first 5 min of combing and there were no significant differences (P > or = 0.19) in the total number of fleas recovered between the 5, 10 or 15 min protocols. Moreover, the standard deviation and coefficient of variation increased with an increase in the amount of time spent combing, resulting in a decrease in precision for the longer protocols. Therefore, the comb time of 5 min provided a precise and accurate representation of the number of fleas present on an animal and could be useful as a standard measure of flea infestation levels in efficacy trials.

Animal Husbandry↗
PubMed2006

A plant-based repellent protects against Tunga penetrans infestation and sand flea disease.

Tungiasis is a parasitic skin disease prevalent in impoverished populations in the tropics and associated with considerable morbidity. Treatment options are limited and prophylaxis has never been attempted. We assessed the effectiveness of a plant-based repellent to prevent infestation with Tunga penetrans and sand flea disease in an urban squatter settlement in Fortaleza, Northeast Brazil. Two cohorts were formed. One cohort started with the intervention while another served as control. The plant-based repellent Zanzarin was applied twice daily on the skin of the feet. After 4 weeks and a wash-out-phase of another 2 weeks, cross-over was performed. Study members were examined twice per week for the presence of newly embedded sand fleas. The number of viable and dead sand fleas and the total number of sand flea lesions were determined. Sentinel rats were used to assess local transmission dynamics. Outcome measures were the number of newly embedded sand fleas per individual per day, number of sand flea lesions per individual according to the stage, as well as type and degree of clinical pathology. Zanzarin applied twice daily on the feet reduced the number of newly embedded fleas by 92% (interquartile range 81-100%), the total number of lesions by 87% (81-98%) and reversed tungiasis-associated clinical pathology almost completely. In conclusion, in a setting in which tungiasis is an important health threat, the daily application of a plant-based repellent prevented the infestation with T. penetrans and sand flea disease.

Administration, Topical↗
PubMed2000

Dose selection of selamectin for efficacy against adult fleas (Ctenocephalides felis felis) on dogs and cats.

Selamectin, a novel avermectin, was evaluated in two controlled studies (one in Beagles, one in domestic shorthaired cats) to determine an appropriate topical dose for efficacy against adult Ctenocephalides felis felis (C. felis) fleas on dogs and cats for 1 month. For each study, animals were allocated randomly to four treatments. One treatment consisted of the inert formulation ingredients (vehicle) administered as a negative control, and the other three treatments consisted of a single topical dosage of 3, 6, or 9mgkg(-1) of selamectin. In each study, selamectin was administered as a topical dose applied to the skin in a single spot at the base of the neck in front of the scapulae. Dogs and cats were infested with 100 viable unfed C. felis (50 males and 50 females) on days 4, 11, 18, and 27. Seventy-two hours (+/-2h) after each infestation, on days 7, 14, 21, and 30, a comb count to determine the number of viable fleas present on each animal was performed. Efficacy of selamectin on day 30 was used to select an appropriate dose. For dogs and cats, percentage reductions in geometric mean flea comb counts for the three selamectin treatments ranged from 94. 6 to 100% on days 7, 14, and 21, compared with the negative-control treatment. On day 30, reductions in flea comb counts were 81.5, 94.7, and 90.8% for dogs, and 79.8, 98.0, and 96.2% for cats treated with selamectin at 3, 6, or 9mgkg(-1), respectively. For day 30 flea comb counts for dogs and cats, analysis of variance showed that the three selamectin treatments resulted in significantly (P< or =0.05) lower counts than did the negative-control treatment. For dogs and cats, geometric mean flea counts for selamectin administered at a dosage of 3mgkg(-1) were significantly (P< or =0.05) higher than those for the 6 and 9mgkg(-1) treatment dosages combined. There were no significant differences in flea counts between the 6 and 9mgkg(-1) treatments. This analysis was confirmed by linear-plateau modeling. Thus, the optimal dose of selamectin for efficacy against adult fleas for both dogs and cats, as estimated by the turning point (plateau) in the dose response curve, was 6mgkg(-1).

Administration, Topical↗
PubMed1975

The differential transmissibility of Myxoma virus strains of differing virulence grades by the rabbit flea Spilopsyllus cuniculi (Dale).

Laboratory studies showed that few rabbit fleas (Spilopsyllus cuniculi (Dale)) transmitted myxomatosis after removal from wild rabbits (Oryctolagus cuniculus (L) that had been infected for fever than 10-12 days, irrespective of the virulence of the myxoma virus strain involved. Rabbits infected with fully virulent (Grade I) strains died within 10-15 days and few fleas from these hosts became infective; averaging all the samples takem. 12% of the fleas were infective. Also, few fleas acquired infectivity on individual rabbits which covered from infection with attenuated strains; the mean was 8% infective. Rabbits which died between 17 and 44 days after infection had higher proportions of infective fleas at all sampling times; the mean was 42% infective. Male and female fleas transmitted virus with equal efficiency. For rabbits infected with any of the attenuated virus strains the mean percentage of infective fleas was inversely related to the survival time of the host. Rabbits infected with moderately attenuated strains (Grades IIIA and IIIB) had, on average, the highest proportion of infective fleas; hence such strains have a selective advantage and have become predominant under natural conditions in Britain. The changes that might occur if there is an increase in host resistance to myxomatosis are discussed.

Animals↗
PubMed1975

Seasonal variation in numbers of the rabbit flea on the wild rabbit.

Samples of rabbits were obtained throughout each month over the 4-year period 1967-70. All fleas were removed, sexed and counted and the reproductive condition of the rabbits recorded. Rabbit fleas Spilopsyllus cuniculi (Dale) were present on both sexes of rabbit at all times of the year. In each year significantly high numbers of fleas were found on the rabbits in January, February, March and April and significantly low numbers in August, September and October. Mean flea counts were significantly higher on female rabbits than on males during April, May and June. During the rest of the year counts from each sex of host did not differ significantly. There were significant differences in flea numbers between years. More female than male fleas were found on both sexes of host throughout the year. The rabbit population sampled is shown to be typical of post-myxomatosis populations with regard to breeding performance and juvenile mortality. The relationship of the observed patterns of change in flea numbers to host and flea breeding and to host behavior, population size and structure is discussed.

Animals↗
PubMed2001

Induction of feline flea allergy dermatitis and the incidence and histopathological characteristics of concurrent indolent lip ulcers.

The objectives of this study were to characterize the role of intermittent vs. continual flea exposure in the development of flea allergy dermatitis (FAD) in cats, assess the accuracy of intradermal skin testing (IDST) and in vitro testing, and document the incidence and histopathological features of indolent lip ulcers. Ten flea-naive cats were divided into two groups. One group received intermittent flea exposure for 120 days. Thereafter, both groups of cats received continuous flea exposure for 120 days. In vitro testing for flea salivary antibody and IDST utilizing both whole flea antigen and flea salivary antigen were performed. Eight of 10 cats developed clinical signs of FAD within 3 months and five of these eight cats developed lip ulcers which where characterized histopathologically by ulceration with predominantly neutrophilic inflammation and surface bacterial colonization. There was no association between the presence or absence of clinical signs and positive IDST or in vitro results, and no difference in the development of clinical signs was noted between the two groups of cats.

Animals↗
PubMed2006

Early-phase transmission of Yersinia pestis by unblocked fleas as a mechanism explaining rapidly spreading plague epizootics.

Plague is a highly virulent disease believed to have killed millions during three historic human pandemics. Worldwide, it remains a threat to humans and is a potential agent of bioterrorism. Dissemination of Yersinia pestis, the etiological agent of plague, by blocked fleas has been the accepted paradigm for flea-borne transmission. However, this mechanism, which requires a lengthy extrinsic incubation period before a short infectious window often followed by death of the flea, cannot sufficiently explain the rapid rate of spread that typifies plague epidemics and epizootics. Inconsistencies between the expected rate of spread by blocked rat fleas and that observed during the Black Death has even caused speculation that plague was not the cause of this medieval pandemic. We used the primary vector to humans in North America, Oropsylla montana, which rarely becomes blocked, as a model for studying alternative flea-borne transmission mechanisms. Our data revealed that, in contrast to the classical blocked flea model, O. montana is immediately infectious, transmits efficiently for at least 4 d postinfection (early phase) and may remain infectious for a long time because the fleas do not suffer block-induced mortality. These factors match the criteria required to drive plague epizootics as defined by recently published mathematical models. The scenario of efficient early-phase transmission by unblocked fleas described in our study calls for a paradigm shift in concepts of how Y. pestis is transmitted during rapidly spreading epizootics and epidemics, including, perhaps, the Black Death.

Animals↗
PubMed1992

Spectrophotometric method of quantifying adult cat flea (Siphonaptera: Pulicidae) feces.

Cat flea, Ctenocephalides felis felis (Bouché), feces are an essential part of larval nutrition under natural conditions. The mass values of adult flea feces can be measured by dissolving samples of flea feces in Drabkin's reagent, filtering, centrifuging, and measuring absorbance spectrophotometrically at 540 nm. Either flea feces or air-dried host blood can be used to generate the standard curve used to convert absorbance (optical density) values into mass values. Debris collected from flea-infested house cats averaged 23.02 mg debris per cat per h with an average of 10.41 mg flea feces per cat per h. Flea feces deposited in the environment serve as potential larval food. Adult flea feces comprised an average of 44.28% of the debris deposited from infested domestic house cats in this study.

Animals↗