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PubMedDate not supplied

[Experimental study of the infecting ability of the flea Coptopsylla lamellifer rostrata in the Kyzylkum natural focus of plague].

Experimental infecting of the fleas Coptopsylla lamellifer rostrata by plague was carried out. The fleas were infected by feeding through biomembrane (skin of a white mouse) with a mixture of defibrinated blood of guinea-pig and plague microbes. Under concentration 2-3 milliard of the microbes in 1 millilitre, from 60 to 100% of the fleas were infected. Forming of the block of proventriculus was observed in 9-13 day. Mean percent of blocking for all experiments was less than 1%. Maximal rate of blocking (2.8%) was observed in the experiment under everyday 3-hour feeding. After planting of the fleas with blocks on great gerbil (2 fleas on one gerbil) 20% of the gerbils were infected. The conclusion had been made that C. lamellifer rostrata has only insignificant effectiveness as a vector of plague agent in Kyzylkum. Probably it is caused by some specific features of this subspecies.

Animals↗
PubMed2005

The evolution of flea-borne transmission in Yersinia pestis.

Transmission by fleabite is a recent evolutionary adaptation that distinguishes Yersinia pestis, the agent of plague, from Yersinia pseudotuberculosis and all other enteric bacteria. The very close genetic relationship between Y. pestis and Y. pseudotuberculosis indicates that just a few discrete genetic changes were sufficient to give rise to flea-borne transmission. Y. pestis exhibits a distinct infection phenotype in its flea vector, and a transmissible infection depends on genes that are specifically required in the flea, but not the mammal. Transmission factors identified to date suggest that the rapid evolutionary transition of Y. pestis to flea-borne transmission within the last 1,500 to 20,000 years involved at least three steps: acquisition of the two Y. pestis-specific plasmids by horizontal gene transfer; and recruitment of endogenous chromosomal genes for new functions. Perhaps reflective of the recent adaptation, transmission of Y. pestis by fleas is inefficient, and this likely imposed selective pressure favoring the evolution of increased virulence in this pathogen.

Animals↗
PubMed2006

Surveillance of Egyptian fleas for agents of public health significance: Anaplasma, Bartonella, Coxiella, Ehrlichia, Rickettsia, and Yersinia pestis.

Serologic surveys in Egypt have documented human and animal exposure to vector-borne bacterial pathogens, but the presence and distribution of these agents in arthropods has not been determined. Between July 2002 and July 2003, fleas were collected from 221 mammals trapped in 17 cities throughout Egypt. A total of 987 fleas were collected, representing four species (Ctenocephalides felis, Echidnophaga gallinacea, Leptopsylla segnis, and Xenopsylla cheopis); 899 of these fleas were X. cheopis from rats (Rattus spp.). Fleas were tested for DNA from Anaplasma spp., Bartonella spp., Coxiella burnetii, Ehrlichia spp., Rickettsia spp., and Yersinia pestis. Rickettsia typhi, the agent of murine typhus, was detected in X. cheopis and L. segnis from rats from nine cities. A spotted-fever group Rickettsia sp. similar to "RF2125" was detected in E. gallinacea, and two unidentified spotted fever group Rickettsia were detected in two X. cheopis. Novel Bartonella genotypes were detected in X. cheopis and L. segnis from three cities. Coxiella burnetii was detected in two fleas. Anaplasma, Ehrlichia, and Y. pestis were not detected.

Animals↗
PubMedDate not supplied

[The formation of proventriculus block, alimentary activity and mortality of flea Amphipsylla primaris primaris infected with Yersinia pestis].

The results of experiments held in 1982-1983 in Tuva plague natural focus with flea Amphipsylla primaris primaris (Jordan et Rothschild, 1915) from natural populations, whish were inflected and fed on specific host--flat-headed vole (Alticola strelzovi), are analyzed. The initial infectivity of the insects in autumn was higher than in spring: 90 and 50 % respectively. Accumulation of the agent in aggregated form in the organism of A. p. primaris, estimated by the quantity of fleas with < > and partial blocks, was more active in imago of both sexes in autumn than in spring, while sucking flea were observed in spring more often than in autumn. Irrespective of season, the part of males with visible accumulations of Y. pestis was more, and their alimentary activity was higher than that of females. Fleas died much more quickly in spring. Part of the males with proventriculus block exceeded that of females in spring experiment. Females with alimentary canal obstruction prevailed in autumn. Thus, sex of the insect and season of the experiment conducting influenced on all studied indices. Besides that, Y pestis ability for the proventriculus block formation in fleas during different seasons can change by the opposite way depending on sex of the ectoparasites.

Animals↗
PubMed1986

Flea control on pets in southern Africa.

Aspects of the biology and life-cycle of the flea which are important to the practising veterinarian are discussed. The "cat flea", Ctenocephalides files is the most prevalent species on dogs and cats in those parts of the world where it has been surveyed. Whether the flea is a temporary or permanent obligatory parasite is still a controversy. The insecticides and product formulations available for flea control in South Africa are reviewed with emphasis on the systematic agent, fenthion. Practical protocols for flea control on dogs and cats are proposed.

Animals↗
PubMed1979

Investigation on the transfer of fleas among small mammals using radioactive phosphorus.

The transfer of fleas Megabothris turbidus, Ctenophthalmus agyrtes, Nosopsyllus fasciatus etc. was investigated by labelling the bank vole (Clethrionomys glareolus Schreb.) with radioactive phosphorus. On the one hand, the process of flea transfer was traced among different individuals of the same host species, and on the other, among different host species (C. glareolus, Apodemus flavicollis Melch.). The investigations revealed that the flea transfer in a rodent nest visited by another host depended partly on the number of fleas present in the nest, partly on the period spent by the new-comer in it. Conversely, the number of fleas transferred in the nest by the newly arrived host depended on the temperature of nest bedding and on the initial nest occupation by other host.

Animals↗
PubMedDate not supplied

[Experimental study of the participation of gamasid mites and fleas in circulating the tick-borne encephalitis virus (a review)].

The paper presents analysis of literary data on experimental infection of 11 species of gamasid mites and 10 species of fleas with tick-borne encephalitis virus (TE) and experiments on transmission of the virus to animals by 9 species of gamasids and 14 species of fleas. Nearly all investigated species can perceive the virus, preserve it from some hours to two months and transmit it to animals within a period of 24 hours to two months after experimental infection. The fact of transmission of the virus to animals was established by the presence of recipients in the brain or by the presence of antibodies. To settle the question of the possible participation of gamasids and fleas in the circulation of the virus TE in nature threshold doses of the virus for infection of mites and fleas of different species, mechanism of transmission of the virus to animals by gamasid mites, facultative haematophags , titers and terms of virusemia in animals which obtained the virus from gamasid mites or fleas should be established.

Animals↗
PubMedDate not supplied

[Main traits of the annual cycles of the fleas (Aphaniptera) of the mountain suslik in the Baksan River valley].

Data are given on the fleas of Citellus musicus from Central Caucasus. Ecological peculiarities of fleas from the above region were compared with data known for fleas from plain Precaucasus. Differences between annual cycles of fleas of the same species from two altitude belts of the Baksan valley are considered. Epizootological significance of ecological peculiarities of fleas in the Baksan plague nidus is discussed.

Animals↗
PubMedDate not supplied

[The duration of the persistence of the plaque microbe in the body of the flea Citellophilus tesquorum altaicus].

Experiments have established that the plague bacillus persists long in the flea C. tesquorum altaicus in the Tuva natural foci. Experimentally, 64.2 to 77.3% of the fleas inoculated in autumn survived winter. More than one-half preserved the plague bacillus. From 0.7 to 19.4% of the inoculated fleas survived from one summer to another. The plague persisted in 30% of the insects. Individual C. tesquorum altaicus females survived two winters, preserving the bacillus for 21.5-22.0 months. The fact that the fleas has survived both one and two winter periods in coma transmitted the plague bacillus to healthy sousliks has been recorded. Rather late periods (278-411 days) of blocking the fleas after the insects' inoculating feeding have been defined.

Animals↗
PubMed1976

Ultrastructural comparison of the midgut epithelia of fleas with different feeding behavior patterns (Xenopsylla cheopis, Echidnophaga gallinacea, Tunga penetrans, Siphonaptera, Pulicidae).

This morphological study describes the ultrastructure of the midgut of three flea species, including temporary parasitic fleas (both sexes of Xenopsylla cheopis, males and immature females of Echidnophaga gallinacea and Tunga penetrans) and stationary parasitic fleas (mature females of E. gallinacea and T. penetrans). (1) Three cell types (a,b,c) constitute the midgut epithelium, each appearing in a characteristic and constant frequency along the whole midgut, a) The functional digestive cells form the main part of the epithelium as one layer of cylindric cells. Nuclear volume and nucleus/cytoplasm ratio have been estimated (with morphometric methods) to be the same in both sexes of E. gallinacea and T. penetrans. b) Some single regenerative cells or nests, containing 5-10 cells per section plane, lay at the base of the epithelium (2-3 cells or nests per cross section of a midgut). c) Secretory cells are characterized by their opaque cytoplasm which contains electron-dense vesicles. They have few microvilli and no basal labyrinth and are placed between digestive cells only as single cells (1-2 per cross section of a midgut). (2) After the first bloodmeal some ultrastructural changes occur in the midgut of all fleas. These changes are interpreted as a structural reflection of metabolic processes such as secretion of digestive enzymes, resorption, storage and transport of digested nutrients, and synthesis of digestive enzymes. (3) More conspicious changes occur in the midgut of the stationary parasitic and maturing females of E. gallinacea and T. penetrans. The nuclear volumes of the digestive cells reach the two-fold and eight-fold value, respectively. The nucleus/cytoplasm ratio decreases by half. The corresponding cytoplasmic growth of each cell is reflected in an enlargement of the whole midgut. The digestive cells form long apical cell extensions. The nucleus, basal labyrinth, rer, and golgi complex all change their morphology, and this can be interpreted as the result of a higher level of metabolic activity than during the first bloodmeal. (4) The midgut of the oviparous female of T. penetrans undergoes a process of compensatory hypertrophy which consists in the cellular hypertrophy of each digestive cell and in an extensive proliferation of the regenerative cells. A unique structure, called 'nuclear halo' appears within the process of cellular hypertrophy. This structure consists of a layer of 70-100 A thick filaments along the periphery of the nucleus. The nuclear halo contains few ribosomes and is screened from the cytoplasm by an rer cisterna. The filaments may contain RNA molecules which are on their way to the cytoplasm. It has been demonstrated that the structure of the midgut epithelium is influenced by the nutritive and parasitic behavior of the flea. The stationary and oviparous E. gallinacea and T. penetrans reveal an extensive and irreversible change of their midgut epithelium.

Animals↗
PubMed1997

Fleas and lice parasitizing mammals in Missouri.

Three species of chewing lice, 11 species of sucking lice, and 28 species of fleas are recorded from mammals in Missouri. Of these, seven species of sucking lice (Hoplopleura acanthopus, Hoplopleura hesperomydis, Hoplopleura sciuricola, Neohaematopinus sciuri, Neohaematopinus sciurinus, Neohaematopinus sciuropteri, and Solenopotes ferrisi) and one species of flea (Doratopsylla blarinae) represent new state records. From 1993 to 1995, 773 individual mammals were examined for ectoparasites in southeastern Missouri. One species of chewing louse, 6 species of sucking lice, and 11 species of fleas were recovered from 18 of the 21 mammal species examined. Ctenophthalmus pseudagyrtes was recovered from more mammal species (6) than any other flea species; and the white-footed mouse, Peromyscus leucopus, was parasitized by more flea species (5) than other hosts examined. Except for H. sciuricola, which was recovered from two congeneric species of tree squirrels, each species of louse was confined to a separate host species.

Animals↗
PubMed1996

Genotypic identification of murine typhus Rickettsia in rats and their fleas in an endemic area of Greece by the polymerase chain reaction and restriction fragment length polymorphism.

Forty-nine cases of murine typhus were diagnosed in recent years in residents of several communities around the city of Chalkis, the capital of the Prefecture of Evia. (Euboea) Evia is an island connected to central mainland Greece by a bridge. To investigate the endemicity of murine typhus in this area, 226 fleas (Xenopsylla cheopis) and blood samples were collected from 53 rats (Rattus norvegicus) trapped in this area. The polymerase chain reaction followed by restriction fragment length polymorphism analysis (PCR-RFLP) was used to detect and identify Rickettsia typhi, the etiologic agent murine typhus, in the rat blood samples (buffy coat cells) as well as in their fleas. An indirect immunofluorescent antibody (IFA) assay was performed to detect antibodies against R. typhi in rat serum samples. The presence of R. typhi in both fleas and rat blood samples was demonstrated. The frequency of infection for X. cheopis was 4%, while 18% of the rats had buffy coat cells infected, and 92% of the rat sera tested by IFA were positive for anti-R. typhi antibodies. The present work is the first successful application of PCR-RFLP in a field study of naturally infected rats and their fleas in Europe.

Animals↗
PubMed2006

Morbidity assessment in sand flea disease (tungiasis).

Tungiasis, caused by the sand flea Tunga penetrans, is a health problem in many impoverished communities in Latin America, the Caribbean, and sub-Saharan Africa. Sand flea disease is associated with a broad spectrum of clinical and histological pathology. The factors determining the disease burden in endemic communities are not well understood, and severity of clinical pathology has never been assessed quantitatively. Thus, two severity scores were developed: one for acute disease and one for chronic sequels. These scores were evaluated in a cohort of 70 severely infested patients living in a shantytown in Fortaleza, a capital city in Northeast Brazil. Patients were examined during a period of 25 days and followed-up after a twice daily application of a plant-based repellent to prevent reinfestation. The severity score for acute disease symptoms significantly correlated with the infestation rate and the number of embedded fleas. It turned zero when reinfestation was prevented. The score for chronic disease also significantly correlated with the infestation rate. Tungiasis is associated with considerable acute and chronic morbidity. The degree of acute morbidity is directly related to the number of embedded sand fleas. When transmission is interrupted, the chronic morbidity reflects the infestation rates individuals have experienced in the past.

Adolescent↗
PubMed2002

Density-dependent host selection in ectoparasites: an application of isodar theory to fleas parasitizing rodents.

Parasites should make the same decisions that every animal makes regarding fitness reward. They can maximize reproductive success by selection of those habitats that guarantee the greatest fitness output. We consider the host population as a habitat of a parasite population. Consequently, hosts (=habitats) that differ quantitatively or qualitatively will support different numbers of parasites. The nature of habitat selection can be detected by isodars, lines along which habitat selection yields equivalent fitness reward. We applied this approach to study host selection of five fleas, each infesting two desert rodents. Xenopsylla conformis, Xenopsylla ramesis, Nosopsyllus iranus theodori and Stenoponia tripectinata medialis parasitize Gerbillus dasyurus and Meriones crassus. Synosternus cleopatrae pyramidis parasitizes Gerbillus andersoni allenbyi and Gerbillus pyramidum. Three fleas ( X. conformis, X. ramesis and S. c. pyramidis) were able to perceive quantitative (amount of the resource; e.g. organic matter in the nest for flea larvae) and/or qualitative (pattern of resource acquisition; e.g. host defensiveness) differences between hosts. Two other fleas did not perceive between-host differences. X. conformis was a density-dependent host selector that showed sharp selectivity at low density. X. ramesis and S. c. pyramidis were density-independent host selectors with a direct correspondence of density with habitat quality. N. i. theodori and S. t. medialis were non-selectors with no relationship at all between density and host quality. The results of the application of the isodar theory suggest that ectoparasites, like other animals, behave as if they are able to make choices and decisions that favour environments in which their reproductive benefit is maximized.

Animals↗
PubMed1987

Flea species from dogs and cats in north-central Florida.

Fleas were identified after removal from 100 dogs and 60 cats following routine presentation at a Veterinary Hospital in Gainesville, FL. Ctenocephalides felis comprised 92.4% and 99.8% of the fleas taken from dogs and cats respectively. Pulex irritans accounted for 7.5% of the fleas found on dogs and for 0.2% of those found on cats. Echidnophagia gallinacia was found on one dog. Of the 100 dogs, 80 were infested with C. felis alone, one with P. irritans alone, and 18 carried a mixed infestation of the two. One animal was infested with all three species. Ctenocephalides canis was not identified amongst the total of 1887 fleas examined.

Animals↗
PubMed1990

Characterization of the salivary apyrase activity of three rodent flea species.

1. Salivary gland lysates of the adult female fleas Oropsylla bacchi, Orchopea howardi and Xenopsylla cheopis hydrolyse ATP and ADP, but not AMP, thus characterizing the existence of a salivary apyrase activity. 2. In all species Mg++ or Ca++ function as activators, and a pH optimum between 7 and 8 is observed. 3. Salivary gland lysates of male fleas contain significantly smaller amounts of the enzyme activity than do those of female fleas. 4. Immediately following a blood meal, apyrase activity and protein content of female X. cheopis salivary glands are 2-3-fold less than that of unfed fleas, indicating that salivary apyrase activity is secreted during feeding. 5. It is suggested that, as in other arthropods, salivary apyrase may facilitate blood location and blood feeding by preventing ADP-induced platelet aggregation at the site of the bite.

Animals↗
PubMedDate not supplied

Metabolic rate and jump performance in seven species of desert fleas.

We hypothesized that sexual and interspecific differences in jumping performance of fleas found in our previous study are correlated with differences in resting metabolic rate (RMR) between sexes and among species. To test this hypothesis, we measured RMR of seven flea species (Xenopsylla conformis mycerini, Xenopsylla ramesis, Xenopsylla dipodilli, Parapulex chephrenis, Synosternus cleopatrae pyramidis, Nosopsyllus iranus theodori and Stenoponia tripectinata medialis). We compared RMR between sexes and among species and examined whether there is intra- and interspecific correlation between RMR and jumping ability. Both mass-specific and mass-independent RMR were the highest in female S. t. medialis, whereas mass-specific RMR was the lowest in male X. dipodilli and mass-independent RMR was the lowest in three Xenopsylla species and P. chephrenis. Mass-specific and mass-independent RMR were significantly higher in females than in males in all fleas except S. t. medialis. Differences in jumping ability between males and females were found to be correlated with sexual differences in mass-specific or mass-independent RMR. Interspecific comparison showed that the length of jump in both male and female fleas was strongly affected by their mass-specific and mass-independent RMR.

Animals↗
PubMed2006

Qualitative and quantitative observations on the flea population dynamics of dogs and cats in several areas of Germany.

From an ongoing country-wide study on the spectrum, the epidemiology and the population dynamics of flea infestations in dogs and cats, important preliminary results from the three areas of Karlsruhe, Nuernberg and Leipzig are presented. A total of 1922 dogs and 1838 cats from 12 different veterinary practices or clinics in three areas of Germany were systematically examined between July 2003 and June 2004. All dogs and cats appearing for a clinical veterinary consultation on one regular working day per month, per practice, were clinically examined. Dogs and cats were examined irrespective of any kind of prior therapeutic or prophylactic insecticidal treatment. The results show that a total of 99 dogs (5.13%) and 263 cats (14.33%) were infested. Cats were more often flea-infested than dogs (p < 0.05). The highest infestation rates for dogs (x = 7.87%) were detected between July and October, and for cats (x = 21.14%) between July and September, the lowest infestation rates for dogs (x = 2.88%) were observed between November and May, and for cats (x = 12.16%) between November and April (p < 0.05). Although the prevalences were generally higher during the summer months, no statistical differences were detectable when looking at the pattern between the four seasons, neither for dogs, nor for cats. Interestingly, the highest prevalences in dogs (9.9%) were detected in June 2004 and comparatively, in cats (23.86%) in August. The lowest detection rates in dogs were seen (1.28%) in April and in cats (7.26%) in January. The preliminary results did not indicate any tendency for a relationship between climatic conditions and flea infestation rates. Similarly, no differences of the infestations rates were detectable between urban and rural areas, 56% (dogs) and 46% (cats) of the infested pets originated from urban habitats. The flea species collected include Ctenocephalides felis, Ctenocephalides canis, Archaeopsylla erinacei, Pulex irritans, Ceratophyllus gallinae, etc. The overall frequencies reveal that C. felis was the most prominent species (81.5%), followed by C. canis (12.5%), A. erinacei (2.7%) and P. irritans (1.7%).

Animals↗