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This study is the first confirmation of Rickettsia felis in Australia. The organism was identified from 4 species of fleas obtained from dogs and cats in Western Australia, by using polymerase chain reaction amplification and DNA sequencing of the citrate synthase and outer membrane protein A genes.
During the 12-yr period, 1973-1984, 243 isolates of Pasteurella multocida were recovered or identified from specimens submitted for plague tests. Of the isolates, 79% were from rodents, 10% from lagomorphs, and 7% from carnivores; eight isolates were recovered from pools of rodent or carnivore fleas, and two were recovered from cat-bite wounds of human patients. No correlations of host or geographic sources, season, or biotypic or serotypic characteristics were found. Of the rodent strains serotyped, most were found to be serotypes 1A or 3A, which suggests a possible epizootiologic role for rodents in outbreaks of avian cholera that commonly involve these serotypes.
We have analyzed autosome, sex chromosome, and spindle behavior in spermatocytes of the flea beetle, Alagoasa bicolor. In this species, males have very large X and Y chromosomes, which, although they are never physically connected, always segregate to opposite spindle poles at anaphase I, thus preserving the sex ratio in the next generation. We find that the sex chromosomes are partitioned to a peripheral spindle domain early in prometaphase I and that their segregation can be accounted for mainly by their reorientation from the parallel to the linear configuration, and little by chromosome-to-pole movement. Further, the behavior of the autosomes and that of the sex chromosomes seem to have little to do with each other. Spindle elongation is minimal; barely segregating the large sex chromosomes into the daughter cells at telophase I.
The Indian model of plague transmission by Xenopsylla cheopis, discovered by P.L. Simond, has been largely adopted even though it is flawed. X. cheopis cannot be the primitive vector, for neither its nor the rats' cradle is the same as for plague. Furthermore, the insect's vital cycle is impaired by proventriculus blocking. The combination of three factors--the synathropic rat, X. cheopis and Yersinia pestis--coupled with man's seafaring was what led to the multiplication of plague foci. This in turn "created" the third pandemic only because the disease was thus spread to very diverse biogeographical zones. The perennial establishment of the cycle happened through the bacillus' adaptation to many endemic fleas and parasites of numerous endemic animals. Indeed, in many countries, X cheopis is not involved in the persistence of selvatic plague.
The resistance of Xenopsylla cheopis from urban area to pyrethroids, to DDT, and their susceptibility to carbamate are known. We have evaluated the susceptibility of X. cheopis collected from three rural localities: Ambodisiarivo (district of Antananarivo Avaradrano), Mandoto (district of Betafo), Analaroa (district of Anjozorobe) in the province of Antananarivo and in Besoa (district of Ambalavao) in the province of Fianarantsoa. The standard WHO protocol was used and four insecticides were tested: deltamethrin 0.025%, cyfluthrin 0.15% (pyrethroids), DDT 4% (organochlorine), propoxur 1% and bendiocarb 0.1% (carbamate). X. cheopis has been shown resistance to DDT 4%, to deltamethrin 0.025% but was susceptible in the rural area around Antananarivo City. They were tolerant to deltamethrin 0.025% and cyfluthrin 0.15% but susceptible to propoxur 0.1% and bendiocarbe 1% in the districts of Betafo and Anjozorobe. In Besoa, X. cheopis was resistant to DDT 4%, tolerant to deltamethrin 0.025% and cyfluthrin 0.15% but susceptible to propoxur 0.1% and bendiocarbe 1%. These results indicate that DDT and pyrethroids can not be recommended any more for the vector control in the rural area around the capital. The use of pyrethroids in the other districts of the central highland must be joined with a X. cheopis susceptibility control. In case of resistance to pyrethroids, carbamates would be proposed to control plague vector in the rural area. The high level of resistance to DDT and pyrethroid in the rural area around the capital confirms the importance of studying the flea population in different area of Madagascar and the possibility of the gene resistance propagation.
The genus Eumolpianus Smit, 1983, a group of fleas infesting chipmunks mostly in western North America, is reviewed. Its host preferences and distribution are discussed and the relationships of the 7 currently recognized species are examined. It is concluded that E. eumolpi americanus (Hubbard, 1950) is a junior synonym of the nominate species. Although not formally synonymized, it is postulated, based on morphology and geographic distribution, that E. eutamiadis (Augustson, 1942) and E. fornacis (Jordan, 1937) are conspecific, as are E. orarius (Johnson, 1961) and E. wallowensis (Hubbard, 1947) with E. cyrturus (Jordan, 1929). The status of E. polumus (Traub & Johnson, 1952) remains uncertain, but it is evidently a member of the E. cyrturus-group.
Based on the idea of life table, the concept and index of insect pests accumulated damage amount were described and the damage degree and its fluctuation were compared. Through analyzing the deterrent effect of azadirachtin on the adults of striped flea beetle (SFB), Phyllotreta striolata (F.), the results showed that the control mechanism was its strongly deterrent effect. When 0.5 ml.L-1 azadirachtin was applied, 83.75% of the SFB adults was kept away from the host plant. The population trend index (I-value) of SFB decreased from 3.8680 in the control to 0.3354. The interference index of population control (IIPC) was 0.0863 at this dosage. The results come from the fields, which avoided the space limit of laboratory experiment, were the main basis to evaluate the deterrent of allogenetic plant secondary substances to insect pests. Such index provided an objective method to assess the pest damage degree, and would play an important role in the dynamic researches of pest ecological control.
Fleas of Xenopsylla gerbilli and Xenopsylla hirtipes, parasites of Rhombonus optimus in the Kizil--Kum, have a sympathric distribution. Within a greater part of their common area both species vicariate in landscapes: X. hirtipes occupties more mesophilous parts while X. gerbilli is distributed in all parts where the first species is missing. The distribution of X. hirtipes depends first of all on abiotic environmental factors and that of X. gerbilli--on biotic ones, i. e. on the competition with X. hirtipes. However, under more favourable conditions (northern foothill valleys of the Bukantau ridge) both species occur together in great number.
The four species of fleas associated with birds in West Siberian Plain have been recorded. Ceratophyllus styx is a specific parasite of Riparia riparia. Ceratophyllus garei, C. gallinae, and C. tribulis parasitize various setting of birds.
The authors recently described a new species of sand flea (genus Tunga) occurred in goat, sheep, cow, pig and man, in the Andean village of S.ta Isabel (Ecuador) and named Tunga trimamillata. Its most important morphological characteristics are: slightly larger dimensions than T. penetrans, both in male and female; presence on the anterior extremity of gravid female of three rounded humps surrounding head and thorax; length of the first segment of maxillary palpi which is longer than each of the other three. The importance of this parasite is due to the fact that it can cause the same damages as T. penetrans both in humans and domestic animals, with conseguent walking difficulties and local or generalized infections. For breeders, economic losses can be remarkable. Tungiasis is a serious problem of Public Health in many countries of Latin America and Subsaharian Africa, and it can be considered in these localities as an indicator of underdevelopment and poor hygiene conditions.
A new aspect of insecticide action of synthetic pyrethroid "Decis" as a system poison for wild rodent flea control is discussed. Rapid decay of the insecticide gives an opportunity to use it in grain baits in the natural foci of plague.
Ceratophyllus vagabundus insularis was recorded in all typical nesting cliffs in mainland Norway in nests of puffins, shags, cormorants, and kittiwakes, but not in nests of gulls. Ceratophyllus vagabundus vagabundus was recorded in Spitzbergen associated with geese and gulls. Ceratophyllus garei, the only flea species in Larus gull's nests, was present in small numbers in nests of kittiwakes and shags in the southern part of the investigation area. Mioctenopsylla arctica arctica was recorded in kittiwake nests on Spitzbergen and in one nesting cliff in the most arctic part of mainland Norway, where it also was the dominating species. C. vagabundus was reported to attack man.
The fleas of C. tesquorum are characterized by high protease activity in the epithelium and contents of the stomach, quick hemolysis of erythrocytes and low blood coagulation. Rare blockformation in C. tesquorum and its long terms under experimental conditions are apparently associated with changes in the quantity of plague microbes in the digestive tract depending on the stage of blood digestion: reduced during the hemolysis of erythrocytes and increased when it was over.
Seasonal changes in the female age composition of micropopulations of X. skrjabini are described. The descriptions are based on observations conducted within a period of 1971-1976. The comparison of females' age with the time of mass egg laying and the data on the developmental cycle rate (from egg to imago) suggests that in Mangyshlak fleas of X. skrjabini have four generations a year. The second, third and fourth generations parasitise at the end of summer or early in autumn. The third and fourth generations hibernate in the quiescence state, begin reproducting in the spring of the next year and in June give start on the first summer generation.
Seven fleas species were revealed on Apodemus uralensis. Only three of them (Ctenophthalmus agyrtes, Ct. uncinatus, Megabothris turbidus) are the main parasites of this rodent species and have similar phenology of imago. They appear in April, parasitise during spring and summer periods and disappear in autumn, in September-October. The abundance of all three species shows two peaks in a year, which correspond to two generations. Four species (Amalaraeus penicilliger, Ct. bisoctodentatus, Peromyscopsylla bidentata, P. silvatica) are not peculiar to Apodemus uralensis. They pass on this host species occasionally from other animals inhabiting forest biotopes.
Fleas collected in Algeria in the district of Oran between July and September 2003 were tested by polymerase chain reaction for the presence of Rickettsia spp. DNA using primers amplifying gltA and OmpA genes. Two gltA sequences identical to those of an emerging pathogen, Rickettsia felis, were detected including i) R. felis California 2 in Ctenocephalides canis from rodents and ii) R. felis RF2125 in Archeopsylla erinacei from hedgehogs.
The patterns of esterase (Est) isoenzyme of 3 flea species were studied by vertical slab polyacrylamide gel electrophoresis (PAGE). The samples prepared from the third larval instar, female and male (the unsucking and sucked one) were run in the same gel slab. The result was as follows: Xenopsylla cheopis showed 14 bands, with 5-6 major bands, Ctenocephalides felis felis showed 9 bands with 4-5 major bands and Nosopsyllus laeviceps kuzenkovi showed 9 bands with 4-5 major bands. These three species have their common bands as well as respective specific bands. The difference in Est isoenzymogram among families was greater than among genera, displaying a species-specific feature.
A commercial flea and tick product containing 9.0% fenvalerate for use in dogs and cats was suspected of causing illness. An acute toxicity study was performed in 10 dogs and 10 cats exposed to the product orally (po) and dermally at differing doses. Samples were obtained for DEET and fenvalerate analysis. Oral dosing of dogs and cats produced severe clinical illness at doses as low as 0.66% of a can (7 ounce spray can)/kg body weight. Dermal application of the product resulted in minor clinical abnormalities in dogs. Oral exposure at 0.5% can/kg body weight resulted in severe illness, and dermal application caused severe illness or death in cats at 20% and 40% of a can/kg body weight. The cats receiving 10% of a can/kg body weight dermally became depressed for several hours but recovered uneventfully. Serum DEET concentrations closely paralleled the clinical signs observed in the animals. Serum concentrations of DEET above 20 ppm were considered diagnostic for intoxication. Urine concentrations of DEET above 1 ppm and tissue (liver, bile, and kidney) concentrations of DEET above 10 ppm were supportive of poisoning; values near 100 ppm were diagnostic for fatal poisoning.