Plague Fleas Research Articles

Human factors caused the third plague epidemic in Harbin

The third plague epidemic in Harbin broke out in 1946 and ended in 1954. Different from the first two plague epidemics (imported), the third prevalence was both imported and idiopathic infectious disease which was caused by human factors. Japanese troops set forbidden zones to build a biological weapon center, which destroyed the natural environment and offered a good growth condition for Citellus Undulatus. In 1945, on the eve of surrender, the Japanese blew up the Unit 731 germ factory located in a bungalow district, which caused diffusion of infected plague fleas. Mice of the district were infected and a man-made plague focus was created. During the prevalence of the third plague, prevention departments at all levels took a series of actions and with people's efforts, the plague was effectively controlled.

Editorial [Hot Topic: In Silico (Guest Editor: Alexandre G. de Brevern)

Coming from Crimea, the Black Death spread to Western Europe and North Africa during the 1340s. From 1346 to 1352, the plague killed an estimated 25–40% of Europeans of all age-groups [1], i.e. 30 to 60% of Europe population. One of the earliest and most widely accepted explanations was that God was punishing humanity for their sins. One remedy for the curse was to do penitence. Thus in 1348 there rapidly arose a mass movement of flagellation [2]. In fact flagellation could not really help against such threat. The Black Death or Bubonic plague is caused by Yersinia pestis, a Eubacteria discovered in 1894 by Alexandre Yersin. It is transmitted by the bite of the flea Xenopsylla cheopsis. This flea lives by feeding the blood of many species besides man but its most preferred relationship is with the black rat (Rattus rattus). Fossilized remains of the plague flea have been found in large numbers in Amarna, Egypt [3, 4] about 1350 BC, and thus could be directly linked to the events described in the Book of Samuel [5, 6]. During the epidemic of Bubonic plague in London in 1665–1666, the known treatments were made use of, e.g. the so-famous Theriac or Venice Treacle which is used from the time of ancient Rome as a remedy against poison [7]. Since then, more specialized and novel treatments have been developed. However, since the characterization of Yersinia pestis, numerous drugs have been developed against it, e.g. gentamicin or doxycycline [8].. These researches had been carried out using more elaborated biochemical, biophysical and biological approaches.

Bubonic plague in the Book of Samuel

In 2000 the pages of the JRSM saw an intriguing exchange concerning an illness described in the Hebrew Bible. The story in 1 Samuel is that the Philistines, having captured the Ark of the Lord from the Israelites, experienced an outbreak of ‘tumours’ (Hebrew ophal), and the affliction followed them as they moved the Ark from city to city. Concluding that the Ark was responsible for this disaster, the leaders decided to return it to the Israelites along with a guilt offering of five golden tumours and five golden rodents (akbar). But soon after the arrival of these ‘statues’ (probably small wooden models covered with gold) in Beth-shemesh seventy Israelites died in that city. Evaluating this epidemic, JP Griffin1 concluded that the outbreak was plague, with its associated buboes. But WMS Russell2 responded that Griffin was ‘certainly erroneous’ because of a mistranslation (the tumours being haemorrhoids due to dysentery) and because the rat carrier of plague was not in the region at the time of the described events. Since then, advances in archaeology have shifted the weight of evidence towards Griffin; moreover, the ‘emerods’ of the King James Bible appear in all modern translations as tumours. Bubonic plague, caused by Yersinia pestis, is transmitted by the bite of the flea Xenopsylla cheopsis. This flea lives off the blood of many species besides man but its most notorious relationship is with the black rat (Rattus rattus). Recent archaeological evidence has caused a rethinking of plague in the ancient Near East. Fossilized remains of the plague flea have been found in large numbers in Amarna, Egypt;3 and, since Amarna was occupied for only a few years, we can date this contact between human beings and plague fleas accurately to about 1350 BC—which is before the events described in the Book of Samuel. Moreover, archaeological studies in the Nile Valley indicate that R. rattus was introduced at this time, probably via ships from India. Evidence of bubonic plague has not been seen in Egyptian mummies but all the vectors were in place.4 These vectors could have spread a few miles north to Philistia. From the story, it seems that the most characteristic features of the epidemic were rats and tumours. Dead rats, killed by the same bacillus that kills human beings, are seen in the streets of plague towns; and enlarged lymph nodes in the groin and axillae are the most obvious features of the illness. Why did the Philistines send statues of rodents and tumours to their neighbours? One interpretation is that the Philistines were offering a friendly warning: ‘We have experienced an epidemic and these are the things you should look out for’. Another is that the statues represented the essence of the judgment that had descended upon the Philistines, who hoped that the affliction would be passed on. The above analysis assumes that the story of the epidemic, as told in 1 Samuel, is based on an actual occurrence. A widespread view is that biblical stories of this sort are the product of a religious reform movement that flourished hundreds of years after Samuel, in the late Iron Age; but it is acknowledged, nonetheless, that they may have historical kernels.5 The kernel here is large enough to indicate that, even if the account is fictitious, it is based on a personal knowledge of plague.

Distribution and insecticide resistance of the plague flea Xenopsylla cheopis in Maharashtra State, India

Distributions are reported for commensal rat fleas, predominantly Xenopsylla cheopis (Rothschild), in the State of Maharashtra, India, including the city of Bombay, during 1965-80. The X.cheopis flea index was high in most parts of Maharashtra, but low in Bombay. Rattus rattus Linnaeus is the principal host of X.cheopis, but the host range includes Bandicota bengalensis Gray, Golunda ellioti Gray, Mus musculus Linnaeus, Rattus blandfordi Thomas, R. norvegicus Berkenhout, Suncus caerulaeus Lerr, S. murinus Linnaeus and Tatera indica Hardwicke. X.cheopis was found to have high degrees of resistance to DDT, malathion and fenthion, tolerance to gamma HCH (= gamma BCH) but susceptibility to dieldrin. This insecticide resistance situation may contribute to the high flea indices prevailing in the state, with consequent risks of plague outbreaks. Two other species of rat flea, X.astia Rothschild and X.brasiliensis (Baker) were found to be less common than previously recorded. Their apparent replacement by X.cheopis is tentatively attributed, at least partly, to the selective advantage of insecticide resistance in the latter species.

The truth about saturation deficiency—an historical perspective

AbstractStudies on the water relationships of arthropods originated from the needs of applied entomology early in this century. Saturation deficiency (S.D.) was hailed as a measure whereby the effects of temperature and humidity on transpiration, and thus on development and longevity, could be simply combined. Errors in curve fitting and lack of physiological knowledge led to early misconceptions, but S.D. helped to focus attention on the need for laboratory analysis of field data and played a part in the move toward a more scientific approach leading to a great expansion of the whole field. Application of the concept to arthropods has usually been controversial, and examples of this drawn from the literature on the bionomics of the plague fleas and on cuticular waterproofing are discussed. A controversy exists at present concerning S.D. and the physics of transpiration. The concept of S.D. has been most useful where it has stimulated research to find out how arthopods avoid its consequences.

An Abnormal Form of Female Rat Flea, Xenopsylla Cheopis Roths.

ROTHSCHILD, in 1911, separated the three species of fleas, X. cheopis, X. astia and X. brasiliensis of the genus Xenopsylla found on rats. X. cheopis is widely distributed in the tropics and is the principal plague flea in India. The three species (♀♀)mentioned here can be easily identified by the shape of the spermatheca. Until now, it has been reported that X. cheopis has a single spermatheca1–3 (Fig. 1).

Serological criteria of species

HERE is no need to remind a medical audience that treatment can be considered only after diagnosis. Should the disease be caused by some pathogenic micro-organism it is essential to determine accurately the species involved. The kernel of many problems in zoology, including a number of problems in medical zoology, has been, and indeed still is, the recognition of the species involved. Applied biology can be a science only if based on sound systematics. Sometimes the recognition of valid species needs little effort. Only the G.P.I. would confuse elephant and rat, but on the other hand, even the most sober and erudite might have difficulty in distinguishing the common rat fleas, or even fail to realise there was more than one species of rat flea. When it became clear that plague was a zoonosis, transmissable by fleas from the natural rat reservoirs, the Plague Commission was puzzled by the fact that outbreaks of plague never lasted long in Colombo and Madras, despite the abundance of rats and rat fleas. The problem was solved by Lord Rothschild who found that the flea normally occurring on rats in these cities was Xenopsylla astia Roths., a species similar to but separate from the plague flea X. cheopis Roths., and unlike it, a very poor vector of plague. A calculation of the number of individuals of the common rat flea of this country which one would have to examine: to find two specimens with identical chaetotaxy produces a figure of several billions, far more than the total population of these fleas in Ireland (Rothschild, 1932). Where between this extreme and that of a genus does one draw the line that indicates a species ? This brings us at once to the question of what is a species. This is truly a $64,000 question: the answer is already known, in practice if not in theory, by any person one is likely to want to question about the matter. What is this answer ? "A species is what a competent sys

Plague Fleas, with special reference to the Milroy Lectures, 1924.

The geographical distribution of the different species of rat flea is one of the most important factors governing the spread of plague.Xenopsylla cheopis is the most effective transmitter of both epidemic and epizootic bubonic plague in all parts of the world.The relative immunity of certain parts of India and Ceylon from plague is to be primarily attributed to the prevalence of an inefficient plague-carrying flea on the rats of these localities, viz. Xenopsylla astia.Climatic conditions play only a secondary part in limiting the spread of the disease in these relatively plague-free localities.Plague infection can be maintained in such localities by the importation of cheopis-infested merchandise.Climate does not exert an equal effect upon the transmitting power of different species of flea.Numerous attempts to transmit plague from rat to rat by means of X. astia at room temperature during the plague season in Colombo have all failed. X. astia, however, can carry plague from rat to rat under climatic conditions favourable to plague transmission. Continuous transmission of plague from rat to rat has been obtained with X. cheopis in Colombo under exceptionally unfavourable climatic conditions.Both plague and X. cheopis have a very irregular distribution within limits of Colombo City. The coefficient of correlation between two periods of human plague incidence and percentage of cheopis to total rat fleas of all species in 14 districts of the city is ·95, probable error ± ·02 for both periods.There is a close relation between premises infested with X. cheopis and premises where plague-infected rats are found.A three-fold relationship exists between the amount of imported grain, the prevalence of cheopis on rats, and the incidence of plague in the localities where grain is stored in Colombo.The measures so far devised for combating plague among Oriental populations, tolerant of all forms of animal life, have not proved conspicuously successful.Due recognition of the importance of the flea species factor should lead to marked improvement in plague preventive measures in many parts of the world.A rat flea survey of all the principal plague areas, especially the ports, becomes urgently necessary.The exports from localities where X. cheopis is found to be prevalent upon the rats should be considered actively dangerous when the locality is plague infected, and potentially dangerous even if it is plague free, since the continual importation of cheopis into a locality where this flea is not indigenous may eventually result in the extension of plague infection to a new area.I agree with Glen Liston and Norman White, that the export of produce, especially grain, from plague-infected ports should be controlled by international agreement.The limitation of imported cheopis and plague to definite zones in such localities as Colombo greatly facilitates the task of plague prevention, since all available resources can be concentrated simultaneously, or successively, on the infected areas.In such instances it is possible to mark out the potentially plague-infected zones by the simple and accurate method of surveying the rat fleas.Ten years have now elapsed since I tentatively put forward the suggestion that the spread of epizootic plague in the East Indies might be governed by the flea species factor. At first I adopted a cautious attitude towards my own hypothesis. I believe that the evidence now available warrants its acceptance by epidemiologists without further hesitation.If so, the discovery is but further testimony to the essential unity of science in its bearings on the welfare of the human race, for it is the natural outcome of the purely zoological researches of Rothschild and Jordan on the systemics of the Siphonaptera.

Insetti delle Case e dell' Uomo e Malattie che diffondono

PROF. BERLESE'S interesting manual deals with the insects and arachnids found in Europe attack ing man or damaging his food and belongings. After considering those-lice, bugs, fleas, mos quitoes, Phlebotomus, Stomoxys, and ticks-which suck the blood of man, he proceeds in the two following chapters to give an account of house-flies, blowflies, etc., and of such household pests as cockroaches, psocids, Lepisma, moths, and mites. Under most of the species there is a short description of the adult and of the life-history and habits, and suggestions for the application of deterrents and destructive agents. In several cases, e.g. the plague flea, the characters are too briefly given to be of much service.

THE PLAGUE FLEA AND ITS DESTRUCTION,

THE PLAGUE FLEA AND ITS DESTRUCTION,