Persistence of Yersinia pestis in Soil Under Natural Conditions

As part of a fatal human plague case investigation, we showed that the plague bacterium, Yersinia pestis, can survive for at least 24 days in contaminated soil under natural conditions. These results have implications for defining plague foci, persistence, transmission, and bioremediation after a natural or intentional exposure to Y. pestis

Ecology and Geography of Plague Transmission Areas in Northeastern Brazil

Plague in Brazil is poorly known and now rarely seen, so studies of its ecology are difficult. We used ecological niche models of historical (1966-present) records of human plague cases across northeastern Brazil to assess hypotheses regarding environmental correlates of plague occurrences across the region. Results indicate that the apparently focal distribution of plague in northeastern Brazil is indeed discontinuous, and that the causes of the discontinuity are not necessarily only related to elevation—rather, a diversity of environmental dimensions correlate to presence of plague foci in the region. Perhaps most interesting is that suitable areas for plague show marked seasonal variation in photosynthetic mass, with peaks in April and May, suggesting links to particular land cover types. Next steps in this line of research will require more detailed and specific examination of reservoir ecology and natural history

Plague and Climate: Scales Matter

Plague is enzootic in wildlife populations of small mammals in central and eastern Asia, Africa, South and North America, and has been recognized recently as a reemerging threat to humans. Its causative agent Yersinia pestis relies on wild rodent hosts and flea vectors for its maintenance in nature. Climate influences all three components (i.e., bacteria, vectors, and hosts) of the plague system and is a likely factor to explain some of plague's variability from small and regional to large scales. Here, we review effects of climate variables on plague hosts and vectors from individual or population scales to studies on the whole plague system at a large scale. Upscaled versions of small-scale processes are often invoked to explain plague variability in time and space at larger scales, presumably because similar scale-independent mechanisms underlie these relationships. This linearity assumption is discussed in the light of recent research that suggests some of its limitations

Prevention des Rickettsioses

;rhe di~cove!y of antibiotics having an highly effective and specific action on th~ rickettsial diseases has greatly' deprived of importance the formerly outstanding prevention of these diseases. However, the prevention of Typhus: fever, the single rickettsiosis to be purely human and the <;>nly. one to: be epidemic, remains an important problem. The methods of. prevention.m the mveterate foci 'can be determined in the light of the last attainments, WhICh are: non-transmission of the infection by the bite of the louse, ~pread by the dusty faeces of the ectoparasite, long-lived conservation of the VIruS ~ that dust, possibility of lasting latency in man and of resurgences from the earne

Prevention Immediate de la Rage chez L'homme Apres Morsure en Iran

A new and efficient organization of the early preventron of rabies in man can be proposed thanks to the serum prepared by the Razi Insti~ute in the dried form. This serum, highly concentrated, has therefore an outstanding potency, but a complete innocuity; its dry state allows a perfect c~nservation without special precautions. All medical centers, e.ven the m?st re~ote m the parts Of,the country where rabies remains enzootic, WIll be provided WIth a reserve of this serum, so that eventlhe peasants of the most distant vmages can receive the saving injection .in time, i.e. during the seventy two hours after the inoculation of the virus by the biting animal. Under the protection of the serum the sending of the wounded tow~rds Teheran is 'not, as in the past, a dramatic emergency and would be avoided in many cases. ThLis paper gives then to the physicians the necessary hints, not only for the use of the serum and the wound treatment, but also for the observation of the wounded and of the biting animal