Human plague in the United States.
To the Editor:— The Aug 5, 1962 issue ofThe Journalcarried a cover picture of a painting by Arnold Bocklin entitled "Plague" and an article entitled "Human Plague in the United States" by Caten and Kartman. This article and the caption next to the cover picture carry misleading statements which I would like to call to your attention. Discussing the distribution of wild-rodent plague in the United States, Caten and Kartman state, "The reason why plague does not extend beyond the 100th meridian is poorly understood." While it is true that all human cases associated with wild rodents for which adequate data are available have been acquired west of the 100th meridian, and this corresponds quite well to the known distribution of wild-rodent plague, as shown by Caten and Kartman, very limited surveys of wild rodents and fleas for plague have been conducted east of the 100th meridian. 1 Many investigators believe that wild-rodent plague does not extend into the eastern states, largely on the basis of the distribution of human cases associated with wild rodents. On the other hand, plague-infected wild rodents or their ectoparasites have been identified from over 130 counties in the western
Exploring and Mitigating Plague for One Health Purposes
In 2020, the Appropriations Committee for the U.S. House of Representatives directed the CDC to develop a national One Health framework to combat zoonotic diseases, including sylvatic plague, which is caused by the flea-borne bacterium Yersinia pestis. This review builds upon that multisectoral objective. We aim to increase awareness of Y. pestis and to highlight examples of plague mitigation for One Health purposes (i.e., to achieve optimal health outcomes for people, animals, plants, and their shared environment). We draw primarily upon examples from the USA, but also discuss research from Madagascar and Uganda where relevant, as Y. pestis has emerged as a zoonotic threat in those foci. Historically, the bulk of plague research has been directed at the disease in humans. This is not surprising, given that Y. pestis is a scourge of human history. Nevertheless, the ecology of Y. pestis is inextricably linked to other mammals and fleas under natural conditions. Accumulating evidence demonstrates Y. pestis is an unrelenting threat to multiple ecosystems, where the bacterium is capable of significantly reducing native species abundance and diversity while altering competitive and trophic relationships, food web connections, and nutrient cycles. In doing so, Y. pestis transforms ecosystems, causing “shifting baselines syndrome” in humans, where there is a gradual shift in the accepted norms for the condition of the natural environment. Eradication of Y. pestis in nature is difficult to impossible, but effective mitigation is achievable; we discuss flea vector control and One Health implications in this context. There is an acute need to rapidly expand research on Y. pestis, across multiple host and flea species and varied ecosystems of the Western US and abroad, for human and environmental health purposes. The fate of many wildlife species hangs in the balance, and the implications for humans are profound in some regions. Collaborative multisectoral research is needed to define the scope of the problem in each epidemiological context and to identify, refine, and implement appropriate and effective mitigation practices.
Chemical-Looping Combustion of Biomass in a 10 kWth Reactor with Iron Oxide As an Oxygen Carrier
Chemical-looping combustion of biomass was carried out in a 10 kWth reactor with iron oxide as an oxygen carrier. A total 30 h of test was achieved with the same batch of iron oxide oxygen carrier. The effect of the fuel reactor temperature on gas composition of the fuel reactor and the air reactor, the proportion of biomass carbon reacting in the fuel reactor, and the conversion of biomass carbon to CO2 in the fuel reactor was experimentally investigated. The results showed that the CO production from biomass gasification with CO2 was more temperature dependent than the CO oxidation with iron oxide in the fuel reactor, and an increase in the fuel reactor temperature produced a higher increase for the CO production from biomass gasification than for the oxidation of CO by iron oxide. Although the conversion of biomass carbon to CO2 in the fuel reactor decreased with the increase of the fuel reactor temperature, there was a substantial increase in the proportion of biomass carbon reacting in the fuel react...