Onchocerciasis: The Pre-control Association between Prevalence of Palpable Nodules and Skin Microfilariae

*Background*: The prospect of eliminating onchocerciasis from Africa by mass treatment with ivermectin has been rejuvenated following recent successes in foci in Mali, Nigeria and Senegal. Elimination prospects depend strongly on local transmission conditions and therefore on pre-control infection levels. Pre-control infection levels in Africa have been mapped largely by means of nodule palpation of adult males, a relatively crude method for detecting infection. We investigated how informative pre-control nodule prevalence data are for estimating the pre-control prevalence of

Transient ocean warming and shifts in carbon reservoirs during the early Danian

The Palaeocene–Eocene Thermal Maximum (PETM) at 55 Ma marks the Palaeocene/Eocene (P/E) boundary and represents a discrete period of abrupt, transient global warming. There are few vegetation records from within the PETM and such an absence of data prevents modelling of the vegetation response to climate warming. Outcrops exposing the Sentinel Butte member (upper Fort Union Formation) and the Golden Valley Formation (Bear Den and lower Camels Butte members) within the Williston Basin of western North Dakota, USA are known to span the P/E boundary. Pollen and spore floras at the Farmers Butte locality (Stark County, North Dakota; 46.92° N 102.11° W) record changes in abundance of some reed, fern and understorey plants across the Sentinel Butte–Bear Den contact but no other composition changes occur until the arrival of Eocene immigrants Platycarya spp. (walnut/pecan family) and Intratriporopollenites instructus (linden/sterculia/cotton tree families) at the top of the Bear Den member, c. 11 m above the change in co-occurrence and relative abundance patterns of range-through taxa. The exact stratigraphic level at which these Eocene marker taxa first occur is unclear owing to the heavily weathered nature of Bear Den strata below the Alamo Bluff lignite. This pattern of stratigraphic change may be correlative to the well documented “floral gap” of PETM records in Wyoming. Though bulk ?13Corg ratios decrease by 2.4‰ across the Alamo Bluff lignite, degradation of organic carbon within the upper Bear Den member partially masks full expression of the carbon isotope excursion associated with the PETM. Hence, strata around the Alamo Bluff lignite may represent a new terrestrial record of the PETM. In agreement with terrestrial PETM records from other U.S. western interior localities, palynological data indicate no floral extinction and little composition change across the Palaeocene/Eocene boundary. <br/