Ecological community structure is particularly important in vector-borne zoonotic diseases with complex life cycles. Qualitative community model analysis may provide a meaningful alternative to standard population-based models of vector-borne disease. We built on recent mathematical developments in qualitative community modeling coupled with conventional biomathematical models of vector-borne d...

The viability of pneumococcus, Type I, sprayed into the atmosphere from a liquid suspension was measured as a function of the relative humidity. When broth, saliva, or 0.5 per cent saline solution is employed as the suspending medium, a very high mortality rate is observed at relative humidities in the vicinity of 50 per cent. However, at humidities above or below this value the microorganisms ...

All manned spacecraft are vulnerable to leaks generated by micrometeorite or debris impacts. Methods for locating such leaks using leak-generated, structure-borne ultrasonic noise are discussed and demonstrated. Cross-correlations of ultrasonic noise waveforms from a leak into vacuum are used to find the location of the leak. Four methods for sensing and processing leak noise have been develope...

In a series of publications which have appeared during the last five years (1-8), the activity of certain organic compounds, particularly propylene and triethylene glycols, in killing air-borne bacteria and viruses has been described. The types of microorganisms found to be susceptible and some effects on this killing action of changes in the temperature, relative humidity, and concentration of...

Manganese is an essential trace element which is toxic in high doses. Over the past several decades, manganese has replaced lead as the anti-knock agent in gasoline, raising concern about air and road-side contamination with this element. In addition, manganese is absorbed by the liver, making specific populations (e.g., pregnant women, infants and children, and patients with liver disease) sus...

The history of the main bovine tick-borne diseases occurring in South Africa and the role Onderstepoort played in their identification and control is briefly reviewed. The present attitudes regarding the control of tick-borne diseases, taking into account their complexity, is discussed. Gaps in our knowledge regarding heartwater epizootiology and possible future studies are defined.

INTRODUCTION Dengue in Africa is underreported. Simultaneous reports of travellers with dengue returning from Luanda, Angola, to six countries on four continents suggest that a major dengue outbreak is currently occurring in Angola, South West Africa. METHODS To identify the origin of the imported dengue virus, we sequenced the virus from Angola and investigated the interconnectivity via air ...