A leap forward in understanding cholera
Cholera remains a public health problem in countries without access to safe drinking water and adequate sanitation. Researchers are trying to come up with theoretical models for cholera that allow them to understand how an outbreak happens, how it can best be contained, and how it might be prevented. Until now, the existing cholera models have not been able to describe and explain actual outbreaks very well. Taking new experimental data into account, David Hartley and colleagues (of the University of Maryland) now report a major advance in cholera modelling in the international open-access medical journal PLoS Medicine.
Caption: Scanning electron micropgaph of Vibrio cholerae. (Photo: Hartley et al.)
Transmission electron micrograph of Vibrio cholerae. (Photo: Hartley et al.)
In 2002, Andrew Camilli and colleagues reported that cholera bacteria isolated from the stools of sick patients were much more infectious than those found in contaminated water. (They compared the two by exposing mice to a mix and determining which bacteria made the mice sick.) Those researchers proposed that the infection of a human patient (i.e., the exposure to an environment that is quite different from their regular freshwater ponds) changes the cholera bacteria. As a result, for a short period of time, the bacteria become more infectious.
The study caught the attention of David Hartley and colleagues, who saw a chance to improve the modeling of cholera epidemics. Hartley was interested because Camillis results shed new light on a fundamental question in cholera epidemiology: what is the relative importance of human-to-human infection(i.e. fecal to oral) versus environment-to-human infection (through contaminated food or water)? If the infective dose of bacteria that have become hyperinfectious because of recent passage through a human host is much lower than that of bacteria from the environment, this would support a crucial role of human-to-human transmission in cholera epidemics.
Hartley and colleagues found that incorporation of the existence of a hyperinfectious state into their models resulted in a much better fit with the observed explosive epidemic patterns of past cholera outbreaks. On one hand, this result lends theoretical support for Camillis results and suggests that his findings in laboratory animals have clinical relevance. On the other, it strongly suggests that human-to-human transmission is crucial for cholera epidemics and pandemics, and that health measures must focus on minimizing the risk of transmission of the short-lived hyperinfectious form of the bacterium. There is also the intriguing possibility that similar hyperinfectious states exist for other bacteria, something that seems well-worth exploring.
Paul Ocampo | EurekAlert!
The most recent press releases about innovation >>>
Die letzten 5 Focus-News des innovations-reports im Überblick:
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Mapping the interaction of a single atom with a single photon may inform design of quantum devices
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...