Cases of childhood diarrhoea in Africa linked to the climate phenomenon in La Niña

A curious discovery was made by researchers at Columbia University’s Mailman School of Public Health. The researchers, conducting a study in Botswana, found that spikes in childhood diarrhea are associated with climatic conditions related to the La Niña phenomenon.

Diarrhea can be fatal in low and middle income countries with underdeveloped medical networks, especially in children under the age of five. In Africa, diarrhea rates in children under five are particularly high and account for 1/4 of all deaths caused by diarrhea.

Researchers have found a connection with the La Niña phenomenon. The latter is an atmospheric phenomenon linked to the larger phenomenon called El Niño-Southern Oscillation (ENSO), an irregular variation in the winds and surface temperatures of the oceans in the tropical eastern Pacific area.

ENSO is linked to both La Niña and El Niño: with the former, the ocean temperatures are warmer and with the latter colder. This phenomenon can affect weather conditions in various parts of the world such as temperature, wind and precipitation.

Analyzing statistics on childhood diarrhea (the one that affects children under five) in the Chobe region of northeastern Botswana, researchers have found that the La Niña phenomenon is associated with colder temperatures, increased rainfall and more frequent flooding in the same rainy season.

This same climatic phenomenon, as the researchers found, is associated with a 30% increase in the incidence of childhood diarrhea in the rainy season from December to February.

According to Alexandra K. Heaney, a researcher at the University of California at Berkeley, one of the authors of the study, the results of this research show that the phenomenon of ENSO can be used as a medium-long term forecasting tool for the spread of childhood diarrhea in southern Africa.

Specifically, when this climate phenomenon advances, it would be appropriate to accumulate more medical supplies, such as hospital beds, and more health workers in these areas to manage the increased incidence of this childhood disease.

Diarrhea can be caused by many different pathogens, including viruses, protozoa bacteria, and exposure to these pathogens itself can be facilitated by weather conditions: more rain and flooding means more contact with water, which is an ideal vector for some of these pathogens.

Dragging effect of space-time detected in white pulsar-dwarf system

If a very massive object, such as a planet or star, rotates, it literally drags the surrounding space-time with it. It is a phenomenon predicted by Einstein’s general relativity also known as the “dragging effect” or the Lense-Thirring effect (from the two Austrian physicists Josef Lense and Hans Thirring who in 1918 first derived the effect within general relativity).

This effect also exists on Earth in relation to its proximity to the Sun but in our case, it is extremely small so that it has been very difficult to measure for years. The effect, however, is more pronounced with heavier and more massive objects, such as white dwarfs or neutron stars. And it is by studying a binary system composed of a white dwarf and a pulsar that researchers have found direct evidence of this effect.

The researchers, led by Vivek Venkatraman Krishnan of the Max-Planck-Institut für Radioastronomie, have in fact observed a pulsar characterized by a narrow and fast orbit around a white dwarf that has a mass similar to that of the Sun. The pulsar makes a full circle around this white dwarf in less than five hours, whizzing at a speed of over one million km/h. The two bodies are very close together and less than the diameter of the Sun.

Measuring the timing of the arrival of the very short pulses of the pulsar towards Earth, data found over a period of almost twenty years, the researchers concluded that it is the Lense-Thirring effect that causes a sort of drift, slow and long term, of the way in which the pulsar and the white dwarf orbit around each other.

It is the dragging of the same space-time that causes the orientation of the pulsar to slowly change while it revolves around the white dwarf. Among other things, this new study confirms a hypothesis, contained in other previous studies, according to which white dwarf of this binary system, called PSR J1141-6545, was formed before the pulsar. Such binary systems are considered quite rare.

This study, among other things, could also be useful to understand what is inside a white dwarf: despite decades of research, it is not yet known how matter is arranged inside this very strange cosmic object given the conditions inside it, conditions of very strong gravity to which the same matter is subjected and which are not reproducible in the laboratory.