Destruction of animal habitats due to human activities under the comprehensive name of "development" and extinction of species all over the world, are not only a problem in the field of ecology. Environmental damage endangers human health
Humans, in their actions, are a decisive factor in global warming, but they also largely contribute to the emergence of new and dangerous diseases.
Destruction of animal habitats due to human activities under the comprehensive name of "development" and extinction of species all over the world, are not only a problem in the field of ecology. The environmental damage endangers the health of humanity as a whole, because parasites then become "evolutionary minefields", as Canadian scientist, parasitologist Dr. Daniel Brooks of the University of Toronto warned a few days ago.
He claims that the retreat that occurred in what is known as "biological diversity", meaning a decrease in the variety of living creatures on the planet, is connected with the appearance of new human diseases such as West Nile fever and bird flu.
"The crisis of biological diversity does not only concern the extinction of animal species," stated Dr. Brooks, who is behind pioneering research on parasites. "In the past, when there were isolated cases, episodes, of major climate changes or widespread waves of extinction of species and animals began to move from their natural habitats, from areas where they lived to new areas, this process resulted in the appearance of new diseases.
Parasites migrated together with the animals that hosted them, to new areas, literally jumped into ships that sailed across the seas, arrived at new settlements, and found them new lodgings. The result: diseases that in many places were not known before.
The Canadian scientist presented the findings of his research a few days ago at the American Association for Advanced Science conference, during which an expert discussion on environmental statistics was held.
Dr. Brooks' research, which lasted more than a decade, was conducted in the dense jungles of Costa Rica where he collected samples of parasites. In one area, the Guanacaste Reserve in northwestern Costa Rica, on an area of 1000 square kilometers, habitats for many animals as well as rainforests and savannas are concentrated, an area where there are about a quarter of a million species of plants, trees and animals, from viruses to jaguars.
Brooks documented and studied more than 4000 individuals of parasites, ranging from those that find "shelter" on the bodies of frogs to deer. He identified more than 5000 types of microscopic parasites so he has the largest database in the world. Two-thirds of them are completely new to science.
In his report, the Canadian researcher stated that a lot of work will be required to begin to understand what role the thousands of parasites play in the appearance of diseases, which initially originate in animals and from which they "leap" to humans and cause serious diseases in them. "We still don't know enough about the complex and multi-host life cycles of the parasites and which of them transmit diseases and how, without this necessary information, we will not be able to prevent the appearance of the new diseases that threaten humans," said Dr. Brooks.
While medical science knows quite a lot about the parasite that causes malaria, for example, it knows little about other parasites.
One of the goals of the research is to catalog with modern methods the parasites of the world, using tools from the field of biology and taxonomy (the science of classifying species), molecular and genetics.
Unusual and dangerous weather
At the same prestigious scientific conference, experts presented demands for governments and health and medical officials to "start thinking about appropriate forms of response" to the increasing changes in the world's climate, and to link these changes to health crises such as the appearance of various diseases. The climatic changes that pose health risks are extreme heat waves that can kill people, drought and famine, floods and waves of infectious diseases that follow these events.
Since the world has been undergoing a warming process in recent decades, and since humans are changing landscapes very quickly, it is estimated that many populations will be much more vulnerable to diseases in the future than before: to heat waves that cause death, to air pollution that causes respiratory diseases, to contagious infectious diseases and also to diseases due to malnutrition, which is also caused by natural disasters, which some link to climate change.
Prof. Jonathan Patz, an expert in environmental sciences at the University of Wisconsin, said that severe weather events, the number of which will increase in the coming years, extreme heat waves, huge storms, floods, all of these are caused by changes in the world's climate and are the ones that create the danger to the health of the entire human race.
"Average heat and cold don't kill, extreme situations do," summed up the American scientist's research.
He mentioned the deadly heat wave that hit Europe last year and where between 22 thousand and 35 thousand people died, most of them poor and frail elderly people. "This has so far been an extreme and very unusual climatic event, but it may be an ominous sign of things to come," the American scientist noted.
"We are concerned that such an extreme event will occur frequently. That there will be changes in temperatures in the various regions of the world, that the trends in the change in weather will stop or increase the rains, will cause diseases, will cause the spread of pathogens in the air and then it will be easier for animals to carry pathogens that will infect humans.
For example: strong El Niño events cause torrential rains in the American Southwest, increasing to an alarming extent the population of rodents that are carriers of the severe Ante disease virus when the viruses are spread through the urine of the rodents and their droppings. Humans come into contact with such infections and become infected.
The scientists demand that the weather forecasting and warning systems against unusual weather events be perfected - as part of the preparation for the future. Preliminary estimate: this year, 9 million cases of disease are expected as a result of bacteria and viruses that spread through contaminated water droplets.
