The diseases spread by climate change

Global warming and extreme weather events cause an increased spread of epidemics. An Israeli researcher warns of dangerous diseases that may reach our region in the near future and of those that are already here

By Maya Falah, Angle, Science and Environment News Agency

Outbreaks of epidemics and mass diseases that destroy most of the earth's population often sound like material for futuristic-fiction series or interest for a historical drama. In the 14th to 17th centuries, for example, the bubonic plague raged in Europe - it was called the Black Plague, and it is estimated that it killed about 50 percent of the continent's population at that time. However, since the invention of penicillin in the 19th century and with the development of modern medicine - which succeeded in developing vaccines for so many diseases, increasing by hundreds of percent the number of babies who survive the first year of their lives and increasing life expectancy - it is difficult to imagine a scenario in which the entire population of the earth would be affected by a disease or epidemic that today's medicine will not be able to prevent its spread.

Is this really how things are, or is this a naive belief in the power of modern medicine? In recent years, viruses and diseases appear from time to time that spread quickly and cause mass panic in the global community: the Sars that stressed us in the early 2000s, the swine flu that scared us about a decade ago, the Ebola that made us tremble about three years ago, and in the last year we also learned about the Zika that causes panic in the world public, and throughout The Americas are mainly preparing for the possibility of Her outbreak this summer.

The fear is that the effects of climate change, which have plagued us more and more in recent years, and which, according to all predictions, will only intensify over the next decades, greatly help the spread of these diseases and weaken our ability to deal with them. This is mainly because hot temperatures are a breeding ground for the spread of bacteria, viruses, carriers and transmitters of various diseases, but also because extreme events such as heat and cold waves, droughts, storms and floods that are expected to hit us more and more in the coming years will make it difficult for the health system - even in western and medically advanced countries - to function under the load of patients, especially if such events are accompanied by the collapse of infrastructures that will shut down the hospitals.

Dengue in the Mediterranean

Last year the White House issued Report of the American Global Change Research Program which warns of the expected effects of climate change on human health. Among other things, the report warns of diseases related to the decline in air quality, vulnerabilities from extreme events such as storms, droughts and floods, contamination of our drinking water with sewage, various chemicals, as well as diseases that are transmitted through drinking water, such as cholera, for example, as well as diseases transmitted by carriers - such as fever West Nile, malaria, dengue fever and as of the last year or two - also the Zika virus.

Diseases that are transmitted by a carrier, usually in the form of a mosquito or tick, are often carried by creatures that feed on blood. They pass from one animal to another between meals, and may also transmit diseases between them. In this way, some diseases also pass from animals to humans. Zika is a disease that is currently transmitted by the Egyptian Hades mosquito, which does not exist in Israel. The mosquito is also responsible for the transmission of dengue fever and yellow fever, and is a relative of the Asian tiger mosquito - which arrived in recent years and is considered an invasive species in Israel. The fear today is that because these carriers thrive in warm temperatures and near bodies of water, climate change is going to make our world a breeding ground for outbreaks of these diseases.

"Different studies from around the world point to a clear connection between the increase in temperature as a result of climate change and the spread of diseases that are transmitted by mosquitoes," says Prof. Shlomit Paz, head of the Department of Geography and Environmental Studies at the University of Haifa, "such diseases are also reaching areas where they were not before . We saw one of the main examples of this in a project of the European Center for Disease Control (ECDC) that I chaired, in which we investigated the causes of the spread of West Nile fever in Europe: in recent years, the virus appears in areas where it was not previously, for example, in Southern Europe and the East - and is established in them, that is, the disease appears in the area every year after undergoing a process of endemization (adaptation to the area). A severe heat wave encourages the outbreak of the disease in the area, and then it is there to stay.'

"Today there are outbreaks of diseases transmitted by mosquitoes in new areas, which become suitable for this in terms of their climate conditions," says Paz. "For example dengue fever: every year in Europe there are cases of dengue that are imported - meaning they arrive in the area with tourists - but in recent years there have been several local outbreaks of dengue - mainly in the northern Mediterranean basin - and today there is a fear that it will appear in southern Europe. Today the conditions in Europe are still not suitable for this, but according to health officials in Europe there is a great fear that in the warm parts of the continent - such as southern Europe and the northern Mediterranean - there will be an outbreak of the disease in the coming years.

"It is true that these are diseases that are affected by many different factors," she adds, "and we do not claim that climate change is the only factor. But it is a factor that has a very, very great significance, and we have been able to show in several studies and works that temperature is the environmental factor that has the most significance on the outbreak of these diseases and their spread. Also regarding the Zika disease, which broke out last year in South America, we showed the connection between the high temperatures and other climate conditions for its outbreak.'

No standing water

Even in Israel, a warm country whose climate is suitable for mosquitoes, there seems to be reason for concern. "From studies we have conducted in recent years, we see an increase in West Nile fever in Israel following heat waves," Paz says, "there is an increase in the distribution of mosquitoes following heat waves, sometimes, such as occur in early spring. This means that a heat wave in March is enough - something that has been happening in recent years - and then there is an increase in outbreaks of diseases transmitted by mosquitoes, such as West Nile fever. Accordingly, in recent years we have seen an appearance of the disease in earlier seasons. The appearance of West Nile fever, for example, used to be limited mainly to August and September, but today it appears already in the spring, and stays right until the end of autumn.'

So what can we do? To defend against mosquitoes, recommend in the Ministry of Environmental Protection וat the Ministry of Health When staying outside in the evening, apply mosquito repellent preparations on all parts of the body and try to wear light long clothing; In the area of ​​the house, they recommend installing mosquito repellent devices and making sure to use them according to the instructions, installing dense nets on the windows to prevent mosquitoes from entering and making sure to close the house doors during the hours of darkness, and they also recommend using fans or air conditioners during these hours.

"In addition, it is important to pay attention to reducing the standing water sources around us," says Paz. "We are not a country steeped in lakes, but it is enough to have a pot in the yard that we watered and there is water left at its base, a pitcher with leftover water in the garden or a discarded tire that has stagnant water on the inside, so that the mosquitoes can breed in it. The Ministry of Environmental Protection sprays against mosquitoes, but the spraying has environmental problems. Today there is no vaccine for most of these diseases - including West Nile fever - so it is important to be vigilant and pay attention not to leave stagnant water sources around.'