Deforestation and Infectious Disease – The Citizen


On July 23 the Director General of the World Health Organization declared the monkeypox virus a global public health emergency in view of increasing cases of the monkeypox disease internationally.

The virus which spreads through close contact including sexual contact has been recorded in 88 countries of the world, with about 28,000 cases confirmed worldwide, according to data released by the US Center for Disease Control and Prevention.

Only 345 cases (1.2%) were found in 7 countries that had historically reported monkeypox. So far the United States of America has recorded the highest number of cases (7,509) in the world. Around the world, eight people are recorded to have died.

Global Spread of Monkeypox Cases on 5 August 2022 (CDC)

According to the WHO, monkeypox is a virus that is transmitted from animals to humans and then from one person to another. Its symptoms are similar to those seen in the past in smallpox patients, but it is clinically less severe than smallpox.

In the early days of this disease, the sufferer has high fever, intense headache, and swelling of the lymphes on the body that fall from face to hands and feet. Along with this, the sufferer may also experience fatigue, backache, palpitations, sore throat, and cough.

The symptoms of this disease usually last for 2 to 4 weeks and then the sufferers get better on their own. In some cases, eye and skin infections can also occur, and in a few cases the disease can be dangerous, even leading to death.

The monkeypox virus was first discovered in 1958 in monkeys used for research in Denmark, but the disease did not originate in monkeys. According to scientists, the main sources of this virus can be squirrels, different types of mice or other small mammals.

In the last 30 years, there have been several outbreaks of the monkeypox virus in African countries, in which many people have been affected by the disease. From 1970 to 2003, cases of monkeypox disease were confined to countries in Africa alone but in 2003, 71 humans contracted monkeypox disease in 6 states of the United States of America. The spread of the monkeypox virus to the United States was traced to animals imported from an African country, Ghana.

The number of diseases spreading from non-human animals to humans is increasing day by day. The host of the pandemic coronavirus is bats, and the host of monkeypox virus are various species of squirrels, rats and other small mammals. If we look at the background, there are many diseases like plague, swine flu, bird flu, malaria, dengue, nipah, ebola, zika, and some others which have been and are transmitted from animals to humans.

There are many reasons for this, such as large-scale deforestation, climate change, human migration, import and export of wild animals, and even the rapidly growing trend of owning more pets.

It is a well established fact that deforestation can be a strong driver of infectious disease transmission. A 2019 research study by Katrina Zimmer shows a direct link between deforestation and malaria in Brazil. The study finds that a 10% increase in the extent of deforestation per year from 2003 to 2015 has led to a 3% increase in cases of malaria.

Similarly, in Sabah, Malaysia, malaria outbreaks occur due to clearing of forests for palm and other plantations. Clearing forests for palm cultivation (commercial farming) in Liberia too has spread the Lassa virus among humans, when they come into contact with food or objects contaminated with feces or urine of virus-carrying rodents from forest. This virus spreads the same kind of disease caused by the Ebola virus among humans. In Liberia, 36% of people infected with the Lassa virus died.

Similarly, the mosquito that spreads the Zika virus is found in the forests of Uganda and could sicken millions of people. This virus spreads rapidly in cities. The more we degrade and clear its forest habitats, the more likely it is that we will find ourselves in situations where epidemics or pandemics of infectious diseases occur.

This is because almost all the countries of the world are clearing forests at a very fast rate for corporate development and commercial agriculture. According to a 2020 report by the Food and Agricultural Organization of the United Nations, 178 million hectares of forests have been killed in the last three decades, in the last five years at the rate of 10 million hectares per year.

Wild animals are also being displaced on a large scale due to rapid deforestation. The animals displaced from the forests come closer to the human population along with their diseases and viruses. This puts humans at high risk of being exposed to the diseases of wild animals. Sometimes, due to lack of proper medicine, these diseases spread from local to national and international levels.

Scientists have been warning for a long time that with the increase in the average temperature of the earth, the diseases that occur in tropical countries, which are carried by mosquitoes, and bats found in forests, can spread rapidly in countries that have had colder temperatures so far. According to a research study (2021) published in The Lancet Planetary Health Journal, by 2080 nearly 90% of the world’s population could be infected with malaria and dengue fevers.

According to the United States Agency for International Development, there is a possibility that 75 per cent of the diseases affecting the human population in the 21st century would be related to animals. Carson and his fellow researchers find that there are at least 10,000 viruses in wild animals that have the ability to infect humans, but at present are circulating silently in wild animals. Since human activities including land use are directly affecting the climate, in coming times we will be at higher risk of coming into contact with these viruses.

With the increase in the average temperature of the earth, the animals of the hot regions have started moving towards regions where they can find the temperature according to their physiological needs. With the migration of animals, they go to other areas with their diseases and viruses, but the people of those areas are not able to bear the new diseases and viruses. So these new diseases and viruses can prove to be very fatal for them.

During the import or export of animals, treating them as objects, the parasites and viruses that live on animals also move with them to other places and spread disease there. Another unique trend emerging these days is that of domesticating dogs and cats. Many households have more than one dog and one cat. Animal diseases and viruses are different and some can prove fatal to humans. Animal borne diseases can spread widely.

Technological development meanwhile has led to amazing advancements in the means of transportation. Now we can travel distances earlier completed in days and months in hours and days by airplanes. Earlier the means of transportation were not so developed. Therefore, any disease that occurred in a particular area would stay localized and disappear within a few months or days, but now it spreads rapidly from place to place.

Instead of killing forests, we should protect, restore and grow them to avoid displacing animals. By increasing the area under forests, wild animals should be provided with safe habitats. In order to control the increase in the average temperature of the earth, besides increasing the area under forests, public transport facilities should be provided to reduce the number of private vehicles. Electricity should be generated from wind, water, and the sun instead of coal and oil.

These recent public health emergencies are trying to alert us to take action as soon as possible else the future might hold frequent or worse occurrences of such cases.

Dr Gurinder Kaur is Former Professor, Department of Geography, Punjabi University, Patiala

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