Dangers a warmer planet poses when animals move closer to humans

Climate crisis banner 

Photo credit: SHUTTERSTOCK

What you need to know:

  • Climate change is real and refers to long-term changes in temperatures (global warming) and weather patterns.
  • Some of the weather changes have been evident in many parts of our country in recent years.

Dear doctor,

There has been a lot of talk about global warming and climate change. Is it real? And does it have any impact on our health?



Dear George,

Climate change is real and refers to long-term changes in temperatures (global warming) and weather patterns. Some of the weather changes have been evident in many parts of our country in recent years. The causes and effects of climate change and global warming are complex and have been going on for a long time. However, human activities have partially contributed to it, mainly through the use of fossil fuels e.g. oil, coal and natural gas, especially in industries. The gases produced from the combustion of these fuels “blankets” the atmosphere, so that when the sun’s rays come into the earth’s atmosphere, the heat that is reflected back from the surface is trapped within the atmosphere and cannot be released fully into space. This creates a “greenhouse” effect which leads to a rise in the temperature of the planet. This temperature change then leads to changes in weather patterns.

Medical experts agree that climate change affects health. However, it is challenging to measure which health risks are climate-sensitive, and to what extent. 

Climate change increases the risk of extreme weather events, poor air quality, poor water quality, reduced availability of water, food insecurity, and wildfires. 

It may also lead to changes in disease patterns, like outbreaks of diarrhoeal diseases like cholera when there is flooding; or occurrences of diseases (and their vectors) in places that were previously too cold for them, for instance mosquito-borne illnesses like dengue fever, chikungunya, malaria, among others; or higher incidences of some diseases in the areas where they usually occur. 

Poor air quality may also lead to an increase in respiratory illnesses and poor water quality may lead to diarrhoeal diseases. 

Climate change may also affect the natural environment, leading to movement of wild animals to habitats where they have increased contact with humans, which can lead to new diseases being introduced to the human population. 

All of these illnesses, in addition to the destruction caused by extreme weather events and fires, and food insecurity can have a negative impact on mental health and well-being.

While the issues around climate change are complex and most of the issues outside of our control, we can do our small bit by making environment-friendly choices.

Hello Doc,

What is dengue fever?


Dear reader,

Dengue fever is a disease caused by the dengue virus, and it is spread by mosquitoes. Most people (about 75 per cent) who get infected with the dengue virus do not get any symptoms. 

A few people may develop a mild flu-like disease about three to fourteen days after being bitten and usually the symptoms resolve after a week. The symptoms may include fever, pain in the muscles, joints and bones, eye pain, headache, nausea and vomiting, swollen lymph nodes and a rash. 

Severe disease may develop on rare occasions. Its symptoms include difficulty in breathing, fast breathing, severe abdominal pain, persistent vomiting, and bleeding tendencies like bleeding under the skin, bleeding gums or blood in urine or vomit.  Severe disease may lead to dengue hemorrhagic fever where there is serious bleeding that can lead to shock (very low blood pressure) and death.

There is no cure for dengue fever. For those with symptoms, supportive treatment is provided like fluids and medication for pain and fever. Those with severe disease should be hospitalised for in-patient support. There is a dengue vaccine given to those who have previously been infected.

Prevention of the disease includes protection from mosquito bites through use of mosquito nets and screens, wearing protective clothing and utilising mosquito repellent. There are also environmental measures that can be taken to control the mosquito population, for instance clearing of stagnant water, indoor and outdoor spraying, clearing weeds and filling tree holes.

Septic tanks can also become mosquito breeding areas, which can be prevented by sealing the tank properly, repairing any cracks, and covering the ventilation pipe with screen mesh.

Dear Doc,

There have been cholera outbreaks on and off in the past few years. Is there a way to prevent it?


Dear Millicent,

Cholera is a diarrhoeal disease caused by taking water or food that is infected by the bacteria Vibrio cholera. Most people who get infected with cholera have no symptoms or they develop mild disease. 

Cholera symptoms can begin within a few hours or up to five days after infection. A few of those who get the infection develop severe watery diarrhoea and vomiting, which can very quickly lead to severe dehydration, which if untreated can cause kidney failure, shock (very low blood pressure and death).

When there is severe disease, urgent medical support is required to prevent and treat dehydration. There are also antibiotics that are given to kill the bacteria.

Cholera prevention includes maintaining good hygiene, hand washing, using clean water, proper cooking of meat and seafood; proper cleaning and preparation of fruits and vegetables; and avoiding unpasteurised milk. There is a cholera vaccine available.

Send your questions to [email protected]