Mosquitoes are a big part of the ecosystem, but often are a nuisance as they bite and feed off of us. Their bites cause itchy red bumps and spread infections and allergies in our bodies. But have you ever wondered why they bite certain people more than others? While some people are plagued by mosquito bites, others barely notice them. Here are some interesting facts about mosquitoes that you must know about!

1. Carbon Dioxide:

Mosquitoes are attracted to a certain smell that emits from the human body that is present in the human skin and sweat, mosquitoes can sense the carbon dioxide or CO2 we breathe out. The more active you are, the more CO2 you emit and the more mosquitoes will be attracted to you. Researchers are still investigating the cause of the variation of body odour that brings them to you, possibly genetics or certain bacteria. The unique combination of sweat and skin bacteria creates a scent that mosquitoes find irresistible. Some chemicals in sweat, like lactic acid and ammonia, are especially attractive to them.

2. Colours

While the reason isn't fully understood, mosquitoes seem to be drawn to dark colours like black more than lighter ones. So, ditch the dark outfit next time you're in mosquito territory. It has been noted that mosquitoes are more likely to leave lighter colours alone.

3. Heat and Vapour

Mosquitoes can detect your body's heat and water vapour, acting like a beacon guiding them right to you. So next time you're feeling sweaty, be aware you might be attracting a lot of mosquitoes. If you are working out or doing something that is making you sweat and your body heat rise, the mosquitoes nearby will be instantly attracted to you. Even mosquitoes are careful about who they pick as a host, some studies even suggest that they like a certain body temperature to feed off of.

An interesting fact about mosquitoes is that they can learn to like a host. They have their own preferences and if they meet a certain person who fits their criteria they might be the next host they move onto. In an older study, it showed that 20 per cent of people with mosquito-borne diseases accounted for 80 per cent of diseases transmitted in the population. They suggest that they only bite a certain set of people within the population.

4. Other factors:

Studies suggest mosquitoes might learn to prefer certain people based on things like what you've been drinking. In a 2002 study, there could be many reasons they like alcohol to making your body temperature high etc. Even pregnant women seem to be extra attractive to them due to higher body temperature and CO2 output.

Delhi's Air Quality Index today recorded 'severe' in several location. The Central Pollution Control Board (CPCB) data from 40 monitoring stations from across the city showed AQI above 401 at 7.05 am on Wednesday morning. City's average AQI stood at 376.

While it has only been three days into December, the AQI levels have undergone severe changes. On November 30, Delhi's AQI was recorded at 279, on December 1, it was recorded at 304, while on December 2, the AQI went up to 372.

Amid all this, Dr Ritu Singh, Director Professor and HOD, Department of Biochemistry at Lady Hardinge Medical College posted on her Instagram, what she calls the 'only steps to save your lungs in Delhi".

What Does the Doctor Say?

"If you’re living in Delhi right now, the first line of protection is simple: avoid breathing unfiltered air. If you can’t leave the city, wear an N95 mask every time you step outside or move away from a HEPA-filtered space," says Dr Ritu Singh.

The doctor points out that keeping a high quality HEPA filter at home and at your workplace is essential. She points out that though it may be expensive, but one should know that their "lungs are not replaceable". She says, "Yes, spend all your hard earned money on HEPA filters because the lung is not replaceable."

What Is HEPA Filter? How Does It Help?

As per the US Environmental Protection Agency (EPA), HEPA or also known as the high efficiency particulate air is a type of filter that can theoretically remove at least 99.97% of dust, pollen, mold, bacteria, and any airborne particles with a size of 0.3 microns (µm). The diameter specification of 0.3 microns corresponds to the worst case; the most penetrating particle size (MPPS). Particles that are larger or smaller are trapped with even higher efficiency. Using the worst case particle size results in the worst case efficiency rating (i.e. 99.97% or better for all particle sizes).

What Else Can Be Done To Stay Safe From Air Pollution?

Dr Singh suggests that indoor plants could be added, though it could only offer a "small but meaningful improvement in air quality".

One famous NASA experiment, published in 1989, found that indoor plants can scrub the air of cancer-causing volatile organic compounds like formaldehyde and benzene.

These plants are:

• Spider Plant
• Snake Plant
• Peace Lilly
• Aloe Vera
• Boston Fern
• English Ivy
• Rubber Plant
• Golden Photos
• Bamboo Palm
• Dracaena

The doctor also recommends that one should increase their intakes of antioxidant foods. "Increase your antioxidant intake—turmeric, amla, oranges—these won’t fix pollution, but they help your body cope with oxidative stress.”

Antioxidants strengthen the immune system by fighting oxidative stress, which is caused by unstable molecules called reactive oxygen species (ROS). The body's normal processes, like breathing and metabolism, create free radicals (ROS). Antioxidants donate electrons to these unstable molecules, which neutralizes them and stops them from damaging healthy cells.

"Right now, the goal is extremely clear: prevent inhalation of polluted air. Delhi’s current levels are dangerous for the lungs, the heart, and the entire respiratory system," the doctor says.

India is only second in the world to have people with chronic kidney diseases in 2023, said The Lancet study. In 2023, China recorded 152 million patients with chronic kidney disease (CKD), while India was at 138 million.

The study, led by researchers from the Institute for Health Metrics and Evaluation (IHME) at the University of Washington, along with collaborators in the U.S. and the U.K., found that CKD was the ninth-leading cause of death worldwide, claiming nearly 15 lakh lives in 2023.

Regionally, the highest prevalence was reported in North Africa and the Middle East (18% each), followed by South Asia (nearly 16%), and more than 15% in Sub-Saharan Africa, Latin America, and the Caribbean.

In fact, senior director and HOD Nephrology at Medanta Kidney and Urology Institute, Dr Shyam Bansal says, "Chronic kidney disease is one of the fastest-growing chronic illnesses in India, mainly because diabetes and hypertension are becoming more common. Diabetes now affects about 10% of the population and hypertension nearly 25%, and together they remain the leading causes of kidney disease."

The report also highlighted CKD’s strong link to heart disease. It contributed to almost 12% of global cardiovascular deaths in 2023 and ranked as the seventh-leading cause of heart-related mortality, ahead of diabetes and obesity.

The researchers outlined 14 key risk factors for CKD, with diabetes, hypertension, and obesity contributing the most to the loss of healthy life. Dietary habits—such as low intake of fruits and vegetables and high sodium consumption, also played a significant role in raising CKD risk.

“Chronic kidney disease is both a major risk factor for other leading causes of health loss and a significant disease burden in its own right. Yet, it continues to receive far less policy attention than other non-communicable diseases, even as its impact grows fastest in regions already facing the greatest health inequities,” said senior author Theo Vos, professor emeritus at IHME.

The findings draw on data from the Global Burden of Disease (GBD) 2023 study, which tracked trends in diseases, injuries, and health risk factors across 204 countries and territories from 1990 to 2023.

Importance of Early Detection Of Chronic Kidney Disease

Importantly, the authors noted that most people with CKD in 2023 were in the early stages, highlighting the urgent need for strong screening programmes and strategies to reduce risk before the disease advances.

This is why its early diagnosis is utmost important. Dr Bansal on the need for early detection says, "“The biggest challenge is identifying people at risk as early as possible. Early diagnosis and timely control of risk factors are essential if we want to slow the progression of chronic kidney disease."

Early detection could also reduce heart-related deaths due to kidney disease and delay one's requirement for replacement therapies, which is usually sought in advanced stages of the disease.

Dr Bansal also points out that early detection could help one live a better life and also in many ways reduce the burden on the Indian healthcare system, and save cost. "We are dealing with a large population at risk, and kidney disease is complex and costly to treat. While infrastructure and specialist availability are improving, managing this growing burden remains a significant challenge," he says.

A GP has raised concern about a key sign that may show you have Covid rather than a cold or flu. Winter illnesses often look alike, which makes it hard to tell them apart, and getting the right diagnosis is important for proper care. Dr Rupa Parmar, GP and medical director at Midland Health, explained that there are certain clues that can help people understand what they are dealing with. She advised that anyone unsure should check with their doctor, as it is safer to ask than ignore a concern.

Why Breathlessness Matters

Dr Parmar noted that shortness of breath stands out as a sign of Covid. It rarely appears in a cold or flu, but it is common with Covid because the infection tends to affect the lungs and cause inflammation. The NHS also lists breathlessness as a sign linked more strongly with Covid than with flu or a cold. This symptom is also seen in conditions such as respiratory syncytial virus. In some cases, people with the flu who do not recover and worsen may develop breathing trouble if they develop complications such as pneumonia.

How Cough Patterns Differ

She added that coughs appear in all three infections, but they do not sound the same. A cold usually causes a light cough, flu tends to bring a dry one, and Covid usually causes a dry, ongoing cough. Many people with Covid cough for more than an hour or have several episodes of coughing through the day.

Loss Of Taste Or Smell As A Warning Sign

Another clue is a change in taste or smell. Dr Parmar said this sign is more specific to Covid. A sudden loss of taste or smell, or even a noticeable change, is more likely linked to the coronavirus. She explained that the pattern of symptoms often helps point to the right illness. A mild cough and sore throat usually fit a cold, a fever and strong fatigue suggest flu, and a loss of smell or taste with a steady cough point to Covid.

How Symptoms Begin And Progress

She also noted that the start of symptoms can differ. A cold tends to appear slowly, flu symptoms usually show up quickly within a few hours, and Covid can begin with mild signs that grow stronger over time. A cold mainly affects the nose and throat, while flu and Covid can cause symptoms across the body.

What To Do If You Have Covid Symptoms

Even though there are no formal self-isolation rules anymore, the NHS advises people to stay home and limit contact with others if they or their children have symptoms and either have a high temperature or feel too unwell to manage daily activities at work, school, or home. The NHS states that people can return to their usual routine once they feel well again or no longer have a high temperature.