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-NCR witnessed unexpected showers in the city this year in the month of April. Before the heatwave could get as severe as it usually is every season, there were a few days where the national capital witnessed refreshing showers—but as it turns out, these showers often increase the risk of diseases like malaria. Yes, unexpected showers may bring temporary relief from heat, but they also quietly reset the risk for diseases like malaria. The concern today is not just rainfall, but how changing climate patterns are shifting the timeline of disease transmission—often weeks before the monsoon fully arrives.

Ahead of World Malaria Day, Dr Suranjit Chatterjee, Senior Consultant-Internal Medicine, Indraprastha Apollo Hospital, Delhi, spoke about the effects of such unexpected rains ahead of the monsoon season.

Has the malaria pattern changed?

Malaria has long been seen as a monsoon-linked illness, but that pattern is changing. Intermittent rainfall, rising temperatures, and increased humidity are now creating ideal breeding conditions much earlier in the year. Even a short spell of rain can lead to water accumulation in urban areas—on terraces, construction sites, in clogged drains, and in poorly managed storage spaces. These become hidden breeding grounds for mosquitoes, accelerating their life cycle and increasing the risk of early transmission.

When should you get tested for malaria?

From a healthcare perspective, this shift is significant. The first fever after early showers is often overlooked or dismissed as a seasonal viral infection. However, malaria in its early stage can closely resemble common viral illnesses, presenting with symptoms such as fever, chills, headache, body ache, and fatigue. This overlap frequently delays diagnosis. Any fever that persists beyond 2–3 days, recurs, or does not respond to basic treatment should be tested promptly. Early detection remains critical to preventing complications.

What are the symptoms of malaria?

Early malaria can look like a common viral fever. The symptoms of the disease are:

1. Body aches
2. Fever
3. Chills
4. Weakness
5. Headaches

Malaria prevention matters

Waiting for the monsoon to begin preventive action is no longer effective. The response must start with the first signs of rain. Clearing drains, eliminating stagnant water, monitoring construction zones, and ensuring proper waste management are essential early steps. At the household level, covering water containers, maintaining clean terraces, and regular checks for water accumulation can significantly reduce risk. Some of the key precautions to take against malaria are the following:

1. Use a mosquito repellent before going outdoors
2. Wear long sleeves and light coloured clothes
3. Use bed nets
4. Avoid keeping the windows open, especially in the evening
5. Standing water are breeding ground for malaria; avoid water sit in coolers or pots for too long

A year-round public health priority

World Malaria Day serves as a reminder that malaria prevention is not seasonal—it is continuous. In an era of unpredictable weather patterns, cities and communities must adapt quickly. Acting only when cases begin to rise means reacting too late. The real shift lies in recognising that prevention must begin with the first unexpected shower, not the peak of the monsoon.

Urgent action is required to strengthen diagnostics and vaccines to address gaps in dengue treatment, public health experts said.

The experts, including scientists and policymakers, were speaking at a day-long dialogue hosted in New Delhi by the Drugs for Neglected Diseases initiative (DNDi) in collaboration with the Translational Health Science and Technology Institute (THSTI), the Ministry of Health and Family Welfare, and the WHO South-East Asia Region.

The convening assumes significance ahead of the monsoon season, which historically sees a rise in Aedes aegypti mosquito populations and dengue transmission across health systems in South and South-East Asia.

"The WHO South-East Asia Region alone accounts for more than half of the global dengue burden, with 1.3 billion people living at risk across 10 endemic countries," said Dr Catharina Boehme, Officer in charge, World Health Organization, South-East Asia Regional Office.

Dr. Boehme called the rising burden of dengue both an economic crisis and a social crisis. She noted that beyond health system costs, dengue often leads to "lost productivity, lost wages, lost futures".

"To change this trajectory, we must close the gap on diagnostics, on vaccines, on therapeutics, and on health system resilience," Dr. Boehme said.

Also read: New dengue vaccine over 80% effective, prevents severe disease for up to 5 years

India Advancing in Dengue Fight, Gaps Remain

India reported over 2.89 lakh dengue cases in 2023, though experts believe the actual burden could be significantly higher due to underreporting and surveillance gaps.

Taruna Madan Gupta, Scientist G and Head, Development Research Division, ICMR, called dengue an "unequivocally a national health priority for India."

Gupta noted that "India is advancing on multiple fronts—from strengthening public health systems to enabling public-private partnerships, including Phase III trials of an indigenous tetravalent dengue vaccine with over 10,000 participants, and regulatory progress on global vaccines".

However, the expert flagged a critical gap, which is "the absence of an effective therapeutic" for the mosquito-borne disease.

The experts noted that even though there are improvements in surveillance and scientific understanding, patients still lack access to specific treatment options.

“Addressing this gap requires sustained commitment from governments, funders, and partners," said Dr Sanjay Sarin, Continental Lead Asia and Director South Asia, DNDi.

What Is Dengue?

Dengue fever is a viral disease transmitted by Aedes mosquitoes, which are most active during the daytime. Dengue fever typically has minor or no symptoms, but it can occasionally result in severe sickness, hospitalization, and even death.

Common Symptoms include:

• Sudden onset of high-grade fever.
• Intense headache
• Severe muscle, joint, or bone pain.
• Skin Rash that often appears 2–5 days after the fever starts
• Nausea and Vomiting
• Fatigue

It estimates that:

• About 390 million dengue infections occur annually worldwide
• Nearly 100 million people develop symptoms each year

These vaccines are designed to protect against all four serotypes of the virus, with a focus on reducing severe disease and hospitalizations.

In today’s fast-paced, wellness-driven world, looking fit does not always translate to being reproductively healthy. Currently, even fit and active individuals are facing fertility challenges due to hidden hormonal and metabolic imbalances. Hence, it is necessary to focus on reproductive health. Dr. Meenu Handa, Director of Fertility & Head Academic of Reproductive Medicine, Motherhood Hospitals, Gurgaon, decoded the link and listed some of the common fertility issues that most people overlook.

Now, a large number of people are opting for various activities such as yoga, Zumba, Pilates, the gym, and kickboxing to stay fit. Those who are health-conscious are also maintaining an optimum weight with a proper diet. These habits, in turn, can help to ensure good fertility. Shockingly, many people who are perfectly fit and fine on the outside may also struggle with fertility problems. Yes, that is right! This is also a common occurrence nowadays. Couples are panicking as they seem to adhere to a well-balanced lifestyle but still fail to conceive. So, this can be referred to as “invisible fertility issues," where underlying hormonal or metabolic imbalances silently affect reproductive health.

Decoding invisible fertility issues

Dr Handa said that many men and women who exercise regularly may suffer from issues such as hormone imbalance, fluctuating insulin levels, poor thyroid function, and compromised reproductive organ health. Conditions like polycystic ovary syndrome (PCOS), thyroid disorders, insulin resistance, and even chronic stress can exist without obvious physical signs and can take a toll on fertility. The expert also shared some of the common hidden infertility issues.

Even couples who are physically fit today often deal with high mental stress due to demanding jobs and poor work-life balance. This ongoing stress can quietly disturb hormonal balance in the body. Increased cortisol levels may affect ovulation in women and sperm production in men and, over time, can impact egg and sperm quality—making natural conception more difficult. That is why managing stress is just as important as staying physically fit when planning a pregnancy.

Women may have issues like poor ovulation, compromised egg quality, or hormonal imbalance, even if their menses tend to be regular. In some cases, even subtle symptoms like fatigue, acne, hair fall, or mood swings may be overlooked but can signal deeper hormonal concerns. Men can struggle with low sperm count, which can affect their fertility. Even insufficient sleep, excessive exercise, or extreme dieting can increase the chances of hormonal imbalance and fertility issues. It is necessary to consult an expert and seek timely help. Pollution and lifestyle stress also contribute to the trend.

Couples should not just plan a pregnancy because they are fit and exercise daily. Pregnancy should not rely only on outward fitness as a sign of reproductive health. Regular health check-ups, including hormone tests and fertility assessments, can help identify hidden issues early.

Follow these tips

1. Couples should eat a well-balanced diet, exercise daily, stay stress-free by practicing yoga and meditation, and get enough rest.
2. It is also imperative to maintain blood pressure and blood sugar levels within the recommended range, include healthy fats and proteins in the diet, avoid overtraining, and manage stress through relaxation techniques like yoga or meditation, which can support hormonal balance.
3. If a couple is unable to conceive even after 6–12 months of trying (depending on age), a detailed fertility evaluation is recommended.
4. Seeking timely medical advice is equally important if conception is delayed.
5. Couples who find it challenging to conceive may be advised to use ARTs, such as in vitro fertilisation (IVF).

So, awareness, balanced lifestyle choices, and timely medical support can make a huge difference in improving fertility outcomes.