Top 12 Most Common Illnesses During Hot Weather

Cholera in humans (Cholerae) is an acute infectious disease that affects the digestive system. The main symptoms of cholera include severe vomiting and diarrhea, which can lead to severe dehydration and electrolyte imbalance, resulting in shock. Without prompt treatment, it can be fatal. Cholera caused major pandemics in the past, claiming millions of lives. While cholera is now controlled in many regions, outbreaks still occur in parts of Africa and some Asian countries. In Vietnam, cholera is still present, though mostly sporadic, typically in coastal provinces during the summer.

Cholera is caused by the Vibrio cholerae bacteria, transmitted through contaminated food or water. The hallmark symptom is sudden and profuse diarrhea, resembling cloudy rice water, often accompanied by vomiting and severe dehydration, which can be life-threatening. If cholera symptoms appear, seeking medical care immediately is crucial. The best preventive measure is to eat thoroughly cooked food and drink clean water.

Dysentery, also known as bacillary dysentery, is a serious intestinal infection that causes severe diarrhea, which may include blood. In some cases, mucus can also be found in the stool, with symptoms lasting from 3 to 7 days. Dysentery is often spread through poor hygiene. For example, if someone with dysentery fails to wash their hands after using the toilet, anything they touch may become contaminated. The infection can also spread through contaminated food or water. Proper handwashing and hygiene practices can help prevent dysentery and stop its spread.

According to epidemiological data, the number of dysentery cases increases during hot weather, especially on extremely hot days. Those affected usually ingest contaminated water or food infected with the dysentery bacteria, which thrive in hot temperatures. Typical symptoms include acute diarrhea with blood and mucus, abdominal cramps, and fever. To prevent dysentery, it is important to eat thoroughly cooked food, drink boiled water, and ensure proper hygiene during food preparation.

Heatstroke is a severe heat-related illness. Normally, the body maintains a balanced temperature despite environmental changes, but prolonged exposure to extreme heat or strenuous activity can disrupt this balance. When the body's thermoregulatory system is damaged or overwhelmed, the body temperature rises rapidly, leading to dysfunction in bodily systems, especially the nervous system, which may result in unconsciousness or even death. Humans, as warm-blooded animals, have a body temperature that stays relatively constant around 37°C, an evolutionary survival advantage.

However, extreme heat can overwhelm the body’s defenses, or a sudden shift from a cool environment to a hot one (such as moving from an air-conditioned room to the outdoors) can trigger heatstroke. Symptoms include fatigue, difficulty breathing, chest tightness, dizziness, low blood pressure, and fainting. To prevent heatstroke, ensure living and working spaces are well-ventilated, wear hats, face masks, and sunglasses when outdoors, and avoid sudden transitions from cool to hot environments.

Mental disorders refer to a condition that affects an individual's thoughts, emotions, and behavior. This condition is closely related to difficulties in social, work, and family activities. Mental disorders can be classified into various types. According to the World Health Organization's International Classification of Mental and Behavioral Disorders, there are over 300 different types of mental disorders, such as schizophrenia, alcohol or drug-induced mental disorders, dementia, post-traumatic brain injury or encephalitis, delusional disorders, mood disorders, bipolar disorder, anxiety disorders, excessive sleepiness, insomnia, sleepwalking, nightmares, and more.

Recent statistics from the Central Institute of Mental Health show that some mental disorders, such as schizophrenia, acute psychosis, and reactions to acute stress, tend to increase during hot weather. High temperatures can physically affect the nervous system, keeping the brain in a constant state of stimulation and agitation, which may lead to mental health issues. To prevent such conditions, it is important to maintain a balanced work and rest schedule, and ensure that living and working environments are well-ventilated and spacious, which can help reduce the occurrence of mental health problems.

Dengue Fever is an infectious disease caused by the Dengue virus. There are four types of Dengue virus: DEN - 1, DEN - 2, DEN - 3, and DEN - 4. The virus is transmitted from infected individuals to healthy ones through mosquito bites. Aedes mosquitoes, particularly Aedes aegypti, are the primary carriers of the disease. Dengue fever occurs year-round, with an increase in cases during the rainy season. Both children and adults can contract it. The main symptoms of Dengue fever include high fever, bleeding, and plasma leakage, which can lead to shock, clotting disorders, organ failure, and, if not diagnosed and treated promptly, may be fatal.

Rising temperatures create ideal conditions for the breeding of mosquitoes and the spread of the Dengue virus. Dengue fever presents with a range of symptoms and can progress rapidly from mild to severe. The disease typically starts suddenly and progresses through three phases: the fever phase, the critical phase, and the recovery phase. It is especially dangerous as there is no specific treatment available. Therefore, prevention is crucial. We must actively eliminate mosquito breeding sites, destroy larvae, and sleep under mosquito nets, even during the day, to protect ourselves.

Epilepsy is a disorder of the central nervous system (CNS) in which brain activity becomes abnormal, leading to seizures or unusual behavior, sensations, and sometimes brief periods of unconsciousness. Though death-causing complications of epilepsy are rare, they can occur due to a seizure-induced loss of body control, resulting in unpredictable consequences, including permanent brain damage or death from cardiac or respiratory complications.

Like mental health disorders, high temperatures are one of the factors that stimulate the nervous system, making it easier for epilepsy seizures to occur in people with sensitive constitutions or weakened immune systems. To reduce seizure frequency, patients should take their medication regularly, maintain a balanced schedule for study, work, and rest, and avoid working in excessively hot environments.

A cerebrovascular accident (stroke) occurs when the brain suddenly experiences a lack of blood flow, either in part or entirely. This results in weakness or paralysis in the body parts controlled by the affected brain regions, and in some cases, even coma. A severe consequence of this condition can be death. The two terms describe the phenomenon, with stroke referring to the acute onset of the condition, and cerebrovascular accident indicating the location of the issue. According to recorded data, stroke is the second leading cause of death (20%) and is also associated with an increased risk of dementia.

According to statistics from the Vietnam Cardiovascular Society, in recent years, the incidence of diseases such as brain hemorrhage, hypertension, subarachnoid hemorrhage, and strokes has been rising due to increasingly hot weather. This is because the autonomic nervous system is triggered by high temperatures, leading to a series of harmful effects on the body, including cerebrovascular and cardiovascular conditions. Preventative measures include taking prescribed medications, strengthening the body's resilience to heat, staying hydrated, and avoiding work in excessively hot environments.

Rubella, also known as German measles, is a contagious viral infection caused by the rubella virus. It is a viral illness that can spread rapidly, particularly in crowded places such as schools, dormitories, companies, and factories. The disease is transmitted through droplets in the air from sneezing or coughing or direct contact with an infected individual. While most cases are mild, rubella can cause severe complications in pregnant women, including miscarriage, stillbirth, or birth defects in the fetus.

The rubella virus, which contains RNA and belongs to the togavirus family, typically thrives in the spring and summer. It spreads through respiratory droplets, with the virus residing in the throat and lymph nodes. Direct contact with mucus from the nose or throat or droplets from coughing or sneezing can lead to infection. The most contagious period for rubella is from 7 days before to 7 days after the appearance of the rash. Anyone who has not developed immunity to rubella is at risk of contracting the virus, as there are no known cases of healthy carriers of the virus.

Hypertension is a silent condition that develops over many years, often worsening during hot weather. It is commonly discovered incidentally or only when complications arise. If untreated, hypertension can lead to severe consequences such as heart attacks, strokes, and kidney failure. There are two types of hypertension: primary (essential) and secondary (caused by other conditions). Primary hypertension, which is the most common form, accounts for 90% of cases and often has no identifiable cause.

A hypertensive crisis occurs when blood pressure suddenly spikes above 180/120mmHg. These crises are divided into two categories: emergency and urgent. An emergency hypertensive crisis is characterized by blood pressure above 180/120mmHg along with evidence of organ damage (such as hypertensive encephalopathy, retinal damage, acute kidney failure, heart attack, or aortic dissection). An urgent hypertensive crisis has no organ damage. Both types require immediate medical intervention and treatment.

When working or spending too much time outdoors in the sun, intense rays directly hit the neck and shoulders. Continuous exposure to harsh sunlight disrupts the body's temperature regulation center, causing dehydration and a heat imbalance. As a result, heatstroke often manifests as a severe condition right from the start, with early neurological signs that may or may not recover. In some cases, there could be bleeding beneath the dura mater or inside the brain.

The hallmark of heatstroke is an elevated body temperature. As the body’s temperature rises, excessive sweating leads to significant fluid loss. If not replenished quickly, this may cause a drop in circulatory volume, leading to cardiovascular collapse, severe electrolyte imbalances, and even death. Another danger arises when the body's temperature spikes, disrupting the function of several organs, including the heart, lungs, and nervous system. Symptoms of heatstroke can vary depending on the severity of the temperature rise and the duration of exposure. They may start with mild signs such as rapid heartbeat, shortness of breath, palpitations, followed by fatigue, dizziness, headaches, weakness, irritability, worsening shortness of breath, cramps, and eventually leading to fainting, coma, cardiovascular collapse, and even death.

The skin consists of multiple layers, much like an onion. The deeper the infection penetrates, the more dangerous it becomes. The first layer is the epidermis, responsible for producing skin cells and determining skin color. The second layer, the dermis, produces oil to protect the skin and sweat to cool it down. This layer also contains nerve endings that sense heat, cold, and pain. The third layer is the subcutaneous fat, which connects the skin to muscles and bones, helping regulate body temperature.

The skin is home to various types of bacteria, which thrive in hot conditions. When the weather is warm, the skin becomes thinner due to excessive sweating and oil production, weakening its defense against bacteria and viruses. This allows them to penetrate the skin, causing conditions such as allergic dermatitis, rashes, pustular infections, scabies, boils, and herpes. When suffering from skin infection, it's important not to self-medicate. Instead, visit a dermatologist for proper diagnosis and treatment. Avoid applying medication to the inflamed area as it could worsen the condition.

Hot and humid weather creates the perfect conditions for harmful bacteria, especially those in the digestive system, to multiply and thrive. Meanwhile, many people have habits of improperly handling or cooking food, or storing it incorrectly, leaving it in hot air for too long. If food isn't cooked thoroughly enough to kill bacteria, this allows the bacteria to proliferate and spoil the food.

In many places with difficult living conditions, people still have to cook with water sources that are not sanitary or prepare food in unsanitary environments, which can easily lead to diarrhea and food poisoning. Therefore, polluted environments and poor wastewater management create favorable conditions for viruses to emerge and cause illness. Food and vegetables that haven't been properly cleaned and washed, along with street food that hasn't been prepared hygienically or stored correctly, are common causes of food poisoning.