Is dengue the new pandemic? – Firstpost

The last few months have seen a surge in dengue cases across the world. According to data from the European Centre for Disease Control and Prevention, a total of more than 12 million dengue cases and over 8,000 dengue-related deaths have been reported in 86 countries since the beginning of 2024. Among these countries, Brazil has reported the highest number of cases this year, with over 9 million, followed by Argentina, Paraguay, Peru and Colombia.

According to data published on the website of the National Centre for Vector Borne Disease Control, India has reported 19,447 dengue cases and 16 deaths as of April 30, 2024. The highest number of dengue cases will be reported in 2023, when 4.5 million cases will be reported in the WHO Americas region, with 2300 deaths. The highest number of cases reported in Asia are: Bangladesh (321 000), Malaysia (111 400), Thailand (150 000), and Vietnam (369 000).

Figure 1. Epidemic curve of dengue cases and deaths reported to WHO from January to April 2024*

Speaking to Firstpost about the current treatment protocol for dengue fever, Dr Tushar Tayal, consultant, internal medicine, CK Birla Hospital (Gurugram), said the primary focus of treating dengue fever is supportive care, which focuses on managing fluids to prevent dehydration, especially in severe cases like dengue hemorrhagic fever or dengue shock syndrome.

“Paracetamol is used to relieve pain and reduce fever. However, non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin or ibuprofen are not recommended as they may increase the risk of bleeding. Continuous monitoring of vital signs and clinical parameters is essential to identify any progression towards severe dengue,” he added.

Important Facts

*Dengue is a viral infection that is primarily spread by the bite of infected female Aedes aegypti mosquitoes. These mosquitoes usually bite during the day, with the most bites occurring during the morning and evening. It is more common in tropical and subtropical climates.

*Dengue is a viral infection that spreads to humans through the bite of infected mosquitoes.

*Dengue is found in tropical and subtropical climates worldwide, mostly in urban and semi-urban areas.

*Although many dengue infections are asymptomatic or cause only mild illness, the virus can occasionally cause more severe cases and even death.

*Prevention and control of dengue depends on vector control. There is no specific treatment for dengue/severe dengue, and early detection and access to appropriate medical care greatly reduces the mortality rate of severe dengue.

Dr Tushar said factors contributing to the spread of dengue include high population density and poor sanitation, which create breeding grounds for mosquitoes. He said hot, humid climate and rainy season promote mosquito breeding.

symptoms

*Most people with dengue have mild or no symptoms and recover within 1-2 weeks. Occasionally, dengue can be severe and cause death. If symptoms do appear, they usually begin 4-10 days after infection and last 2-7 days. Symptoms may include high fever (40°C/104°F), severe headache, pain behind the eyes, muscle and joint pain, nausea, vomiting, swollen glands, and rash.

*People who get infected a second time are at higher risk of developing severe dengue.

Diagnosis and treatment

There is no specific treatment for dengue. The focus is on treating pain symptoms. Most cases of dengue fever can be treated at home with pain medication. According to WHO, acetaminophen (paracetamol) is often used to control pain. Non-steroidal anti-inflammatory drugs such as ibuprofen and aspirin should be avoided as they may increase the risk of bleeding.

Role of fluid management in the treatment of dengue

Dr Tushar said effective fluid management is a crucial aspect in treating dengue, especially in severe cases. The primary aim is to prevent or manage dehydration and shock caused by plasma leakage, a common complication in severe dengue, he said, adding that in mild cases, oral rehydration is recommended, while in more severe cases or when oral intake is inadequate, fluids are given through veins. The aim is to strike a balance in fluid administration to prevent dehydration and prevent blood thickening, he added.

The importance of monitoring platelet count and other blood parameters

According to Dr. Tushar, regular monitoring of blood parameters is very important for patients suffering from dengue. This includes frequent checking of the following:

platelet count: Monitoring platelet levels helps assess the risk of bleeding, particularly if the count drops below 10,000, indicating a possible increase in bleeding risk.

Hematocrit level: Hematocrit monitoring is important to detect hemoconcentration (a sign of plasma leakage), which can cause severe dengue.

Liver Function Tests (LFTs): LFT monitoring helps assess liver injury and possible liver failure, a rare but serious complication of dengue.

In moderate cases of dengue, platelets and other parameters are generally checked daily. However, in severe cases, monitoring may be required every 12 hours, depending on the clinical condition of the patient, to ensure timely intervention and appropriate management.

Infection through mosquito bites

The dengue virus is transmitted to humans by the bite of infected female mosquitoes, primarily the Aedes aegypti mosquito. Other species within the Aedes genus can also act as vectors, but their contribution is usually secondary to that of Aedes aegypti. However, in 2023, an increase in local transmission of dengue by Aedes albopictus (tiger mosquito) has been observed in Europe.

Dietary guidelines and lifestyle precautions for patients

It is important for dengue patients to follow the necessary dietary guidelines and take lifestyle precautions. Dr Tushar has given some suggestions:

Hydration: Drinking enough water is very important, especially for dengue patients, to prevent dehydration. Water, oral rehydration solutions, and fresh juices are recommended.

Diet: A balanced and nutritious diet is essential for being healthy. Eat easily digestible foods rich in vitamins, minerals and proteins, such as soups, boiled vegetables, porridge and fruits. Avoid eating fatty and spicy foods, as they may be difficult to digest and may worsen the disease.

RestAdequate rest is very important for the immune system to recover. Patients should ensure that they get enough rest to help them recover.

MedicineAs mentioned earlier, non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin and ibuprofen should be avoided due to the increased risk of bleeding.

human to mosquito transmission

Mosquitoes can be infected by people who are infected with the dengue virus. This can be someone who has a symptomatic dengue infection, someone who has not yet had a symptomatic infection (they are pre-symptomatic), and someone who does not show any symptoms of the disease (they are asymptomatic).

Transmission from humans to mosquitoes can occur up to two days before symptoms of the disease appear and up to two days after the fever subsides.

The risk of mosquito infection is positively associated with high viremia and high fever in the patient; in contrast, high levels of DENV-specific antibodies are associated with a lower risk of mosquito infection. Most people suffer from viremia for about 4-5 days, but viremia can last up to 12 days.

Maternal transmission

The primary route of transmission of dengue virus among humans is through mosquito vectors. However, there is evidence for the possibility of maternal transmission (from a pregnant mother to her baby). Also, while vertical transmission rates appear to be low, the risk of vertical transmission appears to be associated with the timing of dengue infection during pregnancy. When a mother has a dengue infection while pregnant, babies may suffer from premature birth, low birth weight, and fetal distress.

Other transmission modes

Rare cases of infection through blood products, organ donation and transfusion have been reported. Similarly, transovarial transmission of the virus within mosquitoes has also been recorded.

Prevention

*Mosquitoes that spread dengue are active during the day.

*To reduce the risk of getting dengue, wear clothes that cover as much of your body as possible and use a mosquito net if sleeping during the day.

*Preventing mosquitoes from accessing egg-laying habitats through environmental management and modification.

*Proper disposal of solid waste and removal of artificial man-made habitats that hold water.

*Household water storage containers should be covered, emptied and cleaned every week as it thrives in fresh water.

Severe symptoms of dengue often continue even after the fever has gone away:

* Severe pain in the stomach

*Continuous vomiting

*Rapid breathing

*Bleeding from gums or nose

*Tiredness

*Restlessness

*Blood in vomit or stool

*Feeling very thirsty

* Pale and cold skin

*Feeling weak.

Global burden

Recent decades have seen a dramatic increase in global cases of dengue, with the number of cases reported to the World Health Organization (WHO) rising from 505,430 in 2000 to 5.2 million in 2019. Globally, dengue cases have increased significantly over the past five years, with a notable increase in the region of the Americas. By the end of April 2024, more than 7 million cases have been reported in the region, surpassing the previous annual high of 4.6 million cases in 2023.

However, because most cases are asymptomatic or mild and self-managed, the actual number of dengue cases is underreported. In addition, many cases are misdiagnosed as other febrile illnesses, leading to an underestimation of the true burden of disease.

The year 2023 saw the highest number of dengue cases ever recorded, affecting more than 80 countries across all WHO regions. Ongoing infections and an unexpected surge in cases have led to more than 6.5 million cases and more than 7,300 dengue-related deaths since the beginning of 2023.

Several factors are contributing to the increased risk of a dengue epidemic, including the changing distribution of vectors, such as Aedes aegypti and Aedes albopictus mosquitoes, particularly in previously unaffected countries. In addition, the El Niño event in 2023 and the consequences of climate change, which lead to increased temperatures and higher rainfall and humidity, also play a role.

The situation has been made worse by weak health systems, as well as political and financial instabilities in countries facing complex humanitarian crises and high population movements during the COVID-19 pandemic.

Dengue is now endemic in more than 100 countries in Africa, the Americas, the Eastern Mediterranean, Southeast Asia, and the Western Pacific. The Americas, Southeast Asia, and the Western Pacific are the most severely affected, with Asia accounting for about 70% of the global disease burden. In addition, dengue is spreading to new areas in Europe, the Eastern Mediterranean, and South America.

Source: With inputs from World Health Organisation.