Dengue: a small mosquito bite with a bigger life threat.

Between 1 January and 27 September 2022, a total of 25 932 confirmed dengue cases and 62 deaths (CFR 0.25%) were reported in Pakistan, with 74% of these cases reported in the month of September alone. The current surge in cases follows unprecedented flooding that began in mid-June 2022. With the current flood crisis affecting the national health system capacity and the growing humanitarian situation, there is a high risk of serious health impacts from dengue fever and other concurrent disease outbreaks.

Dengue and it's serotypes:

Dengue is a viral infection transmitted to humans through the bite of infected mosquitoes. The main vector for this disease is Aedes aegypti and, to a lesser extent, Ae. Albopictus.

Dengue infections are caused by four closely related viruses named DEN-1, DEN-2, DEN-3, and DEN-4. These four viruses are called serotypes because each has different interactions with the antibodies in human blood serum. The four dengue viruses are similar — they share approximately 65% of their genomes — but even within a single serotype, there is some genetic variation. Despite these variations, infection with each of the dengue serotypes results in the same disease and range of clinical symptoms.

Dengue virus transmission:

Dengue cannot be spread directly from one person to another. Rather, the virus is spread through the bite of an infected female Aedes aegypti mosquito.
When an uninfected mosquito bites a person who has the virus in their bloodstream, the mosquito becomes infected. An infected mosquito can then transmit that virus to a healthy person by biting them, thus creating a cycle.
Infected mosquitoes can continue transmitting the virus to healthy people for their entire life span which generally lasts three to four weeks.
According to the WHO, the global spread of dengue has increased immensely in recent decades and is regarded as one of the 17 neglected tropical diseases (NTDs).

Symptoms and Precautions:

Understanding how dengue might be recognised and identified early is crucial. The first symptoms following a mosquito bite might appear between 4 and 10 days later. Dengue infection symptoms include high-grade fever (up to 104 °F), cough, retro-orbital (behind the eyes) headache, body pain and aches, diarrhoea, and vomitting. In cases of dengue hemorrhagic fever, there may be bleeding from the gums and gastrointestinal system, which, if not recognised and treated promptly, can be deadly.

There is no single antiviral medication that can treat dengue. Maintenance therapies are crucial, including oral rehydration, antipyretics to reduce fever, etc. The best care for patients with more severe symptoms, particularly those suspected of having hemorrhagic fever, is provided in a hospital. Elderly dengue patients have a higher risk of hemorrhagic fever and shock and may appear in an unusual way. In addition to the severity of the dengue, age and the existence of co-morbid illnesses are linked to lengthy hospital stays.

It is ideal to seek correct precautionary steps to help reduce the risk of contracting dengue. Here are preventive measures to help you lower the risk of dengue and other mosquito-borne diseases:

• Removing the opportunity for these mosquitoes to reproduce in an environment containing stagnant water. This may lessen the risk of dengue.
• One can wear long-sleeved clothing, complete pants with socks, and covered shoes to prevent mosquito bites. It is best to wear this type of protective clothing, especially in locations where dengue is prevalent.
• You can get two layers of protection from mosquito bites by sleeping under a mosquito net.
• Using mosquito repellents can help prevent mosquito bites, particularly in tropical locations with dense populations and crowds. When visiting tropical locations and even when you are indoors, apply mosquito repellent ointment to your body.
  

These precautionary steps can help you lower your risk of developing mosquito-borne diseases.

WHO Advice:

WHO promotes the strategic approach known as Integrated Vector Management (IVM) to control mosquito activity and population, including Aedes spp. (the vector of dengue). 

IVM activities should be enhanced to remove potential breeding sites, reduce vector populations, and minimize individual exposure. This should involve vector control strategies for larvae and adults (i.e. environmental management and source reduction, and chemical control measures), as well as strategies for protecting people and households. Vector control activities should focus on all areas where there is human-vector contact (place of residence, workplaces, schools and hospitals). 

Vector control activities can include covering, draining and cleaning household water storage containers on a weekly basis. In addition, this may include chlorination of drinking water and application of suitable larvicides/insecticides for water storage in outdoor containers.

In addition, vector and human case surveillance should continue to be enhanced in all affected areas and across the country. Key public health messages on reducing the risk of dengue transmission among the population are expected to continue to be provided.