As dengue instances rise quickly throughout many components of the nation and Delhi witnesses a exceptional surge in folks affected by the illness, it is time to observe all precautions, even if in case you have recovered from dengue within the current or distant previous. Unlike many viral infections, dengue virus (DENV) may be deadlier for you in case of repeat an infection. While an individual who has recovered from a selected serotype of dengue stays protected against the an infection from all serotypes of dengue for 2-3 months, after this temporary window, the safety wanes and the particular person can get contaminated by the remainder of the serotypes. There are 4 serotypes of dengue presently – DENV-1, DENV-2, DENV-3 and DENV-4. (Also learn: Dengue during pregnancy can turn fatal; know complications, symptoms and prevention tips)

This behaviour of dengue virus could appear peculiar at first look as often with different viral infections together with Covid, the physique remembers the an infection for a very long time by its reminiscence B cells and reminiscence T cells. However, in case of dengue the physique solely remembers an infection from the serotype that precipitated an infection and offers immunity solely towards that specific pressure. When contaminated with different serotypes, the signs of dengue can develop into worse, antibodies from the first an infection could assist unfold the dengue viral an infection.

Why folks get second dengue an infection

“The risk of getting a second dengue infection is as common as the first one because it occurs due to vector-borne disease and mosquito bites. It is all a matter of destiny that somebody experiences a second dengue attack, which happens because of the second mosquito bite. However, the course and clinical presentation of the disease can change the incubation period, which is generally 3 to 8 days but can shorten to as little as one day to three days. This means that the symptoms may start as early as one day after the mosquito bite and reach their maximum within five days,” says Dr Anantha Padmanabha, advisor, inside drugs, Fortis Hospital, Nagarbhavi, Bengaluru.

Why severity of second assault is larger

“Dengue virus, which belongs to the Flaviviridae family, consists of four distinct serotypes, namely DEN-1, DEN-2, DEN-3, and DEN-4. After the first infection, individuals develop specific antibodies targeting the infecting serotype. When encountering a different serotype during a subsequent infection, these pre-existing antibodies can interact with the new virus particles in a phenomenon called ADE. During ADE, the antibodies generated against the first dengue serotype bind to the new virus particles but fail to neutralize them effectively. Instead, the virus-antibody complexes are taken up by immune cells through Fc receptors, which can lead to increased viral replication. This process potentiates viral infection, triggering a more robust immune response characterized by excessive cytokine release and activation of immune cells. Consequently, this heightened immune response can result in severe dengue symptoms, such as haemorrhage, organ failure, and shock,” says Dr Hyacinth Peninnah Paljor, Senior Consultant, Dept of Internal Medicine, Amrita Hospital, Faridabad.

“The severity of a dengue infection can be higher when people experience a second attack because preformed antibodies are already present in the patient from their previous exposure to the dengue virus. As a result, the antibody levels peak early, and the platelet count may decrease significantly in a short period during a fresh dengue infection. Normally, platelet levels may decline around the fifth or fourth day and continue to decrease for 7-8 days before starting to recover. However, in the case of a second attack within one year of the first dengue infection, the platelet count falls rapidly, and there is a higher risk of developing a dreaded complication known as dengue shock syndrome (DSS),” provides Dr Padmanabha.

“Several factors contribute to the increased risk of severe dengue in individuals experiencing a second infection. First, the presence of cross-reactive but non-neutralizing antibodies from the previous infection enables ADE to occur. Second, the sequence of dengue virus serotypes to which an individual is exposed can influence the severity of subsequent infections. For instance, sequential infections with DEN-2 followed by DEN-3 or DEN-4 have been associated with a higher risk of severe dengue,” says Dr Paljor.

DSS can happen extra typically in people who expertise a second dengue assault inside one yr of the primary one. In this situation, they might expertise bleeding all through the physique, a drop in blood stress, and even bleeding within the intra-abdominal and cerebral areas, that means within the mind. This is a critical complication that may come up attributable to dengue shock syndrome.

How to stop second an infection

“Given the increased risk of severe dengue in individuals with a second infection, prevention and control strategies become crucial. Vector control measures, such as eliminating mosquito breeding sites and using insecticides, remain vital in reducing dengue transmission. Additionally, public health efforts should focus on raising awareness about the risks associated with sequential dengue infections and the importance of seeking medical attention promptly when symptoms arise,” says Dr Paljor.