Dominant Dengue Virus Serotype Changes

KOMPAS/IWAN SETIYAWAN

Fumigation to prevent the spread of dengue fever mosquitoes is carried out in a residential area in Cinangka, Sawangan, Depok, West Java, on Sunday (17/02/2019). The Depok city government continues to promote the prevention of the spread of dengue fever because in January there were 436 sufferers, an increase of 75 compared to the corresponding period last year.

Dengue hemorrhagic fever (DHF) has spread across several regions in the country. Many people have died due to complications from the disease. Some have suspected that the dengue virus has mutated into a more malignant form, but this does not appear to be the case.

Tedjo Sasmono, the head of the dengue unit at the Eijkman Molecular Biology Institute, said that genomic mutations could increase virulence, such as in Latin America. However, no mutations directly connected to the severity of the disease have been found from among the hundreds of Indonesian dengue virus genomes that were studied.

All serotypes (DENV-1, DENV-2, DENV-3, DENV-4) exist in Indonesia. The dominant dengue serotype varies in each region. It is common for the serotypes to rotate in their dominance in Indonesia. In Jakarta, DENV-3 was dominant in 2014 and DENV-2 in 2008, which was overtaken by DENV-1 in 2009. DENV-3 was the dominant serotype in 1998 in Palembang, while DENV-1 was dominant in 2015 in Jambi, which neighbors Palembang.

"The [serotype diversity] pattern is as yet unknown, because virus surveillance is sporadic and not regularly carried out every year," said Tedjo.

The severity of dengue is due to a combination of both viral and human factors (immune response). DENV-2 and DENV-3 often cause greater clinical severity compared to DENV-1 and DENV-4. Viruses that have higher replication rates tend to be more virulent. The immune response is specific to each individual. Some influential factors include age (children tend to experience plasma leakage more than adults), gender (women tend to have more severe responses than men), nutritional status (overweight children tend to experience more severe symptoms). In addition, secondary infections tend to be more severe than primary infections.

Dengue-related deaths can be prevented if we can recognize the symptoms and seek immediate help. Dengue fever is always marked by an increase in body temperature, but not always by skin rashes.

Tropical infections and pediatrics chairman Mulya Rahma Karyanti, of Cipto Mangunkusumo General Hospital’s pediatrics department and the University of Indonesia medical school, said on Saturday that skin rashes were an indication of a lower platelet count or increased vascular permeability. However, they were not always caused by dengue infection. It could also be due to idiopathic thrombocytopenic purpura (ITP), an autoimmune disorder that causes an abnormally low platelet count. A blood test for dengue nonstructural protein 1 (NS1) antigen, or the NS1 antigen test, is necessary to detect a dengue virus infection.

"The symptoms to watch out for are abdominal pain, vomiting, diarrhea, infrequent urination, febrile seizures. If the fever subsides but the patient looks weak, plasma could be leaking from the blood vessels [into the surrounding tissue]," said Mulya.

Plasma leakage causes the blood to thicken, the volume of blood to decrease and disrupts blood circulation. This condition is known as hypovolemic shock. As a result, the organs lack oxygen and will lead to organ failure and death. Patients must be taken to the hospital immediately to receive fluid transfusions. The critical stage generally lasts 48 hours, after which the patient will gradually begin to cover.