BHUBANESWAR: Researchers have found dengue virus serotype-2 (DENV-2 or D2), the most virulent strain, and co-infection of two subtypes in samples drawn from patients from different parts of the Odisha, including capital Bhubaneswar that has witnessed a sudden spurt, recording nearly 400 cases in the last one month.
The co-infection of D1 and D2 apart from D2 and D3 that are deemed to cause severity in the disease have been found in samples collected from Bhubaneswar, Rayagada, and Koraput. D2 has been found in one sample each from Malkangiri and Nabarangpur.
Dengue virus comprises four antigenically distinct groups designated as serotypes D1 to 4. Dengue hemorrhagic fever and dengue shock syndrome that can cause fatality is more associated with D2 than with the other serotypes.
Sources said the serotyping of 56 dengue positive cases carried out by the Regional Medical Research Centre (RMRC) of ICMR, recently, has shown that 51 have D1 serotype and three co-infection of D1 and D2.
“Three serotypes - D1, D2, and D3 are in circulation in the State of which the subtype-2 is most pathogenic. Its second attack is more dangerous as the macrophages facilitate viral entry. This subtype also leads to dengue shock syndrome,” said a scientist at RMRC.
Of the 547 dengue-positive cases registered in the State this year so far, 422 cases, including 48 on Wednesday, were from Khurda alone. It has spread its tentacles to 15 districts, including 30 from Cuttack, 19 from Puri, 10 each from Jajpur and Nayagarh, and eight from Balasore.
After reviewing the dengue situation, Director of Public Health Dr Niranjan Mishra said that source reduction and public awareness are the keys to controlling the outbreak. “Apart from intensifying IEC activities, we have deployed dengue volunteers in the affected areas. People are being encouraged for testing and patients asked to keep themselves hydrated to respond to treatment,” he added.
Dengue cases were less last year as compared to previous years, possibly due to the Covid-19 outbreak restricting the movement of people. While only 496 cases were detected in 2020, the highest 8,380 cases and 11 deaths were recorded in 2016, 4,158 cases and six deaths in 2017, 5,198 cases and five deaths in 2018, and 3,758 cases and four deaths in 2019.
The co-infection of D2 and D3 was noticed during the dengue outbreak last year in Rayagada, which had recorded the highest 170 cases, followed by 63 in Khurda, 58 in Cuttack, and 40 in Koraput.
“As many as 30 samples showed co-infection with D2 and D3 in Rayagada. Of the 109 samples sent from five different blocks of the district for serotyping, five samples were found negative in PCR test and the rest were with D2 and D3,” the scientist informed.
A recent study by RMRC on 191 outbreaks caused by different viruses between September 2010 and September 2019 in Odisha found the most common causes of the outbreaks were viral hepatitis, followed by dengue.
Dengue is the second most common type of outbreak in the State, which has reported 45 dengue outbreaks during the period. The frequency of reported outbreaks of infectious diseases has increased manifold. The mean age of the suspected cases for dengue was 30.3 years and the most common age group affected by dengue infection was 11-20 years.