The Bhutanese Leading the way.
The Royal Centre for Disease Control (RCDC), under the Ministry of Health, has observed a notable increase in influenza activity in Bhutan over the last two weeks. The observation is based on the biweekly National Respiratory Virus Sentinel Surveillance conducted for epidemiological weeks 13 and 14, covering the period from 24th March to 6th April.
Week 13 refers to the period from 24th March to 30th March, while week 14 spans from 31st March to 6th April.
During week 13, the flu positivity rate stood at 23.5 percent, with 28 out of 120 tested individuals confirming positive for influenza.
In the following week, the positivity rate rose to 29.2 percent, with 33 out of 113 individuals testing positive. This marks a gradual but consistent rise in flu cases across the country.
A total of 232 samples were tested over the two weeks. These samples were collected from individuals presenting with Influenza-like Illness (ILI), Severe Acute Respiratory Infection (SARI), and outbreaks of Acute Respiratory Infection (ARI).
Out of the total samples, 61 tested positive for influenza. The majority of these were identified as Influenza A, particularly the H3 subtype. A smaller number of cases were Influenza B and Influenza A (H1 subtype).
Influenza viruses that commonly infect humans are mainly classified into two types: Influenza A and Influenza B. Influenza A is typically the more severe and widespread of the two, often responsible for seasonal flu epidemics and even pandemics. It is further divided into subtypes based on two surface proteins—hemagglutinin (H) and neuraminidase (N). The most common subtypes affecting humans are H1N1 and H3N2.
In the given report, the majority of the cases were identified as Influenza A, particularly the H3 subtype (H3N2), which is known to spread rapidly and cause significant illness, especially in vulnerable populations. A smaller number of cases were found to be Influenza B and Influenza A of the H1 subtype (H1N1), both of which also contribute to seasonal flu outbreaks but are generally less common than H3N2.
The surveillance samples were collected from sentinel sites across the country, targeting both Influenza-Like Illness (ILI) and Severe Acute Respiratory Infection (SARI) cases.
ILI is characterized by the sudden onset of fever and cough among individuals who do not require hospitalization, whereas SARI refers to more severe cases of respiratory illness that typically need hospital admission and close medical attention.
Notably, no cases of Respiratory Syncytial Virus (RSV) or COVID-19 were reported during this surveillance period.
RSV, although commonly associated with mild cold-like symptoms, can cause serious illness in infants, the elderly, and people whose immune system is weakened or not functioning properly, making it harder for their body to fight off infections and diseases.
The report also notes that nearly all ILI and SARI sentinel hospitals submitted their data during this period. However, a few health facilities were unable to report due to logistical issues.
Among the reporting hospitals, Jigme Dorji Wangchuck National Referral Hospital (JDWNRH), Phuentsholing Hospital, and Punakha Hospital reported the highest number of influenza cases.
As of early April 2025, only one outbreak of Acute Respiratory Infection has been reported this year. The outbreak occurred at Gedu Higher Secondary School, and no other clusters of respiratory illness have been recorded during the current surveillance period.
In terms of trends, the number of ILI cases saw an increase around week 13, which coincided with the rise in flu positivity rates. SARI cases, on the other hand, remained relatively stable, with 24 cases reported in week 13 and 33 cases in week 14.
The RCDC continues to monitor respiratory illnesses through its nationwide surveillance system, which plays a vital role in early detection and response to seasonal and emerging viruses. With flu activity currently on the rise, the Ministry of Health has urged the public to adopt preventive measures such as frequent handwashing, covering coughs and sneezes, and staying home when unwell.
Health officials are expected to continue issuing timely updates and health advisories to help control the spread of influenza and protect vulnerable populations, including children, the elderly, and people with chronic medical conditions.
