Monday, March 25, 2024

Vietnam MOH Statement: Epidemiological Investigation Into Human H5N1 Infection

 Credit Wikipedia 


Overnight Vietnam's Ministry of Health published a detailed report on the fatal A/H5 case reported on Friday (see here, here, and here), one which answers several pressing questions.  

  • First, it confirms the subtype as H5N1, although the clade remains unspecified.
  • Second, it provides a plausible route of infection; the patient trapped wild birds both before and after the Lunar New Year Celebration.
  • And third, no new infections have been detected (although monitoring of close contacts continues).

First the (translated) statement, after which I'll have brief comment.

​Information about cases of Influenza A(H5N1) in Khanh Hoa


The Department of Preventive Medicine announces a case of influenza A(H5N1) as follows:

Male patient, 21 years old
, residing in Tan Ninh village, Ninh Trung commune, Ninh Hoa town, Khanh Hoa province. On March 11, 2024, the patient developed symptoms of fever and cough and self-treated but the symptoms did not improve. The patient came for examination and treatment at Ninh Hoa Medical Center on March 16-17, 2024, then the patient was transferred to Khanh Hoa General Hospital for treatment with a diagnosis of pneumonia. On March 19, 2024, Khanh Hoa Center for Disease Control took patient samples for testing; According to test results on March 20, 2024, the patient was positive for influenza A/H5 and confirmation results from Nha Trang Pasteur Institute on March 22, 2024 determined that the patient was positive for influenza A(H5N1). Due to the serious progression of the disease, the patient died on March 23, 2024.

According to the results of the epidemiological investigation, on the occasion before and after the Lunar New Year 2024, the patient went to trap wild birds near the area where the patient lived; There were no sick or dead poultry around the area where the patient's family lived. Cases of close contact with patients are listed and their health monitored daily; To date, no new cases have been detected.

This is the second case of influenza A(H5N1) since 2014 after many years of no human cases being recorded in Vietnam. Previously, in October 2022, 01 case of influenza A(H5N1) in humans was recorded in Phu Tho. Accumulated from 2003 to present, the country has recorded 128 people infected with influenza A(H5N1), of which 65 died (50.8%).

In the world, from the end of 2023 until now, many outbreaks of avian influenza in animals have been recorded in all regions, mainly due to the influenza A (H5N1) virus strain. In Cambodia, continued to record cases of influenza A(H5N1) in humans since the end of 2023. Domestically, according to information from the Department of Animal Health - Ministry of Agriculture and Rural Development, avian influenza epidemic is still recorded sporadically in poultry flocks in many localities across the country. From the beginning of 2024 until now, 06 bird flu outbreaks have been recorded in 06 provinces and cities including Bac Ninh, Ninh Binh, Khanh Hoa, Ba Ria - Vung Tau, Long An and Tien Giang. Besides, this time is the changing season, and unusual weather changes are favorable conditions for pathogens to grow. The Ministry of Health said that in the coming time, there is still a potential risk of avian flu infection to humans.

There is currently no specific treatment for avian influenza in humans and no vaccine to prevent the disease. Currently there is no evidence that influenza A(H5N1) is transmitted from person to person. The A(H5N1) virus is a highly virulent strain of influenza, infected people often develop severe disease and die at a high rate (~50%). ). To proactively prevent and control influenza A(H5N1) transmitted from poultry to humans, people need to well implement the following measures:
1. Do not eat poultry or poultry products that are sick, dead or of unknown origin; Make sure to eat cooked food and drink boiled water; Wash hands with soap before eating.
2. Do not slaughter, transport, buy or sell poultry and poultry products of unknown origin.
3. When discovering sick or dead poultry, absolutely do not slaughter or use it, but must immediately notify the local authorities and veterinary unit in the area.
4. Limit contact, slaughter, and eating of wild animals, especially birds.
5. When you have flu symptoms such as fever, cough, chest pain, difficulty breathing related to poultry, you must immediately go to a medical facility for timely consultation, examination and treatment.
Editorial board of the website of the Department of Preventive Medicine

While direct or indirect contact with infected poultry has long been viewed as the biggest risk factor for contracting avian flu, increasingly we are seeing warnings about the risks posed by wild birds.  

    • An epidemiological investigation being conducted by the Ministry of Health ascertained that the patient’s residence is located one block from the seashore where seabirds infected with H5N1 viruses had previously been detected. For that reason, an infection of environmental origin is suspected.

The risks to humans from infected birds likely remains quite low, but that risk is arguably higher for dogs and cats which roam outside (see Netherlands: Utrecht University Study Of Stray & Domestic Cats For Evidence Of HPAI H5N1 Exposure), which could provide additional routes of human exposure.

While rare, people have contracted avian flu from pets in the past (see J Infect Dis: Serological Evidence Of H7N2 Infection Among Animal Shelter Workers, NYC 2016), and we've seen guidance from both the CDC (see Bird Flu in Pets and Other Animals) and the UK's DEFRA on the importance of keeping pets safe from H5N1.

All of these are considerations to which - until relatively recently - people living in the Americas, and much of Europe, had to give little thought.  But, at least in the short term, this appears to be our `new normal'.