Ho Chi Minh City’s Department of Health has confirmed that a child patient diagnosed with encephalitis caused by the avian influenza virus A/H5N1 is currently receiving treatment at Children’s Hospital 1.

This is a rare case, as the virus has affected the central nervous system rather than the respiratory tract.

The patient is a 7-year-old girl, L.B.A., from Ben Cau district, Tay Ninh province. She was admitted with high fever, headache, projectile vomiting, altered consciousness, incoherent speech, and mild neck stiffness.

Prior to her transfer, she was treated at a provincial hospital without improvement. She was admitted to Children’s Hospital 1 on April 13 with an initial diagnosis of encephalitis - meningitis.

Doctors collected cerebrospinal fluid (CSF) and respiratory samples for testing. On April 17, PCR results showed the CSF sample was positive for influenza A/H5, while the respiratory sample was negative.

The Pasteur Institute in Ho Chi Minh City confirmed on April 18 that the girl tested positive for A/H5N1 in her CSF and negative in her nasal and throat swab.

This indicates a rare form of the disease, where the virus invades the central nervous system without attacking the typical respiratory tract.

The patient is currently being treated in the infectious disease intensive care unit, on mechanical ventilation, and is able to open her eyes naturally. Her temperature is 38.5°C, and her vital signs are temporarily stable.

According to infectious disease experts, this is an extremely rare case where the A/H5N1 avian flu virus affects the central nervous system without involving the respiratory system.

Normally, A/H5N1 causes outbreaks among poultry and waterfowl, and humans become infected through close contact with infected or dead birds.

The primary symptom in avian flu infections is severe pneumonia, often progressing to acute respiratory distress syndrome (ARDS), with a mortality rate of over 50%. Fortunately, the A/H5N1 virus has not yet demonstrated human-to-human transmission.

Cases of H5N1-related encephalitis have been previously documented in global medical literature. During the 2004 H5N1 avian flu outbreak in humans in Dong Thap province, researchers from the Oxford University Clinical Research Unit (OUCRU), in collaboration with the Hospital for Tropical Diseases and Children’s Hospital 1, detected A/H5N1 in the CSF of two children.

These children experienced severe diarrhea, seizures, and coma before succumbing to the illness, despite showing no respiratory symptoms. These findings were published in the New England Journal of Medicine in 2005.

Preliminary epidemiological investigations revealed that the girl had been exposed to a mass die-off of chickens at her grandmother’s home around two weeks prior.

She also has a history of congenital heart disease (ventricular septal defect), which was surgically corrected at Children’s Hospital 1 when she was two months old.

The Ho Chi Minh City Department of Health has directed the city's Center for Disease Control (CDC) to coordinate with Tay Ninh CDC to investigate, contain, and manage the outbreak according to regulations. A rapid report has also been sent to the Ministry of Health.

Phuong Thuy