Human metapneumovirus (hMPV) is an RNA virus of the Paramyxoviridae family, first identified in 2001. It is a significant cause of acute respiratory tract infections (ARTIs) in children, the elderly, and immunocompromised individuals. The impact of hMPV on these vulnerable populations can be substantial, often resulting in severe illnesses requiring hospitalization and intensive care.
Causes:
hMPV is transmitted via respiratory droplets and direct contact with contaminated surfaces. Individuals can become infected by inhaling droplets containing the virus or by touching contaminated surfaces and then touching their eyes, nose, or mouth. The virus exhibits a seasonal pattern, with higher incidence in late winter to early spring in temperate climates. This seasonal variation suggests that hMPV transmission is facilitated during colder weather when people are more likely to be indoors and in close proximity.
hMPV's ability to survive on surfaces for extended periods underscores the importance of good hygiene practices, such as frequent handwashing and disinfecting high-touch areas. Avoiding close contact with sick individuals can also help prevent the spread of the virus.
Symptoms:
hMPV infection symptoms range from mild upper respiratory tract issues (cough, rhinorrhea, fever) to severe lower respiratory tract conditions (bronchiolitis, pneumonia). In children, it may cause bronchiolitis and croup, while in adults, it often manifests as a cold or flu-like illness. Severe disease is more common in immunocompromised patients and the elderly, who may experience pronounced symptoms such as difficulty breathing, wheezing, and chest pain.
In some cases, hMPV infection can lead to complications such as respiratory failure, necessitating mechanical ventilation. This highlights the importance of seeking medical attention if symptoms persist or worsen over time.
Diagnosis:
Reverse transcription-polymerase chain reaction (RT-PCR) is the preferred diagnostic method due to the difficulty of culturing the virus. Other diagnostic tools include immunofluorescent assays and nucleic acid amplification tests (NAATs). The American Society for Microbiology and the Infectious Diseases Society of America recommend testing respiratory secretions or nasopharyngeal swabs. These methods enable healthcare providers to quickly identify hMPV infection and offer appropriate treatment.
Because hMPV symptoms often resemble those caused by other respiratory viruses, a thorough medical evaluation is necessary to determine the underlying cause of illness.
Treatment:
Currently, there are no specific antiviral treatments approved for hMPV. Management is primarily supportive, including hydration, oxygen therapy, and mechanical ventilation when necessary. Ribavirin has shown in vitro activity, but its clinical efficacy remains unproven. Immunoglobulins and monoclonal antibodies are under investigation but are not yet available for clinical use.
Supportive care is essential in managing hMPV infection. Ensuring adequate hydration can help thin mucus secretions, making them easier to expel, while oxygen therapy supports breathing in cases of hypoxia caused by pneumonia or other complications.
Prevention:
Preventive measures focus on infection control practices such as hand hygiene and contact precautions. Although no vaccines are currently available, several candidates are under development. This emphasizes the importance of infection control, particularly for high-risk populations such as transplant recipients, where stringent protocols should be followed to minimize disease transmission.
