What Is the Influenza Variant Virus in Brazil and How to Protect Yourself

Influenza is a viral infection that affects the respiratory system and can cause mild to severe illness. Influenza viruses constantly change and evolve, creating new variants that may have different characteristics and impact human health. One of the recent Influenza Variant Virus in Brazil is the influenza A (H1N1) variant virus, also known as H1N1v.

What is H1N1v, and how does it differ from other influenza viruses?

The influenza variant virus in Brazil (H1N1v) is a swine-origin influenza virus that has acquired some genetic material from human influenza viruses. The Influenza variant virus in Brazil (H1N1v) belongs to the same subtype as the pandemic influenza A (H1N1) virus that emerged in 2009, also known as H1N1pdm09. However, H1N1v is not the same as H1N1pdm09 and has different antigenic properties, meaning that it may not be recognized by the immune system of people vaccinated or infected with H1N1pdm09.

The Influenza variant virus in Brazil (H1N1v) also differs from other swine-origin influenza viruses detected in humans in the past, such as H3N2v and H1N2v. These viruses have a combination of genes from swine, human and avian influenza viruses, while H1N1v has only genes from swine and human influenza viruses.

How common is the Influenza variant virus in Brazil infection in humans, and how is it transmitted?

H1N1v infection in humans is very rare and sporadic. According to the World Health Organization (WHO), only a few cases have been reported globally since 2005, mostly in people with direct or indirect contact with pigs or pig farms. In Brazil, three cases of H1N1v infection have been confirmed since 2015, including one fatal case that occurred in June 2023.

The main source of the Influenza variant virus in Brazil (H1N1v) infection in humans is exposure to infected pigs or their environment. Pigs are susceptible to swine and human influenza viruses and can act as mixing vessels for new variants. However, there is no evidence of sustained human-to-human transmission of H1N1v so far. The risk of community-level spread among humans and international disease spread through humans is considered low by WHO.

What are the symptoms and complications of H1N1v infection?

The symptoms of Influenza variant virus in Brazil (H1N1v) infection are similar to those of seasonal influenza and may include fever, cough, sore throat, headache, muscle pain, runny nose, and difficulty breathing. Some people may also experience abdominal pain, vomiting, or diarrhea. The severity of illness may vary depending on the individual’s age, health status, and immune response.

Most cases of H1N1v infection are mild and self-limiting, but some may develop complications such as pneumonia, respiratory failure, sepsis, or death. People with underlying medical conditions, such as chronic lung disease, heart disease, diabetes, or immunosuppression, are at higher risk of developing severe illness or complications from H1N1v infection.

How is the H1N1v infection diagnosed and treated?

H1N1v infection can be diagnosed by laboratory testing of respiratory samples collected from suspected cases. The samples are tested for influenza type A viruses using polymerase chain reaction (PCR) methods and then subtyped by analyzing the hemagglutinin (H) and neuraminidase (N) surface proteins. The samples are also tested for a swine influenza marker by PCR to identify potential variant viruses.

The treatment of the Influenza variant virus in Brazil (H1N1v) is mainly supportive and symptomatic, such as providing fluids, antipyretics, and oxygen therapy if needed. Antiviral drugs, such as oseltamivir or zanamivir, may reduce the duration and severity of illness if started within 48 hours of symptom onset. However, the effectiveness of antiviral drugs against the H1N1v virus is not well established and may depend on the susceptibility of the virus strain.

How can H1N1v infection be prevented?

The best way to prevent H1N1v infection is to avoid contact with pigs or pig farms, especially if they are sick or have respiratory symptoms. People who work with pigs or live in areas where pig farming is common should follow good hygiene practices, such as washing hands frequently, wearing protective clothing and equipment, and cleaning and disinfecting surfaces and equipment. They should also monitor their health and seek medical attention if they develop influenza-like symptoms.

No vaccine is currently available for the Influenza variant virus in Brazil (H1N1v), but research is ongoing to develop one. The seasonal influenza vaccine may not protect against the H1N1v virus, as it has different antigenic properties from the circulating influenza viruses. However, the seasonal influenza vaccine is still recommended for people at risk of influenza complications, as it can prevent infection from other influenza viruses that may co-circulate with the H1N1v virus.

Conclusion

The Influenza variant virus in Brazil (H1N1v) is a rare and sporadic influenza variant that has emerged in Brazil and has caused a few human infections, mostly in people who had contact with pigs or pig farms. The virus has not shown the ability of sustained human-to-human transmission, and the risk of community-level spread among humans is low. However, H1N1v infection can cause mild to severe illness and complications, especially in people with underlying medical conditions. Therefore, monitoring the situation closely and implementing appropriate prevention and control measures to reduce the risk of exposure and transmission of the H1N1v virus is important.