The Centers for Disease Control and Prevention (CDC) has announced plans to investigate samples collected from a fatal swine flu infection in Brazil, according to a statement by the World Health Organization (WHO). The investigation was initiated after it was discovered that the fatality resulted from an H1N1 variant spreading among pigs.

In various instances, occasional spillovers of the H1N1 swine flu have been identified worldwide in individuals who had contact with infected pigs. However, it remains uncertain how the patient in this particular case contracted the virus. The deceased, a 42-year-old woman residing in the Brazilian state of Paraná, had never directly interacted with pigs.

The woman developed a fever, headache, abdominal pain and sore throat on May 1. She was hospitalized on May 3 due to a severe acute respiratory infection. She got admitted to the intensive care unit (ICU) the following day but died on May 5, according to the WHO's statement.

Investigators discovered that two of the patient's close contacts worked at a nearby pig farm. However, both individuals tested negative for influenza and displayed no respiratory symptoms.

"Based on the information currently available, WHO considers this a sporadic case, and there is no evidence of person-to-person transmission of this event. The likelihood of community-level spread among humans and/or international disease spread through humans is low," the WHO noted.

Initial analyses conducted by health authorities in Brazil have confirmed that the virus responsible for the fatality is an H1N1 strain closely related to previously observed samples in the region.

"To date, sporadic human infections caused by influenza A(H1N1)v and A(H1N2)v viruses have been reported in Brazil, and there has been no evidence of sustained human-to-human transmission," the organization added.

A CDC spokesperson said they have not yet received the specimen from Brazilian authorities. The CDC, as one of the WHO's collaborating centers, plays a crucial role in global flu surveillance efforts. The public health agency regularly studies thousands of sequenced flu viruses collected each year, comparing their genetic makeup with previous variants that have infected animals and humans.

This summer, the Biden administration has been actively planning to enhance efforts to detect cases of potentially deadly new flu variants spreading to humans, according to CBS News.

Alongside the escalating threat posed by the widespread avian flu outbreak among birds in the Americas, previous years have witnessed incidents of "novel influenza virus infections" following human-animal interactions at events such as agricultural fairs.