MPXV virus particles (in green) adhered to filaments of the Vero cell cytoskeleton. Photo: Debora Ferreira Barreto Vieira
On August 14, 2024, the increase in Mpox cases in the Democratic Republic of the Congo (DRC) and other African countries led the World Health Organization (WHO) to declare, for the second time, a public health emergency of international concern.
The statement followed the recommendation of a committee of independent experts, which pointed to the potential for the outbreak to spread, associated with the rapid spread of a new strain of the mpox virus (MPXV), called clade 1b.
In Brazil, the first case of the variant was confirmed on March 7, 2025, in São Paulo. The patient, a 29-year-old woman, had not visited areas with Mpox outbreaks, but had contact with a family member from RCD.
Prior to the spread of the clade 1b strain, the first emergency declaration occurred in July 2022, when a multinational outbreak caused by MPXV clade 2 was recorded. This emergency ended in May 2023, after a sustained decrease in cases worldwide.
MPXV belongs to the Orthopoxvirus genus, which also includes the pathogens responsible for human and cowpox. It was discovered in 1958, when researchers were investigating an infectious outbreak in African monkeys that were being studied in Denmark.
The first human case of the disease dates back to 1970, in the Democratic Republic of the Congo. The first outbreak in a non-endemic territory occurred in 2003, in the United States.
The disease causes swollen lymph nodes, skin lesions, fever, weakness, and intense headaches and body aches. The mortality rate is estimated at between 1% and 10%, with more severe cases in children and people with reduced immunity.
Human-to-human transmission occurs primarily through exposure to open wounds, scabs, and bodily fluids of infected people. Kissing, hugging, and sexual intercourse can also spread the virus, as can respiratory secretions resulting from close and prolonged interactions.
The incubation period for the virus ranges from 5 to 21 days, with transmissibility being from the onset of symptoms to the disappearance of the skin lesions.
The initial symptoms of Mpox may be similar to those of other diseases, such as measles and syphilis. Therefore, laboratory tests with molecular tests (q-PCR) or genetic sequencing are essential for an accurate diagnosis.
An existing vaccine against smallpox, Imvanex, is also effective against MPXV. In Brazil, priority is given to vaccinating citizens who are at greater risk of developing severe cases of the disease. This is the case for people living with HIV/AIDS, laboratory professionals who work directly with viruses of the Orthopoxvirus genus, and those who have had contact with patients' bodily fluids and secretions. Users of HIV Pre-Exposure Prophylaxis (PrEP) can also get vaccinated.
Since universal vaccination is not recommended, the best way to prevent Mpox is to avoid direct contact with confirmed or suspected cases. If contact is essential, personal items such as clothes, towels and cutlery should not be shared. In addition, it is recommended to wear gloves, masks, aprons and protective glasses.
Check below the list of news with special coverage on the contributions of researchers at the Institute.
MPXV virus particles (in green) adhered to filaments of the Vero cell cytoskeleton. Photo: Debora Ferreira Barreto Vieira
On August 14, 2024, the increase in Mpox cases in the Democratic Republic of the Congo (DRC) and other African countries led the World Health Organization (WHO) to declare, for the second time, a public health emergency of international concern.
The statement followed the recommendation of a committee of independent experts, which pointed to the potential for the outbreak to spread, associated with the rapid spread of a new strain of the mpox virus (MPXV), called clade 1b.
In Brazil, the first case of the variant was confirmed on March 7, 2025, in São Paulo. The patient, a 29-year-old woman, had not visited areas with Mpox outbreaks, but had contact with a family member from RCD.
Prior to the spread of the clade 1b strain, the first emergency declaration occurred in July 2022, when a multinational outbreak caused by MPXV clade 2 was recorded. This emergency ended in May 2023, after a sustained decrease in cases worldwide.
MPXV belongs to the Orthopoxvirus genus, which also includes the pathogens responsible for human and cowpox. It was discovered in 1958, when researchers were investigating an infectious outbreak in African monkeys that were being studied in Denmark.
The first human case of the disease dates back to 1970, in the Democratic Republic of the Congo. The first outbreak in a non-endemic territory occurred in 2003, in the United States.
The disease causes swollen lymph nodes, skin lesions, fever, weakness, and intense headaches and body aches. The mortality rate is estimated at between 1% and 10%, with more severe cases in children and people with reduced immunity.
Human-to-human transmission occurs primarily through exposure to open wounds, scabs, and bodily fluids of infected people. Kissing, hugging, and sexual intercourse can also spread the virus, as can respiratory secretions resulting from close and prolonged interactions.
The incubation period for the virus ranges from 5 to 21 days, with transmissibility being from the onset of symptoms to the disappearance of the skin lesions.
The initial symptoms of Mpox may be similar to those of other diseases, such as measles and syphilis. Therefore, laboratory tests with molecular tests (q-PCR) or genetic sequencing are essential for an accurate diagnosis.
An existing vaccine against smallpox, Imvanex, is also effective against MPXV. In Brazil, priority is given to vaccinating citizens who are at greater risk of developing severe cases of the disease. This is the case for people living with HIV/AIDS, laboratory professionals who work directly with viruses of the Orthopoxvirus genus, and those who have had contact with patients' bodily fluids and secretions. Users of HIV Pre-Exposure Prophylaxis (PrEP) can also get vaccinated.
Since universal vaccination is not recommended, the best way to prevent Mpox is to avoid direct contact with confirmed or suspected cases. If contact is essential, personal items such as clothes, towels and cutlery should not be shared. In addition, it is recommended to wear gloves, masks, aprons and protective glasses.
Check below the list of news with special coverage on the contributions of researchers at the Institute.
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