Argentina Reports First Local Mpox Case – Buenos Aires

Argentina has confirmed its first case of locally acquired mpox clade Ib in Buenos Aires, raising concerns about potential community transmission of this variant. The case involves a man with no recent travel history who reported multiple sexual contacts, including with travelers, prior to symptom onset. Health officials are conducting contact tracing and monitoring the situation closely.

Understanding Mpox Clade Ib

Mpox, formerly known as monkeypox, is a viral infection that can cause a range of symptoms, including a characteristic rash, fever, headache, muscle aches, and swollen lymph nodes. The virus has two main clades, or genetic branches: clade IIb and clade Ib. The recent outbreak that gained global attention in May 2022 was primarily driven by clade IIb. However, clade Ib has been characterized by Argentina’s Ministry of Health as being more contagious and potentially more severe than previous strains. This distinction is crucial, as it suggests a potentially different transmission dynamic and clinical course.

The first confirmed case in Argentina occurred in a 31-year-old man residing in Buenos Aires, with symptoms beginning on February 24, 2026, according to Beacon Bio. The patient presented with a rash, fever, headache, myalgia (muscle pain), lymphadenopathy (swollen lymph nodes), and anorectal pain.

Transmission Dynamics and Risk Factors

The emergence of locally acquired clade Ib in Buenos Aires is particularly noteworthy as the individual had no recent international travel history. This indicates the virus is now circulating within the local population. The reported sexual contacts, including those with travelers, suggest a key transmission pathway. Mpox can spread through close, intimate contact with an infected person or with materials contaminated with the virus, such as clothing, bedding, or surfaces. Sexual contact, particularly among men who have sex with men, has been identified as a significant route of transmission in the current outbreak, mirroring patterns seen in the 2022 global outbreak, which saw over 100,000 confirmed cases across 122 countries. Vax Before Travel notes that Buenos Aires, a major South American tourism hub, welcomed approximately 1.5 million foreign visitors last year, potentially contributing to the introduction and spread of the virus.

Argentina’s Response and Global Context

Argentine health authorities are taking steps to contain the spread of clade Ib. These measures include contact tracing, recommendations for 21 days of follow-up monitoring for contacts, and urging healthcare authorities to strengthen surveillance. The Ministry of Health is likewise emphasizing the importance of proper isolation until lesions have scabbed over and ensuring healthcare workers have appropriate personal protective equipment (PPE). This aligns with recommendations from the World Health Organization (WHO) regarding infection control practices for mpox.

Prior to this recent case, Argentina had reported approximately 1,129 confirmed cases and two deaths between 2022 and early 2023. As of 2026, eight countries in the Americas have reported a total of 172 mpox cases, with no deaths recorded to date. The confirmation of local transmission in Argentina signals a potential shift in the epidemiological landscape of mpox in the region.

What Does This Mean for Travelers?

While the current case is locally acquired, the connection to travelers highlights the ongoing risk of international spread. Individuals traveling to Buenos Aires, or other areas where mpox is circulating, should be aware of the potential for exposure. The Centers for Disease Control and Prevention (CDC) provides updated travel health notices and recommendations on its website: https://www.cdc.gov/. Practicing safe sexual behaviors, avoiding close contact with individuals exhibiting symptoms, and adhering to local public health guidelines are essential preventative measures.

Looking Ahead: Surveillance and Monitoring

The Argentine Ministry of Health is prioritizing enhanced surveillance to detect and respond to any further cases of clade Ib. This includes increased testing capacity, improved data collection, and ongoing monitoring of transmission patterns. The situation is evolving, and public health officials will continue to assess the risk and adjust their strategies accordingly. Further research is needed to fully understand the characteristics of clade Ib, including its transmissibility, severity, and response to available treatments and vaccines. The ongoing monitoring of cases and genomic sequencing will be crucial in tracking the evolution of the virus and informing public health interventions.

The patient in Buenos Aires is currently receiving outpatient treatment and is reportedly recovering. Contact tracing efforts are underway to identify and monitor individuals who may have been exposed. The success of these efforts will be critical in preventing further spread of the virus within the community.