First Locally Acquired Case of Mpox Clade Ib Reported in Buenos Aires, Argentina

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

Details of the Case

According to Argentine health authorities, the case was reported on March 16, 2026, in report #9. The patient is currently recovering and receiving outpatient treatment. He reported having sexual contact with several partners, some of whom had recently traveled internationally, before experiencing symptoms Vax-Before-Travel.

Mpox Clade Ib: Increased Transmissibility and Severity

The Argentine Ministry of Health has characterized clade Ib as being more transmissible and potentially more severe than previous strains of the mpox virus Vax-Before-Travel. This development underscores the virus’s ability to establish transmission chains through sexual networks involving international travelers.

Mpox in Argentina: A Historical Overview

Between 2022 and early 2023, Argentina reported approximately 1,129 confirmed cases of mpox and two deaths. As of 2026, eight countries in the Americas have reported a total of 172 mpox cases, with no deaths recorded to date Vax-Before-Travel.

Mpox Transmission and Risk Factors

Mpox, formerly known as monkeypox, is a zoonotic viral disease caused by the monkeypox virus. The virus can be transmitted through close contact with lesions, body fluids, respiratory droplets, and contaminated materials. Recent outbreaks have shown a pattern of spread among sexual networks, particularly among men who have sex with men ScienceDirect and PubMed. Unprotected sexual contact has been identified as a significant risk factor PubMed.

Public Health Recommendations

In response to the locally acquired case, Argentina’s Ministry of Health is urging health authorities to strengthen surveillance, ensure proper isolation of cases until lesions have scabbed over, and provide healthcare workers with appropriate personal protective equipment Vax-Before-Travel. Contact tracing is underway, with recommendations for 21 days of follow-up monitoring.

Mpox in Women

While mpox has primarily affected men, cases in women have been reported. A study conducted in Buenos Aires between June 2022 and February 2023 found that among 214 positive cases, only 3 (1%) were female PubMed. These cases also reported unprotected sexual intercourse as a risk factor.

Looking Ahead

The confirmation of a locally acquired mpox clade Ib case in Buenos Aires highlights the ongoing need for vigilance and public health measures to prevent further spread. Continued surveillance, rapid contact tracing, and awareness campaigns are crucial to mitigating the risk of community transmission.