Colombia has confirmed its first case of a new variant of mpox, specifically clade Ib, marking a significant development in the ongoing global monitoring of the virus. The case was identified in the Antioquia department and reported by the Ministry of Health and Social Protection (MinSalud) in early August 2024. This detection follows heightened surveillance efforts across Latin America after the World Health Organization (WHO) declared the mpox outbreak a public health emergency of international concern in August 2024, primarily due to the spread of clade Ib in Central and East Africa.
The confirmation comes amid growing attention to the evolving epidemiology of mpox, a zoonotic disease caused by the monkeypox virus, which belongs to the Orthopoxvirus genus. While the global outbreak that began in 2022 was predominantly driven by clade IIb and largely affected gay, bisexual, and other men who have sex with men (GBMSM) through close personal contact, the emergence of clade Ib raises new questions about transmission dynamics and potential shifts in clinical presentation. Health authorities in Colombia have emphasized that the risk to the general population remains low, but they are urging vigilance, particularly among individuals with recent travel history to affected regions or close contact with suspected cases.
According to MinSalud, the patient is a male resident of Antioquia who developed symptoms consistent with mpox and sought medical care, leading to laboratory confirmation through polymerase chain reaction (PCR) testing at the National Institute of Health (INS). The case was sequenced and identified as clade Ib, a variant previously associated with sustained human-to-human transmission in the Democratic Republic of the Congo (DRC) and neighboring countries. Colombian health officials have activated contact tracing and monitoring protocols, and the patient is reported to be in stable condition and isolating as per national guidelines.
Although the WHO’s emergency declaration in August 2024 was primarily driven by the rapid spread of clade Ib in Africa, the detection in Colombia represents the first confirmed case of this variant in South America. This development underscores the importance of genomic surveillance and rapid information sharing through platforms like the Global Initiative on Sharing All Influenza Data (GISAID), which has played a critical role in tracking mpox evolution. As of mid-August 2024, over 18,000 suspected and confirmed mpox cases had been reported globally in 2024, with the majority occurring in Africa, according to the WHO’s situational reports.
What is mpox clade Ib and how does it differ from previous strains?
Mpox, formerly known as monkeypox, is a viral disease that can spread from animals to humans and between people. The virus is divided into two main clades: clade I, which is endemic in Central Africa and generally associated with more severe disease, and clade II, found in West Africa and typically linked to milder outcomes. Within these clades, subtypes exist—such as clade Ib, which has emerged as a distinct lineage within clade I and is currently driving transmission in parts of Eastern and Central Africa.
Clade Ib is genetically distinct from the clade IIb variant that caused the global outbreak starting in 2022. Preliminary data suggest that clade Ib may be associated with different epidemiological patterns, including a higher proportion of cases among children and individuals without known high-risk exposures, although research is ongoing. The WHO and the Africa Centres for Disease Control and Prevention (Africa CDC) have noted that clade Ib appears to be spreading efficiently through close contact, including household and sexual transmission, but further studies are needed to determine if it has increased transmissibility or altered virulence compared to earlier strains.
Symptoms of mpox, regardless of clade, typically include fever, headache, muscle aches, swollen lymph nodes, and a characteristic rash that progresses through stages—from macules to papules, vesicles, pustules, and finally scabs. The rash often appears on the face, palms, soles, and genital or perianal areas. Lesions can be painful or itchy and may last two to four weeks. In some cases, complications such as secondary bacterial infections, pneumonia, or encephalitis can occur, particularly in immunocompromised individuals, pregnant women, or young children.
Transmission occurs through direct contact with infectious skin lesions, bodily fluids, or contaminated materials such as bedding or clothing. Respiratory droplets may also play a role in close-range, prolonged face-to-face contact, though airborne spread over long distances is not considered a primary route. Unlike respiratory viruses such as SARS-CoV-2, mpox does not spread efficiently through casual conversation or brief proximity.
Public health response and guidance in Colombia
Following the confirmation of the clade Ib case, MinSalud issued an official statement urging healthcare providers to maintain a high index of suspicion for mpox in patients presenting with compatible symptoms, especially those with recent travel to Central or East Africa or contact with confirmed or suspected cases. The ministry emphasized that diagnostic testing is available through the national public health laboratory network and that all suspected cases should be reported immediately to territorial health authorities.
Colombia’s National Institute of Health has reinforced surveillance at points of entry, including airports and border crossings, and is coordinating with regional health offices in Antioquia and neighboring departments to monitor for additional cases. Contact tracing is underway for the confirmed case, and close contacts are being monitored for symptoms for up to 21 days after exposure, which is the maximum incubation period for mpox.
Vaccination remains a key tool in preventing severe outcomes. The WHO recommends the use of modified vaccinia Ankara (MVA-BN) vaccine, marketed as Jynneos in the United States and Imvamune or Imvanex in Europe, for pre-exposure prophylaxis in high-risk groups and post-exposure vaccination within four days of contact. While Colombia has not launched a mass vaccination campaign, the Ministry of Health has confirmed that limited doses are available for targeted use in outbreak response scenarios, particularly for healthcare workers and close contacts of confirmed cases.
Public health officials continue to stress that the overall risk to the general population remains low. They advise the public to avoid close contact with individuals who have unexplained rashes or symptoms consistent with mpox, to practice good hand hygiene, and to seek medical care promptly if symptoms develop. Stigmatization of affected individuals is discouraged, as it may hinder testing and reporting efforts.
Global context and ongoing concerns
The detection of clade Ib in Colombia adds to a growing list of countries outside Africa that have reported travel-associated or locally acquired cases of this variant. By mid-August 2024, cases linked to clade Ib had been identified in several European nations, including Sweden and Belgium, as well as in Asia, according to data shared by the WHO and GISAID. These instances highlight the interconnected nature of global health security and the importance of rapid detection, sequencing, and information sharing.
Experts caution that while the current risk assessment for the general public remains low, the situation requires continued monitoring. Factors such as waning immunity from smallpox vaccination (which offered cross-protection against orthopoxviruses), increased global travel, and potential changes in viral behavior could influence future transmission patterns. The WHO’s emergency committee has recommended that countries strengthen surveillance, ensure access to diagnostics and vaccines, and engage communities in risk communication without reinforcing stigma.
Research into the biological characteristics of clade Ib is ongoing. Scientists are studying its genetic mutations, particularly in genes associated with virulence and host adaptation, to better understand its transmissibility and clinical impact. Laboratory studies are also evaluating the effectiveness of existing antivirals, such as tecovirimat (TPOXX), which has been used under expanded access protocols during outbreaks, though conclusive data on efficacy remain limited.
As of late August 2024, the WHO continues to coordinate the global response through its incident management system, providing technical guidance, coordinating vaccine equity efforts, and supporting surveillance in affected regions. The next official update on the mpox situation is expected during the WHO’s biweekly disease outbreak news release, with the next scheduled publication set for early September 2024.
For the most reliable and up-to-date information, the public is encouraged to consult official sources such as the World Health Organization’s mpox dashboard, the Pan American Health Organization (PAHO), and Colombia’s Ministry of Health and Social Protection. These platforms provide regular updates on case numbers, guidance documents, and vaccination recommendations.
Understanding emerging infectious disease threats like mpox clade Ib requires sustained investment in public health infrastructure, global cooperation, and clear, evidence-based communication. While the current case in Colombia does not signal an imminent widespread outbreak, it serves as a reminder that vigilance, preparedness, and equitable access to medical countermeasures are essential in safeguarding global health.
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