A recent discovery in Greenville, North Carolina has put public health surveillance techniques in the spotlight: wastewater samples from a local sewage plant have tested positive for Mpox, the virus formerly known as monkeypox, specifically identifying the clade I strain. The samples, collected between late March and early April, point to the potential presence of the virus in the community, even though no clinical Mpox cases have been officially reported so far. Local health officials are now urging healthcare providers to be vigilant for possible symptoms and to quickly report any suspected infections (WRAL; ABC11).
This news is highly significant for Thailand and other countries watching for infectious disease resurgence. Wastewater-based surveillance (WBS), which soared in popularity during the COVID-19 pandemic, allows authorities to detect pathogens shed by infected individuals—often before traditional clinical surveillance picks them up. In the case of Mpox, the detection in sewage means that the virus might already be circulating in the community, possibly among people with mild, pre-symptomatic, or even asymptomatic infection. “The detection of clade I mpox virus in wastewater surveillance tells us the virus is potentially here in our state, even though no cases have been reported and confirmed,” said Dr. Dev Sangvai, Secretary of North Carolina Health and Human Services (WRAL).
Mpox is primarily transmitted through prolonged, close, often skin-to-skin contact, which can occur during sexual activity. The classic symptoms include fever, chills, swollen lymph nodes, and a distinctive rash that can appear on various body parts, including the hands, feet, chest, face, or genitals. While the majority of cases tend to be mild, more severe complications can arise, especially among immunocompromised individuals (CDC).
Why does this matter for Thailand? In recent years, Thailand has invested in disease surveillance systems, but much of the focus has been on clinical reports and border controls. Wastewater-based approaches, highlighted by global research during the COVID-19 era, offer a more comprehensive and early-warning method of detecting emerging infections, especially when traditional testing may miss pre-symptomatic or underreported cases (Systematic Review: PubMed). A 2025 systematic review found the overall Mpox positivity rate in global wastewater studies to be about 22%, with wastewater analysis proving highly effective at identifying community viral presence, sometimes before clinical outbreaks were declared (Systematic Review: PubMed).
Moreover, a recent study utilizing AI-powered robots demonstrated that the concentration of Mpox viral DNA in sewage is closely linked to the number of clinical cases, potentially providing highly accurate forecasts for outbreaks. “Our AI prediction model captured 87% of the data’s variability, making it a powerful tool for tracking and responding to mpox outbreaks,” noted researchers from a 2024 study (Automated WBS Study). These findings bolster the case for integrating WBS into standard public health surveillance—something Thailand can adapt to augment its own monitoring efforts, especially in urban areas or large events where person-to-person transmission risks are higher.
The strain found in Greenville, clade I, is particularly noteworthy because current global Mpox outbreaks have been dominated by clade IIb strains—responsible for most cases outside Africa since 2022. Clade I, commonly found in central Africa, has historically been associated with higher severity and a greater risk of complications (CDC: Types of Monkeypox). The World Health Organization (WHO) recently heightened its alert over the international spread of Mpox, including clade I and newly described clade Ib, due to outbreaks in Central Africa and rising risks in travel hubs (PubMed: Clade Ib Spread). While there is no evidence that the strain found in Greenville originated from Africa, its emergence underlines the need for vigilance, even in countries that have not reported recent clinical cases.
From a historical perspective, Thailand still remembers the global alarm sparked by the 2022-2023 Mpox outbreaks, which disproportionately affected men who have sex with men (MSM) and other high-contact groups (WHO Situation Report). While the outbreaks were eventually contained through targeted vaccination and education, sporadic cases and potential importation events continue to threaten regions with low population immunity. In Thai culture, open conversations about diseases linked to sexuality and skin-to-skin contact can be sensitive – yet the experience of COVID-19 has made many Thais more receptive to proactive health measures and surveillance innovations.
Given the proven performance of wastewater surveillance in rapidly detecting various pathogens—including SARS-CoV-2, influenza, and Mpox—public health leaders in Thailand and Asia should seriously consider expanding WBS programs. Innovative systems, such as those developed in the Netherlands and South Korea, have shown that real-time monitoring can inform smarter, faster interventions, especially when clinical data are delayed or incomplete (Netherlands Study, South Korea Study). Privacy concerns, ethics, and technical capacity must be carefully managed, particularly when targeting specific at-risk communities, but the benefits of early warning are clear.
Looking to the future, the rising threat of zoonotic viruses and emerging infectious diseases means Thailand cannot afford to rely only on traditional surveillance approaches. As Professor Charalambos Kaittalides from the International Society for Infectious Diseases told Public Radio East, “Environmental surveillance through wastewater is a game-changer—it allows us to see the invisible part of the epidemic iceberg, catching viral spread before we see sick patients in clinics” (Public Radio East). While Thailand has not faced a major Mpox epidemic to date, the nation’s role as a tourism hub and logistics center means risks can escalate suddenly, as past dengue and COVID-19 waves have shown.
Practically, what can Thailand do next? Health agencies should prioritize funding pilot WBS studies in Bangkok, Phuket, Chiang Mai, and border provinces, focusing on major wastewater plants and neighborhoods with high traveler traffic or known risk populations. Training local medical staff to recognize and report Mpox symptoms remains essential—remembering that skin rashes, fever, and swollen glands can have many causes, but suspicion should be raised if cases cluster or align with wastewater signals. Equally important is community education: destigmatizing the discussion around infectious diseases and close-contact transmission, so that symptomatic individuals seek care quickly and honestly, regardless of the perceived source.
Finally, for the general Thai public: good personal hygiene, avoiding close skin-to-skin contact with people who have unexplained rashes or flu-like symptoms, and promptly seeking medical attention if symptoms arise are simple but effective steps. As Thailand navigates the post-pandemic world, embracing new tools like wastewater surveillance (in Thai, การเฝ้าระวังผ่านน้ำทิ้ง), alongside traditional approaches, will be crucial to keeping our “บ้านเรา” safe from old and emerging threats alike.
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