Re-emerging Diseases and the Need for Diagnostic Readiness

Across the U.S., infectious diseases once thought to be largely controlled are returning. Measles outbreaks are increasing. Tuberculosis continues to challenge public health systems. Pertussis and other vaccine-preventable infections have reappeared in communities where clinicians rarely expected to encounter them.

Public conversations about these diseases often focus on vaccination rates, treatment protocols or public health policy. Those discussions matter—but they miss a critical point: diagnosis is the frontline of outbreak detection.

Without rapid, accurate laboratory diagnosis, clinicians cannot confirm cases, public health officials cannot track transmission and communities cannot mount effective responses. Every  outbreak begins as a diagnostic question: what is making this patient sick? Medical laboratory and public health professionals—often working behind the scenes—play a decisive role in identifying emerging and re-emerging pathogens—generating the data that drive modern medicine.

Research consistently shows that the majority of clinical decisions rely on laboratory data. Every confirmed case of measles, tuberculosis or other infectious disease begins with the work of laboratory professionals who process specimens, perform tests, validate results and communicate findings. Yet, even within health care systems, many people underestimate how central laboratories are to outbreak response.

Medical laboratory professionals (MLPs):

• Detect pathogens using culture, molecular assays, antigen testing and serology.
• Confirm unusual or unexpected diagnoses.
• Alert clinicians and infection prevention teams when dangerous pathogens appear.
• Provide surveillance data that guide local, state and national public health actions.

When laboratory systems function well, outbreaks can be contained early. When diagnostic systems falter, infections spread silently. Now, the re-emergence of infectious diseases highlights an urgent issue in the U.S.: the nation’s diagnostic readiness may not be keeping pace with the return of diseases that require rapid laboratory recognition. Workforce shortages, aging infrastructure and declining exposure to certain diseases threaten the diagnostic preparedness needed to detect outbreaks early, and we must confront these challenges.

Risk: The Return of “Old” Infectious Diseases

The U.S. eliminated endemic measles transmission in 2000. However, recent years have seen repeated outbreaks linked to declining vaccination coverage and international travel. Similarly, tuberculosis remains a persistent public health threat, particularly in vulnerable populations and areas with limited health care access.

These diseases present a paradox for diagnostic systems. Many clinicians trained in recent decades have limited firsthand experience diagnosing illnesses that became rare in the U.S. following widespread vaccination campaigns—e.g., measles, which can initially resemble other viral respiratory infections; polio; tuberculosis, which requires specialized laboratory testing and biosafety practices; and pertussis, which often presents atypically in vaccinated adults. The same challenges affect laboratories. Staff turnover, workforce shortages and changing test menus can reduce institutional familiarity with diseases that once required routine testing.

Furthermore, emerging zoonotic infections, such as Nipah virus or Crimean-Congo hemorrhagic fever, may not be immediately recognized by clinicians, and across the board, delayed or missed diagnoses allow transmission chains to expand before public health interventions even begin.

Mitigation: Diagnostic Readiness

Reacquiring capabilities that may have faded over time requires comprehensive understanding and execution of diagnostic readiness that extend beyond simply having laboratory tests available. It requires a coordinated system that integrates clinical awareness, laboratory capacity and public health infrastructure.

Key elements include:

1. Clinical Recognition—Physicians and advanced practice providers must consider re-emerging diseases in their differential diagnoses. If clinicians do not suspect measles or tuberculosis, they may never order the appropriate tests.
2. Laboratory Expertise—Laboratories must maintain the technical expertise needed to perform specialized testing and recognize unusual results. Experienced microbiologists often identify patterns that automated systems might miss.
3. Diagnostic Infrastructure—Hospitals and reference laboratories require modern instrumentation, validated assays and supply chain stability to perform timely testing.
4. Public Health Laboratory Networks—State and federal laboratories confirm diagnoses, perform genomic surveillance and coordinate outbreak investigations.

Diagnostic readiness fails when any of these components weakens.

Risk: Laboratory Workforce Shortages 

Recent statements from the Centers for Disease Control and Prevention (CDC) regarding the temporary pause and review of select infectious disease testing should prompt us to look beyond the immediate situation and examine a deeper, ongoing vulnerability in our system—diagnostic workforce capacity. While the CDC has emphasized that this action reflects a commitment to maintaining high-quality laboratory standards, it also underscores how much our national diagnostic infrastructure depends on a relatively small, highly trained workforce and strategies to maintain and support that workforce. When reference testing is interrupted—even briefly—it can create ripple effects across clinical care, public health surveillance and outbreak response, particularly for low-frequency but high-impact pathogens, such as rabies and mpox.

This moment reinforces what many in laboratory medicine have recognized for years, diagnostic readiness is not just about platforms or assays—it’s about people. Clinical microbiologists and laboratory professionals sit at the intersection of laboratory science and clinical medicine, serving as diagnostic stewards in many health care systems. They are critical to ensuring the right tests are ordered, results are accurately interpreted and emerging threats are recognized early. These skills do not develop overnight; they require sustained education, hands-on training and real-world experience.

Unfortunately, we continue to face a shrinking workforce pipeline. Several trends have raised concern among health care leaders. Retirees outpace new laboratory science disciplines. Ongoing training programs are declining. Clinical microbiology expertise is increasingly concentrated to fewer specialty labs, and overall burnout and staffing shortages continue to affect hospital and public health laboratories nationwide. These challenges emerged long before the COVID-19 pandemic, but the pandemic exposed how fragile diagnostic capacity can become under pressure, and many systems still struggle to maintain staffing levels. Collectively, workforce shortages are a major threat to diagnostic preparedness, and re‑emerging diseases will only add to the strain.

Mitigation: Expanding the Laboratory Workforce

As infectious diseases re-emerge and testing complexity grows, strengthening and investing in the laboratory workforce is essential to maintaining the diagnostic readiness on which our health care system depends. Health care systems must support training programs for medical laboratory professionals at all levels, including clinical microbiologists and molecular diagnostics specialists. Workforce pipelines must grow to replace retiring professionals and meet future diagnostic demands.

It is critical to avoid short-term solutions, such as on-the-job training, that, unfortunately, involve lowering personnel standards without meeting educational and internship requirements. Health care systems, public health systems, accrediting bodies, professional organizations and others involved in the laboratory workforce must embrace long-term solutions to attract, recruit and retain MLPs.

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The ASM-WSU Microbiology Certificate Program offers the required education and training needed to work in a Clinical Microbiology laboratory.

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Risk: Aging Laboratory Infrastructure

Aging infrastructure in medical and public health laboratories is an increasingly critical challenge, as many facilities rely on outdated equipment, legacy information systems and physical spaces not designed for modern testing demands. This limits surge capacity during outbreaks, slows turnaround times and increases the risk of errors, biosafety gaps and workforce strain. In an era of emerging infectious diseases and advanced diagnostics, underinvestment in laboratory modernization undermines timely detection, data integration and coordinated public health response, ultimately weakening the broader health care system’s ability to protect communities.

Mitigation: Investing in Laboratory Infrastructure and Supporting Public Health Laboratory Networks

Equipping hospital and public health laboratories to function effectively requires sustained investment in 4 foundational areas:

1. Optimized network of diagnostic services, including, but not limited to, high-throughput molecular testing platforms, rapid pathogen detection systems and genomic sequencing capabilities.
2. Highly trained workforce.
3. Robust data and informatics systems.
4. Updated physical infrastructure.

Collectively, these tools improve detection speed, provide valuable epidemiologic insights and ensure laboratories can handle both routine demands and surge capacity.

Sustained federal investments—most notably the Centers for Disease Control and Prevention Public Health Infrastructure Grant program, which has allocated more than $5 billion toward workforce, data modernization and foundational capabilities—demonstrate both the scale of need and the feasibility of action. Additional support through programs like the Epidemiology and Laboratory Capacity (ELC) cooperative agreements, alongside funding from National Institutes of Health and Biomedical Advanced Research and Development Authority, further underscores the essentiality of laboratory systems to the national infrastructure.

However, we must look beyond funding to sustainability if we are to adequately equip laboratories to be effective. Laboratory systems are too often financed in a reactive, crisis-driven cycle, leaving them underprepared between emergencies. Stable, long-term investment from federal, state and health care system sources, combined with modernized reimbursement models and public–private partnerships, are critical to break this cycle. Public health laboratories serve as the backbone of national disease surveillance. Sustained funding ensures they can confirm cases, monitor outbreaks and support clinical laboratories. Without it, laboratories will continue to face aging infrastructure, workforce shortages and fragmented data systems—conditions that inevitably lead to delayed diagnoses, increased health care costs and weakened public health responses when it matters most.

The Cost of Missed Diagnoses

On the front end, the cost of investing in laboratory infrastructure and supporting public health laboratory networks may seem high, but the cost of missed diagnoses is much higher. Delayed diagnosis does not simply affect individual patients—it can escalate into broader public health failures, including unrecognized transmission in health care settings, outbreaks in schools or communities, increased health care costs due to delayed treatment and loss of public trust in health systems. 

Aging laboratory infrastructure is not just a technical limitation—it has measurable downstream clinical, economic, and public health consequences. When laboratories lack modern diagnostic platforms, data systems or surge capacity, delays in detection cascade rapidly into missed opportunities for containment. For highly transmissible diseases like measles, even a short delay can have exponential consequences. Evidence shows that each measles case in the U.S. can cost roughly $43,000 on average, with total outbreak costs reaching hundreds of thousands to millions of dollars, including an estimated $244,000 just to initiate a response and ~$16,000 for each additional case.

In short, underinvestment in laboratory and public health infrastructure represents a false economy: delays in diagnosis and response lead to more advanced disease, higher treatment costs and expanded outbreak control efforts—ultimately costing health systems and society far more than timely upfront investment..

Looking Ahead

Infectious diseases evolve constantly. Pathogens cross borders, adapt to new hosts and exploit weaknesses in health systems. The COVID-19 pandemic demonstrated how critical diagnostic capacity is during a public health emergency. Early in the pandemic, delays in testing slowed case detection and complicated public health responses. As laboratories expanded molecular testing and built new diagnostic networks, the nation’s ability to track infections improved dramatically. The same lesson applies to re-emerging diseases.

Rapid diagnostics allow public health officials to identify cases quickly, initiate contact tracing, implement infection control measures and monitor transmission patterns, but when diagnostics lag, outbreaks grow. Even diseases that once seemed under control can return when conditions allow. Clinicians and laboratory professionals must remain vigilant for diseases that may appear uncommon today but could become more prevalent tomorrow, and addressing these risks requires coordinated investment across health care systems, academic institutions and public health agencies.

The U.S. has built sophisticated diagnostic networks over decades, but maintaining those systems requires sustained attention and investment. Health care leaders, policymakers and the public must recognize the professionals who stand on the diagnostic frontline. Continued education and cross-disciplinary collaboration play critical roles in maintaining readiness. 

The next outbreak will begin with a single patient—and a laboratory test. Whether that test is ordered, performed and interpreted quickly may determine whether a local infection becomes a national or worldwide crisis. Laboratory professionals must be a part of the national and global equation!