Emerging infections pose a great threat to public health worldwide. According to the World Health Organization, emerging infections are rising at a rate never seen before, putting every country and every human at risk of illness. Vigilance in recognizing these infections is critical to help control their spread. Practicing clinicians play an integral role in monitoring emerging and re-emerging diseases. Continued development of surveillance systems, rapid diagnostics, rapid therapeutics, and vaccine technologies will go a long way to help in the fight against these emerging infections.
In the recent Pri-Med East conference in Boston, Kalpana Gupta, MD, MPH, Professor of Medicine, Boston University School of Medicine, Boston, MA, gave a talk highlighting the factors associated with emerging infectious diseases and raising awareness among clinicians about them.
Factors associated with emerging infections
The evolution of the pathogen over time has contributed greatly to these emerging infections, making them more infectious, developing the ability to spread in humans, and developing resistance to therapies. Human behavior has also played a role in the rise of these emerging infections. These include population growth, migration from rural to urban areas, international travel, poverty, wars, destructive ecological practices, and loss of immunity.
Emerging Outbreaks Over the Past 100 Years
Influenza
Since the late 19th century, there have been five pandemics related to influenza. Influenza is prone to pandemics due to antigenic drift (in all virus subtypes) and antigenic shift (only influenza A). Medical science has had the following accomplishments in the management of influenza. These include more than 700 drug development programs in planning stages, more than 460 trials reviewed by FDA, 13 COVID-19 treatments currently authorized for emergency use, and two treatments currently approved by FDA for use in Covid 19. Additionally, 4 SARS-CoV-2 Vaccines (EUA and FDA approved) are available, which have been shown to reduce the severity of COVID and COVID deaths. These include the ones from Pfizer, BioNTech, J&J/Janssen, Novavax, and Moderna.
Melioidosis: Bacterial threats
Melioidosis is caused by Burkholderia pseudomalle. This disease is predominant in the tropics and has been found along the Mississippi Gulf Coast. Infection occurs after exposure to soil and water contaminated with the bacteria leading to acute illness (Fever, ulceration, localized pain, pulmonary disease ) and chronic illness (mimics TB).
In 2021, there was reportedly a multi-state outbreak in 4 states in the US. None of the cases had traveled outside the US. 2 cases of melioidosis in Mississippi in 2020, and 2022 indicated B. pseudomallei was endemic on the Gulf Coast as there was no travel outside the US. It is crucial to keep an eye out for this bacterium and be aware of symptoms like fevers, cough, sepsis, nonhealing ulcers, and travel to the Mississippi Gulf Coast.
Monkeypox
Monkeypox is caused by a double-stranded DNA virus belonging to the Poxviridae family. It was first recognized in 1958 in 2 outbreaks of a pox-like illness in research primates and the first human cases reported were in 1970. Currently, the US has a total of 26049 cases of monkeypox with two deaths, whereas the total number of cases globally stands at 70696.
Some of the unique features of the current outbreak are that most men and men who have sex with men that have been infected, greater than 95% of patients have had a rash or enanthem, greater than 65% of patients have only anogenital lesions, Rashes in different stages has been identified on mucosal surfaces and genitalia and monkeypox DNA detected in semen in 29 of 32 men tested.
Issues to consider regarding monkeypox detection are that these rashes may resemble other ulcerative sexually transmitted diseases (STIs). In a patient with genital ulcers or rash, especially if STI testing is negative, monkeypox should be considered. Also, testing needs to be more readily available to diagnose more cases with rapid turnaround time and more access to treatment and vaccination.
Heartland and Bourbon Viruses
In 2012, two cases were reported of a febrile illness that started 5-7 days after a tick bite. Electron microscopy and PCR identified viral particles in the Bunyaviridae family. Since 2017, More than 50 cases have been identified. Symptoms include fever, fatigue, decreased appetite, headache, arthralgia, myalgia, nausea, vomiting, leukopenia, thrombocytopenia, and elevated transaminases.
Poliovirus
Oral poliovirus (OPV) is a live virus vaccine. Vaccine-derived poliovirus (VDPV) can arise when OPV replicates in a community with a low level of vaccination. In upstate New York, the poliovirus vaccine rate in children less than 24 months has decreased from 67% in 2020 to 60% in 2022. Some areas have only 35% vaccine coverage, while national coverage is 93%. Care must be taken as a reduction in vaccine coverage and identification of poliovirus in wastewater can lead to a resurgence of poliovirus infection and paralysis.
Childhood Acute Hepatitis
Childhood Acute Hepatitis was first identified in April 2022, and since then, over 1,000 cases have been identified in multiple countries, mainly in Europe and US. Cases are usually aged less than 16 years, with acute hepatitis, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) >500, and exposure to someone diagnosed with acute hepatitis.
What Can Be Done?
Clinicians should be extra aware of emerging and re-emerging infections. They should know that these infections are circulating, what to look for on presentation, and how to report conditions when identified. Vaccination should be promoted for all patients. The development of new surveillance tools (like wastewater surveillance and artificial intelligence), development of rapid diagnostics, rapid treatments, and rapid vaccine strategies should be focused on.