>>Learn about the possible causes of emergences and re-emergences of infectious diseases and how diseases spread.
>>Understand when to have a high index of suspicion for enterovirus D68, which can present with many different signs and symptoms.
>>Identify ways EMS systems can adapt during an outbreak to ensure provider safety while also still protecting and treating the community.
>>Emerging disease: A disease not previously recognized.
>>Fomites: Any objects, including an EMS worker’s uniform, that can be contaminated by infectious pathogens and can play a role in transmission of the pathogen.
>>Herd immunity: Also known as social immunity or herd effect, it occurs when the bulk of the people in a population are immune, thereby disrupting the spread of a disease to non-immune people. Essentially, the immune people act as a buffer to prevent the disease from spreading through the community.
>>Re-emerging or resurging disease: A disease that’s been around, sometimes known for centuries, and has come back in a new form or in locations where it hasn’t been previously seen.10
>>Zoonoses: Animal diseases that are spread to humans. More than 70% of emerging diseases are zoonotic.4
Since Ebola, measles, West Nile virus and enterovirus D68 hit the headlines in 2014, there’s been a renewed focus on emerging disease as well as re-emerging or resurging disease. Even rubella, also known as “German measles,” is making its comeback.
There are many reasons, some not completely understood, for the re-emergence of some diseases. Some cases, however, are associated with the refusal to vaccinate children as a result of a fraudulent link between autism and vaccines; we now know the researcher, Andrew Wakefield, falsified some of the facts of his research published in The Lancet in 1998.1 The Lancet retracted the article in 2010, after over a decade of damage was done.2 In addition to falsifying data and results, Wakefield didn’t disclose that he received funding from attorneys who represented families with lawsuits against vaccine-producing companies.3
This isn’t the only reason some parents may choose not to vaccinate their children; however, the fraudulent link did a great deal of damage as vaccination rates plummeted in the United States and the United Kingdom following its publication. During the decade that passed, measles once again became endemic in England and Wales as vaccination rates dropped to below 80%, well below the 95% necessary for herd immunity.1
Despite this fraud being exposed, and Wakefield and his senior research advisor losing their medical licenses, many parents today still believe there’s a strong link between vaccines (in particular the measles, mumps and rubella vaccine) and autism as well as other childhood developmental disorders. This misconception endures despite evidence that the prevalence of autism went up while vaccination rates fell.
Earlier this year, the first child in 28 years died of diphtheria in Spain. The parents of the 6-year-old boy stated they were “tricked” by the misinformation about vaccines. The Wakefield fraud may go down as one of the most serious and damaging frauds in medical history.3
Causes of resurgence and re-emergence of disease aren’t limited to vaccination. Like emerging new diseases, causes of the resurgence of many communicable diseases include the spread of human habitation and development of land, and international travel that leads to importation of disease, with other causes remaining unknown.4 No matter what the cause, EMS workers now have to be more informed regarding communicable diseases than ever before.
EMS professionals are the only members of the healthcare community who have intimate access to the patient’s home, living conditions, family and friends at the time the patient initially presents to the healthcare community with their disease process. This brings unusual hazards for EMS workers as it places them in a “high-risk zone,” but it also brings responsibilities that may not have been previously recognized.
How Disease Spreads
Diseases are ever-present and threaten the health of populations of people. A great many of these diseases are zoonoses that spread from animal to people. Severe acute respiratory syndrome (SARS), which led to a worldwide epidemic and more notably an outbreak in Toronto, Canada, started when the virus spread from bats to civet cats and then to people in 2002.4 While it’s known that most people who have caught the coronavirus that causes Middle East respiratory syndrome (MERS) were infected by other humans, the disease is also known to have jumped from animals to humans and has been isolated in camels.
How zoonotic diseases jump species is of great interest to researchers. Sometimes the disease is the result of an insect bite, such as it is with plague, which is usually caused by a flea bite. The flea bites the host animal such as a rat or prairie dog, infecting the flea. When the bacteria clogs its foregut, the flea feels constantly hungry, causing it to bite more frequently. When the flea bites, it expels the bacteria. When it does this into a human, it can cause a plague.
Sometimes zoonotic diseases infect humans when one handles infected animal flesh or is bitten by the infected animal, such as can be the case with Ebola. The source can be much more elusive than direct transmission. For example, it took a great deal of investigation to discover that bats transmitted the Nipah virus to people via date palm sap.4 This virus has caused a number of deaths in Bangladesh since 2011 because the date palm sap has been used to make a popular local drink.4
A familial generation of humans is slightly more than 20 years, whereas a microbial generation may occur within minutes. This is important to keep in mind because when a microbial generation replicates, mutations can occur; some of these mutations are adaptations to human interventions such as the use of antimicrobials. This rapid replication and mutation gives microbes the ability to adapt to and bypass our interventions.4
Enterovirus D68 Re-Emerges
An outbreak of enterovirus D68 (EV-D68) is an example of one disease that we really don’t know much about—we don’t know its natural reservoir or its ecology. It was first isolated and recognized in California in 1962. Since then, the disease has received little attention.
Between 1970 and 2005 there were 36 cases of EV-D68 reported to the CDC.5 It exploded back on the scene in 2014, a year that saw outbreaks of many diseases of concern. In 2014 alone, there were over 1,100 cases reported to the CDC, with other countries in Europe and Asia also reporting unusual increases in cases.6–8
EV-D68 is a member of the enterovirus D (EV-D) species. There are five EV-D serotypes identified, three of which cause disease in humans: EV-D70 has been associated with acute hemorrhagic conjunctivitis, EV-D94 causes acute flaccid paralysis, and EV-D68 causes severe respiratory illness and flaccid paralysis. It should be noted that poliomyelitis, which appeared in the late-1800s and early to mid-1900s, was the first human enterovirus discovered.5 This is of concern because an enterovirus such as EV-D68 may come to occupy the space in viral ecology that has been left vacant by the eradication of poliovirus in much of the world.7
EV-D68 is an important respiratory pathogen that can cause respiratory disease that ranges from mild to severe and, in some cases, is fatal. The disease has disproportionately affected children.
Pathophysiology: Not much is known about how EV-D68 causes disease in humans. There are no reliable animal models upon which we can make many assertions regarding its pathogenesis. We do know, however, that the virus shares some biological characteristics with rhinovirus, which may explain its affinity for the respiratory tract.6 Like rhinovirus, and unlike other EV-D viruses, EV-D68 shows preference for growth in the nose where the temperature is approximately 33 degrees C (91.4 degrees F).5 EV-D68 also is thought to replicate in the respiratory tract.8
Clinical significance: EV-D68 has been associated with significant respiratory illnesses. Studies suggest that those with pre-existing respiratory condition such as asthma or other wheezing illness are most likely to develop a severe infection.6 Reports on patient outcomes throughout the world also suggest that those with severe underlying disease may be more likely to die from EV-D68 infection than those who don’t.6,8
Of great concern is that EV-D68 isn’t exclusively a respiratory disease. A fatal case of meningomyeloencephalitis in New York tested positive for EV-D68. There’s also evidence that EV-D68 may also be associated with a cluster of children in Colorado who exhibited symptoms of acute polio-like flaccid paralysis and cranial nerve dysfunction.8
In short, the worldwide re-emergence of EV-D68 has demonstrated that the disease, so rarely reported before, is capable of a wide range of respiratory and other symptoms. We have a great deal to learn about this virus, its pathogenesis, and what it’s capable of.
Assessment, precautions and treatment: We don’t have a complete understanding of how EV-D68 is transmitted. Most enteroviruses are spread in a fecal-oral manner; some literature suggests that it’s also spread through close respiratory contact.5 It’s recommended that basic rules for droplet and contact precautions should be used during contact with a patient who’s believed to have a seasonal respiratory illness.5,7
Unfortunately, there’s not much that can be done in the prehospital setting to detect EV-D68. Providers should maintain a high index of suspicion when cases are reported and when faced with severe respiratory illness with neurological complications such as acute flaccid paralysis and cranial nerve dysfunction.
There’s currently no vaccine or antiviral drug with which we can treat EV-D68, therefore treatment is currently supportive.
Adapting EMS During an Outbreak
When faced with the outbreak of a communicable disease within the community, it’s important to have policies in place that protect the community, EMS and hospital systems, while simultaneously seeing to continuity of operations. Many lessons can be gleaned from the SARS outbreak in Toronto as well as the Ebola outbreak in West Africa and the cases that appeared in the U.S.
When SARS struck Toronto, Canada’s largest and busiest EMS system, there were 1,166 potential exposures for the city’s 850 paramedics, and over half of the paramedics ended up on 10-day home quarantine.11 To sustain optimal functioning, the following three measures were instituted:11
- EMS headquarters was closed to frontline staff;
- Before entering headquarters or operational areas, staff had to be screened for SARS-like symptoms; and
- Paramedics had to self-evaluate for symptoms of SARS-like illness before their shift and were instructed to stop working and report to a medical support center if symptoms developed.
Additionally, EMS agencies would need a plan to deal with accreditation and other certification issues without potentially ill EMS workers infecting other agency personnel. The agency would need the authority (built into contracts with private EMS as necessary) to either override attendance policies of the private EMS providers or to require them to have a contingency attendance policy that covers outbreaks. This assists with removing the fear that providers may have in calling off sick (such as a write-up) and keeps potentially uninformed supervisors and other administrators from decreasing the EMS workforce through punitive actions (suspensions or termination).
Other lessons learned from Ebola and other outbreaks:
- Instituting “no touch” policies assisted in the limitation of the spread of Ebola. This policy should be followed during the outbreak of any highly contagious disease and means that providers should minimize touch of coworkers and non-patients throughout the shift.
- Requiring all EMS personnel to wear specific equipment during patient contact and to increase the equipment worn with more invasive procedures.
- Keeping a distance of greater than 3 feet while conducting patient interviews.
- Keeping the provider’s hands in front of them, and out of pockets, at all times.
- Walking backward on scene is prohibited in order to prevent infection by fomites.
- ED assessment can take place outside of the ED or reception area.
If recent occurrences of infections of emerging and re-emerging infectious diseases are any indication, it’s crucial that EMS, as front-line healthcare providers, must be informed about communicable diseases. There are some lessons learned from the limited experiences we have regarding widespread outbreaks, and we hope that in the future more knowledge will be contributed concerning the adaptation of EMS systems to future outbreaks.
1. Godlee F, Smith J, Marcovitch H. Wakefield’s article linking MMR vaccine and autism was fraudulent. BMJ. 2011;342:c7452.
2. Editors. Retraction-Ileal-lymphoid-nodular hyperplasia, nonspecific colitis, and pervasive developmental disorder in children. Lancet. 2010;375(9713):445.
3. Rao TS, Andrade C. The MMR vaccine and autism: Sensation, refutation, retraction, and fraud. Indian J Psychiatry. 2011;53(2):95–96.
4. Fauci AS. Emerging and reemerging infectious diseases: The perpetual challenge. Acad Med. 2005;80(12):1079–1085.
5. Petherick A. MERS-CoV: In search of answers. Lancet. 2013;381(9883):2069.
6. Foster CB, Friedman N, Carl J, et al. Enterovirus D68: A clinically important respiratory enterovirus. Cleve Clin J Med. 2015;82(1):26–31.
7. Imamura T, Oshitani H. Global reemergence of enterovirus D68 as an important pathogen for acute respiratory infections. Rev Med Virol. 2015;25(2):102–114.
8. Enterovirus D68: The unexpected guest. Lancet Infect Dis. 2014;14(11):1023.
9. Reiche J, Böttcher S, Diedrich S, et al. Low-level circulation of enterovirus D68-associated acute respiratory infections, Germany, 2014. Emerg Infect Dis. 2015;21(5):837–841.
10. Messacar K, Schreiner TL, Maloney JA, et al. A cluster of acute flaccid paralysis and cranial nerve dysfunction temporally associated with an outbreak of enterovirus D68 in children in Colorado, USA. Lancet. 2015;385(9978):1662–1671.
11. Silverman A, Simor A, Loutfy MR. Toronto Emergency Medical Services and SARS. Emerg Infect Dis. 2004;10(9):1688–1689.