Polio Agent Information Sheet

Boston University
Research Occupational Health Program (ROHP)
617-358-7647

Agent

Polio virus is the type species of the Enterovirus genus in the family Picornaviridae. Enteroviruses are transient inhabitants of the gastrointestinal tract, and are stable at an acidic pH. Picornaviruses are small with an RNA genome. There are three poliovirus serotypes (P1, P2, and P3). Immunity to one serotype does not produce immunity to the other serotypes.

Disease/Infection

Poliomyelitis, polioencephalitis

Pathogenicity

Almost 95 percent of infections are asymptomatic. One in 200 infections leads to irreversible paralysis (usually in the legs). Among those paralyzed, 5% to 10% die when their breathing muscles become immobilized.

Polio virus principally affects motor neurons and autonomic neurons. Neuronal destruction is accompanied by an inflammatory infiltrate of polymorphonuclear leukocytes, lymphocytes, and macrophages. The lesions are characteristically distributed throughout the gray matter of the anterior horn of the spinal column and the motor nuclei of the pons and medulla. Clinical symptoms depend on the severity of lesions rather than on their distribution.

• Special Populations at Risk
  Immune deficiency, malnutrition, pregnancy, children

Biosafety Information

Risk Group/BSL
Risk Group 2
Biosafety Level 2 Practices

Modes of Transmission

Host Range/Reservoir
No endogenous reservoir exist in the United States

Symptoms
Polio invades the nervous system, and can cause total paralysis in a matter of hours. The virus enters the body through the mouth and multiplies in the intestine. Initial symptoms of polio include fever, fatigue, headache, vomiting, stiffness in the neck, and pain in the limbs. In a small proportion of cases, the disease causes paralysis, which is often permanent.

Polioencephalitis is rare and generally occurs in infants. Between 25-50% of survivors may develop postpolio syndrome experienced over their remaining life as muscle weakness and extreme fatigue.

Incubation period
9-12 days

Viability
Polio virus is resistant to inactivation by common laboratory disinfectants such as alcohol. The virus is rapidly destroyed by exposure to temperatures of 50°C or more, autoclaving or incineration. It is readily inactivated by dilute solutions of formaldehyde bleach and UV light. 0.5% bleach solution is recommended disinfectant.

Survival Outside Host
Polio virus is very stable at an acidic pH and can remain infectious for long periods of time in food and water.

Information for Lab Workers

Laboratory PPE

Personal protective equipment includes but is not limited to laboratory coats or gowns, disposable gloves, and safety glasses. Face shields may be recommended based on risk assessment.

Containment

BSL-2 practices, containment equipment, and facilities are recommended for all activities utilizing wild polio virus infectious culture fluids, environmental samples, clinical materials, and potentially infectious materials collected for any purpose. Laboratory personnel working with such materials must have documented polio immunization. ABSL-2 practices, containment equipment, and facilities are recommended for studies of virulent viruses in animals.

In Case of Exposure/Disease

• For injuries in the lab which are major medical emergencies (heart attacks, seizures, etc…):
• Medical Campus: call or have a coworker call the Control Center at 617-414–4144.
• Charles River Campus: call or have a coworker call campus security at 617-353-2121.
  You will be referred to or transported to the appropriate health care location by the emergency response team.
• For lab exposures (needle sticks, bite, cut, scratch, splash, etc…) involving animals or infectious agents, or for unexplained symptoms or illness call the ROHP 24/7 hour number (1-617-358-ROHP (7647); or, 8-ROHP (7647) if calling from an on-campus location) to be connected with the BU Research Occupational Health Program (ROHP) medical officer. ROHP will refer you to the appropriate health care location.
• Under any of these scenarios, always inform the physician of your work in the laboratory and the agent(s) that you work with.
• Provide the wallet-size agent ID card to the physician.

Vaccination

If potential exposure, check antibody to Polio.  A positive antibody indicates protection.
IPV – Inactivated polio vaccine recommended if no antibody.
OPV – Oral Polio vaccine- No longer distributed in the United States

Information for First Responders/Medical Personnel

Public Health Issues

Person to person transmission can occur through fecal oral route and via infected feces and body fluids. Contact precautions should be used.

Diagnosis/Surveillance

Polioviruses usually can be isolated from throat secretions in the first week of illness and from feces, often for several weeks. In the absence of a viral isolate, the diagnosis of poliovirus infection can be established serologically by testing paired acute and convalescent sera for neutralizing antibodies to each of the three poliovirus serotypes. Serologic tests cannot distinguish between wild-type virus and vaccine virus infection. These viruses can be detected by PCR.

First Aid/Post Exposure Prophylaxis

Perform one of the following actions:

Treatment

There is no specific treatment for polio. Persons infected with polio need supportive therapy, such as bed rest and fluids. Severe paralytic disease impacting diaphragm may require mechanical ventilation.

References

CDC – Polio Fact sheet http://www.cdc.gov/vaccines/parents/diseases/child/polio.html 

Biosafety in Microbiological and Biomedical Laboratories (BMBL) 5th Edition. US Government Printing Office, Washington, 2007.

Willey, Microbiology 7^th edition, McGraw Hill, 2008

Mandell, Douglas, and Bennett’s Principles and practices of Infectious Disease 6^th Edition, Elsevier, 2005.

WHO Action Plan for laboratory containment of wild polio viruses, second edition –   https://apps.who.int/iris/bitstream/handle/10665/68205/WHO_V-B_03.11_eng.pdf

Pallansch, M.A. & Oberste, M.S. & Lindsay Whitton, J. (2013). Enteroviruses: Polioviruses, coxsackieviruses, echoviruses, and newer enteroviruses. Fields Virology. 490-530.

Revised: 5/13/19