Infection Control Today - 11/2003: Protecting Healthcare Staff

November 1, 2003

Protecting Healthcare Staff From Todays Emerging Infectious Diseases

Protecting Healthcare Staff
From Todays Emerging Infectious Diseases

By Tina Brooks

Healthcare workers (HCWs) face a wide range of hazardson the job, including emerging infectious diseases such as severe acuterespiratory syndrome (SARS), monkeypox and West Nile virus (WNV). It ispossible, however, to prevent or reduce HCWs exposure to todays infectiousthreats.

Stephen S. Morse, PhD, associate professor of the Center for Public HealthPreparedness at the Mailman School of Public Health of Columbia University inNew York says, I think one of the most important things is for people, bothin the professional community and also the public at large, to be well andaccurately informed.


A clearer understanding of SARS has evolved since the appearance of thiscoronavirus in 2002. The severity of the illness is variable, ranging from mildillness to death. The Centers for Disease Control and Prevention (CDC) reportsthat the incubation period for SARS is two to seven days; however, isolated reports have suggested as long as 10 days.1 The illnessbegins with a fever greater than 100.4 degrees F (>38.0 degrees C). Othersymptoms may include headache, muscle aches, cough, shortness of breath anddifficulty breathing.2 Currently, no treatment beyond good intensive and supportive care has been shown to improve prognosis.3

SARS appears to spread from person to person, with cases resulting fromdirect contact with an infected person and household contacts. Infections among HCWs have been a common feature of SARS since its emergence.The majority of these infections have occurred in locations whereinfection-control precautions either had not been instituted or had been instituted but were not followed.4

John Sinnott, MD, director of the Florida Disease Institute in Tampa says,SARS is highly contagious in the hospital setting and probably undergoesamplification. In other words, HCWs are more easily infected than the generalpopulation. If you look at the patients of SARS, an astounding percentage is hospitalworkers.

When caring for suspected or known SARS patients, HCWs should be trained inthe correct use and removal of appropriate personal protection equipment (PPE),including protective gowns, gloves, N95 respirators and eye protection.5Although 11 HCWs in Toronto had worn the recommended PPE each time they entereda patients room, they were infected with SARS. Interviews with the infectedHCWs revealed that PPE had not been fit tested prior to use and an understandingof the correct order of removal of PPE varied among the workers.6

Its clear that with SARS there were some rather high-risk types ofoccupational settings, respiratory therapy and intubation, for example, Morsesays.

Putting tubes or other types of invasive procedures in the respiratorytract, which for obvious reasons, increase HCWs risks more than the emergencyroom.

If there is a potential for exposure to blood or other infectious materials,Occupational Safety and Health Administration (OSHA) regulations state that HCWsmust use PPE in accordance with its Bloodborne Pathogens Standard.7

The housekeeping and environmental services department personnel also shoulduse PPE as required for contact and airborne precautions as long as the patientis in the room. Daily cleaning should include horizontal surfaces (e.g.,over-bed tables and nightstands), surfaces that are frequently touched bypatients and healthcare personnel (e.g., bed rails, phone), and lavatoryfacilities.8 While terminal cleaning should include aforementioned surfacesdescribed above plus soiled vertical surfaces, frequently touched surfaces(e.g., light cords and switches, door knobs) and durable patient equipment(e.g., bed, night stand, over-bed table, wheelchair, commode).9 The CDCrecommends the use of any Environmental Protection Agency (EPA)-registeredhospital detergent-disinfectant for environmental sanitation.


Although discovered in laboratory monkeys in 1958, monkeypox was not reportedin humans until 1970. Recent investigations implicated a shipment of animalsfrom Ghana as the probable source of introduction of the virus into the UnitedStates. It was an unusual event of imported animals in the wrong ecosystems,Sinnott says. It is unclear if monkeypox will arise again.

The signs and symptoms of monkeypox in humans are like those of smallpox, butmilder. Approximately 12 days after infection with this orthopoxvirus,individuals often experience a fever, headache, muscle aches, backache andswollen lymph nodes.10 One to three days after the start of fever, a rash thatdevelops into raised bumps filled with fluid. The bumps eventually scab over andfall off. The illness lasts from two to four weeks. Smallpox vaccination hasbeen reported to reduce the risk of monkeypox infection.

The virus is typically transmitted to humans by contact with an infectedanimal. Monkeypox, which is less infectious than smallpox, can also be spreadfrom person to person. Direct contact with infected human body fluids or withvirus-contaminated objects, such as bedding or clothing, can spread the virus aswell. Sinnott says Thus far in the United States we havent seen anyperson-toperson transmission, but that potential is there.

Transmission of monkeypox within hospitals has occurred.11 Similar to SARS, acombination of standard, contact and droplet precautions should be applied. Housekeeping should be careful when handling soiled laundry to avoid contactwith lesion exudates. Soiled laundry should not be shaken or otherwise handledin a manner that may aerosolize infectious particles.12 EPAregistered hospitaldetergent-disinfectant may be used for cleaning.

West Nile Virus

With West Nile, we now have a new endemic virus in the U.S., says SallyPaulson, PhD, associate professor of entomology at Virginia Tech in Blacksburg,Va. Were not going to eradicate it. I think that its going to become just like St.Louis encephalitis or eastern equine encephalitis and some of the otherarboviruses that occur in the U.S. Were just going to have to live with it.

WNV is commonly found in Africa, West Asia, and the Middle East. The disease seems to have more neurologic complications here in the UnitedStates than it did in the Middle East, Sinnott says. It is unclear whetherthis is a change in the genetic makeup of the virus or whether we are asusceptible host population.

In July, the Food and Drug Administration (FDA) approved a new diagnostictest for WNV that is to be used as part of a comprehensive evaluation of asymptomatic person, which also includes a physical exam and laboratory tests.The test measures IgM, a type of antibody that emerges in the infection. Paulsonnotes that previous tests for WNV were accurate, but caused an inherent delay inconfirmation of identifying positive cases.

With this IgM test, the IgM antibodies develop much faster in an infectionand its very transient. The titer drops off very quickly. So, if you get apositive test of somebody with a high IgM, its a good indication that theyhave a current or recent infection, she says.

Most individuals infected with WNV remain aysmptomatic, but approximately 20percent of individuals develop a mild illness. With an incubation period ofthree to 14 days, WNV infection is marked by flu-like illness with fever,headache, body aches, rash and muscle weakness. Severe infections infrequently result in encephalitis, meningitis ormeningoencephalitis. No specific treatment for WNV infection is available, but intensive supportive therapy may be required for severe cases.13

The virus is a member of the flavivirus group, which is spread by insects.WNV not only spreads to humans by mosquito bites, but also through bloodtransfusions, organ transplants, and mother-to-child during pregnancy andbreastfeeding. A few documented cases showed that WNV was transmitted tolaboratory personnel through percutaneous injuries.14

In both cases, the individuals were working with infected animals and nothuman patients, Paulson says. But, thats the mechanism you wouldexpect. Tissue contaminates a needle or a scalpel and then an individualaccidentally sticks themselves that way.

Although HCWs are at low risk of WNV infection through normal occupationalcontact with suspected or known infected patients, the National Institute forOccupational Safety and Health (NIOSH) suggests that HCWs follow standard anddroplet precautions.

Many times when youre working with a patient youre not going to knowuntil later that they had West Nile, just like (with other viruses). So,(standard) precautions are very effective for West Nile. If somebody should havea needlestick incident or something, they should report it just as they usuallywould, Paulson says.

Whether its SARS, monkeypox or WNV, Morse emphasizes, All those fairlysimple infection control precautions are very important because many of thesediseases can gain a foothold as SARS did. Many of the cases are often in thehospital and healthcare setting.