Protecting Healthcare Staff
From Todays Emerging Infectious Diseases
By Tina Brooks
Healthcare workers (HCWs) face a wide range of hazards on the job, including emerging infectious diseases such as severe acute respiratory syndrome (SARS), monkeypox and West Nile virus (WNV). It is possible, however, to prevent or reduce HCWs exposure to todays infectious threats.
Stephen S. Morse, PhD, associate professor of the Center for Public Health Preparedness at the Mailman School of Public Health of Columbia University in New York says, I think one of the most important things is for people, both in the professional community and also the public at large, to be well and accurately informed.
A clearer understanding of SARS has evolved since the appearance of this coronavirus in 2002. The severity of the illness is variable, ranging from mild illness to death. The Centers for Disease Control and Prevention (CDC) reports that the incubation period for SARS is two to seven days; however, isolated reports have suggested as long as 10 days.1 The illness begins with a fever greater than 100.4 degrees F (>38.0 degrees C). Other symptoms may include headache, muscle aches, cough, shortness of breath and difficulty 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 from direct 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 where infection-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 undergoes amplification. In other words, HCWs are more easily infected than the general population. If you look at the patients of SARS, an astounding percentage is hospital workers.
When caring for suspected or known SARS patients, HCWs should be trained in the correct use and removal of appropriate personal protection equipment (PPE), including protective gowns, gloves, N95 respirators and eye protection.5 Although 11 HCWs in Toronto had worn the recommended PPE each time they entered a patients room, they were infected with SARS. Interviews with the infected HCWs revealed that PPE had not been fit tested prior to use and an understanding of the correct order of removal of PPE varied among the workers.6
Its clear that with SARS there were some rather high-risk types of occupational settings, respiratory therapy and intubation, for example, Morse says.
Putting tubes or other types of invasive procedures in the respiratory tract, which for obvious reasons, increase HCWs risks more than the emergency room.
If there is a potential for exposure to blood or other infectious materials, Occupational Safety and Health Administration (OSHA) regulations state that HCWs must use PPE in accordance with its Bloodborne Pathogens Standard.7
The housekeeping and environmental services department personnel also should use PPE as required for contact and airborne precautions as long as the patient is in the room. Daily cleaning should include horizontal surfaces (e.g., over-bed tables and nightstands), surfaces that are frequently touched by patients and healthcare personnel (e.g., bed rails, phone), and lavatory facilities.8 While terminal cleaning should include aforementioned surfaces described 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 CDC recommends the use of any Environmental Protection Agency (EPA)-registered hospital detergent-disinfectant for environmental sanitation.
Although discovered in laboratory monkeys in 1958, monkeypox was not reported in humans until 1970. Recent investigations implicated a shipment of animals from Ghana as the probable source of introduction of the virus into the United States. 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, but milder. Approximately 12 days after infection with this orthopoxvirus, individuals often experience a fever, headache, muscle aches, backache and swollen lymph nodes.10 One to three days after the start of fever, a rash that develops into raised bumps filled with fluid. The bumps eventually scab over and fall off. The illness lasts from two to four weeks. Smallpox vaccination has been reported to reduce the risk of monkeypox infection.
The virus is typically transmitted to humans by contact with an infected animal. Monkeypox, which is less infectious than smallpox, can also be spread from person to person. Direct contact with infected human body fluids or with virus-contaminated objects, such as bedding or clothing, can spread the virus as well. Sinnott says Thus far in the United States we havent seen any person-toperson transmission, but that potential is there.
Transmission of monkeypox within hospitals has occurred.11 Similar to SARS, a combination of standard, contact and droplet precautions should be applied. Housekeeping should be careful when handling soiled laundry to avoid contact with lesion exudates. Soiled laundry should not be shaken or otherwise handled in a manner that may aerosolize infectious particles.12 EPAregistered hospital detergent-disinfectant may be used for cleaning.
West Nile Virus
With West Nile, we now have a new endemic virus in the U.S., says Sally Paulson, 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 other arboviruses 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 United States than it did in the Middle East, Sinnott says. It is unclear whether this is a change in the genetic makeup of the virus or whether we are a susceptible host population.
In July, the Food and Drug Administration (FDA) approved a new diagnostic test for WNV that is to be used as part of a comprehensive evaluation of a symptomatic person, which also includes a physical exam and laboratory tests. The test measures IgM, a type of antibody that emerges in the infection. Paulson notes that previous tests for WNV were accurate, but caused an inherent delay in confirmation of identifying positive cases.
With this IgM test, the IgM antibodies develop much faster in an infection and its very transient. The titer drops off very quickly. So, if you get a positive test of somebody with a high IgM, its a good indication that they have a current or recent infection, she says.
Most individuals infected with WNV remain aysmptomatic, but approximately 20 percent of individuals develop a mild illness. With an incubation period of three 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 or meningoencephalitis. 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 blood transfusions, organ transplants, and mother-to-child during pregnancy and breastfeeding. A few documented cases showed that WNV was transmitted to laboratory personnel through percutaneous injuries.14
In both cases, the individuals were working with infected animals and not human patients, Paulson says. But, thats the mechanism you would expect. Tissue contaminates a needle or a scalpel and then an individual accidentally sticks themselves that way.
Although HCWs are at low risk of WNV infection through normal occupational contact with suspected or known infected patients, the National Institute for Occupational Safety and Health (NIOSH) suggests that HCWs follow standard and droplet precautions.
Many times when youre working with a patient youre not going to know until later that they had West Nile, just like (with other viruses). So, (standard) precautions are very effective for West Nile. If somebody should have a needlestick incident or something, they should report it just as they usually would, Paulson says.
Whether its SARS, monkeypox or WNV, Morse emphasizes, All those fairly simple infection control precautions are very important because many of these diseases can gain a foothold as SARS did. Many of the cases are often in the hospital and healthcare setting.