Updates

by Carol A. Kemper

Longer-Term Symptoms of WNV Fever

Source: Watson J, et al. Ann Intern Med. 2004;141:360-365.

West Nile virus infection without central nervous system involvement is generally believed to be a self-limited febrile illness, lasting about 3-7 days. Recent data suggest, however, this may not be the case. Watson and colleagues surveyed the clinical manifestations of non-paralytic/nonCNS WNV infection in 98 patients with WNV fever, finding that symptoms were of greater severity and duration than previously recognized.

As part of an investigation of the WNV outbreak in Illinois in 2002, patients diagnosed with WNV fever without CNS or paralytic involvement were later contacted and asked to participate in a telephone survey. Of the 140 persons residing in the catchment area, 98 (42%) were eligible and willing to participate (38 could not be located, 3 were unwilling or unable to participate, and 1was younger than 3 years of age). Importantly, while all of the patients had laboratory confirmation of WNV infection, none of them had undergone lumbar puncture. Thus, the diagnosis of WNV fever, as distinct from meningoencephalitis, was based on the individual practitioner’s clinical judgement. Interviews were conducted on average about 5 months after illness onset. About one-fourth of the patients were older than 65 years of age.

Of the 98 patients surveyed, 96% reported fatigue for a median of 36 days, 81% had fever for a median of 5 days, 71% had headache for a median of 10 days, 61% had muscle weakness for a median of 28 days, and 53% had difficulty concentrating for a median of 14 days. Rush occurred in 57%, and lasted a median of 7 days. About one-third were hospitalized for a median of 5 days, and about one-half missed a median of 10 days of work or school. One month after illness onset, 63% of patients remained symptomatic, and the overall median time to a self-reported full recovery was 2 months. The time to recovery was similar between younger and older patients, and did not seem to be affected by the presence of underlying disease (eg, diabetes).

This sample may have represented patients who were generally more ill: patients who presented for medical evaluation with WNV may be more ill than those who choose not to seek medical care; and without the benefit of examination of CSF, some of these patients may have had an aseptic meningitis or mild encephalitis, which could contribute to a more prolonged duration of symptoms. In addition, these findings were based on patient self-reports, sometimes many months following the acute illness, possibly introducing recall bias. Nonetheless, even in the absence of focal neurologic symptoms, self-reported symptoms of WNV infection may be more significant, with a longer time to recovery that previously recognized.

Hepatitis E Hits Iraq

ProMED-mail post, September 23, 2004; www.promedmail.org.

An outbreak of hepatitis E, which is generally spread by fecally contaminated water, is occurring in 2 areas of Iraq, where the water and sewage systems have been disrupted by the war. Cases of typhoid fever are also increasing. The outbreak is centered in Sadr City, a poverty- and war-ravaged slum in southern Baghdad, as well as in Mahmudiya, about 56 miles south of Baghdad, which has been a center of recent kidnappings and drive-by shootings. At least 215 cases have been diagnosed and 5 people have died, including 1 pregnant woman. This is twice the annual number of cases reported across Iraq in 2002 before the United States invasion, and a significantly higher death rate than expected for hepatitis E (hepatitis E is typically a self-limited form of acute viral hepatitis, lacking a chronic infectious phase, similar to hepatitis A). Health officials, who are limited in their ability to examine and test potential cases, fear that the actual number of cases may be much greater. Attempts to proceed with construction of a water treatment facility in Baghdad have been suspended given problems guaranteeing worker safety and security.

Maggot You Another Appetizer?

Sherman RA, et al. Clin Infect Dis. 2004;39:1069.

You can’t find much about maggots in your standard ID texts, but they are approved by the US Food and Drug Administration for use in wound debridement. Interest in maggot therapy for treatment of open necrotic wounds—which first became popular during World War I—is being renewed. Maggots, those helpful little offspring of the green blowfly, Phaenicia sericata, can be disinfected during the egg stage, so they don’t conversely contribute to the risk of infection, and applied directly to necrotic wounds, thereby reducing the risk of infection following surgical repair.

Sherman and colleagues retrospectively examined their hospital experience with Maggot Debridement Therapy, and found that none of 10 wounds, in which maggots were used within 3 weeks prior to surgery, developed infection. In contrast, 6 of 19 (32%) similar wounds treated with the usual conservative measures became infected. Remarkably, in addition to eating dead tissue, maggots secrete an antibacterial agent that helps prevent wound infection and promotes wound healing. The only draw back, observed 1 member of the surgical team, was that maggots don’t exactly come in a jar from central supply: a new batch had to be grown fresh and applied every day.

SARS and the Environment

Dowell SF, et al. Clin Infect Dis. 2004; 39:652-657.

A central question remaining from the SARS outbreak was the mode of transmission of virus in situations where direct patient contact or droplet exposure had not occurred, such as on airplanes, within floors of a hotel, or in certain hospitals, where nosocomial spread occurred to employees not directly involved in patient care. Dowell and colleagues from the CDC, in conjunction with the Thai Ministry of Health, examined environmental surface contamination with SARS corona-virus (Co-V) in 2 Thai hospitals at the heart of the SARS epidemic in 2003.

Overall, 22 of 90 (24%) environmental swab specimens were PCR positive for SARS Co-V, as were all 4 specimens from patients hospitalized with SARS during the study. However, important differences were observed between the 2 hospitals, and all but 1 of the positive specimens was obtained from 1 of the hospitals. That hospital was in the midst of the epidemic, with more than 2 dozen case-patients hospitalized on 2 separate floors. The hospital had just been closed 5 days earlier, and all patients, healthcare workers, and visitors quarantined as the extent of the epidemic—and the risk of nosocomial spread—was recognized. The use of personal protective equipment (PPE), ventilation guidelines, and environmental cleaning was inconsistent. As a result, 12 of 43 specimens from patients rooms, and 10 of 47 specimens from other areas of the hospital, including computer mouses at 2 work stations, the nurses breakroom doorknob and toilet handle, and one of the telephones at the nurses station were PCR positive for virus. Fortunately, only 1 specimen from a more public area in the hospital was positive (an elevator handrail). None of the paired cultures were positive.

In contrast, the second hospital examined in this survey provided care for several suspect cases, one of whom tested positive for SARS Co-V, and who died after 18 days of hospitalization. Eighteen specimens were obtained from the patient, his surroundings, and the nurses station within 2 hrs of his death; only 1, from the subject’s nasopharynx, was PCR positive for SARS Co-V. Infection control practices and the use of PPE in this hospital were more rigorously applied, and the situation was not as chaotic.

While it is possible that the positive PCR specimens represented non-viable virus, other coronavirus has been shown to survive on surfaces for several days, at least in a stable, moist environment. In addition, patients in the first hospital, who were acutely ill, may have been more likely to shed greater amounts of virus, than a patient on the 18th day of illness, when viral load would be expected to be much lower. Nonetheless, these findings highlight the differences in infection control practices between the 2 hospitals, and the risk for nosocomial spread. While most transmission of SARS Co-V is believed to occur through person-to-person spread or large droplet exposure, these findings suggest that transmission may also occur because of environmental contamination or fomites. Patients, visitors, and staff working in hospitals with SARS patients should be made aware that the virus may be present outside patient rooms, despite infection control efforts to limit contamination.

Carol A. Kemper, MD, FACP, Clinical Associate Professor of Medicine, Stanford University, Division of Infectious Diseases; Santa Clara Valley Medical Center, Section Editor, Updates, Section Editor, HIV, is Associate Editor for Infectious Disease Alert.