Marburg Situation Worsens
By Eric Toner, M.D., April 12, 2005
While it is known that the number of Marburg cases and deaths continues to rise, at this point the true extent of the outbreak remains unclear. The WHO's Aprill 11 update indicates that 214 cases have been reported from 7 of 15 provinces in Angola, with 194 deaths. There are unconfirmed reports of cases in neighboring Congo, and reports of secondary transmission in Luanda, a city of several million. Whether the apparent increase in cases over the last few days represents rapid spread of the epidemic or improved surveillance has yet to be determined. The outbreak is likely to be larger than it now appears due to the difficulty of tracking down cases. Unfortunately, the WHO suspended efforts to find new cases in Uige following an attack on its workers.
The mortality rate is also unclear. To calculate mortality one must know how many infected people ultimately die, but at this point it is only possible to know how many people have died to date. The number of non-lethal cases cannot be determined until spread of the infection has been halted. What is clear is that this is a terrible disease, and as yet there have been no reports of survivors.
The WHO reports that hospitals are a primary vector for spreading the illness and have recommended closure of some hospitals. Due to lack of even rudimentary supplies, hospitals are unable to protect healthcare workers or prevent nosocomial spread of the disease. In addition, news reports indicate that some victims are avoiding hospitals and are dying at home or in the community.
As international aid organizations respond to the outbreak, the possibility of spread to remote counties may increase as relief workers return home. It would be prudent for clinicians who might be charged with the care of such returning health care workers to review the clinical features of the disease and infection control recommendations, both of which can be found posted on the CDC’s website. Recommendations include adherence to strict contact and fluid precautions and negative pressure airborne precautions. While Marburg virus has been spread by contact with skin, blood, and bodily fluids in Africa, the potential does exist for aerosol spread in a modern ICU where invasive and heroic procedures are performed.
Physicians Fail to Diagnose Boston University Tularemia Cases
By Brad Kramer
In November 2004, Boston University reported three cases of tularemia to the Boston Public Health Commission. All three cases occurred in laboratory researchers who believed they were working with the avirulent live vaccine strain of Francisella tularensis. They did not realize that the material they handled was contaminated with highly virulent Type A F. tularensis. A report released on March 28 by the Boston Public Health Commission provided an overview of the tularemia outbreak, reporting among other findings that all three of the infected researchers were seen by physicians, treated with antibiotics, and recovered, yet “Tularemia infection was not diagnosed by any of the treating physicians.” Details on the nature of the physician visits were not included in the report, but one might suppose that a thorough occupational history from the first two workers in May, 2004 might have identified the causative agent and source of exposure, thus preventing the third case in September.
The failure to diagnose tularemia in these researchers highlights the important role that clinical astuteness and careful history taking may play in early recognition of a lab accident or bioterrorism event. Furthermore, it points out that, as was seen with both incidences of SARS lab infections, laboratory workers may have a tendency to underestimate their risk of occupational infection and thus may not volunteer critical exposure information. Physicians should take at least a brief occupational history on every patient with a febrile illness. If a patient’s occupation involves work with microbes, follow up to identify specific organisms handled by the patient is warranted even if the patient is reluctant.