Updates
By Carol A. Kemper, MD, FACP
Can HAART Worsen PCP?
Source: Wislez M, et al. Am J Respir Crit Care Med. 2001;164:847-851.
Wislez and colleagues describe 3 HIV-infected patients being treated for Pneumocystis carinii pneumonia (PCP) who developed respiratory function following initiation of highly active antiretroviral therapy (HAART). All 3 patients had severe PCP that had initially improved with antiPCP treatment and adjunctive corticosteroids (the latter was administered for 2 weeks). HAART was begun within 1 to 16 days of diagnosis and initiation of treatment. Within 7 to 17 days after intitiation of HAART, all 3 patients developed respiratory failure with recurrent fever and patchy alveolar infiltrates. Following discontinuation of HAART and reintroduction of steroids, all 3 eventually improved.
This report is interesting for all kinds of reasons. Based on reports that initiation of HAART during acute OI may speed recovery, it has been recommended that HAART be administered as soon as possible to all such patients. On the other hand, there are increasing reports that the initiation of antiretroviral therapy can trigger a variety of inflammatory responses, presumably because of enhancement of the immune response, with worsening, for example, of underlying hepatitis, mycobacterial infection, and CMV.
It is known that about 10% of patients with PCP experience deterioration in respiratory function within 3-7 days of initiation of antiPCP treatment, an effect that is mitigated by the administration of adjuvant corticosteroids. Hence the widespread use of corticosteroids in the treatment of moderately-severe-to-severe PCP (A-a gradient ³ 30). The original California Collaborative Treatment Group protocol from the early 1990s specified 21 days of adjuvant corticosteroids, which has been shortened to 2 weeks by some clinicians because of concerns of immune suppression. Anecdotal reports have, however, described patients with premature "flares" of PCP when corticosteroids were stopped prematurely at 10 or 14 days. Whether the deterioration in respiratory function in these patients with severe PCP occurred because of the normal course of disease, the administration of HAART, or the premature discontinuation of steroids is not known, but a controlled trial to answer this question is probably no longer possible.
An Ephemeral Virus?
Sources: ProMED mail post, October 16, 2001; Kliatchko IR. The Manila Times. October 12, 2001.
This unusual report describes a lesser known virus, bovine ephemeral fever (BEF) virus, which causes significant morbidity in cattle and buffaloes in Asia, Africa, and Australia. A member of the family Rhabdoviridae, which also includes vesiculoviruses such as vesicular stomatitis virus, this ephemerovirus is transmitted by mosquitos, and is widespread in certain areas. Infection is associated with acute pharyngoesophageal paralysis, muscular weakness and twitching, and acute paresis, possibly from hypocalcemia. Eventually the animal weakens and develops permanent paresis from cervical myelopathy. While the mortality is ~4-13%, the morbidity is significant (~50%); administration of anti-inflammatories and calcium may diminish symptoms. Detection of infection is complicated by cross-reactivity with other similar rhabdoviridae. A vaccine is available but must be administered annually.
Hotel Histo!
Source: ProMED-mail post. October 16, 2001. [email protected].
An earlier report this year described a series of 229 students from 44 colleges throughout the United States who had developed histoplasmosis after traveling to Acupulco for spring break during the first 2 weeks of March (Kemper CA. Infectious Disease Alert. 2001;20:144). The possible source of infection had not been identified but the Calinda Beach hotel was a suspect. In total, more than 400 guests of the hotel reported developing symptoms of histoplasmosis last spring. However, when guests who had stayed at the hotel in September began complaining of symptoms of histoplasmosis, authorities finally acted in October to close the hotel. The specific focus of infection in the hotel or the grounds still had not been identified.
Anthrax—Northern California
Source: ProMED-mail post. November 1, 2001. [email protected].
By some amazing coincidence, between October 20 and 26, 21 cattle in the southern part of Santa Clara County, California (where I work) developed acute anthrax infection and died. All of the cattle, which belonged to a single ranch about 5 miles south of Morgan Hill, have been buried, and another 120 have been vaccinated. At least 15 people, including the veterinarian who performed the necropsies in the field, several ranch hands, and 10 laboratory workers who handled the samples have received prophylactic antibiotics.
Anthrax in cattle is not unheard of—just uncommon in these parts. Before this report, there were only 10 reported cases of anthrax in cattle in California during the past 10 years! Because the spores can lay dormant in soil for many years, cattle, elk and other ruminants are more vulnerable to infection, especially when the soil is dry or overgrazed. Interestingly, the veterinarian who initially examined the cattle in the field found no overt signs of anthrax; specifically, there were no signs of hemorrhage, which may be a clue but is not invariably present. Since the events of early October on the East Coast, authorities have alerted large animal vets to be alert for similar outbreaks.
Dr. Kemper, Clinical Associate Professor of Medicine, Stanford University, Division of Infectious Diseases, Santa Clara Valley Medical Center, is Associate Editor of Infectious Disease Alert.
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