Natural attenuation/phytoremediation in the vadose zone of a former industrial sludge basin.

The natural attenuation of polyaromatic hydrocarbons (PAHs) in the vadose zone of a naturally revegetated former industrial sludge basin (0.45 ha) was examined. This was accomplished by comparing the concentration of 16 PAH contaminants present in sludge collected below the root zone of plants with contaminants present at 3 shallower depths within the root zone. Chemical analysis of 240 samples from 60 cores showed the average concentration of total and individual PAHs in the 0-30 cm, 30-60 cm, and bottom of the root zone strata were approximately 10, 20, and 50%, respectively, of the 16, 800 ppm average total PAH concentration in deep non-rooted sludge. Statistically significant differences in average PAH concentrations were observed between each strata studied and the non-rooted sludge except for the concentrations of acenaphthene and chrysene present at the bottom of the root zone in comparison to sludge values. The rooting depth of the vegetation growing in the basin was dependent on both vegetation type and plant age. Average rooting depths for trees, forbs (herbaceous non-grasses), and grasses were 90, 60, and 50 cm, respectively. The deepest root systems observed (100-120 cm) were associated with the oldest (12-14 year-old) mulberry trees. Examination of root systems and PAH concentrations at numerous locations and depths within the basin indicated that plant roots and their microbially active rhizospheres fostered PAH disappearance; including water insoluble, low volatility compounds, i.e. benzo(a)pyrene and benzo(ghi)perylene. The reduced concentration of PAHs in the upper strata of this revegetated former sludge basin indicated that natural attenuation had occurred. This observation supports the concept that through appropriate planting and management practices (phytoremediation) it will be possible to accelerate, maximize, and sustain natural processes, whereby even the most recalcitrant PAH contaminants (i.e. benzo(a)pyrene) can be remediated over time.

Increase in community-acquired methicillin-resistant Staphylococcus aureus at a Naval Medical Center.

A retrospective review of methicillin-resistant Staphylococcus aureus isolates from the Naval Medical Center, San Diego, for the years 1994 through 1997, found that the annual number of community-acquired MRSA isolates increased during the period. These outpatient isolates were more likely than inpatient isolates to be sensitive to a greater number of antibiotics.

Canines as sentinels for Lyme disease in San Diego County, California.

Prevalence of Lyme borreliosis in canine sentinels has been shown to correlate with infection in humans. One thousand canine sera (917 dogs, 83 coyotes) obtained from animal control authorities and area veterinarians were screened by ELISA for antibodies to Borrelia burgdorferi. Results were validated by Western blot and indirect fluorescent antibody (IFA) tests at referee laboratories. Criterion for a positive Western blot was presence of 5 of 10 of the most common antigen IgG bands; for IFA, >1:128 or the equivalent when correcting for interlaboratory variability. Twenty-two of 1,000 canines were confirmed serologically positive (21 dogs and 1 coyote; seroprevalence 2.3% and 1.2%, respectively). Lifestyle, breed size, gender, and age were not statistically predictive of seropositive status. No regional clustering of seropositive animals was detected. The low prevalence of seropositivity in sentinel canines suggests the Lyme borreliosis hazard in San Diego County is minimal.

Ecological recovery of vegetation at a former industrial sludge basin and its implications to phytoremediation.

Examination of a former industrial sludge basin containing organic pollutants showed that the basin had undergone substantial ecological recovery through natural forces following the removal of surface water in 1982. Conventional phases of ecological recovery (plant invasion and succession) have occurred, but the structure of the biodiverse plant community (51 species and 22 families) was different from that at a recovering non-polluted disturbed site. Three plant species (Bermuda grass, mulberry, and sunflower) believed to be early invaders of the basin still persist in large numbers indicating that these species are well suited to cope with normal environmental stresses at this area (i.e. seasonal drought and flood) as well as organic pollutants. There was an indication that early invaders of the site fostered disappearance of contaminants thereby creating more favorable conditions for a broader spectrum of plants to grow. Vegetation analyses of naturally vegetated hazardous waste sites hold promise as a screening device for identifying plant species and management practices worthy of further phytoremediation investigations.

Staphylinid (rove) beetle dermatitis outbreak in the American southwest?

An outbreak of a blistering disease was reported in a military unit training in the Arizona desert during heavy rain and flooding. In a unit of 249 personnel, 33 presented with dermatologic complaints, and 4 met stringent diagnostic criteria for dermatitis linearis. A fifth patient presented with symptoms and signs of "Nairobi eye." Staphylinid (rove) beetles related to the paederids, which have been responsible for vesicular dermatitis outbreaks in other parts of the world but not previously in the United States, were collected at the site. Reports in the antique scientific literature document paederids in the area after periodic floods. These findings suggest that rove beetle dermatitis should be added to the differential diagnosis of vesicular dermatitis in western North America.

Effects of influenza vaccination in HIV-infected adults: a double-blind, placebo-controlled trial.

Annual influenza vaccine is recommended for persons with HIV infection. Recent reports indicate that immunizations may increase HIV replication in infected individuals. Forty-seven HIV-infected patients were randomized to influenza vaccine or saline placebo using a double blind study design. One month after vaccination, plasma HIV-1 RNA increased in the vaccinated but not placebo group (p = 0.029). At 3 months, CD4% dropped an average of 1.6 points in the vaccinated group compared to an increase of 0.1 points in the placebo group (p = 0.039). Patients on stable antiretroviral regimens had CD4% drop an average of 2.3 points in the vaccinated group at 3 months versus 0.1 points in the placebo group (p = 0.015). It is concluded that HIV-infected patients are at risk for increased HIV replication and decreases in CD4% following influenza vaccination. Since influenza has not been associated with significant morbidity in this population, further study of routine influenza vaccination for HIV-infected patients is warranted.

Reliability of a history of previous varicella infection in adults.

CONTEXT: Apparent second episodes of varicella are reported in immunocompetent hosts, but laboratory confirmation of prior immune status has rarely been possible. OBJECTIVE: To evaluate adult patients with varicella who claimed to have had previous varicella to determine whether they had true second episodes or primary cases with inaccurate clinical histories. DESIGN: Adult subjects with varicella who enrolled in an antiviral treatment trial were interviewed about a history of varicella. The clinical course of varicella was documented prospectively in all subjects. Serum samples that predated the acute illness were obtained from the US Navy's central serum storage facility for subjects who reported a previous episode of varicella. These stored samples were tested in parallel by enzyme-linked immunosorbent assay, latex agglutination, and Western blot for IgG antibodies to varicella-zoster virus (VZV). PARTICIPANTS: Twenty military personnel with varicella and a history of the disease. SETTING: A military hospital in San Diego, Calif. MAIN OUTCOME MEASURE: Presence or absence of antibodies to VZV. RESULTS: Twenty (10.8%) of 184 adults with serologically confirmed acute varicella reported a prior history of varicella. The clinical course of these 20 patients did not differ from those with no history of varicella. Serum samples that had been collected a mean of 12.4 months (median, 12 months; range, 3 days to 34 months) before the incident episode were available for 19 subjects. All 19 serum samples lacked IgG antibodies to VZV. CONCLUSION: A history of previous varicella infection in adults with varicella may not be reliable. True second episodes of varicella are probably rare in immunocompetent adults.

Association of schistosomiasis with cervical cancer: detecting bias in clinical studies.

To investigate if Schistosoma haematobium infection increases the observed frequency of cervical cancer, data from literature were analysed in meta-analysis fashion. Results reveal that cervical cancer is statistically significantly less frequent in the presence of S. haematobium infection. A protective effect might be inferred; however, underlying bias in data collection and/or analysis is suspected. An approach to detecting bias is given, consisting of: (a) carefully stating and assessing the several components of the scientific method and; (b) identifying and contrasting the populations hypothesised and sampled. The approach is illustrated by searching for bias in the schistosomiasis-and-cancer reports. Sampling discrepancies were detected in patient geography, ages, and states of health, and suspected in disease prevalence sampled and disease prevalence reported. The conclusion is reached that effects of bias in the original studies preclude inference of a "protective" effect of S. haematobium infection against cervical cancer.

Coccidioidomycosis in California: regional outbreak, global diagnostic challenge.

Beginning in 1991, case reports of coccidioidomycosis in California increased dramatically, pursuant to a variety of natural and demographic factors. This highly infectious fungal disease with propensity to disseminate widely, mimic other conditions, and cause pathology at locations distant in place and time is readily treatable if recognized at an early stage. The concentration of military bases in endemic areas and the mobility of military personnel suggest a heightened potential for case presentations elsewhere and a need for elevated diagnostic suspicion on the part of military physicians worldwide. We review three cases of disseminated disease recently referred to our facility.

Tumor necrosis factor, interleukin-2, and interferon-gamma in adult varicella.

Adult varicella can be a severe illness complicated by pneumonia, encephalitis, or prolonged fever. This study measured levels of tumor necrosis factor (TNF)-alpha, interleukin-2 (IL-2), and interferon gamma (IFN-G) in a consecutive group of 31 adult varicella patients presenting within 24 hours of rash onset. All cytokines were assayed using an ELISA technique. TNF-alpha was detectable in 71% of patients with a mean level of 52 pg/ml. IL-2 was detectable in 29% with a mean level of 1040 pg/ml. IFN-gamma was detectable in only 9%. There was no correlation between TNF, IL-2, or IFN-G level and clinical severity as determined by duration and severity of cutaneous findings, duration of fever, frequency of hepatitis, or thrombocytopenia.