Rickettsia africae, a tick-borne pathogen in travelers to sub-Saharan Africa.

BACKGROUND: African tick-bite fever occurs after contact with ticks that carry Rickettsia africae and that parasitize cattle and game. Sporadic reports suggest that this infection has specific clinical and epidemiologic features. METHODS: We studied patients who were tested for a rickettsial disease after returning from a visit to Africa or Guadeloupe. To assess the value of the microimmunofluorescence assay, Western blotting, and cross-adsorption assays, we compared the results of these tests in 39 patients in whom African tick-bite fever had been confirmed by the polymerase-chain reaction assay, cell culture, or both; 50 patients with documented R. conorii infection; and 50 blood donors. These diagnostic criteria were then applied to 376 additional patients who had returned from southern Africa and 2 who had returned from Guadeloupe and whose serum was being tested for rickettsial disease. RESULTS: In the 39 patients with direct evidence of R. africae infection, the combination of microimmunofluorescence assay, Western blotting, and cross-adsorption assays showing antibodies specific for R. africae had a sensitivity of 0.56; however, each test had a positive predictive value and a specificity of 1.0. An additional 80 patients were found to have an R. africae infection on the basis of these serologic criteria. Infections with R. africae were acquired by visitors to 11 African countries and Guadeloupe. The illness was generally mild and was characterized by a rash in 46 percent of the patients; the rash was usually maculopapular or vesicular and rarely purpuric. Ninety-five percent of patients had an inoculation eschar or eschars, and 54 percent of these patients had multiple eschars, a finding that is unusual in patients with rickettsial infection. CONCLUSIONS: In this series, R. africae was the cause of nearly all cases of tick-bite rickettsiosis in patients who became ill after a trip to sub-Saharan Africa.

Evolution of legionnaires' disease in an urban hospital - abstract

Ongoing epidemiological surveillance for nosocomial Legionnaires' Disease (LD) was initiated after control of an initial outbreak involving eight cases at a Nova Scotia Hospital in 1984. All cases of nosocomial pneumonia were screened for LD, and water samples were cultured for Legionella at intervals. No clinical cases of LD were identified until April, 1987, although there were occasional positive cultures from water samples in different areas of the hospital. Subsequently, six to seven cases have been identified over each 12-month period with no more than two cases in any month. The mean age of patients was 67.7 years (range 54 - 83) with a male to female ratio 2.5:1. The mean time of onset of pneumonia after admission was 19.9 days (range 8 - 27) with diagnosis being made in most cases by sputum culture. Risk factors included smoking, immunosuppressive therapy and admission to a specific wing of the hospital. Water samples from the specific wing of the hospital were persistently positive at high levels until certain plumbing revisions were instituted. In contrast to the initial outbreak, these cases represent an endemic level of nosocomial LD related to a specific area of the hospital. Ongoing surveillance is required for detection and control (AU)

Pneumocystis pneumonia in the acquired immune deficiency syndrome (AIDS) - abstract

We present a retrospective analysis of Pneumocystis carinii pneumonia (PCP) in patients with AIDS at our institution. Data were collected by chart and radiological review. Since February 1983 we have treated 24 patients with AIDS and PCP. All except three were homosexual males, with seventeen (17 percent) having PCP as the initial manifestation of AIDS. All patients had CXR changes on presentation. Three had atypical changes including lobar consolidation and multiple cavities. Arterial pO2 on room air ranged from 33 to 83 (av. 59). Diagnosis was made in 28 of 30 episodes (93 percent) using bronchoalveolar lavage. One patient was positive on induced sputum, and one had a positive open lung biopsy. Other respiratory pathogens were also isolated in 20 of 30 episodes (67 percent). Therapy was initiated with trimethoprim-sulpha (T-S) or pentamidine (P). Seven of 21 episodes (33 percent) were successfully treated with T-S alone vs one of nine (11 percnet) with P alone. Eight of 21 (38 percent) experienced adverse effects with T-S vs six of nine (67 percent) with P. Adjunctive steriod therapy was required in 11 of 30 episodes (37 percent) with four deaths subsequently. Overall, six of 30 episodes (20 percent) resulted in death, three in association with concomitant CMV infection. Six of 24 patients (25 percent) had two or more episodes of PCP occurring within 5-17M. (av. 9M) of successful therapy. Our experience parallels that reported from other centres in North America (AU)