Invasive pneumococcal disease in a cohort of HIV-1 infected female prostitutes living in Nairobi

A cohort of predominantly HIV seropositive female prostitutes has been followed for a two year period. 54 episodes of invasive pneumococcal disease (ISpD) have been diagnosed in 41 patients; of which 28 were bacteraemic. All patients were seropositive for HIV. Pneumonia was the most common presentation in 34(64); then maxillary sinusitis in 11 (21) and occult bacteraemia in 8 (15). Nine of the patients (22) had proven recurrent disease despite appropriate therapy; most of these episodes were with different serotypes suggesting that this is reinfection rather than relapse. The mean CD4 count of first episode ISpD was 325 showing that that this is an early HIV-related problem. The estimated inicdence rate was 30/1000 person years of observation and it was the most common life-threatening problem seen in the cohort in the study period. All patients survived with standard penicillin or ampicillin treatment. The pneumococcus is an important but under-recognised cause of HIV-related disease in Africa. Presentation can be atypical but the response to appropriate therapy good

Characterization of a monoclonal antibody that neutralizes the hyaluronidase activity of Russell's viper venom.

Three monoclonal antibodies (WPN1, WPN2 and WPN3) raised against a partially purified fraction of Russell's viper venom (RVV) were characterized. All three monoclonal antibodies reacted with crude RVV when tested by ELISA, but only two (WPN1, WPN2) neutralized its hyaluronidase activity. WPN1 was the more potent and was effective at an antigen: antibody ratio of 1:3. Furthermore, WPN1 was shown to recognize only the 14,000 MW component of crude RVV. This has been identified in a previous study to be hyaluronidase. This antibody was also found to recognize some components of Calloselasma rhodostoma venom which also possesses potent hyaluronidase activity. The potential therapeutic role of antibodies that neutralize the hyaluronidase component of snake venoms should be investigated further.

The analysis of 46 fatal snake bite cases in Thailand.

In order to identify aspects of snake bite treatment which could be improved, 46 well-documented cases of fatal snake bite (mortality rate = 2.8%) from 15 provincial hospitals throughout Thailand were selected for analysis (1,626 bites in 84 hospitals). Bungarus candidus and Calloselasma rhodostoma were each responsible for 13 deaths, Naja kaouthia for 12, Vipera russelli for seven and Bungarus fasciatus for one. Major causes of death were respiratory failure and complications of prolonged mechanical ventilation following Elapidae bites; shock, intracranial haemorrhage, complications of local wound necrosis including tetanus, and renal following Viperidae bites. Analysis of these patients’ clinical management revealed the following factors contributing to fatal outcome : inadequate dose of antivenom (15 cases), inappropriate specificity of antivenom (12 cases), inadequate mechanical ventilation (10), late arrival at hospital after traditional treatment (10 cases), artificial ventilation not attempted despite respiratory failure (8), inadequate treatment of hypovolemia including tetanus (6), obstruction of endotracheal or tracheostomy tube (5) and transfer between hospital (5), the treatment of snake bite must be directed both to medical staff and potential patients, particularly the high risk groups in rural areas. This study was supported in part by the Wellcome Trust of Great Britain under the Wellcome-Mahidol University, Oxford Tropical Medicine Research Programme.

Effect of inosiplex on the humoral and cell-mediated immune responses to intradermal human diploid cell rabies vaccine.

Antigen-stimulated lymphocyte transformation was studied in recipients of intradermal human diploid cell rabies vaccine (HDCV). HDCV was administered intradermally at 8 different anatomical sites, 0.1 ml each, on day 0; followed by another 4-site injection on day 7. Rabies antigen-stimulated in vitro proliferative response was evident as early as 7 days after starting immunization. It reached a peak on day 14 and had declined by day 28. The cellular proliferative response preceded and roughly correlated with the antirabies antibody response. Simultaneous administration of inosiplex, an antiviral and immunopotentiating drug, during the first 10 days of intradermal HDCV immunization did not result in heightened antibody titres or cell-mediated immune response to the vaccine. The number of T cells and the lymphocyte proliferative response to phytohaemagglutinin in inosiplex-treated vaccinees were similarly not significantly different from untreated controls. Our results confirm other previous findings that a specific cell-mediated immune response can be consistently and rapidly induced by an intradermal regimen of HDCV immunization. The addition of inosiplex to this regimen did not enhance the humoral or cell-mediated immune responses to the vaccine. The apparent lack of immunostimulating effect of inosiplex in this setting may be the result of several factors such as the immunization schedule and the immunologic parameters examined.

Lack of interferon induction in man by two rabies tissue culture vaccines.

Both neutralising antibody and interferon play a part in protection of animals against death from rabies virus infection. Interferon induction was therefore sought in 53 volunteers within 24 hours of receiving human diploid cell strain vaccine or fetal bovine kidney cell vaccine given either intramuscularly or intradermally. Repeat observations were made in 18 subjects following a second dose of vaccine seven days later. No interferon was detected in any sample tested although no subject had any detectable rabies neutralising antibody on day 0. The sensitivity of the interferon assay, and comparison with other studies are discussed. An interferon inducer suitable for human use should be sought as an alternative to, or a replacement for, passive rabies immunization.