Rabies neutralizing antibody in serum of children compared to adults following post-exposure prophylaxis

Rabies neutralizing antibody concentrations in serum (SRNA) elicited by experimental post-exposure prophylaxis (PEP) regimens are used to assess their potential clinical efficacy. Although PEP with human rabies immunoglobulin (HRIG) plus human diploid-cell culture vaccine (HDCV) is almost completely protective, the limited availability of these components has stimulated the search for alternative regimens. Since 33% to over 60% of PEP is administered to children, a need exists for data on the SRNA response to HRIG plus HDCV in children, to be used to assess the potential value of alternative PEP treatments. We measured SRNA by the rapid fluorescent focus inhibition test on days 0, 1, 3, 7, 14, 28, 56 and 90 after initiation of PEP with HRIG (20 IU/kg) and HDCV (1.0 ml on day 0, 3, 7, 14, 28) in 10 children [8 +/- 4 (mean +/- SD) years of age] and 32 adult control patients (38 +/- 16 years of age). Early, uniform appearance of SRNA was observed with no differences between groups. These data are consistent with the demonstrated efficacy of PEP with HRIG plus HDCV in children as in adults and provide results that can be used for initial evaluation of experimental pediatric PEP regimens in the future.

Giardiasis associated with the use of a water slide

Although Giardia lamblia cysts are an important contaminant of surface water supplies, only one swimming pool outbreak, involving an infant and toddler swim class, has been reported. We describe an outbreak of giardiasis associated with a hotel's new water slide pool which was cleansed by both bromination and sand filtration. Among the 107 hotel guests and their visitors surveyed, 29 probable and 30 laboratory-confirmed cases of Giardia infection were found. Cases ranged from 3 to 58 years of age, with a mean age of 21 years. The 5-year modal age grouping was 5 to 10 years of age. Symptoms in the 59 cases included: diarrhea (48), cramps (38), foul smelling stools (29), loss of appetite (23), fatigue (20), vomiting (18), greasy stools (15), fever (11) and weight loss (10). Four children and 2 adults were hospitalized. Significant associations were found for staying at the hotel, using the water slide pool and swallowing pool water. A possible contributing factor was the emptying of an adjacent toddlers' wading pool, a potential source of fecal material, into the water slide pool. Transmission of Giardia can occur in water slide pools and therefore should be considered in cases of protracted diarrhea among users of such pools.

Immunization: primary prevention par excellence

Immunizing agents and vaccination programs have had a major impact on the health and longevity of our population. The continuation of established programs and the introduction of new programs will undoubtedly remain an integral part of our primary prevention activities. Decisions on the universal need for earlier immunizing agents were relatively straightforward, since most were directed at agents which were extremely communicable, and all were active against agents to which the population was fairly uniformly exposed. Because several of the "newer" vaccines do not meet these criteria, decisions on their use must be reviewed and may need to be based on other criteria. All decisions must take into account the risks and benefits of the vaccines. It must also be accepted that not all beneficial vaccines will necessarily become a part of universal immunization programs.

The clinical diagnosis of genital ulcer disease in men in the tropics

Since the clinical diagnosis of genital ulcers without laboratory confirmation is not reliable in developed countries, we postulated that clinical diagnosis alone would be no more reliable in developing countries. A presumptive clinical diagnosis of chancroid, genital herpes, syphilis, or lymphogranuloma venereum was made for 100 male patients at the Special Treatment Clinic in Nairobi, Kenya. This diagnosis was then compared to the final diagnosis determined by laboratory identification of the pathogen, by culture, or by serologic response. In 64 patients, a final diagnosis of either chancroid, syphilis, or genital herpes was established. The diagnostic accuracy varied from 75% for chancroid to 42% for syphilis and 43% for herpes. The overall diagnostic accuracy was 66%. The predictive values of positive clinical diagnoses were 84% for chancroid, 60% for syphilis, and 75% for herpes. Thus, clinical diagnosis of genital ulcer disease was not sufficiently reliable in this study.

Antimicrobial therapy of chancroid: effectiveness of erythromycin

The emergence of Haemophilus ducreyi resistant to multiple antibiotics has limited the effectiveness of sulfonamides and tetracycline for the therapy of chancroid. A randomized, double-blind study compared 10-day courses of erythromycin base (500 mg) and rosaramicin (250 mg) each given four times daily for the treatment of men with chancroid in Nairobi, Kenya. Of 99 evaluable patients, 84 were positive for H ducreyi. H ducreyi-positive genital ulcers in men treated with either drug resolved with mean +/- SD healing times of 10.8 +/- 5.1 days for erythromycin and 10.7 +/- 5.5 for rosaramicin. There were no clinical or bacteriologic failures with either agent. Fifteen men with H ducreyi-negative genital ulcers for whom no other etiology could be determined also responded rapidly to treatment with either agent. Both erythromycin and rosaramicin are highly effective in the treatment of chancroid.

Treatment of chancroid. A comparison of sulphamethoxazole and trimethoprim-sulphamethoxazole

Since sulphonamides are no longer predictably effective in the treatment of chancroid the combination of trimethoprim-sulphamethoxazole (TMP-SMX) was evaluated to identify other effective regimens. One hundred and nine patients with genital ulcers (75 men and 34 women) seen at the Special Treatment Clinic in Nairobi, Kenya, were randomly assigned to treatment with a seven day course of either sulphamethoxazole 1000 mg twice daily or trimethoprim (160 mg)-sulphamethoxazole (800 mg) (TMP-SMX) twice daily. Haemophilus ducreyi was isolated from the ulcer in 57 patients (33 men and 24 women). 16 patients were subsequently diagnosed serologically as having syphilis. No aetiological diagnosis was made in 40 patients. Treatment with sulphamethoxazole failed in five of 21 (24%) culture positive patients who were available for evaluation after seven days, whereas all 19 of such patients who were treated with TMP-SMX responded to treatment. Of the 21 isolates available for susceptibility testing, all were susceptible to trimethoprim alone (MIC less than 0.5 mg/l) and three were resistant to sulphonamides, all three containing a 4.9 megadalton (Mdal) plasmid. Two of the three patients from whom these isolates had been obtained were treated with sulphamethoxazole and both were clinical and bacteriological failures. Five of six patients with sulphonamide-susceptible H ducreyi responded to treatment with sulphamethoxazole. Failure of sulphonamides to eradicate H ducreyi in some patients with chancroid is associated with the presence of a sulphonamide resistant plasmid. In regions where this plasmid is present in H ducreyi TMP-SMX is the preferred treatment for chancroid.

Antimicrobial therapy of chancroid: an evaluation of five treatment regimens correlated with in vitro sensitivity

One hundred fifty-one men with genital ulcer disease were assigned randomly to treatment with one of five oral antimicrobial regimens: (1) sulfadimidine (1 g four times daily for seven days); (2) tetracycline (500 mg four times daily for seven days); (3) trimethoprim-sulfamethoxazole (TMP-SMZ; 160 mg of TMP and 800 mg of SMZ twice daily for seven days); (4) doxycycline (300 mg as a single dose); or (5) TMP-sulfametrole (640 mg of TMP and 3,200 mg of sulfametrole once as a single dose). Haemophilus ducreyi was isolated from 81 (54%) of the men, and 35 strains were available for testing of antimicrobial susceptibility. The TMP-SMZ and TMP-sulfametrole regimens were more effective than sulfadimidine, tetracycline, or single-dose doxycycline in curing ulcers. Only one of 35 strains tested was susceptible to tetracycline (less than or equal to 8 mg/liter), and only ten of 35 strains were susceptible to doxycycline (less than or equal to 4 mg/liter), whereas all were susceptible to trimethoprim (less than or equal to 2 mg/liter). The correlation between in vitro susceptibility and bacteriologic response to the antimicrobial agents requires further investigation. In particular, sulfonamide resistance did not always identify failure to respond to sulfadimidine.

Treatment of chancroid by clavulanic acid with amoxycillin in patients with beta-lactamase-positive Haemophilus ducreyi infection

Multiresistant strains of Haemophilus ducreyi, the aetiological agent of chancroid, are prevalent in Nairobi, Kenya, where tetracyclines and sulphonamides are no longer very effective in the treatment of chancroid. The following regimens (given three times daily for seven days) were compared in a double-blind randomised trial--amoxycillin 500 mg, amoxycillin 500 mg and clavulanic acid 125 mg, and amoxycillin 500 mg and clavulanic acid 250 mg. 68 of 100 ulcers were culture-positive for H. ducreyi. All strains of H. ducreyi produced beta-lactamase. At day 7 none of the amoxycillin-treated patients had responded clinically or bacteriologically, whereas all but 2 of 56 patients treated with an amoxycillin/clavulanic-acid regimen had responded clinically and H. ducreyi had been eradicated from their ulcers. The combination of amoxycillin-clavulanic acid appears to be very effective for the treatment of chancroid. The results of this study accord with H. ducreyi as the primary pathogen of chancroid.

Genital ulcers in Kenya. Clinical and laboratory study

Of 97 patients with genital ulcers attending a special treatment clinic in Nairobi, Kenya, 60 harboured Haemophilus ducreyi, four herpes simplex virus, and five Neisseria gonorrhoeae. Eleven patients had serological evidence of syphilis; of these one case was confirmed by darkfield microscopy. In the remaining cases no aetiological agent was identified. An enriched chocolate agar with vancomycin and serum was a useful medium for primary isolation of H ducreyi. Tetracycline was generally ineffective in the treatment of ulcers, but sulfadimidine was successful in almost 80% of cases.