Gender differences in sexual behaviours in response to genitourinary symptoms.

OBJECTIVE: To understand gender differences in sexual behaviours in response to genitourinary symptoms. METHODS: 473 (239 female and 234 male) subjects were enrolled at an STD clinic regardless of symptoms or infection status. Subjects completed a 30 day calendar recall interview of genitourinary symptoms, coital activity, sexual partners, and condom use. RESULTS: Of the total of 473 participants, 261 (55%) reported symptoms (61% women and 39% men). STI prevalence was 73% and 75% for symptomatic women and men, respectively. For black women the probability of coitus was decreased in the presence of vaginal discharge (OR 0.64, 95% CI 0.47 to 0.89). No change in coital activity was seen in non-black women in the presence of vaginal discharge. Having vaginal discharge did increase the likelihood of condom use by their partners (OR 2.48, 95% CI 1.05 to 5.88), if coitus occurred. Urethral discharge was not associated with coitus or condom use in men. However, in men, dysuria was associated with increased likelihood of condom use (OR 4.25, 95% CI 1.57 to 11.56) if coitus occurred. CONCLUSION: Black women altered both coital activity and condom use behaviours in response to vaginal discharge. In contrast, non-black women did not modify coital activity. Men increased condom use when having dysuria but did not alter coital activity. Changes in sexual behaviours may alter the risk of STI transmission independent of interactions with the healthcare system. STI education and prevention programmes need to better understand these gender and racial differences in developing effective strategies to reduce STI transmission.

Evaluation of the Digene Hybrid Capture II Assay with the Rapid Capture System for detection of Chlamydia trachomatis and Neisseria gonorrhoeae.

Screening for chlamydial and gonococcal infection has been strongly recommended for all sexually active women under the age of 26. Advances in the ability to detect infection by nucleic acid detection techniques have improved access to screening methods in routine clinical practices. To meet the increasing demand for testing, a high-throughput system is desirable. We evaluated the performance of the Hybrid Capture 2 CT/GC (HC2) assay with the Digene Rapid Capture System (HC2-RCS). The results of HC2-RCS for endocervical samples from 330 women were compared to those of culture and the COBAS Amplicor PCR. For detection of chlamydial infection, HC2-RCS had a sensitivity and a specificity similar to those of PCR (P > 0.5) and an improved sensitivity compared to that of culture (P = 0.007). For identification of gonococcal infections, all assays performed similarly (P > 0.5). The performance of HC2-RCS was also compared to that of the manual HC2 format (HC2-M) with these samples and with 911 endocervical samples collected previously. The performance of HC2-RCS was equivalent to that of HC2-M; the overall concordance rates for the detection of chlamydia and gonorrhea were 99.7% (kappa = 0.97) and 99.8% (kappa = 0.97), respectively. When the HC2 assay was performed with a semiautomated system application designed for high throughput, it demonstrated high sensitivity and a high specificity for detection of both Chlamydia trachomatis and Neisseria gonorrhoeae.

Decrease in expenditures and selected nosocomial infections following implementation of an antimicrobial-prescribing improvement program.

OBJECTIVE: To evaluate changes in antimicrobial use and expenditures and the rates of selected nosocomial infections due to resistant organisms associated with implementation of an antimicrobial-prescribing improvement program. DESIGN: Before-after trial comparing 1992 (pre-program), 1993 (a transition year), and 1994 (after full implementation of the program). SETTING AND PARTICIPANTS: Academic medical center, all patients and physicians. INTERVENTION: An antimicrobial-prescribing improvement program with prior approval requirement for use of restricted agents. MAIN OUTCOME MEASURES: Antimicrobial use and expenditures, rates of selected nosocomial infection marker events. RESULTS: Between 1992 and 1994, there were substantial decreases in antimicrobial use, from 158,107 to 137,364 defined daily doses, and in expenditures from $2,486,902 ($24.01 per patient day) to $1,701,522 ($18.49 per patient day). After adjusting for changes in purchase prices and census days, we estimated savings attributable to the program of $279,573 in 1993 and $389,814 in 1994. In addition, we found significant decreases between 1992 and 1994 in the rates of enterococcal bacteremia (.34 vs .16 events per 1,000 patient days; P = .016), selected gram-negative bacteremia (.26 vs .11; P = .015), methicillin-resistant Staphylococcus aureus colonization or infection (.66 vs .20; P < .0001), and Stenotrophomonas colonization or infection (.35 vs .17; P = .019). No significant change occurred in rates of nosocomial candidemia or Clostridium difficile toxin-positive diarrhea. Values for 1993 were intermediate between those of 1992 and 1994. CONCLUSION: Implementation of an antimicrobial-prescribing improvement program was associated with substantial savings in antimicrobial use and expenditures and significant decreases in rates of selected nosocomial infections due to resistant organisms.

Species-, serogroup-, and serovar-specific epitopes are juxtaposed in variable sequence region 4 of the major outer membrane proteins of some Chlamydia trachomatis serovars.

Synthetic peptides and murine monoclonal antibodies were used to map cross-reactive chlamydial epitopes. A species-specific epitope in the central region of variable sequence region 4 abuts the amino-terminal end of a B-serogroup-specific or F/G-serogroup-specific epitope, which in turn abuts known serovar-specific epitopes. The carboxyl-terminal portion of variable sequence region 4 (residues 297 to 314) comprises a region of end-to-end B-cell epitopes in some serovars of the B and F/G serogroups.

The major outer membrane protein of a single Chlamydia trachomatis serovar can possess more than one serovar-specific epitope.

The major outer membrane proteins (MOMPs) of human Chlamydia trachomatis serovars exhibit four regions of variable amino acid sequences (VS1 to VS4) harboring serovar-specific B-cell epitopes. Antibody responses to these epitopes may contribute to acquired protection against human chlamydial infection. MOMP B-cell epitopes defined by 22 different serovar-specific or bispecific murine monoclonal antibodies were localized with synthetic peptides representing the four VS regions of seven genital serovars (D, Da, E, F, G, H, and K). Serovar F possessed two distinct serovar-specific epitopes, located in VS2 and VS4, while serovar K possessed three distinct serovar-specific epitopes, located in VS1, VS2, and VS4. Serovar D- and serovar Da-specific epitopes were located in VS1. Regardless of whether the serovar was from the B (serovars D, Da, and E), C (serovars H and K), or F-G (serovars F and G) serogroup, all serovar-specific epitopes were found in three discrete subgroups of MOMPs. These subregions comprised all central portion of VS1, residues 70 to 77; the amino-terminal half of VS2, residues 139 to 149; and the carboxyl-terminal third of VS4, residues 305 to 315. Monoclonal antibodies to each of these subregions neutralized infectivity in standard HaK cell culture assays. These findings are relevant to the development of an MOMP or MOMP subunit vaccine.

Azithromycin for empirical treatment of the nongonococcal urethritis syndrome in men. A randomized double-blind study.

OBJECTIVE: To evaluate the use of single-dose azithromycin for empirical treatment of nongonococcal urethritis. DESIGN: Randomized, double-blind, multicenter trial comparing azithromycin vs doxycycline therapy, with a 2:1 randomization ratio. Patients were evaluated clinically and microbiologically for Chlamydia trachomatis and Ureaplasma urealyticum infection before therapy and at 2 and 5 weeks after study entry. SETTING: Eleven sexually transmitted disease clinics throughout the United States. PATIENTS: A total of 452 men aged 18 years or older with symptomatic nongonococcal urethritis of less than 14 days' duration. INTERVENTION: Patients were treated with either 1.0 g of azithromycin as a single oral dose or 100 mg of doxycycline taken orally twice daily for 7 days. MAIN OUTCOME MEASURES: Clinical resolution of symptoms and signs of nongonococcal urethritis, microbiological cure of C trachomatis and U urealyticum, and occurrence of adverse experiences. RESULTS: Of the 452 patients enrolled, 248 in the azithromycin-treated group and 123 in the doxycycline-treated group were evaluable for clinical response. The two treatment groups were comparable in terms of age, weight, ethnic distribution, sexual preference, sexual activity, and history of prior nongonococcal urethritis or gonorrhea. Sixteen percent of the azithromycin group and 24% of the doxycycline group were culture positive for C trachomatis before therapy, while 38% and 28%, respectively, were culture positive for U urealyticum. The cumulative clinical cure rate was 81% (95% confidence interval [CI], 75% to 85%) in the azithromycin-treated group and 77% (95% CI, 69% to 84%) in the doxycycline-treated group. Clinical cure rates in the two groups were also comparable when patients were stratified by presence or absence of infection with C trachomatis or U urealyticum prior to therapy. Among those infected with C trachomatis, overall microbiological cure rates were 83% (95% CI, 65% to 94%) for azithromycin-treated patients (n = 30) and 90% (95% CI, 68% to 98%) for doxycycline-treated patients (n = 21). Among those infected with U urealyticum, overall microbiological cure rates were 45% (95% CI, 34% to 57%) for azithromycin-treated patients (n = 75) and 47% (95% CI, 30% to 65%) for doxycycline-treated patients (n = 32). Adverse reactions were generally mild to moderate and occurred in 23% of the azithromycin-treated group and 29% of the doxycycline-treated group. CONCLUSIONS: For empirical treatment of the acute nongonococcal urethritis syndrome in men, a single oral dose of azithromycin was as effective as a standard 7-day course of doxycycline in achieving clinical cure. Further, clinical cure rates were comparable with either regimen, regardless of the presence or absence of Chlamydia or Ureaplasma infection.

Age and clinical immunity to infections with Chlamydia trachomatis.

BACKGROUND AND OBJECTIVES: The prevalence of chlamydial infection decreases with age possibly in part because of increasing immunity. GOAL OF THIS STUDY: To determine whether increased age is an independent predictor of decreased chlamydial infection and whether chlamydia-specific antibody titer and blastogenesis increase with age. STUDY DESIGN: Data from all patients cultured for Chlamydia trachomatis between January 1984 and August 1989 were examined and multiple logistic regression models were used to identify the independent predictors of culture positivity. Antichlamydial antibody titer and chlamydia-specific blastogenesis were examined for a subset of patients for correlation with age. RESULTS: Young age was found to be predictive of chlamydial infection independent of all factors examined in men and women. Antibody titers had no relation to age (n = 245) whereas the level of blastogenesis correlated only weakly with age (n = 155). CONCLUSIONS: Assays of systemic immunity do not reflect the protection from chlamydial infection associated with age.

Partial protection against genital reinfection by immunization of guinea-pigs with isolated outer-membrane proteins of the chlamydial agent of guinea-pig inclusion conjunctivitis.

Because partial protection against reinfection is induced by experimental infection in the guinea-pig model of genital chlamydial infection, we sought to induce immunity by immunization. Female guinea-pigs were immunized subcutaneously with the major outer-membrane protein (MOMP) and the 61 kDa cysteine-rich outer-membrane protein (61 kDa) of the agent of guinea-pig inclusion conjunctivitis (GPIC) eluted from SDS-polyacrylamide gels (SDS-MOMP, SDS-61 kDa). Post-immunization sera and secretions contained antibodies to the SDS-purified proteins at high titre as measured by immunoblotting, whereas enzyme immunoassays (EIA) using whole elementary bodies as antigen showed significantly lower titres (P < 0.001). Likewise, blastogenic responses of peripheral mononuclear cells to GPIC elementary bodies were weak. Animals immunized with SDS-MOMP and SDS-61 kDa were fully susceptible to intravaginal challenge, as were control animals immunized with buffer without protein. Another group of animals were immunized with material prepared by extraction of chlamydial outer-membrane complexes with octyl beta-D-glucopyranoside (OGP) and dithiothreitol, which consisted largely of MOMP (OGP-MOMP). In contrast to the SDS-MOMP group, sera and secretions in the OGP-MOMP group showed high titres in EIA, and high titre antibodies to MOMP by immunoblot; however, most animals also had antibodies to 61 kDa, 72 kDa and ca. 84 kDa outer-membrane proteins. OGP-MOMP animals were partially protected against genital challenge as evidenced by low inclusion scores compared to control animals, although duration of infection measured by culture isolation was similar to controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Recurrent genitourinary chlamydial infections in sexually active female adolescents.

To determine the recurrence rate of chlamydial infections, we initially screened an urban population of 1308 sexually active female adolescents for chlamydial infection at the urethral and endocervical sites; these young women were followed and had additional examinations for infection. Chlamydial infection was documented by tissue culture in 31.1% (407) of them at some time during the study. After appropriate antibiotic treatment, 68.3% (278/407) returned for test-of-cure cultures within 3 months of their initial infection; of those 278, a total of 254 had sterile cultures. These patients were followed to determine the recurrence rate of chlamydial infections. Of these 254 patients, 177 (69.7%) had one or more follow-up visits; 38.4% (68/177) had a recurrent chlamydial infection. The majority of recurrent infections were documented within 9 months of the initial infection. Recurrent infections with the same serovar were frequent, suggesting reinfection by untreated partners or possible relapse of the initial chlamydial infection. This high rate of recurrent infection suggests that female adolescents should be rescreened frequently for genitourinary chlamydial infections.

Ofloxacin versus doxycycline for treatment of cervical infection with Chlamydia trachomatis.

Women with culture-proven Chlamydia trachomatis cervical infection were randomized to receive either ofloxacin (300 mg) or doxycycline (100 mg), orally twice daily for 7 days. All 56 had negative cultures 5 to 9 days after treatment. Four weeks after treatment, 26 (93%) of 28 ofloxacin-treated patients and all 22 doxycycline-treated patients were cured. We conclude that 300 mg of ofloxacin given twice daily for 7 days provides effective therapy for chlamydial infection of the cervix.

A randomized trial to compare 7- and 21-day tetracycline regimens in the prevention of recurrence of infection with Chlamydia trachomatis.

Standard therapy for Chlamydia trachomatis in the United States consists of a 7-day course of tetracycline administration. Recurrent infections are frequent, however, in circumstances in which reinfection seems unlikely, suggesting that the standard regimen may be insufficient to cure the infection. It may reduce the number of organisms, however, below a detectable level at a test-of-cure visit. To evaluate recurrent infection, the authors studied patients with chlamydia who were treated with standard therapy, and they found a recurrence rate of 29% among 2,983 patients who returned to the clinic during a 2-year follow-up period. Recurrent infection was associated with younger age but was not related to either race or gender. To test the hypothesis that a longer treatment course might be more effective in preventing recurrent infection, the authors conducted a randomized trial that compared 7- and 21-day regimens of tetracycline administration. Of the 918 subjects enrolled in the trial, 220 were infected with C. trachomatis. The overall recurrence rate among patients who were infected and returned was 18.4% (9/49) in the 21-day group and 13.8% (8/58) in the 7-day group (P = .60). Similar results were obtained using survival analysis methods. Given the number of subjects who returned, this study had approximately a 65% statistical power to detect a reduction in recurrence rate, from 20% to 5%. Because of the similarity of the results in the two groups, it was concluded that 21 days of tetracycline administration is no more effective in preventing recurrence than 7 days of administration.

Interferon-gamma in endocervical secretions of women infected with Chlamydia trachomatis.

Although interferon-gamma has been associated with control of chlamydial infections in mice, no direct evidence links it to human chlamydial infections. Therefore, interferon-gamma was assayed by ELISA in endocervical secretions and plasma of women cultured for Chlamydia trachomatis. Women with positive endocervical chlamydial cultures had increased levels of interferon-gamma in endocervical secretions (6.7 +/- 2.8, mean +/- SE, n = 47) compared with uninfected women (1.4 +/- 0.4, n = 52) (P = .002). Interferon was also present in secretions of women with gonorrhea. Higher levels were seen in secretions from older women with positive chlamydial cultures. Interferon levels in secretions did not correlate with simultaneous plasma levels, the number of organisms recovered in tissue culture, or clinical correlates of inflammation. These data suggest that interferon-gamma is present at the site of chlamydial infection; however, further experiments are needed to determine whether interferon is specifically involved in protection or is a nonspecific indicator of inflammation.

Immunization against chlamydial genital infection in guinea pigs with UV-inactivated and viable chlamydiae administered by different routes.

Female guinea pigs were immunized with viable or UV light-inactivated chlamydiae (agent of guinea pig inclusion conjunctivitis), belonging to the species Chlamydia psittaci, by intravenous, subcutaneous, oral, or ocular routes. All animals were then inoculated vaginally with viable chlamydiae to determine the extent of protection against challenge infection induced by the various regimens. The course of genital infection was significantly reduced in intensity in all groups of animals except the unimmunized controls and those animals immunized orally with inactivated antigen. Guinea pigs immunized with viable antigen were more likely to develop resistance to challenge infection and, in general, had a significantly greater degree of protection than animals immunized with inactivated antigen. No one route seemed superior in producing a protective response. Animals in all groups demonstrating protection developed serum and secretion immunoglobulin G antibody responses to chlamydiae. Lymphocyte proliferative reactions to chlamydial antigen were variable among groups. Immunoblot analysis of serum and secretions indicated a wide range of antibody specificities, but most protected animals produced antibodies to the major outer membrane protein, lipopolysaccharide, and the 61-kilodalton protein. No definitive associations could be made between the increased ability of immunization with viable organisms to produce resistance to challenge infection and a particular immune parameter. These data indicate that viable chlamydiae given by various routes are able to induce a strong immune response which can provide resistance against reinfection in some cases or at least reduce the degree of infection to a greater degree than inactivated antigen. However, complete resistance to genital tract infection may be difficult to obtain and alternate immunizations strategies may have to be developed.

Histoplasma capsulatum infections of the central nervous system. A clinical review.

Central nervous system manifestations occur in 10 to 20% of patients with disseminated histoplasmosis. Additionally, histoplasmosis may be the cause of cases of chronic meningitis in patients with no other evidence for dissemination. Histoplasmosis may also cause cerebral or spinal cord mass lesions resembling neoplasms or abscesses, and encephalitis. Diagnosis of chronic meningitis or mass lesions caused by H. capsulatum may be difficult and involves careful analysis of serologic tests for antibodies, cultures and tests for HPA in body fluids. Amphotericin B remains the treatment of choice, but relapses occur in half of cases despite total courses of at least 35 mg/kg. Accordingly, careful long-term follow-up is required to identify patients with relapsing infection. Newer antifungal agents which cross the blood brain barrier are needed. A trial of amphotericin B treatment without surgical excision can be justified in patients with cerebral or spinal cord histoplasmomas, in view of the apparent success of such treatment in a few cases. Progression of clinical abnormalities or persistence of the lesion following completion of treatment would support the need for surgical excision.

Efficacy and safety of ofloxacin in the treatment of nongonococcal sexually transmitted disease.

This study compared doxycycline with ofloxacin in the treatment of nongonococcal urethritis in men and mucopurulent cervicitis in women and compared both drugs in the treatment of infections due to Chlamydia trachomatis in both men and women. Informed consent was obtained from all subjects. Eighteen men with nongonococcal urethritis and 12 with previously positive chlamydial cultures were randomly treated with doxycycline or ofloxacin. Eleven women with mucopurulent cervicitis, 14 with a previous positive untreated chlamydial culture, and nine having sexual contacts with men known to have chlamydial urethritis also were randomly treated. Culture specimens for chlamydia were obtained before treatment, five to nine days after therapy (return visit 1), and 21 to 28 days after therapy (return visit 2). Cultures for Ureaplasma urealyticum were obtained only in men. There were no significant differences in results in patients treated with doxycycline or ofloxacin. All but three of 20 men with symptoms were symptom-free on return visit 1 and all were symptom-free on return visit 2. Thirteen women with mucopurulent cervicitis had all resolved at visit 1, although signs of cervicitis reappeared at the second visit in two patients treated with doxycycline and one treated with ofloxacin. All patients with positive chlamydial cultures had negative cultures at the first return visit. One patient treated with doxycycline was positive at the second return visit. Laboratory and clinical abnormalities were mild and did not prevent completion of therapy. These data, together with previous published and unpublished data, indicate that ofloxacin is as effective as doxycycline in the treatment of chlamydial infections. The study also demonstrated that ofloxacin and doxycycline were equally effective in the treatment of nongonococcal urethritis in men and mucopurulent cervicitis in women.

Correlation of infecting serovar and local inflammation in genital chlamydial infections.

The relationship between acute inflammation and serovar of Chlamydia trachomatis was evaluated in patients with genital chlamydial infection who attended a sexually transmitted diseases clinic. Polymorphonuclear leukocytes (PMNLS) were enumerated on Gram's-stained smears of endourethral contents in men; cervicitis was scored by visual observation of the endocervix in women. Isolates were serotyped with a monoclonal antibody-based radioimmunoassay. The distribution of serovars in 99 women did not differ in the presence or absence of cervicitis or concurrent gonorrhea. An overall difference (P = .037) was observed when serovar distributions in men with less than or equal to 3 PMNLs (n = 42), greater than or equal to 10 PMNLs (n = 41), and gonococcal urethritis (n = 42) were compared. Follow-up pairwise comparisons revealed that men with less than or equal to 3 PMNLs had fewer isolates of serovars F and G than did men with greater than or equal to 10 PMNLs (P less than .05). No strong overall association was observed between inflammation and serovar.

Association of recurrent chlamydial infection with gonorrhea.

To determine whether concurrent gonorrhea reactivates latent chlamydial infection, we studied 74 recurrent chlamydial infections and the effect of concurrent gonorrhea at the recurrent episode on the chlamydial serovar identified. Serotyping of 74 recurrent pairs of chlamydial isolates from patients attending a sexually transmitted diseases clinic indicated that 47.1% (16 of 34) with gonorrhea at the time of recurrence harbored chlamydiae of the same serovar as at the initial infection, while only 22.5% (9 of 40) without gonorrhea had the same serovar (P = .03). The proportion of recurrences by the same serovar in the group without gonorrhea did not differ from the proportion predicted by a random exposure model (22.2% vs. 18.4%, P = .46), while the proportion in the gonorrhea group did (47.1% vs. 19.8%, P less than .0001). The possibility of reinfection did not appear more likely in the group with gonorrhea than in the group without. These observations support the hypothesis that concurrent gonorrhea can reactivate latent chlamydial infection.

Role of cell-mediated immunity in the resolution of secondary chlamydial genital infection in guinea pigs infected with the agent of guinea pig inclusion conjunctivitis.

Guinea pigs which have recovered from a genital infection with the agent of guinea pig inclusion conjunctivitis demonstrate strong immunity to reinfection for a short period of time but then become susceptible to reinfection. The secondary infection is markedly shortened in duration and decreased in intensity. Previous studies have indicated an important role for humoral immunity in resistance to and in recovery from reinfection. However, the contribution of cell-mediated immunity to immunity toward or recovery from a secondary infection is not clear. Guinea pigs were infected in the genital tract with guinea pig inclusion conjunctivitis and were challenged at either 30 or 75 days after the primary infection. Prior to challenge, one group of animals were injected with rabbit anti-guinea pig thymocyte serum (ATS) while control groups received either normal rabbit serum or no treatment. Treatment was continued daily for the course of the experiment. On day 30, ATS-treated guinea pigs had a slightly higher rate of reinfection, and generally the infection persisted longer than in controls. On day 75, all animals became reinfected upon challenge, but control animals resolved their infections in 3 to 9 days. In contrast, most ATS-treated animals remained infected throughout the course of the experiment. Although the animals became reinfected, the levels of chlamydiae were much lower than those observed during the primary infection. ATS treatment abrogated T-cell responses, but serum and secretory antibody responses remained normal. Histopathological examination revealed some decrease in mononuclear infiltration of endocervical and uterine tissues in ATS-treated animals. These data indicate that previously infected guinea pigs require both cell-mediated immunity and humoral immunity for resolution of a challenge infection.

Protective role of serum antibody in immunity to chlamydial genital infection.

Female guinea pigs were injected intraperitoneally with pooled immunoglobulin derived from animals immunized to the chlamydial agent of guinea pig inclusion conjunctivitis. Genital infections in animals receiving pooled immunoglobulin from immune animals were markedly decreased with regard to the number of inclusions detected compared with control animals. These data indicated that serum-derived antibody was able to provide a degree of protection against a chlamydial genital tract infection.

Susceptibility to reinfection after a primary chlamydial genital infection.

Female guinea pigs which had been infected genitally with the agent of guinea pig inclusion conjunctivitis were challenged at various times after infection with fresh inocula to determine the duration of immunity resulting from the primary infection. At 30 days after infection, most guinea pigs were resistant to reinfection, as indicated by the inability to isolate chlamydiae from cervical swabs. However, at 77, 155, and 294 days, all animals became reinfected, although the course of the infection was abbreviated and of lower intensity. When various immune parameters were examined, a decrease in antibodies in both serum (immunoglobulin G [( IgG]) and genital secretions (IgA, IgG) was observed after 30 days. A decrease in antibodies to the major outer membrane protein and an 84K component was noted in serum. In genital secretions, IgA antibodies to all major chlamydial components declined markedly after 30 days. Cell-mediated immunity as measured by proliferation of peripheral blood lymphocytes to guinea pig inclusion conjunctivitis antigen also was at a peak response 30 days after infection and decreased thereafter. Thus, loss of complete immunity could not be associated with a particular immune parameter. When genital secretions were examined 14 days after the challenge infection, IgA antibody levels to the lipopolysaccharide and 61K protein components had increased in intensity, whereas other antibodies were relatively low. In addition, complete immunity to a third infection was not increased in duration when animals had recovered from two previous genital infections.