Epidemiological features of women with trichomoniasis in. Auckland sexual health clinics: 1998-99. Min Lo, Murray Reid and Michael Brokenshire. Abstract.
THE NEW ZEALAND MEDICAL JOURNAL Vol 115 No 1159
ISSN 1175 8716
Epidemiological features of women with trichomoniasis in Auckland sexual health clinics: 1998-99 Min Lo, Murray Reid and Michael Brokenshire Abstract Aim To determine some epidemiological features of female sexually transmitted disease (STD) clinic attendees with Trichomonas vaginalis infection. Methods A retrospective audit of patient charts was performed on all cases of T. vaginalis infection diagnosed in female patients in an 18-month period from January 1998 to June 1999 (n=88). Descriptive features of these cases were collated. The ethnicity of female patients with T. vaginalis was compared to that of all other female attendees within the same period. Results The incidence of T. vaginalis infection was 2.2% in 1998–1999. The mean age of patients was 26.5 years. Maori and Polynesian women were over-represented. Overall, patients were more likely to be symptomatic at presentation (78%) and to have abnormal findings on clinical examination (81%). 28% had co-existing chlamydia infection and 10% had co-existing gonorrhoea infection. Conclusions The mean age of 26.5 years is lower than that quoted in other studies. The majority of patients had more than one condition at diagnosis. The rate of coinfection with chlamydia is high and some consideration could be given to empirical treatment of chlamydia in patients diagnosed with T. vaginalis infection. Trichomoniasis is a common, sexually transmitted disease caused by the flagellated protozoan parasite T. vaginalis.1 The World Health Organisation has estimated that 180 million infections are acquired annually worldwide.2 Data from prevalence studies have often been based on clinic, rather than community populations and may vary depending on the type of diagnostic method used. Estimates for North America are between five and eight million new infections each year, with a rate of asymptomatic cases as high as 50%.3,4 A recent study of 361 women at Baltimore City Health Department STD Clinic found trichomoniasis to be the most common STD identified with a prevalence of 24%.5 Women of lower socio-economic groups are at highest risk in both developing and developed countries.6 The prevalence may be as high as 50% in women in the developing world and in minority groups in industrialized populations.6 In rural South Africa, 65% of pregnant women attending an antenatal class in 1981,7 and 41% in 1999,8 were reported to have been infected. Among Australian Aboriginals, 17% were positive for trichomoniasis, while fewer than 1% of non Aboriginals were infected.9 Trichomonal infection ranges from an asymptomatic carrier state to profound, acute, inflammatory disease.1 Risk of complications is small. Complications include
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premature labour and low birth weight.7,10 T. vaginalis infection is also associated with a small increase in relative risk for HIV transmission where HIV co-infection exists.11 While this is of minor importance in populations with low T. vaginalis prevalence, the attributable risk is substantial in endemic populations.6 Methods Auckland Sexual Health Service (ASHS) is the public STD service for the Auckland sub region, which contains the largest metropolitan area in New Zealand with a combined population of 1 193 000.12 ASHS has four separate clinical facilities serving a mixed client base including young heterosexuals, gay men and women, migrant and local sex workers, travellers, and injecting drug users. Combined, the four sexual health clinics have approximately 4000 female attendances each year. In the period January to December 1999, approximately 3598 new female presentations occurred (new patients or previous patients returning with a new problem) and 86 cases of trichomoniasis were diagnosed. These represented 2.4% of the total case-load. Study period and collection of patients A computerized database was used to list all female patients attending with T. vaginalis infection. Data were collected by clinical record review from 88 patients with trichomoniasis attending in the 18-month period from January 1998 to June 1999. Database counts, by ethnicity, were obtained of all other female patients attending in the same period. Patients with repeat infections and those who had been referred for treatment by primary care providers were excluded from the study. For this audit by an ASHS clinician, Auckland Ethics Committee involvement was not required. Screening of patients Standard specimen collection techniques were used during the routine genital examination to screen for sexually transmitted infections (STIs). Testing for STIs included: vaginal pH measurement; cervical and vaginal swabs for gram stain analysis; vaginal wet film microscopy for yeast, trichomonas, bacterial vaginosis; cervical and urethral swabs for gonorrhoea culture and chlamydia; and vaginal swabs for yeast culture. Diagnosis of T.vaginalis Cotton tipped swab specimens were taken from the posterior vaginal fornix for direct wet film microscopy and culture, using Modified Diamonds TYM (trypticase, yeast, maltose) broth. The microscopy was performed within ten minutes of collection by trained laboratory staff on site. The culture broth was incubated at 36 °C for two to three days and then examined by wet film. Patient data The following information was obtained from the patients’ notes and recorded on a standard proforma: age, self-identified ethnicity, number of partners in the previous three months, use of contraception, use of condoms, symptom status at presentation, signs on clinical examination, coexisting chlamydia and/or gonorrhoea infection, treatment prescribed, compliance with therapy and outcome of contact tracing. Statistical analysis Data were tabulated and frequencies calculated using SPSS. Odds ratios (OR) were calculated using Epi-Info 6.04d software.13
Results Characteristics of the study population are shown in Table 1. Ethnicity of the study population compared to female clinic attendees is shown in Table 2. Symptoms at presentation and clinical signs on examination are shown in Table 3. The majority of women were either symptomatic at presentation (78%) or had some degree of abnormal findings on clinical examination (81%). Vaginal discharge was the most common clinical finding, in 42/88 (48%) of cases. Vaginal pH was elevated above pH 6.0 in 50% of cases. Rate of co-infection is shown in Table 4. 86% of women had more than one diagnosis (76/88), while only 13% (12/88) had trichomoniasis as their only diagnosis. The prevalence of co-infection with chlamydia and gonorrhoea was 28% and 10% respectively.
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Table 1. Incidence of T. vaginalis cases by patient characteristics Factor
Number of cases (%) n=88
Age Group 13-15 16-19 20-24 25-29 30-34 35-44 45+ Partners in previous 3 months 0 1 2 >3 Use of contraception None Condom Oral Depot IUCD Sterilisation Use of condoms None Inconsistent Consistent Not recorded
6 (7) 12 (13) 18 (20) 20 (23) 13 (15) 15 (17) 4 (4) 2 (2) 51 (58) 11 (12) 16 (18) 47 (53) 16 (18) 12 (14) 5 (6) 4 (5) 4 (5) 59 (67) 15 (17) 13 (14) 1 (1)
Table 2. Ethnicity of T. vaginalis patients compared with female clinic attendees Ethnic group
Female patients with T. vaginalis infection (%) n=88 Caucasian 19 (22%) Maori 40 (46%) Pacific Island 18 (21%) Asian 5 (6%) Other 1 (1%) Not recorded 5 (6%) NS = not statistically significant
Total Female Clinic Attendees, Jan 98 to June 99 (%) n=7326 5168 (70%) 920 (12.5%) 438 (5.9%) 614 (8.3%) 159 (2.1%) 27 (0.3%)
OR
95%CI
p-value
0.11 6.00 4.16
(0.06, 0.19) (3.84, 9.36) (2.37, 7.23)
