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| ABSTRACT |
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| INTRODUCTION |
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Nicaragua has seen some changes in the last two decades that might indicate that there will be an increase in the prevalence of HIV in the future: increased prevalence of syphilis, increased mobility, and increased commercial contacts. In Nicaragua, there is no mandatory HIV testing for pregnant women, nor is there counseling to recommend an HIV test. Testing for syphilis, however, is mandatory in the first trimester of pregnancy.
The goal of this prevalence study was to determine the prevalence of HIV and syphilis and to identify risk factors among pregnant women visiting antenatal clinics (ANCs) in a medium-sized city in west Nicaragua. Such information will provide insight into the circulation of sexually transmitted diseases (STDs) in general.4
| MATERIALS AND METHODS |
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Study population. All pregnant women attending the "emergencia gynaecologia" of the Hospital Escuela Oscar Darilo Rosales Arguello (HEODRA) or one of three ANCs in León were invited to participate in the study, as were all women who had given birth in the previous 24 hours in the HEODRA hospital. The latter group visited the hospital for prenatal care in earlier months. Women who had already participated in this study were excluded.
Non-responders. Reasons for refusal were recorded.
Clinical methods. Women gave their written informed consent after they received information about the study. Demographic and sexual/reproductive data and information about risk factors for STDs and blood-borne infections were collected by means of an interview questionnaire. Blood samples were collected, and serum samples (in duplicate) were stored at -20°C at the laboratory of the HEODRA hospital before being sent to the Department of Virology of the Eijkman-Winkler Institute of the UMC Utrecht, Utrecht, The Nether-lands, for testing for antibodies to HIV and Treponema pallidum.
Laboratory methods. The sera were tested for HIV antibodies, 24 months after the samples were taken, using the Enzygnost Anti-HIV1/2 Plus test (Dade Behring, Marburg, Germany), which has a sensitivity of > 99% and a specificity of 99.3100%.6 Positive tests were confirmed by immunoblot (Inno-Lia HIV confirmation; Innogenetics, Gent, Belgium). Testing for antibodies against T. pallidum was carried out with an automated inhibition ELISA (Enzygnost; Dade Beh-ring) with a sensitivity of 98.4100% and a specificity of 99.5% for pregnant women.7 The presence of syphilis was confirmed with treponema pallidum haemagluttination assay (TPHA) (Fujirebio, Tokyo, Japan) and venereal diseases research laboratory (VDRL) (Abbott Murex, Dartford, UK), but only when ELISA results were borderline or positive. A positive reaction in ELISA, TPHA, and VDRL was considered indicative of recent and/or active T. pallidum infection. If the ELISA result was borderline and the TPHA and VDRL remained negative, it was concluded that there was no T. pallidum infection. If the ELISA was positive but the TPHA and VDRL were negative, immunoblotting was performed to confirm or rule out T. pallidum infection. A positive ELISA in combination with a positive TPHA or a positive VDRL was considered indicative of (treated) recent T. pallidum infection or T. pallidum infection in the past.
Data analysis.
The data were entered and analyzed using SPSS version 10 for windows (SPSS Inc., Chicago, IL). Descriptive statistics were used to determine the occurrence of HIV and syphilis. To identify potential risk factors, univariate relative risks and odds ratios with associated 95% confidence intervals, and significance levels were evaluated using the Pearsons
2 test and the Fisher exact test. Because of the low number of outcomes for T. pallidum infection (N = 16), multivariate analyses were not performed.
Follow-up. The participants were invited to return for their test results after 3 months. At this point, they also received counseling on how to prevent HIV and syphilis. The women who were infected with syphilis were contacted; they received free treatment and follow-up.
| RESULTS |
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Fourteen women reported that they had had a genital ulcer, 559 that they had or had had vaginal discharge, 14 that they had or had had genital warts, and 8 thought that they had or had had syphilis; 1 woman thought that she was infected with HIV. More than one half of the women (634; 59.9%) had been given an injection in the past 12 months, in most cases, it was a tetanus vaccination in the context of the pregnancy. None of the women reported ever having used intravenous drugs. Four women had or had had commercial sex and 75 women had had a blood transfusion in the past.
HIV prevalence. None of the women tested were HIV positive (prevalence, 0%; 95% CI = 0.00.3).
Syphilis prevalence.
Sixteen women (1.5%) had evidence of recent or past T. pallidum infection. The univariate associations between T. pallidum infection and demographic characteristics are given in Table 1
: illiteracy and primary school education only (relative risk [RR] = 5.7; 95% CI = 1.62.0) and two or more pregnancies (RR = 5.3; 95% CI = 1.914.6) were associated with T. pallidum infection; there was a trend for commercial sex (P = 0.059), and there seemed to be a trend for age between 21 and 30 years (P = 0.076).
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| DISCUSSION |
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Possible limitations of this study, such as the number of women included, the non-responders, and the theoretical possibility of a lower sensitivity and specificity of the laboratory tests caused by transport and processing of the samples, must be discussed before the data can be interpreted. This study has a 95% confidence interval of 0.00.3%. The estimated HIV prevalence in Nicaragua of 0.2% is contained within this interval, which implies that this study performed in 1,000 women will yield a result that is sufficiently close to the expected prevalence. Approximately 90% of the invited study population agreed to participate. We do not suspect that the non-responders had a higher risk of being HIV positive. Reasons for refusal were plausible, and although we do not have data to prove it, demographically, the groups did not seem to differ. There was no apparent participation benefit for the women that might have contributed to non-response as well. Furthermore, the WHO states that refusal may be associated with either higher or lower risk of HIV infection and that it is therefore difficult to draw general conclusions on the strength of the association between refusal and HIV prevalence.10 The probability that the storage, transport, and processing of the samples led to a lower sensitivity and specificity of the HIV tests is very small because, whereas HIV antibodies were not detected, T. pallidum antibodies were. This suggests that the condition of the samples had not deteriorated during transportation. The assays used were reliable and the samples were adequately stored.
Although it was not possible to determine a risk profile for HIV infection, it was possible for syphilis. Unexpectedly, the number of sexual partners a woman had was not a risk factor. This might be explained in two ways. The first explanation might be that women did not answer the question concerning their total number of sexual partners truthfully because of socially desired behavior. Moreover, the "machismo" culture of Nicaragua may make it difficult for women to admit to having several partners.8 Although we encouraged participants to have a face to face interview, they were allowed to be interviewed in the presence of others, if needed. Second, the women could have been infected by their steady partner; the number of partners and behavior of the womens partner could be more important than the number of partners of the woman herself.11 Earlier research has shown that, in 2003, a housewife in Chinandega had a two times higher chance of being infected with HIV than a prostitute.4 Moreover, one half of Nicaraguan women believe that their husbands have extramarital sex.8
Physical signs of STDs, such as leukorrhea, genital warts, or ulcers, were also not associated with T. pallidum infection. This may have been because we used self-reported data and thus the data may not be entirely reliable.
Although we found no HIV infection in the women, we know the virus is circulating in the population in Nicaragua and León. Of ~400,000 people who annually visit the hospital and clinics of León, 45 are being treated for AIDS at the time of writing.12,13 A possible explanation for why we did not find any infection in this group of women is population selection bias: women who visit ANCs may pay more attention to their health and may have different socio-economic characteristics than women who do not visit ANCs.14 Moreover, there are indications that HIV-positive women are less fertile than HIV-negative women, and thus may be excluded from such a research population.14 Last, from data already collected, it seems that, in Nicaragua, as in most (non-African) countries, HIV infection is concentrated and more prevalent among specific risk populations and in specific risk places. UNAIDS reported a HIV prevalence of 9.3% among homosexual men in the capital Managua in 20012002.15 Most AIDS cases in Nicaragua are also reported in this city.4
The prevalence of syphilis seems to have increased since 2000 in Nicaragua, possibly indicating an increase in STDs such as HIV. Several risk factors that increase STD transmission, such as variable sexual contacts, low use of condoms, and increased mobility of the population, are present in Nica-ragua. It is difficult to estimate the proportion of people in León who have multiple sexual contacts. It seems that people start having sex at a young age and have multiple sexual relationships, even during marriage. There has been no research on this, apart from the above-mentioned study that one half of the Nicaraguan women believe that their husbands have extramarital sex.8 The use of condoms in both stable and unstable sexual relationships is low: in 19962002, only 17% of the Nicaraguan women 1524 years of age reported using a condom.8,16 Furthermore, the mobility of the Nicaraguan population has increased during the past 20 years because of war, socio-economic crises, and natural disasters. The improved economic situation of the last 10 years has increased commercial contacts with neighboring countries, which in turn has increased cross-country transport. These developments may mean that there will be a sharp increase in the prevalence of HIV in the future.
Prevention of the transmission of HIV/AIDS among the Nicaraguan population requires national acknowledgment of the threat that the virus poses, adequate training of medical workers, education of the population regarding the prevention of STDs, the promotion of condom use (even the distribution of free condoms), and free HIV testing. Reliable information about the occurrence of HIV/AIDS in Nicaragua is needed. Follow-up studies of women who visit ANCs in León, Nicaragua, should take special effort to limit the amount of self-reported data. It would also be worthwhile to study the prevalence of HIV/AIDS among specific populations, such as blood donors or students, or high-risk populations, such as homosexuals, intravenous drug users, or prostitutes.
In conclusion, it can be stated that HIV does not seem to be highly prevalent among pregnant and postpartum women in León. The higher proportion of women infected with syphilis than found in earlier studies suggests that sexually transmitted diseases are circulating in the general population and highlights the increasing importance of HIV prevention.
Received October 20, 2005. Accepted for publication April 7, 2006.
Financial support: This study was supported by the Nederlandse Ve-reniging van AIDS Behandelaren (NVAB)/Dutch Association of physicians in AIDS.
* Address correspondence to I. M. Hoepelman, Professor in Medicine, Infectious Diseases Specialist, Department of Internal Medicine and Infectious Diseases, University Medical Centre, PO Box 85500, F02.126 3508 GA, Utrecht, The Netherlands. E-mail: I.M.Hoepelman{at}umcutrecht.nl ![]()
The first two authors each contributed equally to this manuscript. ![]()
Authors addresses: C.E.L. Hoekstra, Department of Otorhinolaryngology, H02 102, University Medical Center, Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands. M. Riedijk, Eijkman Win-kler Center for Microbiology, Infectious Diseases and Inflammation, Rm. G04, 614 Heidelberglaan 100, 3584 CX, Utrecht, The Nether-lands. A. J. Matute, Department of Internal Medicine, HEODRA University Hospital, UNAN, León, Nicaragua. E. Hak, University Medical Center, Utrecht Julius Center for Health Sciences and Primary Care, PO Box 85500, 3508 GA Utrecht, The Netherlands. E. Delgado, Department of Internal Medicine, HEODRA University Hospital, UNAN, León, Nicaragua. R. E. Alonso, Microbiology Laboratory, HEODRA University Hospital, UNAN León, Nicara-gua. M. D. Benavides, Department of Gynecology and Obstetrics, HEODRA University Hospital, UNAN León, Nicaragua. A. M. van Loon, Department of Virology G04.614, University Medical Centre, Utrecht Heidelberglaan 100, 3584 CX Utrecht, The Netherlands. I. M. Hoepelman, Department of Internal Medicine and Infectious Diseases, University Medical Centre, Utrecht, The Netherlands.
| REFERENCES |
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Plus; reference number OQFK 613, 2-g.
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