Syphilis, a chronic multistage disease caused by the spirochete Treponema pallidum subspecies pallidum,is usual transmitted by sexual contact or through the placenta during pregnancy1. Syphilis infection remains a serious public health problem worldwide, with a global prevalence of an estimated 36 million cases and an annual incidence of 12 million cases. According to the World Health Organization (WHO), pregnant women with active syphilis will suffer stillbirth or the neonates contract the infection or die in the perinatal period in half of these cases2. Syphilis is among the five most reported infectious diseases worldwide and is the most frequently reported sexually transmitted infection (STI) in Brazil. Sexually transmitted infections in the adult population are estimated at 937,000 cases per year, with a prevalence of 2.6% (range: 1.0% to 4.4%). Because gestational syphilis is often not treated properly, it is a major cause of stillbirth with approximately 2.65 million cases attributed to this disease every year3. The infection results in the formation of lesions that occur particularly in the genital area. Syphilis may also facilitate the transmission of human immunodeficiency virus (HIV) and appears to increase the risk of contracting HIV by up to 4 times4.
Brazil has reached an alarming transmission rate of syphilis in the susceptible population, with 21,382 cases in pregnant women and 13,705 cases in children <1 year of age reported in 2013 by the Information System on Diseases of Compulsory Declaration (SINAN), a public health notification system. In this report, the Midwest region had one of the highest syphilis rates in pregnant women in the country (8.5 cases in 1,000 live births)5 and within this region, the state of Mato Grosso do Sul had the most cases in 2015 (21.9 cases in 1,000 live births)2. Although cases of congenital, gestational, and acquired syphilis have been reported in Brazil since 1986, 2005, and 2010, respectively, few studies have evaluated these notifications in recent years. Therefore, the aim of this study was to describe the epidemiological profile of reported syphilis cases in the adult population of Mato Grosso do Sul state. The results of this study will support the implementation of public health strategies to control this infectious disease.
Mato Grosso do Sul is a state with 2.5 million inhabitants in the Western central region of Brazil that borders with Paraguay and Bolivia. The state has implemented 547 basic health facilities that serve 735,479 inhabitants. Data pertaining to syphilis notification documented between January 2013 and December 2014 in the SINAN of Mato Grosso do Sul was assessed in this retrospective, observational study. Variables collected included age, race, sex, level of education, treatment of patients and partners, serological tests and tests on the liquor (treponemic/non-treponemic), clinical classification, diagnosis of maternal syphilis, case evolution, and clinical manifestations such as changes in the long bones observed by radiology, osteochondritis, cutaneous lesions, jaundice, anemia, splenomegaly, hepatomegaly, and pseudoparalysis. Extracted data was transferred to Excel sheets (Microsoft, Redmond, WA, USA) and analyzed with the Statistical Analysis System (SAS) version 9.2 software (SAS Institute, Cary, NC, USA) using a simple frequency procedure of the reported syphilis cases. The incidence rate of acquired syphilis cases was calculated using population estimates reported for this period by the Fundação Instituto Brasileiro de Geografia e Estatística (IBGE).
In the study period, 2,207 cases of acquired syphilis, 1,497 cases of gestational syphilis and 417 cases of congenital syphilis were reported in the state of Mato Grosso do Sul. The incidence rate of acquired syphilis was 88 cases/100,000 inhabitants, representing 2.4% of all patients reported nationwide2. Of these patients, 36% were older than 40 years, 59% were men, 39% were of mixed race, and 45% were only educated up to primary school (Table 1). Unfortunately, certain clinical characteristics of these patients such as duration of treatment, sexual behavior, and socio-demographics, could not be evaluated because this information had not been provided with the notification.
TABLE 1: Demographic characteristics of patients with acquired syphilis reported between January 2013 and December 2014.
| Variables | Cases | % |
|---|---|---|
| Number of syphilis | 2,207 | |
| Gender | ||
| Male | 1,311 | 59 |
| Female | 895 | 40 |
| Undefined | 1 | 0.05 |
| Race | ||
| White | 574 | 26 |
| Black | 98 | 4 |
| Asian | 19 | 1 |
| Mixed | 851 | 39 |
| Indigenous | 34 | 1 |
| Data missing | 631 | 29 |
| Age | ||
| ≤19 | 214 | 9 |
| 20-29 | 688 | 31 |
| 30-39 | 481 | 22 |
| ≥40 | 806 | 36 |
| Data missing | 18 | 0.8 |
| Schooling | ||
| Illiterate | 23 | 1 |
| Primary | 990 | 45 |
| Secondary | 88 | 4 |
| Data missing | 1,106 | 50 |
Out of 1,497 patients with gestational syphilis, 48% were between 20 and 29 years old, 51% were of mixed race, and 71% had only completed primary education. The disease was diagnosed during the primary stage in 36% of these cases, followed by 22% in the tertiary stage and 11% in the latent stage. Nonetheless, only 71% of these patients were properly treated with 7.2 million IU of penicillin G and only 50% of the sexual partners received concurrent treatment (Table 2). Of the patients with congenital syphilis, 52% were boys, with most babies and their mothers being of mixed race (47%/62%). Treponemal and non-treponemal tests were conducted at birth in 37% and 77% of the newborns, respectively. Nonetheless, only 58% of infected newborns had a mother with a confirmed syphilis diagnosis. The most common clinical signs in newborns were jaundice (9%), anemia (3.6%), and changes in the long bones observed in radiological exams (2.64%). Less than 1% of these patients died from syphilis (Table 3).
TABLE 2: Demographic characteristics of patients with gestational syphilis reported between January 2013 and December 2014.
| Variables | Cases | % |
|---|---|---|
| Total cases | 1,497 | |
| Race | ||
| White | 470 | 31 |
| Black | 78 | 5 |
| Asian | 12 | 1 |
| Mixed | 775 | 51 |
| Indigenous | 101 | 6 |
| Data missing | 81 | 5 |
| Age | ||
| ≤19 | 401 | 26 |
| 20-29 | 733 | 48 |
| 30-39 | 345 | 22 |
| ≥40 | 37 | 2 |
| Data missing | 1 | 0.06 |
| Schooling | ||
| Illiterate | 17 | 1 |
| Primary | 1,083 | 71 |
| Secondary | 23 | 1 |
| Data missing | 394 | 26 |
| Treponemic test reagent | ||
| Reagent | 1,115 | 73 |
| Unrealized | 236 | 15 |
| Data missing | 166 | 12 |
| Non-treponemic test | ||
| Reagent | 1,163 | 77 |
| Non-reagent | 106 | 7 |
| Not performed | 172 | 11 |
| Data missing | 76 | 5 |
| Clinical classification | ||
| Primary | 518 | 34 |
| Secondary | 68 | 5 |
| Tertiary | 316 | 21 |
| Latent | 158 | 10 |
| Data missing | 457 | 30 |
| Treatment | ||
| Penicillin G 2.400.000UI | 289 | 19 |
| Penicillin G 4.800.000UI | 28 | 1 |
| Penicillin G 7.200.000UI | 1,054 | 70 |
| Another antibiotic | 20 | 1 |
| Not treated | 72 | 5 |
| Data missing | 54 | 4 |
| Sexual partner treatment | ||
| Treated | 756 | 50 |
| Not treated | 528 | 35 |
| Data missing | 233 | 15 |
TABLE 3: Demographic characteristics of patients with congenital syphilis reported between January 2013 and December 2014.
| Variables | Cases | % |
|---|---|---|
| Number | 417 | |
| Gender | ||
| Male | 218 | 52 |
| Female | 190 | 45 |
| Undefined | 9 | 2 |
| Race | Son/Mother | |
| White | 154/101 | 37/24 |
| Black | 7/17 | 1/4 |
| Asian | 1/0 | 0.2/0 |
| Mixed | 195/260 | 47/62 |
| Indigenous | 21/28 | 5/7 |
| Data missing | 39/11 | 9/2 |
| Diagnosis of maternal syphilis | 245 | 58 |
| Treponemal confirmatory test at birth | 156 | 37 |
| Non-treponemal test at birth | 328 | 77 |
| Non-treponemal test | Blood/Liquor | |
| Reagent | 295/8 | 71/1.9 |
| Non-reagent | 62/110 | 15/26 |
| Not performed | 39/231 | 9/55 |
| Data missing | 21/68 | 5/16 |
| Clinical manifestations | ||
| Changes in long bones (radiological tests) | 11 | 2.6 |
| Osteochondritis | 5 | 1.2 |
| Cutaneous lesions | 9 | 2.1 |
| Jaundice | 40 | 9 |
| Anemia | 15 | 3 |
| Splenomegaly | 5 | 1.2 |
| Hepatomegaly | 8 | 1.9 |
| Pseudoparalysis | 2 | 0.48 |
| Case evolution | ||
| Alive | 355 | 85 |
| Death by syphilis | 4 | 0.96 |
| Death by another cause | 6 | 1.4 |
| Abortion | 4 | 0.96 |
| Stillborn | 13 | 3 |
| Data missing | 35 | 8 |
The “great imitator” syphilis is still a serious concern for the sexually active population in the Midwest region of Brazil. In this retrospective, observational study, data from 2,207 adult patients with acquired syphilis, 1,497 women with gestational syphilis, and 417 children with congenital syphilis were collected. Our study showed an increase in gestational syphilis by 1,265 cases in the assessed region within the last decade6. A similar increase has been reported for other states but Mato Grosso do Sul had the highest incidence rate (16.7 cases/1,000 live births).2
Although the guidelines from the Brazilian Ministry of Health recommend a medical follow-up of the sexual partners of STI patients of the preceding 3 months7, half of the partners of pregnant women with syphilis were not treated according to our findings. This could potentially result in re-infections and additional cases of latent syphilis and demonstrates the inadequacy of public health programs. Furthermore, 58% of mothers whose sons were born with congenital syphilis had been diagnosed with gestational syphilis. This may indicate either a lack of appropriate treatment of the mother or a failure of the employed treatment regimen and the prenatal follow-up. In addition, social and behavioral risk factors may be associated with gestational syphilis and therefore more studies are needed to identify the reasons for the failure to control syphilis in pregnant women.
There is clear evidence that intra-uterine transmission to children and the ensuing adverse outcomes could be avoided by simple and cheap interventions performed by any physician at a primary care clinic8,9. Furthermore, 90% of the treated mothers received penicillin G, thereby decreasing the chance of adverse outcomes for the fetus. Our results also revealed that patients with acquired and gestational syphilis (45% and 71% respectively) had a low level of education which has been linked to unprotected sexual practices in previous studies10,11. Of note, teenagers tend to have the first sexual experience during the years at primary school12, indicating the need for sexual education in primary school. These observations are corroborated by similar reports on low educational levels and required treatment of sexual partners among syphilis patients in Olinda (Pernambuco state)13, Belo Horizonte (Minas Gerais state)14, and Sumaré (São Paulo state)15. Preventive interventions and sexual education on potential risks of transmission associated with sexual practices would encourage this population to practice safer sexual behaviors.
We assessed syphilis notifications of 2 years only which prevented statistical analysis of the data obtained in this study. Despite this, data on patients with acquired syphilis missing in the SINAN files such as serological tests and socio-demographic characteristics could be identified. The results of our study highlight the shortcomings of the basic health system and point to a substantial revision of practices to manage and prevent syphilis and other STIs. These may include counseling for risk reduction, increased access to condoms, and frequent testing for syphilis, particularly targeting socioeconomic groups that are at higher risk.
In conclusion, this study revealed a substantial increase in new syphilis cases in this part of Brazil. Furthermore, our results demonstrate that most cases of congenital syphilis could be avoided by effective treatment of the pregnant mother and her partner. Thus, public health strategies to prevent and manage syphilis infections need to be reviewed and improved.
