General information

This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Correspondence:

Centro de Ciências Biológicas e da Saúde

Addr.: Travessa Perebebuí, 2623 – Bairro: Marco. Belém, PA, Brasil | CEP 66.087-662

Phone: +55 91 3131-1704

The study was carried out at Universidade do Estado do Pará (UEPA)

Introduction

Syphilis is a constant sexually transmitted infection (STI) and requires compulsory notification. In 2018, according to World Health Organization (WHO), it affected more than 12 million people per year worldwide, and its elimination continues to challenge the health systems of several countries. It should be notified as congenital syphilis, gestational syphilis and acquired syphilis. It was noted that Brazil and its regions showed increased detection rates of acquired syphilis between 2017 and 2018. The increase was 28.3% (from 59.1 to 75.8 cases per 100,000 inhabitants) in the country. Furthermore, growth was 59.3% in Northern Region (from 34.1 to 54.4 cases per 100,000 inhabitants)1.

Syphilis is a systemic infection caused by a spirochete bacterium, Treponema pallidum, transmitted predominantly sexually or vertically. It is an infection that, without or with incorrect treatment, progresses to different phases and latency periods. WHO classifies the disease in early or late syphilis according to the elapsed period from infection to diagnosis2.

Acquired syphilis develops and progresses in three phases: primary, secondary and tertiary. The agent penetrates the mucosa or injured skin and, after the incubation period (21 days), the lesions appear. Initially it is a unique painless papule with a clean bottom, firm and raised edges, classically anogenital, causing primary syphilis3.

Secondary syphilis presents itself as a disseminated mucocutaneous eruption and generalized lymphadenopathy. It usually arises between 2 and 8 weeks after the disappearance of the primary ulcer. The lesions usually begin in the trunk or the proximal extremities as pink macules, which persist from a few days to 8 weeks, evolving into papules and, in some patients, to pustule lesions3.

Tertiary syphilis is a slowly progressive disease that can affect any organ and produce clinical disease 20 to 40 years after initial infection4.

Secondary syphilis occurs in 25% of untreated infected patients. Most lesions are not pruriginous. They can manifest different morphologies at the same time and affect any skin site, especially palms and plants; when affected, strongly suggest the diagnosis. In friction areas, papules can increase, coalesce and corrode, forming moist, painless, and highly infectious plates, called flat condylomas5.

The syphilis diagnosis is performed using serological tests that can be separated into treponemal and non-treponemal.Non-treponemal tests (VDRL and Rapid Plasma Regain - RPR) are nonspecific and can result positive in other diseases, their results are obtained faster, and costs lower. They are widely used in the screening and detection of diseases.Treponemal tests (FTA-ABS, T. pallidum hemagglutination - TPHA) are more specific and sensitive and become positive in the early disease stages; however, they are more expensive. To confirm syphilis diagnosis, both tests, treponemal and non-treponemal, should be used. In secondary syphilis, all antibody-seeking tests are reagents. At this disease stage, it is expected to find elevated titers in non-treponemal quantitative test6.

According to the Brazilian Health Ministry7, the drug of choice for syphilis treatment is benzathine G penicillin. The dose and time between doses depend on disease stages. Alternative drugs are doxycycline and ceftriaxone, which can be used when patients have allergy to penicillin. After the first dose of penicillin, Jarisch-Herxheimer's reaction may occur, characterized by skin lesions exacerbation, with erythema, pain, or itching, which regresses spontaneously after 12 to 24 h, without needing discontinuity treatment. 

In Brazil, according to the Health Ministry Epidemiological Bulletin 20191 the rate of detection of acquired syphilis increased from 34.1 to 75.8 cases per 100.000 inhabitants, from 2015 to 2018. In the Northern region, the total number of cases in 2018 was 9,890 (6.3%), comprising 30.8 cases per 1,000 inhabitants in the Pará state, without underreporting cases. It is considered a public health challenge throughout the country, and since 2010, acquired syphilis is considered a compulsory notification disease.

Syphilis is a disease that often goes unnoticed in its primary phase, which culminates with its late diagnosis. Thus, this study sought to describe the acquired syphilis epidemiological characteristics reported in the state of Pará to better know this disease distribution in the state and to be able to assist coping strategies in the Amazon region. Furthermore, it sought to correlate the disease prevalence in each Pará states mesoregion with their socioeconomic indices.

Methods

Results

Five thousand six hundred twenty cases of acquired syphilis in Pará state occurred during the period analyzed, 1,675 occurred in 2017, 2,591 in 2018, and 1,354 until June 2019. Table 1 shows the predominance of male cases (n = 3,229; 57.45%), young adults aged 18–30 years (n = 2,514; 44.74%) and with elementary school 37.27%. More than half of cases were related to the brown race (n = 4,058; 72.20%), although many ignored cases were detected (11.16%). The distribution of cases was analyzed according to the state's mesoregion, and in the study period, the cases were concentrated in the metropolitan mesoregion of Belém, followed by the Northeast of Pará and Southeast of Pará (Figure 1). The number of cases was higher in 2018, showing more than 511 occurrences in the Northeast of Pará and more than 681 in the metropolitan area of Belém.Table 2 shows the analysis of the prevalence per 1,000 inhabitants in each mesoregion, with the Lower Amazon presenting a result of 103.98 per 100 thousand inhabitants (p < 0.0001) compared to other areas and the state itself.

Discussion

Analyzing the number of syphilis cases acquired in Brazil from 2010 to June 2019, 650,258 cases were reported in SINAN, 4.9% in the North. Between 2017 and 2018, there was an increase of more than 50% in the curve of Brazil and North region, the latter even higher than the national increase1. It is possible to infer that the early diagnosis of the disease is still flawed, mainly because the local health networks present a deficient service to cover all the requirements of a disease classified as a public health problem. This culminates in underreported cases, increased public spending on easily treated or prevented diseases, and inadequate documentation, reinforcing the same statement in other studies10.

Observing each variable in isolation, it was possible to notice marked differences in the disease incidence. Concerning gender, the number of cases remained higher in males; however, from 2017 to 2018, the percentage of growth was higher in females (57%) than males (52%). The higher incidence in males corroborates with a retrospective study conducted in India, in which cases were analyzed for five years11, emphasizing that the pattern of greater involvement in men remains.However, the growth among women can also be attributed to reducing condom use by this group12.

The incidence of the disease was markedly decreased as age advances. From 2017 to 2018, there was a substantial growth of cases in all age groups; however, young adults (18 to 30 years old) still constitute the most prevalent group. According to Garbin et al.10, who also found this age group was predominant, the absence of public sex education policies for the population would contribute to the spread of the disease.

There was a worsening in filling the field concerning race, with 11.15% of ignored notifications. However, the race with the highest prevalence was still brown, accounting for 72% of all cases, according to the Brazilian Institute of Geography and Statistics (IBGE), which states that 72.2% of the northern region population is brown13. According to the Ministry of Health, in 2018, most of the people notified were brown (36.8%), followed by white (36.2%) and black (10.3%)1.

Syphilis, in all its forms of presentation, as an infection predominantly transmitted by sexual intercourse or via maternal-fetal route, is closely related to the country's socioeconomic development. The reflection of the country's development can also be assessed by most of the population's education. The number of disease cases was higher in individuals with low education, with a discrepant ratio compared to individuals with higher education, complete or not. This result corroborates with the data reported in a Chilean study14, in which the highest rates of reported cases were from the least developed regions of the country. Besides, individuals with a lower education level tended to have an even more significant delay in diagnosis. This was mostly due to the lack of information on the subject, which corroborates the largest number of cases1, 15.

Regarding the spatial distribution, there was an alarming number of cases in the metropolitan region of Belém. Regions with large populations may have a large number of cases, but proportionally the Lower Amazon was more prevalent, with a significant increase from 2017 to 2018, even with a population amount considerably smaller than that of the metropolitan region. It is important to emphasize that there is a scarcity of studies related to the locations of the disease cases in Brazil, mainly those aimed explicitly at the prevalence in each state. However, some studies with particular associations help seek an explanatory possibility that explains the differing prevalences.

There are already studies that associate acquired syphilis with sexual habits. However, Souza et al.16 also elucidated the possibility of associating the disease with drug users since they also have sexual habits that favor sexually transmitted infections, such as not using condoms and have multiple partners. In their study conducted in 2017, they found a high prevalence of syphilis acquired in drug users in the state of Pará, even higher than that presented in individuals involved in prostitution. This reinforces the present study since the Metropolitan region tends to have easier access to illicit drugs than less urbanized regions.

Moreover, it can be inferred that the higher prevalence in the Lower Amazon is associated with a lack of information since the locations that are not part of the metropolitan region tend to be more neglected than those closer to the capital. It is a phenomenon that was reported by Silva et al.17 as framing a profile of vulnerability, characterized by care gaps.However, neglected mesoregions such as the Northeast and Southeast of Pará, as much as they are as populous as the Metropolitan, showed a considerably lower prevalence. The failure in the healthcare network is even greater in these regions, increasing underreporting.

Therefore, health surveillance needs to be constant, and more efficient public policies need to be employed in primary care to reduce the number of cases and make early diagnoses with appropriate treatment. Improving knowledge about the epidemiological data on syphilis is essential to guide health professionals toward an earlier diagnosis and serve as a basis for intervention strategies to prevent the disease.

Conclusion

This study corroborates the reports on new syphilis burden recently. Five thousand six hundred twenty cases of acquired syphilis were recorded in the state of Pará. The study results showed that this form of the disease is still quite prevalent in the Amazon region, especially in the state of Pará, which is marked as a public health problem that requires intervention.It was still found in more significant numbers in the lower socioeconomic levels and, mainly, in young adults, males, reaching mostly the metropolitan mesoregion of Belém.

Additional information

Conflicts of interest: No conflicts of interest declared concerning the publication of this article.

Indications about the contributions of each author:

Conception and design of the study: CAAP

Analysis and interpretation of data: BSAN, MBA, CAAP

Data collection: BSAN, MBA, CAAP

Writing of the manuscript: BSAN, MBA, CAAP

Critical revision of the article: BSAN, MBA, CAAP

Final approval of the manuscript*: BSAN, MBA, CAAP

Statistical analysis: CAAP

Overall responsibility: CAAP

*All authors have read and approved of the final version of the article submitted to Rev Cienc Saude.

Funding information: Not applicable