Unusual epidemiological presentation of the first reports of monkeypox in a low-income region of Brazil

Monkeypox virus is a zoonotic, double-stranded DNA virus, member of the Orthopoxvirus genus, that occurs primarily in tropical areas of central and west Africa. However, since May 2022, the number of monkeypox cases has increased dramatically worldwide. As of September 14, more than 60,000 cases of the disease had been reported, with Brazil accounting for approximately 10% (https://ourworldindata.org/monkeypox). The first case of monkeypox in Brazil was diagnosed on June 7, 2022, in the state of São Paulo, in a 41-year-old male patient with a recent travel history to Portugal and Spain [1]. Here, we describe the first three cases of monkeypox in Sergipe state, Northeast Brazil, recognized as one of the poorest regions of the country. According to the Brazilian Institute of Geography and Statistics (IBGE, acronym in Portuguese), the state has an estimated population of approximately 2.3 million inhabitants, a Human Development Index of 0.665, and the proportion of illiterates and those living on half the minimum wage per month is 13.5% and approximately 50%, respectively.

All cases were diagnosed between August 22 and August 26, 2022. Samples were obtained from skin lesions and were all positive for monkeypox DNA using real-time polymerase chain reaction (RT-PCR). Dry swabs were incubated in 400 μl of PBS at 37 °C for 30 minutes, with vigorous vortexing every 10 minutes. Total DNA was extracted from the resulting supernatant using a KingFisher Flex System® (Thermofisher, USA) and the MagMax Viral/Pathogen Nucleic Acid Isolation Kit (Thermofisher, USA), according to manufacturer's instructions. Monkeypox DNA was detected using a triplex real-time PCR assay (7500 Thermal Cycler, Applied Biosystems, USA) for Orthopoxvirus targeting the F4L gene, general monkeypox targeting the J2R gene, and the human RNase P gene as endogenous control. Positive samples had cycle threshold (Ct) values less than 37.

The first case involved a 28-year-old woman who sought medical attention 15 days after the onset of systemic symptoms (fever, asthenia, headache, and sore throat) for evaluation of multiple pruritic, papulovesicular lesions on the limbs, trunk, and oral mucosa. The second case was a 12-year-old girl who presented with fever and headache, as well as multiple well-circumscribed pruritic, pustular lesions on the arms, trunk, and face with central umbilication. None of the patients reported any known contact with a confirmed case, people experiencing similar symptoms, or recent travel abroad. The patients were in good clinical condition and did not require hospitalization.

The third case involved a 24-year-old bisexual man who presented to an ambulatory clinic 6 days after the onset of systemic symptoms for evaluation of multiple well-circumscribed pustular lesions on the arms and perianal area with central umbilication. There were no lesions in the oral cavity or genital region. The patient had inguinal lymphadenopathy. Despite his denial of close contact with a confirmed case or travel abroad, the patient reported sexual exposure 10 days before onset of symptoms. Serology tests for HIV and other sexually transmitted infections (STIs) (syphilis and herpes simplex virus) were negative. The patient was in good clinical condition and did not require hospitalization. The clinical and epidemiological characteristics of the patients are detailed in Table 1 .

Table 1.

Clinical and epidemiological characteristics of the first monkeypox cases in the state of Sergipe, Northeast Brazil.

Variables	Case 1	Case 2	Case 3
Sex	Female	Female	Male
Sexual orientation	Heterosexual	Heterosexual	Bisexual
Age	28 years	12 years	24 years
Days between onset of symptoms and onset of lesions	15	1	2
Diagnosis
Method	RT-PCR	RT-PCR	RT-PCR
Sample	Skin swab	Skin swab	Skin swab
Days between the onset of lesions and sampling	1	4	4
Ct values	31	36	16
Systemic symptoms
Lymphadenopathy	No	No	Yes
Inguinal	No	No	Yes
Cervical	No	No	No
Axillary	No	No	No
Fever	Yes	Yes	Yes
Asthenia	Yes	Yes	Yes
Headache	Yes	No	Yes
Myalgia	No	No	Yes
Sore throat	Yes	No	Yes
Mucocutaneous lesions	Yes	Yes	Yes
Location
Hands/feet	No	No	No
Arms/legs	Yes	Yes	Yes
Trunk	Yes	Yes	No
Face	No	Yes	No
Genital	No	No	No
Anal/perianal	No	No	Yes
Oropharynx/oral mucosa/lips	Yes	No	No
Hospitalization	No	No	No
Prior vaccination against smallpox	No	No	No
Known contact with a confirmed case	No	No	No
Travel abroad	No	No	No
Sexual exposure within the 21 days before onset of symptoms	No	No	Yes
Concomitant sexually transmitted infection
Syphilis and herpes simplex virus infection	No	No	No
HIV	No	No	No

Ct, cycle threshold.

Epidemiological studies [2] have shown that most cases of the 2022 monkeypox outbreak have occurred predominantly among men who have sex with (MSM) in their fourth and fifth decades of life, with a high prevalence of lesions in the anogenital region and oral mucosa, suggesting that close skin-to-skin or skin-to-mouth contact during unprotected sexual intercourse is the primary route of monkeypox transmission [3]. In addition to the majority of cases in the current outbreak being associated with high-risk MSM sexual behavior, a high prevalence of HIV and other STIs has been reported among these individuals [4].

Our findings are important because they show an unusual epidemiological presentation of the first reports of monkeypox in the region than has been reported elsewhere. Although one of the three cases was registered in an MSM and the lesions were found in the expected locations, such as the perianal region, the other two cases were recorded in female patients with an unknown transmission route. In particular, one case was diagnosed in a 12-year-old girl without anogenital involvement. Despite most monkeypox cases in endemic areas of Central and West Africa are diagnosed among children and adolescents [5], the prevalence of disease in the pediatric population during the current multi-country outbreak is less than 0.3% [6,7]. Professionals caring for children and adolescents should not base their assessments solely on epidemiological risk factors or exposure to confirmed monkeypox patients. Careful monitoring of upcoming monkeypox cases in the region is required to track the virus spread to the general population. Low-income areas are particularly concerning because poor people have less consistent access to primary care, which can exacerbate virus spread in underserved communities.

Authors contributions

All authors contributed equally to this manuscript.

Financial source

CD thanks CNPq and FAPERJ for research fellowships. These sponsors had no role in the study design, execution, analysis, interpretation of data, or decision to present the results.

Declaration of competing interest

The authors declare they have no conflicts of interest.