Investigation into the epidemiology, genetic characteristics, and clinical manifestations of the first monkeypox outbreak in Shenzhen, China

Highlights

• •Scientific question A trend that has emerged in monkeypox outbreaks since 2022 has been a marked change in the transmission pattern of the monkeypox virus (MPXV). This paper comprehensively analyzes the first-ever monkeypox outbreak in Shenzhen, China, including clinical symptomatology, therapeutic approaches, epidemiologic investigation, and comprehensive laboratory testing.
• •Evidence before this study The 2022 outbreak was primarily associated with close intimate contact (including sexual activity), and most cases were diagnosed in men who have sex with men, who often present with novel epidemiologic and clinical features. However, there is no published research related to the local monkeypox outbreak in mainland China.
• •New findings As the first local outbreak of monkeypox, it was suspected that it had been spreading stealthily in Shenzhen for some time. All cases exhibited mild and atypical fever and rash, and were primarily facilitated through close contact and homosexual behavior. MPXV was detected in nasopharyngeal/oropharyngeal/anal swabs and blister fluid of these cases, and all of them are highly homologous to strains collected from Japan in 2023.
• •Significance of the study This paper reports the first local outbreak of monkeypox in Shenzhen City, China, indicating that it is essential to enhance monkeypox surveillance and epidemic information reporting, increase public awareness and training for critical demographic and medical staff, and employ appropriate investigation methods and techniques for epidemiological investigations.

Abstract

This paper comprehensively analyses the first-ever monkeypox outbreak in Shenzhen, China, encompassing clinical symptomatology, therapeutic approaches, epidemiological research, and comprehensive laboratory tests, aiming to establish a robust reference for future monkeypox mitigation and management strategies. The investigation involved a thorough investigation of all identified positive cases, including extensive molecular analysis by nucleic acid detection and whole-genome sequencing of the monkeypox virus. Contact tracing and containment of the infected individuals were also undertaken. Three distinct monkeypox cases were identified in this unique outbreak, exhibiting mild and atypical clinical manifestations, primarily fever and rash. All cases were associated with a single transmission chain, primarily facilitated through close contact and homosexual behavior, indicative of a high-risk factor for monkeypox transmission.

1. Introduction

Monkeypox, a zoonotic disease induced by the monkeypox virus, is known to cause sporadic infections and outbreaks primarily in regions of West and Central Africa. The etiology of the disease dates back to its first identification in the Democratic Republic of the Congo in 1970 [1]. The characteristic symptomatology of the disease entails a febrile condition followed by an extensive rash, which is typically mild and atypical, as observed in the cases presented in this study [2], [3].

However, the epidemiological paradigm of the disease underwent a transformative shift in 2022. The virus spread beyond its endemic territories, pervading various international territories across Europe and North America [4], [5]. This significant geographical spread and subsequent international affliction impelled the World Health Organization (WHO) to declare monkeypox as a Public Health Emergency of International Concern in July 2022 [6].

Despite collaborative international efforts to curb the disease's spread, the virus continued to spread across different geographical regions. By June 2023, monkeypox had infiltrated 111 countries or regions globally [2]. In addition to Europe and North America, several countries in Asia reported new monkeypox cases, including various cities or regions in China, such as Taiwan, Hong Kong, Chongqing, Beijing, Guangzhou, and, more recently, Shenzhen [7], [8], [9].

Notably, a trend that emerged in these recent outbreaks since 2022 was a marked change in the transmission pattern of the monkeypox virus. The disease was primarily transmitted through close contact, which included intimate physical or sexual activities [10]. Most of these reported cases were associated with men who have sex with sex with men (MSM), indicating a crucial epidemiological factor that could play a significant role in the disease's transmission dynamics and potentially aid its prevention and control [2]. This trend prompted a comprehensive investigation when the first monkeypox outbreak was reported in the city of Shenzhen on June 9, 2023. In this paper, we described, in detail, the clinical manifestations, medical treatments administered, epidemiological investigations conducted, and the results of laboratory tests undertaken for the Shenzhen monkeypox outbreak. We aim to provide valuable reference material to enhance our understanding and improve prevention and control strategies for future monkeypox outbreaks.

2. Materials and methods

2.1. Index case

At precisely 22:00 on June 8, 2023, the Shenzhen Center for Disease Control and Prevention (CDC) was notified by the Futian District CDC of an atypical dermatological presentation in a male patient who had recently undergone an anal surgical procedure within their precinct. The patient manifested cutaneous eruptions predominantly on the face, extremities, and torso. The preliminary medical hypothesis pointed towards monkeypox due to his recent sexual engagement with male partners. In an immediate response to determine the potential of a monkeypox outbreak, authenticate the pathogenic identity, and prevent further disease dissemination, the Shenzhen CDC deployed its personnel to conduct an urgent epidemiological investigation on the same day.

2.2. Subjects and analytical techniques

Case-based epidemiological investigations were conducted to determine to teach patients travel history, chronology of symptom onset, medical interventions received, exposure history to high-risk behaviors, and the identities of individuals who had been in close contact. Information regarding clinical presentations, previous infection records, and disease progression was obtained through comprehensive consultation with each patient's medical team and a thorough review of pertinent medical records.

2.3. Laboratory testing

Patients were tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen during their fever spell. Numerous specimens were collected for the molecular detection of the monkeypox virus and viral sequencing. These specimens included nasopharyngeal swabs, oropharyngeal swabs, vesicular fluid, blood (anticoagulant and non-anticoagulant), anal swabs, and urine samples. The protocols of specimen collection, storage, and transportation were adhered to as per the guidelines outlined in the Technical Guidelines for Prevention and Control of Monkeypox (2022 edition) [11].

2.3.1. Monkeypox virus nucleic acid detection

The initial procedure involved the extraction and purification of nucleic acids utilizing a dedicated nucleic acid extraction or purification kit (qEx-DNA/RNA virus, Tianlong Technology, Xi'an, China) and a nucleic acid extractor (Tianlong GeneRotex96, Tianlong Technology, Xi'an, China). Approximately 200 µL of thoroughly mixed sample solution, inclusive of serum, rash material, scab, vesicular fluid, and oropharyngeal or nasopharyngeal secretions from the suspected patients, was utilized for this process.

Subsequently, the extracted nucleic acid samples underwent a fluorescent PCR assay facilitated by a Monkeypox Virus Nucleic Acid Detection Kit (YJC70115N, Jiangsu Bioperfectus Technologies, China) and a fluorescent PCR detector (Hongshi SLAN-96P/S, China). A plasmid encompassing the sequence of the detection site served as the positive control. The primers and probes used to detect the monkeypox virus are shown in the following Table 1 [12].

Table 1.

Primers and probes for monkeypox virus assays [12].

Sequence name	Concentration	Sequence (5′→3′)
F3L-F	10 μM	5′-CTCATTGATTTTTCGCGGGATA-3′
F3L-R	10 μM	5′-GACGATACTCCTCCTCGTTGGT-3′
F3L-P	10 μM	5′FAM-CATCAGAATCTGTAGGCCGT-MGB 3′

The polymerase chain reaction (PCR) conditions were: one pre-denaturation cycle at 95°C for 5 min; denaturation at 95°C for 10 s; and annealing, extension, and fluorescence detection at 58°C for 30 s for 45 cycles.

2.3.2. Monkeypox virus genome enrichment and sequencing library construction

The construction of the Monkeypox Virus Genome Enrichment and Sequencing Library involved primer design against the monkeypox reference genome (NC_063383.1) utilizing the ATOPlex platform (https://atoplex.mgi-tech.com/). According to the manufacturer's instructions, ten microliters of the extracted DNA underwent whole-genome amplification using the ATOPlex Multiplex PCR Amplification kit (MGI, China),

PCR cycling parameters included an initial denaturation step at 37°C for 5 min, followed by 95°C for 5 min, 37 cycles of 95°C for 20 s, 60°C for 1 min, and 58°C for 1 min, and a final extension step at 72°C for 20 s, with a final extension step at 72°C for 1 min. The resulting PCR product underwent purification using MGI Clean Beads (MGI, China) and was subsequently processed into a library using the MGIEasy Fast PCR-Free FS DNA Library Prep Kit (MGI, Shenzhen, China), according to the manufacturer's instructions.

Libraries were then quantified using a Qubit 4.0 instrument (Invitrogen, USA) and normalized. The DNBSEQ OneStep DNB facilitated the subsequent circularization of the normalized libraries Make Reagent Kit (MGI, China), creating DNA nanoballs (DNBs). The DNB libraries were sequenced on a DNBSEQ-G99 sequencer with SE100+10+10, according to the manufacturer's standard protocol.

2.4. Data processing and variant detection

The MGI MPXV software package (MGI, China) was used to analyze the sequencing data to identify mutation sites, consensus sequences, and monkeypox virus lineage. The systematic process involved removing raw sequencing reads containing adapters and low-quality scores. High-quality sequencing reads were aligned against the monkeypox reference genome (NC_063383.1) using the bwa mem algorithm with default options [13]. Precise variant detection necessitated the removal of primers to prevent any potential interference. Variant detection was subsequently conducted using Freebayes software [14], retaining only mutation sites with a frequency greater than 40%. The assembled consensus sequence was derived, enabling lineage determination of the monkeypox virus.

2.5. Phylogenetic analysis

MAFFT v7.520 was used to perform multiple sequence alignment, and IQ-TREE v2.2.2.7 was applied for phylogenetic tree construction using the maximum likelihood method with the following parameters: iqtree -s aligned.fasta -m MFP -nt AUTO -b 1000 –redo [15], [16]. Phylogenetic trees were then visualized using Interactive Tree Of Life (iTOL) v6.7.6(https://itol.embl.de) with the corresponding features of each isolate to determine the possible sources of monkeypox virus transmission in this study. Monkeypox virus genomes were collected from GISAID (https://www.epicov.org/epi3/cfrontend#3a1c72) and were analyzed collectively.

3. Results

3.1. Outbreak description

The outbreak comprised three confirmed cases of monkeypox, all identified in males from different professions residing in the Longgang District, Shenzhen. The index case (Case 1) was identified during his medical treatment, while the subsequent cases (Cases 2 and 3) were discovered during the screening of his close contacts.

3.2. Clinical manifestations and treatment

3.2.1. Case 1

Case 1 had a prior syphilis infection but was human immunodeficiency virus (HIV)-negative. On May 27, 2023, he developed a fever and simultaneously tested positive for SARS-CoV-2 antigen, indicating a secondary infection. Following the cessation of the fever on May 28, a facial rash emerged. On June 2, he visited the dermatology clinic at Hospital A in Shenzhen, where he was found to have multiple erythemas and papules across his body. Diagnosed with “urticaria,” he was prescribed triamcinolone acetonide aconazole cream, ebatin tablets, and compound glycyrrhizin capsules. On June 4, he visited the dermatology clinic at Hospital B in Shenzhen. A physical examination revealed scattered papules, some with pus and scab, on his head and neck. Routine blood tests and C-reactive protein tests yielded typical results, and HIV testing was negative (see Table 2). Diagnosed again with urticaria, he was treated with mupirocin ointment and nometasone ointment.

Table 2.

Blood routine test results of three cases.

Projects	Case 1	Case 2	Case 3	Projects	Case 1	Case 2	Case 3
WBC(109/L)	7.99	8.74	5.46	HCT(%)	41.20	44.30	45.00
NEUT%	62.00	39.00↓	40.00	MCV(fL)	86.00	88.10	86.70
LYMPH%	31.20	45.00	44.70	MCH(pg)	29.40	29.80	29.90
MONO%	6.30	13.30↑*	9.30	MCHC(g/L)	342.00	339.00	344.00
EO%	0.00↓	1.80	5.50	RDW-CV(%)	13.10	11.90	12.90
BASO%	0.50	0.90	0.50	RDW-SD	40.90	38.30↓	40.80
NEUT#(109/L)	4.96	3.41	2.18	PLT(109/L)	341.00	259.00	240.00
LYMPH#(109/L)	2.49	3.93↑	2.44	PDW(%)	10.40	9.90	10.10
MONO#(109/L)	0.50	1.16↑*	0.51	MPV(fL)	9.10	8.50	9.50
EO#(109/L)	0.00↓	0.16	0.30	PCT(%)	0.31↑	0.22	0.23
BASO#(109/L)	0.04	0.08↑	0.03	P-LCR(%)	18.90↓	14.90↓	20.00
RBC(1012/L)	4.79	5.03	5.19	IG%	1.10↑	0.30	0.40
HGB(g/L)	141.00	150.00	155.00	IG#	0.09↑	0.03	0.02

*The number and proportion of monocytes increased in Case 2, and there are no abnormalities in the blood routine results of Case 1 and Case 3. Abbreviations: WBC, white blood cell count; NEUT%, percentage of Neutrophil; LYMPH%, percentage of lymphocytes; MONO%, percentage of monocytes; EO%, percentage of Eosinophils; BASO%, percentage of basophil; NEUT#, neutrophil count; LYMPH#, lymphocytes count; MONO#, monocytes count; EO#, eosinophils count; BASO#, basophil count; RBC, red blood cell count; HGB, hemoglobin concentration.

On the same day, Case 1 was admitted to Hospital C, an anorectal specialist hospital, due to recurrent anal pain during and after defecation over the past week. He was diagnosed with an anal fissure and mixed hemorrhoids. Following standard procedures, an electrocardiogram, chest X-ray, and abdominal color Doppler ultrasound were performed. On June 5, surgery was conducted for anal fissure resection and external stripping and internal ligation of mixed hemorrhoids, after which he remained in the hospital for recovery. On June 8, Case 1 self-discharged from Hospital C and visited the dermatology outpatient department at Hospital D in Shenzhen. His physical examination revealed red or dark red, soybean- to pea-sized, wheal-like papules on the face and limbs, some of which had central crusts and a few scratches. Diagnosed with papular urticaria, he was prescribed desloratadine citrate disodium tablets, epinastine capsules, fluticasone propionate cream, and mupirocin ointment. Following this, Case 1 returned to Hospital C for continued hospitalization. On the same day, Case 1 disclosed his recent sexual activities with men to the medical staff at Hospital C. Given his clinical symptoms and signs, along with this revelation, he was considered a suspected case of monkeypox.

3.2.2. Case 2

Case 2 was free from syphilis and HIV infection. He was categorized as a close contact due to his sexual contact with Case 1 on May 27, 2023. The next day, May 28, the patient tested positive for SARS-CoV-2 antigen, indicating a secondary infection, and remained home-bound until May 30. On June 4, he developed a mild fever (peaking at 37.5°C), which he temporarily managed with ibuprofen. On June 5, he visited a nearby clinic, where his body temperature was recorded as 39.5°C. Suspecting influenza, the physician administered an intramuscular antipyretic injection and oral ceftazidime, relieving the fever. On June 7 and 8, he developed rashes on his abdomen, head, and face. On June 9, a rash appeared on his left inner arm, and the facial rash evolved into herpes.

3.2.3. Case 3

Case 3 tested negative for syphilis and HIV. He was considered a close contact as he shared living quarters with Case 2. On June 1, the patient developed symptoms of fever (reaching 38°C), runny nose, and dry throat. He tested positive for SARS-CoV-2 antigen on the same day (indicating a secondary infection) and self-administered anti-influenza granules and ibuprofen. While he continued to have a low-grade fever on June 8, it subsided by June 9, the same day two red rashes were noticed on his chest.

3.3. Epidemiological investigation and control measures

All three cases were unmarried men aged 25, 27, and 26, respectively. While Case 1 lived with his family, Cases 2 and 3 were housemates. All three were residents of Shenzhen since May 2023, with no history of international travel or interactions with overseas individuals or animals. On May 27, 2023, Cases 1 and 2 confirmed having sex with each other at Case 2's residence. Case 2 was the insertive partner and used protection during the encounter. Both denied any other sexual involvements. Case 2 and Case 3 had shared living arrangements for 5–6 years, sleeping in the same bed but using separate personal items. Case 3 denied being homosexual, having sexual relations with Case 2, or knowing Case 1.

Based on the epidemiological history, diagnosis, and treatment, the Department of Disease Control and Prevention carried out contact investigation and management at the residences of the cases and the medical facilities where they received treatment, following the “Guidelines for the Identification and Management of Monkeypox Contacts” (Table 3).

Table 3.

Contacts identification and testing results. The numbers in this table indicate the number of people that contact with the cases in specific ways.

Case	Type of contact	Close contacts	Testing results of close contacts	General contacts	Testing results of general contacts
Case 1	Live together	3	Negative	0	–
	Diagnosis and treatment	11	Negative	68	Negative
	Homosexual behavior	1	Positive	0	–
Case 2	Live together and share a bed	1	Negative	0	–
	Diagnosis and treatment	0	–	1	Negative
Case 3	–	–	–	–	–

3.4. Real-time quantitative fluorescence PCR and SARS-CoV-2 antigen test results

The Real-time quantitative fluorescence PCR results (Ct value) are shown in Table 4. As shown in Table 4, all the nasopharyngeal and herpes swabs were positive for MPV in these three cases. Two of three cases were positive in the oropharyngeal and anal swabs. However, all the urine samples from them were negative.

Table 4.

The real-time quantitative fluorescence polymerase chain reaction (PCR) for the monkeypox virus (MPXV) (Ct value) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen test results.

Sample	Case 1	Case 2	Case 3
Nasopharyngeal swab	35	35	37
Oropharyngeal swab	Negative	29	31
Blister fluid	31	27	34
Anal swab	28	34	Negative
Urine	Negative	Negative	Negative
Nasopharyngeal swab (SARS-CoV-2 antigen test)	Positive	Positive	Positive

Each patient tested positive for SARS-CoV-2 antigen during their fever spell, indicating a secondary infection, so it was impossible to rule out that the related symptoms resulted from SARS-CoV-2 infection.

3.5. Monkeypox virus sequencing results

The phylogenetic tree based on the maximum likelihood approach of the different monkeypox virus (MPXV) lineages collected from GISAID and 3 MPXV sequences analyzed in this study were shown in Fig. 1. The phylogenetic tree of the 3 MPXV discovered from Shenzhen, China, and 45 MPXV sequences (samples were collected from January 1, 2023, to July 3, 2023) downloaded from GISAID were shown in Fig. 2. Nextclade analysis (https://clades.nextstrain.org/) revealed post-genome sequencing that all three cases in Shenzhen were infected with the human monkeypox virus (hMpxV, B.1. 3 evolutionary branch).

Fig. 1.

The phylogenetic tree based on the maximum likelihood approach of the monkeypox virus (MPXV) with different lineages.

Fig. 2.

The phylogenetic tree of the 3 the monkeypox virus (MPXV) discovered from Shenzhen, China, and 45 MPXV (samples were collected from January 1, 2023, to July 3, 2023) were downloaded from GISAID.

To further explore the correlation with the genomes of other worldwide monkeypox cases, we downloaded the genome sequences of 71 monkeypox cases sampled and sequenced since 2023 from GISAID. We subsequently generated an evolutionary tree with six domestic cases (3 from Shenzhen, 2 from Chongqing, and 1 from Hangzhou) based on SNPs in the core genome using the maximum likelihood approach and refined the tree using iTOL. As per the evolutionary tree, the Shenzhen cases, along with the cases in Hangzhou case, belong to the same minor evolutionary branch and show high homology. China-SZ-2023-06-case3 in Shenzhen is a new variant genome produced by ongoing evolution and mutation from the genome of case China-SZ-2023-06-case2, not dismissing the possibility that Cases 1, 2, and 3 belong to the same transmission chain.

Furthermore, phylogenetic tree analysis with all B.1.3 gene sequences globally shows that the four local cases in Shenzhen and Hangzhou are on the same evolutionary branch as many recent Japanese monkeypox cases. From an evolutionary perspective, these four Chinese cases are highly homologous to strains from Japan collected in January, February, and March 2023 (GISAID ID: EPI_ISL_17445514, EPI ISL 17445515, EPI ISL 17692269).

4. Discussion

In this outbreak, patients exhibited low to moderate fever and rashes on the head, face, body, and limbs. The onset of illness began with fever in all three cases, accompanied by mild discomfort, fatigue, headache, and other symptoms. The rashes appeared 1–2 days after the fever subsided and affected the head, face, trunk, and limbs without any discernible pattern. Case 1 and Case 2 presented with early symptoms and rashes, and physical examination revealed the rash's progression from macules to papules, herpes, and pustules. In Case 1, some pustules had crusted, and different forms of the rash could coexist. In general, the clinical manifestations of all cases in this outbreak were relatively mild and non-standard, consistent with international reports[17], [18].

Based on the findings from the epidemiological investigation and full viral genome sequencing, it appears likely that Case 2 infected Case 1 through homosexual contact and later infected Case 3 via close contact. The index patient in this outbreak, Case 1, exhibited onset of illness and rash around May 27, 6–7 days before Case 2's symptoms surfaced. It is inferred that they engaged in homosexual interactions at least once prior to May 27, and it most likely occurred before an average incubation period of 7–10 days [19], [20]. It is suggested that the incubation period of Case 2 may have been longer than that of Case 1. The exposure timeline of all three cases remains unclear, and due to the influence of SARS-CoV-2 infection, the exact timing of symptoms onset is uncertain, making it impossible to accurately determine the incubation period. All three were residents of Shenzhen since May 2023, with no history of international travel or interactions with individuals or animals overseas. As the first outbreak of monkeypox in Shenzhen, it was suspected that it had been spreading stealthily in Shenzhen for some time.

The contact tracing investigation of this monkeypox outbreak identified two positive cases attributed to homosexual behavior and close contact (sharing a bed). No additional secondary positive cases were found among close contacts, such as family members sleeping in separate beds, medical staff performing operations, and other general contacts. This suggests that close interactions such as homosexual behavior and bed-sharing present high-risk factors for monkeypox transmission [10], [18].

The above-said findings and containment process of this outbreak revealed deficiencies in the current surveillance, prevention, and control measures for monkeypox. First, medical institutions demonstrate insufficient surveillance sensitivity. Since 2022, identified monkeypox cases have presented relatively mild and non-standard clinical manifestations, making it challenging for physicians to diagnose monkeypox based solely on general febrile symptoms or non-standard rash manifestations [2], [3]. Due to inadequate training and publicity concerning monkeypox, physicians failed to obtain epidemiological information about monkeypox from patients, and patients lacked the knowledge to proactively inform physicians about potential risks. Second, the epidemiological investigation methods for monkeypox cases are limited. Since 2022, monkeypox epidemics have predominantly affected MSM, who are characterized by their discreet nature and mobility [2], [10]. Due to MSM's desire to protect their privacy, traditional epidemiological investigation methods struggle to confirm exposure, symptom onset time, and contacts, negatively impacting the prevention and control of the epidemic.

On May 11, 2023, WHO declared that the monkeypox epidemic no longer constituted a Public Health Emergency of International Concern. However, this does not signify the end of relevant prevention and control efforts, and countries must continue to implement robust and sustainable response measures. With the gradual resumption of international flights, port cities like Shenzhen face an increasing risk of monkeypox outbreaks, especially among MSM. Given the contagious nature of the disease and the intricacies involved in its prevention and control, this outbreak underlines the need for more stringent measures in managing and curtailing the spread of the disease. This requirement to strengthen monkeypox surveillance and information reporting and to reinforce public awareness is one of the key conclusions of this analysis [11].

The research and observations from this outbreak underlie the critical role of surveillance and epidemic information reporting in managing and controlling future outbreaks. Without effective surveillance, authorities cannot detect initial cases promptly, allowing the disease to spread unchecked. Given the global movement of people, a major focus should be placed on strengthening surveillance systems in Shenzhen and other parts of the world. The outbreak has underscored the value of a robust and comprehensive information reporting system, helping to provide real-time updates and aiding authorities in making swift, informed decisions.

Additionally, the importance of public awareness cannot be overstressed. In the event of an outbreak, a well-informed public can play a pivotal role in controlling and reducing the spread of the disease. Therefore, the authorities should focus on public health education campaigns to raise awareness about the signs, symptoms, and prevention of monkeypox. Targeted efforts towards at-risk populations, such as MSM and the acquired immunodeficiency syndrome (AIDS) population, are particularly crucial given their higher exposure risk [21]. The capacity to identify symptoms early may allow for more rapid treatment and reduce the likelihood of onward transmission.

Moreover, the monkeypox outbreak underlines the need for more intensive training of healthcare personnel. The difficulty in diagnosing monkeypox based on symptoms alone, as evidenced by this recent outbreak, underscores this need. The absence of characteristic symptoms and the resemblance to other diseases, such as SARS-CoV-2, make it vital for healthcare professionals to be adequately trained in the recognition and management of monkeypox [21]. This training should include symptom recognition, understanding of the epidemiological information associated with monkeypox, and the proper procedures for dealing with suspected cases.

Finally, the analysis of this outbreak also emphasizes the importance of employing suitable investigative methods and techniques in epidemiological investigations. The discreet nature and mobility of groups such as MSM make traditional investigation methods inadequate. Thus, innovative techniques and approaches need to be developed better to track exposure, symptom onset time, and contacts. Involvement of professional staff experienced in the investigation and counseling of MSM can also provide valuable insights into their behaviors and patterns, aiding in the control and prevention of future outbreaks.

5. Conclusions

This paper describes the first outbreak of monkeypox in Shenzhen, China. It is imperative to enhance monkeypox surveillance and epidemic information reporting, increase public awareness and training for critical demographic and medical staff, and employ appropriate investigation methods and techniques for epidemiological investigations.

Ethics statement

The Ethics Review Committee of the Shenzhen Center for Disease Control and Prevention (Approval number: QS2023060051) approved the study. Written informed consent was obtained from the study participants.

Acknowledgements

This study was supported by the Science and Technology Planning Project of Guangdong Province of China (Grant 2021 B1212030009), Sanming Project of Medicine in Shenzhen (No. SZSM202011008), Research Foundation of Shenzhen Science and Technology Emergency Key Technology Program (JSGG20220301090007009), and Shenzhen Key Medical Discipline Construction Fund (SZXK064).

Conflict of interest statement

The authors declare that there are no conflicts of interest.

Author contributions

Jia Wan: Conceptualization, Writing – original draft, Investigation, Formal analysis. Xiaomin Zhang: Investigation, Formal analysis. Jing Qu: Investigation, Formal analysis. Bo Peng: Investigation, Formal analysis. Dongfeng Kong: Investigation, Formal analysis. Jianhua Lu: Supervision, Writing – review & editing. Qinghua Hu: Supervision, Writing – review & editing. Zhifeng Zhou: Investigation, Formal analysis. Haiduan Lin: Investigation, Formal analysis. Xiangjie Yao, Yulin Fu: Investigation, Formal analysis. Qing Xu: Investigation, Formal analysis. Ying Lin, Yan Yang, Jinzhen Tang, Lin Lin, Huimin Li: Investigation, Formal analysis. Ziquan Lv: Investigation, Formal analysis. Zhen Zhang: Investigation, Formal analysis. Xuan Zou: Supervision, Writing – review & editing. Xiaolu Shi: Conceptualization, Writing – original draft, Writing – review & editing, Investigation, Formal analysis.