Introduction

Monkeypox is a rare viral zoonosis, which is caused by monkeypox virus (MPXV) (Figure 1) of orthopoxvirus genus, including smallpox virus, the pathogen of smallpox. The incubation period of monkeypox is usually 6~13 days, but it may also be 5~21 days. Monkeypox patients usually begin with fever, myalgia, fatigue and headache, and then usually develop maculopapules at the primary infection site, which can spread to other parts of the body (Di Giulio and Eckburg, 2004). Monkeypox virus can be transmitted between animals and humans, and can also be transmitted twice between humans (Sklenovska and Van Ranst, 2018).

The first monkeypox case was confirmed in Congo (DRC) in 1970 (Ladnyj et al., 1972). Historically, monkeypox outbreaks mainly occurred in Central and West African countries. There were relatively few monkeypox outbreaks in countries outside Africa, which were all imported from African countries (animals or people), with limited local transmission. However, monkeypox in 2022 brings worrisome challenges to the world. Since May 2022, monkeypox has continued to spread for the first time in Europe, America and other non endemic countries and regions. As of September 14, a total of 59 147 confirmed cases of monkeypox have been reported in 103 countries and regions around the world.

Monkeypox patients are infectious when symptoms appear (usually lasting for 2~4 weeks). Close physical contact with people with symptoms may lead to monkeypox infection. Rashes, body fluids (such as fluid from skin damage, pus, or blood), and dry scabs are particularly infectious. In most cases, patients will recover from monkeypox by self-healing. However, according to the degree of virus exposure, the patients’ health status and the severity of complications, severe patients may also die. At present, there are two evolutionary branches of monkeypox virus, West Africa branch and Congo basin branch, of which Congo basin branch is more infectious, and the fatality rate can reach 10.6%. The sequencing analysis of monkeypox epidemic since May 2022 showed that the virus belongs to the West African branch, and its fatality rate is about 3.6%.

Case Report

On September 16, 2022, a monkeypox case was confirmed in Chongqing Municipality of China, which is the first monkeypox case found in the mainland of China since the global monkeypox epidemic began.

It was reported that the monkeypox patient was a 29-year-old Chinese salesperson who visited Germany from September 2 to 8, had sex with men (MSM) in Berlin on September 2, then went to Spain, and returned to Chongqing Municipality on September 14. He had a dry and itchy throat before, and had a fever, a red rash and pustule on the right thigh on September 9 (Figure 2 A). On September 11, he went to a private clinic and took anti-inflammatory drugs. On September 14, he returned to Chongqing Municipality and was isolated at the isolation point. He said that he had monkeypox-like clinical manifestations. Later, Chongqing Municipal Center for Disease Control and Prevention (Chongqing CDC) determined that he was a suspected case of monkeypox, and collected the clinical samples including blister fluid, nasopharyngeal and oropharyngeal swabs, as well as blood samples.

Based on the primary screening of MPXV based quantitative real-time polymerase chain reaction (qPCR), the samples showed positive results. On September 16, these samples were sent to the National Institute for Viral Disease Control and Prevention (IVDC) of Chinese Center for Disease Control and Prevention, and several qPCR (4-5) and whole genome sequencing (DNBSEQ-G99 by MGI Tech Co., Ltd. China and Oxford/Nanopore) were carried out. QPCR results showed that the monkeypox genome and West Africa strain was detected as positive in the samples. In addition, the swab of blister fluid was directly used for electron microscopy. The results showed that typical mulberry-like particles with a diameter of 150~200 nm were observed, which is the characteristic of MPXV (Figure 2B). Gene sequencing showed that the MPXV strain in this case (China-CQ202209) belonged to B.1 branch of the West African strain, which is highly homologous with the strains from German (GISAID ID: EPI_ISL_13889435) collected on June 21, 2022 (Figure 2C) (China CDC Weekly, 2022).

Discussion

It can be seen from the above case report that the first case of monkeypox in the mainland of China visited Germany, and the MPXV strain in this case (China-CQ202209) is also highly homologous with the strains from German, indicating that the first monkeypox virus in the mainland of China originated from Germany. In fact, since the early May of this year, the epidemic investigation report of monkeypox cases in some non endemic countries and regions has shown that most confirmed cases with travel history have visited Europe and North America, rather than West Africa and Central Africa, where monkeypox is endemic. In this regard, The World Health Organization (WHO) said that it was the first time since the discovery of monkeypox virus that many monkeypox cases were reported simultaneously in both non historically endemic and historically endemic countries and regions of different geographical regions. The China CDC pointed out that the neglected zoonosis monkeypox has now become the focus of the world again, and the alarm of prevention and control in China has sounded.

However, in combination with the transmission mode of monkeypox and the epidemic prevention and control measures in China, it is less likely that monkeypox will spread widely in China. On the one hand, the main hosts of monkeypox virus are rodents and primates, the infected animals and monkeypox infected persons are the main sources of monkeypox infection, the virus generally spread through close contact, and this special mode of transmission limits the transmission range of monkeypox; On the other hand, China’s prevention and control measures against the COVID-19 epidemic can also play a role in preventing the import and spread of monkeypox. The first imported monkeypox case in the mainland of China was just found in the “7+3” isolation process of COVID-19 prevention and control.

A previous study showed that smallpox vaccine has a certain protective effect on monkeypox infection, with the effective rate of 85% and the effectiveness of up to 25 years (McCollum and Damon, 2014). However, since smallpox vaccine may have serious side effects and the spread of monkeypox virus itself is limited, it is not recommended that the whole population be vaccinated against this type of vaccine. Some high-risk population can consider vaccinating the vaccine; while the general population only need to understand the relevant prevention knowledge, maintain good hygiene habits, avoid contact with suspected rodents, primates and monkeypox infected people, and do a good job in self health monitoring.

Conclusions

At present, monkeypox has occurred an unprecedented outbreak around the world, and the first case of monkeypox has also appeared in the mainland of China. According to the current epidemic situation and viral epidemiological characteristics, there may be a certain risk of imported cases in China. However, considering the transmission mode of monkeypox and China’s epidemic prevention and control measures, the risk of monkeypox virus spreading widely in China is low, so there is no need to be too panic. Although smallpox vaccine has a certain protective effect on monkeypox infection, it may have obvious side effects, and the transmission of monkeypox virus itself is limited, so there is no need to vaccinate widely. General population only need to enhance self protection and maintain good health habits.

References

China CDC Weekly, 2022, Notes from the field: the first imported case of monkeypox in the mainland of China - Chongqing Municipality, China, September 16, 2022

Di Giulio D.B., and Eckburg P.B., 2004, Human monkeypox: an emerging zoonosis, The Lancet Infectious Diseases, 4(1):15-25

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Ladnyj I.D., Ziegler P., and Kima E., 1972, A human infection caused by monkeypox virus in Basankusu Territory, Democratic Republic of the Congo, Bulletin of the World Health Organization, 46(5):593-7

McCollum A.M., and Damon I.K., 2014, Human monkeypox, Clin Infect Dis, 58(2):260-7

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Sklenovska N., and Van Ranst M., 2018, Emergence of monkeypox as the most important orthopoxvirus infection in humans, Front Public Health, 6:241

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