Most monkeypox cases in Guangdong province have been linked to male-to-male sexual contact, according to a study by Chinese medical researchers.

The research was published online late last month in the journal Nature Communications by a team from the Third People's Hospital of Shenzhen and the Shenzhen National Clinical Research Center for Infectious Diseases.

The study examined 92 monkeypox cases, all of whom were male with a median age of 30. Researchers found that 95.7 percent had a history of male-to-male sexual contact. Additionally, 56.5 percent of the patients were co-infected with HIV.

The majority of the patients exhibited skin lesions in multiple areas, with 62.2 percent having genital lesions, indicating a higher risk of transmission through sexual contact. The study accounted for 30 percent of reported monkeypox cases in Guangdong province and 66 percent of cases in Shenzhen, Guangdong.

The research also explored the evolutionary trajectory and characteristics of the Clade IIb strain of the monkeypox virus, identifying a new lineage, C.1.1, for the first time.

"More than 90 percent of the infected individuals were found to have engaged in male-to-male sexual behavior, highlighting it as a significant risk factor for the spread of monkeypox and similar viruses," said Lu Hongzhou, one of the leading researchers.

Monkeypox was first isolated from a monkey with a fever in 1958. Before 2021, the virus was mainly confined to central and western African countries and was typically associated with direct contact with infected animals. However, since June last year, local transmission of the monkeypox virus has been observed in Shenzhen.

The research team in Shenzhen established a clinical cohort study and used whole-genome amplification sequencing to trace the origins of the circulating monkeypox virus in the city, shedding light on the evolutionary path and features of the Clade IIb strain.

Lu emphasized the challenges of treating monkeypox in HIV-positive individuals, particularly those in advanced stages of AIDS, and stressed the importance of addressing risky behaviors among HIV patients to prevent further infections.

Enhanced health education is needed among male homosexuals to promote safer sexual practices, according to Zhao Wei, director of the biosafety research center at the School of Public Health at Southern Medical University.

"Patients co-infected with HIV and the monkeypox virus, especially those with lower immune function, may have a longer course of illness and are more prone to severe conditions," Zhao said.

China has increased screening measures for incoming travelers at high risk of contracting monkeypox since the World Health Organization declared the outbreak a public health emergency in mid-August, according to the General Administration of Customs.

Travelers arriving from regions affected by monkeypox who have had contact with monkeypox patients or who have experienced symptoms such as fever, headache, back pain, muscle aches, swollen lymph nodes, rash or mucosal lesions are required to report their condition to customs officials upon entry, the administration said.

qiuquanlin@chinadaily.com.cn