Dear Editor,
We read with great interest the study by Gupta et al. on the increasing number of lymphogranuloma venereum (LGV) cases in British Columbia, Canada. The LGV infections were primarily among men who have sex with men (MSM) on HIV pre-exposure prophylaxis (PrEP) and were more likely to be asymptomatic.1 While considered to be rare in high-income countries, LGV cases disproportionately affect MSM and are being observed with increasing frequency among HIV-uninfected men on HIV PrEP.2–4
LGV is considered endemic to parts of Southeast Asia, yet epidemiologic data from the region are sparse. One recent report among MSM in Taiwan, found the prevalence of LGV rectal infections was 1.6%.5 In Vietnam, we have found a high prevalence of rectal C. trachomatis infections among MSM, but the prevalence of LGV is not known.6 Given increasing reports of LGV in other settings, we sought to understand the prevalence of LGV among MSM in an HIV PrEP program in Hanoi, Vietnam.
From January 2022 through May 2023, HIV PrEP program participants in Hanoi who were male, reported having sex with men or transgender women in the prior 12 months were enrolled in a study on the prevalence of C. trachomatis and N. gonorrhoeae infections. Participants self-collected rectal, pharyngeal, and urine samples for testing by nucleic acid amplification testing using either the Roche cobas CT/NG or Abbott m Alinity STI assays. Remnant specimens were stored at −80°C and a subset were selected from available rectal specimens with C. trachomatis to undergo LGV testing. DNA extraction was performed using QiaAmp Mini Kit (Qiagen, Germany), with internal controls. The non-LGV/LGV real-time PCR (RT-PCR) assay was conducted using a 168bp fragment of the pmpH gene for amplification, as described previously.7 The prevalence of rectal C. trachomatis infections in the parent study was 14%. In total, 90 rectal specimens with C. trachomatis infections were selected for LGV testing, with 31% being from participants reporting rectal symptoms in the prior week. All the specimens were negative for LGV by RT-PCR. Internal controls were positive for DNA extraction for all specimens; eight specimens (8.9%) were negative for both LGV and non-LGV, suggesting a low amount of C. trachomatis DNA.
Screening for LGV in rectal C. trachomatis infections among 90 MSM in an HIV PrEP program in Hanoi, Vietnam did not identify any LGV infections. Despite the increasing prevalence of LGV infections among MSM in some settings, there does not appear to be a substantial prevalence in our setting. Recent reports from China and Thailand also did not LGV infections in MSM populations.8,9 The absence of LGV infections in our study might be the result of the relatively limited number of samples tested or reflect the study setting, which was one HIV PrEP program in Hanoi, and might not represent other LGV infections in other settings. Additional research is needed to more comprehensively understand the epidemiology of the LGV infections in the region, particularly among populations living with HIV and on HIV PrEP.
References:
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