A case report published today in JAMA Dermatology highlights concerns about a sexually transmitted fungal infection that belongs to a family of skin infections that are emerging in the United States.

The report describes a New York man in his 30s who developed tinea (ringworm) on his groin, genitalia, arms, and legs following travel in Europe (England and Greece) and California. The man reported multiple male sex partners while traveling, none of whom had similar manifestations, and visited a sauna before developing lesions. After a skin biopsy demonstrated dermatophytosis, the man was treated with the antifungal fluconazole weekly for 4 weeks with no response.

Sequencing of fungal samples from the lesions revealed the infection was caused by Trichophyton mentagrophytes type VII (TMVII), a sexually transmitted fungus that's been reported in patients who had contact with commercial sex workers in Southeast Asia and appears to be circulating locally among men who have sex with men in Europe. 

The patient was treated with terbinafine for 6 weeks, with improvement, then transitioned to itraconazole for persistent infection.

Dermatologists should be on alert

"Healthcare providers should be aware that Trichophyton mentagrophytes type VII is the latest in a group of severe skin infections to have now reached the United States," lead study author Avrom Caplan, MD, a dermatologist at New York University Grossman School of Medicine, said in a university press release.

A report published in the same journal in May described 11 tinea cases in New York that were caused byTrichophyton indotinea, linked to travel to Southeast Asia, and resistant to first-line antifungals. 

Healthcare providers should be aware that Trichophyton mentagrophytes type VII is the latest in a group of severe skin infections to have now reached the United States.

Caplan and his co-authors say that while the number of cases is small, dermatologists should be on the alert for signs of TMVII and T indotinea.

"Since patients are often reluctant to discuss genital problems, physicians need to directly ask about rashes around the groin and buttocks, especially for those who are sexually active, have recently traveled abroad, and report itchy areas elsewhere on the body," said senior study author John Zampella, MD.

Primary Zika virus (ZIKV) infection raised the risk of disease caused by the dengue virus (DENV) 3 serotype and DENV4—but not DENV1—in a cohort of Nicaraguan children, a finding that held true for those infected with DENV before ZIKV but not for those infected with ZIKV before DENV, according to a new study in Science Translational Medicine.

Scientists at the Sustainable Sciences Institute in Managua, Nicaragua, and their US colleagues assessed how previous DENV and ZIKV immunity influences the risk of severe dengue among 3,412 participants in 2022, when all four DENV serotypes circulated in the country. The team analyzed longitudinal clinical and serologic data to define infection histories and used models and repeat measurements to predict risk.

"Infection with any of the four dengue virus serotypes (DENV1–4) can protect against or enhance subsequent dengue depending on preexisting antibodies and infecting serotype," the study authors wrote. "Additionally, primary infection with the related flavivirus Zika virus (ZIKV) is associated with increased risk of DENV2 disease."

ZIKV and DENV are orthoflaviviruses, a genus that also includes viruses such as those that cause West Nile disease, tickborne encephalitis, and yellow fever.

Consideration of cross-reactivity in testing vaccines

Of the 3,412 children, 10.6% contracted dengue caused by the DENV1 serotype (139 patients), DENV4 (133), DENV3 (54), DENV2 (9), or an undetermined serotype (39).

We thus find that prior ZIKV infection, like prior DENV infection, is associated with increased risk of disease with certain DENV serotypes.

Compared with no previous infection with an orthoflavirus, primary ZIKV infection was tied to an increased risk of DENV4 (relative risk [RR], 2.62) and DENV3 (RR, 2.90) disease but not DENV1. Primary DENV infection or DENV followed by ZIKV infection was also linked to an elevated risk of DENV4 infection.

By reanalyzing 19 years of cohort data, the team showed that previous orthoflavivirus immunity and antibody concentration had distinct ties to infection risk, depending on infecting serotype. "We thus find that prior ZIKV infection, like prior DENV infection, is associated with increased risk of disease with certain DENV serotypes," the researchers concluded. "Cross-reactivity among flaviviruses should be considered when assessing vaccine safety and efficacy."