Pathogen Pulse: TMVII Outbreak, Travel-Associated Dengue Cases, and More

Trichophyton mentagrophytes type VII Outbreak

Minnesota health officials are warning clinicians and the public about an outbreak of a newly recognized sexually transmitted fungal infection in the Twin Cities metropolitan area.

The infection is caused by Trichophyton mentagrophytes type VII, or TMVII, a fungus that produces ringworm, characterized by round, red, irritated rashes that can appear on the arms, buttocks, trunk, genitals, and legs. “TMVII can cause pruritic, annular, scaly lesions on the trunk, groin, genitals, or face; might be mistaken for eczema, psoriasis, or other dermatologic conditions; and frequently requires oral antifungal therapy,” according to the authors. Unlike traditional ringworm, TMVII has been linked to transmission through skin-to-skin contact, including sexual contact. Fungal spores can also spread via contaminated surfaces.

According to the Minnesota Department of Health, the first confirmed case in the state was identified in July 2025 in a resident who sought care for a genital rash. Since then, officials have documented 13 confirmed cases and 27 suspected cases, all within the Twin Cities area. The outbreak was initially detected after clinicians alerted public health authorities and requested confirmatory testing, prompting the department to establish enhanced surveillance.

TMVII was first reported in the US in 2024 in New York, following earlier reports from Europe, particularly among men who have sex with men. Because the infection is not nationally reportable and can resemble other skin conditions, the true scope of spread remains unclear.

Health officials advise prompt medical evaluation for suspicious rashes. Treatment typically requires extended oral antifungal therapy, and delays may result in prolonged symptoms or scarring.

Travel-Associated Dengue Cases Offer Early Warning for Global Transmission

A new analysis of national surveillance data suggests that dengue cases in US travelers can serve as a reliable early warning system for rising global transmission. “Dengue is a mosquito-borne viral disease of major public health concern, particularly in tropical and subtropical regions. Four dengue virus (DENV) serotypes, transmitted primarily by Aedes spp. mosquitoes, can cause repeat infections; secondary infections might be associated with more severe disease. An estimated 60% to 80% of all DENV infections are asymptomatic or subclinical, complicating surveillance and control,” the authors wrote.

In the study titled “Using Routine Surveillance Data to Assess Dengue Virus Transmission Risk in Travelers Returning to the United States,” researchers examined 10,530 travel-associated dengue cases reported to ArboNET from January 2010 to April 2024, representing travel to 128 countries. By applying negative binomial and Poisson regression models to monthly case counts, the team developed country-specific thresholds at the 75^th, 80^th, and 90^th percentiles to identify periods of elevated risk. They then incorporated a pragmatic case-count rule requiring more than 10 cases within a 3-month window to distinguish sustained transmission from isolated spikes.

“Dengue virus poses a growing global health threat, yet inconsistent local surveillance limits global risk assessments,” the authors wrote. Using traveler data, they were able to detect sustained transmission even in countries with limited public reporting, including Cuba during 2022 to 2023.

Across countries, the median delay between symptom onset and reporting was 1.3 months from 2010 to 2023. Real-time data missed a median of 25% of high-risk months compared with retrospective datasets, highlighting the impact of reporting lags. Threshold selection also influenced alert frequency. At the 75t^h percentile, the median share of months classified as high risk was 33%, compared with 29% at the 80^th percentile and 19% at the 90^th percentile.

Adding the more than 10-case criterion reduced alerts by 52.8%, from 714 to 337, improving specificity while maintaining sensitivity to prolonged outbreaks. For example, Cuba reported 1,609 travel-associated cases and met both criteria in 52 months, “whereas countries such as Singapore, Kenya, and China had both low case counts and few or no alert months.”

The authors conclude that “travel-associated dengue surveillance provides a practical, timely complement to national systems,” particularly when local reporting is incomplete or delayed. While traveler data cannot replace in-country surveillance, integrating both sources may strengthen global monitoring and improve the timeliness of travel health notices.

First Human Case of Streptococcus parasuis Reported in Henan Province, China: Environmental Transmission Suspected

A 69-year-old sanitation worker in Luoyang City has become the first documented human case of Streptococcus parasuis infection in Henan Province, according to a new outbreak report from Chinese public health authorities.

The case was first reported on June 26, 2025, after a hospital initially identified the blood culture isolate as Streptococcus suis using MALDI TOF MS. However, confirmatory testing told a different story. “Average nucleotide identity analysis definitively identified HN04 as Streptococcus parasuis,” investigators reported after whole genome sequencing.

The patient was admitted on June 23, 2025, at 9:00 AM with a crushed left foot injury sustained during work. His temperature was 36.8 °C, and laboratory testing showed a white blood cell count of 8.5×10^9/L with 92.90% neutrophils. A left below-knee amputation lasting 75 minutes was performed the same day. The patient recovered and was discharged on July 14.

Notably, epidemiologic investigation found no livestock exposure. “The patient’s household did not raise pigs or other livestock,” and no pig farms were located near his residence. This finding diverges from the classic occupational pattern seen with S suis infections.

From 2023 to the present, 365 Streptococcus strains have been cultured at the reporting hospital, yet no S suis have been detected. Subsequent testing on June 27 using an S suis nucleic acid kit yielded a negative result, and sequencing completed on August 13 confirmed the isolate as S parasuis, with average nucleotide identity values ranging from 97.69% to 97.85% compared to other human isolates in China.

The authors emphasized that “accurate differentiation from S suis in clinical settings remains challenging,” warning that infections may be underestimated. They recommend strengthening environmental surveillance, expanding diagnostic capacity, and including S parasuis in the differential diagnosis of severe infections even in the absence of livestock contact.

This Pathogen Pulse examines infection prevention worldwide. Minnesota is investigating a TMVII fungal outbreak with 13 confirmed and 27 suspected sexually transmitted cases in the Twin Cities. CDC researchers report 10,530 travel-associated dengue cases from 128 countries between 2010 and 2024 can help detect global outbreaks earlier. In China, the first human Streptococcus parasuis case in Henan was confirmed, with no livestock exposure, raising environmental transmission concerns.