Trichophyton indotineae, a new species of dermatophytes, has become a significant concern in treating dermatophytosis due to the high level of terbinafine resistance reported in this organism. This is the first report of Trichophyton indotineae infection in Central Vietnam. Antifungal susceptibility testing showed that this isolate was susceptible to itraconazole, voriconazole, and terbinafine. Therefore, the patient was successfully treated with oral itraconazole and ketoconazole topical cream.

The prevalence of hepatitis E virus (HEV) in the Vietnamese population remains underestimated. The aim of the present study was to investigate the seroprevalence of HEV IgG/IgM antibodies and the presence of HEV RNA in blood donors as a part of epidemiological surveillance for transfusion-transmitted viruses. Serum samples from blood donors (n = 553) were analysed for markers of past (anti-HEV IgG) and recent/ongoing (anti-HEV IgM) HEV infections. In addition, all serum samples were subsequently tested for HEV RNA positivity. The overall prevalence of anti-HEV IgG was 26.8% (n = 148/553), while the seroprevalence of anti-HEV IgM was 0.5% (n = 3/553). Anti-HEV IgG seroprevalence in male and female donors was similar (27.1% and 25.5%, respectively). A higher risk of hepatitis E exposure was observed with increasing age. None of the blood donors were HEV RNA positive, and there was no evidence of HEV viraemia. Although the absence of HEV viraemia in blood donors from Northern Vietnam is encouraging, further epidemiological surveillance in other geographical regions is warranted to rule out transfusion-transmitted HEV.

The Trichophyton mentagrophytes complex comprises a group of dermatophytes fungi responsible for various dermatological infections. The increasing drugs resistance of this species complex, especially terbinafine-resistance of Trichophyton indotineae, is a major concern in dermatologist practice. This study provides a comprehensive analysis of T. mentagrophytes complex strains isolated from patients in Hue City - Vietnam, focusing on their phenotypic and genetic characteristics, antifungal susceptibility profiles and molecular epidemiology. Keratinophilic fungi from dermatophytosis culture samples were identified morphologically and phenotypically, with species and genotypes confirmed by ITS sequencing and phylogenetic analysis. Antifungal susceptibility testing was carried out to evaluate their susceptibility to itraconazole, voriconazole and terbinafine. The 24% (n=27/114) of superficial mycoses were phenotypically attributed to T. mentagrophytes complex isolates. T. interdigitale, mainly genotype II*, was predominant (44.4%), followed by T. mentagrophytes genotype III* (22.2%), T. indotineae (14.8%), T. tonsurans (11.2%), and T. mentagrophytes (7.4%). While all isolates were susceptible to itraconazole and voriconazole, half of T. indotineae isolates exhibited resistance to terbinafine, linked to the Phe397Leu mutation in the SQLE protein. This study highlighted the presence of terbinafine-resistant T. indotineae isolates in Vietnam, emphasizing the need to investigate dermatophytes drug resistance and implement effective measures in clinical practice. Species diversity within the Trichophyton mentagrophytes complex isolated from dermatophytosis in Hue City, Vietnam, was observed. Terbinafine-resistant Trichophyton indotineae isolates were detected for the first time in Vietnam, emphasizing the importance of implementing antifungal susceptibility testing to effectively manage and prevent the spread of resistant isolates.

Trichomoniasis, the most common non-viral sexually transmitted infection worldwide, is caused by the protozoon Trichomonas vaginalis. The 5- nitroimidazole drugs, of which metronidazole is the most prescribed, are the only effective drugs to treat trichomoniasis. Resistance against metronidazole is increasingly reported among T. vaginalis isolates. T. vaginalis can establish an endosymbiosis with two Mycoplasma species, Mycoplasma hominis and Candidatus Mycoplasma girerdii, whose presence has been demonstrated to influence several aspects of the protozoan pathobiology. The role of M. hominis in T. vaginalis resistance to metronidazole is controversial, while the influence of Ca. M. girerdii has never been investigated. In this work, we investigate the possible correlation between the presence of Ca. M. girerdii and/or M. hominis and the in vitro drug susceptibility in a large group of T. vaginalis isolated in Italy and in Vietnam. We also evaluated, via RNA-seq analysis, the expression of protozoan genes involved in metronidazole resistance in a set of syngenic T. vaginalis strains, differing only for the presence/absence of the two Mycoplasmas. Our results show that the presence of M. hominis significantly increases the sensitivity to metronidazole in T. vaginalis and affects gene expression. On the contrary, the symbiosis with Candidatus Mycoplasma girerdii seems to have no effect on metronidazole resistance in T. vaginalis.

In Vietnam, a rapid decline of P. falciparum malaria cases has been documented in the past years, the number of Plasmodium falciparum malaria cases has rapidly decreased passing from 19.638 in 2012 to 4.073 cases in 2016. Concomitantly, the spread of artemisinin resistance markers is raising concern on the future efficacy of the ACTs. An evaluation of the clinical impact of the artemisinin resistance markers is therefore of interest. The clinical effectiveness of dihydroartemisinin-piperaquine therapy (DHA-PPQ) has been evaluated in three districts characterized by different rates of ART resistance markers: K13(C580Y) mutation and delayed parasite clearance on day 3 (DPC3). Patients were stratified in 3 groups a) no markers, b) one marker (suspected resistance), c) co-presence of both markers (confirmed resistance). In the studied areas, the clinical effectiveness of DHA-PPQ has been estimated as malaria recrudescence within 60 days. The rate of K13(C580Y) ranged from 75.8% in Krong Pa to 1.2% in Huong Hoa district. DPC3 prevalence was higher in Krong Pa than in Huong Hoa (86.2% vs 39.3%). In the two districts, the prevalence of confirmed resistance was found in 69.0% and 1.2% of patients, respectively. In Thuan Bac district, we found intermediate prevalence of confirmed resistance. Treatment failure was not evidenced in any district. PPQ resistance was not evidenced. Confirmed resistance was associated to the persistence of parasites on day 28 and to 3.4-fold higher parasite density at diagnosis. The effectiveness of malaria control strategies was very high in the studied districts. No treatment failure has been observed in presence of high prevalence of ART resistance and in absence of PPQ resistance. K13(C580Y) was strongly associated to higher parasitemia at admission, on days 3 and 28. Slower parasite clearance was also observed in younger patients.

Taenia saginata is a globally distributed tapeworm responsible for human taeniasis due to the ingestion of raw or undercooked beef. T. saginata is present in several Asian countries, including China, Thailand, Lao PDR, Cambodia, and Vietnam, but little is known about its genetic variation. Studying the tapeworm’s phylogeographic patterns is crucial to better understanding their association with the geographic distribution of taeniasis/cysticercosis in human populations. In the present study, 38 specimens of this putative species were collected in central regions of Vietnam and analysed using the mitochondrial gene Cytochrome c Oxidase subunit I (COI) as a molecular marker to assess the correct species identification and investigate the level of genetic variation at different geographic scales. Phylogenetic and phylogeographic analyses were carried out on a dataset that included COI sequences from Vietnamese specimens and from all conspecifics available in GenBank to date. The results showed that the collected Vietnamese specimens belonged to the species T. saginata. In Southeast Asia, signs of a possible founder effect were discovered, with the most common haplotypes frequent and present in many countries, except Lao PDR, which shares its most common haplotype only with individuals from Thailand. Remarkably, a unique taxonomic entity was found worldwide, even though the available COI sequences of T. saginata belonging to non-Asiatic countries are, at present, limited. Therefore, future studies including more COI sequences from a higher number of countries and the use of a combined molecular approach with multiple genetic markers would be useful to provide deeper insight into the global genetic variation of this species.