First study on vaginal microorganisms in Madagascar provides new insights into women's health
An international research team led by the Bernhard Nocht Institute for Tropical Medicine (BNITM) has conducted the first comprehensive study of the vaginal microbiota in women of reproductive age in Madagascar. The vaginal microbiota is the community of microorganisms that naturally live in the female genital tract. While vaginal microbiota has been extensively researched in Europe and North America, data from sub-Saharan Africa, especially Madagascar, has been almost completely lacking until now. The researchers also analysed associations between the vaginal microbiota and three common urogenital diseases: infections with the human papillomavirus (HPV), infections with the parasite Schistosoma haematobium, and female genital schistosomiasis, a chronic consequence of this infection. The study was published in the Journal of Infectious Diseases.
The vaginal microbiota plays an important role in women's health. It forms a natural barrier that protects against pathogens. In particular, lactobacilli are considered protective as they produce lactic acid and other antimicrobial substances that inhibit the growth of harmful microorganisms. If these bacteria are absent or the composition of the microbial community changes, the risk of various gynaecological diseases can increase. These diseases include sexually transmitted infections, pregnancy complications or infertility. Researchers distinguish between different typical compositions of the vaginal microbiota, known as community state types (CSTs). Some of these groups are dominated by lactobacilli, while others exhibit a greater diversity of different bacterial species. Most data on vaginal microbiota originates from countries in the Global North. Comparable studies are still lacking in many regions of the world, including Madagascar. At the same time, Madagascar faces a high burden of infections such as the human papillomavirus (HPV) and the parasite Schistosoma haematobium. Both pathogens can affect the genital tract and are associated with various gynaecological diseases.
"Our study provides the first systematic characterisation of the vaginal microbiota in women in Madagascar. This closes a key knowledge gap and broadens the global perspective on vaginal health," explains Dr Jana Hey, first author of the publication and a member of the Implementation Research Group at BNITM.
A different "normal"
For the study, the research team examined 500 women aged 18 to 49 at three health centres in the Marovoay district of Madagascar. The team was able to include 443 participants in the analysis and the results revealed a surprising picture: the majority of the women examined had a highly diverse vaginal microbiota with low lactobacillus dominance. In populations in the Global North, by contrast, lactobacillus-dominated CSTs are common in the vaginal microbiota and are often considered "healthy".
"Our findings challenge the common understanding of what constitutes a 'normal' vaginal microbiota," says study leader Dr Daniela Fusco from BNITM. "A bacterial composition that is considered problematic in Europe may in fact represent a normal state in other parts of the world. This is particularly relevant for global health strategies. It shows that reference values from the Global North cannot simply be applied to other regions."
Microbiota in connection with HPV and genital schistosomiasis
The study also provides new insights into how the vaginal bacterial community is associated with significant infections. In women with HPV infection, the researchers found the bacterial species Dialister significantly more frequently than in HPV-negative subjects. Persistent infection with certain types of HPV can cause cellular changes in the cervix and is considered the leading cause of cervical cancer. The bacterium Dialister has already been linked in other studies to changes in the vaginal environment and tissue alterations in the cervix.
In addition, the research team systematically investigated for the first time the association between the vaginal microbiota and female genital schistosomiasis (FGS). FGS is a chronic condition resulting from infection with the parasite Schistosoma haematobium, which is widespread in Madagascar. In women with FGS, the researchers found increased levels of a bacterial species from the Rhizobiaceae family that has not yet been clearly classified.
"We are still in the early stages here," said Fusco. "Our results suggest that parasitic infections may influence the bacterial composition in the genital tract. Further studies are needed to understand what role these changes may play in gynaecological diseases."
New data as a starting point for further studies
This study provides for the first time valuable insights into the vaginal microbiota of women in Madagascar. At the same time, the results show where further research is needed. As the data were collected at a single point in time, the scientists could not determine whether certain changes in the vaginal microbiota were causes or consequences of infections. In addition, detailed information was not available for all factors that may influence the vaginal microbiota, such as the menstrual cycle, hormonal contraception or other infections. Long-term studies are therefore necessary to analyse the observed associations in more detail. The now-published data form an important basis for such research.
The researchers emphasise that further studies in different regions of the world are also needed to better understand the dynamic relationships between the vaginal microbiota, HPV infections, cervical cancer and parasitic infections.
"Global women's health needs global data," says Hey. "Only by taking into account the diversity of biological and social contexts can we develop fair and effective prevention strategies."
Publikation:
Hey J.C. et al. The Vaginal Microbiota of Adult Malagasy Women of Reproductive Age in the Marovoay District: First Characterization and Exploration of Associations With Human Papillomavirus and Schistosoma haemotobium Infections. Journal of Infectious Diseases 2026, DOI: 10.1093/infdis/jiag065
Contact person
Dr Jana Hey
Research Group Implementation Research
Email : jana.hey@bnitm.de
Dr Daniela Fusco
Group Leader Implementation Research
Phone : +49 40 285380-504
Email : fusco@bnitm.de
Dr Anna Hein
Public Relations
Phone : +49 40 285380-269
Email : presse@bnitm.de
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