A study coordinated by researchers from the Oswaldo Cruz Institute (IOC/Fiocruz) identified, for the first time, the coexistence of the protozoan Giardia lambliaThe study, which causes giardiasis, found opportunistic fungi of different species in the intestines of children, revealing that the disease may be part of a broader imbalance in the gut microbiome.
One of the most common intestinal infections in childhood, giardiasis can cause diarrhea, abdominal pain, gas, nausea, and loss of appetite. In young children, especially those in socially vulnerable settings, the infection can also be associated with weight gain difficulties and developmental impairments.
The research, published in the international scientific journal Frontiers in Cellular and Infection Microbiology, analyzed fecal samples from children attending a daycare center located in a community in the northern part of Rio de Janeiro.
The results revealed a novel association between giardiasis and certain potentially pathogenic yeast species. In total, stool samples from 25 children aged between 1 and 4 years were evaluated. Thirteen tested positive for giardiasis. Giardia lamblia.
Of these, 10 also showed growth of Candida parapsilosis, currently considered an emerging fungus of clinical importance.
In some cases, there was also coexistence with other species, such as Candida tropicalis, Candida krusei e Saccharomyces cerevisiaeCalled 'opportunistic fungi', these microorganisms typically do not cause symptoms when present in the gut microbiota, but tend to multiply excessively if the gut is weakened, whether by inflammation, low immunity, or alterations in internal balance.
According to the researchers, although the study design does not allow for a direct cause-and-effect relationship to be established between the protozoan infection and the presence of fungi, the findings raise an important alert about possible interactions between different microorganisms in the infant gut, especially in contexts of social vulnerability.
"The study reveals the possibility of coexistence, not a cause-and-effect relationship. In other words, we observed that the protozoan..." Giardia lamblia Certain fungi frequently share the intestinal habitat. However, it is not yet possible to say whether the presence of one interferes with the existence and biological characteristics of the other,” explains the researcher from [organization name]. Laboratory of Taxonomy, Biochemistry and Bioprospecting of Fungi do IOC, Manoel Oliveira.
In addition to Oliveira's laboratory, the work also involved researchers from the Interdisciplinary Laboratory for Medical Research and the Thymus Research Laboratory of the Institute. The study also benefited from the collaboration of Maria Fantinatti, a specialist from the State University of Rio de Janeiro (UERJ).
The research was conducted in a community characterized by limited urban infrastructure and restricted access to basic sanitation.
According to Oliveira and Fantinatti, factors such as frequent contact with contaminated environments and an immune system still under development create favorable conditions for the simultaneous circulation of different microorganisms in the infant's intestine, increasing the risk of infections and imbalances that go beyond a single agent.
“A good analogy is to think of the gut as an ecosystem: when this environment undergoes changes—whether due to infection, malnutrition, or poor sanitary conditions—various microorganisms can benefit from this imbalance at the same time. Therefore, the study indicates a warning sign about the need to understand the impacts of this coexistence on the host, especially in children,” the researchers reflect.
Although some cases of giardiasis are asymptomatic, the presence of the protozoan alters the intestinal barrier and can cause imbalances in the microbiota — the collection of microorganisms that naturally live in the intestine — creating an environment favorable to the colonization of opportunistic fungi.
Among the microorganisms identified by the research, the high frequency of Candida parapsilosis It caught the attention of scientists.
This species is considered one of the main causes of invasive fungal infections in hospital settings and has gained prominence in recent years due to the increase in severe cases, especially in immunocompromised individuals.
Previous studies had already demonstrated that infection by Giardia lamblia It is associated with alterations in the bacterial microbiota. However, little was known about the composition of the fungal microbiota in these patients.
The new study fills part of this gap by mapping, for the first time, the fungi present in the intestines of children with giardiasis.
"Most of the literature focuses on bacterial dysbiosis caused by Giardia lamblia"However, the relationship between fungal microbiota and the presence of intestinal parasites is still poorly explored. Our work is pioneering in demonstrating, in Brazilian children in situations of social vulnerability, the frequent presence of fungi considered emerging or opportunistic," points out Fantinatti.
The researchers emphasize that, in real-world and socially vulnerable environments, it is difficult to determine which microorganism represents the primary infection. Even so, clinical observation indicated that the symptoms presented by the children were primarily consistent with giardiasis, suggesting that infection by the protozoan occurred first.
"Despite the small number of samples analyzed, the study is considered highly relevant as it inaugurates a new line of research in the field of neglected infectious diseases," Manoel points out.
These findings gain even more relevance in the current context, in which serious fungal infections have received greater attention from the scientific community following the Covid-19 pandemic.
In this scenario, the research of IOC It also engages with recent public policies aimed at tackling neglected diseases, such as the Healthy Brazil program of the Ministry of Health, which seeks to expand surveillance, diagnosis, and prevention actions in vulnerable territories.
"The study reinforces that children's intestinal health is a direct reflection of living conditions and that combating parasitic diseases requires actions that go beyond drug treatment, including public policies on sanitation, nutrition, and reducing social inequalities," Oliveira concludes.
A study coordinated by researchers from the Oswaldo Cruz Institute (IOC/Fiocruz) identified, for the first time, the coexistence of the protozoan Giardia lambliaThe study, which causes giardiasis, found opportunistic fungi of different species in the intestines of children, revealing that the disease may be part of a broader imbalance in the gut microbiome.
One of the most common intestinal infections in childhood, giardiasis can cause diarrhea, abdominal pain, gas, nausea, and loss of appetite. In young children, especially those in socially vulnerable settings, the infection can also be associated with weight gain difficulties and developmental impairments.
The research, published in the international scientific journal Frontiers in Cellular and Infection Microbiology, analyzed fecal samples from children attending a daycare center located in a community in the northern part of Rio de Janeiro.
The results revealed a novel association between giardiasis and certain potentially pathogenic yeast species. In total, stool samples from 25 children aged between 1 and 4 years were evaluated. Thirteen tested positive for giardiasis. Giardia lamblia.
Of these, 10 also showed growth of Candida parapsilosis, currently considered an emerging fungus of clinical importance.
In some cases, there was also coexistence with other species, such as Candida tropicalis, Candida krusei e Saccharomyces cerevisiaeCalled 'opportunistic fungi', these microorganisms typically do not cause symptoms when present in the gut microbiota, but tend to multiply excessively if the gut is weakened, whether by inflammation, low immunity, or alterations in internal balance.
According to the researchers, although the study design does not allow for a direct cause-and-effect relationship to be established between the protozoan infection and the presence of fungi, the findings raise an important alert about possible interactions between different microorganisms in the infant gut, especially in contexts of social vulnerability.
"The study reveals the possibility of coexistence, not a cause-and-effect relationship. In other words, we observed that the protozoan..." Giardia lamblia Certain fungi frequently share the intestinal habitat. However, it is not yet possible to say whether the presence of one interferes with the existence and biological characteristics of the other,” explains the researcher from [organization name]. Laboratory of Taxonomy, Biochemistry and Bioprospecting of Fungi do IOC, Manoel Oliveira.
In addition to Oliveira's laboratory, the work also involved researchers from the Interdisciplinary Laboratory for Medical Research and the Thymus Research Laboratory of the Institute. The study also benefited from the collaboration of Maria Fantinatti, a specialist from the State University of Rio de Janeiro (UERJ).
The research was conducted in a community characterized by limited urban infrastructure and restricted access to basic sanitation.
According to Oliveira and Fantinatti, factors such as frequent contact with contaminated environments and an immune system still under development create favorable conditions for the simultaneous circulation of different microorganisms in the infant's intestine, increasing the risk of infections and imbalances that go beyond a single agent.
“A good analogy is to think of the gut as an ecosystem: when this environment undergoes changes—whether due to infection, malnutrition, or poor sanitary conditions—various microorganisms can benefit from this imbalance at the same time. Therefore, the study indicates a warning sign about the need to understand the impacts of this coexistence on the host, especially in children,” the researchers reflect.
Although some cases of giardiasis are asymptomatic, the presence of the protozoan alters the intestinal barrier and can cause imbalances in the microbiota — the collection of microorganisms that naturally live in the intestine — creating an environment favorable to the colonization of opportunistic fungi.
Among the microorganisms identified by the research, the high frequency of Candida parapsilosis It caught the attention of scientists.
This species is considered one of the main causes of invasive fungal infections in hospital settings and has gained prominence in recent years due to the increase in severe cases, especially in immunocompromised individuals.
Previous studies had already demonstrated that infection by Giardia lamblia It is associated with alterations in the bacterial microbiota. However, little was known about the composition of the fungal microbiota in these patients.
The new study fills part of this gap by mapping, for the first time, the fungi present in the intestines of children with giardiasis.
"Most of the literature focuses on bacterial dysbiosis caused by Giardia lamblia"However, the relationship between fungal microbiota and the presence of intestinal parasites is still poorly explored. Our work is pioneering in demonstrating, in Brazilian children in situations of social vulnerability, the frequent presence of fungi considered emerging or opportunistic," points out Fantinatti.
The researchers emphasize that, in real-world and socially vulnerable environments, it is difficult to determine which microorganism represents the primary infection. Even so, clinical observation indicated that the symptoms presented by the children were primarily consistent with giardiasis, suggesting that infection by the protozoan occurred first.
"Despite the small number of samples analyzed, the study is considered highly relevant as it inaugurates a new line of research in the field of neglected infectious diseases," Manoel points out.
These findings gain even more relevance in the current context, in which serious fungal infections have received greater attention from the scientific community following the Covid-19 pandemic.
In this scenario, the research of IOC It also engages with recent public policies aimed at tackling neglected diseases, such as the Healthy Brazil program of the Ministry of Health, which seeks to expand surveillance, diagnosis, and prevention actions in vulnerable territories.
"The study reinforces that children's intestinal health is a direct reflection of living conditions and that combating parasitic diseases requires actions that go beyond drug treatment, including public policies on sanitation, nutrition, and reducing social inequalities," Oliveira concludes.
The non-profit reproduction of the text is allowed as long as the source is cited (Comunicação / Instituto Oswaldo Cruz)
 |
 |
