Scientists wanted to know if taking probiotics by mouth could help the body fight a parasitic infection called Leishmania. They gave mice probiotics and then tested how well their immune cells could fight the parasite in the lab. The results showed that probiotics did help reduce infection in immune cells, especially in male mice—one type reduced infection by 27%. However, probiotics didn’t make antiparasitic medicines work better. This early research suggests probiotics might play a role in fighting certain parasitic diseases, but more studies are needed before doctors could recommend this as a treatment.

The Quick Take

  • What they studied: Whether taking probiotics (beneficial bacteria) by mouth could help the body’s immune cells fight a parasitic infection called Leishmania amazonensis.
  • Who participated: Laboratory mice (both male and female) were given probiotics orally, then their immune cells were tested against the parasite in controlled lab conditions.
  • Key finding: Mice that received one type of probiotic (PB8) showed 27% less infection in their immune cells compared to mice without probiotics. A second probiotic type (Bifilac) showed a smaller 12% reduction. However, probiotics didn’t improve how well antiparasitic medicines worked.
  • What it means for you: This suggests probiotics might help your body’s natural defenses against certain parasitic infections, but this is very early research in mice. Don’t expect probiotics to replace medical treatment for parasitic diseases. More research in humans is needed before any medical recommendations can be made.

The Research Details

Scientists conducted a laboratory experiment using mice to test how probiotics affect parasitic infection. First, they gave mice probiotics to drink for a period of time. Then they removed immune cells (called macrophages) from the mice’s bodies and infected these cells with a parasite called Leishmania amazonensis in controlled lab dishes. This allowed them to see how well the immune cells from probiotic-treated mice could handle the parasite compared to cells from untreated mice.

The researchers tested two different probiotic formulations: one with multiple bacterial strains (PB8) and one with fewer strains (Bifilac). They also tested whether antiparasitic medicines worked better in cells from probiotic-treated mice. Finally, they measured inflammatory chemicals released by the immune cells to understand how the immune system was responding.

This research approach is important because it bridges the gap between what happens in the body and what scientists can control in the lab. By giving probiotics to living mice first, then testing their immune cells in controlled conditions, researchers could see if probiotics actually change how immune cells function—not just whether they’re present. This helps determine if probiotics have real biological effects worth studying further in humans.

This is laboratory research in mice, which is an early stage of scientific investigation. The study was published in a scientific journal, suggesting it went through expert review. However, results in mice don’t always translate to humans, so these findings are preliminary. The sample size of mice wasn’t specified in the available information, which makes it harder to assess how reliable the results might be. The statistical significance (p < 0.05) for the main findings suggests the results weren’t due to chance, but the lack of improvement with medicines and the non-significant trends in immune response suggest the effects may be modest.

What the Results Show

The main finding was that probiotics reduced how much the parasite could infect immune cells in the lab. When mice received the PB8 probiotic, their immune cells showed 27% less infection compared to cells from untreated mice. The Bifilac probiotic showed a smaller but still measurable 12% reduction in infection. These reductions were statistically significant, meaning they were unlikely to have happened by chance.

Interestingly, the researchers found no major differences between male and female mice in how probiotics affected infection rates, though the effect was slightly stronger in males. This suggests probiotics might work similarly regardless of sex, at least in this mouse model.

When the researchers tested whether probiotics made antiparasitic medicines work better, they found no improvement. Two different medicines (miltefosine and N6-methyltubercidin) worked the same way in cells from probiotic-treated and untreated mice. This suggests probiotics and these medicines might work through different mechanisms and don’t enhance each other’s effectiveness.

The study also measured inflammatory chemicals that immune cells release when fighting infection. When immune cells encountered the parasite, they produced three key inflammatory chemicals: TNF, MCP-1, and IL-6. These are the body’s natural alarm signals that help coordinate immune responses. In mice that received the PB8 probiotic, there was a trend toward higher levels of TNF (about 43% higher) and IL-6 (about 52% higher) in male mice, suggesting the immune system might be mounting a stronger response. However, these increases weren’t statistically significant, meaning they could have occurred by chance. This suggests probiotics might enhance immune activation, but the effect is subtle and needs further investigation.

Previous research has shown that the microbiome (the community of bacteria in our gut) plays an important role in how our immune system works. Dysbiosis (an imbalance in these bacteria) has been linked to various health problems, including potentially worse outcomes with infections. This study adds to that knowledge by showing that probiotics can actually influence how immune cells respond to parasitic infection. However, the modest effects observed here (12-27% reduction) are smaller than some researchers might have expected, suggesting that probiotics alone may not be a complete solution for parasitic infections.

This study has several important limitations to consider. First, it was conducted entirely in laboratory mice, not humans, so the results may not apply to people. Second, the immune cells were tested in lab dishes (ex vivo), not inside living bodies, which is a simplified environment. Third, the study doesn’t specify how many mice were used, making it difficult to assess how reliable the findings are. Fourth, the improvements in immune response (the trend toward higher TNF and IL-6) weren’t statistically significant, meaning they might not be real effects. Finally, the study only tested two probiotic formulations, so results might differ with other probiotic types or doses.

The Bottom Line

Based on this early research, probiotics should NOT be used as a replacement for proven antiparasitic medicines if you have a parasitic infection like leishmaniasis. The evidence is preliminary and limited to laboratory studies. If you live in an area where Leishmania is common or have been exposed to it, consult a doctor about proven prevention and treatment options. Taking probiotics for general gut health may have other benefits, but don’t expect them to treat parasitic infections. (Confidence level: Low—this is early-stage research)

This research is most relevant to people living in or traveling to tropical regions where Leishmania parasites are found (parts of South America, Africa, Asia, and the Mediterranean). It’s also of interest to researchers studying parasitic diseases and the role of the microbiome in infection. People with general interest in how probiotics work will find this informative. However, this research should NOT influence treatment decisions for anyone currently infected with a parasitic disease—always follow your doctor’s recommendations.

This is very early research, so there’s no realistic timeline for practical applications. Laboratory findings typically take 5-10+ years to translate into human treatments, if they translate at all. Don’t expect probiotics to become a standard parasitic infection treatment based on this study alone. Much more research, including human studies, would be needed before any clinical recommendations could be made.

Want to Apply This Research?

  • If you take probiotics, track your daily probiotic intake (type, strain, and CFU count) alongside any gastrointestinal symptoms or general wellness markers. Note the specific probiotic formulation used, as different strains may have different effects.
  • Users interested in parasitic disease prevention in high-risk areas could use the app to: (1) log probiotic supplementation as part of a broader wellness routine, (2) track travel to endemic regions, and (3) set reminders for medical check-ups in areas where parasitic diseases are common. However, emphasize that this is supplementary to, not a replacement for, medical prevention strategies.
  • For long-term tracking, users should monitor overall digestive health and immune function markers (like frequency of infections) while taking probiotics, but recognize that this study doesn’t provide evidence that probiotics specifically prevent parasitic infections. Any suspected parasitic infection should trigger immediate medical consultation rather than reliance on app-tracked probiotic use.

This research is preliminary laboratory work in mice and does not provide evidence for treating parasitic infections in humans. Probiotics should not be used as a substitute for proven medical treatment of leishmaniasis or other parasitic diseases. If you suspect you have a parasitic infection, consult a healthcare provider immediately for proper diagnosis and treatment. This article is for educational purposes only and should not be considered medical advice. Always follow your doctor’s recommendations for preventing and treating parasitic infections, especially if you live in or travel to areas where these diseases are common.