Researchers in Rwanda discovered that drinking raw (unpasteurized) milk from cows can expose families to a serious disease called brucellosis. The study looked at 330 households and found that nearly half drank raw milk. About 1 in 7 households had at least one person drinking raw milk from cows that tested positive for the Brucella bacteria. The risk was much higher in families that let cows roam freely compared to those keeping cows in enclosed areas. Farmers who work directly with the cows faced the highest risk. The findings suggest that education about the dangers of raw milk is urgently needed in Rwanda.

The Quick Take

  • What they studied: Whether families in Rwanda who drink raw milk from their own cows are at risk of catching brucellosis, a disease that spreads from animals to humans
  • Who participated: 330 households in Rwanda—198 families with cows kept in enclosed areas and 132 families with cows that roam freely. Researchers tested the milk and asked families about their drinking habits
  • Key finding: About 14% of all households had someone drinking raw milk from cows that tested positive for Brucella bacteria. This risk was 70 times higher in families with roaming cows (35%) compared to families with enclosed cows (0.5%)
  • What it means for you: If you live in Rwanda and drink raw milk from your own cows, especially if they roam freely, you have a real risk of getting brucellosis. Boiling or pasteurizing milk before drinking it would eliminate this risk. This is particularly important for farmers who handle the cows daily

The Research Details

Researchers conducted a cross-sectional study, which is like taking a snapshot in time rather than following people over months or years. They visited 330 households in Rwanda and collected information in two ways: first, they asked families questions about their milk drinking habits using a questionnaire, and second, they tested samples of bulk milk from each farm using a special laboratory test (called i-ELISA) to check for Brucella bacteria.

The households were divided into two groups based on how they raised cattle: 198 households practiced ‘zero grazing’ (keeping cows in enclosed areas and bringing food to them) and 132 households practiced ‘open grazing’ (letting cows roam freely to find their own food). This comparison was important because the researchers suspected the grazing method might affect disease risk.

The researchers then used statistical analysis to identify which factors were most strongly connected to the risk of exposure to Brucella through raw milk consumption.

This research approach is important because it provides a real-world picture of the actual risk in Rwandan communities right now. By testing actual milk samples and asking families about their real behaviors, the researchers could identify exactly which households and which people face the greatest danger. This type of evidence is crucial for public health officials to decide where to focus education and prevention efforts.

The study’s strengths include a reasonable sample size of 330 households and the use of both questionnaires and laboratory testing, which provides objective evidence rather than just relying on what people remember. However, the study was conducted at one point in time, so it shows risk at that moment but doesn’t prove that drinking raw milk definitely causes brucellosis in these families. The study also doesn’t explain why open grazing is riskier—it could be due to different farming practices, animal health, or milk handling methods. The researchers didn’t report the journal’s impact factor, which would help assess the publication’s prestige.

What the Results Show

Nearly half of all surveyed households (49%) reported drinking raw milk. When researchers tested the milk, they found that 14% of all households had at least one person drinking raw milk from cows that tested positive for Brucella bacteria. This means roughly 1 in 7 households had exposure to the disease through their milk.

The most striking finding was the huge difference between the two grazing systems. In households with roaming cows (open grazing), 35% had both raw milk consumption and positive Brucella test results. In contrast, only 0.5% of households with enclosed cows (zero grazing) had this combination. This 70-fold difference is statistically significant, meaning it’s very unlikely to be due to chance.

When looking at individual people rather than households, 4.8% of all household members surveyed were exposed to Brucella through raw milk consumption. However, the farmers themselves—the people who work directly with the cows—faced much higher risk. Farmers were about 51 times more likely to be exposed compared to other household members.

The research revealed that the practice of open grazing was significantly associated with both raw milk consumption and the presence of Brucella in that milk. This suggests that how cattle are managed directly affects the safety of the milk. The study also showed that cattle keepers (farmers) are the most vulnerable group, likely because they have more contact with the animals and may be more likely to drink raw milk from their own cows.

This study adds important local evidence to what researchers already know about brucellosis worldwide. Brucellosis is recognized globally as a serious zoonotic disease (one that spreads from animals to humans), and raw milk has long been identified as a major transmission route. This Rwanda study confirms that the problem exists in East Africa and identifies specific risk factors relevant to Rwandan farming practices. The finding that enclosed cattle systems are much safer aligns with international recommendations for disease prevention.

The study has several important limitations. First, it was conducted at only one point in time, so it shows a snapshot rather than tracking whether people actually got sick. Second, the study doesn’t explain why open grazing is riskier—it could be due to animal health differences, milk handling practices, or other factors not measured. Third, the study relied on people’s honest answers about their milk drinking habits, which might not always be accurate. Finally, the results are specific to Rwanda and may not apply to other countries with different farming practices or climates.

The Bottom Line

Based on this research, the strongest recommendation is to avoid drinking raw milk, especially in Rwanda where the risk has been documented. Boiling milk to at least 63°C (145°F) for 30 minutes, or using pasteurized milk, will eliminate the Brucella bacteria. For farmers in Rwanda, switching from open grazing to zero grazing (enclosed cattle systems) appears to significantly reduce risk. These recommendations have high confidence because they’re based on actual testing of milk and documented cases of exposure. People should also be aware that brucellosis symptoms (fever, fatigue, joint pain) can take weeks to appear, so any illness after raw milk consumption should be reported to a doctor.

This research is most important for people in Rwanda, particularly those in rural areas who keep cattle and drink raw milk. Farmers and their families should be especially concerned because they face the highest exposure risk. Public health officials in Rwanda and other East African countries should use this information to design education campaigns. However, the findings may also be relevant to other countries with similar cattle-raising practices. People who don’t keep cattle or who drink only pasteurized milk face minimal risk from this source.

If someone stops drinking raw milk today, their risk of brucellosis exposure drops to zero immediately. However, if someone has already been exposed, symptoms typically appear within 2-8 weeks. If someone switches from open grazing to zero grazing cattle practices, the risk reduction should be noticeable within the first season of the new system, though it may take time to see full benefits as animal health improves.

Want to Apply This Research?

  • Users in Rwanda or similar regions could track their raw milk consumption by logging each time they drink unpasteurized milk and noting the source (which farm or household). They could also track any symptoms like fever, fatigue, or joint pain that appear in the following weeks, which would help identify potential exposure early.
  • The app could help users transition from raw to pasteurized milk by: (1) setting a goal to eliminate raw milk consumption, (2) providing reminders about boiling milk to safe temperatures, (3) tracking days without raw milk consumption as a streak, and (4) offering recipes that use pasteurized milk as alternatives to traditional raw milk preparations.
  • For long-term tracking, users could monitor their milk source weekly (recording whether it’s raw or pasteurized), track any illness symptoms monthly, and set quarterly check-ins to assess whether they’ve successfully switched to safer milk practices. Users could also track whether their household has transitioned to zero grazing cattle practices if applicable.

This research describes the risk of brucellosis exposure through raw milk consumption in Rwanda but does not diagnose or treat any individual’s health condition. If you consume raw milk and develop symptoms such as fever, fatigue, joint pain, or night sweats, consult a healthcare provider immediately and mention your raw milk consumption. Brucellosis is treatable with antibiotics when caught early. This information is for educational purposes and should not replace professional medical advice. Pregnant women, young children, elderly individuals, and immunocompromised people should be especially cautious about raw milk consumption. Always consult with local health authorities or a doctor about food safety practices in your specific region.