Brucellosis: what you need to know if you drink raw milk or eat homemade cheese

What is brucellosis and how do people catch it?

Brucellosis is caused by Brucella bacteria, which live naturally in cattle, sheep, goats and camels. People become infected mainly by consuming unpasteurised milk or products made from it, including fresh homemade cheese, cream and unprocessed butter. A 2025 study in Nature Communications found that camel milk is a significantly underappreciated source of brucellosis in Arab rural communities, with infection rates higher than previously recognised.

Infection can also spread through inhaling contaminated particles near animal pens, or by handling animal tissue during slaughter or birth. Farmers, veterinarians, abattoir workers and shepherds are at higher occupational risk than the general population. Transmission from person to person is extremely rare.

Across the Middle East and North Africa, brucellosis causes more human illness than almost any other bacterial zoonosis. Syria, Jordan, Iraq and Saudi Arabia report among the highest rates in the world, driven by the cultural practice of making and sharing fresh dairy products within households and communities.

What does brucellosis feel like?

The time between exposure and symptoms ranges from one to eight weeks. The defining feature is the undulant fever: temperature climbs in the late afternoon or evening to 39 or 40 degrees Celsius, accompanied by drenching sweating, then falls gradually by morning leaving a fleeting sensation of improvement before the cycle repeats. This wave pattern gave the disease its older name, undulant fever.

Joint and muscle pain is almost universal, particularly affecting the knees, hips and lower back. Fatigue, headache and loss of appetite are consistent. The spleen and liver may enlarge, which can feel like a heaviness or discomfort in the upper abdomen.

The clinical picture looks strikingly like influenza, typhoid or other febrile illnesses, which is why diagnosis is frequently delayed by weeks. Many patients treat themselves with paracetamol or assume a viral illness will resolve. The key differentiator is the evening fever pattern combined with a dietary or occupational exposure history.

Which tests diagnose brucellosis?

A standard blood count (CBC) will not diagnose brucellosis. The primary diagnostic test is the Rose Bengal test for rapid screening, confirmed by the Wright serum agglutination test (SAT). The Wright test is considered positive when the titre reaches 1:160 or above in endemic regions, though laboratory reference ranges vary. A 2015 study in the journal Infection noted that detectable antibody titres can persist for years after successful treatment, which means a positive result must always be interpreted alongside symptoms and exposure history.

Timing matters. During the first week of illness, antibody tests may be falsely negative because the immune response is still building. If clinical suspicion remains strong, repeat testing after one to two weeks is appropriate. Blood culture is the most specific confirmatory method, but takes two to four weeks and requires a specialised laboratory, which limits its practicality in many regional settings.

PCR-based testing offers faster results and high specificity where available. When you go for testing, tell the laboratory technician clearly that brucellosis is suspected. The standard blood request form often does not prompt for these specific tests automatically.

How is brucellosis treated, and for how long?

Because Brucella bacteria survive inside human cells, a single antibiotic rarely achieves cure. The internationally recommended approach combines two drugs. The most widely used regimen pairs doxycycline for six weeks with rifampicin for six weeks, or with intramuscular streptomycin for the first two to three weeks. Al-Tawfiq and Memish, reviewing treatment evidence in 2013, confirmed that combination therapy significantly reduces relapse rates compared with monotherapy.

Uncomplicated brucellosis is treated for six weeks. Complications involving the spine, heart valves, or nervous system may require three months or longer, with the specific regimen chosen according to the site and severity of infection. Starting treatment promptly after diagnosis reduces the risk of the infection becoming established in joints or the spine.

A 2025 study published in PLoS Neglected Tropical Diseases, conducted in an endemic region in Saudi Arabia, documented relapse in a meaningful proportion of patients and found that incomplete treatment courses were among the strongest predictors. The practical message is consistent: take both drugs for the full prescribed duration even when you feel well by week two or three.

When does brucellosis become an emergency?

Most cases are managed safely as outpatients with oral antibiotics. However, several complications require urgent medical attention. Spinal brucellosis (spondylitis) causes escalating back pain and can progress to weakness in the legs or difficulty passing urine. It accounts for ten to thirty percent of complications in chronic cases and needs imaging and a prolonged antibiotic course.

Endocarditis, or infection of the heart valves, is rare but the most life-threatening complication. It may require surgery in addition to months of antibiotics. Neurobrucellosis, involving the brain and meninges, presents with severe headache, stiff neck, and confusion and is a medical emergency.

How can brucellosis be prevented?

Pasteurisation destroys Brucella completely. Commercially produced milk sold in sealed containers from reputable dairies is safe. The risk lies almost entirely in raw milk purchased directly from farms, and in fresh cheeses made without pasteurisation. The longer a fresh cheese is salted and left to drain, the greater the reduction in bacterial load, but salting and aging alone do not reliably eliminate Brucella and cannot be relied upon as a safety measure.

The cultural value placed on fresh local dairy in many parts of the Middle East is understandable, and the advice to avoid it is often unwelcome. A practical middle ground for households that keep their own animals is to heat raw milk to a rolling boil for two minutes before consuming it or using it to make cheese. This is not perfect pasteurisation but substantially reduces the bacterial load.

Thorough cooking protects against meat-borne transmission. Organ meats such as liver and lung need to be cooked through with no remaining pink. For farmers, shepherds and abattoir workers, wearing rubber gloves during animal deliveries and when handling placental tissue is the most important single protective measure, as birth fluids carry the highest bacterial concentrations encountered in any occupational setting.

There is currently no approved human vaccine against brucellosis. Animal vaccination programmes, when applied consistently to national herds, reduce the reservoir of infection and protect the human population indirectly. In regions where animal vaccination is inconsistent or interrupted by conflict or supply disruption, the burden of prevention falls more heavily on individual dietary choices and occupational precautions.

Brucellosis in pregnancy

Brucellosis during pregnancy is associated with an increased risk of miscarriage and foetal death, particularly in the first and second trimesters. This makes early diagnosis especially important for pregnant women living in endemic areas or with a clear dietary exposure.

Treatment options are limited in pregnancy because doxycycline is contraindicated. Doctors must use alternative combinations such as rifampicin with co-trimoxazole, or rifampicin alone for milder cases, weighing the risks to the foetus against the consequences of untreated infection. Any pregnant woman who suspects brucellosis should discuss it with her doctor without delay.

Family members who shared the same food source should also be tested. A single meal of contaminated raw cheese can infect multiple people in a household at the same time, and some may have mild or atypical symptoms that are easy to dismiss.

Life during and after treatment

Fatigue is the most persistent and disabling symptom, often continuing for weeks after the fever resolves and antibiotics are working correctly. This is not a sign of treatment failure. The body is recovering from a deep intracellular infection, and rest is a legitimate part of that process. Returning to heavy physical work too early prolongs recovery and may cause a premature sense that the treatment is failing.

Doxycycline increases sun sensitivity considerably. In a climate where summer temperatures regularly exceed forty degrees and outdoor exposure is unavoidable, this side effect is practically significant. Wear protective clothing or apply sunscreen rated SPF 30 or above during treatment, particularly between April and October. Take doxycycline with a small meal or glass of milk to reduce the stomach irritation that leads some patients to skip doses.

Follow-up blood tests at three and six months after completing treatment are standard practice to check for relapse. Even with a successful course, antibody titres may remain mildly positive for a year or more because the immune system retains a memory of the infection. The follow-up interpretation should be done by the same physician who managed the initial episode, since interpreting a titre in isolation, without knowing the pre-treatment level, can lead to unnecessary concern or a second unnecessary course of treatment.

Rifampicin turns urine, sweat, tears and contact lenses orange-red. This is entirely expected and causes no harm, but patients who are not warned in advance sometimes stop taking the drug thinking something has gone wrong. Rifampicin also reduces the effectiveness of hormonal contraceptives, so women using the pill or patch should use additional contraception for the duration of treatment and for a further four weeks afterwards.

Tracking your recovery with Sihtak

Six weeks of twice-daily antibiotics is a long commitment, and it is easy to lose track of symptoms or forget whether you took today's dose. The Sihtak app lets you log your temperature each day, record how your joint pain and energy are progressing, and keep a medication diary to share with your doctor at the follow-up visit.

Documenting the pattern of your fever over several days, rather than relying on memory, makes it much easier for your doctor to judge whether the treatment is working and when it is safe to stop.

Sources

• Qureshi KA, Parvez A, Fahmy NA et al: Brucellosis: epidemiology, pathogenesis, diagnosis and treatment-a comprehensive review, Annals of medicine, 2023
• Holloway P, Gibson M, Holloway T et al: Camel milk is a neglected source of brucellosis among rural Arab communities, Nature communications, 2025
• Al-Tawfiq JA, Memish ZA: Antibiotic susceptibility and treatment of brucellosis, Recent patents on anti-infective drug discovery, 2013
• Bahabri I, Hakeem A, Alturki MS et al: Brucellosis relapse: Rate, patient characteristics, and clinical outcomes in an endemic region, PLoS neglected tropical diseases, 2025
• Andriopoulos P, Kalogerakou A, Rebelou D et al: Prevalence of Brucella antibodies on a previously acute brucellosis infected population, Infection, 2015
• World Health Organization: Brucellosis fact sheet, WHO EMRO