Summary

Thorough history taking and analysis of symptoms have proven to be very useful as Brucellosis despite being a major public health concern in India is often overlooked and misdiagnosed because of its confusing presentation and unavailability of confirmatory tests in endemic areas.

Brucellosis, a neglected zoonotic illness is associated with significant morbidity, especially in India, where a large portion of the population practices farming and is in close contact with animals. Contributory factors to the spread of the zoonotic disease include poor hygiene, illiteracy and poverty. B. melitensis and B. abortus are the prevalent species involved in human disease. Of the two, B. melitensis is a very dangerous species accountable for severe and prolonged disease which can also result in disability.

Clinical spectrum

Human brucellosis presents with protean manifestations such as fever and joint pains along with other manifestations of an influenza like or septicaemic illness, often with insidious onset. The main symptoms in humans are undulant fever, weight loss and night sweats. In endemic areas, brucellosis is one of the causes of fever of prolonged duration and one of the significant causes of pyrexia of unknown origin (PUO).

1. Brucellosis is marked by an acute or subacute febrile illness which can continue or develop into a chronically debilitating disease with severe complications. Malaise, anorexia, and prostration might be present along with intermittent or remittent fever.
2. Malodorous perspiration is considered as almost pathognomonic. Infection may be acute (<2 months) or subacute (2 to 12 months), or may progress to a chronic incapacitating disease with severe complications (>1 year).
3. Without any definite treatment, a patient may complain for weeks or months. Usually few or no objective signs are evident that particularly point to brucellosis.
4. Liver, spleen, and lymph nodes may be enlarged along with other signs related to the other systems of the organ.
5. Weakness, scrotal swelling and pain, chills, back pain decreased appetite, arthralgia, myalgia, weight loss, lethargy, headache, and psychological symptoms are the other common clinical symptoms of brucellosis.
6. Complications may be osteoarticular (40%), genitourinary, gastrointestinal, nervous, cardiovascular, skin and mucous membranes and respiratory.
7. Epididymoorchitis, spontaneous abortion, and hepatitis may also occur.
8. Central nervous system (CNS) involvement manifests as meningitis, encephalitis, meningoencephalitis, meningovascular disease, brain abscesses and demyelinating syndromes that occur in about 5-7% of the cases of B. melitensis infection.

Laboratory perspective

The only way to confirm the diagnosis of brucellosis is through blood test. Isolation and identification of Brucellae from clinical samples, antigen detection, and genome showcasing and detecting Brucella specific antibodies are the lab tools available.

Blood cultures may not always be positive even in ideal situations but they can definitely confirm the diagnosis of brucellosis. A rapid and reliable diagnostic alternative for diagnosing acute brucellosis is via dipstick assays such as the Brucella IgM and IgG lateral flow and latex agglutination. They both have been developed recently and for culture confirmed brucellosis, the lateral flow assay has a sensitivity and specificity of more than 95%.

The latex agglutination assay has a sensitivity of 89.1% and a specificity of 98.2% for initial serum samples of culture confirmed brucellosis patients. In centers without the expertise and facilities to execute the more difficult classic serologic tests, both these tests are perfect as field tests in remote areas and as point of care tests.

Available treatment options

1. Rifampicin 600 to 900 mg and Doxycycline 100 mg twice daily for a minimum of six weeks in adults is the recommended treatment by the World Health Organization for acute brucellosis. Doxycycline 4 mg / kg / day and rifampicin 10 mg/kg /day orally for six weeks can be given in combination to treat childhood brucellosis.
2. A triple regimen used popularly in many countries includes Trimethoprim-sulfamethoxazole.
3. Quinolones can also be used as various combinations with ciprofloxacin and ofloxacin have shown similar efficacy when compared to the classic regimens.
4. Brucellosis can be safely treated in pregnancy using Rifampicin with or without a combination of cotrimoxazole.
5. A repeat course of the usual antibiotic regimen can be used for relapses which are often milder in severity and occur about 10% of the times. Most complications of brucellosis such as spondylitis, osteomyelitis, neurobrucellosis and endocarditis also require combination therapy but for longer duration.
6. Some complications such as neurobrucellosis will require combination therapy with two or three drugs that may include doxycycline, rifampicin and trimethoprim-sulfamethoxazole.