Enzyme-linked immunosorbent assay, not agglutination, is the test of choice for the diagnosis of neurobrucellosis

Bovine brucellosis - a comprehensive review

Brucellosis is a zoonotic disease of great animal welfare and economic implications worldwide known since ancient times. The emergence of brucellosis in new areas as well as transmission of brucellosis from wild and domestic animals is of great significance in terms of new epidemiological dimensions. Brucellosis poses a major public health threat by the consumption of non-pasteurized milk and milk products produced by unhygienic dairy farms in endemic areas. Regular and meticulous surveillance is essentially required to determine the true picture of brucellosis especially in areas with continuous high prevalence. Additionally, international migration of humans, animals and trade of animal products has created a challenge for disease spread and diagnosis in non-endemic areas. Isolation and identification remain the gold standard test, which requires expertise. The advancement in diagnostic strategies coupled with screening of newly introduced animals is warranted to control the disease. Of note, the diagnostic value of miRNAs for appropriate detection of B. abortus infection has been shown. The most widely used vaccine strains to protect against Brucella infection and related abortions in cattle are strain 19 and RB51. Moreover, it is very important to note that no vaccine, which is highly protective, safe and effective is available either for bovines or human beings. Research results encourage the use of bacteriophage lysates in treatment of bovine brucellosis. One Health approach can aid in control of this disease, both in animals and man.

Isolated neurobrucellosis-characteristic clinical and laboratory features

To report various neurological syndromes, CSF findings, imaging and diagnostic methods used in neurobrucellosis patients admitted in our Neurology department over a period of 6 years. Case records of patients admitted to our department from August 2014 to May 2020 were searched for neurobrucellosis and data were obtained. A total of 19 patients were diagnosed as neurobrucellosis over a period of 6 years. Ten patients had chronic meningitis, five had VIII nerve involvement, one had optic neuritis, two had acute meningitis, one had subacute meningitis, four had myelopathy, five had polyradiculitis and two had spondylodiscitis. CSF was abnormal in 17 patients. Neutrophilic pleocytosis was seen in 12 patients who included nine patients with chronic symptomatology. Brain imaging was abnormal in three chronic meningitis patients. One had diffuse meningeal enhancement, another had hydrocephalus while the third patient had meningeal enhancement with basal exudates and contrast enhancement of bilateral VIII nerve. One of the patients of acute meningitis had hydrocephalus while the other one had bilateral T2/FLAIR hyperintensities with enhancement of meninges and leptomeningeal vessels. Elevated antibody titers only in serum was seen in six patients while elevated antibody titers only in CSF was seen in seven patients. Four patients had elevated antibody titers in both serum and CSF. CSF culture was positive in three patients. Neurobrucellosis is a rare clinical complication of brucellosis but may pose a problem in diagnosis as it can mimic tuberculosis. Involvement of VIII nerve and neurophilic pleocytosis in CSF despite chronic symptomatology can be diagnostic clues favoring neurobrucellosis.

A comparison of immuncapture agglutination and ELISA methods in serological diagnosis of brucellosis

BACKGROUND

Different serological tests are used in serologic diagnosis of brucellosis. The most widely used of these are Standard Tube Agglutination and Coombs anti-brucella tests. Whereas ELISA Ig M and Ig G tests have been in use for a long time, immuncapture agglutination test has been recently introduced and used in serological diagnosis. The aim of this study was to compare diagnostic values of ELISA Ig M and Ig G and immuncapture agglutination tests with Coombs anti-brucella test.

METHODS

Sera from 200 patients with presumptive diagnosis of brucellosis were included into the study. Coombs anti-brucella test, ELISA Ig M and Ig G tests and Immuncapture test were investigated in these sera. Then, sensitivity, specificity, negative predictive and positive predictive values were calculated.

RESULTS

Sensitivity, specificity, negative predictive and positive predictive values were found to be 90.6%, 76.3%, 94.2%, and 65.9% respectively for the Immuncapture test, whereas they were found to be 73.7%, 58.9%, 84.2%, and 42.8% for Ig G and 72.2%, 67.8%, 85.2%, and 48.7% for Ig M. The Immuncapture test was found to be compatible with ELISA Ig M and Ig G tests but it was statistically incompatible with Coombs anti-brucella test.

CONCLUSIONS

Immuncapture agglutination test yields similar results to those of Coombs anti-brucella test. This test is a useful test by virtue of the fact that it determines blocking antibodies in the diagnosis and follow-up of brucellosis.

Brucellosis in India - a review

Brucellosis is an important re-emerging zoonosis with a worldwide distribution. It is still an uncontrolled serious public health problem in many developing countries including India. Brucellosis in India is yet a very common but often neglected disease. Currently, Brucella melitensis accounts for most recorded cases globally with cattle emerging as a important reservoir with the few cases of B. suis. Isolated cases of non-terrestrial brucellosis and continuing transmission from wild animals have raised important epidemiological issues. Routine serological surveillance along with high clinical suspicion and screening of family members of index cases would be essential in delineating the real magnitude of human brucellosis in endemic countries. Increased business and leisure travel to endemic countries have led to diagnostic challenge in non-endemic areas. Laboratory testing is indispensable for diagnosis. Advances in newer rapid, sensitive, and specific testing methodologies and alternate treatment strategies are urgently needed. A safe and effective vaccine in human is not yet available. Prevention is dependent upon increasing public awareness through health education programmes and safe livestock practices. Active co-operation between health and veterinary services should be promoted. This review collates world literature and its impact to the discovery, isolation and diagnosis and epidemiology along with the control measures adapted in the Indian scenario.

Neurobrucellosis mimicking cerebral tumor: case report and literature review

We are reporting a case of neurobrucellosis that was clinically and radiologically indistinguishable from a cerebral tumor. The histological diagnosis was granulomatous encephalitis. The diagnosis was established by enzyme-linked immunosorbent assay (ELISA), detecting high levels of Ig G and Ig M Brucella antibodies in the serum and the cerebrospinal fluid. We suggest that patients with granulomatous encephalitis, without a clear etiological agent, should be studied for Brucella.

Neurobrucellosis in an endemic area of brucellosis

Central nervous system involvement occurs less than 5% of patients with brucellosis. A prospective analysis of 73 patients with brucellosis identified 13 (17.8%) neurobrucellosis cases from February 2001 to May 2002. 10 patients had chronic meningitis and 3 acute meningitis. Two patients had only psychiatric disorders. Cranial nerve involvement was observed in 3 patients (6th, 7th and 8th nerves). Three patients had positive blood cultures and 3 others had positive cerebrospinal fluid (CSF) cultures. 12 patients had positive agglutination titres in CSF. All patients received antibiotic therapy with ceftriaxone, rifampicin and doxycycline initially, and after 1 month they were continued with rifampicin and doxycycline up to 4 months. All patients were completely cured. Hearing loss developed in 1 patient as a sequela.

Evaluation of PCR, culture and serology for the diagnosis of acute human brucellosis

BACKGROUND

The diagnosis of brucellosis is frequently difficult to establish. This is not only because clinically, the disease can mimic any infectious and noninfectious disease, but also because the established diagnostic methods are not always successful. In this study, we have tried to evaluate PCR techniques in the diagnosis of brucellosis in comparison to conventional techniques.

PATIENTS AND METHODS

Fifty peripheral blood samples from the following groups were collected: patients with brucellosis (17); patients with febrile illnesses due to factors other than brucella etiology (19); symptomatic occupationally exposed persons (9); and healthy volunteers (5). The last three groups were considered controls. Among the 17 Brucella samples, only 14 were obtained before treatment was begun. The samples were tested by serology, using the standard tube agglutination method (STA), blood culture using Bactec machines, and PCR using primer pair to amplify a 223-bp region within a gene coding for a 31-kD Brucella antigen. Diagnosis of brucellosis was based on compatible clinical picture in addition to positive blood culture and/or positive serology.

RESULTS

Of the 17 blood samples from patients with brucellosis, eight were culture positive for Brucella species, and all showed high titer antibrucella antibodies. Only 14 of them were positive by PCR, and these were the samples submitted before initiation of therapy, representing 100% sensitivity. Among the 33 controls, blood culture was negative for Brucella in all of them, while one sample showed high-titer antibrucella antibodies. The latter was from the febrile illnesses group. PCR-based assay was able to detect four bands in the controls, all of which were from the occupationally exposed asymptomatic group.

CONCLUSION

In view of the several advantages of PCR over the conventional methods for the diagnosis of brucellosis, such as speed, safety, high sensitivity and specificity, the technique might be considered for laboratory diagnosis of brucellosis. However, for the evaluation of asymptomatic highly exposed persons, PCR might be considered complementary to the traditional methods and followed up by serology and/or culture.