LETTER TO EDITOR
Year : 2009 | Volume
: 52 | Issue : 3 | Page : 457--458
Seroprevalence of Brucella agglutinins: A pilot study
S Nagarathna1, S Sharmada2, HB Veena Kumari1, N Arvind1, P Sundar3, S Sangeetha3,
1 Department of Neuromicrobiology, NIMHANS, Bangalore, India
2 Department of Biotechnology, Manipal Life Sciences Centre, Manipal, India
3 Department of Neuropathology, NIMHANS, Bangalore, India
Department of Neuromicrobiology, NIMHANS, Hosur Road, Bangalore - 29
|How to cite this article:|
Nagarathna S, Sharmada S, Veena Kumari H B, Arvind N, Sundar P, Sangeetha S. Seroprevalence of Brucella agglutinins: A pilot study.Indian J Pathol Microbiol 2009;52:457-458
|How to cite this URL:|
Nagarathna S, Sharmada S, Veena Kumari H B, Arvind N, Sundar P, Sangeetha S. Seroprevalence of Brucella agglutinins: A pilot study. Indian J Pathol Microbiol [serial online] 2009 [cited 2021 Jun 17 ];52:457-458
Available from: https://www.ijpmonline.org/text.asp?2009/52/3/457/55036
Brucellosis is a zoonotic disease that continues to be of public health and economic concern in many parts of the world.  The reported incidence of human brucellosis worldwide in endemic areas varies widely, from 200 per lakh population .The true incidence however, is unknown and it has been estimated that it may be 25 times higher than the reported incidence due to misdiagnosis and underreporting. Countries like the Mediterranean basin, the Arabian Gulf, the Indian subcontinent and parts of Mexico as well as Central and South America, are especially endemic for human brucellosis. 
Human brucellosis is known for protean manifestations, the most common presenting symptom being fever. An unexplained fever is one of the indications of brucellosis and brucella agglutination test is one of the screening panels of pyrexia of unknown origin (PUO). Serological investigation of the patients is of paramount importance for diagnosis and future management of the patient. Hence, it is important to know the background prevalence of Brucella antibodies in those who may not be exposed to brucellosis, which might give an overview of the endemicity of the disease. Therefore, the major objective of the present study was to investigate the background prevalence of brucella agglutinins against brucella antigen in blood donor population.
In this prospective study, the samples of blood donors were obtained from Transfusion Medicine Centre, over a period of one month.
A total of 353 samples were analyzed for the presence of brucella antibodies. The age group ranged from 18 to 56 years with 283 males and 70 females giving a male: female ratio of 4:1.
All blood samples were analyzed using Rose Bengal Plate Test (RBPT) and Serum Tube Agglutination Test (STAT). The antigens were procured from Division of Biological Products, Indian Veterinary Research Institute (IVRI), Izatnagar, Uttar Pradesh. The tests were carried out as per the protocol provided by the manufacturers, which included positive and negative controls. Human brucellosis is a disease endemic in most of the developing countries manifesting as acute, subacute and chronic disease. The transmission of this infection and its predominance in a particular region depends upon several factors like food habits, methods of processing milk and milk products, social customs and husbandry practices, socioeconomic status and environmental hygiene. Due to its varied manifestations, there should be a high index of clinical suspicion for the definitive diagnosis of brucellosis.
The reported incidence and prevalence varies from country to country. A range of prevalence of 1-3.2% from Turkey and 4.5% from Saudi Arabia, has been recorded.  Several publications indicate that human brucellosis can be a fairly common disease in India.  Varying prevalence of brucella agglutinins, has been reported in different types of population, like 8.5% among dairy personnel, 4.2% in aborted women and 8.5% in human cases in Gujarat. 
In our study, out of 353 samples, 52 samples (14.7%) were found to be positive by RBPT method and four samples (1.1%) positive by STAT method, suggesting that RBPT is highly sensitive but less specific. Our results indicate that the specificity of the slide test is enhanced by subjecting the samples to STAT method (4/52=76%). Hence, STAT may remain as the most popular diagnostic tool for brucellosis, worldwide.
There is a paucity of published literature on human brucellosis in India. To the best of our knowledge, there are only few publications projecting the seroprevalence of brucellosis among blood donors and there are none from this part of the country. Vaishnavi et al. , reported a similar study of low seroprevalence of one (0.36%) amongst blood donors at Chandigarh. 
In the present study, positivity in four (1.1%) (statistically not significant) samples may be envisaged to be due to consumption of raw milk, travel to regions that are endemic to brucellosis or a brief contact with an infected animal or being from rural background or may be due to cross-reacting antibodies such as Vibrio cholerae, Yersinia enterocolitica etc.
Our study reports a low seroprevalence of antibodies against brucella agglutinogens, hence may not be suggestive of endemicity of the disease in Bangalore. However, further wide prospective study on a large cluster of samples on long-term basis, needs to be conducted in order to assess the status of the disease in this area.
The authors would like to acknowledge Dr. S. K. Shankar, Professor and Head, Department of Neuropathology, NIMHANS for providing the samples, Dr. S. K. Amarnath, Manipal Cure and Care for Statistical Analysis, Dr. M.D Venkatesha, Institute of Animal Health and Veterinary Biologicals, Bangalore, for technical support.
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