Bioterrorism : A Public Health Perspective.

The intentional release or threat of release of biologic agents (i.e. viruses, bacteria, fungi or their toxins) in order to cause disease or death among human population or food crops and livestock to terrorize a civilian population or manipulate the government in the present scenario of increased terrorist activity has become a real possibility. The most important step in the event of a bioterrorist attack is the identification of the event. This can be achieved by generating awareness, having high degree of suspicion and having a good surveillance system to assist quick detection. Bioterrorist attacks could be covert or announced and caused by virtually any pathogenic microorganism. Bioterrorist agents of major concern have been categorized as A, B and C based on the priority of the agents to pose a risk to the national security and the ease with which they can be disseminated. The five phases of activities in dealing with a bioterrorist attack are preparedness phase, early warning phase, notification phase, response phase and recovery phase. A bioterrorism attack in a public place is a public health emergency. Early detection and rapid investigation is the key to contain such attacks. The role of public health epidemiologist is critical not only in determining the scope and magnitude of the attack but also in effective implementation of interventions.

Infectious Disease Markers in Blood Donors.

BACKGROUND: The infectious disease markers for which blood donors are screened include anti-human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg), anti-hepatitis C virus (HCV), rapid plasma reagin (RPR) card test for syphilis and malarial parasites. METHODS: A total of 6751 donors were screened over three years to assess the prevalence of infectious disease markers. Screening for anti-HIV I and II, HBsAg and anti-HCV was carried out by enzyme linked immunosorbent assay (ELISA). Syphilis was tested using RPR card test. Malarial parasite was tested by detection of genus specific plasmodium lactate dehydrogenase. RESULT: The overall seropositivity for anti-HIV I and II was nine (0.13%), for HBsAg 67 (0.99%), for anti-HCV 13 (0.19%) and for syphilis 42 (0.62%). No sample showed malarial parasites. There was no significant difference (p>0.05) in the seropositivity of various markers between voluntary and replacement donors. There was a significant decline (p<0.05) in the prevalence of seropositivity for HCV and syphilis, but not for HIV and HBsAg over the three year period of the study. CONCLUSION: The prevalence of infectious disease markers was similar to that reported by other studies. However, no significant difference was seen in the marker positivity in voluntary and replacement donors, which is at variance from other studies.

Dengue: A Clinicohaematological Profile.

BACKGROUND: Fifty cases of fever, clinically suspected to be dengue were studied. METHODS: Complete clinical, haematological evaluation and IgM capture assay was done. RESULT: 54% of patients clinically suspected to have dengue were positive for IgM antibodies by enzyme-linked immunosorbent assay (ELISA). The commonest clinical feature was fever with rash (85%). Thrombocytopenia was seen in 19% of patients only. One patient died of dengue shock syndrome (DSS). CONCLUSION: Out of the 27 cases of seropositive dengue there was one death due to dengue shock syndrome. Thrombocytopenia may not always be a feature of dengue.

Molecular typing of Mycobacterium tuberculosis isolates from different parts of India based on IS6110 element polymorphism using RFLP analysis.

BACKGROUND & OBJECTIVE: IS 6110 based typing remains the internationally accepted standard and continues to provide new insights into the epidemiology of Mycobacterium tuberculosis. The aim of the study was to characterize M. tuberculosis isolates obtained from different parts of India based on IS6110 element polymorphism using restriction fragment length polymorphism (RFLP) analysis. METHODS: RFLP was analyzed among 308 isolates of M. tuberculosis deposited in the Mycobacterial Repository Centre, Agra, from different parts of India. DNAs isolated from these strains were restricted with Pvu II, transferred on to nylon membrane and hybridized with a PCR amplified DIG-labeled 245 bp IS6110 probe. RESULTS: Based on the copy number, M. tuberculosis isolates were classified into four groups, (i) lacking IS6110 element; (ii) low copy number (1-2); (iii) intermediate copy number (3-5); and (iv) high copy number (6-19). Copy number higher than 19 however was not observed in any of the isolates studied. At the national level, 56 per cent of the isolates showed high copy number of IS6110, 13 per cent showed intermediate copy number, 20 per cent showed low copy number, whereas 11 per cent isolates lacked IS6110 element. At the regional level, there was not much difference in the RFLP profiles of isolates (IS6110 copy numbers/patterns) from different parts of the country. INTERPRETATION & CONCLUSION: IS6110 DNA based fingerprinting could be a potentially useful tool for investigating the epidemiology of tuberculosis in India.

HIV AND TUBERCULOSIS CO-INFECTION IN A REFERRAL CHEST HOSPITAL.

Serving personnel of Armed Forces admitted with tuberculosis between Apr 1996-1999 were evaluated for co-infection of tuberculosis and HIV. Sixty (1.06%) of tuberculosis patients were found to be HIV positive. Initial test was done by spot kits and subsequently confirmed by ELISA on two different samples. Majority of the cases were in sexually active age group 48 (80%). Alcohol and smoking was associated in 80% cases. Thirty six (60%) were sputum smear positive for AFB. Twenty eight (46.7%) gave history of exposure to sex workers. Family members were not available for study. Sero prevalence of HIV in association with tuberculosis is less in Armed Forces compared to civil population.

A solid variant of aneurysmal bone cyst of maxilla.

A solid variant of Aneurysmal Bone cyst is very rare tumour of maxilla. Histopathologically it is very much similar to giant cell granuloma but the radiographic features can influence the pathologic interpretation.A solid variant of anenurysmal bone cyst has been reported in facial bones and it can involve several adjacent bone synchronously (3). Both giant cell granuloma and aneurysmal bone cyst have a propensity for recurrence variably in the 15%-26% range (5).

Multidrug resistant typhoid fever: study of an outbreak in Calcutta.

Of 103 cases of typhoid fever admitted to the Pediatric Wing of our hospital during the months of August 1989 to April 1990, 82.5% were resistant to chloramphenicol, ampicillin and co-trimoxozole. Nearly 87% children were in the age group of 3-10 years. Fever was present in all and splenomegaly in 90.2% cases. Urinary retention during the course of illness was present in 2 cases. The positivity rate of blood culture, bone marrow culture and Widal test was 83.7, 100 and 13.5%, respectively. Majority of the strains were of Phage 51-Type I. For the treatment of multidrug resistant cases gentamicin and furazolidine proved ineffective. Ciprofloxacin was tried in 85 cases and was found to be effective in all cases with no side effects.

Role of a large plasmid of Salmonella typhi encoding multiple drug resistance.

Twenty isolates of Salmonella typhi from cases of typhoid during the 1989-1990 epidemic in Calcutta were examined. Most isolates (84% of all isolates in the epidemic) were resistant to chloramphenicol, ampicillin, tetracycline and streptomycin but were sensitive to nalidixic acid and ciprofloxacin. Plasmids of 120 kb and 14 kb were identified amongst the multi-drug resistant isolates of S. typhi. However, there was no plasmid in the antibiotic-sensitive isolates. The 120-kb plasmid was transferable and transconjugants were resistant to chloramphenicol, ampicillin, tetracycline and streptomycin. Restriction endonuclease analysis patterns after EcoRI digestion of the 120-kb antibiotic-resistance plasmids from the S. typhi isolates and transconjugants were similar.