Prompt laboratory diagnosis in timely containment of a plague outbreak in India.

A focal outbreak of pneumonic plague occurred in a hamlet of village Hatkoti, district Shimla, Himachal Pradesh in the first fortnight of February, 2002. A total of 16 cases with 4 deaths were reported. Diagnosis of plague was confirmed by the laboratory in 10 (63%) cases. Y. pestis was isolated from clinical samples of 3 cases and confirmed by bacteriophage lysis. Molecular tests confirmed the presence of Y. pestis specific pla and F1 genes in 4 cases; DNA fingerprinting had identity with the known sequence of plague bacilli. Paired samples from 5 cases showed more than 4 fold rise and 1 case showed more than 4 fold fall in antibodies against F1 antigen of Y. pestis. The present communication emphasises that timely and systematic laboratory investigations give confirmatory diagnosis in shortest possible time which forms the backbone of the outbreak control in a timely fashion and prevents confusion and controversy.

Nipah/Hendra virus outbreak in Siliguri, West Bengal, India in 2001.

BACKGROUND & OBJECTIVE: The viral encephalitides caused by animal or human viruses are characterized by sudden outbreaks of neurological disease in both tropical and temperate regions. An outbreak of acute encephalitis occurred in Siliguri (West Bengal) town of India between January 31 and February 23, 2001. This outbreak was investigated by a team of scientists from four major institutions, and the findings are presented here. METHODS: Detailed information about the outbreak was collected with the help of local health authorities. Limited entomological investigations were also done. Samples collected from cases and contacts were sent for analysis. RESULTS: A total of 66 probable cases and 45 deaths were reported. Epidemiological linkages between cases point towards person-to-person transmission and incubation period of around 10 days. There was neither any concurrent illness in animals nor was there any exposure of cases to animals. Centres for Disease Control and Prevention, Atlanta, USA concluded on the basis of tests carried out on serum specimen from four cases and two contacts that the causative pathogen appears to be Nipah/ Hendra or closely related virus. INTERPRETATION & CONCLUSION: This outbreak highlights the importance and urgency of establishing a strong surveillance system supported by a network of state-of-the-art laboratories equipped to handle and diagnose new pathogens and including patient isolation techniques, use of personal protective equipment, barrier nursing and safe disposal of potentially infected material in the prevention and control measures for Nipah/Hendra virus infection.

Epidemiological characteristics of rabies in Delhi and surrounding areas, 1998.

OBJECTIVE: To describe the epidemiological characteristics of rabies in Delhi in 1998. METHODS: Analysis of the records of hydrophobia cases admitted to the Infectious Diseases Hospital, Delhi (IDH) in 1998. RESULTS: About 46 percent (99/215) of the hydrophobia cases admitted to the IDH in 1998 belonged to Delhi. The remaining came from the adjoining states, both urban and rural areas. In Delhi residents, overall hospitalization rate was 0.81 per 100,000 population. It was significantly higher in 5-14 year old than in other age groups and in males than in females (p <0.0009). Cases occurred round the year. Almost 96 percent cases (206/215) gave history of animal exposure, 13 days to 10 years (median 60 days) before hospitalization. Majority (195/206) had class III exposure. Animals involved were stray dog (193/206 = 90 percent), pet dog, cat, jackal, mongoose, monkey and fox. Most of cases were never vaccinated (78 percent) or inadequately vaccinated (22 percent); only 1 percent each received appropriate wound treatment, or rabies immunoglobulin. CONCLUSIONS: Rabies is a major public health problem in Delhi. Its incidence is significantly higher in 5-14 year old children than in other age groups. The results indicate the need to educate the community and health care workers about the importance of immediate and adequate post-exposure treatment and to start an effective control program for dogs, the principal vector of rabies.