Epidemiological and clinical features of human rabies cases in Bali 2008-2010

Ni M Susilawathi,Gusti AK Wirasandhi,Agus E Darwinata,Nyoman S Budayanti,Ketut Subrata,Gusti NK Mahardika,Raka AA Sudewi,Ida BNP Dwija,Ni K Susilarini,Frank S Wignall

doi:10.1186/1471-2334-12-81

Abstract

BackgroundPreviously thought to be rabies free, Bali experienced an outbreak of animal and human rabies cases in November 2008. We describe the epidemiological and clinical data of human rabies cases occurring in the first two years of the outbreak.MethodsWe analysed the patient records of all rabies cases from the Sanglah General Hospital in Denpasar, and district hospitals in Buleleng and Tabanan. A conventional reverse transcriptase polymerase chain reaction was developed to detect the rabies virus genome in saliva, corneal swabs, and ante- and post-mortem cerebrospinal fluid (CSF).ResultsThere were 104 human rabies cases in Bali during November 2008-November 2010. Patients' mean age was 36.6 years (range 3-84 years; SD 20.7), most were male (56.7%), and originated from rural districts. Almost all (92%) cases had a history of dog bite. Only 5.8% had their wounds treated and received an anti-rabies vaccine (ARV) after the bite incident. No patients received rabies immunoglobulin (RIG). The estimated time from dog bite to the onset of signs and symptoms was 110.4 days (range 12-720 days; SD 118.2). The mean length of medical care until death was 21.8 hours (range 1-220 hours; SD 32.6). Less than 50% of patients had prodromal symptoms. The most frequent prodromal symptom was pain or paraesthesia at the bite site (37.6%). The two most common central nervous system infection signs were agitation (89.2%) and confusion (83.3%). Signs of autonomic nervous system dysfunction included hydrophobia (93.1%), hypersalivation (88.2%), and dyspnea (74.4%). On admission, 22 of 102 patients (21.6%) showed paralytic manifestations, while the rest (78.4%) showed furious rabies manifestations. The case-fatality rate was 100%. The rabies virus genome was detected in 50 of 101 patients (49.5%) with the highest detection rate from post-mortem CSF samples.ConclusionsRabies is a major public health problem in Bali. Human fatalities occur because of a lack of knowledge regarding rabies risk, the poor management of dog bites, and the limited availability of RIG. Increasing public awareness of dog bite management, increasing the availability of ARV and RIG, and implementing an island-wide dog vaccination campaign will help prevent human rabies cases.

Highlights

Thought to be rabies free, Bali experienced an outbreak of animal and human rabies cases in November 2008
Rabies is a fatal neuropathogenic disease caused by the rabies virus, which is an enveloped RNA virus of the Lyssavirus genus, Rhabdoviridae family [1]
Our observations indicate that among the samples taken, the best sample for Reverse transcriptase polymerase chain reaction (RT-PCR) detection is cerebrospinal fluid (CSF)

Summary

Introduction

Thought to be rabies free, Bali experienced an outbreak of animal and human rabies cases in November 2008. We describe the epidemiological and clinical data of human rabies cases occurring in the first two years of the outbreak. Bali was considered rabies free until late November 2008, but an island-wide rabies outbreak has since occurred. The number of dog bite incidents in Bali is high, with 21,806 reported in 2009 and 48,298 as of November 2010. Surveillance and recording of bite incidents was not conducted prior to 2008, because the risk of rabies was considered negligible. Rabies has been confirmed in both dogs and humans since November 2008 and 104 human cases were clinically diagnosed between November 2008 and November 2010. We will describe the epidemiological and clinical features of these human rabies cases occurring in Bali

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