Rabies in the Dutch East Indies a century ago - a spatio-temporal case study in disease emergence.

Rabies continues to spread through the Indonesian archipelago. During the past 20 years, several islands - including Flores, Ambon and Bali - that had historically been free of rabies have become infected. However, the Dutch East Indies (a Dutch colony that became modern Indonesia following World War II) had been infected since the 1880s. The spread of rabies is a lesson in the emergence of an infectious disease. Reports of human cases treated for rabies and livestock rabies cases from the 1880s to 1917 were compiled. The spatial and temporal distribution of these cases was analyzed using maps, spatial statistics and time-series techniques. The first confirmed case of rabies was reported in 1889 from the Batavia [Jakarta] district (although disease suspicion was reported as early as 1884). During the 1890s rabies was already commonly reported from Java and the east coast of Sumatra, and by the late 1890s, from Celebes [Sulawesi]. Between 1900 and 1916, cases were reported from other parts of Java, Sumatra and Sulawesi, and from Borneo, the Moluccas and other outlying islands. Between 1897 and 1916, a total of 8826 human cases treated for rabies were reported and between 1908 and 1917, 1033 livestock cases were reported. Most (97.5%) human cases treated were attributed to rabid dogs. Increasing numbers of reports were observed during the period. Between 1908 and 1916 the correlation between human and livestock case reports was 64.2%, and at the district level it was 75.9%. Moderate correlations (>40%) were found between human cases and livestock cases reported up to six months previously. Based on year of first report from each district, human cases were strongly clustered (Moran's autocorrelation 0.47, P=0.005). The most likely spatio-temporal cluster of reported cases of humans treated for rabies originated from the west coast of Sumatra between 1899 and 1905, and other clusters were identified in west Java (1898-1899), the district of Batavia and in east Java (1910-1911), Nusa Tengarra Barat (1912), Borneo (1914) and the east coast of Sumatra (1903-1906). Rabies was probably first introduced to the colonial capital of the Dutch Indies, Batavia [Jakarta] in the 1880s. It then spread rapidly throughout most of the archipelago during the next two to three decades because of the movement of dogs via the military forces, for trade and as pets, despite government regulations designed to control the epidemic. Such a history suggests that further emergence and reemergence of rabies in rabies-free islands will occur based on an island's location and position within the complex social, trade and transport network that represents the Indonesian archipelago. Targeted surveillance and enforcement of quarantine regulations remain critical, to prevent history repeating itself.