Rabies in the Dutch East Indies a centaury ago – a case study in disease emergence

1. Rabies in the Dutch East Indies a centaury ago – a case study in disease emergence MICHAEL WARD | Chair, Veterinary Public Health & Food Safety

2. Outline history of rabies in Indonesia and the current situation lessons in history: field data and observations re-constructing the past: spatial and temporal analyses what have we learnt?

3. rabies [Latin] "madness" • rabhas [Sanskrit] "to do violence" • lud [Greek] "violent" … lyssa • first written record of rabies: Mesopotamian Codex of Eshnunna (circa 1930 BC) • owner of a dog showing symptoms of rabies should take preventive measure against bites • if another person were bitten by a rabid dog and later died, the owner was heavily fined

4. The history of rabies • remained a continual threat in Europe and the Middle East during the Middle Ages • entered Africa and the Americas with colonisation? • early records from China (556 B.C.), Japan (1600s) • status in Southeast Asia pre-colonisation? A woodcut from the Middle Ages showing a rabid dog

6. First report of rabies in Indonesia Esser, W.J. Diagnose "Dolheid" bijeenBuffel [Diagnosis of Rabies in a Buffalo]. VeerartsenjikundigebladenvoorNederlandsch-Indie 1889;3:102-104.

7. Rabies spread and distribution  Indonesia In Nederlandsch-IIndie is in 95% dergevallen de hond de oorzaakderinfectie; de overige 5% wordengeleverd door katten, apen, paarden, runderen, en bijzeerhoogeuitzonderingaanlyssalijdendemenschen. Rabies bijhonden is bekend op de 4 grooteSoenda-eilanden, en ook op eengrootaantalkleinereeilanden van den arcipel. Sommigeeilandeenzijnnognietgeinfecteerd, maar de toeneming van het verkeer, gepaard van honden, katten en apenzullen op den duurnietnalaten de infectietehelpenoverbrengennaar die plaatsen. In the Dutch Indies in 95% of cases the dog is the cause of infection with the remaining 5% caused by cats, monkeys, horses, cattle, and very exceptionally people suffering from hydrophobia. Rabies in dogs is known on the 4 Greater Sunda Islands, and also many smaller islands of the archipelago. Some islands are not yet infected, but the increase in traffic, accompanied by dogs, cats and monkeys over time will not fail to help transmit the infection to those places.

8. Rabies spread and distribution  Indonesia Courtesy Agung Putra

9. Ongoing rabies spread  Maluku Islands Newly infected areas 2003 Ambon 2006 Seram, Buru Central Halmahera 2010 Larat, Yamdena 2012 Babar, Kisar

10. Why is rabies still spreading? Courtesy Helen Scott-Orr • Indonesia’s large population and enormous cultural diversity • decentralised government • 33 provinces & 444 districts • increased prosperity and inter-island trade • long incubation period in dogs (1 wk  >6 mth) • delayed detection • dogs on fishing boats • movement of pets • commercial trade in dogs • enforcement of intra-island movement control

11. Lessons in history: field data and observations

12. Lessons in history: field data and observations

13. Lessons in history: field data and observations

14. Lessons in history: field data and observations

15. Lessons in history: field data and observations

16. Lessons in history: field data and observations

17. Lessons in history: field data and observations

19. Lessons in history: data analysis reports  administrative units of Indonesia proportional symbol maps, semivariography, kriging: year of first report mean centre, directional ellipses global clustering: Moran’s I, nearest neighbourtest, K-function local clusters: scan statistic time series of human cases and livestock cases autoregressive, autoregressive integrated moving average (ARIMA) models multivariate autoregression models

20. Rabies statistics, 1897‒1916 • 8,826 reported human cases; 218 (1898)  907 (1915) • less common September (667)  December (800) • wet versus dry seasons, 50.8 versus 49.2% • mortality (untreated) >35%, (treated) 1.5%; • higher outside Java (3.1% vs 1.3%), locals (2.1% vs 0.2%)

21. Rabies statistics, 1897‒1916 • 1,033 reported livestock cases; 8 (1908)  235(1916) • less common March/July (75)  December (108) • wet versus dry seasons, 38.3 versus 61.7%

22. Rabies cases, 1897‒1916 Reported human case numbers

23. Rabies cases, 1897‒1916 The mean centres and directional deviational ellipses (unweighted and weighted [bold star] by numbers of reports) of the origin of human cases treated for rabies exposure in the Dutch East Indies during the period 1897 to 1916.

24. Rabies cases, 1897‒1916 Year of first report, human cases

25. Rabies cases, 1897‒1916 Interpolation of the year of first report by district of origin of human cases treated for rabies exposure in the Dutch East Indies during the period 1897 to 1916. Data were interpolated using a Gaussian function with estimated nugget, partial still and range of 0.04, 40.0 and 860 km, respectively. Darker shading indicates earlier reporting during this period.

26. Rabies cases, 1897‒1916 Clusters of human cases treated for rabies exposure in the Dutch East Indies during the period 1897 to 1917, identified using permutation (scan statistic) tests. The most likely cluster (focused on the west coast of Sumatra and occurring between 1899 and 1905) is shown in bold.

27. Rabies cases, 1897‒1916 Reported human cases

28. Rabies cases, 1908‒1916 Monthly reports of human cases treated for rabies exposure and livestock cases of rabies in the Dutch East Indies, January 1908 to December 1916. The correlation between these two time series was 64.2%.

29. Time series analysis • human time-series (1903 to 1916): • significant linear increase (0.1632 cases per year) • significant positive autocorrelations at months 17 • significant partial autocorrelations at months 1–3 for human cases • livestock time-series (1908 to 1916): • NS (P = 0.053) linear increase (0.0496 cases per year) • significant positive autocorrelations at months 1–6 • significant partial autocorrelations at months 1 and 2

30. Time series analysis human cases beta P-value t-1 0.3576 <0.001 t-2 0.1659 0.040 t-3 0.1871 0.015 (AICc 6.22140) livestock cases betaP-value t-1 0.2716 0.011 t-2 0.23340.030 t-3 0.20970.048 (AICc4.40229)

31. Time series analysis ARIMA [p,d,q x P,D,Q, season] models: human cases (1,1,1) x (2,1,2) x2 livestock cases (2,1,1) x (1,1,2) x3 human cases beta P-value livestock cases t-0 1.4035 <0.001 t-1 0.7544 0.005

32. What have we learnt? • 1897–1916: rabies spread throughout much of the archipelago • Java and West Sumatra  Sulawesi, Borneo, other islands • mostly likely spatio-temporal cluster: west coast of Sumatra, 1899-1905 • one of the first major spread events in the Dutch Indies? • central Java (1898–1899) • early epidemic phase? • east coast of Sumatra (1903–1906), east Java (1910–1911), Makassar, Sulawesi and eastern Indonesia (1912), Borneo (1914) • independent spread events?

33. What have we learnt? • spread of rabies via the movement of dogs • military forces • trade • pets • Some islands are not yet infected, but the increase in traffic, accompanied by dogs, cats and monkeys over time will not fail to help transmit the infection to those places. Winckel, 1918 • Due to the numerous transfers of people, especially soldiers, from Java to the Outer Territories were these lands by the entrained dogs gradually infected ...". t’ Hoen, 1913

34. What have we learnt? “In August–September 1899 five traders travelled to a locality in the north of the island of Sumatra to buy dogs. The market-goers there warned the traders that the dogs in the area were behaving strangely, however a sale was concluded (at an extraordinary low price). On the return journey the dog bit all 5 traders and escaped. All 5 traders died within 3 months. It was reported that the dog continued in the area to bite a large number of pigs, dogs, cattle and buffalo, of which the majority succumbed to rabies. Amongst dogs alone, there were claimed to be more than 200 cases.”

35. Rabies Risk Assessment Understand the pathways of the easterly and southerly spread of rabies through eastern Indonesia and prioritise these pathways for surveillance

44. Rabies in the Dutch East Indies a centaury ago archipelago status no barrier to rabies spread regulations to control rabies have existed for >100 years further emergence of rabies likely to occur based on an island’s position with complex network targeted surveillance and enforcement of quarantine regulations remain critical

45. Acknowledgements

46. Rabies in the Dutch East Indies a centaury ago – a case study in disease emergence MICHAEL WARD | Chair, Veterinary Public Health & Food Safety

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