Kyasanur Forest Disease Field Entomology Story.pptx

Kyasanur Forest Disease: A story about how the epidemiology of this disease unfolded and progressed due to the efforts of field epidemiologists

1. Kyasanur Forest Disease The Field Epidemiology Story Dr Ramesh J Kumar Assistant Professor Department of Community Medicine TMMC & RC, TMU

2. Kyasanur Forest Disease: The Field Epidemiology Story Unraveling the 'Monkey Fever' Mystery (1957–1970) Honoring the pioneering work of Dr. P.K. Rajagopalan

3. The Initial Puzzle: Looking for the Wrong Enemy 1957: A Disease with Unknown Etiology . Severe acute febrile illness broke out in villages near Shimoga's forests, preceded by mass monkey deaths (locally known as 'Monkey Fever’). Initial Misdiagnosis and Misdirection. The disease was initially mistaken for typhoid or feared to be the long-elusive Yellow Fever (a mosquito-borne virus).

4. Early investigations…… Panicky Reaction The Karnataka Government at that time ordered an emergency, declared a TYPHOID epidemic, patient care intensified, and free distribution of antibiotics initiated. Since Yellow Fever as a disease, transmitted by a mosquito, Aedes aegypti, was not reported in India, there was considerable excitement in both scientific and Health circles The Virus Research Centre started investigations by looking for A edes aegypti in the affected area !!! P K R

5. Mosquito studies Sh o w e d the r e w as no Ae. ae g y p ti, no di s tin c t canopy biting and ground biting mosquito Fauna. N o virus was isolated from many pools of biting mosquitoes tested. Being dry season, there were not many mosquitoes even!

6. Looking for the Wrong Enemy Before sending the workers to the field, all were vaccinated with 17-D strain of Yellow Fever vaccine, to protect the staff . As a routine procedure, pre- vaccination and second blood samples were taken from all field personnel working and tested for Virus. P K R

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8. Critical Breakpoint: Firstly, Group B viral antibodies were found in some of the blood samples. Most significantly, a strain of virus was isolated from blood samples collected from 4 insect collectors. This strain was identified as a virus belonging to Russian Spring Summer Encephalitis group . Hypothesis shifted: It must be tick-borne. P K R

9. Virus isolations were made from Febrile blood of Insect collectors of VRC, From Blood from sick monkeys,man,and from tissues of dead monkeys, even remnants of tissues from almost dried carcasses of monkeys, initially . P K R

10. P K R The mystery unfolds All the virus strains isolated were the same, belonged to RSSE group,, and was named after the forest from where the virus isolated, namely, KYASANUR FOREST adjoining Barige village, Sorab Taluk, Shimoga district, Mysore State

11. Kyasanuru and Sharavathi River Hydroelectrical Projects

12. P K R Mystery unfolds Since RSSE is a tick borne virus Immediately all mosquito studies were given up, and studies started on TICKS. This is the first comprehensive study anywhere in the world, where a group of Young scientists and workers started the investigation of A disease with unknown etiology

13. In the Pot GOI, VRC, Rockefeller Foundation, WHO, MMC

14. . Dr. Rajagopalan & the Field Lab: Targeting the Tick Pioneering Acarology. The young Dr. Rajagopalan, armed with training in Acarology (the study of ticks and mites), and his team, abandoned mosquito surveillance and mounted a massive tick collection effort . Identifying the Virus and Vector. The team successfully isolated the new virus (named Kyasanur Forest Disease Virus or KFDV) from a dead monkey in Kyasanur Forest, and from pools of ticks collected from the forest floor. The Culprit: Haemaphysalis spinigera . The vector primarily responsible for human transmission was identified as the nymphal stage of the hard tick, Haemaphysalis spinigera . Nymphs, unlike adults, feed on smaller animals, but are the stage most frequently found biting humans.

15. PKR Dissecting the first monkey found dead in the forest, and the organs harvested PK R

16. A dead monkey (Langur) being autopsied in Situ in the forest. Over 1,000 monkey deaths have been investigated and over 130 isolations of KFD virus have been made from dead monkeys. P K R

17. A flag being dragged on the forest floor to collect ticks. Tick, which are questing for prey, cling to the flag. P K R

18. Ticks ( H. papuana ) on the underside of a leaf on a bush in the forest. From such a situation they await the arrival of a suitable host to cling on to (H. R. Bhat). P K R

19. Lifespan – Upto 400 days

20. Haemaphysalis sp . The vector of KFD is an arachnid, and transmits infection to man. Picture on the left is a male, and on the right is ventral side of a female tick which shows the genital aperture on the anterior side, and the anal aperture on posterior side . P K R

21. A female Ixodid tick laying eggs P K R

22. Haemaphysalis spinigera , the tick vector of KFD. Six other species of Haemaphysalis and one species of Ixodes area also known as vectors but H. spinigera is the tick which transmits the disease to man. In the top row are the unfed and in the bottom row are the fed ticks. P K R

23. Rainfall, Vector collection and cases

24. Reservoir: S mall mammals – rats, rodents & shrews

25. Natural Hosts

26. Human Cost of Hydel Projects Dam within a Dam: Madenur Dam, also known as Hirebhaskar dam was built across river Sharavathi between 1939 and 1948. Linganamakki Dam 1964 over Sharavathi River. Full or partial submergence of 99 villages in the Sagar and 76 villages in the Hosanagar taluks of Shimoga district. Displacement of 12000 people. 

27. Human Cost of Hydel Projects Cattle play a very important role in KFD epidemiology, though the virus does not circulate to any significant levels in them. But they are the main multipliers and distributors of vector population. In the monsoon months the adult tick parasitizes cattle and the females dropped in the forest floor deposit enormous numbers of eggs, w hich remain dormant in the soil till the monsoon ends. The cattle roam about all over the forests and perhaps constitute the biggest means of tick production and DISTRIBUTION.

28. . The KFD Biocycle: The Forest's Complex Web Monkeys (Langurs & Bonnet Macaques) act as sentinels and are highly susceptible, but they are not the primary long-term reservoirs. Small Mammals (shrews, rodents) are the key amplifiers and reservoirs , maintaining the silent enzootic cycle in the forest. Cattle play a crucial role as "tick multipliers and distributors," carrying adult ticks deep into the forest where they lay millions of eggs. Seasonality: Human cases and monkey deaths peak in the dry season (Jan–May) , coinciding perfectly with the peak abundance of the questing, infected nymphal stage. Man is a Dead-End Host: There is no person-to-person or human-to-vector transmission, meaning transmission occurs solely through tick bite in the forest.

29. Human cases & monkey deaths during 1957-2004 P K R Taluk H u man Cases Monkey deaths Sorab 2761 2321 Sagar 3512 319 Hosnagar 3683 592 Thirthahalli 6786 399 Sirsi 239 64 N.R. Pura 1050 58 Koppa 772 68 Belthangdi 1092 324 Other areas 4826 2330 Total 24721 6475

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31. Boshell’s Cup of Coffee: Ecology & Outbreaks The disease requires a combination of many factors, all occurring in adequate quantities and of appropriate quality at a given time. The Ingredients: KFD virus (quality coffee seeds), Vector population (thick decoction), Susceptible monkeys (fresh cream), and Susceptible humans (freshly roasted). The Optimum Season: The "Right proportion" (Optimum season) when all ingredients align for a human case. Human Impact: Ecological disturbance, such as the Sharavathy Dam project and deforestation, created extensive "interfaces" between forest and open land, increasing opportunities for transmission.