A 100 Years of Rabies in Kenya A Rabies-FREE Kenya by 2030 Thumbi Mwangi 1,2, Bitek A 3, Nanyingi M 4, Rees Muriithi 3, PM Kitala 4, MK Njenga 1, 2 et al 1 Paul G. Allen School for Global Animal Health, Washington State University 2 Center for Global Health Research, Kenya Medical Research Institute 3 Directorate of Veterinary Services, MOALF, Kenya 4 Department of Public Health, Pharmacology and Toxicology, University of Nairobi, Kenya 50th Annual Scientific Conference, Three Steers Meru, 27th 30TH April 2016 Rabies-free Kenya 1 / 27
talk outline 1 The 100-Year History of Rabies in Kenya 2 How and Why we can and will Kick Rabies out of Kenya
ancient rabies Evidence of rabies in Kenya during the pre-colonial times Inhabitants of South Nyanza referred to the disease in dogs and jackals as Swao 1 Hudson JR (1944) A short history of rabies in Kenya EA Med J 21:322-327
period 1900-1912 Official Veterinary reports (1909, 1912) show rabies was not diagnosed in Kenya from 1900-1912 3 First record of a confirmed rabies case in 1912 In a dog attacked and bitten by a jackal Location: Nairobi Confirmation: Negri bodies in its brain and through experimental inoculation Image from the Colonel Robert John Stordy, Chief Veterinary Officer 1910. 2 Similar cases followed rapidly in Nairobi and Kiambu Anon (1909, 1912) Annual Report. Veterinary Department Ministry of Agriculture, Kenya
Spatial spread: period 1912-1920 Outbreak lasted until 1916 Cases confined to Nairobi and Kiambu areas 4 At Fort Smith, Nairobi (1913-1914) and At Kabete (1916) Diagnostics: rabbits inoculated with material from the infected animals No record of human rabies case yet! Kariuki D.P and Ngulo W.K (1983) Epidemiology of Animal Rabies in Kenya (1900-1983) in book E. Kuwert et al Rabies in the Tropics, Springer-Verlag
Spatial spread: period 1921-1950 First human case 1928 - a woman in South Nyanza - died a month after dog bite Disease in dogs spreads to Laikipia and Wajir (1928), Wajir and Mandera in Jackals (1929)
Spatial spread: period 1921-1950 Outbreak in 1931 -started in Kisumu and South Nyanza spread north-east, by 1950 all districts in Western Kenya had experienced rabies Up to 1950 - except for a few isolated cases in Wajir, Mandela, Laikipia and Kitui - most cases were in Western Kenya/West of Rift Valley Disease Control <1950: Vaccine from Pasteur Institute Algiers, and destruction of stray dogs
Spatial spread: period 1951-1980 1951-60: Disease persists in Western Kenya, and new outbreaks occur east of the Rift Valley, in Central Province (1957), further spreading to Isiolo and Kitui districts (1957-59) 1951-60: First use of locally produced vaccine - passaged through embryonated eggs
Spatial spread: period 1951-1980 1953: Adoption of a policy on compulsory annual vaccinations (ear tattooing for vaccinated dogs), baiting and shooting of strays after vaccinations, house to house searches and owners of unvaccinated dogs prosecuted and dogs vaccinated By 1974 - rabies was virtually eliminated in Kenya - except for isolated cases in a few districts and a persistent foci of infection in Machakos and Kitui where a sylvatic cycle of rabies disease was postulated.
Temporal pattern of rabies cases: period 1958-2015 End of 1974 - outbreak in Taveta, spread to the coastal strip including Mombasa Island by 1979. 1979 - a major in incursion in Trans Mara close to Tanzania border - spread northwards to South Nyanza. Same year - yet another outbreak beginning in Bungoma district - near Uganda border.
Spatial spread: period 1971-2000 Early 80 s: Economic, social and political changes drastically affected disease control programmes negatively, including in neighbouring countries. Additionally, implementation of the Structural Adjustment Policies that converted veterinary services from a public good to the private sector.
Spatial spread: period 2000-2015 To-date rabies is endemic in all counties in Kenya The magnitude of the disease is masked by the poor surveillance system for rabies disease
Samples submitted and results (1958-2015) Species No. samples submitted Number positive % positive Domestic Canine 4,466 2,265 50.7 Feline 470 154 32.8 Bovine 1,401 981 70 Ovine/Caprine 352 244 69.3 Equine 164 111 67.7 Porcine 11 6 54.5 Sub-total 6,919 3,771 54.5 Wildlife Canine 135 54 40 Mongoose 60 38 63.3 Honey Badger 39 23 59 Feline 9 4 44.4 Others 152 12 7.9 Sub-total 395 157 39.7 Human 164 114 69.5 TOTAL 7,478 4,042 54.1
Rabies burden by county Machakos, Makueni and Nairobi cumulatively had the highest burden ***These data only as good as the surveillance/sample submission
Temporal pattern by animals affected: period 1958-2015 Pattern of human cases follow those of domestic animals Following the large outbreak in the 80 s, rabies cases have remained higher than observed in the 70 s.
Temporal pattern by animals affected: period 1958-2015 Most rabies cases recorded have been in dogs - followed by cattle Wildlife cases have been reported - but these have remained low in numbers
What new things have we learnt about Rabies Disease and its Control/elimination? 1953: Adoption of a policy on compulsory annual vaccinations (ear tattooing for vaccinated dogs), baiting and shooting of strays after vaccinations, house to house searches and owners of unvaccinated dogs prosecuted and dogs vaccinated
a) Compulsory annual vaccinations for all dogs? R 0 =2 No. of secondary cases from infected individual in a susceptible population 2 secondary infec.ons 2 0 0 Vaccinated animals What proportion of the susceptible dog population should be vaccinated to achieve elimination? 1 1 70% of the dog population Vaccination can break the cycle of transmission Three consecutive years
The good news is R 0 for rabies is VERY low ~1.1-1.3 On average each rabid dog infects 1.2 others Low value of R 0 suggests that elimination should be feasible 5 5 Hampson et al 2009 PLoS Biol 7:e53
R 0 for rabies is lower than for other diseases that have been eliminated and eradicated Smallpox R 0 = 3-5 Polio R 0 = 5-7 Rinderpest R 0 = ~5 Measles R 0 = 10-15 Based on Rabies R0 - critical vaccination threshold between 20-40% Rabies R 0 =1-2 P crit =1- (1/R 0 ) High dog turn-over (births and deaths) - increase threshold to 70%
b) Baiting and shooting of strays? Destruction of stray dogs is NOT an effective strategy! Majority of stray dogs are owned a, b Dog density does not strongly influence rabies transmission c Dog ecology is mediated by humans Easy to cull dogs are the easy to vaccinate a Gsell et al, 2013 b Kaare et al 2009 c Hampson et al 2009 PLoS Biol 7:e53
Strategy for the Elimination of Human-Rabies in Kenya 1 Mass dog vaccinations (70% coverage for 3 years consecutively) 2 Provision of PreP and PEP for bite victims 3 Public education and awareness on rabies prevention and control 4 Enhanced surveillance for rabies cases in animals and humans
Zone A: Pilot districts: Western Kenya - (Kisumu, Siaya) Eastern Kenya (Machakos, Makueni, Kitui) Zone B close proximity to pilot areas Rest of the country
Where are we at? Timelines Stages in the Rabies progressive control pathway 2030 - STAGE 5 -Maintain freedom-from-rabies status in humans and dogs 2028-2029 STAGE 4 -Maintain freedom from dog-mediated human rabies - Elimination of dog rabies 2017-2027 STAGE 3 Rabies risk reduction through full-scale implementation of the control strategy 2014-2019 STAGE 2 - Implementation of the National Rabies control strategy in pilot districts 2013-2014 STAGE 1 - Development and adoption of the National Rabies control strategy - Preparation for its implementation - 2013 STAGE 0 - Rabies suspected to be present - Scanty information available
Where are we at? Kenya at Stage 1: National Rabies Control Strategy developed and adopted in 2014 Makueni in Stage 2: Implementation of the Strategy in the pilot counties (working with World Animal Protection) Dog census (estimated 120,000 dogs) Mass dog vaccinations Rabies education and awareness campaigns
Where are we at (funding)? Zoonotic Disease unit in advanced talks with Sanofi Pasteur to start enhanced surveillance for rabies in humans in Makueni Health-facility surveillance for animal bites (creation of Animal Bite Centers) Contact-tracing/case-finding in the communities Toll-free numbers to enhance reporting of animal bites and adherence to PEP Wellcome Trust 3-year funding for Rabies Elimination Implementation Research EU parliament funding to the DVS through the OIE for implementation of Stage 1 and 2 of the Rabies Elimination Strategy (Siaya and Makueni Counties) Sustainable funding for rabies elimination implementation will likely remain from within (County funds, private sector companies and philanthropists)
TOWARDS A RABIES-FREE KENYA Vaccinate your dog, Save lives!