Abstract
Rabies is one of the notifiable zoonoses in Sri Lanka. 96% of human rabies deaths occur due to dog bites. The dog is the main reservoir and the transmitter of the disease in the community.In Sri Lanka, vaccination as a prophylactic measure to control canine rabies was practiced only for domestic dogs till 2006. Elimination was the main control measure for stray dogs during this period. The new strategy of mass parenteral vaccination of stray dogs in addition to the domestic dogs, instead of stray dog elimination, has been implemented by the health authorities of Sri Lanka after 2007. Apart from that, chemical and surgical birth control methods also were introduced to control the stray dog population density since 2007. An Autoplunger, a newly invented instrument in Sri lanka was utilized for intramuscular vaccination of stray dogs. The main objective of this study was to find out the effectiveness of mass vaccination of stray dogs against rabies as a prophylactic measure to reduce the incidence of human rabies deaths due to stray dogs in Sri Lanka. The data obtained from quarterly bulletins of the department of epidemiology and the department of the public health and veterinary services of the ministry of health between 2007 and 2010 were analyzed. The data revealed the incidence of human deaths due to stray dog bites has increased from 16 in 2001 to 28 in 2006 whereas the incidence has decreased from 21 in 2007 to 18 in 2010.The total number of female stray dogs subjected to chemical birth control were 90380,85339,53931 and 39888 in 2007, 2008, 2009 and 2010 respectively. Total number of female stray dogs surgically sterilized were 1848, 119546, 220280 and 90764 for these corresponding years. It has been reported that Some provinces have not carred out proper vaccination and population control measures on stray dogs due to various issues in 2010 compaired to 2009. The statistical analysis revealed a weak negative correlation (r= 0.27, R²=0.072) between the mass vaccination of stray dogs against Rabies and the incidence of human rabies deaths due to stray dog bites. However, the mass vaccination of stray dogs against rabies helps to establish herd immunity in stray dog reservoir and its feedback effect helps to arrest the transmission chain of virus among stray dogs. Therefore in conclusion, mass vaccination of stray dogs makes the public less susceptible for rabies due to stray dogs. Further strengthening of annual mass vaccination of stray dogs and population control measures to a greater extent in a methodical way at provincial level in future is recommended.
