Vaccinating Dogs to Reduce Occurrence of Rabies

Rabies is a deadly wildlife disease that has to be treated immediately for a host to have a chance at survival. Due to this urgent nature of the disease, it is one that health organizations want to eradicate as soon as possible. As a zoonotic disease, it affects both humans and other mammals such as dogs, raccoons, bats, and skunks. Therefore, if the disease is to be pushed towards extinction, then its prevalence in the wild also has to be reduced.

India has over 20,000 deaths per year due to rabies each year, which is over 35% of the total deaths caused by rabies in the world. These numbers indicate that it is a pressing matter that has to be dealt with immediately. The study performed by Gibson et al. uses a novel method to vaccinate dogs and reduce the transmission of the disease to humans, and also to decrease its occurrence in the canine population. Since the leading cause for rabies in humans is via dogs, the number of deaths and infections that occur will decline as a direct result of the vaccinations. Although rabies is a current issue, there have not been any large scale studies or programs that have been successful at vaccinating the dogs in India. If successful, then this study will provide a method to tackle the problem and perhaps even develop herd immunity in the future.

In order for the vaccination to be effective, at least 70% of the dog population has to be vaccinated. Previous studies have shown that this is the percentage needed to effectively reduce transmission to humans. It will break the transmission link in the chain of infection and reduce the incidence of rabies in the population. The researchers chose the city of Ranchi to perform the study. The city is split into 55 administrative sections called ‘wards’.

ronchi map

Teams of researchers went out into the wards and performed one of two actions: a catch-neuter-vaccinate-release (CNVR) process or a vaccinate-mark-release (VMR) process. They used a ‘Mission Rabies’ App on a smart phone to record various pieces of information that was then uploaded to a server. Information such as GPS location, ward number, action taken on the dog, sex, ownership status, age, neuter status, body condition, and the presence or lack of alopecia were gathered and recorded. This collection of data not only allows the researchers to keep accurate track of the dogs vaccinated, but also provides a database of information that can later be used for further studies relating to the dog population. Once vaccinated, the dogs were marked with a non-toxic paint on their back for identification and also to prevent repeat vaccination. Researchers traveled out to each ward after vaccination to conduct post-vaccination surveys. They observed free roaming dogs looking for the marked backs and also recorded data similar to that collected during vaccination. If more than 70% of the dogs sighted were marked then the ward is considered to be vaccinated successful. If not then researchers go out again to the ward and vaccinate more dogs until the post-vaccination survey reaches 70%.

vaccine 1

vaccine 2

Highlighted rows are wards with less than 70% dogs vaccinated.

The data presented in this research is for 18 wards only, while vaccination was ongoing in 21 other wards. Table 1 shows that fourteen of the eighteen wards had at least 70% of the dogs vaccinate after the first round of vaccination. Researchers returned to four wards for a second time and vaccinated an additional 311 dogs. Two of the wards reached the goal while the other two had 68.2% and 66.7% vaccination dogs. This can be seen in Table 2. Significantly, the lowest confident interval was greater than 70% in three-fourths of the wards.

vaccine map

Figure above illustrates the wards where dogs have received vaccinations. The overwhelming presence of green colored wards indicates that this method can be successful on a large scale.

This study marked the first time a mobile app was used for vaccination and data collection. It proved to be very efficient as it allowed for faster data collection and it was uploaded to a centralized location automatically where it could be used for multiple purposes. By targeting smaller areas, the wards, research teams were able to successfully vaccinate at least 70% of the dogs in all but 2 wards. If this concentrated vaccination can be carried out systematically, then the target number of dogs can be vaccinated within a city and eventually within a state. This should be the long term goal. Although this can solve the rabies problem, the researchers do mention that it does not solve the abundance of street dogs. They predict that if the captured dogs are also neutered then it can reduce mating and production of offsprings. However, this is not a very cost effective method considering the large number of dogs present in India and the resources required for such a venture.

The idea to incorporate mobile apps into a vaccination exercise is modern. It makes perfect sense to take full advantage of the technology available to solve a problem that has been present for years. The paper did not address how the researchers accounted for dog movement. The dogs present in one ward during vaccination are not guaranteed to be in the same ward during post-vaccination survey. They could travel to nearby wards and increase or decrease the percentage of a ward. Even if this was a factor, the percent of dogs vaccinate is still a high number. The results from the 21 wards where vaccination is ongoing should be analyzed and the next steps of expanding the area should be taken.

 

Work cited:
Gibson AD, Ohal P, Shervell K, Handel IG, Bronsvoort BM, Mellanny RJ, Gamble L. 2015. Vaccinate-assess-move method of mass canine rabies vaccination utilising mobile technology data collection in Ranchi, India. BMC Infectious Diseases. [Internet]. Retrieved from: http://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-015-1320-2

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