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Achieving population-level immunity to rabies in free-roaming dogs in Africa and Asia.

Morters MK, McKinley TJ, Horton DL, Cleaveland S, Schoeman JP, Restif O, Whay HR, Goddard A, Fooks AR, Damriyasa IM, Wood JL - PLoS Negl Trop Dis (2014)

Bottom Line: This is the first longitudinal study to evaluate temporal variations in rabies vaccine-induced serological responses, and factors associated with these variations, at the individual level in previously unvaccinated free-roaming dog populations.This demonstrates the feasibility of achieving population-level immunity in free-roaming dog populations in rabies-endemic regions.These findings support annual mass vaccination campaigns as the most effective means to control canine rabies.

View Article: PubMed Central - PubMed

Affiliation: Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom.

ABSTRACT
Canine rabies can be effectively controlled by vaccination with readily available, high-quality vaccines. These vaccines should provide protection from challenge in healthy dogs, for the claimed period, for duration of immunity, which is often two or three years. It has been suggested that, in free-roaming dog populations where rabies is endemic, vaccine-induced protection may be compromised by immuno-suppression through malnutrition, infection and other stressors. This may reduce the proportion of dogs that seroconvert to the vaccine during vaccination campaigns and the duration of immunity of those dogs that seroconvert. Vaccination coverage may also be limited through insufficient vaccine delivery during vaccination campaigns and the loss of vaccinated individuals from populations through demographic processes. This is the first longitudinal study to evaluate temporal variations in rabies vaccine-induced serological responses, and factors associated with these variations, at the individual level in previously unvaccinated free-roaming dog populations. Individual-level serological and health-based data were collected from three cohorts of dogs in regions where rabies is endemic, one in South Africa and two in Indonesia. We found that the vast majority of dogs seroconverted to the vaccine; however, there was considerable variation in titres, partly attributable to illness and lactation at the time of vaccination. Furthermore, >70% of the dogs were vaccinated through community engagement and door-to-door vaccine delivery, even in Indonesia where the majority of the dogs needed to be caught by net on successive occasions for repeat blood sampling and vaccination. This demonstrates the feasibility of achieving population-level immunity in free-roaming dog populations in rabies-endemic regions. However, attrition of immune individuals through demographic processes and waning immunity necessitates repeat vaccination of populations within at least two years to ensure communities are protected from rabies. These findings support annual mass vaccination campaigns as the most effective means to control canine rabies.

No MeSH data available.


Related in: MedlinePlus

Declines in titre in the Zenzele research cohort.Titres of all the dogs (n = 82) in the Zenzele research cohort that were blood sampled all at four time points (30, 90, 180 and 360 days after vaccination). Upper outliers (i.e. the dogs with day 30 titres ≥128 IU/ml) are excluded. Titres in IU/ml are shown on the log scale. The geometric mean titre is shown in red.
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pntd-0003160-g001: Declines in titre in the Zenzele research cohort.Titres of all the dogs (n = 82) in the Zenzele research cohort that were blood sampled all at four time points (30, 90, 180 and 360 days after vaccination). Upper outliers (i.e. the dogs with day 30 titres ≥128 IU/ml) are excluded. Titres in IU/ml are shown on the log scale. The geometric mean titre is shown in red.

Mentions: The models take the form:where is titre and () are the covariates for observation on individual , where the final covariate () is time. Hence, time is modelled as a quadratic curve (Figure 1). The vector is a vector of regression coefficients, and the vector corresponds to a set of individual-level random effect terms, such that . Finally the error terms .


Achieving population-level immunity to rabies in free-roaming dogs in Africa and Asia.

Morters MK, McKinley TJ, Horton DL, Cleaveland S, Schoeman JP, Restif O, Whay HR, Goddard A, Fooks AR, Damriyasa IM, Wood JL - PLoS Negl Trop Dis (2014)

Declines in titre in the Zenzele research cohort.Titres of all the dogs (n = 82) in the Zenzele research cohort that were blood sampled all at four time points (30, 90, 180 and 360 days after vaccination). Upper outliers (i.e. the dogs with day 30 titres ≥128 IU/ml) are excluded. Titres in IU/ml are shown on the log scale. The geometric mean titre is shown in red.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4230884&req=5

pntd-0003160-g001: Declines in titre in the Zenzele research cohort.Titres of all the dogs (n = 82) in the Zenzele research cohort that were blood sampled all at four time points (30, 90, 180 and 360 days after vaccination). Upper outliers (i.e. the dogs with day 30 titres ≥128 IU/ml) are excluded. Titres in IU/ml are shown on the log scale. The geometric mean titre is shown in red.
Mentions: The models take the form:where is titre and () are the covariates for observation on individual , where the final covariate () is time. Hence, time is modelled as a quadratic curve (Figure 1). The vector is a vector of regression coefficients, and the vector corresponds to a set of individual-level random effect terms, such that . Finally the error terms .

Bottom Line: This is the first longitudinal study to evaluate temporal variations in rabies vaccine-induced serological responses, and factors associated with these variations, at the individual level in previously unvaccinated free-roaming dog populations.This demonstrates the feasibility of achieving population-level immunity in free-roaming dog populations in rabies-endemic regions.These findings support annual mass vaccination campaigns as the most effective means to control canine rabies.

View Article: PubMed Central - PubMed

Affiliation: Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom.

ABSTRACT
Canine rabies can be effectively controlled by vaccination with readily available, high-quality vaccines. These vaccines should provide protection from challenge in healthy dogs, for the claimed period, for duration of immunity, which is often two or three years. It has been suggested that, in free-roaming dog populations where rabies is endemic, vaccine-induced protection may be compromised by immuno-suppression through malnutrition, infection and other stressors. This may reduce the proportion of dogs that seroconvert to the vaccine during vaccination campaigns and the duration of immunity of those dogs that seroconvert. Vaccination coverage may also be limited through insufficient vaccine delivery during vaccination campaigns and the loss of vaccinated individuals from populations through demographic processes. This is the first longitudinal study to evaluate temporal variations in rabies vaccine-induced serological responses, and factors associated with these variations, at the individual level in previously unvaccinated free-roaming dog populations. Individual-level serological and health-based data were collected from three cohorts of dogs in regions where rabies is endemic, one in South Africa and two in Indonesia. We found that the vast majority of dogs seroconverted to the vaccine; however, there was considerable variation in titres, partly attributable to illness and lactation at the time of vaccination. Furthermore, >70% of the dogs were vaccinated through community engagement and door-to-door vaccine delivery, even in Indonesia where the majority of the dogs needed to be caught by net on successive occasions for repeat blood sampling and vaccination. This demonstrates the feasibility of achieving population-level immunity in free-roaming dog populations in rabies-endemic regions. However, attrition of immune individuals through demographic processes and waning immunity necessitates repeat vaccination of populations within at least two years to ensure communities are protected from rabies. These findings support annual mass vaccination campaigns as the most effective means to control canine rabies.

No MeSH data available.


Related in: MedlinePlus