OBJECTIVE

Given that rabies remains endemic in the Philippines despite government interventions and the pandemicrelated restrictions have hampered its surveillance, this study aimed to estimate the effect of human population, anti-rabies vaccination efforts, and COVID-19 situation on the spread of rabies cases in the districts of Davao City, Philippines.

METHODS

A retrospective study of the canine records at Davao City Veterinarians’ Office was done from January 2018 to June 2021. Monthly rabies cases were ascertained, and the effect of the human population, COVID-19 season, and vaccination ratio on rabies cases was estimated using panel regression models adjusting for confounding factors.

RESULTS

The reporting of rabies cases was lower during COVID-19 than during the non-COVID-19 season, with an IRR of 0.52 [95% confidence interval (CI): 0.33–0.82]. Furthermore, rabies cases increased by 2.23% (95% CI: 0.60–3.89) per 1% increase in vaccination ratio. Additionally, high-population districts recorded more rabies cases than low-population districts.

CONCLUSION

Consistency in monitoring rabies cases during the pandemic is suggested as a roadmap for future program initiatives. Vaccination efforts should be reinforced to increase rabies awareness and ensure early response to emerging diseases. Moreover, highpopulated districts should be prioritized in implementing rabies control interventions to gain optimal development.

Human ; Animals ; Rabies ; Covid-19 ; Vaccination

BACKGROUND AND OBJECTIVE

Rabies continues to be a challenge in Davao City despite the efforts of the city’s local government to vaccinate primarily the non-stray dog population. Meanwhile, studies have shown that time-dependent vaccination strategy is considered a prime factor for a cost-effective rabies control strategy. Hence, this study aims to provide information that will determine the optimal vaccination strategy targeted to the stray dog population that minimizes the rabies-infected dog population and vaccination costs using optimal control theory (OCT).

METHODS

OCT is used to identify the optimal level of key rabies control, i.e., vaccination. Here, OCT was applied to a modified Susceptible-Exposed-Infectious-Vaccinated (SEIV) compartmental model. The study's key parameters were derived from published articles on rabies in Davao City and similar regions, along with the city's rabies reports.

RESULTS

The findings revealed that while rabies remains endemic in the city, it is possible to reduce the number of cases through consistent implementation of vaccination programs to the exposed and susceptible dog populations. Nevertheless, the feasibility of these findings relies to the effective targeting of vaccine coverage for the dog population. From the simulations performed, the exposed dog population (i.e., pre-rabid dogs) was able to reach zero observation when the transmission rate (?) is 0.001 for all values of anti-rabies vaccine coverages for exposed (?) and susceptible (b) dog populations and ? = 0.01 only when ? = 0.7 and b = 0.7, ? = 0.7 and b = 0.5, and ? = 0.5 and b = 0.7. Consequently, the number of infectious dogs will thereby decrease. Moreover, a nonlinear correspondence was also observed in all scenarios between the vaccination rate and the number of rabies-exposed dogs such that the reduction in the incidence of rabies cases becomes apparent only when the vaccination rate is at least 0.9995.

CONCLUSION

In high rabies transmissibility scenarios, a time-dependent vaccination strategy demonstrated a reduction in the number of rabies-infected dogs. However, this approach involves a trade-off, limiting the period during which monthly vaccinations can be relaxed. Consequently, a robust and timely vaccination program for dogs is crucial to manage high rabies transmission rates. Lastly, the model simulation underscores the importance of initiating monthly vaccinations.

Animals ; Rabies