Factors of rabies maintenance in dog population in Kinshasa, Democratic Republic of Congo (DRC)

Abstract

Purpose: Rabies kills every year 61 000 humans in the world, mainly in Asia and Africa. In the Democratic Republic of Congo (DRC), rabies is endemic and the dog is the main vector of human rabies. From 1937 to 2017, around 1400 positive dog rabies cases were recorded across the country. The study aims to better understand the epidemiological factors of rabies maintenance in dogs in Kinshasa. Methods & Materials: We conducted 4 studies. (i) A household survey in 22 study sites in 3 municipalities of Kinshasa suburb (Mont-Ngafula, Ngaliema and Lemba). It provided information about the dog density, roaming and vaccination coverage. Based on these factors, a risk scale of rabies transmission was established. (ii) Owned dogs (n = 16) were tracked during 24 hours using GPS collars. The probability of contact with other dogs was calculated. (iii) The proportion of feral dogs was estimated by the street count method. (iv) Finally, the serological status of dogs that were reported vaccinated was checked. Generalized linear models were used for statistical analysis. Results: We recorded 922 dogs in 504 surveyed households. 60% (2–100%) of these dogs were free roaming. Feral dogs were estimated to be less than 2% of the free roaming dogs. Dog density was estimated to be 47 dogs/km2. The mean distance covered by tracked dogs was 0.718 km (0.046–2.341 km) per day and each dog had a chance to come in contact with 27 free roaming dogs. The vaccination coverage was 53% (24–81%). 91% of the dogs that were reported vaccinated (n = 131) were seropositive, confirming owners’ reports. The proportion of protected dogs (serology ≥0.5 IU/ml) was not associated with the time since the last vaccination (p = 0.4). In DRC, vaccination of dogs is exclusively funded by owners. This may explain why the coverage is low in young (≤1 year old) and free roaming dogs. The estimated risk of rabies transmission ranged from moderate to high in 80% of study sites (n = 22). Conclusion: The risk of rabies transmission is high in the study area, given the high proportion of unvaccinated free roaming dogs and low vaccination coverage (<70%) mainly in young dogs. ARES-CUD funded this research.