Défense de thèse de doctorat en médecine vétérinaire

Canine rabies in Kinshasa, Democratic Republic of the Congo: assessment of maintenance factors transmission and modelling control vaccination schemes

Jury

• Nicolas GILLER (UNamur), President
• Nathalie KIRSCHVINK (UNamur), Supervisor and Secretary
• Tanguy MARCOTTY (UNamur)
• Benoît MUYLKENS (UNamur)
• Claire DIEDERICH (UNamur)
• Catherine LINARD (UNamur)
• Nicolas ANTOINE-MOUSSIAUX (ULiège)
• Jean-Paul DEHOUX (UCLouvain)
• Severine THYS (UGent)
  

Abstract

Rabies causes every year death of 61,000 humans in the world, mainly in Asia and Africa. In Democratic Republic of the Congo (DRC), from 1923 to nowadays, small and large rabies outbreaks are still reported. Despite the fact that the elimination of rabies is feasible, the disease remains endemic in dogs which are the main vector of human rabies in DRC. Accordingly, this thesis aimed at assessing factors of dog rabies maintenance in Kinshasa (capital of DRC) and at proposing an integrated, efficient and sustainable rabies control program.

The thesis was carried out mainly in three peri-urban communes of Mont-Ngafula, Ngaliema Lemba where most confirmed dog rabies have been reported from 2003 to 2017. Several tools have been used in order to achieve the goal of thesis: (i) household questionnaire survey conducted in 22 study sites (quartiers) for assessing dog density, dog-keeping practices and rabies vaccination coverage as risk factors of rabies maintenance and establishment of low scale risk maps; (ii) GPS tracking of owned dog movements (n=16) for estimation of the maximal distance covered and the potential contact rate; (iii) street-count method for estimation of proportion of feral dogs; (iv) serological test (RFFIT: rapid fluorescent focus inhibition test) for evaluation of the immunization status of reported vaccinated dogs, evaluation of rabies vaccine efficacy and duration of immunity; (v) longitudinal questionnaire survey for estimation of the turnover rate in relation with roaming activity; (vi) vaccination compartmental model; and (vii) stakeholder analysis method for the description of existing rabies network and the assessment of level of collaboration among stakeholders.

This research evidenced that the poor dog-keeping practices and the low vaccination coverage were the main risk factors of rabies maintenance in dog population. Indeed, the majority of dogs (mean 60%) were free- roaming dogs. Yet, most (≥60%) of them were not vaccinated against rabies and within 24 hours, a roaming dog had a chance to come in contact with 30 dogs. Both factors in combination with dog density allowed to establish three risk zones (n=22): high (41%), medium (32%) and low (27%) risk zones. These risk zones varied locally and were influenced by the socio-economic status of dog-owning households. In addition, the annual turnover rate of dog population was influenced by the dog-keeping practices. It was low (17%) in low roaming population (25%) and high (36%) in high roaming population (≥75%). The vaccine was effective in 98% (81/83) of dogs including puppies (2-3 months) and was found to protect for 3 years at least. Consequently, it was hypothesized that vaccine may provide a lifetime protection against rabies for the majority of the investigated dog population. The model based on systematic vaccination of puppies at 3 months of age was preventing the decrease of the vaccination coverage even in settings with high turnover rate (36%). Finally, the thesis revealed that the existing rabies network was made up mainly of institutions of medical and veterinary sectors. However, the collaboration between both sectors was weak, thereby leading to lack of sustainable framework for implementation of rabies control program.

The implementation of an integrated, efficient and sustainable theoretical rabies control program is feasible through (i) stratification of risk zones and prioritization of high risk zones, (ii) systematic vaccination of puppies at 3 months of age and, (iii) creation of a sustainable framework based on strong collaboration among stakeholders and community engagement.

 

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