Transmission dynamics and economics of rabies control in dogs and humans in an African city

• Published in: Proceedings of the National Academy of Sciences - PNAS 2009-09, Vol.106 (35), p.14996-15001
• Main Authors: Zinsstag, J, Dürr, S, Penny, M.A, Mindekem, R, Roth, F, Gonzalez, S. Menendez, Naissengar, S, Hattendorf, J
• Format: Article
• Language: English
• Subjects: Animals; Biological Sciences; Chad; Comparative analysis; Cost-Benefit Analysis; Developing countries; Disease transmission; Dog Diseases - economics; Dog Diseases - immunology; Dog Diseases - prevention & control; Dog Diseases - transmission; Dogs; Effects; Female; Health Care Costs; Humans; Immunization; Immunization Programs - economics; Intervention; LDCs; Male; Rabies; Rabies - economics; Rabies - prevention & control; Rabies - transmission; Rabies - veterinary; Rabies Vaccines - immunology; Urban Health
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0904740106

Human rabies in developing countries can be prevented through interventions directed at dogs. Potential cost-savings for the public health sector of interventions aimed at animal-host reservoirs should be assessed. Available deterministic models of rabies transmission between dogs were extended to include dog-to-human rabies transmission. Model parameters were fitted to routine weekly rabid-dog and exposed-human cases reported in N'Djaména, the capital of Chad. The estimated transmission rates between dogs (βd) were 0.0807 km²/(dogs·week) and between dogs and humans (βdh) 0.0002 km²/(dogs·week). The effective reproductive ratio (Re) at the onset of our observations was estimated at 1.01, indicating low-level endemic stability of rabies transmission. Human rabies incidence depended critically on dog-related transmission parameters. We simulated the effects of mass dog vaccination and the culling of a percentage of the dog population on human rabies incidence. A single parenteral dog rabies-mass vaccination campaign achieving a coverage of least 70% appears to be sufficient to interrupt transmission of rabies to humans for at least 6 years. The cost-effectiveness of mass dog vaccination was compared to postexposure prophylaxis (PEP), which is the current practice in Chad. PEP does not reduce future human exposure. Its cost-effectiveness is estimated at US $46 per disability adjusted life-years averted. Cost-effectiveness for PEP, together with a dog-vaccination campaign, breaks even with cost-effectiveness of PEP alone after almost 5 years. Beyond a time-frame of 7 years, it appears to be more cost-effective to combine parenteral dog-vaccination campaigns with human PEP compared to human PEP alone.