A retrospective longitudinal study of animal and human rabies in Botswana 1989-2006

Abstract

A longitudinal study of animal and human rabies covering 18 years from 1989 to 2006 was retrospectively conducted in order to highlight the epidemiological features and trends of the disease in Botswana. Over the 18-year period, a total of 4 306 brain specimens collected from various species of animals including human beings with clinical signs consistent with rabies were submitted to the National Veterinary Laboratory in Gaborone for confirmatory diagnosis. Of the samples submitted, 2 419 cases were found to be positive for lyssavirus antigen; this presents an overall prevalence rate of 56.18 ± 1.48 %. About 85.7 % (2 074/2 419) of the cases were from domestic animals, 14.2 % (343/2 419) cases were from wild animals and two cases (0.1 %) were from human beings. During the first half of the study (1989-1997) the prevalence rate of the disease was estimated at 62.79 ± 1.85 % (1 645/2 620 positive) whereas during the second half (1998-2006) it was estimated at 45.91 ± 2.38 % (774/1 686 positive) and the difference between the two estimates was statistically, highly significant (Δ % = 16.88, SE 95) diff % = 3.015, SD = 5.599; P < 0.001). Ruminant rabies accounted for 79.99 % (50.92 % bovine, 28.40 % caprine and 0.67 % ovine) whereas canine (domestic dog) and feline (domestic cat) accounted for 16.01 and 0.87 %, respectively. Equine rabies accounted for 3.13 % with 1.35 and 1.78 %, respectively, for horses and donkeys. Jackal rabies accounted for more than 60 % of the total cases in wild animals. These findings are discussed in relation to the previous epidemiological situation of the disease (1979-1988), its socio-economic impact, monitoring and control in Botswana.