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

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, 2419 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% (1645/2620 positive) whereas during the second half (1998-2006) it was estimated at 45.91 +/- 2.38% (774/1686 positive) and the difference between the two estimates was statistically, highly significant (delta % = 16.88, SE(95) diff % = 3.015, SD = 5.599; P < 0.001). Ruminant rabies accounted for 79.99% (50.92% bovine, 928.40% 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.

A serological survey for antibodies to foot-and-mouth disease virus in indigenous Tswana goats and sheep in Kasane, Maun and Shakawe districts in northwestern Botswana.

A serological survey was conducted in apparently healthy, unvaccinated indigenous Tswana goats and sheep in Kasane, Maun and Shakawe districts in northwestern Botswana in order to determine in these animals, the levels of exposure to the South African Territories (SAT) serotypes: SAT 1, SAT 2 and SAT 3 of foot-and-mouth disease virus (FMDV). A total of 250, 142 and 134 goat sera originating respectively from Kasane, Maun and Shakawe districts were tested for FMDV antibodies against the three SAT serotypes by the liquid phase blocking enzyme-linked immunosorbent assay and 26 of 250 (10.4%), 5 of 142 (3.5%) and 18 of 134 (13.4%) were positive either to SAT 1 or SAT 3, or to both serotypes. None of the goats' sera was positive to SAT 2 serotype. All sheep sera (n = 9) tested negative against all three serotypes of the virus. The findings are discussed in relation to results of other serological surveys carried out elsewhere.

Molecular epidemiology of rabies in Botswana: a comparison between antibody typing and nucleotide sequence phylogeny.

A panel of rabies virus isolates (RABV) endemic within Botswana between 1988 and 1992 have been typed by anti-nucleocapsid monoclonal antibodies (MAb) into two dominant groups. The first associated with the domestic dog (Canis familiaris) and the second associated with a range of wildlife species. Using nucleoprotein coding sequence data, we have applied molecular phylogenetic techniques to the same panel of 35 well-characterised rabies virus isolates from throughout Botswana in an attempt to compare both techniques and to further investigate the virus/host species relationships within this African country. The results confirm that there are indeed two major groups and that these are related primarily to biotype. The wildlife-associated biotype appeared more phylogenetically diverse and was more commonly isolated in the southeast of the country, with the canine-associated group dominating the north of the country. In addition, molecular phylogeny identified further groupings within both biotypes and a small number of isolates, which were not classified by MAb typing, could be assigned to a group. During the study period (4 years) there appeared to be little sequence variation within groups suggesting that distinct lineages persisted throughout the study and that there appears to be little evolutionary pressure on the nucleoprotein coding region of the viral genome.

Re-emergence of foot-and-mouth disease in Botswana.

The re-emergence of foot-and-mouth disease (FMD) in Botswana is reported. The disease outbreak occurred in the Matsiloje Extension Area of Francistown veterinary district situated in the northeastern part of the country in an Office International des épízooties (OIE) recognized FMD free zone without vaccination. The disease affected cattle only and did not spillover into sheep and goats resident in the same extension area, as demonstrated by lack of seroconversion to FMD when tested. The virus isolate associated with the outbreak was identified as FMD virus; Southern African Territories (SAT) type SAT-2. The disease outbreak is discussed in relation to FMD outbreaks that have occurred previously within and outside Botswana.

The control of foot-and-mouth disease in Botswana: special reference to vaccination.

Botswana has a history of Foot-and-Mouth Disease (FMD) occurrence and control that dates far back into the 1930s. Conditions in the southern African region are favourable for spiking FMD outbreaks due to Southern African Territories (SAT) serotypes, because of the co-existence of the agent, hosts and a conducive environment. In the past these parameters were less controlled and FMD outbreaks were common in the region, causing tremendous social and economic losses. The inception of conventional FMD vaccines in the region in the 1970s led to a significant improvement in the control of the disease. Vaccination used with other appropriate strategies has been the cornerstone of FMD control strategy in Botswana. FMD vaccine used in Botswana is manufactured locally; it is effective and has been responsible for the elimination of FMD outbreaks since the early eighties. FMD vaccination is a costly exercise. The programme has been sustained for decades because there is political will and financial support from government. However, its economic value can only be determined through a cost-benefit analysis, which is not a subject of this paper. The experience of FMD control in Botswana, with special reference to vaccination, is discussed.

Goat-sheep hybrid born under natural conditions in Botswana.

In Botswana it is common practice to rear goats (Capara hircus) and sheep (Ovis aries) together in one kraal. Under such conditions it is also not uncommon to see the two species mating, but such matings have never been reported to produce a viable offspring. In this field observation a viable offspring was born naturally from a mating between a female goat and a male sheep. Chromosomal analysis showed that the hybrid had 57 chromosomes, intermediate between the 60 possessed by its dam and the 54 possessed by its sire. In August 1999 the hybrid was five years old.