Rinderpest experience

Rinderpest, the most dreaded disease of cattle, originated as far back as the domestication of cattle, occurring in Asia more than 10,000 years ago. It has been the main preoccupation of Veterinary Service activities for many centuries and was the major motivation for establishing the first veterinary school in Lyon, France, in 1761. Gaining control of the disease was the impetus for the founding of many regional and international organisations (including the World Organisation for Animal Health). Outbreaks of rinderpest have led to food shortages and starvation, economic losses and poverty, social unrest, and disrupted transport networks in regions where agriculture was dependent on draught cattle. The rinderpest virus, causative agent of the disease, has also been used as a biological weapon in the past. Many regional rinderpest eradication campaigns have been implemented, including Joint Project 15; the Pan-African Rinderpest Campaign (PARC); the South Asia Rinderpest Eradication Campaign; the West Asia Rinderpest Eradication Campaign; and the Pan African Programme for the Control of Epizootics. All of these campaigns were supported by regional and international organisations, and the disease was finally eradicated in 2011. The benefit of PARC in terms of the value of avoided losses in cattle products due to the decrease in the disease's occurrence was estimated to be between 581,000 and 35,433,000 European currency units. Currently, the world is prepared to prevent the deliberate or accidental release of the remaining infectious rinderpest virus material which exists in research and diagnostic facilities across the world.

International reference standards: antibody standards for the indirect enzyme-linked immunosorbent assay

Reference standards are used to calibrate similar assay systems against an international reference protocol and to provide a template for the preparation of secondary and/or working standards. Three reference standards are recommended for the indirect enzyme-linked immunosorbent assay: a strong positive standard, a weak positive standard and a negative serum standard. The negative standard should be derived from a single serum or from a serum pool which exhibits typical background activity in the reference protocol. The strong and weak positive standards should be derived from a single serum or from a serum pool which typifies the humoral response (antibody) to natural infection. Suitable candidates for the positive reference standards should exhibit dose/response curves in the mid-range of antibody activity. The strong and weak positive standards should each be prepared from a one-time dilution in the negative standard, to yield antibody activities which are defined by specific points on the linear portion of the dose/response curve. The strong positive standard should represent an antibody activity (absorbance value) midway between the upper and central points and the weak positive standard should represent an antibody activity midway between the central and lower points of the linear portion of the curve. Owing to inherent differences among assay systems, antibody activities should be expressed in relative rather than in absolute terms. It is recommended that the antibody activity of the strong positive standard should denote 100% positivity. The activities of the weak positive and negative standards should then be expressed as relative percentages. Every set of international reference standards should be accompanied by an information sheet which includes, among other things, a plot of the dose/response curve and an indication of the dilutions used to prepare the standards.

[Epidemiology of rinderpest and cattle plague in Mali: serological surveys]

Within the epidemiological surveillance of rinderpest in Mali a serological survey has been carried out on 58 herds of small ruminants. Out of 567 tested sera for the detection of antibodies against rinderpest 2 were positive. These sera were collected from two animals over 6 years old, probably infected during the last outbreak of rinderpest in Mali in 1986. Therefore, it can be assumed that the rinderpest virus has not circulated in Mali since that year. However, the infection rate among goats and sheep due to the PPR virus seemed to be high: 74% of herds had already been infected. The prevalence of individual infection is 32%. A similar serological survey was conducted on 450 cattleheads, without antibodies against the rinderpest virus and showed that 1.78% of these animals had been in contact with the PPR virus. With such a low infection rate in cattle, the PPR virus probably has no incidence in the epidemiology of rinderpest in Mali.

[Epidemiology of bovine brucellosis in Mali: serologic investigation and initial isolation of strains of Brucella abortus]

The authors report the results of an epidemiological survey of bovine brucellosis in Mali, based on a relatively representative sample of 1,000 serum samples from 236 herds. The prevalence of infection in the herds, established by indirect enzyme-linked immunosorbent assay (ELISA) was 53% +/- 6.4. The proportion of animals infected was 23.3% +/- 2.5, falling to 22% when compared with the basic serum pool of 9,466 samples. This rate was relatively high in stationary herds in the semi-arid, sub-humid and arid zones. Four strains of Brucella abortus were isolated from cattle bearing hygromas.