Veterinary intervention in Maasailand: Infection-and-treatment vaccine against East Coast fever

In arid and semi-arid rangelands of sub-Saharan Africa, livestock are a central component of rural livelihoods and national economies, but their production is constrained by drought and disease, and exacerbated by institutional barriers and land use restrictions among other factors. Veterinary interventions may make a major difference to production measures but as with any intervention, they can also entail complex ecological and economic implications. This paper analyses the impacts of a vaccination programme for East Coast fever (ECF). ECF is the major cause of death among calves of Maasai pastoralists and agro-pastoralists and a major constraint on the livelihoods of these people. In our study sites, overall annual mortality in the calf crop due to ECF ranges from 30% to 60% depending on the rainfall (the better the rains, the higher the ECF mortalities). Our study explores the implications of vaccination for pastoralist livestock production, development and poverty and considers the potential impacts on rangeland and wildlife. Livestock mortality, sale, slaughter and exchange were measured using a multi-round survey of 72 households and a register of 1528 cattle in two study areas of different ecology and epidemiology. Livestock performance differed between the two areas, with the highland area showing higher background levels of mortality of unvaccinated animals. The infection-and-treatment method of vaccination has a major and highly significant impact on survival in both areas. Uptake of vaccination is strongly associated with a measure of wealth that includes livestock numbers and economic security, and medium and poor pastoralist households find it hard or impossible to access the full benefits of the vaccine. In one study site, vaccination was more frequent for male animals than females, suggesting an investment in vaccination for improved terms of trade. Vaccination could therefore improve livestock production without driving increasing herd numbers. However, the degree to which increasing survival due to vaccination is offset by increasing volume of trade requires further monitoring as those calves vaccinated at the start of the project reach economic maturity. Our study shows no link between vaccine uptake (or volume of trade) and scale of cultivation, suggesting little cross-investment between these livelihood activities. Vaccination potentially holds positive implications for rangeland and wildlife ecology. However, the logistics and economics of access to the vaccine mean that, under the current system of distribution, it could be driving socio-economic differentiation, rather than alleviating poverty. Alternative systems are suggested. Government and donor promotion of this and comparable interventions need to consider the poverty impacts and take measures to widen access

Veterinary intervention in Maasailand: Infection-and-treatment vaccine against East Coast fever

In arid and semi-arid rangelands of sub-Saharan Africa, livestock are a central component of rural livelihoods and national economies, but their production is constrained by drought and disease, and exacerbated by institutional barriers and land use restrictions among other factors. Veterinary interventions may make a major difference to production measures but as with any intervention, they can also entail complex ecological and economic implications. This paper analyses the impacts of a vaccination programme for East Coast fever (ECF). ECF is the major cause of death among calves of Maasai pastoralists and agro-pastoralists and a major constraint on the livelihoods of these people. In our study sites, overall annual mortality in the calf crop due to ECF ranges from 30% to 60% depending on the rainfall (the better the rains, the higher the ECF mortalities). Our study explores the implications of vaccination for pastoralist livestock production, development and poverty and considers the potential impacts on rangeland and wildlife. Livestock mortality, sale, slaughter and exchange were measured using a multi-round survey of 72 households and a register of 1528 cattle in two study areas of different ecology and epidemiology. Livestock performance differed between the two areas, with the highland area showing higher background levels of mortality of unvaccinated animals. The infection-and-treatment method of vaccination has a major and highly significant impact on survival in both areas. Uptake of vaccination is strongly associated with a measure of wealth that includes livestock numbers and economic security, and medium and poor pastoralist households find it hard or impossible to access the full benefits of the vaccine. In one study site, vaccination was more frequent for male animals than females, suggesting an investment in vaccination for improved terms of trade. Vaccination could therefore improve livestock production without driving increasing herd numbers. However, the degree to which increasing survival due to vaccination is offset by increasing volume of trade requires further monitoring as those calves vaccinated at the start of the project reach economic maturity. Our study shows no link between vaccine uptake (or volume of trade) and scale of cultivation, suggesting little cross-investment between these livelihood activities. Vaccination potentially holds positive implications for rangeland and wildlife ecology. However, the logistics and economics of access to the vaccine mean that, under the current system of distribution, it could be driving socio-economic differentiation, rather than alleviating poverty. Alternative systems are suggested. Government and donor promotion of this and comparable interventions need to consider the poverty impacts and take measures to widen access

Live immunization against East Coast fever - current status

Richard Bishop is ILRI authorThe infection-and-treatment method (ITM) for immunization of cattle against East Coast fever has historically been used only on a limited scale because of logistical and policy constraints. Recent large-scale deployment among pastoralists in Tanzania has stimulated demand. Concurrently, a suite of molecular tools, developed from the Theileria parva genome, has enabled improved quality control of the immunizing stabilate and post-immunization monitoring of the efficacy and biological impact of ITM in the field. This article outlines the current status of ITM immunization in the field, with associated developments in the molecular epidemiology of T. parva

Infection and treatment method (ITM) vaccine against East Coast fever: Reducing the number of doses per straw for use in smallholder dairy herds by thawing, diluting and refreezing already packaged vaccine

Abstract Background The Infection and Treatment Method (ITM) of vaccination is the only immunization procedure currently available to protect cattle against East Coast fever (ECF), a tick-transmitted disease responsible for losses of several hundreds of millions of dollars per year in sub-Saharan Africa. The vaccine comprises a homogenized preparation of infected ticks packaged in straws and stored in liquid nitrogen. The current manufacturing protocol results in straws containing 30–40 doses (ILRI 0804), which is impractical for immunizing small herds as found in dairy and smallholder farming systems. The ILRI 0804 SD stabilate was prepared as a 1:5 dilution of the parent stabilate, with the aim of producing vaccine stabilate straws containing between four to eight doses and thus suitable for smallholder farming systems. Infectivity of the diluted stabilate was assessed and the protective efficacy of the diluted stabilate was determined by performing experimental and field immunizations. Results Two groups of six cattle were inoculated with 1 ml of the diluted stabilate at 1:20 (equivalent to the recommended field dose for ILRI 0804, assuming no loss of sporozoite viability during thawing and refreezing) and 1:14 (assuming 30–35% loss of sporozoite viability). Schizonts were detected in all 12 animals, showing viability of sporozoites. Ten animals from the infectivity study and two control animals not previously exposed to T. parva were challenged with the parental ILRI 0804 stabilate. The results show that the two control animals displayed severe ECF reactions and were treated 14 days after challenge. Of the previously infected animals, only one underwent a severe reaction following challenge, a result in accord with the challenge experiments performed previously with the parent stabilate [Ticks Tick-Borne Dis 7:306-314, 2016]. The animal that displayed a severe reaction had no detectable schizonts and did not seroconvert following the initial inoculation with ILRI 0804 SD. In addition, 62 animals immunized under field conditions showed a mean seroconversion rate of 82%. Conclusion The results presented in this article demonstrate that it is possible to prepare straws suitable for use in smallholder herds by thawing, diluting and refreezing already packaged vaccine