Original Research

The incursion, persistence and spread of peste des petits ruminants in Tanzania: Epidemiological patterns and predictions

Fredrick M. Kivaria, Olivier Kwiatek, Angolwisye M. Kapaga, Emmanuel S. Swai, Geneviève Libeau, Winford Moshy, Albano O. Mbyuzi, Joshua Gladson
Onderstepoort Journal of Veterinary Research | Vol 80, No 1 | a593 | DOI: https://doi.org/10.4102/ojvr.v80i1.593 | © 2013 Fredrick M. Kivaria, Olivier Kwiatek, Angolwisye M. Kapaga, Emmanuel S. Swai, Geneviève Libeau, Winford Moshy, Albano O. Mbyuzi, Joshua Gladson | This work is licensed under CC Attribution 4.0
Submitted: 15 March 2013 | Published: 30 October 2013

About the author(s)

Fredrick M. Kivaria, National Epidemiology Section, Ministry of Livestock and Fisheries Development, Tanzania, United Republic of
Olivier Kwiatek, CIRAD, Campus International de Baillarguet, France
Angolwisye M. Kapaga, Central Veterinary Laboratory, Tanzania, United Republic of
Emmanuel S. Swai, Veterinary Investigation Centre, Arusha, Tanzania, United Republic of
Geneviève Libeau, CIRAD, Campus International de Baillarguet, France
Winford Moshy, Veterinary Investigation Centre, Arusha, Tanzania, United Republic of
Albano O. Mbyuzi, Veterinary Investigation Centre, Mtwara, Tanzania, United Republic of
Joshua Gladson, Central Veterinary Laboratory, Tanzania, United Republic of

Abstract

Peste des petits ruminants virus, which causes a severe disease in sheep and goats, has only recently been officially declared to be present in Tanzania. An epidemiological study was carried out between September 2008 and October 2010 to investigate the incursion, persistence and spread of the virus in Tanzania. The investigation involved serosurveillance, outbreak investigation and computation of epidemiological indices such as the effective reproductive number, persistence and the threshold level for vaccination. Field and molecular epidemiological techniques were applied to isolate, characterise and trace the origin of the virus in Tanzania. A total of 2182 serum samples from goats and 1296 from sheep from 79 villages across 12 districts were investigated. Village-level prevalence of infection was variable (0.00% – 88.00%) and was higher in pastoral than in agro-pastoral villages. The overall antibody response to the virus was 22.10% (CI 95% = 20.72% – 23.48%). About 68.00% and 73.00% of seropositive goats and sheep, respectively, did not show clinical signs. The proportion of seropositive animals differed significantly (p ≤ 0.001) between age groups, sex and farming practices. Real-time polymerase chain reaction results showed that the isolated strains belong to lineage III, whose origin is in East Africa and the Middle East. This indicates that one of the northern neighbouring countries is most likely the source of infection. The computed overall effective reproductive number, the threshold level of vaccination necessary to eradicate the disease and persistence were 4.75% and 98.00%, respectively. These estimates indicate that achieving elimination of the peste des petits ruminants virus from pastoral flocks will require significant effort and development of highly effective intervention tools.

Keywords

Effective reproductive number, Epidemic curve, Persistence, Peste des petits ruminants, Tanzania

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Crossref Citations

1. Modelling the Dynamics of Post-Vaccination Immunity Rate in a Population of Sahelian Sheep after a Vaccination Campaign against Peste des Petits Ruminants Virus
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PLOS ONE  vol: 11  issue: 9  first page: e0161769  year: 2016  
doi: 10.1371/journal.pone.0161769