Browsing by Author "Knowles, N. J"

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Epidemiological patterns of foot-and-mouth disease worldwide
(Transboundary and emerging diseases, 2008-04) Rweyemamu, M; Roeder, P; Mackay, D; Sumption, K; Brownlie, J; Leforban, Y; Valarcher, J.-F; Knowles, N. J; Saraiva, V
Foot-and-Mouth Disease (FMD) is a clinical syndrome in animals due to FMD virus that exists in seven serotypes, whereby recovery from one sero-type does not confer immunity against the other six. So when considering intervention strategies in endemic settings, it is important to take account of the characteris- tics of the different serotypes in different ecological systems. FMD serotypes are not uniformly distributed in the regions of the world where the disease still occurs. For example, the cumulative incidence of FMD serotypes show that six of the seven serotypes of FMD (O, A, C, SAT-1, SAT-2, SAT-3) have occurred in Africa, while Asia contends with four sero-types (O, A, C, Asia-1), and South America with only three (O, A, C). Periodically there have been incur- sions of Types SAT-1 and SAT-2 from Africa into the Middle East. This paper describes the global dynamics for the seven sero-types and attempts to define FMD epidemiological clusters in the different regions of the world. These have been described on a continent by continent basis. The review has reaffirmed that the movement of infected animals is the most important factor in the spread of FMD within the endemically infected regions. It also shows that the eco-system based approach for defining the epidemiolo- gical patterns of FMD in endemic, which was originally described in South America, can apply readily to other parts of the world. It is proposed that any coordinated regional or global strategy for FMD con- trol should be based on a sound epidemiological assessment of the incidence and distribution of FMD, identifying risk sources as either primary or second- ary endemic eco-systems.
Molecular characterization of foot-and-mouth disease viruses collected in Tanzania between 1967 and 2009
(Trans boundary and Emerging Disease, 2014-06-12) Kasanga, C. J; Wadsworth, J; Mpelumbe-Ngeleja, C. A. R; Sallu, R; Kivaria, F; Wambura, P. N; Yongolo, M. G. S; Rweyemamu, M. M; Knowles, N. J; King, D. P
This paper describes the molecular characterization of foot-and-mouth disease viruses (FMDV) recovered from outbreaks in Tanzania that occurred between 1967 and 2009. A total of 44 FMDV isolates, containing representatives of sero- types O, A, SAT 1 and SAT 2 from 13 regions of Tanzania, were selected from the FAO World Reference Laboratory for FMD (WRLFMD) virus collection. VP1 nucleotide sequences were determined for RT-PCR amplicons, and phylogenetic reconstructions were determined by maximum likelihood and neighbour-joining methods. These analyses showed that Tanzanian type O viruses fell into the EAST AFRICA 2 (EA-2) topotype, type A viruses fell into the AFRICA topotype (geno- type I), type SAT 1 viruses into topotype I and type SAT 2 viruses into topotype IV. Taken together, these findings reveal that serotypes O, A, SAT 1 and SAT 2 that caused FMD outbreaks in Tanzania were genetically related to lineages and topotypes occurring in the East African region. The close genetic relationship of viruses in Tanzania to those from other countries suggests that animal move- ments can contribute to virus dispersal in sub-Saharan Africa. This is the first molecular description of viruses circulating in Tanzania and highlights the need for further sampling of representative viruses from the region so as to elucidate the complex epidemiology of FMD in Tanzania and sub-Saharan Africa.