Evolutionary analysis of foot-and-mouth disease virus serotype SAT 1 isolates from east Africa suggests two independent introductions from southern Africa.
BACKGROUND
In East Africa, foot-and-mouth disease virus serotype SAT 1 is responsible for occasional severe outbreaks in livestock and is known to be maintained within the buffalo populations. Little is known about the evolutionary forces underlying its epidemiology in the region. To enhance our appreciation of the epidemiological status of serotype SAT 1 virus in the region, we inferred its evolutionary and phylogeographic history by means of genealogy-based coalescent methods using 53 VP1 coding sequences covering a sampling period from 1948-2007.


RESULTS
The VP1 coding sequence of 11 serotype SAT 1 FMD viruses from East Africa has been determined and compared with known sequences derived from other SAT 1 viruses from sub-Saharan Africa. Purifying (negative) selection and low substitution rates characterized the SAT 1 virus isolates in East Africa. Two virus groups with probable independent introductions from southern Africa were identified from a maximum clade credibility tree. One group was exclusive to Uganda while the other was present within Kenya and Tanzania.


CONCLUSIONS
Our results provide a baseline characterization of the inter-regional spread of SAT 1 in sub-Saharan Africa and highlight the importance of a regional approach to trans-boundary animal disease control in order to monitor circulating strains and apply appropriate vaccines.
Makerere University, Institute of Environment and Natural Resources, Molecular Biology Laboratory, P, O, Box 7298, Kampala, Uganda. aksangula@muienr.mak.ac.ug
Abraham K
AK
Sangula
Graham J
GJ
Belsham
Vincent B
VB
Muwanika
Rasmus
R
Heller
Sheila N
SN
Balinda
Charles
C
Masembe
Hans R
HR
Siegismund
D000351:Africa, Eastern; D000353:Africa, Southern; D001499:Bayes Theorem; D036022:Capsid Proteins / Q000235:genetics; D019143:Evolution, Molecular; D029544:Foot-and-Mouth Disease Virus / Q000145:classification / Q000235:genetics*; D058974:Phylogeography; D012367:RNA, Viral / Q000235:genetics; D012641:Selection, Genetic; D017423:Sequence Analysis, RNA
D036022:Capsid Proteins; D012367:RNA, Viral; C442501:VP1 protein, Foot-and-mouth disease virus