Published Date: 2012-05-07 23:00:36
Subject: PRO/AH/EDR> Foot & mouth disease - Middle East: Egypt, Libya, Palest Auth, genotyping
Archive Number: 20120507.1125683
FOOT & MOUTH DISEASE - MIDDLE EAST: EGYPT, LIBYA, PALESTINIAN AUTHORITY, GENOTYPING
A ProMED-mail post
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International Society for Infectious Diseases
Date: Mon 7 May 2012
From: Nick Knowles <email@example.com> [edited]
Foot-and-mouth disease: North Africa and Middle East
Foot-and-mouth disease (FMD) is endemic in much of the Middle East (serotypes O, A, and sporadically Asia1) and sub-Saharan Africa (mostly due to serotypes O, A, SAT1, and SAT2).
Sporadic epidemics of FMD occur in many North African countries . As far as we are aware, Libya was FMD-free between 1994 (type O introduced from Egypt or the Middle East) and 2003 (SAT2 introduced from sub-Saharan Africa). The situation in Egypt has been less clear with FMD being reported on regular basis. Between 1964 and 2005 only serotype O was reported, with the exception of 1972 when type A was introduced from sub-Saharan Africa . However, in 2006, another type A virus was introduced into Egypt from sub-Saharan Africa . This virus caused a large number of outbreaks and requiring vaccination against this serotype to be introduced. A further increased FMD incidence has been reported in Egypt since February 2012.
In 2012, samples from outbreaks of FMD in Bahrain, Egypt, Libya, Palestinian Authority, and the Palestinian Autonomous Territories [PAT] (Gaza Strip) have been received by the FAO World Reference Laboratory for FMD at the Institute for Animal Health, Pirbright, UK. FMDV serotype SAT2 was isolated from each set of samples and subjected to RT-PCR and sequencing of the VP1 gene.
The results of VP1 sequencing showed that the viruses from Libya belonged to SAT2 topotype VII (14 SAT2 topotypes have been defined). Similarly, it was found that the Egyptian and Palestinian viruses also belonged to SAT2 topotype VII. However, within this topotype the VP1 sequences of the Egyptian viruses fell into 2 distinct lineages while the Libyan viruses were in a 3rd distinct lineage. Each lineage differed by more than 10 percent of the nucleotides in VP1. One genetic lineage, designated SAT2/VII/Ghb-12, has been found in the Egyptian provinces of Faiyum, Gharbia, Giza, Kafr el-Sheikh, Minya, Monufia, Qalyubia, and Suez. The 2nd lineage, named SAT2/VII/Alx-12, has been detected in Alexandria province. The 3rd lineage, SAT2/VII/Lib-12, was found in Benghazi, Libya. These differences suggest an independent introduction of FMDV SAT2 into Libya and either 2 independent introductions or a single introduction of 2 lineages into Egypt, all presumably from one or more sub-Saharan African countries. The VP1 sequence of the virus from the Gaza Strip was closely related to the Ghb-12 Egyptian lineage.
Surprisingly, when the VP1 sequence of the Bahrain SAT2 was determined it belonged to topotype IV and was most closely related to viruses occurring in Kenya in 2009. The cattle affected in Bahrain were being held in quarantine following their importation from Saudi Arabia.
The SAT2 VII topotype has previously been found in Eritrea (1998), Cameroon (2000, 2005), Niger (2005), Sudan (2007), Nigeria (2007-2008), and Senegal (2009) and has also previously been introduced into Saudi Arabia (2000), Kuwait (2000), and Libya (2003). The SAT2 topotype IV normally occurs in Kenya and Tanzania and has been found in Burundi and northern Malawi. This topotype was also found for the 1st and only time in cattle in Awassa, Ethiopia in 1989 and in an abattoir in Sanaa, Yemen in 1990 (in a goat imported from Sudan).
We have also determined the genome sequences of one of the Egyptian SAT2/VII/Ghb-12 viruses and the closely related virus from the Gaza Strip (GenBank accession numbers JX014255 and JX014256). The 2 genomes were 8080 nucleotides (nt) in length [with primers regions, poly(C) tract and poly(A) tail not included] and differed by 43 nt and by 9 amino acids. Genome sequencing of a SAT2 virus from Bahrain is in progress. Further sequencing of the Egypt SAT2/VII/Alx-12 virus will be performed in the future along with other viruses from the region.
In addition to these recent cases due to serotype SAT2, a new FMDV type A lineage (which we have named A/AFRICA/G-IV[ISM-12]) was also detected in Egypt in 2012. This was found to be most closely related to viruses from Sudan and Eritrea suggesting yet another recent introduction of FMDV from sub-Saharan Africa.
Therefore, the FMD situation in Egypt has become extremely complex with the presence of at least 5 distinct FMDV lineages between 2010 and 2012, requiring at least 3 different vaccine virus strains. Below are shown the different FMDV lineages present in the region in the last few years. To assist in the differentiation of these viruses we have designated names shown below for the various lineages and sub-lineages. The nomenclature is coded as serotype/topotype/lineage[sub-lineage] (years recorded).
O/ME-SA/Egy-72 (vaccine-like) (2006-2009)
A/AFRICA/G-VII[KEN-05] (2006 and 2009)
O/ME-SA/PanAsia-2[EGY-09] (2009 and 2011)
Palestinian Autonomous Territories:
Detailed genotyping reports can be found at http://www.wrlfmd.org/fmd_genotyping/.
The spread of SAT2 into the Middle East is of great concern to countries in the region and to European nations since further spread may be possible. For example, in January 1962, FMDV SAT1 was introduced into Bahrain from East Africa. Within a few months it had spread to Iran, Iraq, Israel, Jordan, Lebanon, Syria, Turkey, and Greece. The virus persisted in Iran until 1964 and Turkey until 1965. Furthermore, 2 more restricted incursions of SAT1 also occurred in 1969-1970 (Kuwait and Saudi Arabia) and 1984 (North Yemen).
Clearly close monitoring of the FMD situation in the region is now needed to define risks of future outbreaks, as well as to ensure that control measures (vaccines and diagnostic tests) are appropriate for the virus strains that are circulating. Countries in the region are encouraged to submit samples to the WRLFMD for genetic and antigenic characterisation.
1. Samuel AR, Knowles NJ, Mackay DKJ: Genetic analysis of type O viruses responsible for epidemics of foot-and-mouth disease in North Africa. Epidemiol Infect 1999; 122(3): 529-38 [available at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2809649/pdf/10459658.pdf].
2. Knowles NJ, Wadsworth J, Reid SM, et al: Foot-and-mouth disease virus serotype A in Egypt. Emerg Infect Dis 2007; 13(10): 1593-6 [available at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851527].
[Nick J. Knowles
Donald P King
Jef M Hammond
FAO World Reference Laboratory for FMD (WRLFMD)
Institute for Animal Health
Pirbright, Woking, Surrey, GU24 0NF
Nick Knowles (IAH-P)
[We are very grateful to Dr Knowles and the WRLFMD team for the comprehensive, important contribution above.
The following recent genotyping results of the 2012 FMDV strains, including dendrograms and relationships to other strains and reference (vaccine) strains, have become available to all on the WRLFMD website as follows:
Egypt A: http://www.wrlfmd.org/fmd_genotyping/2012/WRLFMD-2012-00011%20A%20Egypt%202010-2012.pdf
Egypt SAT2: http://www.wrlfmd.org/fmd_genotyping/2012/WRLFMD-2012-00011%20SAT2%20Egypt%202012%20(v2).pdf
Gaza strip, PAT SAT2: http://www.wrlfmd.org/fmd_genotyping/2012/WRLFMD-2012-00017%20SAT2%20Palestinian%20AT%202012.pdf
Bahrain SAT2: http://www.wrlfmd.org/fmd_genotyping/2012/WRLFMD-2012-00016%20SAT2%20Bahrain%202012%20v2.pdf.
The origin and route(s) of FMDV introductions during 2012 from "Sub Saharan Africa" (a general term) into the Middle East (according to acceptable terminology, this includes North Africa), is in need of further unravelling. For this end, surveillance, including samplings, should be considerably intensified. This refers to the exporting counties, such as Sudan and Ethiopia (the latter not having direct access to the Red Sea), and in particular to the ports and quarantine stations through which the consignments of exported live animals (large AND small ruminants) are transported (such as, Djibouti, Eritrea, Puntland, and Somaliland). The consignments must be identifiable and should undergo veterinary examinations and the required tests, by official veterinarians, prior and conditional to embarkation.
It deserves to be reminded, that Sudan and Ethiopia are regarded traditionally as the 2 main sources of imported animals for slaughter in Egypt.
It would also be useful if SAT2 topotype VII vaccine strains which are currently included in commercially available vaccines, such as the Eritrean topotype VII strain, be considered for inclusion among the "Most Closely Related Reference Viruses" list of viruses matched with the current field strains, in the WRLFMD genotyping programme. At this point in time, the protection rendered by the available vaccines against the current field strains is in need of confirmation. - Mod.AS]
[For the HealthMap/ProMED map of the Middle East, see http://healthmap.org/r/2jQ_. For the map showing the Palestinian Authority, see http://healthmap.org/r/2c2O. For the map showing Egypt, see http://healthmap.org/r/1zkM. For the map showing Libya, see http://healthmap.org/r/1_fL. - Mod.MPP]