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BMC Vet Res. 2016 Jan 6;12:5. doi: 10.1186/s12917-015-0616-1.

Unrecognized circulation of SAT 1 foot-and-mouth disease virus in cattle herds around Queen Elizabeth National Park in Uganda.

Author information

1
National Animal Disease Diagnostics and Epidemiology Centre, Ministry of Agriculture Animal Industry and Fisheries, P. O. Box 513, Entebbe, Uganda. dhikusookatefulamoses@gmail.com.
2
National Animal Disease Diagnostics and Epidemiology Centre, Ministry of Agriculture Animal Industry and Fisheries, P. O. Box 513, Entebbe, Uganda. cayebazibwe@gmail.com.
3
National Animal Disease Diagnostics and Epidemiology Centre, Ministry of Agriculture Animal Industry and Fisheries, P. O. Box 513, Entebbe, Uganda. alicenmtv207@gmail.com.
4
Department of Biotechnical and Diagnostic Sciences, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda. alicenmtv207@gmail.com.
5
National Veterinary Institute, Technical University of Denmark, Lindholm, Kalvehave, DK 4771, Denmark. grbe@vet.dtu.dk.
6
Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK 2200, Copenhagen N, Denmark. hsiegismund@bio.ku.dk.
7
Foot-and-Mouth Disease Laboratory, Ministry of Livestock Development, P. O. Box 18021, Embakasi, Nairobi, Kenya. snabalayo@yahoo.com.
8
Department of Environmental Management, College of Agricultural and Environmental Sciences, Makerere University, P. O. Box 7062, Kampala, Uganda. snabalayo@yahoo.com.
9
Department of Environmental Management, College of Agricultural and Environmental Sciences, Makerere University, P. O. Box 7062, Kampala, Uganda. sbalinda@gmail.com.
10
Department of Environmental Management, College of Agricultural and Environmental Sciences, Makerere University, P. O. Box 7062, Kampala, Uganda. vmuwanika@muienr.mak.ac.ug.
11
National Veterinary Institute, Technical University of Denmark, Lindholm, Kalvehave, DK 4771, Denmark. kitj@vet.dtu.dk.

Abstract

BACKGROUND:

Foot-and-mouth disease (FMD) is endemic in Uganda in spite of the control measures used. Various aspects of the maintenance and circulation of FMD viruses (FMDV) in Uganda are not well understood; these include the role of the African buffalo (Syncerus caffer) as a reservoir for FMDV. To better understand the epidemiology of FMD at the livestock-wildlife-interface, samples were collected from young, unvaccinated cattle from 24 pastoral herds that closely interact with wildlife around Queen Elizabeth National Park in Uganda, and analysed for evidence of FMDV infection.

RESULTS:

In total, 37 (15%) of 247 serum samples had detectable antibodies against FMDV non-structural proteins (NSPs) using a pan-serotypic assay. Within these 37 sera, antibody titres ≥ 80 against the structural proteins of serotypes O, SAT 1, SAT 2 and SAT 3 were detected by ELISA in 5, 7, 4 and 3 samples, respectively, while neutralizing antibodies were only detected against serotype O in 3 samples. Two FMDV isolates, with identical VP1 coding sequences, were obtained from probang samples from clinically healthy calves from the same herd and are serotype SAT 1 (topotype IV (EA-I)). Based on the VP1 coding sequences, these viruses are distinct from previous cattle and buffalo SAT 1 FMDV isolates obtained from the same area (19-30% nucleotide difference) and from the vaccine strain (TAN/155/71) used within Uganda (26% nucleotide difference). Eight herds had only one or a few animals with antibodies against FMDV NSPs while six herds had more substantial evidence of prior infection with FMDV. There was no evidence for exposure to FMDV in the other ten herds.

CONCLUSIONS:

The two identical SAT 1 FMDV VP1 sequences are distinct from former buffalo and cattle isolates from the same area, thus, transmission between buffalo and cattle was not demonstrated. These new SAT 1 FMDV isolates differed significantly from the vaccine strain used to control Ugandan FMD outbreaks, indicating a need for vaccine matching studies. Only six herds had clear serological evidence for exposure to O and SAT 1 FMDV. Scattered presence of antibodies against FMDV in other herds may be due to the occasional introduction of animals to the area or maternal antibodies from past infection and/or vaccination. The evidence for asymptomatic FMDV infection has implications for disease control strategies in the area since this obstructs early disease detection that is based on clinical signs in FMDV infected animals.

PMID:
26739166
PMCID:
PMC4704403
DOI:
10.1186/s12917-015-0616-1
[Indexed for MEDLINE]
Free PMC Article

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