Peste des petits ruminants (PPR) in Ethiopia: analysis of a national serological survey.
BACKGROUND
Peste des petits ruminants (PPR) is a contagious viral disease of small ruminants in Africa and Asia. In 1999, probably the largest survey on PPR ever conducted in Africa was initiated in Ethiopia where 13 651 serum samples from 7 out of the 11 regions were collected and analyzed by competitive enzyme-linked immunosorbent assay (cELISA). The objective of this paper is to present the results of this survey and discuss their practical implications for PPR-endemic regions.


METHODS
We explored the spatial distribution of PPR in Ethiopia and we investigated risk factors for positive serological status. Intracluster correlation coefficients (rho), were calculated for 43 wereda (administrative units).


RESULTS
Seroprevalence was very heterogeneous across regions and even more across wereda, with prevalence estimates ranging from 0% to 52.5%. Two groups of weredas could be distinguished on the basis of the estimated rho: a group with very low rho (rho < 0.12) and a group with very high rho (rho > 0.37).


CONCLUSIONS
The results indicate that PPRV circulation has been very heterogeneous, the values for the rho may reflect the endemic or epidemic presence of the virus or the various degrees of mixing of animals in the different areas and production systems. Age appears as a risk factor for seropositive status, the linear effect seeming to confirm in the field that PPRV is highly immunogenic. Our estimates of intracluster correlation may prove useful in the design of serosurveys in other countries where PPR is of importance.
Waret-Szkuta
Agnès
A
Epidemiology Division, Department of Veterinary Clinical Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Herts. AL9 7TA, UK. awaret@rvc.ac.uk
Roger
François
F
Chavernac
David
D
Yigezu
Laikemariam
L
Libeau
Geneviève
G
Pfeiffer
Dirk U
DU
Guitián
Javier
J
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D005002:Ethiopia / Q000453:epidemiology; D005843:Geography; D015511:Goat Diseases / Q000453:epidemiology*; D006041:Goats; D029021:Peste-des-Petits-Ruminants / Q000453:epidemiology*; D018107:Peste-des-petits-ruminants virus / Q000276:immunology*; D015995:Prevalence; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology*
D000914:Antibodies, Viral
Virus Res. 1996 Aug;43(2):149-53
8864204
Vet Microbiol. 2004 Jan 14;98(1):3-15
14738776
Prev Vet Med. 1997 Jul;31(1-2):147-50
9234433
Prev Vet Med. 2005 Jun 10;69(1-2):63-75
15899297
Trop Anim Health Prod. 1994 May;26(2):69-73
7941031
Emerg Infect Dis. 2002 Jul;8(7):708-12
12095439
Vaccine. 1993;11(9):961-4
8212844
Rev Elev Med Vet Pays Trop. 1989;42(3):311-9
2485537
Rev Sci Tech. 1990 Dec;9(4):935-81
2132714
Vet Rec. 1991 Feb 2;128(5):110
2024417
Virology. 1993 Apr;193(2):1010-2
8460473
Prev Vet Med. 2005 Aug 12;70(1-2):51-7
15967242
Vet Microbiol. 1996 Aug;51(3-4):207-16
8870184
Vet Microbiol. 1990 May;22(4):341-52
2114052
Rev Sci Tech. 2004 Dec;23(3):807-19
15861876
Res Vet Sci. 1995 Sep;59(2):106-9
8525096
Clin Diagn Lab Immunol. 2005 Apr;12(4):542-7
15817764
BMC Med Res Methodol. 2004 Apr 28;4:9
15115554