Baldet, T. (T)

Delécolle, J. (Jean-Claude)

Jaumally, M. (M) R. (R)

Jori, F. (F)

Roger, F. (F)

Roger, M. (M)

Sauzier, J. (J)

univOAK

LETTERS
Richard H. Evans
Author affi liation: Pacifi c Marine Mammal 
Center, Laguna Beach, California, USA
DOI: 10.3201/eid1702.101511
References
  1.  Butler W, Floyd M, Brown J, Toney S, 
Daneshvar M, Cooksey R, et al. Novel 
mycolic acid–containing bacteria in the 
family Segniliparaceae fam. nov., includ-
ing the genus Segniliparus gen. nov., with 
descriptions of Segniliparus rotundus sp. 
nov. and Segniliparus rugosus sp. nov. Int 
J Syst Evol Microbiol. 2005;55:1615–24. 
DOI: 10.1099/ijs.0.63465-0
  2.  Sikorski J, Lapidus A, Copeland A, Misra 
M, Glavina Del Rio T, Nolan M, et al. 
Complete genome sequence of Segnili-
parus rotundus type strain (CDC 1076T). 
Stand Genomic Sci. 2010;2:203–11. DOI: 
10.4056/sigs.791633
Address for correspondence: Richard H. Evans, 
Pacifi c Marine Mammal Center, 20612 Laguna 
Canyon Rd, Laguna Beach, CA 92651, USA: 
email: revans@pacifcmmc.org
Orbiviruses in 
Rusa Deer, 
Mauritius, 2007
To the Editor: Bluetongue and 
epizootic hemorrhagic disease are 
caused by orbiviruses transmitted by 
Culicoides spp. biting midges (Dip-
tera: Ceratopogonidae). These dis-
eases are restricted to regions where 
their vectors exist (1) and seem to be 
expanding to previously unaffected ar-
eas (2). Infection of wild and domestic 
ruminants is common. Bluetongue vi-
rus (BTV) causes severe clinical dis-
ease in certain breeds of sheep; BTV 
and epizootic hemorrhagic disease vi-
rus (EHDV) cause clinical disease in 
some species of deer (3,4).
Rusa deer (Cervus timorensis 
rusa), originally from Indonesia, 
are found in diverse countries in the 
Pacifi c region (Papua New Guinea, 
New Caledonia, New Zealand, and 
Australia). Introduced to the island of 
Mauritius in 1639, they are commonly 
raised in high numbers (≈60,000) for 
meat production (5). Mauritius is con-
sidered free from major livestock dis-
eases; its animal health surveillance is 
based mainly on clinical monitoring 
and inspection of carcasses at slaugh-
ter. To our knowledge, circulation of 
orbiviruses in Rusa deer has not been 
reported in detail in any country where 
this deer is present.
Our study was an initial screening 
survey of the deer population on the is-
land. A total of 369 deer, representing 
28 private farms, were chosen from 
a list of 42,959 deer. Blood was col-
lected at slaughter, and serum samples 
were sent to Onderstepoort Veterinary 
Institute, South Africa, to be tested for 
antibodies against orbiviruses with a 
homemade indirect ELISA. To dis-
tinguish between BTV and EHDV, 
samples positive by indirect ELISA 
were tested for BTV antibodies with 
the competitive ELISA produced by 
the Institute for Animal Health (Pir-
bright, UK). Of the samples positive 
by competitive ELISA, 3 were tested 
by serum neutralization against the 24 
BTV serotypes (cutoff value >16).
Simultaneously, Culicoides spp. 
midges were trapped in Onderstepoort-
type blacklight traps at 3 deer farms in 
coastal areas (Figure). Trapping was 
conducted 1 night at each farm, during 
optimal weather conditions. Midges 
were kept at room temperature in 95% 
ethanol until sent to Strasbourg Uni-
versity, France, for identifi cation.
Of the 369 deer serum samples 
tested, 15 were positive for BTV 
and 5 for EHDV; seroprevalence 
was 4.1% for BTV (95% confi dence 
interval 2.0%–6.1%) and 1.3% for 
EHDV (95% confi dence interval 
2.0%–6.1%). No signifi cant differenc-
es were observed for sex (χ2 = 0.05, 
312 Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 17, No. 2, February 2011
Figure. Location of farms where Rusa deer were sampled (open circles), herds with 
orbivirus-seropositive deer (closed circles), biting midge collection sites (triangles), and 
main cities (crosses) in Mauritius. Most (99%) Culicoides spp. midges were trapped at sites 
1 and 3. Inset show location of Mauritius (in square) in relation to Africa and Madagascar.
LETTERS
p = 0.82). Antibodies (indirect ELI-
SA) against orbiviruses were more 
prevalent among adults (χ2 = 4.56, p = 
0.03). The 3 samples tested by serum 
neutralization had high titers against 
BTV-2 (256, 256, and 128) and lower 
but positive titers against BTV-17 (32 
in each), BTV-10 (16 in each), and 
BTV 21 (32 in 1). Despite reports of 
clinical signs in other deer species in-
fected with both viruses (3,4), no signs 
of bluetongue or epizootic hemorrhag-
ic disease were reported for the Rusa 
deer population in our survey. This ab-
sence of clinical disease might be the 
result of natural resistance of this spe-
cies to orbiviruses or to the fact that 
the circulating serotypes are endemic 
to the area.
A total of 13,356 Culicoides spp. 
midges were obtained; 12% were iden-
tifi ed as C. imicola (1,459 females, 
138 males) and 88% as C. enderleini 
(8,800 females, 2,878 males). The for-
mer species has been reported in Mau-
ritius (6). In our study, the positive 
serum came from deer on 4 farms lo-
cated in the coastal area. This fi nding 
could indicate a higher abundance and 
activity of C. imicola midges in coast-
al areas, where climate and altitude are 
more favorable for the vector.
Serum neutralization results sug-
gested that at least 4 serotypes could 
have been circulating in deer from 
Mauritius. During outbreaks of both 
viruses in neighboring Réunion Is-
land, several serotypes of BTV were 
isolated from sheep (7,8) and of 
EHDV from cattle (9). However, BTV 
serotypes 17 and 21 have never been 
isolated from Indian Ocean countries, 
and serotype 21 has been detected 
only in Australia (2). Equally, diverse 
BTV serotypes circulate at different 
locations on the Indian Ocean and the 
east coast of Africa (2,5,6).
Our results provide serologic 
indication that EHDV and BTV cir-
culate in Rusa deer in Mauritius. 
The large population of Rusa deer 
can represent a potential reservoir 
host for those viruses and a risk for 
transmission to other ruminants in 
Mauritius and neighboring countries. 
However, Rusa deer could be used 
as a sentinel population to regularly 
monitor the circulation of orbiviruses 
and the introduction of new serotypes 
to Mauritius. To detect and isolate 
circulating serotypes and genotypes 
of these viruses in ruminant species 
and in potential vectors in Mauritius, 
further research is needed. In addi-
tion, the extent of both viruses and 
the distribution of Culicoides midges 
over the island should be investigated 
in more detail.
Acknowledgments
We thank the Division of Veterinary 
Services of Mauritius for providing logis-
tical assistance and laboratory facilities, 
all deer herd managers for their collabora-
tion, and Truuske Gerdes for reviewing the 
manuscript and advising with regard to the 
analysis.
This work was supported with the 
funds from the French Ministry of Foreign 
Affairs within the project “Support to the 
harmonization of epidemiological surveil-
lance networks for livestock diseases” 
(FSP project no. 2003–067).
Ferran Jori, Matthieu Roger, 
Thierry Baldet, 
Jean-Claude Delécolle, 
Jacqueline Sauzier, 
Mahmad Reshad Jaumally, 
and François Roger
Author affi liations: French Agricultural Re-
search Center for International Develop-
ment (CIRAD), Montpellier, France (F. Jori, 
F. Roger); University of Pretoria, Pretoria, 
South Africa (F. Jori); CIRAD, Sainte-Clotil-
de, La Réunion Island, France (M. Roger); 
CIRAD, Cotonou, Bénin (T. Baldet); Uni-
versité de Strasbourg, Strasbourg, France 
(J.C. Delécolle); Mauritius Deer Farming 
Coopérative Society Ltd, Curepipe, Mauri-
tius (J. Sauzier); and Ministry of Agro Indus-
try and Fisheries, Réduit, Mauritius (M.R. 
Jaumally)
DOI: 10.3201/eid1702.101293
References
  1.  Mellor PS, Boorman J, Baylis M. Cu-
licoides biting midges: their role as ar-
bovirus vectors. Annu Rev Entomol. 
2000;45:307–40. DOI: 10.1146/annurev.
ento.45.1.307
  2.  MacLachlan NJ, Guthrie AJ. Re-emer-
gence of bluetongue, African horse 
sickness, and other orbivirus diseases. 
Vet Res. 2010;41:35. DOI: 10.1051/
vetres/2010007
  3.  Haigh JC, Mackintosh C, Griffi n F. Viral, 
parasitic and prion diseases of farmed deer 
and bison. Rev Sci Tech. 2002;21:219–
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  4.  Gaidos JK, Crum JM, Davidson WR, 
Cross SA, Owen SF, Stallknecht DE. Epi-
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sickness viruses in Mauritius. Med Vet 
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j.1365-2915.1992.tb00622.x
  7.  Breard E, Sailleau C, Hamblin C, Zientara 
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  8.  Barré N, Eramus BJ, Gautier A, Reme A, 
Valin R. La bluetongue, nouvelle maladie 
des ovins à la Réunion (Océan Indien). Rev 
Elev Med Vet Pays Trop. 1985;38:16–21.
  9.  Breard E, Sailleau C, Hamblin C, Graham 
SD, Gourreau JM, Zientara S. Outbreak of 
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land of Réunion. Vet Rec. 2004;155:422–3. 
DOI: 10.1136/vr.155.14.422
Address for correspondence: Ferran Jori, 
CIRAD-UPR AGIRs, Department ES TA 
30/E, Campus International de Baillarguet, 
Montpellier 34080, France; email: jori@
cirad.fr
 Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 17, No. 2, February 2011 313 


Orbiviruses in Rusa deer, Mauritius, 2007

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