Megid,J*.; Almeida,M.F. ;Albas,A.
;Araujo Jr.,J.P.;Duarte,J.M.B
*Faculty of Veterinary Medicine- Dept. Veterinary Hygiene and Public Health
Email:jane@fmvz.unesp.br
Introduction Discussion References Previous Page
This report describes the presence of rabies neutralizing antibodies in wild
deer (Blastocerus dichotomus) from the western region of São Paulo State-Brazil
.This suggests a low level rabies virus infection in the cervids, possibly due
to natural transmission from infected bats in a rabies endemic region.
Rabies virus neutralizing antibodies
have been recorded previously in unvaccinated wild animals located in rabies
endemic areas (Constantine,1967; Lord et.al,1975; Carey & McLean,1983; Rosette
& Gunson,1984) . Affected species have included carnivores like foxes and
skunks (Lord et. al,1975; Rosette & Gunson,1984 ) , bats( Lord et. Al,1975)
and cattle (Lord et. Al,1975). The presence of seropositive wild species has
suggested not only a low viral titer infection in affected animals, but also
that they may play a role in the maintenance of latent rabies virus infection
(Carey & McLean,1983) .This report describes the presence of rabies serum
neutralizing antibodies in wild deer (Blastocerus dichotomus), from the western
region of São Paulo State,Brazil, a rabies endemic area.
Eight-two wild deer (B. dichotomus) were captured, examined clinically, and
translocated to new areas. Serum from each deer was analysed for the presence
of rabies neutralizing antibodies using established methods (Favoretto et al.,1993).
All deer were clinically normal when captured. Rabies titers greater than 0.5
IU were observed in 11 animals (13,4%). Seven of these (8,5%) had titers greater
than 1.0 IU and 4 (4,87%). titers of 0,5 IU There was no obvious relationship
between the presence of neutralizing antibodies and the sex or age of the deer.
Four of this animals were still live one year after the capture. The causes
of dead of seven deer were tibia-tarsal dislocation, cervical vertebral dislocation,
mites infestation and purulent pneumoniae. All the deaths were not related to
rabies symptoms or suspect. This region presents a recent rabies historical
in cattle and rabies positivity in insectivorous (Myotis nigricans) and vampire
bats (Desmodus rotundus) Bats were observed eating and flying near the deer
location, but no bats bites were observed in the animals.
The presence of rabies neutralizing antibodies was described in racoons (Carey
& McLean,1983) correlated to epizooties of rabies. The authors relate that
approximately 80% of naturally infected racoons did not succumb to infection
and did develop neutralizing antibodies. Rosette & Gunson (1984) describes
the neutralizing antibodies to rabies in skunks possible transmitted by bats
.
The presence of rabies virus neutralizing antibodies in infected and clinically
ill animals is observed only in the last period of the disease ( Campbell &
Charlton, 1988). Clinical symptoms were not observed in the deers and four of
this were still alive for one year, so we can suppose a low virus titre infection
in the deers This region presents a recent rabies historical in cattle and rabies
positivity in insectivorous (Myotis nigricans) bats. It´s important to
consider that the wild deers can move as far as 50 km during the rain period
and migration also occurs in bats . The habitat alteration by agriculture practice
and hydro-electric power station construction, can facilitate the migration
of animals (Sá,1992) and approximate cattle and bats . Although the wild
deers prefer open areas they also can penetrate in the wood and remain in closed
areas. Additionally, the immune response in animals feeding on infected material
have been demonstrated experimentally( Bell & Moore,1971). The presence
of bats feeding near the deers location was observed by several persons. Bat
rabies and carnivore-rabies associations have been described by Constantine
(1967) in vertebrates feeding on Brazilian free-tailed bats. Lord et al ( 1975)
surveyed vampire bats and carnivores after an outbreak of rabies in cattle in
Argentina. They have observed antibody positivity in cattle, in vampire bats,
foxes and skunks and they speculated that the antibodies in the carnivores was
a result of eating dead or dying rabid vampire bats.
The results suggests a low viral titer infection and subsequent production of
rabies virus neutralizing antibodies by the cervideos, justified by the endemicity
of rabies in the region with possibility of natural dissemination by bats.
BELL,J.F. & MOORE, G.J. Susceptibility
of Carnivora to Rabies Virus Administered Orally. Am. J. Epidemiol., v.93, p.176-82,1971
CAREY,A .B. & McLEAN,R.G. The Ecology of Rabies: Evidence of Co-adaptation.
J. Appl.Ecol., v.20, p.777-800,1983
CAMPBELL,J.B. & CHARLTON,K.M. Rabies. kluwer Academic Publishers. 2 v. 1988,
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CONSTANTINE, D.G. Rabies Transmission by air in bat caves. Unites States Department
of Health, Education and Welfare, Public Health Service Publication,n.1617,1967
FAVORETTO,S.R., CARRIERI,M.L.,TINO,M.S., ZANETTI,C.R., PEREIRA,O. A .C. Simplified
Fluorescence Inhibition Test for the Titration of Rabies Neutralizing Antibodies.
Rev. Inst. Med. Trop., São Paulo, v.35,p.171-5,1993
LORD,R.D., DELPIETRO,H., FUENZALIDA,E., DIAZ,A .M.O & LAZARO,L. Presence
of Rabies Neutralizing Antibodies in Wild Carnivores Following na Outbreak of
Bovine Rabies. J. Wildl. Dis. ,v.11,p.210-23,1975
ROSATTE, R.C. & GUNSON,J.R. Presence of Neutralizing Antibodies to Rabies
virus in Striped Skunks from Areas free of Skunk Rabies in Alberta. J. Wildl.
Dis., v.20, p.171-6,1984
SÁ, R.M.L.. A view of Hydroeletric dams in the Amazon, with Emphasis
on the Samuel Dam. Rondônia. TCD Newsl., v.25, p.1-4,1992