Dengue is present in the Federal District since 1991 and virological studies of the vector began in 1998. Two strains of DEN1 were isolated from 9 pools of female Aedes aegypti (78 mosq.), collected in April in Gama county, where the Breteau index was 5.4, and 32 autochtonous human cases were notified

Dégallier, Nicolas

Pereira, R.D.

Pinto, S.C.F.

Tarso R. Vilarinhos, P. de

Teixera, J.M.S.

Horizon / Pleins textes

95
Revista da Sociedade Brasileira de Medicina Tropical
33(1):95-96, jan-fev, 2000.
COMUNICAÇÃO
First isolation of  dengue 1 virus from Aedes aegypti
in Federal District, Brazil
Primeiro isolamento do vírus dengue 1 a partir de Aedes aegypti
no Distrito Federal, Brasil
Nicolas Dégallier 1 , José Marcus S. Teixeira2 , Paulo de Tarso R. Vilarinhos3,
 Santuzza C.F. Pinto2 and Regilene D. Pereira2
Abstract  Dengue is present in the Federal District since 1991 and virological studies of the
vector began in 1998. Two strains of DEN1 were isolated from 9 pools of female Aedes aegypti
(78 mosq.), collected in April in Gama county, where the Breteau index was 5.4, and 32
autochtonous human cases were notified.
Key-words: Isolation. DEN1. Aedes aegypti. Federal District.
Resumo  A dengue está presente no DF desde 1991 e estudos virológicos sobre o vetor iniciaram-
se em 1998. Duas amostras de DEN1 foram isoladas de 9 lotes de fêmeas de Aedes aegypti (78
ind.), coletadas em abril no Gama, onde o índice de Breteau era 5,4 e 32 casos autoctones
foram notificados.
Palavras-chaves: Isolamento. DEN1. Aedes aegypti. Distrito Federal.
Instituto de Saúde do Distrito Federal (ISDF), Brasília, DF, Brasil.
1. IRD, C.P. 7091 Lago Sul, 71619-970 Brasília DF, Brasil; Telefax: 0 xx 61 226-4813; E-mail: degallie@solar.com.br
2. ISDF/Virologia, SGAN Q601 lotes O e P, 70830 Brasília DF, Brasil.
3. GCZ/ISDF, SAIN, Estr. do Contorno do Bosque  lote 04, 70620-000, Brasilia DF, Brasil; E-mail: vilapaul@persocom.com.br
Financial and logistic support: National Health Foundation,  Health Institute of Federal District - Health Secretary of FD, Brasil & Research
Institute for Development (IRD, formerly ORSTOM), France.
Address to: Dr. Nicolas dégallier. C.P. 7091 Lago Sul, 71619-970 Brasília DF, Brasil; Telefax: 0 xx 61 226-4813.
E-mail: degallie@solar.com.br
Recebido para publicação em 31/3/99.
Imported dengue cases have been notified
and laboratory-confirmed in Federal District (FD)
since 19914, with 9 isolations of DEN 2 virus8. From
1993 onwards, the number of cases increased,
with detection of five autochtonous cases in 1997.
During the first half of 1998, 296 and 13 cases
were confirmed serologically (MAC ELISA) and
by viral isolation, respectively. Of these, 75 were
autochtonous, and the local transmission of DEN
1 virus was confirmed by 3 isolations. The Gama
county alone, located at the border of Goias State,
provided 32 autochtonous cases (2 DEN 1
isolates) and was thus considered a high risk area.
Entomological surveys were conducted in
houses where cases were suspected to be
autochtonous. Mosquitoes were collected as they
landed on people during afternoon. They were
anaesthetized by cold, pooled (20 spec. max.)
by species and sex, and conserved at -70° C until
inoculation. The pools were inoculated in C6/36
cell cultures (Ae. albopictus). In the absence of
cytopathic effect until the 7th day, a blind passage
was done and then tested on 14th day by indirect
immunofluorescence test with monoclonal
antibodies to dengue 1-49.
9 6
Dégallier N et al
A total of 117 mosquitoes (78 females and
39 males) was collected in 5 houses in Gama
county, and pooled (9 and 7 pools of female and
male, respectively). DEN 1 virus5  was isolated
from 2 pools of 4 Aedes aegypti  females,
collected on 27 April 1998, in Engenho das
Lages, located 30 km from Brasilia on road
BR060. Two other pools, made of 21 males, were
negative. The owner of the house from which the
positive mosquitoes originated began illness
on 1st April, thus approximately 4 weeks before
the capture of the  mosquitoes was 0.45 mosq/
man x hour (during mid afternoon) and, during
the month of April, the larval house and Breteau
indexes in Gama county were 3.8% and 5.4,
respectively.
To our knowledge, isolation of dengue virus
from Ae. aegypti in Brazil has been reported only
three times, despite the rise in epidemics during
the last 15 years3. Some attempts failed to isolate
any strain from mosquitoes, despite the great
numbers of human cases1 10. The present study
reports isolation of dengue 1 virus from adult female
mosquitoes, in a context of low transmission rate
(no. human cases / inhabitant) and low mosquito
density, in contrast with former studies in other
regions of Brazil2 7. In the study done in Niterói
during an epidemic, isolations from mosquitoes
were associated with high house and Breteau
indexes (35.2% and 102, respectively)2. On the
other hand, transmission with a low level of
mosquito density has been already reported in
Asia by K.T. Goh5, and S. K. Lam6. More studies
are necessary to understand the characteristic
eco-epidemiological factors of such regions as
the Federal District.
5isolates nr. 98043050 and 98043052
ACKNOWLEDGEMENTS
mosquitoes and to the inhabitants for their kind
collaboration.
Thanks are due to the technical staff of the
FNS and ISDF (GCZ) who collected the
REFERENCES
1. Araújo ESM, Luz DC, Santos FB, Miagostovich MP,
Schatzmayr HG, Nogueira RMR. Dengue virus type 2
epidemic in the State of Rio de Janeiro, 1995. In:
Resumos da 5° Virológica 95, Ribeirão Preto, SP p. A-
37, 1995.
2. Dégallier N, Hervé J-P, Travassos da Rosa APA,
Travassos da Rosa ES, Vasconcelos PFC, Monteiro
HAO, Sá Filho G, Travassos da Rosa JFS. Entomological
studies on Dengue fever vectors in Brazil: the epidemics
of Boa Vista, Roraima, 1982, Niteroi, Rio de Janeiro,
1986, and Ceara State, 1986, 1994. In: Travassos da
Rosa APA, Vasconcelos PFC, Travassos da Rosa JFS
(eds) An overview of arbovirology in Brazil and
neighbouring countries, Instituto Evandro Chagas,
Belém, PA p. 261-271, 1998.
3. Dégallier N, Travassos da Rosa APA, Vasconcelos PF da
C, Figueiredo LTM, Travassos da Rosa JFS, Rodrigues
SG, Travassos da Rosa ES. La dengue et ses vecteurs
au Brésil. Bulletin de la Société de Pathologie exotique
89:128-136, 1996.
4. Dusi RM, Vilarinhos PTR, Assis AL, Camara GL, Carvalho
MS. Epidemiology of dengue in Federal District, Brazil,
from 1994 to 1996. In: Abstracts of 1st International
Seminar on Dengue, Rio de Janeiro, RJ p. 65, 1996.
5. Goh KT. Changing epidemiology of dengue in Singapore.
The Lancet  346: 1098, 1995.
6. Lam SK. Prospects of Dengue surveillance and control
in Malaysia. In: Uren MF, Blok J, Manderson LH (eds)
Arbovirus Research in Australia. Proc. 5th Symp., August
28 - September 1, 1989, Brisbane, Australia p.  80-81,
1989.
7. Nogueira RMR, Schatzmayr HG, Miagostovich MP, Farias
MFDB, Farias FC. Virological study of a dengue type 1
epidemic at Rio de Janeiro. Memorias do Instituto
Oswaldo Cruz 83: 219-225, 1988.
8. Pires MFC, Teixeira JMS, Silva NC, Câmara GNL.
Investigation of dengue in Distrito Federal, Brazil. In:
Resumos da Virológica 91: II Simpósio Internacional
sobre Arbovírus dos Trópicos e Febres hemorrágicas.
Belém, PA p. 2, 1991.
9. Travassos da Rosa APA, Travassos da Rosa ES,
Travassos da Rosa JFS, Dégallier N, Vasconcelos PFC,
Rodrigues SG. Os arbovírus no Brasil: generalidades,
métodos e técnicas de estudo, doc. técn. n°2, Instituto
Evandro Chagas, Fundação Nacional de Saúde, Belém,
1994.
10. Vasconcelos PFC, Travassos da Rosa ES, Travassos da
Rosa JFS, Freitas RB, Dégallier N, Rodrigues SG,
Travassos da Rosa APA. Epidemia de febre clássica de
dengue causada pelo sorotipo 2 em Araguaina, Tocantins,
Brasil. Revista do Instituto de Medicina tropical de São
Paulo 35: 141-148, 1993.


First isolation of dengue 1 virus from Aedes aegypti in Federal District, Brazil

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