STUDIES OF FILARIASIS IN KEBAN AGUNG AND GUNUNG AGUNG VILLAGES IN SOUTH BENGKULU, SUMATERA, INDONESIA : II Field identification of Mansonia Bonneae and Mansonia Dives
Vol. X I 1 No. I
Bulletin Penelitian Kesehetan
(Health Studies In Indonesia)
1984
STUDIES OF FILARIASIS IN KEBAN AGUNG AND GUNUNG AGUNG
VILLAGES IN SOUTH BENGKULU, SUMATERA, INDONESIA : I1
Field identification of Mansonia Bonneae and Mansonia Dives *
suwarto,' M. sudomo' and Lim Boo fiat2
ABSTRA CT
bonneaeldives adalah vektor potensial untuk penyakit filariasis malayi. Dua
Nyamuk Mansonia -species ini mempunyai bentuk morfologi yang mirip sekuli hanya dibedakun dengan ada tidaknya sisiksisik di antara rambut-rambut di atas pangkal sayap (supra-alarscale)dun bentuk gigi sisir (comb teeth)
pada tergit segmen abdomen ke-8. Sisik-sisik di atas pangkul sayup tersebut mudah sekali lepas sehingga
sulit untuk rnembedakan Mu. dives dun Ma. bonneae.
Penelitian untuk membedakun dua species ini secara morfologi telah dikerjakun yang kemudian
hasilnya dicocokkun dengan bentu kgigi sisir untu k masing-masing species.
Hasil pengamatan secara morfologi temyata, setelah dicocokkan dengan gigi sisir dari masingmasing specimen, Ma. dives mempunyai kesalahan identifikusi sebesar 6% sedang -Ma. bonneae 11,3%.
In our studies of mosquito vectors of malayan fdariasis in two villages at Bengkulu, Sumatera, Mansonia spp. were found to be the primary vectors of nocturnally periodic Brugia
maluyi (Suzuki et al., 1981). Among the Mansonia spp., Ma. bonneaeldives group are the most
prevalent. Female specimens of these two species
were not distingguishable from each other until
Wharton (1962) separated Ma. dives from Ma.
bonneae on the basis of the following differeces:
(a) Ma. dives bearing a small patch of pale scales
*
This study is supported by filariasis component of
the UNDP/World Bank/WHO Special Programme
for Research and Training in Tropical Diseases.
Health Ecology Research Centre, National Institute
of Health Research and Development, Ministry of
Health, P.O. Box 226, Jakarta, Indonesia.
WHO, Vector Biology and Control Research Unit-2,
P.O. Box 302, Jakarta, Indonesia.
above the wing roots (supra-alar scales), being
absent in Ma. bonneae, and (b) the difference
in the arrangement of the comb-teeth on the
eighth abdominal tergite of: Ma. dives and Ma.
bonneae. As supra-alar scales could easily drop
off due to age or rough handling it could become a source of error in morphological identification. Therefore, some workers prefer to
designate them to Ma. bonneaeldives group
rather than separating them individually.
As both these mosquitoes have been shown
to be important vectors of malayan filariasis
in Bengkulu, the separation of these mosquitoes
is important in assessing the role of each species
in the transmission dynamics of brugian fdariasis
in the study areas. In view of this, an experiment
was carried out to test the accurary of external
morphological identification based on the supraalar scales of Ma. dives and Ma. bonneae com-
Nipa palm
Swampy areas
Rice fields
Secondary forest
(rubber)
Field station
Scale 1 : 250.000
FIELD IDENTIFICATION OF MANSONIA BONNEAE AND MANSONIA DIVES
pared with the arrangement of the comb-teeth.
The aim of this experiment is t o assess validity
and reliability of field identification techniques
of these mosquitoes for base-line quantification.
to the presence or absence of the supra-alar
scales. Each sorted group was then individually
dissected to study the arrangement of the combteeth at the eighth abdominal tergite under a
compound microscope.
MATERIAL AND METHODS
The comb on the eighth abdominal tergite
of Ma. bonneae typically consists of a central
teeth group, ranging from 8-1 1 teeth flanked
on either side by a group of 1.4 lateral teeth.
There is a small detached tooth between the
central group and the lateral teeth. The combteeth arrangement is 4.1. (8-1 1) 1.4. (Fig. 2a).
For Ma. dives the comb-teeth on the eighth
abdominal tergite rarely show a detached tooth
between the central and lateral group of teeth.
The number of central comb-teeth varies from
8-12, and the lateral teeth vary from 3-5.
The comb-teeth arrangement for this species is
3-5 .O. (8-12).0.3-5 (Fig. 2b).
Females of both Ma. dives and Ma. bonneae
were frequently collected in landing collections.
Thus, catches of these mosquitoes were made
in three different places at the study areas in
Keban Agung, Gunung Agung, and in the Field
Station at Cahaya Negeri (Fig. 1). One hundred
female mosquitoes of each Ma. dives and Ma.
bonneae were collected. They were held overnight in plastic cups of not more than 25 specimens in each cup on each collection trip. The
following morning these mosquitoes were killed.
They were then visually sorted out, according
)
'
(a) Ma. bonneae
(b) Ma. dives.
Fig. 2. Showing the comb-teeth of Ma. rnansonia and Ma dives.
..* : ...... ...
... .
detached tooth
SUWARTO, ET. AL.
RESULTS
The results show that the arrangement of the
central teeth count for Ma. bonneae varies with
populations from different areas. In Gunung
Agung, it was 81% with 9 central teeth, Keban
Agung 76% with 10, and Cahaya Negeri 76%
with 11 teeth (Table 1).
Of 300 Ma. bonneae from the three areas
examined, the range of 9-1 1 central teeth count
is common as the average percentage of these
teeth count was 34.3% with 9 teeth, 33.3% with
10, and 27.0% with 11 teeth count. The 8
central teeth count is uncommon being confined to only 5.7% (Table 1). Detached tooth
between the lateral and central teeth group was
found in 99.3% of 300 specimens examined.
AU the specimens examined were found with
4 lateral teeth on each side of the comb.
For Ma. dives the arrangement of the combteeth was found to be fairly consistent between
the populations of three areas. The majority
of them were found with 10 central teeth count.
In Gunung Agung and Cahaya Negeri 80%
and 86% were with 10 central teeth count respectively, and 68% were found in Keban Agung.
Thus, it gives an average of 78% of 300 specimens examined with 10 central teeth (Table 1).
It appears that the species with 10 central
teeth is predominant, with 9 fairly common,
and with 8 or 11 central teeth uncommon in
the areas studied. There was no detached tooth
between the lateral and central teeth rows
Table 1. Percentage of Ma. bonneae and Ma. dives
with different central teeth count from
three areas
Ma. dives
Ma. bonneae
Locality
NO. of central teeth count No. of central teeth count
8
9
10
11
10
11
8
9
3
4
8
86
2
2
5
25
68
2
19
76
6
11
80
3
33.0
27.0
5.0
14.7
78.0
2.3
Gunung Agung 12
81
4
KebanAgung
3
19
76
Cahsya Negeri
2
3
Average
5.7
34.3
_
shown in any of the specimen examined. The
lateral teeth count ranged from 3-5. Of the
300 specimens examined, 92.7% was found
with 4 lateral teeth on each side of the comb,
6.0% with 3 and 1.3% with 5 only.
On visual separation of these two species
by the supra-alar scales, after each of the species
had been examined for the arrangement of
the comb teeth for confirmation, the following
results are obtained and presented in Table 2.
The results show that the reliability of external morphological characteristic identification
in the field was 88.7% for Ma. bonneae and
94.0% for Ma. dives (Table 2).
Table 2. Error (%) by supra-alar scales iden
tification for Ilia. bonneae and Ma.
dives from three areas.
I
Ma. bonrteae
Locality
*
Gunung A g u n g
.
14
1
Ma. dives
7
Agung
10
5
Cahaya Negeri
10
6
Keban
Average
11.3
6 .O
% Accuracy
88.7
94.0
DISCUSSION
The present experiment on field identification
of Ma. bonneaeldives group based on the supraalar scales, and confirmed by examination
of the comb-teeth count on the eighth abdominal
tergite, revealed that 88.7% Ma. bonneae and
94% Ma. dives could be accurately identified.
The reliability of the conventional identification
based on 'the presence of the comb-teeth is
absolute. As there is an overlap in the central
teeth count between both species, thus a more
important characteristic is the lateral teeth
count and the presence or absence of the detached tooth between the lateral and central
teeth rows in the separation of Ma. bonneae
from Ma. dives. Although error is unavoidable
by routine field examination of these mosquitoes
by the presence or absence of the supra-alar
FIELD IDENTIFICATION OF MANSONIA BONNEAE AND MANSONIA DIVES
scales, in areas when the population of these
mosquitoes are high, it would be impractical
to examine the comb-teeth count for confirmation of the species. In such situations, it may
be necessary that assessment of errors in the
identification based on visual separation by
both the presence or absence of the supra-alar
scales and count of the comb-teeth as the standard should be carried out initially as a baseline quantification.
The importance of Ma. bonneae and Ma.
dives as vectors of both forms of brugian filariasis is well documented (Lie, 1970; Wharton,
1962; Turner & Edeson, 1957; Suzuki et al.,
1981). In addition, both these species were
shown to be susceptible to Bmgia pahangi
and Dirofilaria spp. (Wharton, 1962). In our
study areas at Bengkulu, periodic B. malayi
is prevalent among the human inhabitants,
B. pahangi is common among domestic cats
(Felis cattus) and also found in a species of
carnivore (Paguma lawatus), and Dirofilaria
magizilawatum is prevalent among the nonhuman primates, Macaca fascintlaris and Presbytis cristata. It is therefore quite possible
that these mosquitoes could also be parasitized by different kinds of non-human filaria
worms. Therefore, in studying the vectorial
capacity of any of these parasites, reliable
identification of these mosquitoes is.
critical. Careful attention must also
be given when using field caught mosquitoes
of these two species for laboratoly experiments.
SUMMARY
The reliability of using external morphology
by examining the presence or absence of supraalar scales, in separating Mansonia bonneae
from Ma. dives was assessed and compared with
that using the arrangement of the comb-teeth
on the eighth abdominal tergite. It was estimated that a probability of 11 3%and 6% errors
respectively were present in the identification
of Ma. bonneae and Ma. dives on the basis
of external morphology, if comb-teeth arrangement was used as the standard.
ACKNOWLEDGEMENTS
The authors are grateful t o the field staff,
National Institute of Health Research and
Development, Jakarta and Provincial Health
Services, Bengkulu, Sumatera for their assistance
in collecting mosquitoes. To Dr E. Oswari,
Director of Health Services, Bengkulu, Dr Abu
Hanifah, Chief, CDC/Bengkulu, for their supports.
They also wish to thank Dr N.G. Gratz, Director, VBC, Geneva, Dr C.P. Pant, Chief,
ECV, Geneva for their comments, and also to
Dr Y.H. Bang, Project Leader, VBCRU-2,
Jakarta for his support.
REFERENCES
Lie, K J . (1970) The distribution of fdariasis
in Indonesia. Southeast Asian J. Trop. Med.
Publ. Hlth. 1 :366-376.
Suzuki, T., M. Sudomo, Y.H. Bang and Lim Boo
Liat (1981) Studies on malayan fdariasis
in Bengkulu (Sumatera), Indonesia with
special reference to vector confirmation.
Southeast Asian J. Trop. Med. &bl. Hlth. 12 :
47-54.
Turner, L.H. & J.F.B. Edeson (1957) Studies
on fdariasis in Malaya : The periodicity of
the microfdariae . of Wuchereria malayi.
Ann. Trop. Med. Parasitol. 51 271 -277.
Wharton, R.H. (1962) The biology of Mansonia
lnosquitoes in relation to the transmission
of fdariasis in Malaysia. Institute Med. Res.
Bull. 11 : 114 p. (Revised edition).
Bulletin Penelitian Kesehetan
(Health Studies In Indonesia)
1984
STUDIES OF FILARIASIS IN KEBAN AGUNG AND GUNUNG AGUNG
VILLAGES IN SOUTH BENGKULU, SUMATERA, INDONESIA : I1
Field identification of Mansonia Bonneae and Mansonia Dives *
suwarto,' M. sudomo' and Lim Boo fiat2
ABSTRA CT
bonneaeldives adalah vektor potensial untuk penyakit filariasis malayi. Dua
Nyamuk Mansonia -species ini mempunyai bentuk morfologi yang mirip sekuli hanya dibedakun dengan ada tidaknya sisiksisik di antara rambut-rambut di atas pangkal sayap (supra-alarscale)dun bentuk gigi sisir (comb teeth)
pada tergit segmen abdomen ke-8. Sisik-sisik di atas pangkul sayup tersebut mudah sekali lepas sehingga
sulit untuk rnembedakan Mu. dives dun Ma. bonneae.
Penelitian untuk membedakun dua species ini secara morfologi telah dikerjakun yang kemudian
hasilnya dicocokkun dengan bentu kgigi sisir untu k masing-masing species.
Hasil pengamatan secara morfologi temyata, setelah dicocokkan dengan gigi sisir dari masingmasing specimen, Ma. dives mempunyai kesalahan identifikusi sebesar 6% sedang -Ma. bonneae 11,3%.
In our studies of mosquito vectors of malayan fdariasis in two villages at Bengkulu, Sumatera, Mansonia spp. were found to be the primary vectors of nocturnally periodic Brugia
maluyi (Suzuki et al., 1981). Among the Mansonia spp., Ma. bonneaeldives group are the most
prevalent. Female specimens of these two species
were not distingguishable from each other until
Wharton (1962) separated Ma. dives from Ma.
bonneae on the basis of the following differeces:
(a) Ma. dives bearing a small patch of pale scales
*
This study is supported by filariasis component of
the UNDP/World Bank/WHO Special Programme
for Research and Training in Tropical Diseases.
Health Ecology Research Centre, National Institute
of Health Research and Development, Ministry of
Health, P.O. Box 226, Jakarta, Indonesia.
WHO, Vector Biology and Control Research Unit-2,
P.O. Box 302, Jakarta, Indonesia.
above the wing roots (supra-alar scales), being
absent in Ma. bonneae, and (b) the difference
in the arrangement of the comb-teeth on the
eighth abdominal tergite of: Ma. dives and Ma.
bonneae. As supra-alar scales could easily drop
off due to age or rough handling it could become a source of error in morphological identification. Therefore, some workers prefer to
designate them to Ma. bonneaeldives group
rather than separating them individually.
As both these mosquitoes have been shown
to be important vectors of malayan filariasis
in Bengkulu, the separation of these mosquitoes
is important in assessing the role of each species
in the transmission dynamics of brugian fdariasis
in the study areas. In view of this, an experiment
was carried out to test the accurary of external
morphological identification based on the supraalar scales of Ma. dives and Ma. bonneae com-
Nipa palm
Swampy areas
Rice fields
Secondary forest
(rubber)
Field station
Scale 1 : 250.000
FIELD IDENTIFICATION OF MANSONIA BONNEAE AND MANSONIA DIVES
pared with the arrangement of the comb-teeth.
The aim of this experiment is t o assess validity
and reliability of field identification techniques
of these mosquitoes for base-line quantification.
to the presence or absence of the supra-alar
scales. Each sorted group was then individually
dissected to study the arrangement of the combteeth at the eighth abdominal tergite under a
compound microscope.
MATERIAL AND METHODS
The comb on the eighth abdominal tergite
of Ma. bonneae typically consists of a central
teeth group, ranging from 8-1 1 teeth flanked
on either side by a group of 1.4 lateral teeth.
There is a small detached tooth between the
central group and the lateral teeth. The combteeth arrangement is 4.1. (8-1 1) 1.4. (Fig. 2a).
For Ma. dives the comb-teeth on the eighth
abdominal tergite rarely show a detached tooth
between the central and lateral group of teeth.
The number of central comb-teeth varies from
8-12, and the lateral teeth vary from 3-5.
The comb-teeth arrangement for this species is
3-5 .O. (8-12).0.3-5 (Fig. 2b).
Females of both Ma. dives and Ma. bonneae
were frequently collected in landing collections.
Thus, catches of these mosquitoes were made
in three different places at the study areas in
Keban Agung, Gunung Agung, and in the Field
Station at Cahaya Negeri (Fig. 1). One hundred
female mosquitoes of each Ma. dives and Ma.
bonneae were collected. They were held overnight in plastic cups of not more than 25 specimens in each cup on each collection trip. The
following morning these mosquitoes were killed.
They were then visually sorted out, according
)
'
(a) Ma. bonneae
(b) Ma. dives.
Fig. 2. Showing the comb-teeth of Ma. rnansonia and Ma dives.
..* : ...... ...
... .
detached tooth
SUWARTO, ET. AL.
RESULTS
The results show that the arrangement of the
central teeth count for Ma. bonneae varies with
populations from different areas. In Gunung
Agung, it was 81% with 9 central teeth, Keban
Agung 76% with 10, and Cahaya Negeri 76%
with 11 teeth (Table 1).
Of 300 Ma. bonneae from the three areas
examined, the range of 9-1 1 central teeth count
is common as the average percentage of these
teeth count was 34.3% with 9 teeth, 33.3% with
10, and 27.0% with 11 teeth count. The 8
central teeth count is uncommon being confined to only 5.7% (Table 1). Detached tooth
between the lateral and central teeth group was
found in 99.3% of 300 specimens examined.
AU the specimens examined were found with
4 lateral teeth on each side of the comb.
For Ma. dives the arrangement of the combteeth was found to be fairly consistent between
the populations of three areas. The majority
of them were found with 10 central teeth count.
In Gunung Agung and Cahaya Negeri 80%
and 86% were with 10 central teeth count respectively, and 68% were found in Keban Agung.
Thus, it gives an average of 78% of 300 specimens examined with 10 central teeth (Table 1).
It appears that the species with 10 central
teeth is predominant, with 9 fairly common,
and with 8 or 11 central teeth uncommon in
the areas studied. There was no detached tooth
between the lateral and central teeth rows
Table 1. Percentage of Ma. bonneae and Ma. dives
with different central teeth count from
three areas
Ma. dives
Ma. bonneae
Locality
NO. of central teeth count No. of central teeth count
8
9
10
11
10
11
8
9
3
4
8
86
2
2
5
25
68
2
19
76
6
11
80
3
33.0
27.0
5.0
14.7
78.0
2.3
Gunung Agung 12
81
4
KebanAgung
3
19
76
Cahsya Negeri
2
3
Average
5.7
34.3
_
shown in any of the specimen examined. The
lateral teeth count ranged from 3-5. Of the
300 specimens examined, 92.7% was found
with 4 lateral teeth on each side of the comb,
6.0% with 3 and 1.3% with 5 only.
On visual separation of these two species
by the supra-alar scales, after each of the species
had been examined for the arrangement of
the comb teeth for confirmation, the following
results are obtained and presented in Table 2.
The results show that the reliability of external morphological characteristic identification
in the field was 88.7% for Ma. bonneae and
94.0% for Ma. dives (Table 2).
Table 2. Error (%) by supra-alar scales iden
tification for Ilia. bonneae and Ma.
dives from three areas.
I
Ma. bonrteae
Locality
*
Gunung A g u n g
.
14
1
Ma. dives
7
Agung
10
5
Cahaya Negeri
10
6
Keban
Average
11.3
6 .O
% Accuracy
88.7
94.0
DISCUSSION
The present experiment on field identification
of Ma. bonneaeldives group based on the supraalar scales, and confirmed by examination
of the comb-teeth count on the eighth abdominal
tergite, revealed that 88.7% Ma. bonneae and
94% Ma. dives could be accurately identified.
The reliability of the conventional identification
based on 'the presence of the comb-teeth is
absolute. As there is an overlap in the central
teeth count between both species, thus a more
important characteristic is the lateral teeth
count and the presence or absence of the detached tooth between the lateral and central
teeth rows in the separation of Ma. bonneae
from Ma. dives. Although error is unavoidable
by routine field examination of these mosquitoes
by the presence or absence of the supra-alar
FIELD IDENTIFICATION OF MANSONIA BONNEAE AND MANSONIA DIVES
scales, in areas when the population of these
mosquitoes are high, it would be impractical
to examine the comb-teeth count for confirmation of the species. In such situations, it may
be necessary that assessment of errors in the
identification based on visual separation by
both the presence or absence of the supra-alar
scales and count of the comb-teeth as the standard should be carried out initially as a baseline quantification.
The importance of Ma. bonneae and Ma.
dives as vectors of both forms of brugian filariasis is well documented (Lie, 1970; Wharton,
1962; Turner & Edeson, 1957; Suzuki et al.,
1981). In addition, both these species were
shown to be susceptible to Bmgia pahangi
and Dirofilaria spp. (Wharton, 1962). In our
study areas at Bengkulu, periodic B. malayi
is prevalent among the human inhabitants,
B. pahangi is common among domestic cats
(Felis cattus) and also found in a species of
carnivore (Paguma lawatus), and Dirofilaria
magizilawatum is prevalent among the nonhuman primates, Macaca fascintlaris and Presbytis cristata. It is therefore quite possible
that these mosquitoes could also be parasitized by different kinds of non-human filaria
worms. Therefore, in studying the vectorial
capacity of any of these parasites, reliable
identification of these mosquitoes is.
critical. Careful attention must also
be given when using field caught mosquitoes
of these two species for laboratoly experiments.
SUMMARY
The reliability of using external morphology
by examining the presence or absence of supraalar scales, in separating Mansonia bonneae
from Ma. dives was assessed and compared with
that using the arrangement of the comb-teeth
on the eighth abdominal tergite. It was estimated that a probability of 11 3%and 6% errors
respectively were present in the identification
of Ma. bonneae and Ma. dives on the basis
of external morphology, if comb-teeth arrangement was used as the standard.
ACKNOWLEDGEMENTS
The authors are grateful t o the field staff,
National Institute of Health Research and
Development, Jakarta and Provincial Health
Services, Bengkulu, Sumatera for their assistance
in collecting mosquitoes. To Dr E. Oswari,
Director of Health Services, Bengkulu, Dr Abu
Hanifah, Chief, CDC/Bengkulu, for their supports.
They also wish to thank Dr N.G. Gratz, Director, VBC, Geneva, Dr C.P. Pant, Chief,
ECV, Geneva for their comments, and also to
Dr Y.H. Bang, Project Leader, VBCRU-2,
Jakarta for his support.
REFERENCES
Lie, K J . (1970) The distribution of fdariasis
in Indonesia. Southeast Asian J. Trop. Med.
Publ. Hlth. 1 :366-376.
Suzuki, T., M. Sudomo, Y.H. Bang and Lim Boo
Liat (1981) Studies on malayan fdariasis
in Bengkulu (Sumatera), Indonesia with
special reference to vector confirmation.
Southeast Asian J. Trop. Med. &bl. Hlth. 12 :
47-54.
Turner, L.H. & J.F.B. Edeson (1957) Studies
on fdariasis in Malaya : The periodicity of
the microfdariae . of Wuchereria malayi.
Ann. Trop. Med. Parasitol. 51 271 -277.
Wharton, R.H. (1962) The biology of Mansonia
lnosquitoes in relation to the transmission
of fdariasis in Malaysia. Institute Med. Res.
Bull. 11 : 114 p. (Revised edition).