ICMR BULLETIN VOL.6-No.-8-AUGUST-1976
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- ICMR BULLETIN VOL.6-No.-8-AUGUST-1976
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COMMUNITY HEALTH CELL
V°L 6 No. 8
326, V Main； I Block
August, 1976
Koramangala
Bangalore-560034
•
India
RESEARCH
ON
Malaria, filariasis and several viral in
fections are some of the diseases transmitted
by mosquitoes and the control of these is of
prime importance.
For
over two decades,
vector control programmes have relied largely
upon organochlorine and organophosphate in
secticides . This is now threatened by the in
creasing resistance
of vector species to
available insecticides, the scarcity of new
alternative insecticides, the increased cost
of the major chemical insecticides which are
petroleum derivatives
and the
hazard of
environmental pollution that the use of some
of these compounds produce.
To test the
feasibility of genetic control techniques in
controlling
or eradicating mosquito popu
lation, several field trials were conducted,
using chemosterilized male releases, on Culex
fatigans populations in Delhi villages in
1970.
Even though' high degrees of sterility
in the mosquito population could be achieved,
mosquito control was not possible mainly on
account of the biological factors viz. exten
sive breeding, widespread migration and high
reproductive
potential.
The
experiments
showed that it may not be possible to control
C. fatigans by genetic methods alone in the
environmental' conditions existing in India
where they are not found as isolated * popu
lations.
Genetic
control
methods
for
Anopheles s七ephenst are not available due to
several reasons, viz. (a) suitable methodology
to study the species is not available, (b)
mass rearing of the species and its sexing
have not yet been achieved, and (c) there is
no genetic system, at present, which can be
put into operational use.
VECTOR
CONTROL
In view of the immediate and long term
needs of the country, a centre for Vector
Control Research was established at Pondi
cherry in 1975.
The objectives of the Centre
are to carry out research on all methods of
control of arthropods of public health impor
tance, which include insecticidal, biological
(including genetic and microbial) and environ
mental control and also to study certain
hitherto unknown aspects in the epidemiology
of the two important mosquito-borne diseases
viz. malaria and filariasis:
The results of
some of these studies are highlighted below:
VECTOR ECOLOGY:
Of the three major vectors of malaria- in
south India Anopheles cutvcifacies3 Anopheles
fluvzatitvs
and Anopheles stephansZ., the
latter appears to be present in very small
numbers in Pondicherry.
力. stephensi was
found to be breeding in 11.8 per cent to 46.6
per cent of the wells in the town.
Regular
fortnightly surveys of the wells showed that
the average number of pupae per well was low
(0 to 1.20 in different fortnights) indicating
that emergence of adults from wells is ，low.
This was confirmed by trapping newly emerged
adults in emergence traps placed over the
wells.
However, since trap efficiency was
demonstrated to be low, the actual emergence
from wells may be somewhat higher than what
the results indicated.
Intensive efforts to develop a methodo
logy for the capture of adult A. stephensi
were generally unsuccessful, probably due to
the low population density of this species in
Pondicherry.
All night collections on human
bait and in cattle sheds were made on 8
occasions in five different localities where
A. stephensi was found breeding. Out of about
4500
Anopheles
collected,
37
were
4. stephensi; one taken on human bait and the
rest in cattle sheds.
BIOLOGICAL CONTROL:
The concept of biologically controlling
obnoxious pests'6f public health importance is
fairly recent.
Many methods of biological °
control of mosquitoes have been advocated and
barring the use of predatory fishes, the other
methods are still in the experimental stage.
Fishes:
Use of fish for mosquito control has been
in operation in many countries and notable
success in malaria control by this means has
been claimed in many countries, chiefly Iran,
Soviet Union and U.S.A.
In Iran, fish has
been successfully used as an auxilary measure
along with other control measures like use of
insecticides;
similar
success
has been
achieved in an experimental pilot study in
India at Hyderabad.
As a result of intensive survey for indi
genous larvicidal fishes in different habitats
in the Pondicherry area, 13 species have so
far been recognised and maintained in the
laboratory. In addition, the Guppy, Poecilia
sp・， has been brought from Madras.
The Guppy
(like Gambusia and Tilapia) though an exotic
species, was introduced in India many decades
ago and is now found in several parts of
India.
The predation efficiency of the different
species of fishes was tested in the laboratory
and showed a range of 10-110 mosquito larvae
per day per fish.
The largest consumers of
larvae were Z. -mossambica (110), Ophiocephalus
sp. (80), G, affinis (66),
and the
Guppy,
PoeciVLa sp. (54). The former two species are
predators in both the juvenile and adult
stages. Their utility in large scale control
measures is limited.
Very little is known
about the biology of the other indigenous
species and these are now being studied to
explore the possibility of mass rearing them.
Salinity tolerance
of 0, melastigmaj
blodhii and G. affinis was tested against
ambient saline solution and the results show
that 。・ melastigma
and
A. blochii have
2
greater
tolerance
for
salinity
than
G. affinis.
But in the environment where
mosquito breeding takes place, G, affinis with
further selection can be expected to survive
better.
In order to select a species of fish for
practical application in mosquito control, the
candidate
fish miist
have the
following
properties(ij it should be a live-bearer
which could be easily mass reared; (ii) it
should be small in size and be able to pene-*
trate easily most mosquito breeding habitats;
(iii) it should feed preferentially on mos
quito
larvae and pupae,
when they
are
available but should be a diverse feeder cap
able of surviving when the ^mosquito larvae are
not available; and (iv) it should have good
tolerance
for variations in
temperature,
salinity and organic waste pollution and for a
large number of chemical larvicides.
• Whereas very little is known about the
potential of the indigenous larvicidal fishes
for practical application, G. affinis seems to
have most of
the
requisite
properties.
However, its tolerance against organic pollu
tion seems to be low. The Guppy (PoedVia sp.)
has been known to tolerate organic pollution,
and at the same time has all the other
qualities of Garnbusza.
In a small scale field trial in Pondi
cherry, 10 wells with mosquito breeding were
selected and 0. melastzgma was introduced into
seven wells. Fifty fishes were introduced in
each well. In the wells where mosquito larval
density was moderate (1,000 to 15,000), the
wells turned completely negative in a week * s
time. In two wells with high mosquito larval
density (150,000 to 500,000) while no absolute
control was achieved, the density decreased
after three weeks (130 to 300,000 respec
tively) .
In these wells thousands of egg
rafts were found on each observation.
It is
possible that the number of fishes introduced
in these wells may not have been adequate. In
wells where no fishes were introduced, the
mosquito larval density actually increased ten
fold.
Further studies are needed for con
clusive results.
Work is now in progress on mass rearing
of G. affinis and Poecilza sp.
for field
releases. Their tolerance to insecticides and
other chemicals is also being investigated.
Insect predators:
Under natural conditions some
species of
aquatic . bugs belonging to the family
Notonectidae suck the sap of mosquito larvae
and kill them.
Three species collected
locally were identified as Anis ope bozaHerij
A.
and Enii^hares ciliata.
Predation
studies in the laboratory showed that
4. bowneri has the potential for being used
as a biological control agent.
It was
observed during field surveys that habitats
whidi contained these bugs in large numbers
had either very few or no mosquito larvae. To
demonstrate the predation efficiency of these
bugs, two cisterns of identical measurements
containing water were set up in the back yard
of the laboratory.
TWo egg rafts of
C・ fatigans were seeded daily in both the
cistems.
A small amount of larval food was
also provided to reduce the mortality.
After
seven days twenty bugs were introduced into
one of the cisterns and daily seeding of egg
rafts continued.
From the cistern with bugs
only 1302 piq)ae were collected as against 3314
pupae from the cistem without bugs.
The ejq)eriment was repeated with the bugs
being introduced on the day of seeding of egg
rafts. A daily seeding of 10 egg rafts was
made in each cistern, with ten bugs in one of
them.
The bugs were observed to attack the
rafts and many eggs disintegrating from the
rafts sank to the bottom. The predator action
of the bugs was greater on the egg rafts than
on the larvae. Although in an environment in,
fested heavily with larvae, the bugs could
reduce the population of larvae, their inportance lies in the prevention of hatching of
egg rafts.
During the 25 days of observation 2853
pupae were recovered from the cistern which
had no bugs, whereas not a single pupa was
produced in the cistem which had bugs,
inspite of a daily seeding of 10 egg rafts.
Laboratory studies on the biology of the bugs
showed that their life cycle extends for about
35 days and that each of the five stages of
nymphs predate on mosquito larvae.
Further
studies on the biology of this species, in an
attempt to mass rear them, are in progress.
Larvae of Culex (Lutzza) sp. predate on
mosquito larvae in nature and are one of the
chief factors responsible for their mortality
in certain h曲itats.
Attempts are being made
to colonize the predator species from wild
collected larvae and pupae.
Simultaneously,
studies are also being conducted on the bio
logy and predation efficiency of these
species.
Laboratory studies showed that one
fourth instar larva of Lutzia has the capacity
to predate on 20-25 fourth instar larvae of
C, fatigans in one day.
Microbial agents:
(i) Surveys:
公 randomised sample survey has been
undertaken in and around Pondi cherry to deter
mine the incidence of parasites and other
pathogens in mosquito larvae.
Paddy fields,
ponds and ditches have been searched in four
localities so far. In three of these, mosquito
larvae infected with a fungus resembl
ing Coelomomy8s sp. have been found and
others infected with nematodes
(probably
mermethids) have been found in all the four
localities.
In paddy fields, both AnopheIes
(A, Subpzetus and A. vagus)
and Culex
C visknui) larvae have been found infected
with fungus.
A high proportion of the larvae
examined were infected with fungus (246 out of
627 Anopheles larvae and 62 out of 181 Culex
larvae).
Anopheles larvae infected with
nematodes have also been found in ditches and
in a cement tank. 6 of 68 Anopheles larvae,
(probably A, step%©九s，) from urban wells were
infected with fungus.
In certain paddy fields, the infection
seems to be heavy.
Mosquito larvae collected
from such localities show infection as high as
50 per cent for fungus
and 80 per cent
for nematodes.
(ii) Microbial agents from mosquito larvae:
Fungus infected mosquito larvae were
easily detected in nature by their charac
teristic rusty appearance and were found to be
full of sporangia in different stages of matu
ration and in some instances the mycelium
could be observed. In the laboratory, the in
fected larvae generally died before pupation,
indicating that the fungus was lethal.
How
ever, one of the several adult mosquitoes
examined . in the laboratory showed sporangia
indicating that very rarely a few infected
larvae do pupate and become adults.
Germi
nation of sporangia resulting in the libera
tion of zoospores was observed. This has been
found to be one of the important methods of
dissemination of the pathogens in nature. The
infected larvae could be stored at 5°C on wet
filter paper. Germination was observed in the
stored specimens also.
The stored materials
were observed periodically to determine
whether they remained viable under the condi
tions of storage.
The size,
shape and
markings on the sporangia and the nature of
3
the mycelium of the fungus infecting Anopheles
sp. and Culex sp. appear different suggesting
that there are
two different species of
fungi.
The nature of
mycelium and the
sporangium, the appearance of the infected
host and the method of germination of the
sporangium indicate that the fungus belongs
to Coelomornyces sp.
Studies are in progress
to standardize the method for mass culturing
of this fungus.
Mostly third and fourth instar mosquito
larvae were found infested with nematodes.
Generally one or two, and in rare instances
four worms were found in the haemocoel.
The
infested larvae under laboratory conditions
did not pupate and invariably died.
The
actual emergence of the nematode and the
oozing out
of the haemolymph were
also
observed.
This has been reported to be the
cause of death in nematode-infested larvae.
Examination of naturally occurring pupae did
not reveal the presence of the nematode.
The lack of pupation of the infested
larvae and emergence of the nematode resulting
in the death of the host would indicate that
the nematode observed is a parasite probably
belonging to mermethidae.
Two bacterial agents have been isolated
from a sick Anopheles larva.
Preliminary
studies indicate that they are lethal to the
mosquito larvae.
Experiments are in progress
to determine their pathogenicity to other
species of mosquitoes.
MOSQUITO COLONIZATION:
Rearing:
Colonies of C. fatigans (Pondicherry and
Delhi strains) and A. stephensi type main
tained in the laboratory have the capacity for
production of upto 10,000 larvae/day.
The
number can be increased if required.
Separation of male and female A.
stephensi：
Since similar sizes of the pupae in
A, stephensi- larvae have
handicapped the
mechanical separation of males and females
required in a release programme, strains with
small sized male pupae and larger female
pupae, have been obtained by a process of
selection.
This process is still continuing
and is in- the F】。generation at Pondicherry.
Alternatively,
efforts are being made to
select a line in which males pupate a few days
before females.
This selection process is in
the second generation.
4
Colour variations in Iaboratory
C. fatigans and A, stephensi:
colonies
of
Pink, green and brown larvae and pupae of
C. fatigans and brown, green and black larvae
and pupae of A, stephensi have been observed
in normal rearing trays.
By a process of
selection, a green line of C fatigans has
been purified and is now in F12 generation.
Attempts are in progress to purify the other
lines< In A. stephensi3 heavy pupal mortality
was observed consistently in the trays with
green larvae.
The brown and black strains
have been isolated and further selection is
progress for purifying
the strain.
The
selected purified strains, when ready, will be
tested for differences in susceptibility for
malaria
transmission.
Their
biological
characteristics are now under study.
Colonization of 4.
culzcifades'：
It is well known that this important
malaria vector species has not been colonized
in the laboratory so far.
Attempts are.,
therefore, being made to colonize A. cuVictfacies3 the major malaria vector. Probably as
a result of intensive spraying with insecti
cides as part of public health and agri
cultural measures, this species have become
rare even in conventional breeding places like
paddy fields. Extensive collections were made
in pools in Penniar river in Pondicherry and
South Arcot and it was found that less than
0.1 per cent of larvae were A. cuUcifacies.
Attempts are continuing to locate more breed
ing places further upstream, where A. culcifades breeding has been reported.
About 70
specimens have been
obtained so far and
atten^ts are being made to overcome the diffi
culties experienced in mating and oviposition
in the laboratory.
GENETIC STUDIES:
Radi osterilization:
Irradiation of 4・ stephensi with 7 kR
from a cobalt 60 source induced 100 per cent
sterility in the females and 96.5 per cent
sterility in the males. Radiosterilised males
competed favourably in the insemination of
females.
In order to achieve higher male
sterility, pupae were irradiated with 8 kR.
Sterility in males averaged 97.2 per cent with
reduced competition for mating.
Even at a
dose of 10 kR, which is injurious to males,
sterility averaged 99 per cent.
Efforts are,
therefore,
being directed
towards chemo
sterilisation of
4. stephensi
99.9 per cent male sterility.
to
achieve
Culex pipiens fatigans (Prague cytoplasm)
is bidirectionally incompatible with majority
type Delhi strain while with the minority
Delhi type it is unidirectional i.e. females
of Prague cytoplasmic type are compatible with
minority (De 19) type males. The frequency of
De 19 type males varies from one geographical
area to another (Delhi 10-30 per cent,% Ami
50 per cent,
Trivandrum 70 per cent).
At
optimum efficiency, grids can separate males
with 0.3 per cent female contaminants.
These
contaminant females may mate with De 19 males
and establish a new strain in the area of re
lease. Therefore,if the cytoplasmic incompati
bility phenomenon is to be used for population
control, female contaminants should either be
removed or made non-reproductive. This can be
achieved by radiosterilization of the release
material at a dose that would make
the
contaminant females non-reproductive. Experi
mentally it was found that females fail to
oviposit at 4000R, a dose which produces 5060 per cent sterility in the males.
There
fore, radiosterilization of the C. fatigans
(Prague cytoplasmic) at 4000R would ensure
elimination of all reproductive females and
provide extra protection against the possi
bility of the loss of cytoplasmic incompati
bility in males due to aging - a phenomenon
recently observed.
Chemosterilization:
Use of thiotepa to sterilise mosquitoes
as part of an eradication programme in India
was criticised in view of the possibility that
either thiotepa or its breakdown products may
contaminate the food chain components.
This
was substantiated by a research report that
spiders fed on mosquitoes sterilized with
thiotepa had reduced fertility.
Hence it
became necessary to find a method that could
eliminate residues of thiotepa from chemosterilised mosquitoes.
This breakthrough was
achieved by dipping the chemosterilized pupae
in acidic water (pH 2.6-2.8) and then in
alkaline water (pH 9.1-9.4) for 90 minutes
each.
Dipping of pupae in acidic water
ensures breakdown of thiotepa to ethyleneimine
while dipping in alkaline water leads to break
down into non-toxic phosphoric acid compounds.
Residue-free emergent mosquitoes survive well
for atleast 3 weeks and compete favourably
with untreated males in the insemination of
females. Mass release of such males for popu
lation control will not pose the hazards of
environmental contamination.
Mating competitiveness and
city:
insemination capa
Mating jcompetiti veness of
small size
sterile males was tested and compared with
that of mixed size sterile or normal males and
it was found that there was no significant
difference in either the mating competitive
ness or insemination capacity.
Genetics of A.
stephensi:
Inversion
polymorphism:
Cytological
ana
lysis of polytene chromosomes from larval
salivary glands from different geographical
areas in and around Delhi, Bangalore and
Coonoor have exhibited inversion polymorphism.
Five different
pericentic
inversions
in
different arms of the autosomes have been
observed.
The
frequency
and
type
of
inversions vary from stock to stock.
There
appears to be a correlation between egg hatch
and the number of inversions present in any
stock.
This study has been undertaken to
correlatp the presence of a particular in
version to insecticide tolerance and vectorial
susceptibility.
Translocations: One autosomal (R-26) and one
male-linked translocation (R-56) have been
induced
in
a
laboratory
colony
of
4. stephensi.
R-26 translocation
has an
average sterility of 58.3 per cent while the
R-56 translocation shows 70-80 per cent steri
lity. Cytological analysis of the R-56 trans
location revealed that it involves all three
chromosomes.
Mating competitive tests have
shown that R-56 males are equally competitive
with wild males.
High sterility, absence of
crossing over and its mating competitiveness
suggests
that R-56 translocation
has
a
potential value in genetic control.
Geneti cs of Culex pipvens
fatzgans:
Cytoplasmic incompatibility: Experiments have
been designed to obtain direct evidence for
rickettsial involvement in the phenomenon in
cytoplasmic incompatibility.
An equal number
of larvae from aposymbiotic line (obtained by
treating the larvae with tetracycline and is
free of rickettsiae) and from De ru/ru (Delhi
cytoplasmic and ruby-eye marker) were cultured
together for several generations. If rickett
sial organisms can pass from one organism to
another it is possible that
aposymbiotic
larvae can get reinfected with rickettsiae
from ru/ru larvae during larval development.
Appropriate genetic crosses have shown that
there is no change in the cytoplasmic proper
5
ties of aposynibiotic line.
Electron micro
scopic studies are in progress to see whether
rickettsial organisms have reinfected
the
aposynibiotic line.
Male-linked trans locations: Five male linked
translocations are available.
Three of the
translocation lines are being maintained as
selected and unselected lines with 70-80 per
cent and 50-60 per cent sterility
levels
respectively. Cytological analysis of meiotic
chromosomes from pupal tests has shown that
both selected and unselected lines carry a
single translocation involving sex chromosome
and an autosome.
This suggests that the
difference in sterility level between selected
and unselected lines is not due
to the
difference in the number of translocation
complexes but it may be due to recessive
lethals present in selected lines which are
being carried from one generation to another
because of the
selection procedure.
In
addition, cytological analysis has confirmed
the genetic studies carried out with the
translocation lines using an autosomal marker
in establishing which of the two autosomes is
involved in each translocation.
One trans
location D 371 involves all three chromosomes
and thus exhibits higher sterility (70-80 per
cent) without any selection procedure.
Autosomal translocations:
Eight
autosomal
translocations have been induced for various
genetic studies.
Females from three trans
location lines were crossed with males from a
male linked translocation to obtain double
translocation
heterozygotes involving
all
three chromosomes.
Out of three such double
translocation heterozygotes one line has shown
77.2 per cent sterility and this， appears to
offer a potential measure for genetic control
programme. In addition, by crossing males and
females from different translocation lines
double .translocation heterozygotes involving
only two chromosomes were obtained but their
sterility levels when crossed with wild type
were much lower than the double translocation
heterozygotes involving all three chromosomes.
Autosomal translocation lines are cytologi
cal ly being screened to select translocations
with specific break points for use in the
synthesis of compound chromosome.
Phenotypic markers: One larval colour mutant
green larva has been isolated in a laboratory
stock. Genetic studies have shown that it is
a recessive gene and has been mapped on
chromosome 3.
6
STUDIES ON FILARIASIS:
Considerable work on filariasis has been
done in India during the last 25 years in an
attempt to determine the extent of the problem
and to control and prevent the disease.
But,
very little attention has been paid to the
study of the parasite and the understanding of
the disease process.
It has been suggested
that several thousand infective bites are
necessary over a period of time to produce one
new case with circulating microfilariae.
Infection and disease in filariasis are
generally assumed to be a function of the
intensity. of the transmission in an area.
Therefore, to characterise the dynamics of
transmission,
several field studies
were
undertaken in the Pondicherry area, with the
active co-operation
of the local
health
department.
Night blood surveys:
Blood samples collected from residents of
8 localities of Pondicherry were examined for
microfilaria. Of a total of 795 blood samples
collected, 157 (19.7 per cent) were positive
for microfilariae, indicating that approxi
mately every one person in five circulated
microfilariae in his blood.
The mean microfilaria density (number of microfilariae per
20 c.mm. of blood)
in various localities
ranged between 12.5 and 53.5, with an average
of 27.4. The number of microfilariae per in
fected
individual
ranged
from 1 to 359.
Individuals of all ages and sex groups circu
lated microfilariae.
Contrary to reports
published so far, even old people (aged above
60 years) circulated high numbers (more than
100) of microfilariae.
Only 18 people (2.25
per cent of the sample surveyed) had clinical
manifestations
like elephantiasis
of the
limbs.
None of them had microfilariae in
their blood.
It is recognised that the data
on filarial infection among the population
obtained in night blood surveys may apply to
entirely different phases of infection and
may reflect the individual differences in
response to infection.
Studies have been
undertaken to correlate, with the help of a
questionnaire prepared for this purpose, the
disease and infection rates on the one hand,
to the habits, socioeconomic status, period
of stay in known endemic area, etc. on the
other.
Vector density:
Density of indoor resting C. fatigans
females was routinely measured in 5 localities
of Pondicherry. The relative density (number
per man hour) varied from one locality .to
another, but on the whole, it was high, (rang
ing from 25 to 61). Seasonal variation in the
density was seen: in the monsoon months (July
to November) it was comparatively lower than
in
the post-monsoon months
(December to
March).
The mean maximum temperature ranged
between 27°C and 33°C and the minimum between
19°C and 25OC.
The relative humidity varied
between 64 per cent' and 85 per cent?
At
fortnightly
intervals
all night
collection of C. fatzgans biting man was
carried out. The biting intensity was highest
between 11 p.m. and 4 a.m.
The number
of
female C. fatzgans biting a man in one night
ranged between 154 (in the rainy months of
November) and 454 (in the first fortnight of
March.
Infection and infectivity rates in C.
for W. bancrofti:
fatzgans
Because of
the high rate
of microfilaraemia in the population at Pondicherry,
as revealed by the surveys (19.7 per cent) the
infection rate and infectivity rates
for
filarial larvae in the vector population were
routinely assessed.
For this purpose, fed,
semi gravid
and
gravid
mosquitoes
of
C.
fatzgans
collected
in
houses
were
dissected.
The infection rate (number of
mosquitoes with all stages of.filarial larvae/
total number of mosquitoes dissected) ranged
between 1 per cent to 13.5 per cent.
The in
fectivity rate (number of mosquitoes with the
infective
stage of filarial
larvae total
number of mosquitoes dissected) ranged between
0 per cent to 3.5 per cent.
There werevariations in the rates observed in different
months and in different localities.
Experimental transmission studies:
The wild population of C. fatigans has
been found to be a mixture of several types
characterise：d by the colour of larvae e.g.
black, green and brown.
Apart from this
species, the other major man-biting mosquitoes
at night
in this
area are
anophelines
C. tritaenzorhynchus3 and Armigeres dbturbans.
The green strain of C. fatzgans has been puri
fied and is now in the twelfth generation.
Vectorial susceptibility studies were con
ducted with 4・ stephens" C. tritaentorhynchus
and the green C. fatigans strain. Preliminary
results show that while the green strain of
C. fatigans is an excellent vector, both
A. stephensi and C. tritaentoWtynchus are poor
ones.
Laboratory
bred
C. fatigans and
d. tritaeniorhunchus were fed on donors with a
mean
microfilariae count
of 180/20 c.mm.
While the infective stage of the larvae deve
loped in C, fatigans on the 10th day and were
found in th.e\.head from the 11th day onwards,
in C. tritaem^orlrynchus, the microfilariae did
not develop beyond the first stage, and that
too only in a few mosquitoes.
In most of the
mosquitoes, the microfilariae were found dead.
In the case of A. Stephens乞 also the micro
filariae did not develop beyond the first
stage in some mosquitoes and in one mosquito
upto the second stage.
No infective stages
were found. There was also heavy mortality of
A. stephensi.
The experiments are being
repeated.
Armigeres obturbans has been incriminated
in the transmission of
Setarza digitata for
which bovines are the definitive .hosts.
A
colony of this mosquito is being established
for
studying
its
susceptibility
for
忆 bancrofti.
Studies have been
initiated on
the
comparative
susceptibility
of normal and
genetically manipulated
strains
of Aedes
in Dirofilaria. infection.
Results of
Xhis study revealed
that sterilisation of
pupae and adults (before a blood meal) had no
effect on the vectorial potential of. the
females.
However, adult sterilisation after
blood meal resulted in complete inhibition
of
the growth of parasites.
Therefore,
release of contaminated females may not be
hazardous in terms of the vectorial potential.
Attempts
to select a
refracti ve to Deriodic
C. fatigans
bancrofti;
strain of
It has been shown in the case of Aedes
aegypti that genetic factors influence the
susceptibility to infection with the filarial
parasite, Brugta maLaoi.
It has also been
demonstrated with
V. bancroftz that
the
susceptibility can either be increased or
decreased by a process of selection.
In the
event of eradication of
C. fatigans
by
genetic control or any other method, the eco
logical niche will have to be filled
by
another mosquito.
Hence, the possibility of
replacement of a vector strain by a non
vector strain has been suggested.
Attempts
are, therefore, being made to. select a strain
refractory to filaria transmission.
Initially four batches of mosquitoes were
fed on donors with varying microfilaria density.
Fed mosquitoes were individually tubed
7
for egg laying and further dissection. It was
found that presence of microfilaria adversely
affected the
physiology and survival of
mosquitoes.
The normal time taken for deve
lopment of infective stage of microfilaria is
11 to 14 days. If the mosquito laid its eggs
before this period, it could be dissected and
examined for the presence of microfilariae.
But in most cases, even under controlled cli
matic
conditions
(temperature
28°C±1°C,
relative humidity 80 to 85 per cent,
the
mosquitoes fed on donors did not lay eggs for
as'long as 38 days.
However, in a few lines
which were found negative their progeny were
reared and fed • on donors.
In subsequent
generations, because of inbreeding depression
due to brother-sister matings, high larval
mortality was observed. From the four batches
of mosquitoes in the parental generation, 251
mosquitoes which had laid eggs were dissected
and 28 negative lines were
obtained and
pursued in the next generation.
Many of the
mosquitoes also laid unembryonated eggs.
At
present only. 3 negative lines are available
and they are in Fq generation.
Apart from delayed egg laying and high
larval mortality, the fecundity was also low.
Experiments have been planned to overcome some
of the problems caused by the effect of micro
filariae on the mosquitoes.
By feeding the
lines once on chicken blood before feeding on
the
donor it is hoped to
increase the
fecundity and by pooling the negative lines of
the same generation it is expected to overcome
the problem of inbreeding depression caused by
brother-sister matings.
Attempts are also
being made to select strains from localities
with very low filaria endemicity and low or
no
infection and
infectivity
rates
in
mosquitoes.
ABSTRACTS
Some Research Projects completed in 1975
OCCUPATIONAL HEALTH:
A study o了 cardio-respiratory
scissor makers at Meerut
status
of
A total of 175 scissor makers
(100
grinders and 75 non-grinders)
working in
different
scissor manufacturing units
of
Meerut, were studied for their cardio-respiratory status.
None of the non-grinders had
radiological evidence of silicosis whereas out
of the 100 grinders, 55 showed pulmonary sili
cosis .
Of the 55 grinders with silicosis,
stage I (prenodular) changes were present in
3, Stage II (nodular) changes in 29 and stage
III changes in 23 cases.
Three of them had
associated tuberculosis (silico-tuberculosis) .
Incidence of silicosis increased with the
duration of exposure.
A direct correlation
was observed between the incidence of sili
cosis and time intensity factor i.e. dust
count multiplied by number of years of
exposure.
All grinders with time intensity
factor (T.I.F.) above 3000 had radiological
evidence of silicosis.
Further,
stage III
massive shadow or massive fibrosis silicosis
was observed in the majority of grinders
whose T.I.F. was above 2000. The average dust
count in various scissor grinding units ranged
from 26 to 193.6 million particles per cubic
foot of air with a mean of 112 mpef.
The
size of majority of particles was less than 5
8
microns and concentration
of free
silica
ranged from 23 - 37 per cent with a mean
of 31.8 per cent.
Greater reduction
of
vital capacity was observed in grinders with
stage III silicosis as compared to those
showing
stage I and stage II radiological
changes. Twelve out of 55 grinders with sili
cosis showed evidence of right ventricular
and/or right atrial hypertrophy,of whom 9 had
stage III silicosis.
No E.C.G. abnormality
was detected in non-grinders and grinders with
stage I silicosis.
H.S. Mittal
L.L.R.M. Medical College
Meerut.
CARDIOVASCULAR DISEASES:
Effect of Bengal gram an
saccharide content of aorta
acid mucopoly
The data obtained from the study on 120
rabbits confirmed earlier observations that
Bengal gram
supplementation
of the diet
resulted in regression of egg-yolk induced
experimental atherosclerosis in rabbits. This
effect was similar to that produced by oestro
gen injections and was observed in both male
and female animals.
The glycosaminoglycan
(GAG) content of aortic tissue was found to be
increased in egg-yolk fed rabbits as the
atheros cleroti c process progressed, but in
both Bengal gram supplemented and oestrogen
treated groups GAG accumulation decreased. It
is possible that the lipodiatic activity
of
Bengal gram was due to its isoflavone Biochemin A, which is similar to oestrogen in
its molecular configuration.
卜
cases also penetrating keratoplasty
gave
better results than lamellar keratoplasty.
Gurbax Singh
Deptt. of Ophthalmology,
Maulana Azad Medical College
New Delhi.
GASTROENTEROLOGY:
Tissue lipid storage was also decreased
in the groups treated with Bengal gram and
oestrogen.
Another interesting finding was
the nodular lipid storage in the spleen seen
in oestrogen treated female rabbits.
These
nodules became smaller and
fewer 3 months
after withdrawal of the oestrogen treatment.
The- exact relationship between oestrogen and
the nodular lipid storage in the spleen was
not clear.
M. Madhavan
Associate Prof, of Pathology
Jawaharlal Nehru Institute
of Postgraduate Medical
Education & Research
Pondicherry.
OPHTHALMOLOGY:
Therapeutic value
chemical bums
of
comeaL
grafting
in
Experimental studies were carried out on
rabbits to evaluate the role of keratoplasty
in alkali bums of the cornea.
Both general
and local comeal bums with varying degrees
of severity, were produced.
When the damage to the cornea was general
and superficial (Grade I),conservative therapy
gave excellant results.
When the damage
resulted in a hazy cornea, but iris details
were visible (Grade II), the eyes could be
saved with medical or surgical measures.
The
best results were obtained with penetrating
keratoplasty, specially when performed within
24 hours of the injury.
When the result of the damage was a hazy
cornea and iris details were invisible (Grade
III),- medical therapy gave poor results.
Surgical treatment gave good results if per
formed within 24 hours, penetrating kerato
plasty yielding better results than lamellar
keratoplasty.
When the cornea following damage became
totally opaque (Grade IV), medical therapy led
to perforation and loss of eyes.
In these
Diagnostic serum monoamine oxidase 乞九 portal
hypertension
A study was undertaken to ascertain the
value of serum Monoamine Oxidase (MAO) levels
in differentiating portal hypertension result
ing from postnecrotic cirrhosis, non cirrhotic
portal fibrosis, extrahepatic portal hyper
tension and Budd-Chiari syndrome.
Serum MAO levels were estimated in 134
individuals-35 normal subjects,
61 patients
with portal hypertension, 18 patients with
congestive
cardiac
failure
and 20 with
diseases , other than portal hypertension and
congestive cardiac failure and a correlation
was attempted with liver function tests and
hepatic sinusoidal pressure.
It was found
that in quite a few cases of cirrhosis of the
liver, Budd-Chiari syndrome and
congestive
cardiac failure the serum MAO levels were
elevated.
In the cirrhotics there was a
significant correlation of the MAO levels with
the hepatic sinusoidal pressure and the serum
bilirubin levels.
The serum MAO levels were not elevated in
cases of presinusoidal hypertension (extra
hepatic portal hypertension and non-cirrhotic
portal fibrosis), though there was some over
lap with values in the cirrhotics, BuddChiari Syndrome patients and patients of con
gestive cardiac failure. Hence, its value in
the differential diagnosis of pre and post
sinusoidal portal hypertension is limited.
However, estimation of serum MAO, when com
bined with other tests, may help in identi
fying the cause of portal hypertension.
R. Nath
Asstt. Prof, of Biochemistry
Postgraduate Institute of
Medical Education & Research
Chandigarh.
Publication:
Borthakur, P.C., Nath, R., Chuttanni, P.N. and
Datta, D.V. (1974). Serum monoamine oxidase in
portal hypertension.
Indian J. Med. Hes. 61:
1965.
9
ICMR
NATIONAL INSTITUTE OF NUTRITION, HYDERABAD
The
Scientific Advisory Committee of the
National Institute of Nutrition (NIN), met at
NIN, Hyderabad, on the 26th and 27th July,
1976.
The Scientific Advisory Conunittee of the Food
and Drug Toxicology Centre and the Scientific
Advisory Committee of the Laboratory Animal
Information Service (LAIS) Centre, met at NIN,
Hyderabad, on 28th July, 1976.
Dr. S.G. Srikantia, Director, NIN, Hyderabad,
attended the meeting of the ICRISAT/CIMMYT/
UNDP/FAO Policy Advisory Council at Mexico
from 3rd to 7th August, 1976.
INSTITUTE FOR
BOMBAY
NEWS
cipated in the sixth International Congress of
the Primatological Society held at Cambridge,
U.K., from 23rd to 27th August, 1976.
BLOOD GROUP REFERENCE CENTRE, BOMBAY
The Scientific Advisory Committee meeting of
the Blood Group Reference Centre was held at
Bombay on 12th August, 1976.
VIRUS RESEARCH CENTRE, POONA
The Scientific Advisory Committee meeting of
the Virus Research Centre was held at Poona on
13th August, 1976.
NATIONAL INSTITUTE
AHMEDABAD
OF
OCCUPATIONAL
HEALTH,
RESEARCH IN REPRODUCTION (IRR),
Dr. Karan Singh, Union Minister for Health and
Family Planning, visited the Institute for
Research in Reproduction,Bomb ay,on 7 th August,
1976
The
Scientific Advisory Committee of the
Institute for Research in Reproduction (IRR),
Bombay met on 11th August, 1976.
Dr. Shanta S. Rao, Deputy Director, Institute
for Research in Reproduction, Bombay, parti
The
Scientific Advisory Committee of
National Institute of Occupational Health
at Ahmedabad on 30th August, 1976.
the
met
INSTITUTE OF MEDICAL STATISTICS
Leading Statisticians and Health Adminis
trators of the country met under the Chairman
ship
of Dr. C.R. Rao,
Director,
Indian
Statistical Institute, Calcutta, on August 10,
1976 at the ICMR, New Delhi, to discuss the
aims and objectives of the new Institute of
Medical Statistics.
ICMR AIDED SYMPOSIA/SEMINARS/WORKSHOPS
An International Symposium on "Host Virus
Interaction" organised by the Institute of
Medical Sciences, Banaras Hindu University,
Varanasi will be held in October, 1976.
A workshop is being organized on the
•'Role of Paediatricians in the delivery of
health care” at Srinagar in October, 1976.
A Symposium on "Biochemical and Allied
Subjects** is being organised by the National
Institute of Nutrition, Hyderabad from 12th to
14th November, 1976.
A "Second National Symposium on Cryogenics” is being organised by the Indian
Institute of Technology, Madras from 8th to
10th December, 1976.
10
A symposium on "Prophylactic Measures to
Combat Deficiencies of Fat Soluble Vitamins**
is being organised at the Indian Institute of
Sciences, Bangalore,on 10th and 11th December,
1976.
The 9th Annual Conference of the Indian!
Pharmacological Society is being held
at
the Institute of Medical Sciences, Banaras
Hindu University, Varanasi, in December, 1976.
A symposium on “Nutrition, Communicable
Diseases and Priorities of Health Care in
Developing Countries1* will be organised as a
part of the Silver Jubilee Celebrations of
Trivandrum Medical College in December, 1976.
The Silver Jubilee Conference of the
Anatomical Society of India is being held at
the K.G. Medical College, Lucknow, from 29th
December, 1976 to 1st January, 1977.
INDIAN COUNCIL OF MEDICAL RESEARCH
RESEARCH FELLOWSHIPS
Applications are invited
field of bio-medical sciences
for the
following fellowships for research
in
the
1.
Junior Fellowships
Rs.400/- p.m. for
the first year
Rs.450/- p.m. for
the second year
Rs.500/- p.m. for
the third year
M.Sc./M.A./B.D.S.
M.V.Sc., M.S.W., M. Pharma or
C3. Pharma, with three years
research experience, or equi
valent qualifications.
2.
Senior Fellowships
Rs.600/- p.m.
M.B.B.S.,should have completed
internship or M.Sc. with atleast 3 years research ex
perience.
3.
Research Associates
Rs.700/- p.m. to
Rs.1100/- p.m. The
actual value will be
determined on the
basis of qualifi
cations and research
experience.
A doctorate Degree in Medicine
or Science viz. M.D., Ph.D. or
equivalent qualification with
research experience.
The above fellowships will be awarded for specific time bound research projects
to be carried out in the permanent Institutions of the Council, other Biomedical
Research Institutes, Medical Colleges and Universities in the Country.
Full details and application forms obtainable from the Director-General, Indian
Council of Medical Research, Post Box No.4508, Ansari Nagar, New Delhi-110016.
Applications will be received throughout the year.
COUNCIL'S TRAINING PROGRAMMES FOR 1976-77
(A) EXISTING ANNUAL TRAINING COURSES:
(2)
Ninth M.Sc. (Applied Nutrition) Course:
(June 1, 1976 to February 28,1977)
Nutrition and Endocrinology:
At the National Institute of Nutrition,
Hyderabad.
(1)
Annual Certificate Course in Nutrition;
(December 1, 1976 to February 28, 1977)
(3) *Fourth Annual Certificate Course in Human
Nutrition for Teachers in Agricultural
Universities.
(4)
Fifth
Annual
Endocrinological
Training
Course
in
Techniques
and their
11
application: (August 19 to September
1976)
30
Virology:
At the Virus Research Centre, Poona.
Reproductive Biology and Fertility Control:
At the Institute for Research in Repro
duction, Bombay.
(1)
Diploma Course in Virology of Poona
University (July 1, 1976)
CTinical Pharmacology:
Annual Training Course in Reproductive
Endocrinology: (September 15, 1976 to
October 15, 1976)
At the Department of Pharmacology,
G.S. Medical College, Bombay.
A Training Course in Clinical Pharma
cology and Drug Evaluation: (January 15,
1977 to February 28, 1977).
(2) Seventh Annual Training Course in Repro
ductive Biology and Fertility Control:
(November 1, 1976 to February 28, 1977)
(3) Sixth Annual Training Course. on Hormone
Assays: (February 1, 1977 to March 31,
1977)
Seth
(B) NEW TRAINING COURSES DURING 1976-77:
Reproductive Biology and Fertility Control:
Haematology:
At the Institute for Research in Repro
duction, Bombay.
At the Blood Group Reference Centre,
Bombay.
Training Course in Blood Banking and
Basic Haematology for Technicians (February 16, 1976 to May 15, 1976)
Course in Cytology
(September, 1976)
and Cytogenetics:
Occupational Health:
At the National Institute of Occupational
Health, Ahmedabad.
Amoebi asis:
At the School of Tropical Medicine,
cutta.
Technicians
Amoebiasis:
1976)
Cal
Training
Course
on
(April 1, 1976 to June 30,
Biostatistics:
(1)
ICMR/WHO Training Course of Evaluation
and Control of Industrial Environment:
(February 16-28, 1976)
(2) *Training Course on the organizationa of
Occupational
Health Programmes
in
Industry:
Haematology:
At the National Institute of Nutrition,
Hyderabad.
At the Blood Group Reference Centre,
Bombay.
Third Annual Training Course in Bio
statistics for Statisticians and Medical
Research Workers: (September 1976)
A certificate course in Blood Banking
Technology and basic Haematology for
medical Officers for a period of eight
weeks (February 1, 1977 to March 31,
1977).
Animal Technicians Training:
At the Laboratory Animal Information
Service, National Institute of Nutrition,
Hyderabad.
(C) COURSES FOR TALENT SEARCH SCHEME FELLOWS:
Clinical Chemistry and Instrumentation:
Ninth Annual Animal Technicians Training
Course: (September 1,19.76 to November 30,
1976)
12
At the National Institute of Nutrition,
Hyderabad (March 1-10, 1976)
Cell-Biology and Cyto-Genetics:
Inmunological Techniques:
At the Indian Institute of Science,
Bangalore: (April 12-21, 1976)
Principles and Methods in Medical Statistics:
At the Department of Biochemistry, All
India Institute of Medical Sciences,
New Delhi: (January 24, 1977 to Feb
ruary 5, 1977)
At the -Tuberculosis Chemotherapy Centrej
Madras:(December, 1976)
SCIENTIFIC LECTURES TO BE HELD AT
INDIAN COUNCIL OF MEDICAL RESEARCH HEADQUARTERS OFFICE
DURING SEPTEMBER AND OCTOBER, 1976
Date
Topic
Speaker
23.9.1976
Reverse smoking and carcinoma of
hard palate in coastal Andhra
(Sandoz Cancer Research Aurard
Oration)
Dr. C.R.R.M. Reddy,
Visakhapatnam
15.10.1975
Virology in Public Health:
Not an island entire in itself
(Basanti Devi Amir Chand Prize
Oration)
Dr. K.M. Pavri, Poona
29.10.1976
Long term effects of Vasectomy
Dr. Shanta S. Rao, Bombay
ICMR
PUBLICATIONS
TECHNICAL REPORTS
Rs.
Research in Medical Education 1970
4.00
2. Research in Health Practices 197Q
4.00
砌 Acute Encephalopathy Syndrome in Children 1970
4.00
4. Technical Review on Pneumoc oni os is in Indi a彖1970
4.00
5. Exfoliative Cytology 19^L;
4.00
6. Symposium on Nutrition and Heart Disease 19旗
4.00
7. Developments in Industrial Psychology 侬 Indi a
4.00
8僚Study Groiq＞期丽霉加丞制署薛.
4.00
9. Proceedings of Seminar on Immunity and Immunoprophylaxis in Cholera 1971
4.00
1.
13
10. Assessment of the National Filaria Control Programme (India, 1961-70) 1971
4.00
11. Diagnosis and Treatment of Pesticide Poisoning 1971
4.00
12. Symposium on Clinical Evaluation of New Drugs 1972
:4.00
13. Techniques in Blood Group Serology 1972
4^00
14. Laboratory Methods in Investigation of Thyroid Diseases 1972
4.00
17. Proceedings of the First Annual Meeting
4.00
of the Indian Academy of Cytologists 1972
18. Growth and Physical Development of Indian Infants and Children 1972
4.00
19. Review of Work Done in Rural Water Supply in India 1972
4.00
•
20. Genetics and our Health 1972
4.00
21. All India Conference on Research in Reproduction and Fertility 1973
4.00
22. A study of Morbidity Patterns and Standard of Medical Care in the Rural Health
Centres of West Bengal 1973
4,^00
23. Proceedings of the First All-India Workshop Conference on Stroke, 1973
4.00
24. Seminar on Infectious Hepatitis and Study Group on Australia Antigen, 1973
4.00
25. Atlas of Histopathology of Liver: Hepatitis and Cirrhosis, 1974
10.00
26. Studies on Pre-school Children 1974
4.00
27. Studies on Weaning and Supplementary Foods 1974
4.00
SPECIAL REPORTS
1.
Results of Diet Surveys in India 1935-48 (1951) (Special Report No.20)
2.00
2.
Memorandum on the Treatment of Leprosy with Sulphones (1952) (Special Report No.24)
0.37
3.
A Supplement to the Results of Diet in India by K. Mitra (1953)
(Special Report
4.
5.
Review on Haematology with a note on criteria for averages and normals (1953)
tSp嚣妻al Report No.26)
14
l|00^
Treatment and Hygienic Disposal of Lac Wastes by T.R. Bhaskaran (1954) (Special
，Report
6.
1.00
二.二o.62
A review of Work on Indian Medicinal Plants by R.N. Chopra and I.C. Chopra
痴既(施聚遹1 Rep史函曲.
3.00
A review of Work Donq«on Infant Mortality by D.M. Satur and S. Bhatia (1957)
(Special Report No.32)
・
.
1.00
8・
Proteins in Foods by S. Kuppuswamy, M. Sriniwasan and V. Subramanyan (1958)
(Special Report No.33)
2.00
' 9・
Tuberculosis in India: A^ampie Survey, 1955-58 (1959) (Special Report No.34)
2.00
7.
10. Physiological Norms in Indians: Pulmonary Capacities in Health by M.N. Rao,
A. Sen Gupta, P.N. Saha and A. Sita Devi (1961) (Special Report No.38)
3.00
11. Treatment and- Disposal of Sugar Factory Effluents by T.R. Bhaskaran, R.N. Chakraborty,
N. Das and S.N.： Sinha (1961) (Special Report No.39)
1.00
12. 'Nutrition for mother and child by P.S. Venkatachalam and L.M. Rebellow (1962),
2nd Edition 1971 (Special Report No.41)
.
1.50
13. Manual of Standards of Quality for Drinking Water Supplies (1962),
Second Edition 1975 (Special Report Series No.44)
1.00
、
14. Manual of Methods for the Examination of Water Sewage and Industrial Wastes
(1963) (Special Report No.47)
4.5。
15. Utilization of Liquid Wastes from Molasses Distillery for Recovery of Potassium
Salts by R.N. Chakraborty and T. R. Bhaskaran (1964) (Special Report No.49)
0.50
16. Occupational Health Research in India: A Second Review by M.N. Rao and
B.B. Chatterjee (1964) (Special Report No.50)
Gratis
17. Nardostachys jatamansi - A Chemical, Pharmacological and Clinical appraisal by
R.B； Arora (1965) (Special Report No.51)
4.50
18. Dietary Allowances for Indians by C. Gopalan and B.S. Narasinga Rao (1968)
Reprinted in 1974 (Special Report No.60)
4.00
(Available from Division of Pub li pat ion & Information,
Ansari Nagar, New Delhi-110016.
Indian
Council
of Medical
Research,
15
MEDICINAL PLANTS OF INDIA
F
a
The Indian Council of Medical Research' is bringing out a monograph on medicinal
plants of India in two volumes. The monograph presents,for the first time,in a syste
matic way, highlights of researches conducted (between 1960-1972) on medicinal plants.
Thus apart from the botanical (including pharmacognostic), phytochemical,pharmacologi
cal and clinical data, the Monograph presents the Ayurvedic description of the plants
(including synonyms, properties, actions and uses as indicated in various Ayurvedic
.treatises) along with illustrations of the plants.
A glossary of Sanskrit/Ayurvedic
. tqrms has also been incorporated to help the readers.
The Monograph also provides a
Fljst of plants classified, on the basis of their pharmacological properties (indicating
also the active chemical^rinciples, wherever available).
Volume I of the Monograph comprising 350 species of medicinal plants presented in
alphabetical order has just been released.
Volume II featuring another 350 plant
species is under preparation and is likely to be ready for the press by the end of
1976.
Those who are desirous of procuring Volume I of the Monograph (price Rs.30/-.
postage extra) may book in advance as limited number of copies are available.
For
details, contact Chief, Division of Publication and Information, Indian Council of
Medical Research, New Delhi-110016.
EDITORIAL BOARD
Chairman
Dr. C. Gopalan
Director-General
Editor
Dr. G.V； Satyavati
Members
Dr. S.V. Apte
Dr. Usha K. Luthra
Dr. V.N. Rao
Dr. A.D. Taskar
Dr. Sabita Tejuja
Printed and Published by Shri Prem Chand for the Indian Council of Medical
Research, New Delhi at the ICMR Offset Press, New Delhi.
R.N. 21813/71
Position: 2040 (14 views)