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Studies with Brugia pahangi 19. Anthelmintic effects of Mebendazole
546 TRANSACTIONS OF THE ROYAL SOCIETY OF TROPICAL MEDICINE AND HYGIENE, VOL. 72, No. 5, 1978
Studies
with
Brugia
pahangi
19. Anthelmintic
effects
of Mebendazole
D. A. DENHAM, R. R. SUSWILLO AND ROSEMARY ROGERS
Department of Medical Helminthology, London School of Hygiene and Tropical Medicine, Keppel Street, London WClE 7HT Mebendazole is an efficient anthelmintic against intestinal nematodiases (HUTCHINSON et al., 1975). DUKE (1974) found it ineffective against Onchocerca volvulus in a chimpanzee. Since finishing our experiments we have seen an abstract reporting its infections effectiveness in Litomosoides carinii (MCCALL et al., 1975). Despite the fact that very little MBZ is absorbed from the gut and that most of it is excreted in the faeces after administration per OS,it is remarkably efficient in killing encysted Trichinella spiralis when given by stomach intubation (FERNANDO & DENHAM, 1976). This prompted us to examine its activity against Brugia pahangi in vitro and in infected Aedes aegypti, jirds (Meriones unguiculatus) and cats using the methods of ROGERS & DENHAM (1976). The MBZ used was supplied by Janssen Pharmaceutics, Beerse, Belgium.
microfilariae within 24 hours and 40 ppm killed infective larvae in the same time. Two series of observations were made on mosquitoes which had been given an infected blood meal and then fed various dilutions of MBZ in 10% sucrose. At every level at which it was used there was a reduction in the number of infective larvae recovered when the mosquitoes were dissected 11 days after the infective feed (Table I). Eight jirds were given 100 infective larvae each by intraperitoneal injection, three months later six of them were treated with mebendazole at 50 mg/kg body-weight by subcutaneous injection on five successive days. The treated jirds were killed 15, 20 and 30 days after treatment and their adult worms counted (Table II). Even 15 days after treatment most of the adult worms were dead and by 20 and 30 days only single worms were recovered. Eight jirds were infected by implantation of 20 adult worms intraperitoneally (SUSWILLO & DENHAM, 1977). Four of them were treated with
Results Even though it appeared to be insoluble, mebendazole was very active in vitro; 10 ppm killed
Table I-The number of third stage B. pahangi larvae recovered from untreated mosquitoes or from Aedes aegypti fed different levels of mebendazole in loo/6 sucrose after infection. Each group originally contained 30 mosquitoes y0 mebendazole in 10 % sucrose 1 0.5 0.1 0.05 0.01 o-005 0.001 0
Table II-The mebendazole
o/0 mosquitoes
surviving
Run 1
Run 2
3
60 60 15 55 15 70
43 100 100 93
Run 1
Mebendazole-treated
0
0
1.0
: 0.09 0 1.43 0.20 2.35
0.23
from jirds treated with with untreated jirds
5 x 50 mg/kg
Untreated
?
0 1
Run 2
0.93 2.72
number of adult B. pahangi recovered and killed 15 to 30 days later compared
Days of Autopsy
Mean number of larvae per mosquito
A 0
controls
?
25 23
25 7
sc of
D. A. DENHAM
MBZ as in the previous experiment. The treated and untreated jirds were killed 27 and 42 days later and their adult worms counted. No adult worms were found in the treated jirds whereas 16, 18, 18 and 19 were recovered from the untreated controls. Two cats which had been inoculated with 100 larvae into each hind foot three months previously and which had good levels of circulating microfilariae were treated with 50 mg MBZ/kg bodyweight by stomach intubation on five consecutive days. There was no decline in the number of microfilariae in circulation after treatment. The first cat was autopsied 51 days after treatment when a total of 33 female and 16 male worms was recovered (i.e. 24.5 (;.; of the inoculated larvae). The second cat was autopsied 69 days after treatment when 52 females and 29 male worms were recovered (i.e. 40.556 yield). There was no observable effect upon intrauterine embryogenesis. In view of these results the untreated, control, cats were not killed. Two more infected cats were treated with the drug at 100 mg/kg for five days by subcutaneous injection of the drug suspended in l”O Tween 80 in water. No microfilaricidal effect of treatment was noted but within 17 days microfilarial levels were falling and by 25 days the cats were amicrofilaraemic. These two cats were killed 34 davs after treatment and no adult worms were recovered. The control cat gave a yield of 42. I ‘I,. When the treated cats were autopsied, large white deposits were found at the sites where the drug had been injected. There was no inflammation. It is clear that mebendazole is a potent filaricide against B. pahangi in vitro, in mosquitoes and, after injection, in jirds and cats.
et al.
547
Acknowledgements This work was supported by the Ministry of Overseas Development and by the World Health Organization. Rosemary Rogers was supported by the Wellcome Trust.
References Duke, B. 0. L. (1974). Mebendazole-ineffective against Onchocerca volvulus. Transactions of the Royal
Society
of Hygiene
and Tropical
Medicine.
68, 172. Fernando, S. S. E. & Denham, D. A. (1976). The effects of Mebendazole and Fenbendazole on Trichinella spiralis in mice. Journal of Parasitology, 62, 874-876. Hutchinson, J. G. I’., Johnston, N. M., Plevey, M. V. P. & Thangkhiew, I. (1975). Clinical trial of Mebendazole, a broad spectrum anthelmintic, British
Medical
ii, 309-310.
Journal,
McCall, J. W., Crouthamel, H. & Ah, H-S. (1975). Therapeutic and prophylactic activity of Mebendazole against filarial uarasites in iirds. The Associatign
of SoutheasteFn
Biologists,
i2, 64.
Rogers, R & Denham, D A. (1976). Studies with Brugia pahangi. 12. The activity of levamisole. Journal of Helminthology, 50, 21-28. Suswillo, R. R. & Denham, D. A. (1977). A new system of testing for filaricidal activity using transplanted Brugia in the jird. Journel of Parasitology, 63, 591-592.
Accepted
for
publication
10th
April,
1978.
Studies
with
Brugia
pahangi
19. Anthelmintic
effects
of Mebendazole
D. A. DENHAM, R. R. SUSWILLO AND ROSEMARY ROGERS
Department of Medical Helminthology, London School of Hygiene and Tropical Medicine, Keppel Street, London WClE 7HT Mebendazole is an efficient anthelmintic against intestinal nematodiases (HUTCHINSON et al., 1975). DUKE (1974) found it ineffective against Onchocerca volvulus in a chimpanzee. Since finishing our experiments we have seen an abstract reporting its infections effectiveness in Litomosoides carinii (MCCALL et al., 1975). Despite the fact that very little MBZ is absorbed from the gut and that most of it is excreted in the faeces after administration per OS,it is remarkably efficient in killing encysted Trichinella spiralis when given by stomach intubation (FERNANDO & DENHAM, 1976). This prompted us to examine its activity against Brugia pahangi in vitro and in infected Aedes aegypti, jirds (Meriones unguiculatus) and cats using the methods of ROGERS & DENHAM (1976). The MBZ used was supplied by Janssen Pharmaceutics, Beerse, Belgium.
microfilariae within 24 hours and 40 ppm killed infective larvae in the same time. Two series of observations were made on mosquitoes which had been given an infected blood meal and then fed various dilutions of MBZ in 10% sucrose. At every level at which it was used there was a reduction in the number of infective larvae recovered when the mosquitoes were dissected 11 days after the infective feed (Table I). Eight jirds were given 100 infective larvae each by intraperitoneal injection, three months later six of them were treated with mebendazole at 50 mg/kg body-weight by subcutaneous injection on five successive days. The treated jirds were killed 15, 20 and 30 days after treatment and their adult worms counted (Table II). Even 15 days after treatment most of the adult worms were dead and by 20 and 30 days only single worms were recovered. Eight jirds were infected by implantation of 20 adult worms intraperitoneally (SUSWILLO & DENHAM, 1977). Four of them were treated with
Results Even though it appeared to be insoluble, mebendazole was very active in vitro; 10 ppm killed
Table I-The number of third stage B. pahangi larvae recovered from untreated mosquitoes or from Aedes aegypti fed different levels of mebendazole in loo/6 sucrose after infection. Each group originally contained 30 mosquitoes y0 mebendazole in 10 % sucrose 1 0.5 0.1 0.05 0.01 o-005 0.001 0
Table II-The mebendazole
o/0 mosquitoes
surviving
Run 1
Run 2
3
60 60 15 55 15 70
43 100 100 93
Run 1
Mebendazole-treated
0
0
1.0
: 0.09 0 1.43 0.20 2.35
0.23
from jirds treated with with untreated jirds
5 x 50 mg/kg
Untreated
?
0 1
Run 2
0.93 2.72
number of adult B. pahangi recovered and killed 15 to 30 days later compared
Days of Autopsy
Mean number of larvae per mosquito
A 0
controls
?
25 23
25 7
sc of
D. A. DENHAM
MBZ as in the previous experiment. The treated and untreated jirds were killed 27 and 42 days later and their adult worms counted. No adult worms were found in the treated jirds whereas 16, 18, 18 and 19 were recovered from the untreated controls. Two cats which had been inoculated with 100 larvae into each hind foot three months previously and which had good levels of circulating microfilariae were treated with 50 mg MBZ/kg bodyweight by stomach intubation on five consecutive days. There was no decline in the number of microfilariae in circulation after treatment. The first cat was autopsied 51 days after treatment when a total of 33 female and 16 male worms was recovered (i.e. 24.5 (;.; of the inoculated larvae). The second cat was autopsied 69 days after treatment when 52 females and 29 male worms were recovered (i.e. 40.556 yield). There was no observable effect upon intrauterine embryogenesis. In view of these results the untreated, control, cats were not killed. Two more infected cats were treated with the drug at 100 mg/kg for five days by subcutaneous injection of the drug suspended in l”O Tween 80 in water. No microfilaricidal effect of treatment was noted but within 17 days microfilarial levels were falling and by 25 days the cats were amicrofilaraemic. These two cats were killed 34 davs after treatment and no adult worms were recovered. The control cat gave a yield of 42. I ‘I,. When the treated cats were autopsied, large white deposits were found at the sites where the drug had been injected. There was no inflammation. It is clear that mebendazole is a potent filaricide against B. pahangi in vitro, in mosquitoes and, after injection, in jirds and cats.
et al.
547
Acknowledgements This work was supported by the Ministry of Overseas Development and by the World Health Organization. Rosemary Rogers was supported by the Wellcome Trust.
References Duke, B. 0. L. (1974). Mebendazole-ineffective against Onchocerca volvulus. Transactions of the Royal
Society
of Hygiene
and Tropical
Medicine.
68, 172. Fernando, S. S. E. & Denham, D. A. (1976). The effects of Mebendazole and Fenbendazole on Trichinella spiralis in mice. Journal of Parasitology, 62, 874-876. Hutchinson, J. G. I’., Johnston, N. M., Plevey, M. V. P. & Thangkhiew, I. (1975). Clinical trial of Mebendazole, a broad spectrum anthelmintic, British
Medical
ii, 309-310.
Journal,
McCall, J. W., Crouthamel, H. & Ah, H-S. (1975). Therapeutic and prophylactic activity of Mebendazole against filarial uarasites in iirds. The Associatign
of SoutheasteFn
Biologists,
i2, 64.
Rogers, R & Denham, D A. (1976). Studies with Brugia pahangi. 12. The activity of levamisole. Journal of Helminthology, 50, 21-28. Suswillo, R. R. & Denham, D. A. (1977). A new system of testing for filaricidal activity using transplanted Brugia in the jird. Journel of Parasitology, 63, 591-592.
Accepted
for
publication
10th
April,
1978.