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S. A. Ben, M. F. Useh, A comparative study on the efficacy of praziquantel and albendazole in the treatment of urinary schistosomiasis in Adim, Cross River State, Nigeria, International Health, Volume 9, Issue 5, September 2017, Pages 288–293, https://doi.org/10.1093/inthealth/ihx031
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Abstract
Praziquantel (PZQ) is the current drug of choice for the treatment of urinary schistosomiasis in endemic areas. It is very efficacious, although the potential for the development of resistance has been reported in some endemic areas among human subjects and in animal studies. Its’ limitation include high cost and administration of multiple numbers of tablets. Albendazole (ALB) is used in the treatment of intestinal helminths infection. It is a broad-spectrum single-dose antihelminthic with an excellent cure rate and safety criteria. Currently, it is not routinely used for the treatment of urinary schistosomiasis.
Urine samples collected from 596 pupils aged between 2 and 16 years were processed and examined for the presence of ova of Schistosoma haematobium using a standard filtration technique. A total of 100 infected subjects were treated with a standard dose of PZQ (40 mg/kg body weight), while another group of 96 infected subjects were treated with ALB (400 mg for individuals above 3 years). A post-treatment study was conducted 1 month after treatment to assess their cure rate.
The prevalence of S. haematobium infection in the study area was 32.8% (196/596). More males were infected (44.2%) (122/276) than females (23.1%) (74/320). The difference in the prevalence rate of infection by gender was statistically significant (X2=15.7>3.841, p<0.05). The highest prevalence of infection was observed among subjects aged 14–16 years (42.1%) (32/76), while those aged 5–7 years had the least prevalence (23.7%) (38/160). There was no statistically significant difference in the prevalence of urinary schistosomiasis by age of the subjects (X2=5.99<9.5, p>0.05). PZQ gave a higher cure rate of 78.0% (78/100) compared with ALB (68.7%) (66/96). There was no statistically significant difference in the cure rate obtained with both drugs (X2=0.355>0.282, p>0.05). The intensity of egg excretion was greatly reduced in subjects who were not cured by the two drugs.
The findings of this study suggest the use of ALB for the treatment of urinary schistosomiasis. We recommend further assessment of the efficacy of the drug in an area with higher morbidity of urinary schistosomiasis than the present study area.
Introduction
Schistosomiasis is a parasitic disease caused by digenetic trematodes of the family Schistosomatoidae. Five species of Schistosomes are involved in human infection. The three principal agents are Schistosoma mansoni and S. japonicum, which are responsible for intestinal schistosomiasis, and S. haematobium, which is responsible for urinary schistosomiasis. The two other species responsible for intestinal disease, although with low frequency, are S. intercalatum and S. mekongi.1 Snails belonging to Bulinus species are the vectors of S. haematobium.2,3
Urinary schistosomiasis is endemic in Adim, a typical rural rice-farming community in Biase Local Government Area of Cross River state, Nigeria.4,5 Although schistosomiasis is associated with a low mortality rate, it is often a chronic illness that can damage internal organs, and impair growth and cognitive development in children.2 The disease is associated with increased risk for bladder cancer in adults.3 The disease affects about 240 million people worldwide with an estimated 779 million people (more than 10% of the world population) at risk of infection.2 The enormous morbidity associated with schistosomiasis ranks it next to malaria in terms of public health significance, and thus emphasizes the need for a coordinated and sustainable means for the integrated control of the disease.6 This involves chemotherapy, provision of pipe-borne water and elimination of the snail intermediate host among others.
PZQ, a broad spectrum schistosomicide, which is a pyrazinoisoquinoline derivative, is the mainstay and drug of choice for the treatment of schistosomiasis. PZQ has activity against all species of Schistosomes and shows minimal side effects. PZQ is also active against other trematode and cestode infections, though generally not against nematodes. Despite the widespread use of PZQ and nearly after three decades of research, the exact mechanism of action of PZQ is still unresolved. The most obvious and immediate modification that can be observed in Schistosomes exposed to the drug either in vitro or in vivo is a spastic paralysis of the worm musculature. This contraction is accompanied and probably caused by a rapid Ca2+ influx inside the Schistosome. Also widely reported is morphological alterations in the worm tegument, initially represented by vacuolization at the base of the tegumental syncytium and blebbing at the surface.7 These morphological alterations are accompanied by an increased exposure of Schistosome antigens at the parasite surface. Some of the drug-exposed antigens have been identified and appear to be connected with the host immune response that is required for the complete activity of PZQ.8 The recommended dose of PZQ is 40 mg/kg body weight. The drug is available as a 600 mg tablet. The adverse effect of PZQ to organ function is known to reverse to normal 6 months following administration of PZQ. Although it is well tolerated, reported side effects of PZQ includes abdominal discomfort, dizziness, drowsiness, nausea and pyrexia.
ALB is typically a broad-spectrum benzimidazole antiparasitic agent, first approved for human use in 1982. It is useful for the treatment of giardiasis, trichuriasis, filariasis, neurocysticercosis, hydatid disease and ascariasis among others. ALB is an orally administered anthelmintic drug. Chemically, it is composed of methyl 5(propylthio)-2-benzimidazolecarbamate. It is freely soluble in anhydrous formic acid and very slightly soluble in ether and in methylene chloride. Each white to off-white, circular, biconvex, bevel-edged film-coated tablet contains 200 mg of ALB. It causes degenerative alterations in the intestinal cells of the worm by binding to the colchicine-sensitive site of tubulin, thus inhibiting its polymerization or assembly into microtubules. The loss of the cytoplasmic microtubules leads to impaired uptake of glucose by the larval and adult stages of the susceptible parasites, and depletes their glycogen stores.9 Degenerative changes occur in the endoplasmic reticulum, the mitochondria of the germinal layer, and the subsequent release of lysosome.10 The antihelminthic action of ALB is thought to be mainly intra-intestinal. ALB exhibits larvicidal, ovicidal and vermicidal activity, and is thought to act through inhibition of tubulin polymerization. This causes a cascade of metabolic disruption including energy depletion, which immobilizes and kills the susceptible helminths. ALB has been shown to inhibit the enzyme fumarate reductase, which is helminth-specific.11 The side effect of ALB includes abdominal pain, dizziness, headache, fever, nausea and vomiting. There is no published work on the efficacy of ALB against schistosome in this locality.
The aim and objective of the study were to compare the efficacy of PZQ and ALB administered singly for the treatment of S. haematobium infection in this locality with the prospect of replacing PZQ with ALB due to the high cost of PZQ, particularly since the latter is also effective against nematode infections, such as Ascaris and Hookworm disease, which are endemic in this locality.
Methods
Study area
The study was conducted among pupils of Presbysterian Primary School, Adim, Biase, Cross River State, Nigeria, between September and December, 2014. Adim is a typical rural agrarian community that lies between latitude 439, 15.984N and longitude 475, 27.000E. It is located about 110 km to the north of Calabar, the state capital, within the tropical rainforest belt with two major seasons— the rainy (April to September) and dry season (October to March). The major language spoken in the area is Urun. The main occupation of the residents is farming, the principal crops being rice (Oryza sativa), yam (Discorea spp.), cassava (Manihot esculenta) and vegetables. The area lacks a functional pipe-borne water supply.
Ethical approval and consent
The study protocol was reviewed and approved by the Ethical Review Board, Cross River State Ministry of Health, Calabar. Before the commencement of the study, the village head, head-teacher, teachers and parents/guardians were fully briefed on the objectives of the research, procedure, and potential risks and benefits of the study. Thereafter, the guardians and caregivers were given an informed consent form to sign for themselves and their wards. Only children whose guardian signed the consent form participated in the study. The subjects used for this study included school aged children between the ages of 2 and 16 years.
Sample size
The sample size was determined using the formula described by Daniel.12 A urinary schistosomiasis prevalence rate of 29.0% earlier reported by Inyang-Etoh et al.10 for Adim Community was used to calculate the sample size. A total of 596 subjects were involved in the study.
Collection of urine samples
The pupils were randomly selected for screening from grades 1–6. The age, gender and class of each of the pupils selected was recorded, while instructions was given on how to collect urine samples. All the samples were collected between 12.00 hours and 14.00 hours following a brief period of exercise. This period is associated with maximum egg excretion.7 Ten (10 ml) of urine samples were collected from each pupil. The samples were collected before treatment and 1 month post-treatment with PZQ and ALB. Each of the urine samples (10 ml) were preserved by fixing the ova of the parasite in 5 ml of 10% carbol fuschin, before they were transported to the University of Calabar Teaching Hospital laboratory for analysis.
Parasitological analysis and detection of S. haematobium eggs
A mechanical filtration system8 was used to filter each prestained sample of urine using Whatman No.1 filter paper. The prestained specimens were mixed and poured into the filtration unit. The filter paper was carefully transferred to a slide and examined for eggs under a light microscope, with 10× objective with the condenser iris sufficiently closed to give good contrast.
Primary drug administration
Out of the 596 pupils involved in the initial screening, 196 pupils were found urine-positive for S. haematobium eggs. All the 196 egg-positive subjects were divided into two groups of 100 and 96 subjects using a random sampling technique, and were treated with a single oral dose of PZQ (produced by Taj Pharmaceuticals Manufacturing Company, India; 40 mg/kg body weight) and a single dose of ALB (produced by Glaxosmithkline, South Africa; 400 mg for individuals above 3 years), respectively.13,14 The physician who assisted in administration of the drugs also followed-up the reportage of adverse reactions.
Post-treatment evaluation
One month after treatment with PZQ and ALB, the treated pupils were re-screened for the presence of ova of S. haematobium using the same diagnostic procedure employed in the pre-treatment phase.
Data analysis
The SPSS 20.0 (SPSS Inc., Chicago, USA) statistical package was used to analyse the data generated from this study. The prevalence of the infection by age, gender and the parasitological cure rate obtained using the two drugs were compared using χ2 test. The t-test was used to analyse results of intensity of infection. The p–value of less than 0.05 (<0.05), was considered statistically significant.
Results
Table 1 is based on the prevalence of S. haematobium infection among the subjects. Of the 596 pupils initially screened for the presence of ova in their urine, 32.8% (196/596) of pupils were infected. Subjects aged 14–16 years had the highest prevalence (42.1%; 32/76), while those aged 5–7 years had the least prevalence (23.7%; 38/160). There was no statistically significant difference in the prevalence of urinary schistosomiasis by age of the pupils (X2=5.99<9.5, p>0.05). Of the 596 subjects involved in the study, 276 were males, while females were 320. More males 122/276 (44.2%) were infected compared with females 74/320 (23.1%). The difference in the prevalence of infection by gender was statistically significant (p<0.05).
Age (years) . | No. examined . | No.(%) infected . | Mean egg count/10 ml urine . |
---|---|---|---|
2–4 | 40 | 10 (25.0) | 7.0+3.5 |
5–7 | 160 | 38 (23.7) | 9.9+4.9 |
8–10 | 160 | 56 (35.0) | 6.1+3.0 |
11–13 | 160 | 60 (37.5) | 7.0+3.5 |
14–16 | 76 | 32 (42.1) | 7.8+3.9 |
Total | 596 | 196 (32.8) | 7.4+3.7 |
Age (years) . | No. examined . | No.(%) infected . | Mean egg count/10 ml urine . |
---|---|---|---|
2–4 | 40 | 10 (25.0) | 7.0+3.5 |
5–7 | 160 | 38 (23.7) | 9.9+4.9 |
8–10 | 160 | 56 (35.0) | 6.1+3.0 |
11–13 | 160 | 60 (37.5) | 7.0+3.5 |
14–16 | 76 | 32 (42.1) | 7.8+3.9 |
Total | 596 | 196 (32.8) | 7.4+3.7 |
Age (years) . | No. examined . | No.(%) infected . | Mean egg count/10 ml urine . |
---|---|---|---|
2–4 | 40 | 10 (25.0) | 7.0+3.5 |
5–7 | 160 | 38 (23.7) | 9.9+4.9 |
8–10 | 160 | 56 (35.0) | 6.1+3.0 |
11–13 | 160 | 60 (37.5) | 7.0+3.5 |
14–16 | 76 | 32 (42.1) | 7.8+3.9 |
Total | 596 | 196 (32.8) | 7.4+3.7 |
Age (years) . | No. examined . | No.(%) infected . | Mean egg count/10 ml urine . |
---|---|---|---|
2–4 | 40 | 10 (25.0) | 7.0+3.5 |
5–7 | 160 | 38 (23.7) | 9.9+4.9 |
8–10 | 160 | 56 (35.0) | 6.1+3.0 |
11–13 | 160 | 60 (37.5) | 7.0+3.5 |
14–16 | 76 | 32 (42.1) | 7.8+3.9 |
Total | 596 | 196 (32.8) | 7.4+3.7 |
The cure rate obtained following the administration of a single dose of PZQ and ALB is shown on Table 2. The cure rate of 78.0% (78/100) and 68.7% (66/96) were obtained for PZQ and ALB, respectively. The difference in the cure rate obtained between the PZQ- and ALB-treated groups was not statistically significant (X2=0.355>0.282, p>0.05).
Age (years) . | No. treated with PZQ . | No. (%) cured after treatment with PZQ . | No. treated with ALB . | No. (%) cured after treatment with ALB . |
---|---|---|---|---|
2–4 | 6 | 6 (100.0) | 4 | 4 (100.0) |
5–7 | 17 | 14 (70.0) | 20 | 12 (60.0) |
8–10 | 30 | 24 (80.0) | 26 | 16 (61.5) |
11–13 | 30 | 18 (60) | 28 | 22 (78.5) |
14–16 | 17 | 16 (94.1) | 18 | 12 (66.6) |
Total | 100 | 78 (78.0) | 96 | 66 (68.7) |
Age (years) . | No. treated with PZQ . | No. (%) cured after treatment with PZQ . | No. treated with ALB . | No. (%) cured after treatment with ALB . |
---|---|---|---|---|
2–4 | 6 | 6 (100.0) | 4 | 4 (100.0) |
5–7 | 17 | 14 (70.0) | 20 | 12 (60.0) |
8–10 | 30 | 24 (80.0) | 26 | 16 (61.5) |
11–13 | 30 | 18 (60) | 28 | 22 (78.5) |
14–16 | 17 | 16 (94.1) | 18 | 12 (66.6) |
Total | 100 | 78 (78.0) | 96 | 66 (68.7) |
Age (years) . | No. treated with PZQ . | No. (%) cured after treatment with PZQ . | No. treated with ALB . | No. (%) cured after treatment with ALB . |
---|---|---|---|---|
2–4 | 6 | 6 (100.0) | 4 | 4 (100.0) |
5–7 | 17 | 14 (70.0) | 20 | 12 (60.0) |
8–10 | 30 | 24 (80.0) | 26 | 16 (61.5) |
11–13 | 30 | 18 (60) | 28 | 22 (78.5) |
14–16 | 17 | 16 (94.1) | 18 | 12 (66.6) |
Total | 100 | 78 (78.0) | 96 | 66 (68.7) |
Age (years) . | No. treated with PZQ . | No. (%) cured after treatment with PZQ . | No. treated with ALB . | No. (%) cured after treatment with ALB . |
---|---|---|---|---|
2–4 | 6 | 6 (100.0) | 4 | 4 (100.0) |
5–7 | 17 | 14 (70.0) | 20 | 12 (60.0) |
8–10 | 30 | 24 (80.0) | 26 | 16 (61.5) |
11–13 | 30 | 18 (60) | 28 | 22 (78.5) |
14–16 | 17 | 16 (94.1) | 18 | 12 (66.6) |
Total | 100 | 78 (78.0) | 96 | 66 (68.7) |
Table 3 is based on the pre- and post-treatment intensity of infection following treatment with PZQ and ALB. Overall, the difference in the pre- and post-treatment intensity of infection following treatment with PZQ (t=65.78, df=1, t=0.00) and that obtained with ALB (t=24.08) were statistically significant.
Age (years) . | No. treated with PZQ . | Pre-treatment egg count . | Post-treatment egg count . | t-test values . | No. treated with ALB . | Pre-treatment egg count . | Post-treatment egg count . | t-test . |
---|---|---|---|---|---|---|---|---|
2–4 | 6 | 7.0±3.5 | 0 | NA | 4 | 6.0±3.0 | 0 | NA |
5–7 | 17 | 9.9±4.9 | 2.33±1.7 | 6.58 | 20 | 8.2±4.1 | 3.0±1.5 | 5.17 |
8–10 | 30 | 6.1±3.0 | 2.0±1.0 | 11.34 | 26 | 6.3±3.1 | 3.5±1.25 | 6.30 |
11–13 | 30 | 7.0±3.5 | 2.27±1.1 | 12.04 | 28 | 6.2±3.1 | 4.0±2.0 | 9.36 |
14–16 | 17 | 7.8±3.9 | 4.0±2.0 | 13.35 | 18 | 8.6±4.3 | 3.0±1.5 | 6.50 |
Total | 100 | 7.4±3.7 | 2.0±1.2 | 65.78 | 96 | 7.6±3.5 | 2.7±1.3 | 24.08 |
Age (years) . | No. treated with PZQ . | Pre-treatment egg count . | Post-treatment egg count . | t-test values . | No. treated with ALB . | Pre-treatment egg count . | Post-treatment egg count . | t-test . |
---|---|---|---|---|---|---|---|---|
2–4 | 6 | 7.0±3.5 | 0 | NA | 4 | 6.0±3.0 | 0 | NA |
5–7 | 17 | 9.9±4.9 | 2.33±1.7 | 6.58 | 20 | 8.2±4.1 | 3.0±1.5 | 5.17 |
8–10 | 30 | 6.1±3.0 | 2.0±1.0 | 11.34 | 26 | 6.3±3.1 | 3.5±1.25 | 6.30 |
11–13 | 30 | 7.0±3.5 | 2.27±1.1 | 12.04 | 28 | 6.2±3.1 | 4.0±2.0 | 9.36 |
14–16 | 17 | 7.8±3.9 | 4.0±2.0 | 13.35 | 18 | 8.6±4.3 | 3.0±1.5 | 6.50 |
Total | 100 | 7.4±3.7 | 2.0±1.2 | 65.78 | 96 | 7.6±3.5 | 2.7±1.3 | 24.08 |
*The differences between the pre- and post-treatment egg count following treatment with PZQ (t = 65.28, df = 1, t = 0.00) and that obtained with A/B (t = 24.08) were statistically significant.
NA denotes not applicable.
0 denotes no egg count.
Age (years) . | No. treated with PZQ . | Pre-treatment egg count . | Post-treatment egg count . | t-test values . | No. treated with ALB . | Pre-treatment egg count . | Post-treatment egg count . | t-test . |
---|---|---|---|---|---|---|---|---|
2–4 | 6 | 7.0±3.5 | 0 | NA | 4 | 6.0±3.0 | 0 | NA |
5–7 | 17 | 9.9±4.9 | 2.33±1.7 | 6.58 | 20 | 8.2±4.1 | 3.0±1.5 | 5.17 |
8–10 | 30 | 6.1±3.0 | 2.0±1.0 | 11.34 | 26 | 6.3±3.1 | 3.5±1.25 | 6.30 |
11–13 | 30 | 7.0±3.5 | 2.27±1.1 | 12.04 | 28 | 6.2±3.1 | 4.0±2.0 | 9.36 |
14–16 | 17 | 7.8±3.9 | 4.0±2.0 | 13.35 | 18 | 8.6±4.3 | 3.0±1.5 | 6.50 |
Total | 100 | 7.4±3.7 | 2.0±1.2 | 65.78 | 96 | 7.6±3.5 | 2.7±1.3 | 24.08 |
Age (years) . | No. treated with PZQ . | Pre-treatment egg count . | Post-treatment egg count . | t-test values . | No. treated with ALB . | Pre-treatment egg count . | Post-treatment egg count . | t-test . |
---|---|---|---|---|---|---|---|---|
2–4 | 6 | 7.0±3.5 | 0 | NA | 4 | 6.0±3.0 | 0 | NA |
5–7 | 17 | 9.9±4.9 | 2.33±1.7 | 6.58 | 20 | 8.2±4.1 | 3.0±1.5 | 5.17 |
8–10 | 30 | 6.1±3.0 | 2.0±1.0 | 11.34 | 26 | 6.3±3.1 | 3.5±1.25 | 6.30 |
11–13 | 30 | 7.0±3.5 | 2.27±1.1 | 12.04 | 28 | 6.2±3.1 | 4.0±2.0 | 9.36 |
14–16 | 17 | 7.8±3.9 | 4.0±2.0 | 13.35 | 18 | 8.6±4.3 | 3.0±1.5 | 6.50 |
Total | 100 | 7.4±3.7 | 2.0±1.2 | 65.78 | 96 | 7.6±3.5 | 2.7±1.3 | 24.08 |
*The differences between the pre- and post-treatment egg count following treatment with PZQ (t = 65.28, df = 1, t = 0.00) and that obtained with A/B (t = 24.08) were statistically significant.
NA denotes not applicable.
0 denotes no egg count.
Table 4 shows the side effects associated with PZQ and ALB, which includes nausea, pains, dizziness and headache. There was no significant difference at the rate side effects were reported for the two drugs.
Drugs . | No. treated . | No. (%) with dizziness . | No. (%) with nausea . | No. (%) with pain . | No. (%) with headache . | No. (%) with no side effect . |
---|---|---|---|---|---|---|
PZQ | 100 | 10 (10) | 18 (18) | 10 (10) | 9 (9) | 53 (53) |
ALB | 96 | 7 (7.2) | 14 (14.5) | 13 (13.5) | 10 (10.4) | 52 (54.2) |
Total | 196 | 17 (8.7) | 32 (16.3) | 23 (11.7) | 19 (9.6) | 105 (53.5) |
Drugs . | No. treated . | No. (%) with dizziness . | No. (%) with nausea . | No. (%) with pain . | No. (%) with headache . | No. (%) with no side effect . |
---|---|---|---|---|---|---|
PZQ | 100 | 10 (10) | 18 (18) | 10 (10) | 9 (9) | 53 (53) |
ALB | 96 | 7 (7.2) | 14 (14.5) | 13 (13.5) | 10 (10.4) | 52 (54.2) |
Total | 196 | 17 (8.7) | 32 (16.3) | 23 (11.7) | 19 (9.6) | 105 (53.5) |
Drugs . | No. treated . | No. (%) with dizziness . | No. (%) with nausea . | No. (%) with pain . | No. (%) with headache . | No. (%) with no side effect . |
---|---|---|---|---|---|---|
PZQ | 100 | 10 (10) | 18 (18) | 10 (10) | 9 (9) | 53 (53) |
ALB | 96 | 7 (7.2) | 14 (14.5) | 13 (13.5) | 10 (10.4) | 52 (54.2) |
Total | 196 | 17 (8.7) | 32 (16.3) | 23 (11.7) | 19 (9.6) | 105 (53.5) |
Drugs . | No. treated . | No. (%) with dizziness . | No. (%) with nausea . | No. (%) with pain . | No. (%) with headache . | No. (%) with no side effect . |
---|---|---|---|---|---|---|
PZQ | 100 | 10 (10) | 18 (18) | 10 (10) | 9 (9) | 53 (53) |
ALB | 96 | 7 (7.2) | 14 (14.5) | 13 (13.5) | 10 (10.4) | 52 (54.2) |
Total | 196 | 17 (8.7) | 32 (16.3) | 23 (11.7) | 19 (9.6) | 105 (53.5) |
The unit cost of PZQ is $80.56 (₦ 24 168.00) for 1000 tablets and $45 (₦ 13 500.00) for 1000 tablet of ALB. The cost of treating a 20 kg subject with PZQ is $0.0806 (₦ 73.00) and $0.045 (₦ 41.00) for ALB for individuals above three years are as shown on Table 5.
Drugs . | Cost per 1000 tablets in dollars (Naira) . | Cost of treating a 20 kg subject in dollars(Naira) . | Equivalent tablets . | Cost of treating a 40 kg subject in dollars (Naira) . | Equivalent tablets . |
---|---|---|---|---|---|
PZQ | $80.56 (24 168.0) | 0.0806 (73.0) | 1 ½ | 0.1612 (146.0) | 3 |
ALB | $45.0 (13 500.0) | 0.045 (41.0) | 2 | 0.09 (82.0) | 2 |
Drugs . | Cost per 1000 tablets in dollars (Naira) . | Cost of treating a 20 kg subject in dollars(Naira) . | Equivalent tablets . | Cost of treating a 40 kg subject in dollars (Naira) . | Equivalent tablets . |
---|---|---|---|---|---|
PZQ | $80.56 (24 168.0) | 0.0806 (73.0) | 1 ½ | 0.1612 (146.0) | 3 |
ALB | $45.0 (13 500.0) | 0.045 (41.0) | 2 | 0.09 (82.0) | 2 |
Drugs . | Cost per 1000 tablets in dollars (Naira) . | Cost of treating a 20 kg subject in dollars(Naira) . | Equivalent tablets . | Cost of treating a 40 kg subject in dollars (Naira) . | Equivalent tablets . |
---|---|---|---|---|---|
PZQ | $80.56 (24 168.0) | 0.0806 (73.0) | 1 ½ | 0.1612 (146.0) | 3 |
ALB | $45.0 (13 500.0) | 0.045 (41.0) | 2 | 0.09 (82.0) | 2 |
Drugs . | Cost per 1000 tablets in dollars (Naira) . | Cost of treating a 20 kg subject in dollars(Naira) . | Equivalent tablets . | Cost of treating a 40 kg subject in dollars (Naira) . | Equivalent tablets . |
---|---|---|---|---|---|
PZQ | $80.56 (24 168.0) | 0.0806 (73.0) | 1 ½ | 0.1612 (146.0) | 3 |
ALB | $45.0 (13 500.0) | 0.045 (41.0) | 2 | 0.09 (82.0) | 2 |
Discussion
The study confirmed a high prevalence of S. haematobium infection (32.8%; 196/596) among schoolchildren in Adim, Biase L.G.A, Cross River State, Nigeria. In an earlier study, conducted in 1991,6 an endemicity of 43.5% was reported. Thirteen years later, a lower prevalence (29%) was reported among schoolchildren in this community.10 In the continuing absence of an integrated approach for the control of the infection in this locality with emphasis on the provision of clean pipe-borne water and good sanitation, schistosomiasis is likely to remain a serious public health problem in the community. Although government efforts towards the control of the disease lacks coordination and seriousness, children were recently treated with PZQ in the area.
This study is the first in this endemic zone that has assessed the efficacy of ALB vis a vis PZQ for the treatment of urinary schistosomasis. In the present study, PZQ recorded a higher a cure rate (78.0%) (78/100) than ALB (68.7%) (66/96). However, the difference in the cure rate between PZQ and albendazole was not statistically significant (X2=0.355>0.282, p>0.05). Elsewhere, AL-Waili12 reported the cure of two S. haematobium infected subjects with mebendazole, a closely related drug to ALB. In a related study, Katz and Araujo15 did not find any effect of mebendazole upon the quantity and distribution of adult Schistosoma mansoni in experimentally infected mice. Although mebendazole and ALB are effective against cestodes, no proven effect against trematodes have been reported. Therefore, the findings of this study is interesting and require further confirmation in other endemic areas with high morbidity.
Chemotherapy with PZQ currently offers the most feasible means of controlling human schistosomiasis, at least in short term.16–18 PZQ is a broad-spectrum antischistosomal, which is principally active against the adult stage of the schistosome species infective to man. PZQ is known to kill the adult worms and not the immature stages. It is possible that the uncured subjects were habouring the immature stages of the parasite at the point of treatment. The result of this study has shown that PZQ is more efficient in the treatment of urinary schistosomiasis than ALB, although ALB is more readily available and more cost-effective than PZQ.
The intensity of the infection following treatment with the two drugs were greatly reduced among subjects who were not completely cured. It is difficult to assume that those not cured were resistant; perhaps treatment with a higher dose may be needed to resolve the puzzle. The difference in the pre- and post-treatment mean egg count with subjects treated with PZQ (T=13.352) and ALB (df=1, t=0.000) were statistically significant. In a related study, Inyang- Etoh et al.10 reported the combined effect of PZQ and artesunate in the treatment of urinary schistosomiasis in Adim. The cure rates were 72.7% for the PZQ, plus placebo-treated group and 70.5% for the artesunate plus placebo-treated group, while artesunate plus PZQ group had the highest cure rate 88.6%. The cure rate of 78.0% obtained in this study for PZQ is evident that the drug is still efficacious after over 30 years of its usage for the chemotherapy of schistosomiasis.
Control using PZQ is hampered both at individual and community levels by the high cost of the drug [a tin of 1000 tablets of PZQ is sold for $80.56 (₦24 168 in local currency)], whereas the cost of 1000 tablets of ALB is $45.0 (₦13 500.00). The use of PZQ is limited by the high cost that makes it difficult for the majority of the infected people to afford it, particularly in resource-poor settings. It is worth noting that treatment with PZQ is dependent on weight of infected subjects, while ALB has a fixed single dose of 400 mg irrespective of body weight. Thus, cost of treatment with PZQ is further increased.
The frequency of occurrence of side effects that include headache, nausea, pains and dizziness reported by the subjects treated with both drugs were not statistically significant, hence, ALB may be used as a replacement for PZQ.
One of the limitations of the study was the low sample size. Although 596 subjects were screened, only 196 were infected. Enormous financial resources was utilized in establishing diagnosis. Probably a larger sample size would have provided more information. The other limitation is the low intensity of infection of urinary schistosomiasis in the study area; at so low a level the egg excretion is not continuous, and even placebo or drug without effect on the parasite could apparently show a curative effect because a number of individuals positive at baseline, while remaining positive, did not expelled eggs at the time of follow-up. For this reason, it will be essential to study the treatment response to albendazole in an area with high intensity of urinary schistosomiasis infection.
Conclusions
This study has re-confirmed the endemicity of urinary schistosomiasis in the Adim, with a high prevalence of 32.8% among school-aged children. Both PZQ and ALB were efficacious for the treatment of urinary schistosomiasis. Chemotherapy with PZQ and ALB gave a cure rate of 78.0 (78/100) and 68.7% (66/96), respectively, although the difference in the cure rate was not statistically significant. Mild and transient adverse events were observed with both drugs. This study shows the efficacy of ALB for the treatment of urinary schistosomiasis, however, before recommending the use of this drug, additional studies conducted in areas of heavy intensity of infection, should confirm our results. In those settings, the egg output is more stable and the egg reduction rates are more indicative of the drug efficacy.
Authors' contributions: MFU and BSA conceived the study and prepared the protocol for ethical approval. BSA was involved in the fieldwork, as well as analysis of the data generated. MFU and BSA prepared the final manuscript, while MFU supervised the revision.
Acknowledgements: The authors are grateful to participants for their voluntary participation in the study without any of them opting out. The authors are grateful to the head-teacher, teachers and parents of the pupils, and the physician who administered the drugs and reported the occurrence of adverse reactions.
Funding: None declared.
Competing interests: None declared.
Ethical approval: The study was approved by the Ethics Review Board, Cross River State Ministry of Health, Calabar, Nigeria.
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