A preliminary analysis of Wuchereria bancrofti microfilarial antigens for potential use in diagnosis

Several antigens from the microfilarial stage of Wuchereria bancrofti have been identified using immunoblots of microfilarial antigens and screening with immune sera and tropical pulmonary eosinophilia (TPE) sera. This analysis revealed an array of antigens with apparent molecular weights of 14kDa, 35kDa, 42kDa, 63kDa, 88kDa, 97kDa and 200kDa. Among these only the 14kDa and 42kDa antigens were consistently recognized by most of the immune sera. A 132kDa antigen was recognized only by TPE sera. Analysis of rabbit immune sera revealed that the 42kDa antigen was shared by two developmental stages of W. bancrofti, namely L3 and mF. This antigen could become a potential vaccine candidate. The 14kDa antigen seems specific for the microfilarial stage and therefore could be a diagnostic marker for active infection. The 132kDa antigen could aid in the diagnosis of TPE.

Viral agents associated with poult enteritis and mortality syndrome: the role of a small round virus and a turkey coronavirus

Intestinal samples from turkey poults affected with poult enteritis and mortality syndrome (PEMS) were examined for viruses by immune electron microscopy and double-stranded RNA virus genome electropherotyping. Turkey coronavirus (TCV), avian rotaviruses, reovirus, and a yet undefined small round virus (SRV) were detected. The SRV and TCV were isolated and propagated in turkey embryos. Challenge of specific-pathogen-free turkey poults with SRV, TCV, or both resulted in mortality and clinical responses similar to those of natural PEMS. Our experiments indicate that SRV and TCV are possibly important agents in the etiology of PEMS and the combination of these infections might result in outbreaks with high mortality. The severity of clinical signs and mortality of PEMS are postulated to be partly related to the virus agents involved in individual outbreaks.

A novel synthesis of dibenzo[c,f]chromenes, dibenzo[c,h]chromenes and benzo[7,8]chromeno[3,4-f]isoindoles as antimicrobial agents

Naphtho[2,1-b]pyranone (3) was allowed to react with arylmethylenemalononitriles to yield 4-amino-5-oxo-2-aryl-5H-dibenzo[c,f]chromene-3-carbonitriles (4a,b); with ethyl 3,4-dichlorobenzylidene cyanoacetate to furnish dibenzo[c,f]chromene (5) and with elemental sulfur in dioxane containing piperidine to give thieno[3,4-d]naphtho[2,1-b]pyranone (6). Similarly, naphtho[1,2-b]pyranone (7) was reacted with arylmethylenemalononitriles and elemental sulfur to furnish dibenzo[c,h]chromenes (8) and thieno[3,4-d]naphtho[1,2-b]pyranone (10), respectively. Compound 10 underwent cycloaddition with N-arylmaleimides to yield benzo[7,8]chromeno[3,4-f]isoindoles (11a-c). Some of these compounds were screened in vitro for their antimicrobial activities.

Randomly amplified polymorphic DNA (RAPD) polymerase chain reaction assay for identification of Schistosoma mansoni strains sensitive or tolerant to anti-schistosomal drugs

The genetic differences between Schistosoma mansoni strains from different geographic areas that were reportedly resistant or sensitive to anti-schistosomal drugs were studied with randomly amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) polymerase chain reaction (PCR) assays. Of the 20 RAPD primers we chose, 19 showed the capacity to produce a medium to high level of amplification and 6 revealed difference PCR bands between drug-resistant and drug-sensitive strains. One particular primer, 5'-CAGCGACAAG-3', showed 2 major difference bands between praziquantel (PZQ)-resistant and PZQ-sensitive strains from the endemic area of Egypt. These results demonstrate that defined sequence primers could be applied as a useful tool for differentiating drug-resistant and -sensitive schistosome parasites in the field.

Re-examination of the diagnostic criteria of tropical pulmonary eosinophilia

There is no agreement on the minimum absolute eosinophil count essential for the diagnosis of tropical pulmonary eosinophilia (TPE) at present. The aim of this study was to determine this figure as well as to evaluate the other diagnostic criteria of TPE. The response to diethylcarbamazine (DEC) was tested in 98 patients [of whom 79 (80.6%) completed the study] be means of clinical scores, lung function tests and the absolute eosinophil counts. The minimum absolute eosinophil count necessary for the diagnosis of TPE was found to be 3300 for two reasons. Firstly there was a marked fluctuation in the mean percentage change of the absolute eosinophil count after treatment with DEC, when it was below 3225 cells mm-3, while the mean percentage reduction showed a remarkable stability when the eosinophil count exceeded 3600. Secondly there was a marked difference in the response to DEC in patients whose eosinophil counts were above and below these values. All patients who had eosinophil counts greater than 3600 responded to DEC and were diagnosed as cases of TPE. All of them were from filarial endemic areas. The total eosinophil count decreased by a mean of 92.5%, 3 months after administration of DEC. The sensitivities of the following tests in TPE were as follows: filarial antibody test (FAT) 30%, radiological changes 45.5%, erythrocyte sedimentation rate (ESR) 80%. The radiological changes and the ESR, but not the FAT, were helpful in differentiating TPE from those patients with TPE-like symptoms but with lower eosinophil counts, e.g. those with asthma. Patients with cough who had eosinophil counts of between 53 and 2000 cells mm-3, showed elevated filarial antibody levels in a significant number of cases when compared to asymptomatic subjects. (P < 0.001). Five of them responded to DEC. Three of these had filarial antibody in their serum and one had bilateral mottling on chest X-ray. These results suggest that atypical cases of TPE may exist. Our study has shown that the diagnosis of TPE rests on the following criteria: cough worse at night; residence in a filarial endemic area; the eosinophil count greater than 3300 cells mm-3, clinical and haematological response to DEC. The diagnosis is supported by radiological changes and elevated ESR. The FAT is of little value. The clinical benefit and the improvement in lung function which follows the administration of DEC was sustained up to a minimum period of 15 months.

The role of albendazole in programmes to eliminate lymphatic filariasis

Citing earlier advances in the treatment of lymphatic filariasis [particularly the effectiveness of single-dose diethylcarbamazine (DEC) in reducing microfilaraemia and its enhanced effectiveness when co-administered with single-dose ivermectin], Eric Ottesen, Mahroof Ismail and John Horton consider recent studies on the antifilarial activity of albendazole that have led to the current recommendations for its use in single-dose regimens in conjunction with either DEC or ivermectin for large-scale control/elimination programmes. Furthermore, the potential of albendazole as a macrofilaricide for treating individual patients with lymphatic filarial infections is emphasized as one of a number of important research questions that remain to be explored.

Efficacy of albendazole and its combinations with ivermectin or diethylcarbamazine (DEC) in the treatment of Trichuris trichiura infections in Sri Lanka

The efficacy of the drugs currently available for treatment of infection with Trichuris trichiura is low compared with that of the drugs used against roundworm and hookworm. Single-dose combinations of albendazole with ivermectin or of albendazole with diethylcarbamazine (DEC) have recently been seen to produce raid and sustained reductions in Wuchereria bancrofti microfilaraemia. This observation prompted the present study, on the efficacy of these combinations against trichuriasis. The drug regimens tested were albendazole (400 mg) alone, albendazole (400 mg) with ivermectin (200 micrograms/kg), and albendazole (400 mg) with DEC (6 mg/kg). Most (155) of the 176 children (4-14 years of age) who each provided a single, pre-treatment, stool sample were found positive for Trichuris ova. These 155 were each randomly allocated to one of the three treatment groups and checked for infection 3 weeks post-treatment, again by a single stool examination. Single-dose therapy with albendazole plus ivermectin produced a 'cure rate' (79.3%) and an egg-reduction rate (93.8%) which were significantly higher than the corresponding rates produced by albendazole alone or albendazole plus DEC (P < 0.01 for each). The efficacies of albendazole with DEC and of albendazole alone were statistically equivalent. Single-dose treatment with the albendazole-ivermectin combination appears to be highly effective against trichuriasis and could prove valuable for routine use.

Effect of mebendazole therapy during pregnancy on birth outcome

BACKGROUND

In areas endemic for hookworm, routine antenatal mebendazole therapy could greatly reduce the prevalence of anaemia in pregnancy. At present, however, this is not a widely accepted control strategy because of a lack of data on the safety of the drug. We assessed the effect of mebendazole therapy during pregnancy on birth outcome.

METHODS

A cross-sectional study was done in Sri Lanka, where prescription of mebendazole to women in the second trimester of pregnancy is recommended. Two hospitals were chosen for the study, and women who gave birth there between May, 1996, and March, 1997, were recruited. We compared the rates of major congenital defects, stillbirth, perinatal death, and low birthweight (< or = 1500 g) among babies of mothers who had taken mebendazole during pregnancy with those whose mothers had not taken an anthelmintic (controls).

FINDINGS

The rate of major congenital defects was not significantly higher in the mebendazole group than in the control group (97 [1.8%] of 5275 vs 26 [1.5%] of 1737; odds ratio 1.24 [95% CI 0.8-1.91], p=0.39). Among 407 women who had taken mebendazole in the first trimester (contrary to medical advice), 10 (2.5%) had major congenital defects (odds ratio vs controls 1.66 [0.81-3.56], p=0.23). The proportions of stillbirths and perinatal deaths were significantly lower in the mebendazole group (1.9 vs 3.3%, 0.55 [95% CI 0.4-0.77]), as was the proportion of low-birthweight babies (1.1 vs 2.3%, 0.47 [95% CI 0.32-0.71]).

INTERPRETATION

Mebendazole therapy during pregnancy is not associated with a significant increase in major congenital defects, but our results indicate that it should be avoided during the first trimester. This therapy could offer beneficial effects to pregnant women in developing countries, where intestinal helminthiases are endemic.

Laser thermokeratoplasty after lamellar corneal cutting

PURPOSE

To evaluate the effect of laser thermokeratoplasty (LTK) in eyes that previously had a lamellar corneal cut.

SETTING

University of Al-Azhar, Cairo, Egypt, and Instituto Oftalmológico de Alicante, Spain.

METHODS

In 15 eyes (10 patients), noncontact LTK was applied 6 to 8 weeks after a lamellar corneal cut had been made. Central pachymetry, keratometry, and videokeratography were performed and uncorrected visual acuity, best spectacle-corrected visual acuity (BSCVA), and manifest and cycloplegic refractions measured before and 1, 6, 12, and 18 months after LTK.

RESULTS

Mean follow-up was 19.13 months. Mean refraction was +5.93 diopters (D) +/- 1.9 (SD) before LTK and -0.43 +/- 1.5 D at 1 month, +1.63 +/- 1.6 D at 6 months, 1.91 +/- 1.41 at 12 months, and +2.01 +/- 1.5 D at the end of the study. Total regression did not occur in any case. Mean BSCVA before LTK was 0.66 +/- 0.2, and spontaneous visual acuity at the end of the study was 0.58 +/- 0.18. No patient lost any lines of preoperative BSCVA. There was no significant difference between the results at 12 months and at the end of the study.

CONCLUSION

Corneal lamellar cutting appeared to improve the magnitude of the refractive effect of noncontact LTK and to decrease the amount of regression.

A review of haematogenous osteomyelitis in children in Kuala Lumpur Hospital

We review 81 cases of acute haematogenous osteomyelitis from 1983 to 1990 to establish current pattern of clinical presentation, modes of treatment and success of therapy. Majority of the patient (70%) presented within a week of symptom and significant number of them came with fever and swelling of the affected limb. Sedimentation rate was found to be raised in all of them. Fifty-four (55%) of them were treated surgically. The average antibiotic time was one week by intravenous administration followed by additional oral therapy for period up to four weeks. Average follow-up was 9 months. Six of them (7.5%) end up with various complication which was believed to be due to delay in getting medical treatment.

Noncontact thermokeratoplasty to correct hyperopia induced by laser in situ keratomileusis

PURPOSE

To evaluate the efficacy and safety of noncontact holmium:YAG (Ho:YAG) laser thermokeratoplasty (LTK) for treating hyperopia induced by laser in situ keratomileusis (LASIK).

SETTING

Department of Ophthalmology, University of Alicante, Instituto Oftalmológico de Alicante, Alicante, Spain, and the University of Al-Azhar, Cairo, Egypt.

METHODS

Noncontact LTK was applied to 13 eyes (11 patients) with significant hyperopia after LASIK using a Ho:YAG laser (model gLase 210, Sunrise Technologies). Mean spherical equivalent before LTK was +4.60 diopters (D) +/- 1.40 (SD) (range +2.50 to +7.25 D). The results were evaluated 18 months after the LTK surgery.

RESULTS

A significant myopic shift developed in all eyes that gradually receded to emmetropia 6 to 8 weeks after LTK. After 12 months, refraction was relatively stable. At 18 months, there was a statistically significant difference between the mean uncorrected visual acuity (UCVA) before LTK (0.19 +/- 0.09) and mean postoperative UCVA (0.61 +/- 0.22) (P < .005). At the end of the study, there was a mean increase of 4.10 +/- 1.12 D in central keratometric power. Total regression did not occur in any eye.

CONCLUSION

Noncontact Ho:YAG LTK was safe and effective in correcting LASIK-induced hyperopia. The cutting of Bowman's layer and a thinner corneal center may contribute to the stability of LTK in such cases.

Efficacy of single dose combinations of albendazole, ivermectin and diethylcarbamazine for the treatment of bancroftian filariasis

In a 'blind' trial on 50 male asymptomatic microfilaraemic subjects with Wuchereria bancrofti infection, the safety, tolerability and filaricidal efficacy of a single dose of albendazole (alb) 600 mg alone or in combination with ivermectin (iver) 400 micrograms/kg or diethylcarbamazine citrate (DEC) 6 mg/kg was compared with a single dose of the combination DEC 6 mg/kg and iver 400 micrograms/kg over a period of 15 months after treatment. All but one subject, with 67 microfilariae (mf)/mL, had pre-treatment counts > 100 mf/mL. All 4 treatments significantly reduced mf counts, but alb/iver was the most effective regimen for clearing mf from night blood: 9 of 13 subjects (69%) were amicrofilaraemic by membrane filtration 15 months after treatment compared to one of 12 (8%), 3 of 11 (27%), and 3 of 10 (30%) in the groups treated with alb, alb/DEC, and DEC/iver, respectively. Filarial antigen tests suggested that all 4 treatments had significant activity against adult W. bancrofti; alb/DEC had the greatest activity according to this test, with antigen levels decreasing by 77% 15 months after therapy. All 4 regimens were well tolerated and clinically safe, although mild, self-limited systemic reactions were observed in all treatment groups. These results suggest that alb/iver is a safe and effective single dose regimen for suppression of microfilaraemia in bancroftian filariasis that could be considered for control programmes. Additional benefits of this combination are its potent, broad spectrum activity against intestinal helminths and potential relative safety in areas of Africa where DEC cannot be used for filariasis control because of co-endemicity with onchocerciasis or loiasis.

Human dirofilariasis caused by Dirofilaria (Nochtiella) repens in Sri Lanka

Human dirofilariasis due to Dirofilaria (Nochtiella) repens is a common zoonotic infection in Sri Lanka. Todate 70 cases are on record, and they include 3 expatriates from Russia, England and Korea, who were undoubtedly infected in Sri Lanka. Around 30-60% of dogs are infected with D. repens in various parts of the country and the mosquito vectors are Aedes aegypti, Armigeres subalbatus, Mansonia uniformis and M. annulifera. Unlike in other countries of the old world infection is most common in children under the age of 9 years, the youngest being 4 months old and the scrotum, penis and perianal regions of male children appear to be frequent sites for the worms. Dirofilaria (Dirofilaria) immitis is not present in Sri Lanka though it is present in neighbouring countries like India, and Malaysia.

Laser in situ keratomileusis to correct high myopia

PURPOSE

To evaluate the effectiveness, predictability, and safety of laser in situ keratomileusis (LASIK) in 143 eyes with myopia from 8.00 to 20.00 diopters (D).

SETTING

Alicante Institute of Ophthalmology, University of Alicante School of Medicine, Alicante, Spain.

METHODS

This prospective study comprised 143 eyes (94 patients) that had LASIK with the Chiron Automated Corneal Shaper and the VISX 20/20 excimer laser using a multizone profile and a sutureless hinged corneal flap technique.

RESULTS

Uncorrected visual acuity of 20/40 or better in 45.0% of eyes 3 months postoperatively and in 46.4% at 6 months. Best corrected visual acuity (BCVA) improved by 0.07 at 3 and 6 months and was stable after 3 months. Mean spherical equivalent was -13.19 diopters (D) +/- 2.89 (SD) preoperatively and +0.51 +/- 1.63 D at 3 months and +0.18 +/- 1.66 D at 6 months postoperatively. At 3 months, spherical equivalent was within 1.00 D of emmetropia in 57.5% of all eyes, 71.0% of eyes with a baseline refraction from -8.00 to -11.99 D (n = 59), 44.4% with a baseline refraction from -12.00 to -15.99 D (n = 54), and 53.0% of eyes with a baseline refraction from -16.00 to -20.00 D (n = 30). The respective 6 month percentages were 60.0, 72.4, 46.0, and 50.0%. The regression of effect was similar in all groups (approximately 0.50 D) between 1 and 3 months, although the high myopia group had further regression. Significant corneal steepening and an increase in corneal thickness occurred between 1 and 3 months. Flap thickness was always less than predicted with both the 130 microns plates, and achieved laser ablation was deeper than programmed. The relationships between postoperative refraction and preoperative keratometry and postoperative refraction and the difference in achieved versus programmed ablation were significant. Complications at 6 months included epithelial ingrowth, corneal flap melting, decentered ablation, and irregular astigmatism with loss of BCVA, although none was vision threatening.

CONCLUSION

In this study, LASIK was effective and predictable in the correction of high myopia but was more accurate for myopia up to 12.00 D. Current surgical algorithms must be modified to improve predictability in higher corrections. Longer follow-up is necessary to evaluate long-term incidence of vision-threatening complications.

Correction of Hyperopia with Non-contact Ho:YAG Laser Thermal Keratoplasty

PURPOSE

To assess the potential of non-contact holmium:YAG laser thermal keratoplasty to safely and effectively correct hyperopia up to +5.00 diopters (D).

METHODS

Non-contact laser thermal keratoplasty with a holmium:YAG laser using energies ranging from 215 to 255 mJ with 6, 7, and 8-min ablation zone diameters, was applied to 57 sighted eyes of 42 hyperopic patients in a controlled study. All patients were followed for 15 months after surgery.

RESULTS

Preoperative spectacle-corrected visual acuity returned to baseline levels from 2 to 6 weeks after treatment. Regression of effect was evident in all eyes, and after 15 months was total in 18 eyes (31.5%). The mean cycloplegic refraction before surgery was +3.80 +/- 0.22 D (range, +1.50 to +5.00 D); after surgery, it was +1.40 +/- 0.12 at 3 months, +1.69 +/- 0.19 D at 6 to 8 months, and +1.73 +/- 0.16 D at 15 months. At the end of the study, 41 eyes (71.9%) had an uncorrected visual acuity of 20/40 or better. Thirty-two eyes (58.8%) were within +/- 1.00 D of the intended refraction. Patient age and central pachymetric values were significantly correlated with regression (ANOVA, (p less than .005).

CONCLUSIONS

Regression of initial effect can be large with non-contact holmium:YAG laser thermal keratoplasty. We think the technique works best up to +3.00 D in older individuals with central corneal thickness less than 525 microns. Algorithms to improve the final results should include an initial calculated overcorrection adjusted on variables that influence regression such as patient age and corneal thickness.

Correction of Hyperopia Induced by Photorefractive Keratectomy Using Non-contact Ho:YAG Laser Thermal Keratoplasty

PURPOSE

To evaluate the safety and effectiveness of non-contact holmium:YAG laser thermal keratoplasty in correcting hyperopia induced by photorefractive keratectomy (PRK).

METHODS

Non-contact holmium:YAG laser thermal keratoplasty was applied to 14 eyes with significant hyperopia induced by PRK. The mean spherical equivalent refraction before holmium:YAG laser thermal keratoplasty was +4.20 +/- 1.80 diopters (D) (range, +1.75 to +6.25 D). The results were evaluated 12 months after holmium:YAG laser thermal keratoplasty.

RESULTS

No sight-threatening complications occurred. Recovery of spectacle-corrected visual acuity took from 2 to 6 weeks. The immediate significant myopic shift that developed in all eyes gradually receded over 6 to 8 weeks. All eyes were relatively stable after 9 months. At 12 months, there was no statistically significant difference (p < .005) between the mean preoperative spectacle-corrected visual acuity (0.71 +/- 0.12) and the mean postoperative uncorrected visual acuity (0.65 +/- 0.28). At 12 months there was a mean increase of 4.60 +/- 1.20 D in central keratometric power. Total regression did not occur in any eye.

CONCLUSIONS

Non-contact holmium:YAG laser thermal keratoplasty offers a safe and effective alternative to correct PRK-induced hyperopia.

Prolonged clearance of microfilaraemia in patients with bancroftian filariasis after multiple high doses of ivermectin or diethylcarbamazine

In a double-blind trial on 37 asymptomatic microfilaraemic subjects (minimum 400 microfilariae [mf] per mL) with Wuchereria bancrofti infection, the safety, tolerability and macrofilaricidal efficacy of 12 fortnightly doses of ivermectin, 400 micrograms/kg (ivermectin group), was compared with 12 fortnightly doses of diethylcarbamazine (DEC), 10 mg/kg (DEC group), over a period of 129 weeks after treatment. A control group (LDIC group) was treated with low dose ivermectin to clear microfilaraemia, for ethical reasons. Both ivermectin and DEC in high multiple doses were well tolerated and clinically safe. Macrofilaricidal efficacy was assessed by prolonged clearance of microfilaraemia, appearance of local lesions, and reduction of circulating W. bancrofti adult antigen detected by an antigen capture enzyme-linked immunoassay based on the monoclonal antibody AD12. Mf counts fell more rapidly after ivermectin than after DEC, but low residual mf levels were equivalent in these groups after week 4. Conversely, filarial antigen levels fell more rapidly after DEC than after ivermectin, but low residual antigen levels in these groups were statistically equivalent at all times beyond 12 weeks. Mild, self-limited systemic reactions to therapy were observed in all 3 treatment groups. Local reactions, such as development of scrotal nodules, were observed in several subjects in the DEC and ivermectin groups. These results suggested that high dose ivermectin and DEC both had significant macrofilaricidal activity against W. bancrofti, but neither of these intensive therapeutic regimens consistently produced complete cures. Thus, new drugs or dosing schedules are needed to achieve the goal of killing all filarial parasites in the majority of patients.

Schistosome resistance to praziquantel: Fact or artifact?

Praziquantel is the current drug of choice for human schistosomiasis. Recent reports from laboratory and field studies concerning reduced praziquantel efficacy against Schistosoma mansoni have generated some controversy. The prevailing question is whether the emergence of strains of schistosome resistant to praziquantel is a fact, or an artifact resulting from erroneous field or laboratory experimentation. In this article, Padraic Fallon, Liang-feng Tao, Magdi Ismail and James Bennett examine the available evidence for schistosome resistance to praziquantel. Contributory factors to the schistosomicidal activity of praziquantel, which may interfere with evaluation of drug efficacy or resistance, are also considered.

Prevention of secondary cataract by antimitotic drugs: experimental study

To prevent the development of secondary cataract, mitomycin C (MC, 0.2 mg/ml) and 5-fluorouracil (5-FU, 50 mg/ml) were introduced in the irrigating solution (BSS Plus) during an extracapsular lens extraction in albino rabbits. Cellular multiplication in the whole lens capsule was quantified by means of flow cytometry. The total number of residual cells in the capsule after lens extraction together with the mitotic phases of the cell cycle were studied. A statistically significant difference (p < 0.005, Student t test) was obtained between the two groups treated with antimitotics when compared with the control group regarding the inhibition of mitosis in the capsular cell population together with the total cell number. However, 5-FU has shown a more potent inhibitory effect than MC (p < .0.005, Student t test). We did not record any ocular complication during a postoperative period of 2 months. MC and 5-FU could be a promising alternative in the prevention of posterior capsule opacification.

Laboratory induced resistance to praziquantel in experimental schistosomiasis

To study the effect of praziquantel (PZQ) on successive generations of S. mansoni worms, infected mice were treated 6 weeks after infection with different doses of PZQ (300, 500 mg/kg.), the schistosome strain was originally obtained from an infected Egyptian patient. The eggs subsequently produced by worms that had survived the PZQ treatment were used to infect snails and mice of the following generations. The results were expressed as average number of worms and cure rates in comparison with control groups. It was found that the use of PZQ., especially in low subcurative dose may lead to the development of resistance to therapeutic dose of the drug in following generations.

Treatment of schistosomiasis with praziquantel among school children

This study, as a part of the drug resistance project, one of the activities of the schistosomiasis research project, was carried out in 3 villages in lower Egypt. Its main objective is to assess the praziquantel cure rate and to identify infected persons not responding to praziquantel treatment. Among the studied population, the prevalence of S. mansoni among school children (age 6 to 18 years) was 21.8%, 32.7% and 32.4% in the 3 villages respectively. Those who were found infected were treated with praziquantel (40 mg/kg body weight). The cure rate after six weeks was 75.8%, 83.9% and 72.7% among school children respectively. This cure rate among school children was less than that of adults by 5-10%. Compared with that of preschool age, it showed variable results. A second dose after 6-8 weeks was given to those who were still infected. Those who remained infected even after this second treatment, received a third dose of 60 mg/kg body weight. After the third treatment, only 5 patients of school age remained infected compared to one among adults and one among preschool age. The failure rate was found to be 50%, 18.5% and 12.5% among preschool, school children and adults respectively after the third treatment regimen.

Management of astigmatic keratotomy overcorrections by corneal sutures

Astigmatic overcorrection is a significant possible complication of refractive surgical procedures such as radial keratotomy, astigmatic keratotomy, and combined radial and astigmatic keratotomy. We present the results of a study in which astigmatic overcorrection was reversed by suturing the astigmatic incisions. Videokeratoscopic studies of 15 patients showed that this technique induced a wide range of central corneal steepness, thus correcting variable amounts of astigmatic overcorrection. Mean preoperative uncorrected visual acuity was 20/100 while the mean postoperative uncorrected visual acuity was 20/40. One year after surgery, 13 patients had gained two or more Snellen lines of uncorrected vision; the remaining two had no improvement. Refraction was stable in all cases. No significant complications were observed at one year postoperatively. Corneal sutures may be used safely to manage overcorrections after astigmatic keratotomy or combined radial and astigmatic keratotomy with satisfactory results, even though the predictive value of the technique is limited.

On an infection of a human eye with Parastrongylus (= Angiostrongylus) sp. in Sri Lanka

A metastrongyle worm extracted from the anterior chamber of the right eye of a patient in Sri Lanka belongs to the genus Parastrongylus and probably to a yet undescribed species, related to P. cantonensis well known to infect man. It is mostly a parasite of rodents, wandering in man and unadapted to this host. Evidence for this lack of adaptation are that the specimen is undergoing necrosis (teratological specimen) and is located in an organ with little immunological defences.