Environmental sanitary interventions for preventing active trachoma

BACKGROUND

Trachoma is a major cause of avoidable blindness. It is responsible for about six million blind people worldwide, mostly in the poor communities of developing countries. One of the major strategies advocated for the control of the disease is the application of various environmental sanitary measures to such communities.

OBJECTIVES

To assess the evidence for the effectiveness of environmental sanitary measures on the prevalence of active trachoma in endemic areas.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials - CENTRAL in The Cochrane Library (Issue 2, 2007), MEDLINE (1966 to July 2007), EMBASE (1980 to July 2007), LILACS (July 2007), reference list of trials and the Science Citation Index. We also contacted agencies, experts and researchers in trachoma control.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials comparing any form of environmental hygiene measures with no measure. These hygiene measures included fly control, provision of water and health education. Participants in the trials were people normally resident in the trachoma endemic areas.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed the quality of trials. Study authors were contacted for additional information. Four trials met the inclusion criteria but meta-analysis was not conducted due to heterogeneity of the studies.

MAIN RESULTS

Two studies that assessed insecticide spray as a fly control measure found that trachoma is reduced by at least 55% to 61% with this measure compared to no intervention. However, another study did not find insecticide spray to be effective in reducing trachoma. One study found that another fly control measure, latrine provision, reduced trachoma by 29.5% compared to no intervention; this was, however, not statistically significantly different. Another study revealed that health education on personal and household hygiene reduced the incidence of trachoma such that the odds of reducing trachoma in the health education village was about twice that of the no intervention village. However, all the studies have some methodological concerns relating to concealment of allocation and non-consideration of clustering effect in data analysis.

AUTHORS' CONCLUSIONS

The role of insecticide spray as a fly control measure in reducing trachoma remains unclear. Latrine provision as a fly control measure has not demonstrated significant trachoma reduction. Health education may be effective in reducing trachoma. There is a dearth of data to determine the effectiveness of all aspects of environmental sanitation in the control of trachoma.

Albendazole for lymphatic filariasis

BACKGROUND

Mass treatment with albendazole co-administered with another antifilarial drug is part of a global programme to eliminate lymphatic filariasis. We sought reliable evidence of the effects of albendazole on the disease and the parasite.

OBJECTIVES

To summarize the effects of albendazole alone or in combination with antifilarial drugs for clinical treatment and community control of lymphatic filariasis.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group Specialized Register (August 2005), CENTRAL (The Cochrane Library Issue 3, 2005), MEDLINE (1966 to August 2005), EMBASE (1974 to August 2005), LILACS (1982 to August 2005), and reference lists. We also contacted researchers, the World Health Organization, and GlaxoSmithKline.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials of albendazole alone or combined with another antifilarial drug for treating individuals with lymphatic filariasis, or for reducing transmission in endemic communities.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed eligibility and trial quality, and extracted data. Authors contacted investigators for missing information or clarification.

MAIN RESULTS

Seven trials including 6997 participants (995 with detectable microfilariae) met the criteria. A comparison of albendazole and placebo detected no effect on microfilariae prevalence (920 participants; 3 trials); one trial (499 participants) reported significantly lower microfilariae density at six months. Albendazole performed slightly worse than ivermectin in two trials (436 participants). Compared with diethylcarbamazine (DEC), two small trials (56 participants) found little difference in microfilariae prevalence over an extended follow up. One larger trial (502 participants) found a statistically significant effect for DEC at six months, but none at three months. Microfilariae prevalence and density were statistically significantly lower with the combination of albendazole and ivermectin compared with ivermectin alone in two of three trials (649 participants). Two trials compared albendazole plus DEC with DEC alone and found no statistically significant difference in microfilariae prevalence, though one trial favoured the combination at six months (relative risk 0.62, 95% confidence interval 0.32 to 1.21; 491 participants). This trial also found a statistically significant reduction in microfilariae density.

AUTHORS' CONCLUSIONS

There is insufficient evidence to confirm or refute that albendazole co-administered with DEC or ivermectin is more effective than DEC or ivermectin alone in clearing microfilariae or killing adult worms. Albendazole combined with ivermectin appears to have a small effect on microfilaraemia, but this was not consistently demonstrated. The effect of albendazole against adult and larval filarial parasites, alone and in combination with other antifilarial drugs, deserves further rigorous research.

Environmental sanitary interventions for preventing active trachoma

BACKGROUND

Trachoma is the second or third major cause of blindness. It is responsible for about six million blind people worldwide, mostly in the poor communities of developing countries. One of the major strategies advocated for the control of the disease is the application of various environmental sanitary measures to such communities.

OBJECTIVES

To assess the evidence for the effectiveness of environmental sanitary measures on the prevalence of active trachoma in endemic areas.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials - CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) on The Cochrane Library (Issue 4, 2004), MEDLINE (1966 to January 2005), EMBASE (1980 to January 2005), LILACS (April 2004), the reference list of trials and the Science Citation Index. We also contacted agencies, experts and researchers in trachoma control.

SELECTION CRITERIA

This review included randomised and quasi-randomised controlled trials comparing any form of environmental hygiene measures with no measure. These hygienic measures included fly control, provision of water and health education. Participants in the trials were people normally resident in the trachoma endemic areas.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed the quality of trials. Study authors were contacted for additional information. Three trials met the inclusion criteria but meta-analysis was not conducted due to heterogeneity of the studies.

MAIN RESULTS

Two studies that assessed insecticide spray as a fly control measure found that trachoma is reduced by at least 55% to 61% with this measure compared to no intervention. One study found that another fly control measure, latrine provision, reduced trachoma by 29.5% compared to no intervention; this was, however, not statistically significantly different. Another study revealed that health education on personal and household hygiene reduced the incidence of trachoma such that the odds of reducing trachoma in the health education village was about twice that of the no intervention village. However, all the studies have some methodological concerns relating to concealment of allocation and non-consideration of clustering effect in data analysis.

AUTHORS' CONCLUSIONS

There is evidence that insecticide spray as a fly control measure reduces trachoma significantly. Latrine provision as a fly control measure has not demonstrated significant trachoma reduction. Health education may be effective in reducing trachoma. There is a dearth of data to determine the effectiveness of all aspects of environmental sanitation in the control of trachoma.

Face washing promotion for preventing active trachoma

BACKGROUND

Trachoma remains a major cause of avoidable blindness among underprivileged populations in many developing countries. It is estimated that about 146 million people have active trachoma and nearly six million people are blind due to complications associated with repeat infections.

OBJECTIVES

The objective of this review is to assess the effects of face washing on the prevalence of active trachoma in endemic communities.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials - CENTRAL (which contains the Cochrane Eyes and Vision Group trials register) on The Cochrane Library (Issue 2, 2004), MEDLINE (1966 to February 2004), EMBASE (1980 to February 2004), the reference lists of identified trials and the Science Citation Index. We also contacted investigators and experts in the field to identify additional trials.

SELECTION CRITERIA

We included randomised or quasi-randomised controlled trials, comparing face washing with no treatment or face washing combined with antibiotics against antibiotics alone. Participants in the trials were people normally resident in endemic trachoma communities.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed trial quality. Study authors were contacted for additional information. Two clinically heterogeneous trials are included, therefore a meta-analysis was considered inappropriate.

MAIN RESULTS

This review includes two trials with data from a total of 2560 participants. Face washing combined with topical tetracycline was compared to topical tetracycline alone in three pairs of villages in one trial. The trial found a statistically significant effect for face washing combined with topical tetracycline in reducing 'severe' active trachoma compared to topical tetracycline alone. No statistically significant difference was observed between the intervention and control villages in reducing ('non-severe') active trachoma. The prevalence of clean faces was higher in the intervention villages than the control villages and this was statistically significant. Another trial compared eye washing to no treatment or to topical tetracycline alone or to a combination of eye washing and tetracycline drops in children with follicular trachoma. The trial found no statistically significant benefit of eye washing alone or in combination with tetracycline eye drops in reducing follicular trachoma amongst children with follicular trachoma.

REVIEWERS' CONCLUSIONS

There is some evidence that face washing combined with topical tetracycline can be effective in reducing severe trachoma and in increasing the prevalence of clean faces. Current evidence does not however support a beneficial effect of face washing alone or in combination with topical tetracycline in reducing active trachoma.

Ivermectin for onchocercal eye disease (river blindness)

BACKGROUND

It is believed that ivermectin (a microfilaricide) could prevent blindness due to onchocerciasis. However, when given to everyone in communities where onchocerciasis is common, the effects of ivermectin on lesions affecting the eye are uncertain and data on whether the drug prevents visual loss is unclear.

OBJECTIVES

The aim of this review is to assess the effectiveness of ivermectin in preventing visual acuity and visual field loss in onchocercal eye disease. The secondary aim is to assess the effects of ivermectin on lesions affecting the eye in onchocerciasis.

SEARCH STRATEGY

We searched the Cochrane Eyes and Vision Group specialised register, the Cochrane Controlled Trials Register - CENTRAL, MEDLINE, EMBASE, the reference lists of identified trials, the Science Citation Index and we contacted investigators, experts and pharmaceutical companies to identify additional trials.

SELECTION CRITERIA

We included randomised controlled trials with at least one year follow up, comparing ivermectin at a dose of 150 micrograms per kilogram of body weight with either placebo or no treatment. Participants were people normally resident in endemic onchocercal communities with or without one or more characteristic signs of ocular onchocerciasis.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed trial quality. Study authors were contacted for additional information. Trials varied in design and setting, so no meta-analysis was done.

MAIN RESULTS

This review includes five trials with data from 3810 participants. All the trials compared ivermectin with placebo and were judged to be of moderate risk of bias in terms of methodological quality. No statistically significant difference was observed in any trial (reporting visual acuity outcome) between ivermectin and placebo groups for visual acuity loss.

REVIEWER'S CONCLUSIONS

Questions about the effectiveness of ivermectin in preventing visual acuity loss have not been answered by best available evidence.