Chlamydial infection during trachoma monitoring: are the most difficult-to-reach children more likely to be infected?

OBJECTIVES: During mass antibiotic distributions for trachoma, certain individuals are difficult to locate and go untreated. These untreated individuals may serve as a source of community reinfection. The importance of this difficult-to-locate, untreated population is unclear. We sought to determine whether individuals who are difficult to locate were more likely to be infected with ocular chlamydia than those who were easier to locate. METHODS: We monitored 12 Ethiopian communities 1 year after a third annual mass azithromycin treatment for trachoma. Conjunctival swabbing for chlamydial RNA was performed in a random sample of children from each community. If insufficient numbers of children were enrolled on the first monitoring day, we returned on subsequent days. RESULTS: Of the 12 communities, 10 required more than one monitoring day. On average, 16.1% (95% CI 7.9-30.0) of children were enrolled after the initial day. Evidence of chlamydia was found in 7.1% (95% CI 2.7-17.4) of 0- to 9-year-old children. No ocular swabs collected after the initial day were positive for chlamydial RNA. Children examined after the initial monitoring day were significantly less likely to have ocular chlamydial infection than children seen on the initial day; Mantel-Haenszel common OR = 0 (95% CI 0-0.77). CONCLUSIONS: In a setting of repeated annual mass azithromycin treatments, after approximately 80% of individuals have been located in a community, extra efforts to find absent individuals may not yield significantly more cases of ocular chlamydia.

Rapid Increase in Ownership and Use of Long-Lasting Insecticidal Nets and Decrease in Prevalence of Malaria in Three Regional States of Ethiopia (2006-2007)

Following recent large scale-up of malaria control interventions in Ethiopia; this study aimed to compare ownership and use of long-lasting insecticidal nets (LLIN); and the change in malaria prevalence using two population-based household surveys in three regions of the country. Each survey used multistage cluster random sampling with 25 households per cluster. Household net ownership tripled from 19.6in 2006 to 68.4in 2007; with mean LLIN per household increasing from 0.3 to 1.2. Net use overall more than doubled from 15.3to 34.5; but in households owning LLIN; use declined from 71.7to 48.3. Parasitemia declined from 4.1to 0.4. Large scale-up of net ownership over a short period of time was possible. However; a large increase in net ownership was not necessarily mirrored directly by increased net use. Better targeting of nets to malaria-risk areas and sustained behavioural change communication are needed to increase and maintain net use

Mapping trachoma in Nasarawa and Plateau States, central Nigeria.

OBJECTIVES: The World Health Organization has called upon member states to eliminate blinding trachoma by 2020 using the SAFE strategy. We aimed to determine the prevalence of trachoma and quantify intervention needs for each aspect of the SAFE (surgery, mass administration of antibiotics, promotion of facial cleanliness and environmental improvements) strategy in Nasarawa and Plateau States, Nigeria. METHODS: District-based, household cluster surveys were conducted in all 30 local government areas (LGAs) within the states. RESULTS: A total of 46 960 persons were examined from 7883 selected households. Prevalence estimates of trachomatous inflammation follicular among children 1-9 years of age ranged from 1.7 to 15.8% by LGA. Trichiasis prevalence among adults varied by LGA from 0 to 2.1% and was more common among women (OR = 1.99, 95% CI 1.3 to 3.1). Access to water within a 30 min round trip was reported by 82.3% of households. CONCLUSION: LGA-wide trachoma control interventions are warranted in seven LGAs targeting: 5409 persons for surgery to correct trichiasis, 778 698 persons to receive at least three rounds of mass antibiotic distribution, 855 villages in which to promote face-washing and sanitation, and 102 751 households for latrine construction. These mapping surveys demonstrate an example of evidence-based programme planning necessary for measuring progress towards achieving the GET 2020 objective and can be replicated in other areas yet to be mapped for trachoma.

Evaluation of the prevalence of trachoma 12 years after baseline surveys in Kidal Region, Mali.

OBJECTIVE: After prevalence surveys in all eight regions, Mali started a national programme to control trachoma in 1998. In the sparsely populated desert region of Kidal, where active trachoma prevalence was 46.2% in children under 10, no interventions beyond routine eye-care services were implemented. We estimated the prevalence of trachoma in Kidal, 12 years after baseline mapping surveys, to determine whether interventions to control trachoma were warranted. METHODS: A total of 2165 individuals from 477 households were examined for clinical trachoma signs in a cluster survey using the WHO simplified grading system. Individual and household risk factors for trachoma were assessed. RESULTS: The prevalence of follicular trachomatous inflammation (TF) in children 1-9 years of age was 15.6% (95% CI 11.8-19.5%). Trachomatous trichiasis (TT) was observed in 4 persons for an overall prevalence in all ages of 0.16% (95% CI 0.0-0.35%). Estimated household latrine coverage in the region was 33.1% (95% CI 14.0-52.2%). Residents of 52.8% of surveyed households reported access to a water source outside geographical boundaries of their communities. CONCLUSIONS: In the absence of control interventions, the prevalence of clinical signs of trachoma among children was substantially lower than estimates 12 years earlier. The current prevalence of active trachoma remains above the threshold adopted by WHO, yet there is little evidence of chronic blinding trachoma.

Flies and Helicobacter pylori infection.

Houseflies have been proposed to be a reservoir and vector for Helicobacter pylori. We assessed the effect of insecticide spraying in villages in The Gambia on H. pylori infection in young children. Effective control of flies did not prevent infection with H. pylori.

Changes in house design reduce exposure to malaria mosquitoes.

House design may affect an individual's exposure to malaria parasites, and hence to disease. We conducted a randomized-controlled study using experimental huts in rural Gambia, to determine whether installing a ceiling or closing the eaves could protect people from malaria mosquitoes. Five treatments were tested against a control hut: plywood ceiling; synthetic-netting ceiling; insecticide-treated synthetic-netting ceiling (deltamethrin 12.5 mg/m2); plastic insect-screen ceiling; or the eaves closed with mud. The acceptability of such interventions was investigated by discussions with local communities. House entry by Anopheles gambiae, the principal African malaria vector, was reduced by the presence of a ceiling: plywood (59% reduction), synthetic-netting (79%), insecticide-treated synthetic-netting (78%), plastic insect-screen (80%, P < 0.001 in all cases) and closed eaves (37%, ns). Similar reductions were also seen with Mansonia spp., vectors of lymphatic filariasis and numerous arboviruses. Netting and insect-screen ceilings probably work as decoy traps attracting mosquitoes into the roof space, but not the room. Ceilings are likely to be well accepted and may be of greatest benefit in areas of low to moderate transmission and when used in combination with other malaria control strategies.

Human and other faeces as breeding media of the trachoma vector Musca sorbens.

The fly Musca sorbens Wiedemann (Diptera: Muscidae) apparently transmits Chlamydia trachomatis, causing human trachoma. The literature indicates that M. sorbens breeds predominantly in isolated human faeces on the soil surface, but not in covered pit latrines. We sought to identify breeding media of M. sorbens in a rural Gambian village endemic for trachoma. Test breeding media were presented for oviposition on soil-filled buckets and monitored for adult emergence. Musca sorbens emerged from human (6/9 trials), calf (3/9), cow (3/9), dog (2/9) and goat (1/9) faeces, but not from horse faeces, composting kitchen scraps or a soil control (0/9 of each). After adjusting for mass of medium, the greatest number of flies emerged from human faeces (1426 flies/kg). Median time for emergence was 9 (inter quartile range = 8-9.75) days post-oviposition. Of all flies emerging from faeces 81% were M. sorbens. Male and female flies emerging from human faeces were significantly larger than those from other media, suggesting that they would be more fecund and live longer than smaller flies from other sources. Female flies caught from children's eyes were of a similar size to those from human faeces, but significantly larger than those from other media. We consider that human faeces are the best larval medium for M. sorbens, although some breeding also occurs in animal faeces. Removal of human faeces from the environment, through the provision of basic sanitation, is likely to greatly reduce fly density, eye contact and hence trachoma transmission, but if faeces of other animals are present M. sorbens will persist.

Review of the evidence base for the 'F' and 'E' components of the SAFE strategy for trachoma control.

Community control of trachoma as a blinding disease is based on the SAFE strategy of Surgery, Antibiotic therapy, Facial cleanliness and Environmental improvement. Surgery and antibiotic therapy currently dominate most programmes. Blindness from trachoma results from frequent infections repeated over many years, so ultimate success requires the reduction of transmission. This is only likely to be sustainable through the F and E components of SAFE. Environmental improvement with access to water, enhanced hygiene and better sanitation reduces trachoma transmission and the blinding sequelae eventually disappear. Transmission routes and factors that cause this are not known and consequently no single specific tool for F and E is in place. Evidence from intervention studies shows that the promotion of face-washing gave modest gains for intense effort and a pilot study showed that trachoma transmission was reduced in the absence of eye-seeking flies. Other studies have shown that latrines and improved access to water are associated with a lower prevalence of active trachoma. There is likely to be a long-term beneficial effect of a combination of improved water supplies, provision of latrines, facial hygiene promotion through established infrastructure and control of eye-seeking flies. Each of these interventions offers additional public health and other benefits in its own right. Further research on the routes of transmission, the role of hygiene and means of sustainable fly control should be a priority.

Transmission ecology of the fly Musca sorbens, a putative vector of trachoma.

Recent evidence suggests that eye-seeking flies are important trachoma vectors. We conducted a series of investigations to identify which species of synanthropic flies are potential vector(s) of this blinding disease in The Gambia. Several species of fly were caught in fish-baited attractant traps placed in villages throughout the year (1997/98) but only 2 species, Musca sorbens and M. domestica, were caught from the eyes of children. M. sorbens comprised < 10% of the total number of flies caught with attractant traps but was responsible for > 90% of fly-eye contacts, the remainder were made by M. domestica. All fly species were more numerous in the wet season than the dry season. Eyes of young children are considered to be the main reservoir of Chlamydia trachomatis, the causative agent of trachoma. Collections of eye-seeking flies from children showed frequent fly-eye contacts (median [interquartile range], 3 [1.5-7] every 15 min). Children with potentially infective ocular or nasal discharge had twice as many fly-eye contacts than children with no discharge (P < 0.001). There was no difference in exposure to fly-eye contacts if a child sat inside or outside a house (P = 0.273). Female flies were more commonly caught from eyes than male (P < 0.001). The presence of Chlamydia DNA was demonstrated by PCR on 2 of 395 flies caught from the eyes of children with a current active trachoma infection. Both positive flies were M. sorbens, one male and the other female. Further elucidation of M. sorbens behavioural ecology and the development of sustainable strategies to control these flies should be a priority. It is likely that M. sorbens is the principal insect vector of trachoma in The Gambia.

Effect of fly control on trachoma and diarrhoea.

BACKGROUND: Domestic flies are accepted vectors of diarrhoea, but their role in trachoma transmission has never been quantified and no study has shown that fly control decreases the prevalence of trachoma. We assessed the effect of fly control on public health in a pilot study in Gambian villages. METHODS: We studied two pairs of villages--one pair in the 1997 wet season, and one pair in the 1998 dry season. For each pair, deltamethrin was sprayed for 3 months to control flies in one village whilst the other was used as a control. Fly populations were monitored with traps. We surveyed trachoma at baseline and at 3 months, and collected daily data on diarrhoea in children aged between 3 months and 5 years. FINDINGS: Fly control decreased numbers of muscid flies by around 75% in the intervention villages compared with controls. Trachoma prevalence was similar at baseline (wet season, prevalence in intervention village 8.8% vs control 12.2%; dry season, 18.0% vs 16.0%), but after 3 months of fly control there were 75% fewer new cases of trachoma in the intervention villages (wet season 3.7% vs 13.7%; dry season 10.0% vs 18.9%; rate ratio and relative risk of pooled data 0.25 [adjusted 95% CI 0.09-0.64], p=0.003). There was 22% less childhood diarrhoea in the wet season (14% vs 19%, period prevalence ratio 0.78 [0.64-0.95], p=0.01), and 26% less diarrhoea in the dry season (6% vs 8%; 0.74 [0.34-1.59], p=0.60) compared with controls. INTERPRETATION: Muscid flies are important vectors of trachoma and childhood diarrhoea in The Gambia. Deltamethrin spray is effective for fly control and may be useful for reducing trachoma and diarrhoea in some situations, but further research on sustainable fly-control methods is needed.

PIP: The causative agent of trachoma, Chlamydia trachomatis, has been found on flies fed on heavily infected laboratory culture media. Findings are presented from an assessment of the effect of domestic fly control upon the prevalence of trachoma and associated cases of childhood diarrhea in 2 pairs of Gambian villages. 1 pair of villages was studied in the 1997 wet season and the second pair in the 1998 dry season. For each pair, deltamethrin was sprayed for 3 months to control flies in 1 village, while the other village was used as a control. Fly populations were monitored with traps. The prevalence of trachoma was measured at baseline and at 3 months, and data were collected daily on diarrhea in children aged 3 months to 5 years. Fly control decreased the numbers of muscid flies by approximately 75% in the intervention villages compared with controls. While the prevalence of trachoma was similar at baseline between study and control villages, after 3 months of fly control there were 75% fewer new cases of trachoma in the intervention villages. There was 22% and 26% less childhood diarrhea in the wet and dry seasons, respectively, compared with controls. These findings demonstrate that muscid flies are important vectors of trachoma and childhood diarrhea in The Gambia, and that the use of deltamethrin spray can help to reduce the prevalence of both trachoma and associated diarrhea cases.

Oesophageal varices associated with busulphan-thioguanine combination therapy for chronic myeloid leukaemia.

5 patients receiving continuous busulphan and 6-thioguanine for chronic myeloid leukaemia (CML) were found to have oesophageal varices associated with abnormal liver function tests. 3 of these cases presented with gastrointestinal haemorrhage and 1 patient died. The 2 other cases had varices discovered at endoscopy. Nodular regenerative hyperplasia (NRH) of the liver was identified as the cause of portal hypertension in the 4 patients on whom liver biopsies were done. The administration of busulphan and thioguanine in combination is likely to be associated with the development of NRH, with portal hypertension and oesophageal varices occurring in a substantial proportion of cases.

An improved method for the measurement of red cell survival using non-radioactive chromium.

An improved technique for the measurement of red cell survival is described in which non-radioactive 50Cr is used in patients for whom radioactive labels are not advisable. The 50Cr was measured by neutron activation analysis using a high resolution germanium (lithium) diode gamma-ray spectrometer. In adult controls, the values obtained were in the range accepted as normal for the 51Cr method, and double labelling experiments showed close agreement. The application of this technique to the measurement of red cell survival in pregnant women suspected of having haemolytic anemia is described.

Congenital haemolytic anaemia resulting from glucose phosphate isomerase deficiency: genetics, clinical picture, and prenatal diagnosis.

Glucose phosphate isomerase (GPI) deficiency with severe haemolysis and hydrops fetalis was found in the first child of unrelated, healthy Caucasian parents. The child died at 3 hours. Both parents were found to have 50% of normal red cell GPI activity and qualitative tests on their red cells and white cells showed that each was heterozygous for a different GPI variant allele associated with enzyme deficiency. Tests on the placenta showed that the propositus was a 'compound' heterozygote. Examination of amniotic cells obtained by amniocentesis on the mother at 28 weeks in her second pregnancy led to the prenatal diagnosis of GPI deficiency. This second child, a 'compound' heterozygote at the GPI locus indistinguishable from the first, was successfully treated by immediate exchange transfusion and subsequent blood transfusions.

Clinical events relating to intraventricular haemorrhage in the newborn.

Continuous measurements of arterial pressures, heart rates, respiratory movements, and respiratory rates were made from birth in 44 infants at risk from intraventricular haemorrhage (IVH). 17 babies died with IVH, in 10 of whom the event was timed objectively. Events in these babies were compared with survivors of similar birthweights, gestational ages, severity of birth asphyxia, and severity of hyaline membrane disease (HMD). IVH followed severe HMD and was associated with cessation of the babies' own respiratory efforts while on a ventilator and also with characteristic cardiorespiratory events. The minimum arterial pressure before IVH was lower than in comparable babies who survived. It is suggested that fluctuations of systemic blood pressure from initial low levels may be important in the pathogenesis of IVH. It is possible that changes in cerebral blood flow are of even greater significance.