A novel aqueous dimethyl trisulfide formulation is effective at low doses against cyanide toxicity in non-anesthetized mice and rats

BACKGROUND

Cyanide (CN) is a metabolic poison that is capable of intoxicating individuals through accidental or intentional means. With high concentration exposures, death can occur in minutes. In cases of mass casualty exposures, there is a need for a rapid-acting countermeasure capable of being administered in a short period of time in a pre-hospital setting to treat victims.

OBJECTIVE

These studies evaluate the safety and efficacy of a novel aqueous formulation of dimethyl trisulfide (DMTS) as an intramuscular (IM) CN countermeasure using non-anesthetized rodent models.

METHODS

Non-anesthetized rodents (mice and rats) were exposed to hydrogen cyanide (HCN) or potassium cyanide (KCN) along with immediate IM 10% DMTS treatment or vehicle treatment. Survival and other parameters, such as the time to recovery and assessment of clinical toxic signs (e.g., gasping, loss of righting reflex, convulsions, etc.), were quantified to determine the effectiveness of 10% DMTS treatment (12.5, 25, 75 mg/kg IM) compared to vehicle control treatment. A rat KCN delayed-treatment model with a 15-minute treatment delay was also utilized to simulate a real-life exposure/treatment scenario with 10% DMTS treatment. The stability of the 10% DMTS formulation was also assessed.

RESULTS

A 25 mg/kg IM dose of 10% DMTS exhibits potent efficacy against subcutaneous (SC) KCN challenge in both mice and rats and inhalational HCN exposure in mice. 10% DMTS treatment also shortens the time to recovery in rats using a delayed-treatment model.

CONCLUSION

IM treatment with 10% DMTS improves survival and clinical outcomes in non-anesthetized rodent models of acute CN toxicity. Additionally, the use of an SC KCN delayed-treatment model in rats is advised to assess the performance of a candidate CN countermeasure in a more realistic exposure/treatment scenario.

Can nature-based solutions contribute to water security in Bhopal?

Bhojtal, a large man-made lake bordering the city of Bhopal (Madhya Pradesh state, central India), is important for the city's water supply, connoted the lifeline of the city. Despite the dry though not arid and markedly seasonal climate, soil impermeability hampers infiltration into the complex geology underlying the Bhojtal catchment. Rural communities in the catchment are nonetheless high dependent on underlying aquifers. This paper develops baseline understanding of trends in the ecology, water quality and uses of Bhojtal, discussing their implications for the long-term wellbeing of the Bhopal city region. It highlights increasing dependency on water diverted from out-of-catchment sources, and also abstraction across the Bhojtal catchment in excess of replenishment that is depressing groundwater and contributing to reported declining lake level and water quality. Despite some nature-based management initiatives, evidence suggests little progress in haltering on-going groundwater depression and declines in lake water level and quality. Significant declines in ecosystem services produced by Bhojtal are likely without intervention, a major concern given the high dependency of people in the Bhopal region on Bhojtal for their water supply and socio-economic and cultural wellbeing. Over-reliance on appropriation of water from increasingly remote sources is currently compensating for lack of attention to measures protecting or regenerating local resources that may provide greater resilience and regional self-sufficiency. Improved knowledge of catchment hydrogeology on a highly localised scale could improve the targeting and efficiency of water harvesting and other management interventions in the Bhojtal catchment, and their appropriate hybridisation with engineered solutions, protecting the catchment from unintended impacts of water extraction or increasing its carrying capacity, and also providing resilience to rising population and climate change. Ecosystem service assessment provides useful insights into the breadth of benefits of improved management of Bhojtal and its catchment.

Population-based evaluation of the 'LiveLighter' healthy weight and lifestyle mass media campaign

The Western Australian (WA) 'LiveLighter' (LL) mass media campaign ran during June-August and September-October 2012. The principal campaign ad graphically depicts visceral fat of an overweight individual ('why' change message), whereas supporting ads demonstrate simple changes to increase activity and eat healthier ('how' to change message). Cross-sectional surveys among population samples aged 25-49 were undertaken pre-campaign (N= 2012) and following the two media waves (N= 2005 and N= 2009) in the intervention (WA) and comparison state (Victoria) to estimate the population impact of LL. Campaign awareness was 54% after the first media wave and overweight adults were more likely to recall LL and perceive it as personally relevant. Recall was also higher among parents, but equal between socio-economic groups. The 'why' message about health-harms of overweight rated higher than 'how' messages about lifestyle change, on perceived message effectiveness which is predictive of health-related intention and behaviour change. State-by-time interactions showed population-level increases in self-referent thoughts about the health-harms of overweight (P < 0.05) and physical activity intentions (P < 0.05). Endorsement of stereotypes of overweight individuals did not increase after LL aired. LL was associated with some population-level improvements in proximal and intermediate markers of campaign impact. However, sustained campaign activity will be needed to impact behaviour.

Effects of nutrient content claims, sports celebrity endorsements and premium offers on pre-adolescent children's food preferences: experimental research

OBJECTIVES

To assess pre-adolescent children's responses to common child-oriented front-of-pack food promotions.

METHODS

Between-subjects, web-based experiment with four front-of-pack promotion conditions on energy-dense and nutrient-poor (EDNP) foods: no promotion [control]; nutrient content claims; sports celebrity endorsements (male athletes) and premium offers. Participants were 1302 grade 5 and 6 children (mean age 11 years) from Melbourne, Australia. Participants chose their preferred product from a randomly assigned EDNP food pack and comparable healthier food pack then completed detailed product ratings. Child-oriented pack designs with colourful, cartooned graphics, fonts and promotions were used.

RESULTS

Compared to the control condition, children were more likely to choose EDNP products featuring nutrient content claims (both genders) and sports celebrity endorsements (boys only). Perceptions of nutritional content were enhanced by nutrient content claims. Effects of promotions on some product ratings (but not choice) were negated when children referred to the nutrition information panel. Premium offers did not enhance children's product ratings or choice.

CONCLUSIONS

Nutrient content claims and sports celebrity endorsements influence pre-adolescent children's preferences towards EDNP food products displaying them. Policy interventions to reduce the impact of unhealthy food marketing to children should limit the use of these promotions.

Influence of smoking abstinence and nicotine replacement therapy on heart rate and QT time-series

SUMMARY

Many smokers attempt to quit without using nicotine replacement therapy (NRT) or pharmacotherapy, i.e. 'cold-turkey'. The cardiac implications of this are important but are incompletely understood. Previous studies have associated smoking cessation with improvements in heart rate (HR) and its variability, but its influence on QT time-series is unclear. Furthermore, the relative influence on these parameters of acute nicotine withdrawal and of NRT has not been adequately compared. Additional insight might come from analysing the dynamic (e.g. fractal) properties of electrocardiographic data during different levels of nicotine exposure. We examined the influence of smoking cessation, during cold-turkey and subsequent NRT, on HR and QT time-series during 30 days of smoking abstinence. Seven smokers and sixteen healthy non-smokers received ECG monitoring at baseline (Day 0). Smokers subsequently refrained from smoking without using NRT for 24 h, and then received NRT for 29 days. ECG monitoring was repeated at Days 1, 7, 30. Following smoking cessation we observed that: HR and rate-corrected QT were both reduced, heart rate variability (HRV) increased (improved), and QT variability index (QTVI) showed signs of improvement (trend only). Improvements in HR and QT were maintained throughout NRT use, whilst improvements in HRV and QTVI were sustained for at least the early stages of NRT. The dynamic (multifractal) properties of HR and QT were similar for smokers and non-smokers, and were unchanged by smoking abstinence or NRT. Our results provide tentative evidence that electrocardiographic improvements during a cold-turkey smoking quit attempt (acute nicotine withdrawal) are maintained during NRT pharmacotherapy.

The anatomical tibial axis: reliable rotational orientation in knee replacement

The rotational alignment of the tibia is an unresolved issue in knee replacement. A poor functional outcome may be due to malrotation of the tibial component. Our aim was to find a reliable method for positioning the tibial component in knee replacement. CT scans of 19 knees were reconstructed in three dimensions and orientated vertically. An axial plane was identified 20 mm below the tibial spines. The centre of each tibial condyle was calculated from ten points taken round the condylar cortex. The tibial tubercle centre was also generated as the centre of the circle which best fitted eight points on the outside of the tubercle in an axial plane at the level of its most prominent point. The derived points were identified by three observers with errors of 0.6 mm to 1 mm. The medial and lateral tibial centres were constant features (radius 24 mm (SD 3), and 22 mm (SD 3), respectively). An anatomical axis was created perpendicular to the line joining these two points. The tubercle centre was found to be 20 mm (SD 7) lateral to the centre of the medial tibial condyle. Compared with this axis, an axis perpendicular to the posterior condylar axis was internally rotated by 6 degrees (SD 3). An axis based on the tibial tubercle and the tibial spines was also internally rotated by 5 degrees (sd 10). Alignment of the knee when based on this anatomical axis was more reliable than either the posterior surfaces or any axis involving the tubercle which was the least reliable landmark in the region.

Antigen selection for future anti-Trichuris vaccines: a comparison of cytokine and antibody responses to larval and adult antigen in a primary infection

Trichuriasis, caused by the whipworm Trichuris trichiura, is endemic in tropical and subtropical areas, affecting approximately 1 billion people. Child anthelminthic treatment programmes are being implemented but repeated treatments are costly, may prevent the development of acquired immunity and can lead to the development of drug resistant parasites. Thus, the development of a vaccine which would lead to the acquisition of immunity at an earlier age and reduce community faecal egg output would be beneficial. Development of subunit vaccines requires the identification of protective antigens and their formulation in a suitable adjuvant. Trichuris muris is an antigenically similar laboratory model for T. trichiura. Subcutaneous vaccination with adult excretory-secretory products (ES) protects susceptible mouse strains from T. muris. Larval stages may contain novel and more relevant antigens which when incorporated in a vaccine induce worm expulsion earlier in infection than the adult worm products. This study finds negligible difference in the cellular and humoral immune response to T. muris adult and third stage larva(e) (L3) ES during a primary T. muris infection, but identifies high molecular weight proteins in both adult and L3 ES as potential vaccine candidates.

Microcapsule-gel formulation of promethazine HCl for controlled nasal delivery: a motion sickness medication

The current method of choice for astronauts to treat space motion sickness is an intra-muscular injection of promethazine hydrochloride (PMZ HCl) which is invasive and causes considerable local irritation and discomfort at the site of injection. Intra-nasal delivery is considered a feasible alternative route for administration of medications to treat space motion sickness. The purpose of this research is to develop a PMZ HCl formulation that can be administered intra-nasally without irritation (i.e. leukocyte infiltration) in the nasal epithelium when dosed at PMZ HCl concentrations greater than the cytotoxic limit. The biocompatibility of PMZ HCl was tested in vitro and was shown to be cytotoxic at concentrations greater than 10(-5) molar regardless of pH. A controlled-release microencapsulated dosage formulation was developed using spinning disk atomization and release rates for the PMZ HCl microcapsules were determined in phosphate buffered saline. An animal study was conducted to determine the irritation response of rat nasal mucosa when dosed with encapsulated and non-encapsulated PMZ HCl.

Mucosal delivery of cytotoxic therapeutic agents: response of rat nasal mucosa to microencapsulated ethopropazine HCl enantiomer

Use of microencapsulation technology in combination with absorption enhancers eliminated epithelium irritation and necrosis commonly associated with nasal delivery of cytotoxic therapeutic agents. Phenothiazines, such as ethopropazine (ETZ), promethazine, trimeprazine and propiomazine have been used for the treatment of allergenic conditions, motion sickness, nausea, Parkinson's disease, Prion disease and as a sedative for psychiatric disorders. The enantiomers of commercially available racemic phenothiazines were isolated and purified using classical diastereomeric salt techniques. The racemate and the enantiomers of ETZ were tested in vitro for their cellular toxicity using lung fibroblast cells. Each enantiomer was shown to be cytotoxic at concentrations greater than 10(-5) molar. The ETZ enantiomers were encapsulated using spinning disk atomization to prepare a nasal delivery dosage form that does not produce an irritation response. Release rates for the ETZ microcapsules were determined in vitro and an animal study was conducted to determine the irritation response of rat nasal mucosa when dosed with encapsulated vs. non-encapsulated ETZ.

Does receiving a copy of correspondence improve patients' satisfaction with their out-patient consultation?

It is standard practice to write to a patient's general practitioner (GP) following an out-patients consultation. This study set out to assess whether sending a copy of this letter to the patient improves their satisfaction with the consultation. Two hundred patients were randomly assigned to receive or not to receive a copy of their GP letter. Their satisfaction was then assessed by means of a postal questionnaire. The two groups were compared to ensure that their was no significant difference between them with regard to any other aspect of their consultation. Those who did not receive a copy letter had a median overall satisfaction score of 7.75 whilst those who did had a median score of 9.0 (p = 0.014). The only other factors predictive of overall satisfaction were receiving an explanation of the problem and spending sufficient time with the doctor. Sending patients a copy of correspondence to their GP is one means of aiding communication and improving overall satisfaction.

Metal-oxide nanoparticles for the reinforcement of dental restorative resins

Metal oxide nanoparticles were synthesized from tantalum ethoxide and zirconium isopropoxide and subsequently surface grafted with vinyl silane and silyl methacrylate coupling agents. The nanoparticles were then dispersed into a commercial dental resin, and the composite was photocured into rigid three-point bend and fracture toughness specimens. The optically transparent/translucent cured composites demonstrated strength, toughness, and elastic modulus inferior to the unfilled material. Therefore, modifications in surface functionalization are being made to improve coupling and reduce interparticle associations.

The Breast Cancer Distance Education Program: development and evaluation of a course for specialist breast care nurses

The Breast Cancer Distance Education Program is the first tertiary-based education program for specialist breast care nurses in Australia. The program covers current treatment options, psychosocial issues, and professional development issues relating to breast cancer nursing. For the first two student intakes (n = 53), precourse, postcourse, and 3-month follow-up surveys were conducted to assess the perceived value of the course, identify any limitations, and note changes in practice that arose. Before taking the course, most of the students had experience in breast cancer nursing, but lacked confidence and hoped to learn more about responding effectively to psychosocial issues through communication, counseling, and provision of support to patients and their carers. After taking the course, the students were very positive about the course content, resources, and teaching support. They reported learning new skills for addressing psychosocial issues and symptom management arising from a diagnosis of breast cancer, stating a desire to implement these new skills. Comparison between results from the three surveys indicated that students' confidence in providing breast cancer support increased significantly in most areas of practice, and was maintained at 3-month follow-up survey. Results suggest that students met the course objectives successfully, and in most cases subsequently translated their knowledge into improved practice.

Personal Dental Services--a practitioner's point of view

NHS dentistry has seen many changes recently. The latest has been the introduction of Personal Dental Services. This article describes the experiences of two general dental practitioners in their practice who entered as a first wave pilot. The article explains the steps involved in generating a proposal and preparing a practice to run as a pilot. The authors have highlighted areas of particular concern for others to consider before embarking on a similar journey.

Promoting sun protection in children: rationale and challenges

This article outlines the epidemiological and educational arguments for promoting sun protection during childhood and highlights factors that may facilitate or hinder achievement of this behavioral outcome. A model describing behavioral factors in the causation of skin cancer is presented. Summary results from previous behavioral studies and interventions relating to primary prevention of skin cancer are described, and recent data on the cost-effectiveness of sun protection in Australia and its implications for health insurers are discussed. This article also includes a commentary on the demonstration projects promoting skin cancer prevention among children and their caregivers featured in this special issue of Health Education and Behavior.

Comparison of albumin versus bicarbonate treatment for neonatal metabolic acidosis

In this study the effectiveness of 4.5% human albumin was compared with 4.2% sodium bicarbonate for neonatal metabolic acidosis, using a randomised controlled trial. The change in median pH following bicarbonate was more than twice that in the albumin group. This was statistically significant.

CONCLUSION

In normotensive infants, use of bicarbonate to correct metabolic acidosis may be more effective than use of albumin.

Radiopacity of tantalum oxide nanoparticle filled resins

OBJECTIVES

Radiopacity of composite resins allows radiographic distinction of existing restorations and recurrent caries. Current composites must be supplemented with heavy metal-containing glasses or minerals to achieve a desired radiopacity. The purpose of this study was to evaluate the radiopacity of Tantalum oxide (Ta2O5) filled resins at varying percentage loadings.

METHODS

Methacrylate functionalized Ta2O5 nanoparticles (< 50 nm) in methanol-dissolved or powder forms were mixed into either glycerol dimethacrylate (GDMA) or a bisGMA, TEGDMA, bisEMA mixture (GTE). Specimens were made in a split brass mold (2 x 2 x 15 mm) and compared with an aluminum stepwedge (99.5% pure Al) and a dentin slice of the same thickness. Kodak Ultraspeed periapical X-ray film on a lead plate at a target distance of 45 cm was exposed at 70 kVp and 10 mA, for 0.5 s and processed automatically. Optical density was measured (n = 3) with an RMI Processor Control Densitometer. Radiopacity was calculated as percent relative linear attenuation coefficient (Alpha). ANOVA and Student-Newman-Keuls comparisons were used to determine significance at the 95% confidence level.

RESULTS

Radiopacity increased significantly with Ta2O5 loading (p = 0.001). Ta2O5 nanoparticle filled resins enter the optimal range of diagnostic detectability (alpha = 150-250) at 50 wt.% and approach equivalence with enamel at approximately 70 wt.%.

SIGNIFICANCE

The introduction of tantalum oxide nanoparticle filler has potential as a miscible component of a resin composite to provide radiopacity for microfiller-type restorative materials and to circumvent the need for hydrolysis-prone glass reinforcing fillers.

Sun protection and sunburn in primary school children: the influence of age, gender, and coloring

BACKGROUND

Childhood is a high-risk period for skin damage due to excessive sun exposure. This damage may lead to skin cancer later in life.

METHODS

The present study measured children's knowledge and attitudes, and reported usual behavior relevant to sun protection and parents' encouragement of their children's sun protection among a sample of 735 primary school students and their parents, in Victoria, Australia. The incidence of sunburn among the children over late spring and early summer was monitored weekly for 8 weeks.

RESULTS

The results indicate that children's knowledge of sun protection is moderately high and that positive sun protection attitudes, reported frequency of parents encouraging protection, and children carrying out sun protection are generally high. Trends for age indicate that while knowledge of sun protection increases with age, attitudes and behaviors supportive of sun protection decline. Sunburn rates increase with age. There was some evidence to suggest that children with fairer coloring receive greater encouragement from parents to protect themselves and are marginally better protected than children with darker coloring. However, this highly susceptible group still suffers more burns. There was little variation based on children's gender.

CONCLUSIONS

The mid-primary school years may be a critical time for interventions promoting sun protection.

Public reaction to Victoria's "2 Fruit 'n' 5 Veg Every Day" campaign and reported consumption of fruit and vegetables

BACKGROUND

The Victorian "2 Fruit 'n' 5 Veg Every Day" campaign was aimed at increasing awareness of the need to eat more fruit and vegetables and encouraging increased consumption of these foods in the Australian state of Victoria. The demand-side component of the campaign, which had television advertising as a centerpiece, ran from 1992 to 1995.

METHODS

Annual postcampaign telephone surveys of approximately 500 Victorians ages 20 and over were conducted with the aim of examining public awareness of the campaign, beliefs about desirable eating habits for fruit and vegetables, and reported consumption of these foods.

RESULTS

Over the years, patterns in the level of public awareness, reported consumption, and beliefs about appropriate levels of consumption have tended to parallel changes in the level of mass media investment. During the campaign's most intense period of promotional activity, significant increases in all of these variables occurred.

CONCLUSIONS

The results suggest that significant achievements can be made with relatively small-budget mass media promotion of dietary recommendations, especially when part of a more comprehensive program. However, campaigns may need to be adequately resourced for several years if sustained change is to be achieved.

Effects of dietary fatty-acid supplementation on fatty-acid composition and deformability of young and old erythrocytes

The effects of cell age on erythrocyte phospholipid fatty-acid composition and deformability were examined in 20 healthy adults (11 male, 9 female) prior to and following 12 weeks of dietary supplementation with 3.5 g/day of safflower oil (high in n - 6 fatty acids) or fish oil (high in n - 3 fatty acids). In the absence of dietary supplementation, old erythrocytes demonstrated an increase in filtration time (P < 0.001), an increase in membrane phospholipid total n - 6 fatty acids (P < 0.01), and a decrease in total n - 3/total n - 6 ratio (P < 0.01) compared to young erythrocytes. Both safflower and fish oil supplementation attenuated age-related differences in membrane phospholipid total n - 6 and total n - 3 fatty acids. Fish oil supplementation also increased the proportion of n - 3 fatty acids (P < 0.01) and the n - 3/n - 6 ratio (P < 0.05) in the phospholipids of both young and old erythrocytes, and eliminated age-related differences in erythrocyte filtration time by reducing the relative filtration time of the old erythrocytes.

Liver ultrasound findings in a low prevalence area of S. japonicum in China: comparison with history, physical examination, parasitological and serological results

The paper describes a study carried out in a community in Dongdian township, Anhui Province, People's Republic of China. Medical history and the results of a physical examination, ultrasound investigation, parasitological and serological tests for Schistosoma japonicum infection were compared in 661 persons of 169 households. A lack of correlation between parasitological and serological indicators of infection and morbidity was observed in this area of low (6.4%) prevalence and intensity of infection. The prevalence of abnormal ultrasound findings in the liver in this population was high (56%), and was significantly higher than the prevalence of S. japonicum infection. The abnormal ultrasound findings correlated with a history of schistosomiasis, and the correlation increased significantly according to the number of times treated and the time since the last treatment, which suggested that past parenteral treatment has a role in the high rate of abnormal liver ultrasound findings. The significant correlation between the qualitative and quantitative serological results and abnormal ultrasound parenchymal patterns suggests that cross-reactivity between the etiology of the parenchymal disease and these tests is occurring. The presence of HBsAg correlated with the composite presence of ultrasound abnormalities of the liver parenchyma: increased echogenicity, periportal fibrosis and/or nodules and irregular fibrosis, whereas a normal ultrasound pattern was associated with the absence of HBV antigenemia.

Attenuation of cyclosporine-induced hypertension by dietary fatty acids in the borderline hypertensive rat

The effects of dietary (10% calories) safflower (SAF), evening primrose (EPO), and fish oil (F) as sources of linoleic acid (control), gamma-linolenic acid, and long-chain n-3 fatty acids, respectively, on cardiovascular and renal responses to chronic (5 weeks) cyclosporine administration were studied in male borderline hypertensive rats. In one experiment (n = 9/group), oral administration of CsA at 0.1 mg/kg.day significantly increased awake systolic blood pressure vs. placebo in SAF-fed rats (P less than 0.01). This increase was prevented by both EPO (P less than 0.001) and F (P less than 0.01), in the absence of group differences in body weight gain or plasma electrolyte levels. In a second experiment, CsA also increased blood pressure vs. placebo in SAF-fed rats (P less than 0.001). While this increase was prevented by EPO (P less than 0.001), F had no significant effect. Differences in group blood pressure responses were not explained by group differences in body weight gain or trough levels of blood CsA. Renal function, assessed in anesthetized rats after week 5, demonstrated a CsA-related (10 mg/kg.day) decrease in whole-kidney GFR in SAF-fed animals vs. placebo (P less than 0.05) that was prevented by EPO and attenuated by F. EPO and F also tended to reduce the CsA-induced elevation in renovascular resistance, but this difference did not reach statistical significance. These findings suggest the potential of dietary EPO and F to offset nephrotoxic effects of CsA administration, and suggest that EPO may also be useful in countering CsA-induced hypertension.

Selective population chemotherapy among schoolchildren in Beheira governorate: the UNICEF/Arab Republic of Egypt/WHO Schistosomiasis Control Project

Selective population chemotherapy using a single dose of praziquantel (40 mg per kg body weight), which was offered to 29,365 schoolchildren in Abu El Matameer and 40,241 in Abo Homos districts, Beheira governorate in the Nile delta, reduced the prevalence of schistosomiasis from 75.4% to 40.9% (reduction of 45.8%) and from 80.5% to 30.8% (reduction of 61.7%), respectively. Of those with only S. mansoni infection, 10.6% before treatment and 1.7% one year later had more than 800 eggs per gram of faeces. The prevalence of S. haematobium in Abu El Matameer was reduced from 35.4% to 7.4% after a single treatment. Infections with both S. mansoni and S. haematobium were reduced by more than 90% after one year. These reductions in prevalence and intensity of schistosomiasis in the face of continuing transmission and water contact augur well for the future role of chemotherapy in control programmes.

Comparison of the Teesdale glass sandwich and Kato-Katz techniques for the diagnosis of Schistosoma mansoni: a double-blind study

In a double blind study, the Teesdale glass sandwich and Kato-Katz techniques were compared for the diagnosis of Schistosoma mansoni. From each of five stool specimens, six slide preparations were made by each method, and each slide was read independently by two readers. Examination of the differences in the number of eggs per slide by Analysis of Variance (ANOVA) showed no significant differences between methods, readers, or slides prepared from the same specimen at the 90% level of significance.

Control of morbidity due to Schistosoma haematobium on Pemba Island: egg excretion and hematuria as indicators of infection

The variability of Schistosoma haematobium egg excretion using a quantitative syringe filtration technique and the variability of hematuria detected visually and by reagent strips were studied in a population of 520 subjects from the village of Pujini (Pemba Island, Zanzibar, Tanzania) for 6 consecutive days. A high degree of day-to-day variability of egg excretion within subjects was found both in the whole population and in the 5-19 year age group. Subjects with 1 urinary egg count of greater than or equal to 50 eggs/10 ml urine were not similarly classified in 36-61% of the other 5 examinations and 4-16% of their other examinations were negative. Gross hematuria had a specificity of almost 100%, when related to a positive filtration on any day, and was closely related to egg counts of greater than or equal to 50 eggs/10 ml urine. The finding of a strongly positive reaction for hematuria on a given single day was closely associated with the subject having a high egg count (greater than or equal to 50 eggs/10 ml urine) on at least one of the 6 days of the study. At the primary health care level, single highly positive semiquantitative values for hematuria were a more useful diagnostic indicator than a single egg count to select patients with heavy infections for selective population chemotherapy.

Metrifonate in the control of urinary schistosomiasis in Zanzibar

Selective population chemotherapy using three doses of metrifonate (7.5 mg/kg body weight each time) at two-week intervals was assessed in an entire community in Kinyasini district in Zanzibar, United Republic of Tanzania. The objectives of the study were to (1) reduce the prevalence of heavy infections (defined as greater than or equal to 50 S. haematobium eggs per 10 ml of urine) by 75% in two years, and (2) reduce the overall prevalence of infection by 50% in two years. A total of 4113 people were examined at least once during the two-year period. In the initial survey the highest proportion of infected individuals was in the 10-14-year age group, and in all subsequent surveys in the 5-9-year age group. The age group with the highest proportion of heavily infected individuals was 5-9 years for all surveys. The overall reduction of prevalence of infection from survey 1 to survey 4 was 52.9% and the prevalence of heavy infection was reduced by 62.2%. The conversion rates (negative to positive in two consecutive surveys) were highest in the longest interval of 12 months and the rates of reversion (positive to negative in two consecutive surveys, without a history of treatment) were highest in the shortest interval of 4 months. Some statistically significant relationships were observed between the number of doses and the egg reduction rates. However, for the egg-negative rates, no statistically significant relationship was observed. In the 4-month interval a 67.6% egg-negative rate was observed among those who took at least one dose; with the 12-month interval a 48.3% egg-negative rate was observed. Thus, selective population chemotherapy with metrifonate was shown to reduce the prevalence and intensity of infection due to S. haematobium over a 24-month period.

Control of morbidity due to Schistosoma haematobium on Pemba island; selective population chemotherapy of schoolchildren with haematuria to identify high-risk localities

In Pemba, Tanzania, 2 sequential surveys were made of the prevalence of haematuria in children (aged 5-19 years) in 52 schools, using direct observation of gross haematuria (bloody urine) and chemical reagent strips as indicators of Schistosoma haematobium infection. 24,462 children were examined in the first survey and 25,575 in the second, 6 months later. The prevalence of gross haematuria was initially 15.8% (3876 cases); 6 months later, after a single dose of praziquantel (40 mg/kg), it was only 2.4% (613 cases), a reduction of 84.9%. The total number of cases of haematuria (gross or otherwise) dropped similarly, from 13,920 (54%) to 6638 (26%), a 52.2% reduction. In towns the degree of reduction was positively correlated with the standard of water supply and sanitation available, and the initial prevalence of gross and total haematuria in schools was positively correlated with the prevalence 6 months later. The cost per person reduced from US$ 0.83 in the first survey to US$ 0.48 in the second (excluding field staff wages paid in local currency), the reduction being due to the reduced number of positive persons. This study has demonstrated the feasibility of using indirect techniques on a large scale for the diagnosis of S. haematobium infection to identify schoolchildren requiring treatment, and to monitor its impact on clinical morbidity in a highly endemic area.

Control of morbidity due to Schistosoma haematobium on Pemba Island: programme organization and management

A programme to control urinary schistosomiasis was initiated on Pemba island in January 1986 with the objectives of eliminating morbidity due to S. haematobium by utilizing a primary health care approach of strengthening the existing health care delivery system and creating a sound basis for future control of other parasitic and communicable diseases. The plan of action included training of rural health assistants to undertaken an intervention phase targeted to schools for selective population chemotherapy surveys at six-month intervals during the first two years, using indirect diagnostic techniques (observation of gross haematuria and detection of microscopic haematuria by chemical reagent strips) to identify individuals for treatment with praziquantel at a dose of 40 mg/kg body weight. The evaluation of the indirect techniques indicated that both sensitivity and specificity of the chemical reagent strips to detect infection were greater than 90%. After three selective population chemotherapy surveys, the prevalence of gross haematuria was reduced by 94.2% (15.8% to 0.9%) and both gross and microscopic haematuria were reduced by 76.4% (54.1% to 12.8%) among school children. Community involvement and health education were stressed in this programme. The use of dispensary laboratories to maintain control of urinary schistosomiasis is now being evaluated.

Operational studies on the control of Taenia solium taeniasis/cysticercosis in Ecuador

A large-scale study in Loja and El Oro Provinces, Ecuador, demonstrated that population-based treatment of human taeniasis with a low dose of praziquantel is feasible and effective for the short-term control of transmission of Taenia solium in hyperendemic areas. Chemotherapeutic intervention also effectively promoted local preventive measures and contributed greatly to the elaboration of a long-term control programme.

Multicentre clinical trials of benzimidazole-carbamates in human cystic echinococcosis (phase 2)

A multicentre study which constituted the second phase of trials of the efficacy of albendazole and mebendazole in human cystic echinococcosis was coordinated by WHO. A total of 112 patients from four clinical centres in Beirut, Paris, Rome and Sofia completed standardized dosage of regimens of each drug and 68 patients were followed up for at least 12 months after treatment. Albendazole was more effective than mebendazole and adverse reactions were comparable with both treatment regimens. At least 12 months is needed after treatment for an objective evaluation of the efficacy of benzimidazoles. At present, treatment with albendazole or mebendazole should be reserved for inoperable cases of cystic echinococcosis (under strict medical supervision) and individualized according to the patient's response and the occurrence and severity of adverse reactions.

The transmission potential of monkeypox virus in human populations

Data on monkeypox in Zaire over the five years 1980-1984 are analysed to assess the protection imparted by past smallpox vaccination and the transmission potential of the virus in unvaccinated communities. Attack rates in individuals with and without vaccination scars indicated that smallpox vaccination (discontinued in 1980) imparted approximately 85% protection against monkeypox. It is predicted that monkeypox virus will continue to be introduced into human communities from animal sources, and that the average magnitude and duration of monkeypox epidemics will increase as vaccine-derived protection declines in the population. On the other hand, current evidence indicates that the virus is appreciably less transmissible than was smallpox, and that it will not persist in human communities, even in the total absence of vaccination. The findings thus support the recommendation of the Global Commission for the Certification of Smallpox Eradication to cease routine smallpox vaccination in monkeypox endemic areas, but to encourage continued epidemiological surveillance.

Stochastic model for interhuman spread of monkeypox

With the eradication of smallpox, systematic routine vaccination with vaccinia has ceased and an increasing proportion of the human population in tropical rain forest areas of central and western Africa lacks vaccinia-derived immunity to monkeypox virus. This raises the question of the ability of monkeypox virus to establish and maintain itself in an unvaccinated population through continuous man-to-man transmission. A computerized stochastic model of Monte Carlo type was constructed to assess this potential risk. Simulated series were repeated 100 times to obtain distributions of predicted outcomes for decreasing levels of vaccination coverage (70 per cent, 50 per cent, and 0 per cent). The results revealed a substantial increase in new secondary cases in the total absence of vaccinia-induced immunity. Nevertheless, none of the simulated series did lead to an "explosive" epidemic. The model clearly indicated diminishing numbers of cases in successive generations and eventual cessation of transmission. Therefore, it appears highly improbable that the virus could maintain itself permanently in communities by interhuman transmission. After the eradication of smallpox, human monkeypox constitutes the most important orthopoxvirus infection in man, but analysis of information collected up to this time suggests that it does not represent currently a serious public health problem or a challenge to the achieved eradication of smallpox.

Collaborative study on antigens for immunodiagnosis of Schistosoma japonicum infection

Six research laboratories in Australia, Japan, the Philippines and the USA participated in a collaborative evaluation of immunodiagnostic tests for Schistosoma japonicum infections. The serum bank consisted of 385 well-documented sera from Brazil, Kenya, Philippines, Republic of Korea and Europe. Twelve S. japonicum antigen/test system combinations were evaluated.Crude S. japonicum egg antigens showed the highest sensitivity and specificity. The defined or characterized antigens showed no advantage over the crude antigens. Quantitative seroreactivity of all S. japonicum antigens showed a positive correlation with faecal egg counts (log x + 1) in all age groups. The performance of the circumoval precipitin test was satisfactory within the same laboratory but with differences in the results between laboratories. A monoclonal antibody used in a competitive radioimmunoassay test system performed as well as the crude egg antigens.The high sensitivity of crude S. japonicum antigens now permits further evaluation for wide-scale use in public health laboratories of endemic areas to support control efforts.

Multicentre clinical trials of benzimidazolecarbamates in human echinococcosis

Studies coordinated by the World Health Organization were conducted in seven clinical centres on the chemotherapy of human echinococcosis with mebendazole, albendazole, and flubendazole. The first phase of these ended with the following conclusions.Treatment of 85 patients with mebendazole for cystic (Echinococcus granulosus) echinococcosis was successful in 8 patients and partially successful in 4 others. Flubendazole was effective in only one case of lung echinococcosis. Albendazole was successful in 5 of 30 patients treated and partially successful in 4 others. Further studies on new drugs or new formulations of existing benzimidazoles and on better forms of their application are needed. In the mean time, chemotherapy of human cystic echinococcosis should be restricted to inoperable cases.In 54 patients with E. multilocularis echinococcosis, it was confirmed that mebendazole therapy may arrest the development of the lesions. This treatment is therefore indicated in most cases of alveolar echinococcosis with or without surgery. However, further studies are needed to clarify the optimal regimen for mebendazole treatment and to explore the effectiveness of albendazole therapy.

Effect of praziquantel on hematuria and proteinuria in urinary schistosomiasis

In five settlements on Lake Volta, Ghana, 230 persons infected with S. haematobium were treated with either 30 or 40 mg/kg of praziquantel. Both treatment regimes gave similar overall cure rates (60%) and reduction in geometric mean egg counts (92%) at a six-month follow-up. In this highly endemic area, 32% of the initial urine specimens were visibly bloody and only 4% remained bloody after treatment. Geometric mean egg counts of visibly bloody urine specimens were two to six times higher than normal appearing urine specimens. In children under 15 years of age, gross hematuria was reduced by 91% and hematuria as detected by reagent strips was reduced by 77% after treatment with praziquantel. Among adults, gross hematuria was reduced by 76% and hematuria as detected by reagent strips was reduced by 68%. Reduction was observed in 74% of all persons with 100 mg of protein/100 ml of urine or more prior to treatment. The cure rate with praziquantel was only 36.1% in children who had visibly bloody urine specimens associated with high geometric mean egg counts prior to treatment. The lowest cure rate (15.4%) was observed in persons with persistent hematuria and proteinuria after treatment although the geometric mean urinary egg count was reduced 84%. In infected individuals without hematuria or proteinuria prior to treatment, the cure rate was 96%. This study demonstrated that praziquantel reduced clinical signs due to S. haematobium infection as well as achieved a high cure rate and/or reduction of egg excretion. Conversely, individuals with clinical signs of hematuria and proteinuria had a lower cure rate with praziquantel than individuals without clinical signs.