Sodium hypochlorite dosage for household and emergency water treatment: updated recommendations

Household water treatment with chlorine can improve the microbiological quality of household water and reduce diarrheal disease. We conducted laboratory and field studies to inform chlorine dosage recommendations. In the laboratory, reactors of varying turbidity (10-300 NTU) and total organic carbon (0-25 mg/L addition) were created, spiked with Escherichia coli, and dosed with 3.75 mg/L sodium hypochlorite. All reactors had >4 log reduction of E. coli 24 hours after chlorine addition. In the field, we tested 158 sources in 22 countries for chlorine demand. A 1.88 mg/L dosage for water from improved sources of <5 or <10 NTU turbidity met free chlorine residual criteria (≤2.0 mg/L at 1 hour, ≥0.2 mg/L at 24 hours) 91-94% and 82-87% of the time at 8 and 24 hours, respectively. In unimproved water source samples, a 3.75 mg/L dosage met relaxed criteria (≤4.0 mg/L at 1 hour, ≥0.2 mg/L after 24 hours) 83% and 65% of the time after 8 and 24 hours, respectively. We recommend water from improved/low turbidity sources be dosed at 1.88 mg/L and used within 24 hours, and from unimproved/higher turbidity sources be dosed at 3.75 mg/L and consumed within 8 hours. Further research on field effectiveness of chlorination is recommended.

Clinical efficacy of melittin in the treatment of cats infected with the feline immunodeficiency virus

OBJECTIVE

The bee venom melittin shows an antiviral efficacy against the human immunodeficiency virus in cell culture. It was shown to be non-toxic for cats. Aim of this pilot study was to investigate the clinical efficacy and side-effects of melittin in cats naturally infected with feline immunodeficiency virus (FIV).

MATERIAL AND METHODS

The study was performed as a prospective, placebo-controlled double-blinded trial. Twenty cats were included, of which 10 cats each were treated with either melittin (500 µg/kg body weight) or phosphate-buffered saline (placebo) subcutaneously twice per week. During the treatment period of 6 weeks, the cats' general health status, determined by the Karnofsky's score, and the severity of clinical signs (conjunctivitis and stomatitis) using a clinical scoring system were evaluated. Haematology, biochemistry profiles, lymphocyte subpopulations, CD4/CD8 ratio, and pterines (biopterine, 7-xanthopterine) as surrogate parameters were also compared.

RESULTS

The general health status and the clinical scores for conjunctivitis and stomatitis improved in cats treated with melittin. A statistically significant improvement however could only be detected for conjunctivitis in cats treated with melittin compared to cats treated with placebo which was likely due to different scores between both groups at the beginning. No influence on the lymphocyte subpopulations, CD4/CD8 ratio, and pterine concentrations was observed. No side effects occurred in this study.

CONCLUSION AND CLINICAL RELEVANCE

In the protocol used in the present study, no significant efficacy of melittin could be detected. However, efficacy of melittin, especially if applied in a higher dosage as in the present study or for a longer period, could be evaluated in further studies. Synergistic effects if used in combination with classic antiretroviral drugs could be an interesting future approach.

Economic Evidence for US Asthma Self-Management Education and Home-Based Interventions

The health and economic burden of asthma in the United States is substantial. Asthma self-management education (AS-ME) and home-based interventions for asthma can improve asthma control and prevent asthma exacerbations, and interest in health care-public health collaboration regarding asthma is increasing. However, outpatient AS-ME and home-based asthma intervention programs are not widely available; economic sustainability is a common concern. Thus, we conducted a narrative review of existing literature regarding economic outcomes of outpatient AS-ME and home-based intervention programs for asthma in the United States. We identified 9 outpatient AS-ME programs and 17 home-based intervention programs with return on investment (ROI) data. Most programs were associated with a positive ROI; a few programs observed positive ROIs only among selected populations (eg, higher health care utilization). Interpretation of existing data is limited by heterogeneous ROI calculations. Nevertheless, the literature suggests promise for sustainable opportunities to expand access to outpatient AS-ME and home-based asthma intervention programs in the United States. More definitive knowledge about how to maximize program benefit and sustainability could be gained through more controlled studies of specific populations and increased uniformity in economic assessments.

A rapid assessment of drinking water quality in informal settlements after a cholera outbreak in Nairobi, Kenya

Populations living in informal settlements with inadequate water and sanitation infrastructure are at risk of epidemic disease. In 2010, we conducted 398 household surveys in two informal settlements in Nairobi, Kenya with isolated cholera cases. We tested source and household water for free chlorine residual (FCR) and Escherichia coli in approximately 200 households. International guidelines are ≥0.5 mg/L FCR at source, ≥0.2 mg/L at household, and <1 E. coli/100 mL. In these two settlements, 82% and 38% of water sources met FCR guidelines; and 7% and 8% were contaminated with E. coli, respectively. In household stored water, 82% and 35% met FCR guidelines and 11% and 32% were contaminated with E. coli, respectively. Source water FCR≥0.5 mg/L (p=0.003) and reported purchase of a household water treatment product (p=0.002) were associated with increases in likelihood that household stored water had ≥0.2 mg/L FCR, which was associated with a lower likelihood of E. coli contamination (p<0.001). These results challenge the assumption that water quality in informal settlements is universally poor and the route of disease transmission, and highlight that providing centralized water with ≥0.5 mg/L FCR or (if not feasible) household water treatment technologies reduces the risk of waterborne cholera transmission in informal settlements.

Clinical efficacy of the acyclic nucleoside phosphonate 9-(2-phosphonylmethoxypropyl)-2,6-diaminopurine (PMPDAP) in the treatment of feline immunodeficiency virus-infected cats

In in vitro studies, the acyclic nucleoside phosphonate 9-(2-phosphonylmethoxypropyl)-2,6-diaminopurine (PMPDAP) inhibited the replication of feline immunodeficiency virus (FIV). No information about its clinical efficacy is available so far. The aim of this prospective placebo-controlled, double-blinded study was to evaluate the antiviral efficacy of PMPDAP in cats naturally infected with FIV. Twenty cats were randomly assigned to two treatment groups receiving either PMPDAP (25 mg/kg) or placebo twice per week subcutaneously for 6 weeks. The general health status (Karnofsky's score), clinical signs, laboratory, immunological, and surrogate parameters were evaluated. No significant differences were found between PMPDAP- and placebo-treated cats, although cats treated with PMPDAP showed a tendency for improvement in their Karnofsky's score and clinical signs. Haematological side effects were noted in the PMPDAP-treated cats. Thus, PMPDAP may be an option in treating cats if it becomes available for veterinarians, but side effects have been monitored.

Persistence and leaching of imazethapyr and flumetsulam herbicides over a 4-year period in the highly alkaline soils of south-eastern Australia

Imazethapyr and flumetsulam are acetolactate synthase herbicides commonly used in the cereal belt of south-eastern Australia. As their labels recommend recropping periods of up to 34 months for imazethapyr and 24 months for flumetsulam, there are concerns that in some cases their persistence may damage subsequent rotation crops. This is the first major study in south-eastern Australia to investigate their leaching and persistence for up to 4 years after treatment. Imazethapyr persisted for more than 3 years at 2 sites and flumetsulam for more than 2 years at 3 sites. For imazethapyr, soil type (clay content) rather than soil pH seemed to be most important in determining persistence, with residues of 10% of applied imazethapyr predicted to persist for 24 months after treatment in clay soil and 5 months after treatment in sandy soil. The potential for leaching below our studied soil depth of 40 cm is of concern for imazethapyr but not for flumetsulam. The current labels appear to provide adequate information for safe recropping periods, but may be conservative for imazethapyr in sandy soils.

Persistence and leaching of sulfonylurea herbicides over a 4-year period in the highly alkaline soils of south-eastern Australia

The sulfonylurea herbicides are commonly used in the cereal belt of south-eastern Australia and there is concern that their persistence in alkaline soils is long enough to damage subsequent rotational crops such as legumes and oilseeds. In this study, we investigated leaching and persistence of 3 commonly used herbicides (chlorsulfuron, triasulfuron and metsulfuron-methyl) in alkaline soils of south-eastern Australia (pH range 7.4–8.6) for at least 4 years after treatment. In general, chlorsulfuron was predicted to persist for 3–5 years [time to degrade to 1% (DT99) of 33–63 months after treatment depending on the field site], triasulfuron for 1–3 years (DT99 of 13–37 months after treatment), and metsulfuron-methyl for less than 1 year (although data were insufficient for degradation estimates) after its application. However, this varied between sites and years of application. Although, the majority of residues remained in the top 20 cm of the soil profile throughout the study, leaching of a small fraction of the residue to deeper layers of the profiles (up to 1 m) was observed. Despite their slow rate of degradation, the herbicides did eventually dissipate, even in soils with very high pH (8.5). In most cases, the current product labels provide an adequate safety period to protect sensitive rotational crops from potential damage due to excessive persistence. However, in particular years at 3 of the 5 field sites, metsulfuron-methyl and triasulfuron persisted beyond the recommended recropping period (9 months for metsulfuron-methyl and 22 months for triasulfuron in soils up to pH 7.5 or 24 months in soils pH 7.6 and above). An accurate measurement of soil pH and its variability within the paddock is essential to minimise any subsequent crop damage by these herbicides.

Crop damage caused by residual acetolactate synthase herbicides in the soils of south-eastern Australia

Grain growers in south-eastern Australia have reported unexpected crop failures with theoretically safe recropping periods for acetolactate synthase herbicides in alkaline soils. This experience has led to the concern that these herbicides may degrade very slowly in alkaline soils, and herbicide residues have at times been blamed for unexplained crop losses. To address this issue, we established 5 recropping trials across Victoria and South Australia with 5 acetolactate synthase herbicides (chlorsulfuron, triasulfuron, metsulfuron-methyl, imazethapyr, and flumetsulam). The herbicides were applied to separate plots in years 1, 2 or 3, and sensitive crop species were sown in year 4 to measure the impact of herbicide residues. We observed that the persistence of the sulfonylureas (chlorsulfuron, triasulfuron, metsulfuron-methyl) varied between herbicides, but all persisted longer in alkaline soils than in acid soils, and were, therefore, more likely to damage crops in alkaline soil. Imazethapyr persisted longer in clay soils than in sandy soils and was, therefore, more likely to damage crops in clay soils. All herbicides persisted longer when rainfall was below average. Canola was more sensitive to imazethapyr than either pea, lentil or medic, but was less sensitive to the sulfonylureas. In contrast, lentil and medic were the most sensitive to sulfonylureas. Despite some damage, we found that safe recropping periods could be predicted from the product labels in all but one situation. The sole exception was that metsulfuron-methyl reduced dry matter and yield of lentil and medic sown 10 months after application in a soil with pH 8.5. We hypothesise that the real cause of crop failure in many situations is not unusual herbicide persistence, but failure to take full account of soil type (pH and clay content including variation in the paddock) and rainfall when deciding to recrop after using acetolactate synthase herbicides.

Mobility and persistence of three sulfonylurea herbicides in alkaline cropping soils of south-eastern Australia

Biologically active residues of the herbicides metsulfuron-methyl, chlorsulfuron and triasulfuron were estimated with field pea bioassays in soil samples to 80 cm depth from 4 field trials in south-eastern Australia situated on neutral to highly alkaline soil. Residues were both mobile and persistent at low levels. Leaching occurred beyond the lowest sampling depth during the winter–spring growing season. Metsulfuron-methyl was the most mobile of the 3 herbicides. Plant-back experiments involving susceptible crop and pasture species on 2 of the sites showed that the rates of decline of these residues in the sampling zone were slower than might be inferred from label plant-back recommendations in 1 of 2 seasons.

Sequence analysis of a 33.1 kb fragment from the left arm of Saccharomyces cerevisiae chromosome X, including putative proteins with leucine zippers, a fungal Zn(II)2-Cys6 binuclear cluster domain and a putative alpha 2-SCB-alpha 2 binding site

In the framework of the European BIOTECH project for sequencing the Saccharomyces cerevisiae genome, we have determined the nucleotide sequence of the left part of the cosmid clone 232 and the cosmid clone 233 provided by F. Galibert (Rennes Cedex, France). We present here 33,099 base pairs of sequence derived from the left arm of chromosome X of strain S288C. This sequence reveals 17 open reading frames (ORFs) with more than 299 base pairs, including the published sequences for ARG3, LIGTR/LIG1, ORF2, ACT3 and SCP160. Two other ORFs showed similarity with S. cerevisiae genes: one with the CAN1 gene coding for an arginine permease, and one with genes encoding the family of transcriptional activators containing a fungal Zn(II)2-Cys6 binuclear cluster domain like that found in Ppr1p or Ga14p. Both putative proteins contain a leucine zipper motif, the Can1p homologue has 12 putative membrane-spanning domains and a putative alpha 2-SCB-alpha 2 binding site. In a diploid disruption mutant of ORF J0922 coding for the transcriptional activator homologue, no colonies appeared before 10 days after transformation and then grew slowly. In contrast, haploid disruption mutants showed a growth phenotype like wild-type cells. One ORF showed weak similarity to the rad4 gene product of Schizosaccharomyces pombe and is essential for yeast growth. Five ORFs showed similarity to putative genes on the right arm of chromosome XI of S. cerevisiae. Two of them have similarity to each other and belong to a family of extracellular proteins that groups mammalian SCP/Tpx-1, insects Ag3/Ag5, plants PR-1 and fungi Sc7/Sc14.(ABSTRACT TRUNCATED AT 250 WORDS)

[Clinical symptoms and diagnosis of feline infectious peritonitis]

Body effusions from 197 cats and blood serum samples from 252 cats, where Feline Infectious Peritonitis (FIP) was part of the differential diagnosis, were analysed. The diagnoses were confirmed by clinical follow up or histopathology. The final diagnosis FIP was always confirmed by histopathology. The median age of cats with FIP was 1.6 years. FIP was responsible for 41% of the body effusions, whereas malignomas caused 24%, cardial insufficiencies 14% and purulent serositis 12% of the body effusions. The rivalta test was highly sensitive for FIP. Predictive value of a negative result was 100%, predictive value of a positive result was 84%. In half of the cases with purulent serositis and in 20% of malignomas rivalta reacted positive. The cardial insufficiencies were negative for rivalta. Coronavirus antigen could be demonstrated by immunofluorescence in 34 of 49 body effusions caused by FIP, whereas in the 50 body effusions caused by other diseases no coronavirus antigen was detected. An albumin globulin ratio of < 0.6 was highly diagnostic for an inflammatory process, nearly exclusively for FIP. An albumin globulin ratio of > or = 0.8 almost excluded FIP. Only a negative or very high (1:1600) FIP titer could contribute to confirm diagnosis. Low and medium titers, however, should not be interpreted.

Mandibular form and position in 10-year-old boys

It is unclear whether malocclusion characterized by jaw discrepancy is caused by variations in mandibular position, mandibular size, or a combination of the two. To clarify the situation, the mandibular outlines of 124 10-year-old boys, equally divided among the Angle classes, were generated from cephalograms with a computer plotting technique. The mean plots for each of the groups were superimposed on S-N and Go-Gn. These showed mandibular form and size to be similar in the Class I and Class III groups and in both divisions of Class II. The position of Class III mandibles was more anterior and rotated forward in relation to the cranial base compared with the other groups. Statistical analysis confirmed these findings. There was evidence to support the idea that Class II, Division 2 malocclusion is largely a dentoalveolar rather than a skeletal entity.

High throughput grating VUV filter for the measurement of weak spectral lines in the presence of monochromatic background

The design and characteristics of an optical filter using a holographic grating in combination with a multiple entrance and exit slit arrangement are described. The instrument transmits VUV radiation at Ar(I) 106.6 nm and Kr(I) 123.6 nm while excluding the hydrogen Lyman-alpha at 121.6 nm. The transmission at 123.6 nm is approximately 10%, if averaged over the circular entrance aperture of 28-mm diameter without correcting for the blocking by the masks. The corresponding transmission at 121.6 nm is 0.0001 or less. The concept with selective blocking of one wavelength and transmission at another using a multiple slit arrangement is transferable to any line pair. The 123.6-nm grating efficiency has been assessed as 37%.

Effects of lindane treatment on drug metabolizing enzymes and liver weight of CF1 mice in which it evoked hepatomas and in non-susceptible rodents

In CF1 mice lindane treatment led to a significant increase in liver tumor incidence whilst in Osborne-Mendel rats it was not carcinogenic. Although somewhat less clear, the test in B6C3F1 mice led to the conclusion that under the conditions of the bioassay lindane was not carcinogenic for this strain. In this study, the specific activities of some enzymes which are thought to be involved in the metabolism of lindane were studied in these different strains in order to investigate whether differences exist in the activities of these enzymes. Because the enzyme pattern may change after lindane treatment during the carcinogenicity studies, we also investigated the enzyme activities in animals treated for 3 days or 3 months with various doses of lindane. The influence of lindane treatment on the relative liver weight was also determined. B6C3F1 mice showed no increase in absolute or relative liver weight even after 3 months of treatment with the highest tolerated dose of lindane. However, in the susceptible CF1 strain lindane led to a large increase of the absolute and relative liver weight in both sexes, whilst a smaller increase was observed in Osborne-Mendel rats. Basal glutathione-S-transferase activity was higher in males than in females in all three strains, bearing no apparent relationship to susceptibility for tumor formation. However, after treatment with the highest dose of lindane a 5-6-fold induction of this enzyme activity was observed in female CF1 mice, which then together with the male CF1 mice had a higher glutathione-S-transferase activity than untreated and treated B6C3F1 mice and Osborne-Mendel rats. Whether lindane or one of its metabolites is activated by conjugation with glutathione remains to be established. After treatment of the animals with high doses of lindane detergent-treated rat liver microsomes showed a higher UDP-glucuronosyltransferase activity than mouse liver microsomes. This high activity could lead to a rapid conjugation of phenols derived from lindane. The most striking difference observed in this study was the fact that together with the larger increase in absolute and relative liver weight, untreated and treated CF1 mice showed higher monooxygenase activity and, after treatment with lindane, lower epoxide hydrolase activity than rats. Whether the high monooxygenase and rather low epoxide hydrolase activity will lead to an accumulation of reactive epoxides derived from lindane remains to be clarified.