Long-term Follow-up of Patients With Lyme Disease: Longitudinal Analysis of Clinical and Quality-of-life Measures.

BACKGROUND: Lyme disease is the most common vector-borne disease in the United States. Some patients report persistent or intermittent subjective symptoms of mild to moderate intensity after antibiotic treatment for Lyme disease. We sought to evaluate trends in clinical and quality-of-life (QOL) measures in a cohort of patients with Lyme disease enrolled in a natural history study at the National Institutes of Health from 2001-2014. METHODS: QOL was measured using the self-administered 36-item Short Form Health Survey (SF-36) during study follow-up. Primary outcomes included mean physical (PCS) and mental (MCS) health QOL composite scores and reporting long-term (≥2 years) symptoms, adjusted for Lyme disease stage and severity at diagnosis. RESULTS: Overall, 101 patients with an average follow-up time of 3.9 years (range, 0.5-11.3 years) were included. At first visit, overall mean QOL scores were below the US population mean for both PCS (45.6 ± 10.4) and MCS (47.3 ± 11.5) but increased to just above the national average after 3 years of follow-up for both PCS (50.7 ± 9.6) and MCS (50.1 ± 10.0). Baseline QOL scores were lowest in those with late disease (P < 0.01) but also increased by the end of follow-up to national averages. In multivariate analysis, the only factors significantly associated with long-term symptoms or lower QOL scores were other comorbidities unrelated to Lyme disease. CONCLUSIONS: Comorbid conditions can play a role in the reporting of long-term symptoms and overall QOL of Lyme disease patients and should be considered in the evaluation of these patients. CLINICAL TRIALS REGISTRATION: NCT00028080.

Estimation of insecticide persistence, biological activity and mosquito resistance to PermaNet® 2 long-lasting insecticidal nets over three to 32 months of use in Ethiopia.

BACKGROUND: Information is needed on the expected durability of insecticidal nets under operational conditions. The persistence of insecticidal efficacy is important to estimate the median serviceable life of nets under field conditions and to plan for net replacement. METHODS: Deltamethrin residue levels were evaluated by the proxy method of X-ray fluorescence spectrometry on 189 nets used for three to six months from nine sites, 220 nets used for 14-20 months from 11 sites, and 200 nets used for 26-32 months from ten sites in Ethiopia. A random sample of 16.5-20% of nets from each time period (total 112 of 609 nets) were tested by bioassay with susceptible mosquitoes, and nets used for 14-20 months and 26-32 months were also tested with wild caught mosquitoes. RESULTS: Mean insecticide levels estimated by X-ray fluorescence declined by 25.9% from baseline of 66.2 (SD 14.6) mg/m2 at three to six months to 44.1 (SD 21.2) mg/m2 at 14-20 months and by 30.8% to 41.1 (SD 18.9) mg/m2 at 26-32 months. More than 95% of nets retained greater than 10 mg/m2 of deltamethrin and over 79% had at least 25 mg/m2 at all time periods. By bioassay with susceptible Anopheles, mortality averaged 89.0% on 28 nets tested at three to six months, 93.3% on 44 nets at 14-20 months and 94.1% on 40 nets at 26-32 months. With wild caught mosquitoes, mortality averaged 85.4% (range 79.1 to 91.7%) at 14-20 months but had dropped significantly to 47.2% (39.8 to 54.7%) at 26-32 months. CONCLUSIONS: Insecticide residue level, as estimated by X-ray fluorescence, declined by about one third between three and six months and 14-20 months, but remained relatively stable and above minimum requirements thereafter up to 26-32 months. The insecticidal activity of PermaNet® 2.0 long-lasting insecticidal nets in the specified study area may be considered effective to susceptible mosquitoes at least for the duration indicated in this study (32 months). However, results indicated that resistance in the wild population is already rendering nets with optimum insecticide concentrations less effective in practice.

Physical durability of PermaNet 2.0 long-lasting insecticidal nets over three to 32 months of use in Ethiopia.

BACKGROUND: Ethiopia scaled up net distribution markedly starting in 2006. Information on expected net life under field conditions (physical durability and persistence of insecticidal activity) is needed to improve planning for net replacement. Standardization of physical durability assessment methods is lacking. METHODS: Permanet®2.0 long-lasting insecticidal bed nets (LLINs), available for distribution in early 2007, were collected from households at three time intervals. The number, size and location of holes were recorded for 189 nets used for three to six months from nine sites (2007) and 220 nets used for 14 to 20 months from 11 sites (2008). In 2009, a "finger/fist" sizing method classified holes in 200 nets used for 26 to 32 months from ten sites into small (<2 cm), medium (> = 2 to < =10 cm) and large (>10 cm) sizes. A proportionate hole index based on both hole number and area was derived from these size classifications. RESULTS: After three to six months, 54.5% (95% CI 47.1-61.7%) of 189 LLINs had at least one hole 0.5 cm (in the longest axis) or larger; mean holes per net was 4.4 (SD 8.4), median was 1.0 (Inter Quartile Range [IQR] 0-5) and median size was 1 cm (IQR 1-2). At 14 to 20 months, 85.5% (95% CI 80.1-89.8%) of 220 nets had at least one hole with mean 29.1 (SD 50.1) and median 12 (IQR 3-36.5) holes per net, and median size of 1 cm (IQR 1-2). At 26 to 32 months, 92.5% of 200 nets had at least one hole with a mean of 62.2 (SD 205.4) and median of 23 (IQR 6-55.5) holes per net. The mean hole index was 24.3, 169.1 and 352.8 at the three time periods respectively. Repairs were rarely observed. The majority of holes were in the lower half of the net walls. The proportion of nets in 'poor' condition (hole index >300) increased from 0% at three to six months to 30% at 26 to 32 months. CONCLUSIONS: Net damage began quickly: more than half the nets had holes by three to six months of use, with 40% of holes being larger than 2 cm. Holes continued to accumulate until 92.5% of nets had holes by 26 to 32 months of use. An almost complete lack of repairs shows the need for promoting proper use of nets and repairs, to increase LLIN longevity. Using the hole index, almost one third of the nets were classed as unusable and ineffective after two and a half years of potential use.