Rotation of treatments between spinosad and amitraz for the control of Rhipicephalus (Boophilus) microplus populations with amitraz resistance

A farmlet study was conducted over 4 years in which three treatments were applied to six groups of Holstein dairy calves. Calves in each group were infested with equal numbers of N-strain (susceptible) and Ultimo strain (amitraz and synthetic pyrethroid resistant) tick larvae to establish self-sustaining populations with an initial, measurable level of resistance to amitraz. Standard counts of all ticks between 4.5 and 8.0 mm diameter on one side of each animal were made each week and treatment was applied when tick numbers exceeded a threshold of 25 engorged adults per side. The three treatments were: 1, spinosad spray whenever tick numbers exceeded the threshold; 2, amitraz spray whenever tick numbers exceeded the threshold; 3, spinosad whenever tick numbers exceeded the threshold for the first 2 months, then amitraz for 2 months, with alternation every subsequent 2 months. Engorged adult female ticks were collected from each treatment group on 10 or 11 occasions during the study and tested using the larval packet test bioassay (LPT) for acaricide resistance. Spinosad 250 ppm provided effective control of amitraz-resistant tick populations in the field, using a similar number of treatments as in the amitraz and rotation groups. The initial infestations of all of the groups resulted in the establishment of populations with in vitro evidence of resistance to amitraz using the LPT. Treatment with spinosad or with a rotation between spinosad and amitraz every 2 months resulted in reduced levels of resistance to amitraz according to the LPT. The animals treated with amitraz alone showed increasing resistance to amitraz according to the LPT each summer and autumn with a return to full or almost full susceptibility to amitraz in early spring in all years. This pattern suggests a relative lack of fitness of amitraz-resistant ticks that might be exploited by using an acaricide rotation strategy

Point of care HbA1c level for diabetes mellitus management and its accuracy among tuberculosis patients: a study in four countries

BACKGROUND: Diabetes mellitus (DM) is common among tuberculosis (TB) patients and often undiagnosed or poorly controlled. We compared point of care (POC) with laboratory glycated haemoglobin (HbA1c) testing among newly diagnosed TB patients to assess POC test accuracy, safety and acceptability in settings in which immediate access to DM services may be difficult. METHODS: We measured POC and accredited laboratory HbA1c (using high-performance liquid chromatography) in 1942 TB patients aged 18 years recruited from Peru, Romania, Indonesia and South Africa. We calculated overall agreement and individual variation (mean ± 2 standard deviations) stratified by country, age, sex, body mass index (BMI), HbA1c level and comorbidities (anaemia, human immunodeficiency virus [HIV]). We used an error grid approach to identify disagreement that could raise significant concerns. RESULTS: Overall mean POC HbA1c values were modestly higher than laboratory HbA1c levels by 0.1% units (95%CI 0.1–0.2); however, there was a substantial discrepancy for those with severe anaemia (1.1% HbA1c, 95%CI 0.7–1.5). For 89.6% of 1942 patients, both values indicated the same DM status (no DM, HbA1c <6.5%) or had acceptable deviation (relative difference <6%). Individual agreement was variable, with POC values up to 1.8% units higher or 1.6% lower. For a minority, use of POC HbA1c alone could result in error leading to potential overtreatment (n = 40, 2.1%) or undertreatment (n = 1, 0.1%). The remainder had moderate disagreement, which was less likely to influence clinical decisions. CONCLUSION: POC HbA1c is pragmatic and sufficiently accurate to screen for hyperglycaemia and DM risk among TB patients