Characterization of acaricide resistance in Rhipicephalus microplus populations infesting cattle in northeastern India and assessment of local plant extracts for tick management.

In the present study, the tick isolates were collected from Assam state, of northeastern region (NER) and characterized using in vitro bioassay, biochemical and molecular assays. Comparing LC50 value of susceptible IVRI-I and larvae of field isolates, revealed that RF against deltamethrin was highest for Morigaon (MGN = 21.8) and lowest for Sonitpur (SNP = 3.3) isolate. The RF against cypermethrin was highest for Nagaon (NGO = 5.0) and lowest for Barpeta (BPT = 1.2) isolate. Against coumaphos, the highest RF of 4.5 was calculated for BPT (4.5) and lowest for NGO (1.3) isolate. While using adults based assay, highest RF of 24.68 against deltamethrin and lowest RF of 4.96 was determined for MGN and SNP isolate, respectively. In contrast to the results obtained using larvae, against cypermethrin, highest RF was recorded for Kamrup Metropolitan (KMP) while it was NGO isolate using larvae. In case of coumaphos, both larvae and adults of BPT isolate were also highly resistant and lowest RF was detected in SNP (2.30) isolate. All the isolates were susceptible to ivermectin. A significant correlation (p < 0.01) between deltamethrin resistance and higher expression of glutathioneS-transferase was observed while no correlation with esterase and monooxygenase enzymes activity was noted. For the development of possible ecofriendly control measure, different accessions of Argemone mexicana and Datura metel plant species were collected, extracted and screened against adult ticks. Two accessions, NEA-03 and NED-06 collected from Amlighat and Diphu (East Karbi Anglong) were more than 90 % effective. Further dose response study of these accessions determined the LC50 values of 4.86 and 3.96 %, respectively.The resistance status of the collected tick isolates was compared with the data generated from other regions having higher livestock population and possibility of exploitation of identified plant species for the development of natural antitick product is discussed.

Comparative impact of coumaphos, amitraz and plant extract of Ageratum conyzoides on the oogenesis of Rhipicephalus microplus.

The present experiment was conducted to evaluate and compare the impact of Ageratum conyzoides plant extract (ACE) with routinely used synthetic acaricides i.e., amitraz and coumaphos on the oogenesis of engorged adult females of Rhipicephalus microplus tick. On the day of dropping from the host, panoistic ovary of R. microplus appeared white in colour, horseshoe shaped, hollow tubular organ with immature oocytes predominantly in dorsal groove. Different developmental stages of oocytes (I-V) proceed simultaneously and asynchronously. Oocytes showed gradual increase in size, deep brown colored with accumulation of eggs in oviduct during 24-72 hours of development.At LC90 concentration a highly significant (p < 0.001) cessation of egg laying after exposure to amitraz and ACE while significant reduction (p < 0.01) of egg laying in coumaphos treated ticks was observed. Upon dissection of treated ticks, uterus and oviduct packed with eggs, which failed to pass out was observed. The histo-architectural alterations including presence of extensive vacuolation, alteration of oocyte morphology, deformation of chorion and disorganization of yolk granules were observed in the treated ovaries. Histochemically, low level of storage or synthesis of essential elements viz., proteins, polysaccharides and lipids in treated oocytes responsible for reduction of fertility and inhibition of progress of vitellogenesis was observed.

Chemo-profiling and bioassay of phytoextracts from Ageratum conyzoides for acaricidal properties against Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) infesting cattle and buffaloes in India.

In India, Rhipicephalus (Boophilus) microplus populations have developed a certain level of resistance to most of the acaricides marketed against tick species. To manage the problem, the present study was undertaken to evaluate the acaricidal potential of Ageratum conyzoides plants against acaricides-resistant ticks infesting cattle and buffaloes. The regression analysis of dose-response data of ethanolic extract of A. conyzoides revealed LC90 value of 8.91% against reference susceptible IVRI-1 line of R.(B.) microplus. The ethanolic extract was found efficacious against 76.7-90% acaricides-resistant field ticks and adversely affected oviposition showing 7.04-31.3% reduction in egg laying capacity. The extract was also showed an in vitro efficacy of 52.5 and 76.7% against reference resistant IVRI-4 and 5 lines. The GC/MS/MS profiling of hexane extract, two bioactive sub-fractions and essential oils revealed the presence of 6,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran (precocene II) as a major phyto-compound. The bioactive sub-fractions showed 96.2-97.5% efficacy against larvae of IVRI-1 and 77.1-94.9% against multi-acaricide resistant larvae of IVRI-5 line of R.(B.) microplus. The results of this study provided significant support for the development of a phyto-formulation based on A. conyzoides species.

Effect of Phototherapy on the Reliability of Transcutaneous Bilirubin Devices in Term and Near-Term Infants: A Systematic Review and Meta-Analysis.

BACKGROUND: Transcutaneous bilirubin (TcB) devices are commonly used for screening of hyperbilirubinemia in term and near-term infants not exposed to phototherapy. However, the accuracy of TcB devices in infants exposed to phototherapy is unclear. OBJECTIVES: To conduct a systematic review of studies comparing TcB devices with total serum bilirubin (TSB) in infants receiving phototherapy or in the postphototherapy phase. METHODS: MEDLINE, EMBASE, Cochrane Library, CINAHL and Scopus databases (from inception to May 8, 2014) were searched. Additional citations were identified from the bibliography of selected articles and from the abstracts of conference proceedings. The studies were included if they compared TcB results with TSB in term and near-term infants during phototherapy or after discontinuation of phototherapy. Two reviewers independently assessed studies for inclusion, and discrepancies were resolved with consensus. Risk of bias was assessed using the QUADAS-2 tool. RESULTS: Fourteen studies were identified. The pooled estimates of correlation coefficients (r) during phototherapy were: covered sites 0.71 (95% CI 0.64-0.77, 11 studies), uncovered sites 0.65 (95% CI 0.55-0.74), 8 studies), forehead 0.70 (95% CI 0.64-0.75, 12 studies) and sternum 0.64 (95% CI 0.43-0.77, 5 studies). Two studies also provided results as Bland-Altman difference plots (mean TcB-TSB differences -29.2 and 30 µmol/l, respectively). The correlation coefficient improved marginally in the postphototherapy phase (r = 0.72, 95% CI 0.64-0.78, 4 studies). CONCLUSION: We found a moderate correlation between TcB and TSB during phototherapy with a marginal improvement in the postphototherapy phase. Further research is needed before the use of TcB devices can be recommended for these settings.

In vitro acaricidal properties of Semecarpus anacardium fruit and Datura stramonium leaf extracts against acaricide susceptible (IVRI-I line) and resistant (IVRI-V line) Rhipicephalus (Boophilus) microplus.

In an attempt to identify plants having anti-tick properties, the 95% ethanolic and 50% hydro-ethanolic extracts of the fruits of Semecarpus anacardium and leaves of Datura stramonium were evaluated against reference tick lines of Rhipicephalus (Boophilus) microplus. The 95% ethanolic extracts of S. anacardium and D. stramonium caused 50% and 20% mortality, respectively, within 72 h of treatment by adult immersion test. The LC90 value of the ethanolic fruit extract of S. anacardium was determined as 13.5% (CI 12.05-15.12). The extract was also found efficacious (73.3%±3.3%) against the multi-acaricide-resistant IVRI-V line of R.(B.) microplus. The S. anacardium extract significantly affected the reproductive physiology of treated ticks by inhibiting the oviposition and was found safe. The HPTLC fingerprinting profile revealed the presence of pyrocatechol as a marker compound. The acaricidal property of S. anacardium against chemical acaricide-resistant R. (B.) microplus was discussed.

Reliability of transcutaneous bilirubin devices in preterm infants: a systematic review.

BACKGROUND AND OBJECTIVE: Transcutaneous bilirubin (TcB) devices are widely used for the estimation of serum bilirubin levels in term and near-term infants. Our objective was to review the diagnostic accuracy of TcB devices in preterm infants. METHODS: Medline, Embase, Cochrane library, Cumulative Index to Nursing and Allied Health Literature, and Scopus were searched (from database inception date until December 2012). Additional citations were identified by using the bibliographies of selected articles and from conference proceedings. The studies were included if they compared TcB with total serum bilirubin in preterm infants before phototherapy and presented data as correlation coefficients or as Bland-Altman difference plots. Data were extracted by 1 reviewer and checked for accuracy by the second reviewer. An assessment tool (quality assessment of diagnostic accuracy studies) was used for risk of bias assessments. RESULTS: Twenty-two studies met the inclusion criteria; 21 studies reported results as correlation coefficients, with pooled estimates of r = 0.83 for each site of measurement. Pooled estimates in infants <32 weeks' gestation were similar to the overall preterm population (r = 0.89 [95% confidence interval: 0.82-0.93]). For the 2 commonly used TcB devices (ie, JM103 and BiliCheck), the results were comparable at the forehead site, although the JM103 device exhibited better correlation at the sternum. Analysis of the Bland-Altman plots (13 studies) revealed negligible bias in measurement at the forehead or sternum site by using either the JM-103 or BiliCheck device; however, the JM-103 device exhibited better precision than the BiliCheck (SD for TcB - total serum bilirubin differences: 24.3 and 31.98 µmol/L, respectively). CONCLUSIONS: The TcB devices reliably estimated bilirubin levels in preterm infants and could be used in clinical practice to reduce blood sampling.