Deltamethrin resistance in south Indian isolates of Rhipicephalus (Boophilus) microplus.

The present communication deals with the detection and characterization of deltamethrin resistance in tick populations using biological (larval packet test), biochemical (esterase enzyme assay) and molecular assays. Ticks were collected from cattle farms of Korutla, Telangana (KOR), Mehboob Nagar, Telangana (MBN), Nagpur, Maharashtra (NAG), Parbani, Maharashtra (PBN), Madhavaram, Tamil Nadu (MAD), Cuddalore, Tamil Nadu (CUD), Sakhleshpur, Karnataka (SAK) and Buvenduvella, Karnataka (BUV). Out of eight field isolates, seven were identified as Rhipicephalus (Boophilus) microplus while one isolate (CUD) was identified as R. (B.) annulatus. The LC50 values and resistance factors (RF) of field isolates were assessed by larval packet test (LPT). RF values of two isolates viz., Korutla and Parbhani (KOR, PAR) were close to that of reference susceptible isolate. R. (B.) microplus isolate from Nagpur (NAG) and Sakleshpur (SAK) revealed slightly higher RF values (6.42 and 4.51). They revealed slightly elevated esterase enzyme activity too. Other isolates did not reveal higher values for RF or esterase activity. Previously identified mutations conferring synthetic pyrethroid resistance in R. (B.) microplus populations were analysed by sequencing the mutation flanking regions of the carboxyl esterase and the sodium channel genes (domain III S6 and domain II S4-5 linker region). However, these point mutations were not detected in the field isolates. The results of the present study revealed that low levels of synthetic pyrethroid resistance had developed in field populations of ticks of southern India.

Histoarchitecture of ovary of Haemaphysalis bispinosa during engorgement period.

The ovary of Haemaphysalis bispinosa was of panoistic type with asynchronous development of oocytes. The wall of the ovary was composed of a layer of epithelial cells to which the oocytes were attached by means of pedicel cells with elongated nucleus. The oocytes were classified into stages I to V based on morphologic characteristics like size and shape, presence / absence of germ vesicle, cytoplasmic appearance, presence or absence of yolk granules and presence of chorion. Day wise changes were in the form of occurrence of oogonia from partially fed upto day zero of engorgement, presence of all stages of oocytes on day one and two after engorgement and onset of degenerative changes in oocytes from day three onwards. Degeneration was complete on day eight with the appearance of polymorphism, vacuolation, cytoplasmic blebbing and autophagic activity in oocytes.

Phylogenetic analysis of bovine Theileria spp. isolated in south India.

The objective of the present study is to determine the phylogenetic position of the Theileria organisms in blood of cattle of southern India using molecular tools. Theileria annulata (Namakkal isolate, Tamil Nadu) and three Theileria field isolates (free of T. annulata) from Wayanad, Kerala (Wayanad 1, 2, 3) were used. The small subunit ribosomal RNA (SSU rRNA) and major piroplasm surface protein (MPSP) gene products were cloned, sequenced and the phylogenetic tree constructed. SSU rRNA gene of Wayanad 1 isolate (JQ706077) revealed maximum identity with Theileria velifera or Theileria cervi. The phylogenetic tree constructed based on SSU rRNA genes revealed that Wayanad 1 isolate belonged to a new type which share common ancestor with all the other theilerial species while Wayanad 2 and 3 isolates (JX294459, JX294460) were close to types A and C respectively. Based on MPSP gene sequences, Wayanad 2 and 3 (JQ706078, JX648208) isolates belonged to Type 1 and 3 (Chitose) respectively. When, the previously reported MPSP type 7 is also considered from the same study area, Theileria orientalis types 1, 3 and 7 are observed in south India. SSU rRNA sequence of South Indian T. annulata (JX294461) showed a maximum identity with Asian isolates while the Tams1 merozoite surface antigen (MSA) gene (JX648210) showed maximum identity with north Indian isolate.

In vitro evaluation of acaricidal activity of fipronil against Haemaphysalis bispinosa based on adult immersion test.

Fipronil is a phenylpyrazole family insecticide which mainly affects the nervous system of insects. In the present study, the in vitro acaricidal effects of the compound against the widely prevalent multihost tick, Haemaphysalis bispinosa was assessed. The lowest concentration at which complete adult tick mortality was observed was at 25 ppm while complete absence of egg mass observed at 10 ppm. Hundred per cent inhibition of fecundity was observed at 1 ppm while complete blocking of hatching of the laid ova was observed even at 500 ppb.

Intubating condition, hemodynamic parameters and upper airway morbidity: A comparison of intubating laryngeal mask airway with standard direct laryngoscopy.

BACKGROUND: Intubating Laryngeal Mask Airway (ILMA) is a relatively new device designed to have better intubating characteristics than the standard Laryngeal Mask Airway. This study was designed to compare Intubating Laryngeal Mask with standard Direct Laryngoscopy (DLS), taking into account ease of intubation, time taken for intubation, success rate of intubation, hemodynamic responses and upper airway morbidity. MATERIALS AND METHODS: Sixty patients, ASA I or II, of age between 20 and 60 years, were enrolled in this prospective and randomized study. They were randomly allocated to one of the two groups: group ILMA, Intubating Laryngeal Mask Airway; group DLS, Direct Laryngoscopy. The patients were intubated orally using either equipment after induction of general anesthesia. RESULTS AND CONCLUSIONS: DLS is comparatively a faster method to secure tracheal intubation than Intubating Laryngeal Mask. ILMA offers no advantage in attenuating the hemodynamic responses compared to direct laryngoscope. The success rate of intubation through Intubating Laryngeal Mask is comparable with that of DLS. The upper airway morbidity and mean oxygen saturation are comparable in both the groups.

Effects of solvents and surfactants against Haemaphysalis bispinosa.

As per the report published by FAO (2004), the tick population in India has developed resistance against all the available acaricides. Hence, newer methods of control including potential herbal agents are required to reduce the problems caused by the ticks. Most of the herbal extracts or their fractions are dissolved in polar or non-polar solvents or detergents before tested for acaricidal activity and these diluents should be of little acaricidal activity. In the present study, adult immersion test (AIT) was carried out on adult engorged female Haemaphysalis bispinosa ticks to detect the acaricidal activity of different solvents viz., nbutanol, glycerol, acetone, ethanol, methanol and surfactants (at 1 per cent dilution) like dimethyl sulphoxide (DMSO), tween 20 and triton X- 100. The study revealed that methanol was the least toxic solvent while tween 20 (1 per cent) was the least toxic detergent against H. bispinosa.