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Srikanta Ghosh - One of the best experts on this subject based on the ideXlab platform.

  • Molecular, histological and ultrastructural characterization of cytotoxic effects of amitraz on the ovaries of engorged females of Rhipicephalus (Boophilus) Annulatus
    Experimental parasitology, 2019
    Co-Authors: Sreelekha Kanapadinchareveetil, Suresh Narayanan Nair, Reghu Ravindran, Sanis Juliet, Leena Chandrasekhar, Anu Pious, Harikumar S. Kartha, Karapparambu Gopalan Ajithkumar, Srikanta Ghosh
    Abstract:

    Abstract In the present study, the cytotoxic effects of amitraz, an octopamine receptor agonist on the reproductive system of engorged adult females of Rhipicephalus (Boophilus) Annulatus were assessed using histology, electron microscopy and octopamine beta (OCTβ) receptor transcriptional expression analysis. Adult immersion test (AIT) was performed by immersing the fully engorged female ticks for 2 min in different concentrations of amitraz (200, 250, 300, 350 ppm). Amitraz at the dose of 300 ppm, caused an adult tick mortality of 16.66 ± 6.80 per cent, inhibition of fecundity of 75.80 per cent and hatching of 50 per cent of ova laid by treated ticks. Histological changes in the ovaries of ticks collected after 24 h of treatment with amitraz (300 ppm), in comparison with controls (distilled water/methanol) were identified by microscopical examination of sections (4  μm) stained using haematoxylin and eosin. These changes included reduction in size and basophilia of stage I oocytes, presence of cytoplasmic vacuoles of various sizes around germinal vesicle of stage II oocytes, wavy basement membrane of stage III oocytes and reduction in size and number of mature stage IV and V oocytes. Electron microscopy was employed for understanding the structural changes in the ultrathin sections (60 nm) of ovaries. Ticks treated with amitraz showed major ultrastructural changes such as irregular nuclear membrane, crystolysis of mitochondria and detachment of external and internal layers of basal lamina of oocytes. The cDNA synthesized from the total RNA of whole ticks and ovaries of ticks treated with amitraz along with controls were used for relative quantification of Octopamine β receptor (OCTβ-R) expression based on the 2−ΔΔCT method by quantitative real time PCR (qRT PCR). Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as endogenous control. Down regulation of expression of OCTβ-R mRNA in the ovaries of amitraz treated ticks was observed compared to controls. Thus, the inhibition of fecundity observed in the ticks treated with amitraz can be attributed to the major structural changes and decreased expression of OCT β receptor mRNA induced by it in the ovary.

  • Ixodid Tick Vectors of Wild Mammals and Reptiles of Southern India.
    Journal of arthropod-borne diseases, 2018
    Co-Authors: K G Ajith Kumar, Reghu Ravindran, Leena Chandrasekhar, Joju Johns, George Chandy, Kavitha Rajagopal, Ajith Jacob George, Srikanta Ghosh
    Abstract:

    Background: We aimed to focus on the ixodid ticks parasitizing wild mammals and reptiles from Wayanad Wildlife Sanctuary, Western Ghat, southern India. Methods: The taxonomic identification of ticks collected from wild mammals and reptiles was performed based on the morphology of adults. Results: We revealed eight species of ticks including, Amblyomma integrum , Rhipicephalus ( Boophilus ) Annulatus , Haemaphysalis ( Kaiseriana ) spinigera , H. ( K. ) shimoga , H. ( K. ) bispinosa , H. ( Rhipistoma ) i ndica , Rhipicephalus haemaphysaloides and R. sanguineus s.l. collected from nine species of wild mammals while four tick species Ablyomma kraneveldi , A. pattoni , A. gervaisi and A. javanense parasitizing on four species of reptiles. The highest host rich­ness was shown by H. ( K. ) bispinosa and R. haemaphysaloides parasitizing six and five different host species, re­spectively.  Reports of R. ( B. ) Annulatus on sambar deer, A. javanense and A. kraneveldi on python as well as A. pat­toni on Indian rat snake are the new host records from this region. Conclusion: Eight species of ticks parasitizing on nine species of wild mammals and four species of parasitizing on four species of reptiles were identified. The highest host richness was shown by H. ( K .) bispinosa and R. haemaphy­saloides . H. spinigera as the vector of KFD was also identified in this study.

  • Ultrastructural analysis of oocytes of Rhipicephalus (Boophilus) Annulatus during postengorgement period as a tool to evaluate the cytotoxic effects of amitraz and deltamethrin on the germinative cells.
    Veterinary parasitology, 2017
    Co-Authors: Kanapadinchareveetil Sreelekha, Suresh Narayanan Nair, Reghu Ravindran, Sanis Juliet, Leena Chandrasekhar, K. G. Ajithkumar, Harikumar S. Kartha, Srikanta Ghosh
    Abstract:

    Abstract The present study utilizes the ultrastructural analysis of the fully engorged female Rhipicephalus (Boophilus) Annulatus ticks, as a tool to evaluate the cytotoxic potential of deltamethrin and amitraz on the germinative cells. The ultrastructural analysis of the ovary of the normal (untreated) R (B.) Annulatus revealed, oocytes in different stages of development, attached to the ovary wall by pedicel cells. The attachment site of oocyte to the pedicel cell was characterized by indentations of the plasma membrane. The oocyte was bound by three cell membranes viz., plasma membrane, chorion and basal lamina. The stages of oocytes were differentiated ultrastructurally based on the features of their outer membrane and the number and size of lipid and yolk droplets. Detailed day wise analysis of ultrastructural changes in the ovary during the post-engorgement period revealed the occurrence of the degenerative changes from day five onwards. These appeared first in the oocytes followed by the germinal epithelium. The ovary of ticks treated with methanol (control), revealed similar topographies as that of a normal ovary except for the presence of very few oocytes with ring shaped nucleoli. Ultrastructurally, treatment with deltamethrin produced more prominent and extensive morphological alterations when compared to amitraz. In the case of ticks treated with amitraz, the oocytes of stage IV and V showed wavy and disrupted outer boundaries along with the loss of integrity of the yolk droplets. Uneven nuclear membranes of stage II oocytes and cristolysis of mitochondria of mature oocytes were the other changes noticed. Ticks treated with deltamethrin revealed prominent modifications such as, detachment of the basal lamina, wrinkled boundary, inconsistent nuclear membrane, ring shaped nucleoli and chromatin clumping in the case of the early stage oocytes (I and II), whereas swelling and cristolysis of mitochondria were seen in mature oocytes. The study further indicated that, in addition to the previous proven neurotoxic effects, these compounds act directly on the ovary of tick.

  • Research Article Acaricidal Activity of Petroleum Ether Extract of Leaves of Tetrastigma leucostaphylum (Dennst.) Alston
    2016
    Co-Authors: K Ajith G Kumar, Srikanta Ghosh
    Abstract:

    License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The acaricidal activity of the petroleum ether extract of leaves of Tetrastigma leucostaphylum (Dennst.) Alston (family: Vitaceae) against Rhipicephalus (Boophilus) Annulatus was assessed using adult immersion test (AIT). The per cent of adult mortality, inhibition of fecundity, and blocking of hatching of eggs were studied at different concentrations. The extract at 10 % concentration showed 88.96 % inhibition of fecundity, 58.32 % of adult tick mortality, and 50 % inhibition of hatching. Peak mortality rate was observed after day 5 of treatment. Mortality of engorged female ticks, inhibition of fecundity, and hatching of eggs were concentration dependent.The LC 50 value of the extract againstR. (B.) Annulatuswas 10.46%.TheHPTLC profiling of the petroleum ether extract revealed the presence of at least seven polyvalent components. In the petroleum ether extract, nicotine was identified as one of the components up to a concentration of 5.4%. However, nicotine did not reveal any acaricidal activity up to 20000 pp

  • Histoarchitecture of the ovary of Rhipicephalus (Boophilus) Annulatus during pre- and postengorgement period.
    TheScientificWorldJournal, 2015
    Co-Authors: Sreelekha Kanapadinchareveetil, Suresh Narayanan Nair, Reghu Ravindran, Sanis Juliet, Leena Chandrasekhar, Dibya Ranjan Lenka, Jyothimol Gopi, Aswathi Vasu, Ajith Kumar Kgopalan, Srikanta Ghosh
    Abstract:

    The present communication describes the detailed day wise study of histological changes of the ovary of Rhipicephalus (Boophilus) Annulatus in the postengorgement period together with the systematic classification of their oocytes. The ovary of R. (B.) Annulatus is panoistic type with an asynchronous development of oocytes. All the stages (II, III, IV, and V) of oocytes except stage I were similar to R. (B.) microplus. The stage I oocytes showed basophilia, which was not reported earlier in other species of ticks. Day wise changes were in the form of presence of oogonia in partially fed and day one engorged adults, considerable degeneration of oocytes on day two, emergence of new wave of oocytes on day three, presence of mature oocytes up to day eight, and complete degeneration of ovarian tissue from day eight onwards. The degenerative changes in the ovary appeared initially in the oocytes followed by germinal epithelium.

Adalberto A. Pérez De León - One of the best experts on this subject based on the ideXlab platform.

  • EFFICACY OF WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS) TREATMENT FOR CATTLE FEVER TICKS IN SOUTHERN TEXAS, USA.
    Journal of wildlife diseases, 2020
    Co-Authors: Chase R. Currie, David G. Hewitt, J. Alfonso Ortega-s., Greta Schuster, Tyler A. Campbell, Kim Lohmeyer, David B. Wester, Adalberto A. Pérez De León
    Abstract:

    Abstract White-tailed deer (Odocoileus virginianus) serve as a host for cattle fever ticks (Rhipicephalus [Boophilus] microplus and Rhipicephalus [Boophilus] Annulatus; CFTs); therefore, deer are a...

  • Rhipicephalus (Boophilus) microplus (Ixodida: Ixodidae) Larvae Collected From Vegetation in the Coastal Wildlife Corridor of Southern Texas and Research Solutions for Integrated Eradication.
    Journal of medical entomology, 2020
    Co-Authors: Weste L. A. Osbrink, Allan T. Showler, Veronica Abrigo, Adalberto A. Pérez De León
    Abstract:

    The potential for reinvasion of the United States by cattle fever ticks, Rhipicephalus (Boophilus) Annulatus and Rhipicephalus microplus (Canestrini), which remain established in Mexico, threatens the viability of the domestic livestock industry because these ticks vector the causal agents (Babesia bovis and Babesia bigemina) of bovine babesiosis. The Cattle Fever Tick Eradication Program safeguards the health of the national cattle herd preventing the reemergence of bovine babesiosis by keeping the United States free of cattle fever ticks. Here, the collection of free-living southern cattle tick, R. microplus, larvae by sweeping flannel flags over vegetation in the wildlife corridor of Cameron and Willacy Counties, TX, is reported. Finding R. microplus larvae on vegetation complements reports of infestations in wildlife hosts inhabiting the southern Texas coastal plains. Land uses and environmental conditions have changed since cattle fever ticks were eradicated from the United States by 1943. These changes complicate efforts by the Cattle Fever Tick Eradication Program to keep cattle in the United States free of the cattle fever tick disease vectors. Current scientific research on technologies that could be used for area-wide management of fever tick larvae in south Texas and how this could be applied to integrated eradication efforts are discussed.

  • Integrated Strategy for Sustainable Cattle Fever Tick Eradication in USA is Required to Mitigate the Impact of Global Change
    Frontiers in physiology, 2012
    Co-Authors: Adalberto A. Pérez De León, Matthew T. Messenger, Greta Schuster, Pete D. Teel, Allan N. D. Auclair, Felix D. Guerrero, Robert J. Miller
    Abstract:

    The ticks Rhipicephalus (Boophilus) Annulatus and R. (B.) microplus, commonly known as cattle and southern cattle tick, respectively, impede the development and sustainability of livestock industries throughout tropical and other world regions. They affect animal productivity and wellbeing directly through their obligate blood feeding habit and indirectly by serving as vectors of the infectious agents causing bovine babesiosis and anaplasmosis. The monumental scientific discovery of certain arthropod species as vectors of infectious agents is associated with the history of research on bovine babesiosis and R. Annulatus. Together, R. microplus and R. Annulatus are referred to as cattle fever ticks (CFT). Bovine babesiosis became a regulated foreign animal disease in the United States of America (U.S.) through efforts of the Cattle Fever Tick Eradication Program (CFTEP) established in 1906. The U.S. was declared free of CFT in 1943, with the exception of a permanent quarantine zone in south Texas along the border with Mexico. This achievement contributed greatly to the development and productivity of animal agriculture in the U.S. The permanent quarantine zone buffers CFT incursions from Mexico where both ticks and babesiosis are endemic. Until recently, the elimination of CFT outbreaks relied solely on the use of coumaphos, an organophosphate acaricide, in dipping vats or as a spray to treat livestock, or the vacation of pastures. However, ecological, societal, and economical changes are shifting the paradigm of systematically treating livestock to eradicate CFT. Keeping the U.S. CFT-free is a critical animal health issue affecting the economic stability of livestock and wildlife enterprises. Here, we describe vulnerabilities associated with global change forces challenging the CFTEP. The concept of integrated CFT eradication is discussed in reference to global change.

  • Exploring the use of an anti-tick vaccine as a tool for the integrated eradication of the cattle fever tick, Rhipicephalus (Boophilus) Annulatus.
    Vaccine, 2012
    Co-Authors: Robert J. Miller, Agustín Estrada-peña, Consuelo Almazán, Andrew G. Allen, Lauren Jory, Kathleen M. Yeater, Matthew T. Messenger, Dee Ellis, Adalberto A. Pérez De León
    Abstract:

    Bovine babesiosis, also known as cattle fever, is a tick-borne protozoal disease foreign to the United States. It was eradicated by eliminating the vector species, Rhipicephalus (Boophilus) Annulatus and Rhipicephalus (Boophilus) microplus, through the efforts of the Cattle Fever Tick Eradication Program (CFTEP), with the exception of a permanent quarantine zone (PQZ) in south Texas along the border with Mexico. Keeping the U.S. free of cattle fever ticks in a sustainable manner is a critical national agricultural biosecurity issue. The efficacy of a Bm86-based anti-tick vaccine commercialized outside of the U.S. was evaluated against a strain of R. Annulatus originated from an outbreak in Texas. Vaccination controlled 99.9 and 91.4% of the ticks 8 weeks and 5.5 months after the initial vaccination, respectively. Computer modeling of habitat suitability within the PQZ typically at risk of re-infestation with R. Annulatus from Mexico predicted that at a level of control greater than 40%, eradication would be maintained indefinitely. Efficacy and computer modeling data indicate that the integration of vaccination using a Bm86-based anti-tick vaccine with standard eradication practices within the northwestern half of the PQZ could incentivize producers to maintain cattle on pasture thereby avoiding the need to vacate infested premises. Implementing this epidemiologically proactive strategy offers the opportunity to prevent R. Annulatus outbreaks in the U.S., which would represent a significant shift in the way the CFTEP operates.

Reghu Ravindran - One of the best experts on this subject based on the ideXlab platform.

  • Acaricidal Activity of Artemisia nilagirica Leaves Against Rhipicephalus (Boophilus) Annulatus Ticks.
    Planta medica, 2020
    Co-Authors: Darsana Udayan, Kanapadinchareveetil Sreelekha, Suresh Narayanan Nair, Reghu Ravindran, Sanis Juliet, K. G. Ajithkumar, Sunil Athalathil, Thumadath Palayullaparambil Adarshkrishna, Leena Chandrashekar, Srikant Ghosh
    Abstract:

    Since time immemorial, human beings have used various parts of plants in either prevention or treatment of ailments. Plants are rich sources of secondary metabolites such as alkaloids, steroids, terpenoids, flavonoids, and phenolic compounds with a high structural diversity. Many plants/herbs with specific biological activities such as antitumor, antioxidant, anti-inflammatory, antifungal, sedative, and acaricidal activity have been reported. Artemisia nilagirica (C. B. Clarke) Pamp. (Compositae) is a plant traditionally used for insect control in the southern part of India. Previous studies have demonstrated the activity of Artemisia species against pests. The present study thus evaluates the acaricidal activity of crude ethanolic extract of A. nilagirica leaves and its fractions against Rhipicephalus (Boophilus) Annulatus. Ticks are ectoparasites that transmit several protozoal, viral, and rickettsial diseases. In south India, R. (B.) Annulatus is the commonly observed tick species. Control of these acarine parasites that adversely affect milk and meat production is a tough task. Chemical acaricides such as organophosphates, synthetic pyrethroids, amitraz, and ivermectin are commonly used in tick control. The high cost, environmental hazards, and development of acaricidal resistance are some of the drawbacks of these chemical acaricides. Plant-based formulations are one of the promising approaches for the control of ectoparasites. Previously, extracts from various medicinal/aromatic plants were reported for acaricidal activity from our laboratory, such as Tetrastigma leucostaphylum (Dennst.) Alston, Chassalia curviflora (Wall.) Thwaites, Jatropha curcas L., and Ageratum conyzoides Hieron. Biochemical quantification, fluorescence analysis, and primary phytochemical analysis are already reported for the ethanolic extract and its fractions of areal parts of A. nilagirica. Phytochemical characterization of ethanolic extract of A. nilagirica from Kerala, India was shown to have the presence of terpenoids, flavonoids, steroids, saponins, fixed oils and fats, tannins, and glycosides.

  • Molecular, histological and ultrastructural characterization of cytotoxic effects of amitraz on the ovaries of engorged females of Rhipicephalus (Boophilus) Annulatus
    Experimental parasitology, 2019
    Co-Authors: Sreelekha Kanapadinchareveetil, Suresh Narayanan Nair, Reghu Ravindran, Sanis Juliet, Leena Chandrasekhar, Anu Pious, Harikumar S. Kartha, Karapparambu Gopalan Ajithkumar, Srikanta Ghosh
    Abstract:

    Abstract In the present study, the cytotoxic effects of amitraz, an octopamine receptor agonist on the reproductive system of engorged adult females of Rhipicephalus (Boophilus) Annulatus were assessed using histology, electron microscopy and octopamine beta (OCTβ) receptor transcriptional expression analysis. Adult immersion test (AIT) was performed by immersing the fully engorged female ticks for 2 min in different concentrations of amitraz (200, 250, 300, 350 ppm). Amitraz at the dose of 300 ppm, caused an adult tick mortality of 16.66 ± 6.80 per cent, inhibition of fecundity of 75.80 per cent and hatching of 50 per cent of ova laid by treated ticks. Histological changes in the ovaries of ticks collected after 24 h of treatment with amitraz (300 ppm), in comparison with controls (distilled water/methanol) were identified by microscopical examination of sections (4  μm) stained using haematoxylin and eosin. These changes included reduction in size and basophilia of stage I oocytes, presence of cytoplasmic vacuoles of various sizes around germinal vesicle of stage II oocytes, wavy basement membrane of stage III oocytes and reduction in size and number of mature stage IV and V oocytes. Electron microscopy was employed for understanding the structural changes in the ultrathin sections (60 nm) of ovaries. Ticks treated with amitraz showed major ultrastructural changes such as irregular nuclear membrane, crystolysis of mitochondria and detachment of external and internal layers of basal lamina of oocytes. The cDNA synthesized from the total RNA of whole ticks and ovaries of ticks treated with amitraz along with controls were used for relative quantification of Octopamine β receptor (OCTβ-R) expression based on the 2−ΔΔCT method by quantitative real time PCR (qRT PCR). Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as endogenous control. Down regulation of expression of OCTβ-R mRNA in the ovaries of amitraz treated ticks was observed compared to controls. Thus, the inhibition of fecundity observed in the ticks treated with amitraz can be attributed to the major structural changes and decreased expression of OCT β receptor mRNA induced by it in the ovary.

  • Ixodid Tick Vectors of Wild Mammals and Reptiles of Southern India.
    Journal of arthropod-borne diseases, 2018
    Co-Authors: K G Ajith Kumar, Reghu Ravindran, Leena Chandrasekhar, Joju Johns, George Chandy, Kavitha Rajagopal, Ajith Jacob George, Srikanta Ghosh
    Abstract:

    Background: We aimed to focus on the ixodid ticks parasitizing wild mammals and reptiles from Wayanad Wildlife Sanctuary, Western Ghat, southern India. Methods: The taxonomic identification of ticks collected from wild mammals and reptiles was performed based on the morphology of adults. Results: We revealed eight species of ticks including, Amblyomma integrum , Rhipicephalus ( Boophilus ) Annulatus , Haemaphysalis ( Kaiseriana ) spinigera , H. ( K. ) shimoga , H. ( K. ) bispinosa , H. ( Rhipistoma ) i ndica , Rhipicephalus haemaphysaloides and R. sanguineus s.l. collected from nine species of wild mammals while four tick species Ablyomma kraneveldi , A. pattoni , A. gervaisi and A. javanense parasitizing on four species of reptiles. The highest host rich­ness was shown by H. ( K. ) bispinosa and R. haemaphysaloides parasitizing six and five different host species, re­spectively.  Reports of R. ( B. ) Annulatus on sambar deer, A. javanense and A. kraneveldi on python as well as A. pat­toni on Indian rat snake are the new host records from this region. Conclusion: Eight species of ticks parasitizing on nine species of wild mammals and four species of parasitizing on four species of reptiles were identified. The highest host richness was shown by H. ( K .) bispinosa and R. haemaphy­saloides . H. spinigera as the vector of KFD was also identified in this study.

  • In vitro efficacy of amitraz, coumaphos, deltamethrin and lindane against engorged female Rhipicephalus (Boophilus) Annulatus and Haemaphysalis bispinosa ticks.
    Experimental and Applied Acarology, 2018
    Co-Authors: Reghu Ravindran, Kanapadinchareveetil Sreelekha, G. Jyothimol, K. K. Amithamol, A. R. Sunil, Leena Chandrasekhar, Dibya Ranjan Lenka, Achuthkumar Amritha, Nanjundappa Sathish, Darsana Udayan
    Abstract:

    The present study compares the in vitro efficacy of four chemical acaricides, viz. amitraz, coumaphos, deltamethrin and lindane, against Rhipicephalus (Boophilus) Annulatus and Haemaphysalis bispinosa ticks based on adult immersion tests. Amitraz, at 350 ppm, elicited 29.2 ± 4.17% mortality against R. (B.) Annulatus, 100% inhibition of fecundity and absence of hatching of eggs laid by treated ticks. The same compound at 300 ppm caused 62.5 ± 12.5% mortality against H. bispinosa, 96.7% inhibition of fecundity and complete blocking of eclosion. The LC50 value of amitraz against susceptible H. bispinosa was 181 ppm. Deltamethrin at 400 ppm, elicited 25.0 ± 4.81% adult R. (B.) Annulatus mortality, 97.5% inhibition of fecundity and absence of egg hatching. Complete blocking of egg hatching was observed even at 30 ppm. However, deltamethrin (at 50 ppm) elicited 75.0 ± 10.76% mortality against H. bispinosa, 65.8% inhibition of fecundity and very low egg hatching (10%). The LC50 for deltamethrin against susceptible H. bispinosa was 33.8 ppm. Coumaphos at 50 ppm, caused mortality of 70.8 ± 4.17% with R. (B.) Annulatus whereas 100% mortality was observed against H. bispinosa. The LC50 values of coumaphos against R. (B.) Annulatus and H. bispinosa were 9 and 8.75 ppm, respectively. Complete inhibition (100%) of fecundity was observed even at 30 ppm against both parasites. Complete blocking of egg hatching was also observed even at 10 ppm of coumaphos. Lindane at 1000 ppm caused mortality of 87.5 ± 7.98% against R. (B.) Annulatus and 83.3% mortality against H. bispinosa at 100 ppm. The LC50 values of lindane against R. (B.) Annulatus and H. bispinosa were 157 and 8.61 ppm, respectively. Complete inhibition of fecundity was observed with R. (B.) Annulatus treated with lindane above 200 ppm and with H. bispinosa at a concentration above 50 ppm. Complete blocking of egg hatching was observed in R. (B.) Annulatus, even at 100 ppm. Lindane caused 100% blocking of egg hatching at 1 ppm in the case of H. bispinosa.

  • Ultrastructural analysis of oocytes of Rhipicephalus (Boophilus) Annulatus during postengorgement period as a tool to evaluate the cytotoxic effects of amitraz and deltamethrin on the germinative cells.
    Veterinary parasitology, 2017
    Co-Authors: Kanapadinchareveetil Sreelekha, Suresh Narayanan Nair, Reghu Ravindran, Sanis Juliet, Leena Chandrasekhar, K. G. Ajithkumar, Harikumar S. Kartha, Srikanta Ghosh
    Abstract:

    Abstract The present study utilizes the ultrastructural analysis of the fully engorged female Rhipicephalus (Boophilus) Annulatus ticks, as a tool to evaluate the cytotoxic potential of deltamethrin and amitraz on the germinative cells. The ultrastructural analysis of the ovary of the normal (untreated) R (B.) Annulatus revealed, oocytes in different stages of development, attached to the ovary wall by pedicel cells. The attachment site of oocyte to the pedicel cell was characterized by indentations of the plasma membrane. The oocyte was bound by three cell membranes viz., plasma membrane, chorion and basal lamina. The stages of oocytes were differentiated ultrastructurally based on the features of their outer membrane and the number and size of lipid and yolk droplets. Detailed day wise analysis of ultrastructural changes in the ovary during the post-engorgement period revealed the occurrence of the degenerative changes from day five onwards. These appeared first in the oocytes followed by the germinal epithelium. The ovary of ticks treated with methanol (control), revealed similar topographies as that of a normal ovary except for the presence of very few oocytes with ring shaped nucleoli. Ultrastructurally, treatment with deltamethrin produced more prominent and extensive morphological alterations when compared to amitraz. In the case of ticks treated with amitraz, the oocytes of stage IV and V showed wavy and disrupted outer boundaries along with the loss of integrity of the yolk droplets. Uneven nuclear membranes of stage II oocytes and cristolysis of mitochondria of mature oocytes were the other changes noticed. Ticks treated with deltamethrin revealed prominent modifications such as, detachment of the basal lamina, wrinkled boundary, inconsistent nuclear membrane, ring shaped nucleoli and chromatin clumping in the case of the early stage oocytes (I and II), whereas swelling and cristolysis of mitochondria were seen in mature oocytes. The study further indicated that, in addition to the previous proven neurotoxic effects, these compounds act directly on the ovary of tick.

Sanis Juliet - One of the best experts on this subject based on the ideXlab platform.

  • Acaricidal Activity of Artemisia nilagirica Leaves Against Rhipicephalus (Boophilus) Annulatus Ticks.
    Planta medica, 2020
    Co-Authors: Darsana Udayan, Kanapadinchareveetil Sreelekha, Suresh Narayanan Nair, Reghu Ravindran, Sanis Juliet, K. G. Ajithkumar, Sunil Athalathil, Thumadath Palayullaparambil Adarshkrishna, Leena Chandrashekar, Srikant Ghosh
    Abstract:

    Since time immemorial, human beings have used various parts of plants in either prevention or treatment of ailments. Plants are rich sources of secondary metabolites such as alkaloids, steroids, terpenoids, flavonoids, and phenolic compounds with a high structural diversity. Many plants/herbs with specific biological activities such as antitumor, antioxidant, anti-inflammatory, antifungal, sedative, and acaricidal activity have been reported. Artemisia nilagirica (C. B. Clarke) Pamp. (Compositae) is a plant traditionally used for insect control in the southern part of India. Previous studies have demonstrated the activity of Artemisia species against pests. The present study thus evaluates the acaricidal activity of crude ethanolic extract of A. nilagirica leaves and its fractions against Rhipicephalus (Boophilus) Annulatus. Ticks are ectoparasites that transmit several protozoal, viral, and rickettsial diseases. In south India, R. (B.) Annulatus is the commonly observed tick species. Control of these acarine parasites that adversely affect milk and meat production is a tough task. Chemical acaricides such as organophosphates, synthetic pyrethroids, amitraz, and ivermectin are commonly used in tick control. The high cost, environmental hazards, and development of acaricidal resistance are some of the drawbacks of these chemical acaricides. Plant-based formulations are one of the promising approaches for the control of ectoparasites. Previously, extracts from various medicinal/aromatic plants were reported for acaricidal activity from our laboratory, such as Tetrastigma leucostaphylum (Dennst.) Alston, Chassalia curviflora (Wall.) Thwaites, Jatropha curcas L., and Ageratum conyzoides Hieron. Biochemical quantification, fluorescence analysis, and primary phytochemical analysis are already reported for the ethanolic extract and its fractions of areal parts of A. nilagirica. Phytochemical characterization of ethanolic extract of A. nilagirica from Kerala, India was shown to have the presence of terpenoids, flavonoids, steroids, saponins, fixed oils and fats, tannins, and glycosides.

  • Molecular, histological and ultrastructural characterization of cytotoxic effects of amitraz on the ovaries of engorged females of Rhipicephalus (Boophilus) Annulatus
    Experimental parasitology, 2019
    Co-Authors: Sreelekha Kanapadinchareveetil, Suresh Narayanan Nair, Reghu Ravindran, Sanis Juliet, Leena Chandrasekhar, Anu Pious, Harikumar S. Kartha, Karapparambu Gopalan Ajithkumar, Srikanta Ghosh
    Abstract:

    Abstract In the present study, the cytotoxic effects of amitraz, an octopamine receptor agonist on the reproductive system of engorged adult females of Rhipicephalus (Boophilus) Annulatus were assessed using histology, electron microscopy and octopamine beta (OCTβ) receptor transcriptional expression analysis. Adult immersion test (AIT) was performed by immersing the fully engorged female ticks for 2 min in different concentrations of amitraz (200, 250, 300, 350 ppm). Amitraz at the dose of 300 ppm, caused an adult tick mortality of 16.66 ± 6.80 per cent, inhibition of fecundity of 75.80 per cent and hatching of 50 per cent of ova laid by treated ticks. Histological changes in the ovaries of ticks collected after 24 h of treatment with amitraz (300 ppm), in comparison with controls (distilled water/methanol) were identified by microscopical examination of sections (4  μm) stained using haematoxylin and eosin. These changes included reduction in size and basophilia of stage I oocytes, presence of cytoplasmic vacuoles of various sizes around germinal vesicle of stage II oocytes, wavy basement membrane of stage III oocytes and reduction in size and number of mature stage IV and V oocytes. Electron microscopy was employed for understanding the structural changes in the ultrathin sections (60 nm) of ovaries. Ticks treated with amitraz showed major ultrastructural changes such as irregular nuclear membrane, crystolysis of mitochondria and detachment of external and internal layers of basal lamina of oocytes. The cDNA synthesized from the total RNA of whole ticks and ovaries of ticks treated with amitraz along with controls were used for relative quantification of Octopamine β receptor (OCTβ-R) expression based on the 2−ΔΔCT method by quantitative real time PCR (qRT PCR). Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as endogenous control. Down regulation of expression of OCTβ-R mRNA in the ovaries of amitraz treated ticks was observed compared to controls. Thus, the inhibition of fecundity observed in the ticks treated with amitraz can be attributed to the major structural changes and decreased expression of OCT β receptor mRNA induced by it in the ovary.

  • Ultrastructural analysis of oocytes of Rhipicephalus (Boophilus) Annulatus during postengorgement period as a tool to evaluate the cytotoxic effects of amitraz and deltamethrin on the germinative cells.
    Veterinary parasitology, 2017
    Co-Authors: Kanapadinchareveetil Sreelekha, Suresh Narayanan Nair, Reghu Ravindran, Sanis Juliet, Leena Chandrasekhar, K. G. Ajithkumar, Harikumar S. Kartha, Srikanta Ghosh
    Abstract:

    Abstract The present study utilizes the ultrastructural analysis of the fully engorged female Rhipicephalus (Boophilus) Annulatus ticks, as a tool to evaluate the cytotoxic potential of deltamethrin and amitraz on the germinative cells. The ultrastructural analysis of the ovary of the normal (untreated) R (B.) Annulatus revealed, oocytes in different stages of development, attached to the ovary wall by pedicel cells. The attachment site of oocyte to the pedicel cell was characterized by indentations of the plasma membrane. The oocyte was bound by three cell membranes viz., plasma membrane, chorion and basal lamina. The stages of oocytes were differentiated ultrastructurally based on the features of their outer membrane and the number and size of lipid and yolk droplets. Detailed day wise analysis of ultrastructural changes in the ovary during the post-engorgement period revealed the occurrence of the degenerative changes from day five onwards. These appeared first in the oocytes followed by the germinal epithelium. The ovary of ticks treated with methanol (control), revealed similar topographies as that of a normal ovary except for the presence of very few oocytes with ring shaped nucleoli. Ultrastructurally, treatment with deltamethrin produced more prominent and extensive morphological alterations when compared to amitraz. In the case of ticks treated with amitraz, the oocytes of stage IV and V showed wavy and disrupted outer boundaries along with the loss of integrity of the yolk droplets. Uneven nuclear membranes of stage II oocytes and cristolysis of mitochondria of mature oocytes were the other changes noticed. Ticks treated with deltamethrin revealed prominent modifications such as, detachment of the basal lamina, wrinkled boundary, inconsistent nuclear membrane, ring shaped nucleoli and chromatin clumping in the case of the early stage oocytes (I and II), whereas swelling and cristolysis of mitochondria were seen in mature oocytes. The study further indicated that, in addition to the previous proven neurotoxic effects, these compounds act directly on the ovary of tick.

  • Histoarchitecture of the ovary of Rhipicephalus (Boophilus) Annulatus during pre- and postengorgement period.
    TheScientificWorldJournal, 2015
    Co-Authors: Sreelekha Kanapadinchareveetil, Suresh Narayanan Nair, Reghu Ravindran, Sanis Juliet, Leena Chandrasekhar, Dibya Ranjan Lenka, Jyothimol Gopi, Aswathi Vasu, Ajith Kumar Kgopalan, Srikanta Ghosh
    Abstract:

    The present communication describes the detailed day wise study of histological changes of the ovary of Rhipicephalus (Boophilus) Annulatus in the postengorgement period together with the systematic classification of their oocytes. The ovary of R. (B.) Annulatus is panoistic type with an asynchronous development of oocytes. All the stages (II, III, IV, and V) of oocytes except stage I were similar to R. (B.) microplus. The stage I oocytes showed basophilia, which was not reported earlier in other species of ticks. Day wise changes were in the form of presence of oogonia in partially fed and day one engorged adults, considerable degeneration of oocytes on day two, emergence of new wave of oocytes on day three, presence of mature oocytes up to day eight, and complete degeneration of ovarian tissue from day eight onwards. The degenerative changes in the ovary appeared initially in the oocytes followed by germinal epithelium.

  • Contrasting effects of ethanolic extracts of leaf and flower of Chromolaena odorata against Rhipicephalus (Boophilus) Annulatus
    Indian Journal of Animal Sciences, 2015
    Co-Authors: Reghu Ravindran, Nayikottummal Devadas Chithra, Pattanur Edathil Deepa, Suresh Narayanan Nair, Sanis Juliet, Leena Chandrasekhar, Darsana Udayan, Karapparambu Gopalan Ajith Kumar, Sathish Nanjudappa, Srikanta Ghosh
    Abstract:

    In the present study, ethanolic extracts of leaves and flowers of Chromolaena odorata were compared at different dilutions (6.2 mg/mL, 12.5 mg/mL, 25 mg/mL, 50 mg/mL and 100 mg/mL) for their efficacy against ticks. Per cent adult mortality, inhibition of fecundity and hatching of laid ova were studied. Leaf extract did not cause any adult tick mortality. The negative values for the per cent inhibition of fecundity observed with the leaf extract indicated that it promoted egg laying. On the contrary, the ethanolic extract of flowers at 10% concentration caused 62% adult tick mortality and 80%inhibition of fecundity. However, both extracts did not produce any change in the hatching of the laid ova by treated ticks.

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  • Research on Integrated Management for Cattle Fever Ticks and Bovine Babesiosis in the United States and Mexico: Current Status and Opportunities for Binational Coordination.
    Pathogens (Basel Switzerland), 2020
    Co-Authors: Maria D. Esteve-gasent, Dee Ellis, Roger Iván Rodríguez-vivas, Raul F. Medina, Andy Schwartz, Baltazar Cortés Garcia, Carrie Hunt, Mackenzie Tietjen, Denise L Bonilla, Donald B. Thomas
    Abstract:

    Bovine babesiosis is a reportable transboundary animal disease caused by Babesia bovis and Babesiabigemina in the Americas where these apicomplexan protozoa are transmitted by the invasive cattle fever ticks Rhipicephalus (Boophilus) microplus and Rhipicephalus(Boophilus) Annulatus. In countries like Mexico where cattle fever ticks remain endemic, bovine babesiosis is detrimental to cattle health and results in a significant economic cost to the livestock industry. These cattle disease vectors continue to threaten the U.S. cattle industry despite their elimination through efforts of the Cattle Fever Tick Eradication Program. Mexico and the U.S. share a common interest in managing cattle fever ticks through their economically important binational cattle trade. Here, we report the outcomes of a meeting where stakeholders from Mexico and the U.S. representing the livestock and pharmaceutical industry, regulatory agencies, and research institutions gathered to discuss research and knowledge gaps requiring attention to advance progressive management strategies for bovine babesiosis and cattle fever ticks. Research recommendations and other actionable activities reflect commitment among meeting participants to seize opportunities for collaborative efforts. Addressing these research gaps is expected to yield scientific knowledge benefitting the interdependent livestock industries of Mexico and the U.S. through its translation into enhanced biosecurity against the economic and animal health impacts of bovine babesiosis and cattle fever ticks.

  • Survival of off-host unfed Rhipicephalus (Boophilus) Annulatus (Acari: Ixodidae) larvae in study arenas in relation to climatic factors and habitats in South Texas, USA.
    Ticks and tick-borne diseases, 2019
    Co-Authors: Emily Zamora, Donald B. Thomas, Brenda Leal, Robert K. Dearth
    Abstract:

    Abstract The cattle fever tick, Rhipicephalus Annulatus (Say), is an economically destructive arthropod because of its ability to vector bovine babesiosis. Cattle fever ticks can spend more than 90% of their life cycle as questing larvae, but the effect of climatic factors on their off-host behavior and survival is unclear. The goal of this study was to measure the effects of specific ecological factors on off-host larvae in nature. The study was conducted in a south Texas pasture over a 20-mo period, during which time larval populations were surveyed and ambient weather variables - relative humidity and temperatures – were recorded. Oviposition success and larval survival varied between cattle fever tick cohorts and was affected by relative humidity and canopied (with tree cover) versus exposed habitat. The results show that relative humidity and the interaction of relative humidity and inhabiting canopied habitats play a key role in oviposition success. Additionally, canopied habitats have a positive influence on off-host larval survival in the spring and summer.

  • efficacy of novaluron pyriproxyfen tekko pro insect growth regulators against amblyomma americanum acari ixodidae Rhipicephalus Boophilus Annulatus Rhipicephalus Boophilus microplus and Rhipicephalus sanguineus
    Journal of Medical Entomology, 2019
    Co-Authors: Allan T. Showler, William A. Donahue, Jessica L Harlien, Michael W. Donahue, Bret E. Vinson, Donald B. Thomas
    Abstract:

    Ixodids are globally distributed pests that transmit many disease agents. Increasing resistance to conventional acaricides raises the need for alternative tactics. Novaluron and pyriproxyfen are insect growth regulators (IGRs) that have variable potencies against acarines. We conducted in vitro and in vivo experiments to assess novaluron + pyriproxyfen (marketed as Tekko Pro) against four ixodid species. Laboratory assays on the brown dog tick, Rhipicephalus sanguineus (Latreille) (Ixodida: Ixodidae), and the lone star tick, Amblyomma americanum (L.) (Ixodida: Ixodidae), reduced metabolic activity in larvae and nymphs. Concentrations of novaluron + pyriproxyfen dried on filter paper impeded molting of larval R. sanguineus (less effective against nymphs). Molting A. americanum larvae were reduced by >95% using 4 and 8 µg/cm2 eliminated molting; nymphal molting was reduced but not halted even at 16 µg/cm2. On calves, novaluron + pyriproxyfen stopped larval A. americanum metabolic function 1 d post-treatment and larvae did not molt. When larvae were released 30 d after treatment, metabolic activity was reduced by 95% and molting was reduced by 94%. Southern cattle fever tick, Rhipicephalus (Boophilus) microplus (Canestrini) (Ixodida: Ixodidae), larvae released 1 d after treatment on calves were 99% prevented from reaching adulthood. The treatment did not interfere with larval development when larvae were released 52 d after treatment. The cattle fever tick, Rhipicephalus (Boophilus) Annulatus (Say) (Ixodida: Ixodidae), failed to reach adulthood when larvae were released on calves a day after treatment (residual activity was not assessed for R. Annulatus). These IGRs, and possibly others, offer an alternative to conventional acaricides for ixodid control on cattle.

  • Efficacy of Novaluron + Pyriproxyfen (Tekko Pro) Insect Growth Regulators Against Amblyomma americanum (Acari: Ixodidae), Rhipicephalus (Boophilus) Annulatus, Rhipicephalus (Boophilus) microplus, and Rhipicephalus sanguineus.
    Journal of medical entomology, 2019
    Co-Authors: Allan T. Showler, William A. Donahue, Jessica L Harlien, Michael W. Donahue, Bret E. Vinson, Donald B. Thomas
    Abstract:

    Ixodids are globally distributed pests that transmit many disease agents. Increasing resistance to conventional acaricides raises the need for alternative tactics. Novaluron and pyriproxyfen are insect growth regulators (IGRs) that have variable potencies against acarines. We conducted in vitro and in vivo experiments to assess novaluron + pyriproxyfen (marketed as Tekko Pro) against four ixodid species. Laboratory assays on the brown dog tick, Rhipicephalus sanguineus (Latreille) (Ixodida: Ixodidae), and the lone star tick, Amblyomma americanum (L.) (Ixodida: Ixodidae), reduced metabolic activity in larvae and nymphs. Concentrations of novaluron + pyriproxyfen dried on filter paper impeded molting of larval R. sanguineus (less effective against nymphs). Molting A. americanum larvae were reduced by >95% using 4 and 8 µg/cm2 eliminated molting; nymphal molting was reduced but not halted even at 16 µg/cm2. On calves, novaluron + pyriproxyfen stopped larval A. americanum metabolic function 1 d post-treatment and larvae did not molt. When larvae were released 30 d after treatment, metabolic activity was reduced by 95% and molting was reduced by 94%. Southern cattle fever tick, Rhipicephalus (Boophilus) microplus (Canestrini) (Ixodida: Ixodidae), larvae released 1 d after treatment on calves were 99% prevented from reaching adulthood. The treatment did not interfere with larval development when larvae were released 52 d after treatment. The cattle fever tick, Rhipicephalus (Boophilus) Annulatus (Say) (Ixodida: Ixodidae), failed to reach adulthood when larvae were released on calves a day after treatment (residual activity was not assessed for R. Annulatus). These IGRs, and possibly others, offer an alternative to conventional acaricides for ixodid control on cattle.