Problem of ticks and tick-borne diseases in India with special emphasis on progress in tick control research: A review

Ticks, as vectors of several zoonotic diseases, are ranked second only to mosquitoes as vectors. The diseases spread by ticks are a major constraint to animal productivity while causing morbidity and mortality in both animals and humans. A number of tick species have been recognised since long as vectors of lethal pathogens, viz. Crimean-Congo haemorrhagic fever virus (CCHFV), Kyasanur forest disease virus (KFDV), Babesia spp, Theileria, Rickettsia conorii, Anaplasma marginale, etc. and the damages caused by them are well-recognised. There is a need to reassess the renewed threat posed by the tick vectors and to prioritize the tick control research programme. This review is focused on the major tick-borne human and animal diseases in India and the progress in vector control research with emphasis on acaricide resistance, tick vaccine and the development of potential phytoacaricides as an integral part of integrated tick control programme

Co-immunization efficacy of recombinant antigens against Rhipicephalus microplus and Hyalomma anatolicum tick infestations

This article belongs to the Collection Advances in Tick Research.The immunoprophylactic management of ticks is the most effective option to control tick infestations and counter spread the acaricide resistance problem worldwide. Several researchers reported an inconsistent efficacy of the single antigen-based immunization of hosts against different tick species. In the present study, to develop a multi-target immunization protocol, proteins from Rhipicephalus microplus BM86 and Hyalomma anatolicum subolesin (SUB) and tropomyosin (TPM) were targeted to evaluate the cross-protective potential. The sequence identities of the BM86, SUB, and TPM coding genes amongst Indian tick isolates of targeted species were 95.6–99.8%, 98.7–99.6%, and 98.9–99.9%, respectively, while at the predicted amino acid level, the identities were 93.2 to 99.5, 97.6 to 99.4, and 98.2 to 99.3%. The targeted genes were expressed in the eukaryotic expression system, pKLAC2-Kluyveromyces lactis, and 100 µg each of purified recombinant protein (Bm86-89 kDa, SUB-21 kDa, and TPM-36 kDa) mixed with adjuvant was injected individually through the intramuscular route at different sites of the body on days 0, 30, and 60 to immunize cross-bred cattle. Post-immunization, a statistically significant (p < 0.001) antibody response (IgG, IgG1, and IgG2) in comparison to the control, starting from 15 to 140 days, against each antigen was recorded. Following multi-antigen immunization, the animals were challenged twice with the larvae of R. microplus and H. anatolicum and theadults of H. anatolicum, and a significant vaccine efficacy of 87.2% and 86.2% against H. anatolicum larvae and adults, respectively, and 86.7% against R. microplus was obtained. The current study provides significant support to develop a multi-antigen vaccine against cattle tick species.The authors are grateful to the Indian Council of Agricultural Research (ICAR), New Delhi, India for funding through the National Agricultural Science Fund (Grant number NASF/ABA-6015/2016-17/357 and NFBSFARA/BSA-4004/2013-14. The APC is funded by authors.Peer reviewe

Perception of Ticks and Tick-Borne Diseases Worldwide

In this comprehensive review study, we addressed the challenge posed by ticks and tick-borne diseases (TBDs) with growing incidence affecting human and animal health worldwide. Data and perspectives were collected from different countries and regions worldwide, including America, Europe, Africa, Asia, and Oceania. The results updated the current situation with ticks and TBD and how it is perceived by society with information bias and gaps. The study reinforces the importance of multidisciplinary and international collaborations to advance in the surveillance, communication and proposed future directions to address these challenges

Characterization of acaricide resistance in tick isolates collected from Rajasthan, India

      Rhipicephalus (Boophilus) microplus and Hyalomma anatolicum are the most common tick species infesting milk and meat producing animals throughout the country. The present study was conducted to evaluate the acaricide resistance status of the tick species to deltamethrin, cypermethrin, diazinon collected from 10 districts of Rajasthan. Characterization of resistance was carried out by adult immersion test (AIT) and larval packet test (LPT). In case of (B.) microplus resistance to deltamethrin at level I (RF = 2.5 – 4.9) in 02 isolates, at level II in 03 isolates (RF = 5.4 – 11.5) and level IV in 02 isolates (RF = 48.1 – 95.7) was detected. The resistance to cypermethrin was detected in 08 isolates of which resistance at level I in 03 isolates (RF = 2.7 - 4.58) and at level II in 05 isolates (RF = 8.05 – 16.2). Diazinon resistance was detected at level II in 06 isolates (RF = 5.8 –22.8), at level III in 01 isolates (RF = 39.0) and level IV in 02 isolates (RF = 65.9 – 66.0). While in case of H. anatolicum, the resistance to deltamethrin at level I (RF = 1.79 –2.52) in 03 isolates, to cypermethrin in 03 isolates (RF= 2.0 - 3.95) and to diazinon at level I in 03 isolates (RF = 1.32 –2.18) out of eleven isolates was detected.         A significant correlation between esterase enzyme ratio and resistant factor of tick isolates was observed with correlation coefficient (r) in α- and ß-esterase activity. The coefficient of determination (R2) for α- and ß-esterase activity indicated that 55.9 and 50.5% data points of R.(B.) microplus isolates and 66.7 and 47.2% data points of H. anatolicum isolates were very close to the correlation lines.       Analysis of sequence data of 3 targeted positions of the sodium channel gene detected a cytosine (C) to adenine (A) nucleotide substitution (CTC to ATC) at position 190 in domain II S4–5 linker region of para-sodium channel gene in 3 isolates and in reference deltamethrin resistant IVRI-IV line.      The western dry region and central plateau hills region revealed higher density of resistant ticks where intensive crossbred cattle population are reared and synthetic pyrethroids and organophosphate compounds are commonly used. The data shows an urgent need of revisiting the tick control strategy implemented through concerned government/non-government agencies

Physically unclonable function based on domain wall memory and method of use

A system and method for providing a physically unclonable function (PFU) is described. In operation, the method includes applying a domain wall shift pulse challenge to a plurality of nanowires of a domain wall memory (DWM) array, wherein the nanowires of the domain wall memory (DWM) array have process induced variations, resulting in pinning potentials which affect the velocity of the domain walls along the length of the nanowires. Following the application of the domain wall shift pulse, the response to the challenge is determined by measuring the response of the plurality of nanowires of the domain wall memory to the applied domain wall shift pulse challenge to provide a physically unclonable function (PUF) for the integrated circuit

Subolesin: A candidate vaccine antigen for the control of cattle tick infestations in Indian situation

Identification of cross-protective tick vaccine antigens is a challenging area of veterinary research. To address this challenge, a recently identified candidate tick protective antigen, Subolesin (SUB), was targeted in this research. The conservation of subolesin ortholog of Hyalomma anatolicum and Rhipicephalus (Boophilus) microplus across different Indian strains was 98.1-99.4% (within species), while at the amino acid level SUB sequence homology was ≥53.2% (between tick species). Recombinant R. (B.) microplus SUB (rBmSu) was produced in Escherichia coli and characterized. Cross-bred cattle male calves (N= 10) were immunized with three doses of 100. μg each of the rBmSu emulsified in 10% Montanide 888 at monthly intervals on days 0, 30 and 60. The control group was injected with PBS in 10% Montanide 888. For the first tick challenge, calves were infested with larvae of R. (B.) microplus generated from 100. mg eggs 2 weeks after last immunization (day 75). The immunization resulted in 16.3%, 8.0%, 9.4%, and 26.1% reduction in female tick numbers (DT), weight (DW), oviposition (DO) and egg fertility (DF), respectively, when compared to controls. In the subsequent challenge on day 105, DT, DW, DO and DF were reduced by 9.0%, 4.1%, 8.6%, and 24.2%, respectively, when compared to controls. The vaccine efficacy (E) was equal to 44.0% and 37.2% after the first and second challenges, respectively. The results showed a positive correlation between antibody titers for both total IgG and IgG1 and E in the second but not in the first tick challenge. These results suggested the possibility of developing a SUB-based vaccine for control of cattle tick infestations under Indian conditions.Senior author is highly thankful to the Indian Council of Agriculture Research (ICAR) for providing Senior Research fellowship.Peer Reviewe

Comparative efficacy of rHaa86 and rBm86 against Hyalomma anatolicum anatolicum and Rhipicephalus (Boophilus) microplus

Hyalomma anatolicum anatolicum and Rhipicephalus (Boophilus) microplus are the most economically important tick species in India and other tropical and subtropical regions of the world and transmit pathogens causing animal and human diseases. We demonstrated that vaccination of animal by rHaa86 could be used for the control of both H. a. anatolicum and R. (B.) microplus infestations. By comparing the efficacy of rHaa86 and rBm86, it was observed that vaccine based on rHaa86 will be more effective in controlling homologous challenge infestations (68·7% against larvae and 45·8% against adults). The results of this trial demonstrated that species-specific antigens are the better choice for vaccine development and could serve as an effective tool for the integrated control of H. a. anatolicum.The work has been facilitated through the International Consortium on Ticks and Tick borne Diseases (ICTTD3), financed by the International Cooperation Programme of the European Union through Coordination Action Project No. 510561. This work was financially supported by Indian Veterinary Research Institute.Peer Reviewe

Control of ticks of ruminants, with special emphasis on livestock farming systems in India: Present and future possibilities for integrated control - A review

India is predominantly an agricultural country with about 70% of her population dependent on income from agriculture. Although India accounts for a significant share of world’s livestock resources, livestock production is greatly affected by ticks and tick-borne diseases (TTBDs). Therefore, India represents a particularly interesting scenario for the study of TTBDs. Herein, we review the problems and opportunities for the integrated control of ticks of ruminants with special emphasis on livestock farming systems in India. Developments discussed in the review in the area of tick vaccines and other tick control measures should have an impact on the future of Indian livestock production.This work has been facilitated through The Integrated Consortium on Ticks and Tick-borne Diseases (ICTTD-3), financed by the International Cooperation Programme of the European Union through Coordination Action Project no. 510561.Peer reviewe

Cloning, expression and immunoprotective efficacy of rHaa86, the homologue of the Bm86 tick vaccine antigen, from Hyalomma anatolicum anatolicum

The Bm86 homologue of Hyalomma anatolicum anatolicum Izatnagar isolate was cloned and expressed in methylotropic yeast Pichia pastoris as intracellular, glycosylated and particulated form. It was named as rHaa86, the first recombinant protein of H. a. anatolicum. Seven epidermal growth factor-like domains predicted in Haa86 were structurally similar with that of its Bm86 counterpart. The identity between the corresponding EGF like domains of Bm86 and Haa86 were ranging from 51·3% to 78·3%. The molecular weight of the rHaa86 was 120–140 kDa, with possible 50–70 kDa glycosylation. The purified rHaa86 was characterized immunologically and evaluated for its immunoprotective potential against homologous challenge infestation in three groups of cross-bred calves. The immediate rejection percentage of females of H. a. anatolicum was 36 5%, 12·4% and 10·1% fed on immunized (group 1), adjuvant control (group 2) and untreated control (group 3) calves, respectively. The percent rejection of female ticks fed on immunized calves was 24·1% and 26·4% higher than for the ticks fed on control groups 2 and 3, respectively (P < 0·05). The reduction of number of females, mean weight of eggs, adult females and efficacy of immunogen were 58·0%, 9·0%, 5·0% and 61·6%, respectively. The mean reproductive index of females fed on group 1 calves was significantly lower (P < 0·05) than the females fed on the control groups and 44% reduction in the number of engorged larvae was recorded from the group 1 calves. The data demonstrated that rHaa86 antigen based vaccine could serve as one of the effective components in the integrated control of H. a. anatolicum.Authors are grateful to Indian Council of Agricultural Research, New Delhi for providing research fellowship to the Senior author. Sincere thanks are due to Department of Biotechnology, Government of India for providing financial support. This work has been facilitated through the Integrated Consortium on Ticks and Tick-borne Diseases (ICTTD-3), financed by the International Cooperation Programme of the European Union through Coordination Action Project no. 510561.Peer reviewe