BackgroundThe New World screwworm, Cochliomyia hominivorax, is a devastating pest of livestock endemic to subtropical and tropical regions of the Western hemisphere. The larvae of this species feed on the tissue of living animals, including man, and can cause death if untreated. Over 60 years ago, the sterile insect technique (SIT) was developed with the aim of eradicating this pest, initially from Florida but subsequently from all of North and Central America. From the outset it was appreciated that SIT would be more efficient if only sterile males were released in the field, but this was not possible until now.ResultsHere, we report on the development and evaluation of the first sexing strains of C. hominivorax that produce only males when raised on diet without tetracycline. Transgenic lines have been developed that possess a tetracycline repressible female-lethal genetic system. Ten of these lines show high female lethality at the late larval/pupal stages and three of them present dominant female lethality. Most of the lines were comparable to the wild type parental strain in several fitness parameters that are relevant to mass rearing in a production facility. Further, three lines performed well in male mating success and male competition assays, suggesting they would be sexually competitive in the field. Consequently, one transgenic line has been selected by the New World Screwworm Program for evaluation under mass rearing conditions.ConclusionsWe conclude that the promising characteristics of the selected sexing strains may contribute to reduce production costs for the existing eradication program and provide more efficient population suppression, which should make a genetic control program more economical in regions were C. hominivorax remains endemic.Electronic supplementary materialThe online version of this article (doi:10.1186/s12915-016-0296-8) contains supplementary material, which is available to authorized users.

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.

Extracts were prepared from leaf, bark, and seed of Azadirachta indica, leaf and seed of Prunus persica, bark of Mangifera indica, and leaf of Psidium guajava and were evaluated against Boophilus microplus. Of the eight extracts screened, the extracts prepared from the A. indica seed showed very high level of efficacy (80%) after 5 h of treatment. Besides the immediate effect on adult ticks, the egg-laying properties of the survived ticks was also assessed, and a significant reduction (P < 0.01) in the reproductive index of ticks fed on animals treated with A. indica seed extracts was noted in comparison to control. The efficacy of the neem seed extracts was compared with the commonly used synthetic pyrethroids, and comparable efficacy against B. microplus fed on animals treated with neem seed extracts and acaricide treated was noted. The possibility of using the extracts in IPM format for the management of ticks is discussed.

Hyalomma anatolicum anatolicum is a three-host tick which transmits Theileria annulata infection in Indian cattle. Laboratory rearing of ixodid ticks is an essential requirement of any laboratory engaged with research on ticks and tick borne diseases. The Entomology laboratory of Indian Veterinary Research Institute is fully equipped with all the facilities and skilled manpower to maintain a homogenous H. a. anatolicum population throughout the year. The continuous supply of eggs, larvae and adults of H. a. anatolicum is maintained to meet out the demand of different experiments viz., preparation of tick antigens for immunization of animals, experimental challenge, isolation of genomic DNA and RNA. Maintenance of a H. a. anatolicum colony free of T. annulata infection is imperative for the experimental challenge infestation on cross-bred (Bos indicus x B. taurus) calves, in order to prevent the transmission of T. annulata infection to the experimental animals. A system has been developed in the laboratory in which the larvae of H. a. anatolicum were fed on New Zealand white rabbits and the dropped fed nymphs molted to adults are fed on cross-bred calves free of T. annulata infection. This synthetic cycle prevents the transstadial transmission of T. annulata as the rabbits are unsusceptible to T. annulata infection and only the adults were fed on cross-bred animals. Moreover, absence of transovarial transmission of T. annulata prevents the chance of carry over infection to experimental animals in the next cycle.

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.

The horn fly, Haematobia irritans, is one of the most economically important pests of cattle. Insecticides have been a major element of horn fly management programs. Growing concerns with insecticide resistance, insecticide residues on farm products, and non-availability of new generation insecticides, are serious issues for the livestock industry. Alternative horn fly control methods offer the promise to decrease the use of insecticides and reduce the amount of insecticide residues on livestock products and give an impetus to the organic livestock farming segment. The horn fly, an obligatory blood feeder, requires the help of microflora to supply additional nutrients and metabolize the blood meal. Recent advancements in DNA sequencing methodologies enable researchers to examine the microflora diversity independent of culture methods. We used the bacterial 16S tag-encoded FLX-titanium amplicon pyrosequencing (bTEFAP) method to carry out the classification analysis of bacterial flora in adult female and male horn flies and horn fly eggs. The bTEFAP method identified 16S rDNA sequences in our samples which allowed the identification of various prokaryotic taxa associated with the life stage examined. This is the first comprehensive report of bacterial flora associated with the horn fly using a culture-independent method. Several rumen, environmental, symbiotic and pathogenic bacteria associated with the horn fly were identified and quantified. This is the first report of the presence of Wolbachia in horn flies of USA origin and is the first report of the presence of Rikenella in an obligatory blood feeding insect.

In an attempt to develop vaccine against Hyalomma anatolicum anatolicum, the protective efficacy of rHaa86 was evaluated against experimental challenge infestations of homologous tick species and lethal dose of Theileria annulata. Following challenge, a significant difference of 20.9% (P < 0.01) in the dropping per cent of ticks fed on immunized and control animals was recorded. A statistically significant reduction of 49.6 mg (P < 0.01) in the weight of ticks fed on immunized animals in comparison with control was noted. The ticks dropped from immunized animals laid fewer eggs and a reduction of 68.1 mg (P < 0.05) in comparison with the ticks fed on control animals was noted. The DT%, DO%, DR% and E% were calculated as 73.8, 31.3, 15.8 and 82.3% respectively. In all the calves fever (rectal temperature

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