Upcoming and future strategies of tick control: a review.

Ticks are distributed worldwide and significantly impact human and animal health. Due to severe problems associated with the continuous use of acaricides on animals, integrated tick management is recommended. Increasing public health concern over the tick-borne diseases demands the strategic control of ticks on animals that transmit diseases to human beings. Immunological control of tick vector of Kyasanur Forest Disease (KFD) on cattle and other wild reservoir hosts is one of the possible alternative strategy for reducing the transmission of KFD to man. Chemical-vaccine synergies have been demonstrated and a combination of chemical and vaccine for tick and tick-borne disease control has been identified as a sustainable option. Studies have suggested the possibility of vaccine strategies directed towards both tick control and transmission of pathogens. Besides tick vaccine, use of endosymbionts, which are essential for the survival of arthropod hosts, for the control of tick vectors will be one of the targeted areas of research in near future. India with huge natural resources of herbs and other medicinal plants, the possibilities of developing herbal acaricides is discussed. The future of research directed towards target identification is exciting because of new and emerging technologies for gene discovery and vaccine formulation.

Cloning and sequencing of 28 kDa outer membrane protein gene of Brucella melitensis Rev. 1.

Brucella melitensis is an organism of paramount zoonotic importance. The 28 kDa outer membrane protein (OMP) is one of the immunodominant antigens of B. melitensis. The gene encoding 28 kDa OMP (omp28) has been amplified from B. melitensis Rev. 1 strain. A PCR product of 753 bp, encoding complete omp28 gene of B. melitensis, was obtained. The gene was further cloned and sequenced. The nucleotide sequence of B. melitensis Rev. 1 strain showed substitution of 2 nucleotides from that of 16M strain.

Evaluation of guinea pig model for experimental Salmonella serovar Abortusequi infection in reference to infertility.

The present study conclusively revealed the role for Salmonella enterica subspecies enterica serovar Abortusequi in conception failure. None of the 12 guinea pigs conceived when orally exposed to sublethal dose of the pathogen during breeding, while 66.67% of animals in control group were found pregnant during same period of observation under similar conditions. Salmonella carrier animals also had drastic reduction in conception rate (16.67%). During mid pregnancy, S. Abortusequi exposure to guinea pigs through intravaginal, intramuscular and subcutaneous routes induced fetal death followed by resorption. While 2 out of 6 orally inoculated and 3 out of 6 intraperitonially inoculated guinea pigs aborted, in rest of the animals fetal death was followed by meceration and resorption. It was interesting to note that S. Abortusequi could not persist longer than a week in males while in pregnant females it could be detected for >10 weeks after inoculation. In late pregnancy, most of the exposed animals aborted and non aborting animals though had normal parturition, survival rate of their babies was nearly zero in comparison to the control group. The study revealed role for S. Abortusequi in impairing conception, abortion, early fetal deaths, fetal meceration and resorption. Further studies are required to identify factors responsible for increased susceptibility of females particularly during pregnancy.

Application of polymerase chain reaction (PCR) for diagnosis of equine herpes virus-1 (EHV-1).

Fifty aborted foetus samples were diagnosed for the presence of equine herpes virus-1 (EHV-1) by polymerase chain reaction (PCR) technique. Specific primer pair for amplification of a particular segment of EHV-1 DNA in gc region having 3 Hae III restriction endonuclease sites was used. A 409 base pair segment obtained as PCR amplification product in 9 samples was digested with Hae III to confirm the presence of EHV-1 as the infectious agent in aborted tissues. It was observed that PCR technique was more sensitive, specific and rapid than the conventional virological diagnostic methods.

Single radial immunodiffusion potency test for standardization of indigenous equine influenza vaccine.

Single radial immunodiffusion (SRD) assays were used for measuring the haemagglutinin antigen contents of equine influenza vaccine prepared from an Indian virus isolate. A/Equine-2/Ludhiana/1/87 (H3N8). Five different preparations of the vaccine were standardized by SRD to prepare 913 doses, each containing 20 micrograms HA/ml-1 dose-1. This test also showed influenza virus subtype specificity as no cross reaction was observed between subtype 1 (H7N7) and subtype 2 (H3N8) viruses.

Production of monoclonal antibodies against equine influenza A/Equi-2 (H3N8) Indian isolate.

Seven hybrid cell lines of mouse myeloma cell line NSO and spleen cells of BALB/c mice producing monoclonal antibodies (MAbs) against equine influenza A/Equi-2/Ludhiana/87 (H3N8) virus were developed. These MAbs were purified, isotyped and characterised by enzyme linked immunosorbent assay (ELISA), fluorescent antibody test (FAT), haemagglutination inhibition (HI) and virus neutralization (VN) tests. The titres of ascitic fluids induced by hybridomas as estimated by ELISA ranged from 1:25,600 to 1:51,200. Monoclonality of these clones was confirmed using a panel of 5 viral antigens, each belonging to a single isotype. MAbs (5) belonged to IgM and one each to IgG1 and IgG2a. Two epitopes appeared to be closely resembling by HI and VN tests but other two epitopes appeared to be different.