Efficacy of Whole Crude Extract of Hard Ticks in the Treatment and Control of Tick Infestation in Livestock

The present study was designed for experimental vaccination of cattle against hard ticks using their whole crude larval extract. Thirty cattle of different age groups were randomly selected for the study and were divided into two equal groups comprising 15 in each group. Group 1 was vaccinated, while group II served as control was administered with ivermectin which is used as conventional drug. Ticks were collected from cattle of various herds in district Faisalabad. The fully engorged female ixodid ticks imbibed huge amount of blood, were counted and identified on the basis of morphological features using stereomicroscope, based on the taxonomic and structural differences of the species, different instars and sexes as described by Walker et al. (2003). Five to seven partially engorged hard ticks collected from each infested cattle and were chilled at 4◦C for 30 min and washed with 70% alcohol. Then ticks were rinsed with normal saline three times to remove the debris. The rinsed ticks were ground in ice-cold 0.15M PBS (pH 7.2) at the rate of 10 ticks per ml, and filtered through 4 layers of muslin cloth. The resulting crude tick extract was centrifuged and the supernatant was stored at -40◦C. The total protein content of the supernatant was estimated by the kit method (Ali et al., 2009; Ghosh et al., 1998; Mustafa, 2012). The vaccine was prepared using 1% formalin, 5% antibiotic (oxytetracycline, 100mg) and 40% vegetable oil in the ticks extract in this collected supernatant. Animals of Group I were vaccinated with whole crude tick extract vaccine via subcutaneous route @1ml/50 Kg body weight of the animal, in 3 successive doses at weekly interval. Group II served as control and was administered with standard acaricidal drug (ivermectin).

At the end of each week post administration of whole crude tick extract vaccine, the number of hard ticks was counted with naked eye and the efficacy of the vaccine was determined in terms of reduction in number of infesting ticks. Weight of the engorged ticks was calculated to determine the amount of blood sucked from the hosts accordingly. Control of ticks was determined on the basis of number of ticks infesting the vaccinated and control group over period of 01 month, post vaccination. Moreover, immunoglobulin G (IgG) level was detected in the animals on weekly basis using ELISA technique.

Table I shows the number of ticks counted at the end of each week on different parts of the body of the animals like udder, thighs, ear etc. Group A was administered with whole crude tick extract vaccine and Group B was treated with acaricidal drug (ivermectin) in 3 successive doses at weekly interval.

The results of the current study revealed that whole crude tick extract vaccine was more effective in the control of ticks compared to standard acaricidal drug ivermectin.

Pre-vac,before vaccination; Post-vac, after vaccination. A, administred with crude ticks extract; B, treated with ivermectin.

In group A, 78.4% ticks were significantly (P<0.05%) eliminated from different parts of the animals and in Group B the recovery/ticks elimination rate was 63.24% from the infested animals (Fig. 1). Similar studies were conducted on sheep in which Hyalomma anatolicum anatolicum were used for larval antigen preparation and administered via subcutaneous route @ 0.1ml and sheep were found resistant to ticks infestation (Mustafa, 2012). It was also reported from a study that antigen from midgut of Hyalomma anatolicum anatolicum was administered in rabbits and that maximum resistance was reported against tick infestation (H. a. anatolicum) in the immunized rabbits (Madani et al., 2008).

The hematological parameters of the cattle infested with ticks were determined and compared to the healthy cattle free from ticks (Table II). A similar study also revealed that the hematological parameters were significantly affected (P<0.001) in calves, due to tick infestations (Kaur et al., 2017).

The IgG level was determined at the end of each week and it showed significant increase i.e. 1590, 1698, 1838, 2055 and 2140 mg/dl of IgG level in the blood. At the end of 5th week, IgG level as maximum showing maximum resistant against tick infestation in cattle.

It is further added that no doubt ticks are ectoparasites, but ticks attach to the body of the host and sucks the blood that contain antibodies. A study was conducted on the similar concept of anti tick vaccine, whereby the efficacy of the Bm86 midgut antigen and the cytosolic Subolesin (SUB) antigen was evaluated in vitro (Trentelman et al., 2019) and it was concluded that R. australis larval feeding was significantly reduced. Similarly, Salp 15 antibodies were also considered effective against ticks infestations. In another study it was observed that hosts developed immune response to tick salivary proteins following repeated tick exposure that impaired tick and pathogen viability, including cutaneous inflammation and resulted in itch and an increased awareness of infesting ticks (Walker et al., 2003; Wikel, 1996).

From the present study, it has been concluded that whole crude tick extract vaccine is more effective than ivermectin in the treatment and control of ticks infestation in cattle, with better recovery rate and no harmful impacts. Moreover, the ivermectin is effective only for 2-3 weeks while crude tick vaccine is effective for long period.

The authors have declared no conflict of interest.