Ecto-parasites including ticks, lice, mites and fleas , play an important role in the transmission of certain diseases They are also one of the most important causes of loss in production and mortality of animals in various part of the country through decrease in production and reproduction, down grading and rejection of skins and 35% of sheep and 56% of goat skin rejections are attributed to ectoparasites. All these established facts imply that ectoparasites pose serious economic losses to the farmer, the tanning industry and the country as a whole The important external parasites which cause noticeable lesion in the skin coat includes ticks, lice, fleas and mange mites.
Ticks can be directly debilitating to ruminants causing mechanical damage and it may cause anemia, toxicity and paralysis in severe infestation
Ticks are separated in two main families: the Argasidae family or soft ticks and the Ixodidae also known as hard ticks. However, some researchers support the existence of a third tick family, the Nuttalliellidae which includes only a single species, found in swallow nest in North Africa Ticks and especially those of the Ixodidae family are of veterinary importance not only because they cause direct harm to the skin and the tissues of the host, but also because they transmit various pathogens. The economically most important ixodid ticks of livestock are belong to the sub genus Boophilus and the genera Rhipicephalus, Haemaphysalis, Amblyomma and Hyalomma
The ecology of ticks, the outcome of their interactions with their natural environment is fundamental to the spatial and temporal variation in the risk of infection by tick-borne pathogens. Due to the biology of ticks as blood-feeding parasites, their physical environment includes the host itself. This biotic environment reacts to the tick’s presence in both the short and the long term in ways that the abiotic environment cannot do, imposing physiological, population and evolutionary pressures on ticks. Tick distribution and their population vary according to their adaptability to ecology, eco-climate, microhabitats, ambient temperature, rainfall and relative humidity which is critical factors affecting life cycle of ticks. The relative humidity on the other hand remains an important factor for survival of ticks by regulating the water balance and prevents dehydrations.
Host relationship some ticks live in open environments and crawl onto vegetation to wait for their hosts to pass by. This is a type of ambush and the behavior of waiting on vegetation of is called questing. Thus in genera such as Rhipicephalus, Haemaphysalis and Ixodes the larvae, nymphs and adults will quest on vegetation. The tick grabs onto the host using their front legs and crawl over the skin to find a suitable place to attach and feed. Adult tick of genera Ambylomma and Hyalomma are active hunters, they run across the ground after nearby hosts
Ticks are blood sucking ectoparasites that feed on mammals, birds and reptiles. The medical and economic importance of ticks had long been recognized due to their ability to transmit disease to humans and animals in several ways and parasitize a wide range of vertebrate hosts, and transmit a wide variety of pathogenic agents than any other group of arthropods They play a major role of vector in spreading different diseases of livestock and humans such as babesiosis, thileriosis anaplasmosis and many rickettsial and viral diseases. In addition, direct losses due to their being ectoparasites includes blood loss, irritations that result in “tick worry” and interrupt the grazing habits of the host. Damage and loss of udders are also caused by the attachment and feeding activities of ticks, which provide portals of entry for secondary bacterial infections and induce myiasis and tick paralysis due to the toxins they secrete in to the blood. The secreted toxins may evenly disseminate to the respiratory organs and cause death of the animal. Their attachment and feeding also down grade hides and skins and reduce milk and wool production. Reduce productivity and increase susceptibility to other disease
Ticks and the diseases they transmit are widely distributed throughout the world, particularly in tropical and subtropical regions. Losses attributable to ticks are caused either directly, through tick worry, blood loss, damage to hides and udders and the injection of toxins, or indirectly through mortality or debility caused by the diseases transmitted by or associated with the ticks
The currently available tools for tick control consist of chemical acaricides relying on treatment with different application methods and/or formulations of acaricides, tick resistant animals, tick vaccines and management interventions. The choice of acaridae formulation and method of application depends upon acaridae availability and price, the size of the farm and extent of facilities, the production system and the degree to which ticks are seen to be a problem. Small scale farming operations might achieve effective control using spray or pour-on formulations. Medium and large farms are more likely to use immersion dips or spray races. In most countries all that is attempted is reduction of the tick population by periodic dipping or spraying. Complete eradication is extremely difficult because of the persistence of ticks, especially multi-host ticks, on wild fauna and the ability of adult ticks to live for very long periods away from a host. On the other hand, continuous treatment to restrain the tick population is highly conducive to the development of resistance, a problem which has become apparent in many tick areas.
As with other farm animal species, sheep and goats should be removed from the infested pasture to avoid contact with ticks. This is not always practical and topical therapy is then used to reduce the tick population.