University:
American Career College
Course:
NURS115 | Intermediate Medical
Academic year:

2021
Views:

498

Pages:

33
Author:

Neulri

Hard ticks (Ixodidae) flattened dorsoventrally, oval in shape and about 2–23 mm long, The capitulum or ‘false head’ projects forwards from the body and is visible from above have a dorsal plate called the dorsal shield or scutum, In males the scutum is large and covers almost the entire dorsal surface of the body in females it is much smaller and restricted to the anterior part of the body both sexes take blood-meals and are therefore potential disease vectors. Ixodes, Dermacentor, Rhipicephalus, Haemaphysalis and Amblyomma.) such as Boophilus species Medical importance • Tick paralysis and allergies • Female hard ticks, mainly Dermacentor and Ixodes species, can cause tick paralysis. • Tick paralysis is not caused by pathogens but by toxins in the female tick’s saliva which are continually being pumped into the host during the tick’s long feeding period. • Arboviruses (More than 120 arboviruses • the important tickborne viral diseases of humans are spread by hard ticks. • All arboviruses are transmitted by the tick’s bite, and transovarial transmission usually occurs.) • Tick-borne encephalitis (TBE) (Flavivirus) • Omsk haemorrhagic fever (OHF) (Flavivirus) • Kyasanur Forest disease (KFD) (Flavivirus) • Crimean–Congo haemorrhagic fever (CCHF) • Colorado tick fever (CTF) (Coltivirus) • Rickettsiae • Rocky Mountain spotted fever (RMSF) (The causative agent is Rickettsia rickettsii.) • Mediterranean spotted fever (The infective agent is Rickettsia conorii) • African tick-bite fever • tick-borne typhuses • Q fever (is a rickettsial zoonotic disease caused by Coxiella burnetii.) • Human ehrlichiosis • Spirochaetes: Lyme disease(It is caused by the spirochaete Borrelia burgdorferi) • Tularaemia (is a bacterial disease caused by Francisella tularensis) Control • application of repellents • The recommended procedure is to grasp the tick as close as possible to the host’s skin with blunt forceps and slowly pull the tick out. Scabies mites (Sarcoptidae) mites • have eight legs • absence of teeth on the hypostome of the mouthparts • Dorsally the mite has numerous tiny spines and a few bristles (setae) • pale and disc-shaped Adult male scabies mites are small and presence of ‘suckers’ on the last pair of legs The fertilized female then digs and eats her way into the surface layers of the skin – the stratum corneum, selecting places where the skin is thin and wrinkled, between the fingers and on the wrists, elbows, feet, penis, scrotum Scabies is a contagious complaint which is transmitted only by close contact. Recognition of scabies • female mite’s tunnels; visible by smearing a drop of ink • faeces deposited in these tunnels may be visible through the skin as dark pepper-like spots. • Surface layers of skin at the ends of the tunnels can be gently scratched away with sharp needles Treatment of scabies • Permethrin creams are usually the first choice for treating scabies, but there needs to be care with using permethrin on pregnant women and children • Benzyl benzoate has been used for many years, and may still be appropriate • Scabies is highly contagious, so it is important to treat all family members Demodicidae: follicle mites (Demodex species) D. folliculorum is worm-like, with tiny claws, a semi-transparent, elongated organism MRTwww.Win2Far Company Logo • Demodex folliculorum (0.2–0.4mm long) • primarily inhabits hair follicles and eyelash hair follicles • feed on subcutaneous tissues, especially sebum, and are particularly common on the forehead, nose, eyelids and cheeks adjacent to the nose. • The entire life cycle of D. folliculorum takes place in the time span of 18–24 days on its host. • During the day, they feed on dead skin cells within hair follicles. • At night, they emerge onto the surface to mate and lay eggs in hair follicles. • A female adult lays 20–24 eggs in a single hair follicle • occasionally mites cause eruptions on the face such as acne, impetigo or blepharitis. • Repeated daily washing with a diluted baby shampoo or sulphur soaps followed by antibiotic cream may reduce infections, especially around the eyelashes. For more serious cases, zinc and sulphur creams have been used, CONTROL OF INSECTS AND ACARINES Chemical Control of Vectors • Insecticides are classified according to their chemical structure. • Organochlorines • Phosphorothioate Insecticides • Carbamates • Pyrethroid Insecticides Environmental Management for Vector Control • The environment like • water and temperature, other factors such as humidity, vegetation density, patterns of crop cultivation, and housing may be critical to the survival of the different species of disease-carrying vectors. Biological Control of Mosquitoes • It is relatively natural and host specific • Natural biological control is vector reduction caused by naturally occurring biotic agents. Genetic Control of Vectors • STERILE INSECT TECHNIQUE (SIT) • INHERITED STERILITY Immunological Control of Vectors • Development of antiarthropod vaccines reduces blood-feeding and/or pathogen transmission.

Hard Ticks (Ixodidae)

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