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2. Family Argasidae (Soft Ticks)(185 species, 4 genera)Characteristics: - Dorsoventrally flattened. - Usually round or oval in outline - Wrinkled integument with fine tubercles or grandulation. - Absent of scutum (dorsal shield) - Mouth parts (Capitulum) situ
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6. Genus: Argas A.persicus
7. The presencce of round discs on the dorsal side.
Adult have four pairs of legs. Each leg consists of: coxa, trochanter, femur, tibia, metatarsus and tarsus which carry Hallers organ. The leg end with two claws and one pad.
No obvious sexual differences.
- Male and female capable of enumerous expansion during the blood meal
9. Tick borne relapsing fever It is the only important disease transmitted to human by soft ticks.
Ocure in tropics, subtropics, North America and Europe.
It is caused by 15 different species of Borrelia, The most common B. duttonii which is transmited by Ornithodoros moubata.
10. Life cycle Spirochets ingested in blood meal multiply in the mid-gut, penterate the gut wall and pass into the haemocoel where they multiply and invade all tissues and organs of ticks body. After 3 days they infect salivary gland, coxal organ and ovaries.
During feeding excess body fluid are filtered from the haemocoel by the coxal organs. Then spirochets enter the host through the puncture of ticks bites or through intact skin.
11. Tansovarial transmission: spirochaets in ovaries passed to eggs so newlly hatched larva, nymph, adult (both sexes) will be infected.
Transtadial transmission: infection of larva passed to nymphal or nymphal to adult.
12. Ornithodoros savignyi Phylum: Arthropoda Subphylum: Chelicerata Class: Arachnida Order: Ixodida Family: Argasidae Subfamily: Ornithodorinae Genus: Ornithodoros
Species: savignyi
13. Ornithodoros savignyi Large in size.
Rough skin (presence of mammillae).
Tow eyes present on lateral sides (some individuals have four eyes).
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Dorsal view Ventral view
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20. Morphological differences hard ticks soft ticks