Exam 4 Flashcards
Dermatobia hominis
- Human bot fly
- Mexico to South America
- Africa, East and Central Europe
- Eggs layed on bodies of captured arthropods
Cochliomyia hominovorax
- Primary screwworm New World
- Mexico to South America
- Africa, East and Central Europe
- Eggs layed on bodies of captured arthropods
Sucking Louse: Symptoms
Vagabond’s disease
- Affected individuals show a generalized bronze pigmentation and hardening of the skin
Short definition: Louse
Wingless parasitic insects
Suborder - Anoplura - Sucking lice
- Pediculus humanus capitis – head louse
- Phthirus pubis – pubic/crab louse
- Pediculus humanus humanus – body louse
Sucking louse: symptoms
Crab lice can produce __
Charactristic “Blue spots” which are often seen around the eyes of individuals with infested eyelashes
Pediculus humanus capitis - head louse
- Preschool and elementary age children
- Transmission by fomites (hats, bedding - less common than body lice)
Sucking Louse
Pediculus humanus humanus - body louse
- Live and lay eggs on clothing and bedding
- ONLY move to the body for blood meal
- Spread by close personal contact, crowded living conditions, poor hygiene
- Human only hosts - animal/pets no role
- Vectors for Rickettsia prowazekii, Bartonella quintana and Borrelia recurrentis (louse-borne relapsing fever)
Body louse
Pediculus humanus humanus: Treatment
- Pediculicide = medicine that kills lice
- Ovicidal = kills nit, eggs
- Improving personal hygiene
- Clothing, bedding, and towels used by infested person laundered (water at least 130°F) and machine dried w/ hot cycle
- Possible pediculicide, but generally not necessary if hygiene is maintained and items are laundered appropriately at least once a week
Head lice
Pediculus humanus capitis: Treatment
- Treatment is reccommended for active infestation:
- -Household members, close contacts should be checked and possibly treated
- Nit combs w/ teeth spaced close enough can be effective if used throughly and repeated. All nits must be removed to prevent re-infestation
Over the counter: - Pyrethrins
- Permethrin lotion
- Both kill live lice, not eggs/nits - 2nd treatment 9-10 day later
Prescription - Benzyl alcohol: kills lice, not eggs/nits - 2nd treatment 7 days later
- Ivermectin lotion: Kills lice, prevents new nymphs, no treatment consultation
- Malathion: Kills live lice, partially kills eggs (ovicidal)
Phthirus pubis - pubic/crab louse
- Most common transmission is person to person via sexual contact w/ infested individual
- Fomites (bedding/clothing) may play minor role but rare
- Most asymptotic or tickling feeling, itching caused by allergic reaction to louse saliva and irritablilty
- Pruritis caused bites of pubic lice may be very intense
- “Blue spots”
- Discoloration of skin if infestation left untreated for long time
Pubic/ Crab louse
Phthirus pubis: Stages, Infectious and Diagnostic stages
- Egg, Nymph, Adult
- Infectious: Adult
- Diagnostic: 3rd Nymph
Pubic/crab louse
Phthirus pubis: Treatment
- Over counter: Lotion containing permethrin or mousse containting pyrethrins and piperonyl butoxide
- Prescription:
- Lindane shampoo can kill lice and lice eggs. NOT first line therapy as can be toxic to the brain and other parts of the nervous system
- Malathion kills lice and some live eggs BUT not FDA approved for treatment of pubic lice
- Topical and oral ivermectin THOUGH only topical ivermectin lotion FDA approved for lice treatment
Pediculosis - Body and head: Stages, Infectious and Diagnostic
- Egg, Nymph, Adult
- Infectious stage: Adults
- Diagnostic stage: Egg
Cimicidae - Bed bugs
- Blood feeding ectoparasites, human preferred
- Naturally-infected with blood-borne pathogens, NOT effective vectors of disease
- Inflammation associated w/ their bits (allergic response saliva)
- Adults live 6-12 months and may survive long periods of time w/out feeding
- Infestation near sleeping areas
- Appearing at night or in dim light to feed on a sleeping host
- Bed bugs possess stink glands and emit distinctive odor
Bed bugs
Climex lectularius
- Urban distribution
Bed bugs
Climex hemipterus
- Tropics and Subtropics
Bed bugs
Cimicidae: Treatment
- Antibiotics for secondary bacterial infection from scratching
- Antihistamines, corticosteroids, and epinephrine have been used for bite reactions w/ varying results
- Severe cases, topical steroid creams w/ or w/out systemic anti-H1 receptor antihistaminics may be given
Elimination of infestation: - High heat:
- an hour 45°C for clothing and other materials
- Death on contact using heat at 82°C
- Vaccum frequently
- EPA approved insecticide, most are resistant
Sarcoptes scabei
- Human itch mite
- Transmission : impregnated females, person to person, skin to skin contact, and fomites
- Found between fingers and on wrists
Sarcoptes scabei: Treatment
- Ivermectin Metrifonate
- Blocking neutrotransmitters and changing membrane permeability
Protozoa
Pseudopods
- Extensions of cell that flow in direction of travel
Protozoa
Flagella
- Long whip-like extensions
Protozoa
Cilia
- Several short protusions beat rhythmically to propel
Protozoa
Trophozoites
- The feeding, motile stage of protoza
Protozoa
Cysts
- Infectious stage of protozoa, highly condensed cytoplasm and thick cell wall, resistant to enviromental changes
Protozoa - Reproduction
Asexual reproduction
Most common
Sexual reproduction
Gametocytes fuse to form a diploid zygote
Protozoa - Reproduction
Conjugation
- Two cells exchange nuclei
Protozoa - Reproducton
Schizogony
- Special form of asexually reproduction, multiple mitoses, multi nucleate cell called schizont
Amoebozoa
- Lobe shaped pseudopods, no shells
Rhizaria
Threadlike pseudopods, aquatic isolates, porous shells
Protozoa
Karyosome
Concentrated clumps of chromatin in nucleus
Peripheral chromatin
- Non active chromatin
- Halo-like
Apicomplexa
- Alveolates
- Gliding motility
- Penetration of host cell
Metamonada: Parabasalids
- Flagellated protozoa
- Lack mitocondria
- Single nucleus
- Parabasal body
Metamonada: Diplomonadida
- Mitosomes
- Two nuclei
- Giardia
- Lack gogi bodies
- Multiple flagella
Kinetoplastids - Euglenozoa
- Single large mitochindria
- Kintoplast
Trypanosome
- Slender, flagellate protozoan found in blood
Kinetoplastids - Euglenozoa
Leishmania
- Round or oblong flagellate protozoan found in blood
- Also called promastigote or amastigote
Intestinal Protozoa
Amoebae
- Naked, loose, pseudopod-forming
- Abundant soil dwellers, rich organic debris
- Motile
Entomoeba
