Introduction to Medical Entomology Flashcards
How many % of all animals are arthropods?
85%
What are the defining attributes of arthropods?
- Bilateral symmetry
- Hard exoskeleton
- Jointed appendages
- Segmented bodies
What is the scientific term for segmentation?
Tagmata
Which class has 1 pair of legs per body segment and head & trunk divisions?
Chilopoda
Which class has 2 pairs of legs per body segment and head & trunk divisions?
Diplopoda
Which class has 5 pairs of legs and no distinct segmentation?
Crustacea
Which class has 4 pairs of legs (3 in larvae) and cephalothorax & abdomen divisions?
Arachnida
Which class has 3 pairs of legs and head, thorax and abdomen divisions?
Insecta
Which class has no legs in adults but 2 in the larval form?
Pentastomida (extinct)
What are the two types of vectors?
Biological and Mechanical
How long do mosquitoes stay in the egg stage? How many larval stages do they have?
1 - 2 days; 4
What are the our important genera of mosquito?
- Aedes
- Anopheles
- Mansonia
- Culex
Characteristic of Anopheles mosquito egg-laying
Eggs are laid parallel to surface due to absence of larvae’s siphon.
Primary difference between male and female mosquitoes
Antennae
Plummose - Male
Pinnose - Female
Primary urban mosquito vector
Aedes aegypti
Primary rural mosquito vector
Aedes albopictus
Differentiate A. aegypti and A. albopictus
A. aegypti - lyre shaped thorax with white stripes
A. albopictus - straight white line marking thorax
What is the primary mosquito vector responsible for transmitting malaria in the Philippines?
Anopheles flavirostris (clear, slow-flowing water)
How do you distinguish Anopheles mosquito from other genera?
While feeding, its abdomen points upward.
What are the secondary mosquito vectors of malaria?
- A. litoralis (brackish water)
- A. balabacensis (still water in forest in Palawan)
- A. mangyanus (same as A. flavoristris)
- A. maculatus (elevated areas)
What vectors transmit Bancroftian filariasis caused by Wuchereria bancrofti?
- Anopheles flavirostris
2. Aedes poecilius (primary; breed in axils)
What vectors transmit Brugian flariasis caused by Brugia malayi?
- Mansonia bonneae (swamp breeder)
2. Mansonia uniformis (swamp breeder)
What causes Bancroftian filariasis?
Wuchereria bancrofti
What causes Brugian flariasis?
Brugia malayi
What is the global primary vector for Japanese encephalitis? Where do they breed?
Culex tritaeniorhynchus; rice
What is the primary vector of Japanese encephalitis in Indonesia?
Culex quinquefasciatus
What are the other vectors of Japanese encephalitis?
- C. gelidus
- C. pseudovishnui
- C. vishnui
- C. fuscocephala
How deep should the water be for mosquito larvae to survive?
2 cm
Describe breeding habit of Aedes mosquitoes
- Container or axil breeders
- Clear but not clean and stagnant water
- Eggs survive for six months w/o water
Describe breeding habit of Anopheles mosquitoes
Clear, clean and slow flowing partly shaded streams
Describe breeding habit of Mansonia mosquitoes
Swampy and forested areas with aquatic vegetation
Describe breeding habit of Culex mosquitoes
Rice field, pools, irrigation canal, trapped water or undisturbed fish pond
Is transmission via oral secretion a characteristic of mechanical vectors?
Yes
What do you call the fine hairs that may harbour pathogens?
Setae
What has been found to be viable in cockroach gut for 12 house?
Mycobacterium leprae
What types of diseases can cockroaches carry?
Tuberculosis, cholera, leprosy, dysentery, diarrhea, anthrax, poliomyelitis and typhoid
What is the 2nd most important ingested allergen?
Cockroach parts
What species of cockroach is common in condominiums and prefers cold areas?
Blatella germanica or German cockroach
What species of cockroach is eaten as a delicacy?
Periplaneta americana or American cockroach
What are fleas in Filipino?
Pulgas
Enumerate the common species of fleas
- Pulex irritans (humans)
- Ctenocephalides canis (dogs)
- Ctenocephalides felis (cats)
- Xenopsylla cheopis (rats)
- Tunga penetrans (chigoe/sand mites; causes tungiasis)
Characteristic of flea infestation
Zigzag pattern of bites
Which flea may serve as a vector for murine typhus and the plague?
Xenopsylla cheopis
What do members of genus Ctenocephalides often harbour? What does it cause?
Dipylidium caninum; dypylidiasis
What does the Oriental rat flea typically carry? What does it cause?
Hymenolepis diminuta; hymenolepiasis
Which larvae look like rice grains?
Flea larvae
Enumerate the common species of lice
- Pediculus humanus capitis
- Pediculus humanus humanus
- Phthirus pubis
Differentiate the lice species based on biting habit.
Body Louse - Night
Head Louse - Day
Pubic Louse - Day/Night
Differentiate the lice species based on residual effects of bites.
Body Louse - Hyperpigmentation
Head Louse - Isolated pustules
Pubic Louse - Bluish spots
Pediculosis is the ___ most common ailment among public school children aged _____.
2nd; 7 - 12
What are important diseases transmitted by body lice?
- Epidemic typhus
- Trench fever
- Louse-born relapsing fever
What is the etiologic agent of Trench fever?
Bartonella quintana
List possible modes of treatment for lice infestation.
- 1% gamma benzene hexachloride (lindane)
- 1% permethrin cream (pyrethrin)
- 0.3% pyrethrins + 3% piperonyl butoxide shampoo
What are the Filipino terms for mange mite?
Tungaw, kurikong or galis-aso
What is the only parasitic species of mite?
Sarcoptes scabiei var. hominis
Scabies is also known as?
Seven-year itch, sarcastic acariasis or Norwegian itch
How deep to S. scabiei burrow into people’s skin?
2.5 cm
What are the top 3 skin diseases?
- Tinea flava
- Skin allergies
- Scabies
What is the treatment for mange mites?
- 12 hours of gamma benzene hexachloride
- 12 hours of 25% benzyl benzoate
- 24 hours for 2 weeks of crotamiton
- Antihistamines/salicylates (pruritus)
- Antibiotics
- Sulfur soaps
Kissing bugs are also known as?
Conensoses or assassin bugs
What family do kissing bugs belong to?
Reduviidae
Enumerate common species of kissing bugs
- Rhodnius prolixus
- Panstrongylus megistus
- Triatoma infestans
Characterize the bites of kissing bugs
- Painful
- May involve fever and anaphylactic reactions
- Nighttime
Kissing bugs may be vectors for what? What does this organisms cause?
Trypanosoma cruzi; Chaga’s disease or American trypanosomiasis
What do you call the infestation of living tissue by fly larva?
Myiasis
What are the categories of myiasis?
- Semispecific
- Accidental
- Specific
Enumerate the genera involved in semispecific myiasis
- Sarcophaga (fleshfly)
- Lucilia (bangaw)
- Calliphora (blowfly)
Enumerate the genera involved in accidental myiasis
- Musca domestica (housefly)
2. Fannia (latrine fly)
Enumerate the genera involved in specific myiasis
Dermatophobia hominis (human botfly)
What are the main steps in fly control?
Exclusion, Restriction and Destruction
What family are the common bedbugs part of?
Cimicidae
Enumerate common species of bedbugs.
- Cimex lectularius
- Cimex hemipterus
- Leptocimex boueti
What is most notable about cimicosis?
There is a linear biting pattern (typically 3).
What are the most venomous types of bees?
Honeybee and bumblebee
Enumerate the components of venom.
- Histamine
- Nonhydrin
- Mellitin
- Phospholipase
- Hyaluronidase
What is the difference between a bee sting and a wasp sting?
Bee sting - only once
Wasp sting - may occur multiple times
Wasp venom also has 10% acetylcholine
Enumerate the common genera of scorpions.
- Centruroides spp.
2. Buthus spp.
What are the components of scorpion venom?
- Serotonin
2. Sulfhydryl group (neurotoxic & haemolytic)
What are the clinical manifestations of being poisoned by a scorpion?
Hives, swelling, asthma, allergic rhinitis, diarrhea, nausea, vomiting metallic taste in mouth and respiratory paralysis
What family do blister beetles belong to?
Meloidae
Give a common species of blister beetle.
Lytta vessicatoria
What is the main component of blister beetle poison?
Cantharidin (has sulfhydryl group)
What is the clinical manifestation of blister beetle poisoning?
Slight tingling, burning and erythema
2 - 3 hours after - appearance of vesicles/bullae
8 - 10 hours after - appearance of elongated blisters
Drench in running water and do not rub!
What are the components of caterpillar poison?
- Histamine
- Proteinaceous substances
- Water soluble protein pytic enzyme
How do you treat caterpillar poisoning?
- Application of tape over sting site to remove spines/hairs
- Prescribe antihistamine
What arthropod found in flour and grain serves as intermediate hosts for what helminths?
Tribolium confusum or Confused Flour Beetle
- Raillietina garrisoni (Common Rat Tapeworm)
- Hymenolepis nana (Dwarf Tapeworm)
- Hymenolepis diminuta (Rat Tapeworm)
What arthropod serves as the intermediate host of Hymenolepis nana (Dwarf Tapeworm)?
Tenebrio molitor