27. Arthropods (bugs & flies) Flashcards
what are the two families of medical importance in order Hemiptera, in the suborder bugs?
- Reduviidae: assassin bugs, kissing bugs (carries the protozoan T. cruzi)
- Cimicidae: bed bugs
what did bed bugs evolve from?
ectoparasites of cave dwelling mammals, most likely bats
What are the three closely related species of human bed bugs?
- Cimex lectularis
- Cimex hemipterus
- Cimex boueti
humans may become _____________ hosts of Cimex species of bats and birds
incidental
what is the Cimex lectularis?
the common bed bug, with a cosmopolitan distribution
what is the Cimex hemipterus?
the indian bed bug, restricted to the tropical and sub-tropical regions
what is the Cimex boueti?
found in tropical regions of Africa and South america
where are bed bugs found?
in human habitations, including homes, hotels, dormitories, prisons, barracks, and hospitals
–> in cracks, furniture etc
what time of day do bed bugs appear?
at night or in dimlight to feed on a sleeping host
how many times do bed bugs bite?
characteristically bite two or three times in succession over a period of a few minutes
what do bed bugs inject when feeding?
salivary fluids (anti-coagulants and anaesthetics), thereby sensitizing the hist
- repeat exposure may cause a delayed reaction
the larvae are the _______
nymphal stages
how many nymphal stages do the bed bugs have?
5
are bed bugs effective vectors of disease?
no, although they have been found naturally infected with blood borne pathogens
what is the primary medical importance associated with bed bigs?
inflammation associated with their bites (due to allergic reactions to components in their saliva)
what is the treatment for bed bugs?
the bites are usually self limiting, and require little attention other than antiseptic creans or lotions to prevent infection at the bite site
what do biting midges transmit?
filariid nematodes
what do sandflies transmit?
Leishmaniasis
what do black flies transmit?
Onchocerciasis
what do mosquitoes transmit?
- malaria
- filariasis
what do horseflies and deerflies transmit?
filarial eye worm, Loa loa
what do the Tse tse flies transmit?
african sleeping sickness
what are the diptera?
winged flies
do all diptera adult flies inflict damage by biting/while seeking blood?
no
the larvae of several families of diptera are ________ during development, livinhg within the tissue of the infected host
pathogenic
what are the flies that require living tissue for development?
obligate parasites
what is myasis?
burial of larvae in tissue - is an obligatory step in the life cycle of some flies and incidental for others
where are the tissues in which myasis can occur?
cutaneous arterial intestinal urinary - normal tissue or in preexisting wounds, some of which result from other infection
what do the larvae of diptera use to burrow through nectrotic tissues or healthy tissues?
their mandibular hooks aided by proteolytic enzymes
what stage of flies causes myasis?
the larval stage (maggots) of various flies
Dermatobia hominis is the primary human ________
bot fly
Cochliomyia hominivorax is the primary _________ in the New World.
screw worm fly
Chrysoma bezziana is the ________
old world screw worm
Cordylobia anthropophaga is known as the ________
tumbu fly
after how long do the bot fly larvae hatch?
5-10 weeks
what is the hole in the skin made by the bot fly?
an air hole for the posterior spiracles
what are the posterior spiracles?
the respiratory organs - a series of external openings
where do new world screw worms lay their eggs?
around the edges of wounds
what do the larvae of screw worms invade?
wounds, after the eggs have been laid near the wounds
can a large or small number of screw worm larvae infest a wound?
a large numebr
what do the old world screw worms invade?
the larvae penetrate wounds or mucous membranes, primarily affecting areas around the eyes, mouth and nose
what do tumbu flies cause?
accidental myasis
where do tumbu flies lay eggs?
on contaminated soil with urine or feces
what do emerging larvae of tumbu flies attach themselves to?
any host they come in contact with and penetrate the skin
what are infestations with D. hominis (bot fly) characterized by?
cutaneous swellings on the body or scalp that may produce discharges and be painful
what is different in infestations with C. homnivorax?
they can be more serious,as this species may travel through living tissue in the body and not stay subdermal like most of the other species of flies that cause myiasis
what else can occur with infection of D. hominis or C, homnivorax
secondary bacterial infection
what are the diptera?
winged flies
do all diptera adult flies inflict damage by biting/while seeking blood?
no
the larvae of several families of diptera are ________ during development, livinhg within the tissue of the infected host
pathogenic
what are the flies that require living tissue for development?
obligate parasites
what is myasis?
burial of larvae in tissue - is an obligatory step in the life cycle of some flies and incidental for others
where are the tissues in which myasis can occur?
cutaneous arterial intestinal urinary - normal tissue or in preexisting wounds, some of which result from other infection
what do the larvar of diptera use to burrow through nectrotic tissues or healthy tissues?
their mandibular hooks aided by proteolytic enzymes
what stage of flies causes myasis?
the larval stage (maggots) of various flies
Dermatobia hominis is the primary human ________
bot fly
Cochliomyia hominivorax is the primary _________ in the New World.
screw worm fly
Chrysoma bezziana is the Old World ________
screw worm
Cordylobia anthropophaga is known as the ________
tumbu fly
after how long do the bot fly larvae hatch?
5-10 weeks
what is the hole in the skin in a bot fly?
an air hole for the posterior spiracles
what are the posterior spiracles?
the respiratory organs - a series of external openings
where do new world screw worms lay their eggs?
around the edges of wounds
what do the larvae of screw worms invade?
wounds, after the eggs have been laid near the wounds
can a large or small number of screw worm larvae infest a wound?
a large numebr
what do the old world screw worms invade?
the larvae penetrate wounds or mucous membranes, primarily affecting areas around the eyes, mouth and nose
what do tumbu flies cause?
accidental myasis
where do tumbu flies lay eggs?
on contaminated soil with urine or feces
what do emerging larvae of tumbu flies attach themselves to?
any host they come in contact with and penetrate the skin
what are infestations with D. hominis (bot fly) characterized by?
cutaneous swellings on the body or scalp that may produce discharges and be painful
what is different in infestations with C. homnivorax?
they can be more serious,as this species may travel through living tissue in the body and not stay subdermal like most of the other species of flies that cause myiasis
what else can occur with infection of D. hominis or C, homnivorax
secondary bacterial infection
