L21: Fleas, Bugs and Flies Flashcards
What are fleas
small insects that feed on animal and human blood
many species, most parasitic on mammals (rats) and birds
*prefer animals but will bite people
*reelvant cause vector of pathogens they transmit through feeding hosts or fecal contamination to open wound
List common flea species and assocated hosts
4 main affected species:
1. Cat flea – Ctenocephalides felis (despite the name, it is common on dogs, other pets and domestic animals)
2. Dog flea – Ctenocephalides canis
3. Human flea – Pulex irritans
4. Oriental rat flea – Xenopsylla cheopis
Discuss the microbes tranmitted by flease
Bacteria
▪ Ctenocephalides are vectors of Rickettisa cause rickettsial disease and Bartonella henselae causing cat scratc disease
▪ Xenopsylla cheopis transmitting T.petisi which causes plague and flea bourne murine thypus
Protozoa
▪ Xenopsylla cheopsis intermediate hosts for al rodent-borne trypanosomes
Helminths
▪Ctenocephalides intermediate hosts for cestode Hymenolepis and Dipylidium
P.irritians not vector but cause allergic reaction cause of salivary proteins
heavy infections lead to
anemia especially in young animals
Distinctive Features of Important Flea Species
Cat
*3-4
*sloping elongated head
*has ctendia comb strcutures
*genal and pronotal comb almost same length
Dog
*3-4
*rounded head wit ctednia
*genal comb is shorter than protonal
P.irritans
*1-4
*no ctednia in head
*front of head it sounded no meral rod
Xeno
*1-4
*head no ctednia
*front of head is rounded
meral rod present
*WORLDWIDE
Describe flea morphology
*2-6 mm and very small head
*bilaterly compressed to allow easy movement through hair and feather
*mouthparts for piercing skin and sucking blood
*light brown, no wings, enlarged hind limbs to jump 100x their body length
Flease life cycle
adult fleas
eggs
larval stage
pupa stage
adult fleas
5 key flea treatment
sanitation where they breed and wash bedding, vacum
pet treatment for every pet and wash then then comp then, use soap with insecticide to kill adults
home treatment same time as pet to disrupt flea cycle
follow up because life cycle is complex some may be reisitanct to insectides so its an ongoing process
use antiitching cream like antihistamines or hydrocortisone
Prevention and control of flease
limit pet going to flea aras
use repellent, clean up, lower humidity, lowering temps
keep rodents and wild animals away
Which bugs are medically important and 2 closely related that infect humans
2 familieis of Hemiptera
1. Reduviidae: Kissing bugs (also called Assassin bugs – winged)
2. Cimicidae: Bed bugs (wingless. The focus of this lecture)
Two closely related species of bed bugs that commonly infest humans are:
1. Cimex lectularius – the common bed bug, cosmopolitan in distribution
2. Cimex hemipterus – the Indian bed bug, restricted to the tropics and sub-tropics
Bugs
found where humans are, remain hidden, and exit hiding spot when its dark or dim to feed on hosts
adult and nympals stages of Cimex must take warm blooded meals, human becomes incidental hosts of the bat/birds cimex
all bed bugs are incomplete metamorphic
The Life Cycle of Bed Bugs
eggs, nymph, adult
The Life Cycle of Bed Bugs
Traumatic insemination: Also known as hypodermic insemination, is a forceful mating tactic that involves a male bed bug inserting its genitalia into the non-genital tissue of a female bedbug by stabbing through the exoskeleton. Sperm is released into the female’s hemolymph and migrates through the circulation to the ovaries, resulting in fertilization
Clinical Presentation & Diagnosis of Bed Bug Infestations and treatment
Clinical
*bites cause of allergic reaction salivary they have anticoagulatans and anethetics
*but they are ineffective vectors of disease
Diagnosis
*often misdiagnosed but you know from breakfast lunch and dinner pattern
*see adults and lymphs n ear when bitten
*heavily infected smell from salivary bed bug order
Treatment
*self limiting
only need antisepic location to prevent secondary
can use antihistamines to manage itching
use insecticide in homes but professional pest control is needed
better to prevent it instead od treating it
What are flies, wings, order, types
Dipter true fly order
winged with 2 pairs attached to thoraz
complete metamorphosis and classified by biting (blood sucking) or non biting
Types of flies and pathogencicy with examples
Biting: are vectors and spread sandflies (leishmaniasis), blackflies
(onchocerciasis), mosquitos (malaria, filariasis) and tsetse flies (sleeping sickness)
Non biting: flies deposit eggs, from which larvae emerge and feed on
host tissues and exudates
=>These larvae are pathogenic during development and live within the tissue
of the infected host – they are obligate parasites and cause a condition
known as myiasis
What is flu myiasis
parasitic infection where larvae are bured in host tissues usually
*they borrow in healthy or nectoric with mandibular oooks and protelytic enxzymes
*if they belong to genera that parasit animals they may also do humans
*can be obligatory, faculative or accidental (in humans
Name fly genera that cause myiaiss
Dermatobia hominis – human bot fly (A common species in Canada)
✓ Cochliomyia hominivorax – screwworm fly (New World)
✓ Chrysomya bezziana – screwworm fly (Old World)
✓ Cordylobia anthropophaga – tumbu fly
Give example of facultative myais causer
g. Musca domestica and Lucilia illustris
Life Cycle of Dermatobia hominis – human bot fly
adult, eff, larvae, pupate, adults
Life Cycle of Other Myiasis-Causing Flies
screwwom flies
Gravid female screwworm flies lay
eggs on (or around the edges of) a
superficial wound or mucous
membranes of a body orifice. Eggs
hatch into larvae that burrow into
the wound or flesh of the orifice.
Larvae feed on living tissue
CAUSES WOUND MYIASIS they can leave subdermal tissue and go through body tissue
house flies
Gravid female house flies lay eggs
on moist, decaying material
(garbage, feces). Larvae feed on
decaying organic material. When
larvae invade host tissues, they can
cause myiasis, feeding on decaying
and necrotic tissue. This is rare
tubmu flies
Gravid female tumbu flies lay eggs
on soil contaminated with urine or
feces, and damp clothes. Emerging
larvae can survive for up to 2 weeks
in the soil. They attach to any host
they encounter and penetrate the
skin. Larvae feed on living tissue.
Flies: Clinical Presentation of Myiasis
its classified by site
cutanouse: furuncular, migratory, wound
ocular:ophthalomyiasis
nasopharyngeal, aureal, genitourinary, intestinal, cerebral, oral
can get bad, kill livestock and cause secondary infections
How to treat myiasis
phyical removal of larvae if bad then do surgery if the larvae has migrated
no approved treamtn
antibodies for secondary exposure
AT THE END OF THE DAY JUST PREVENT IT
how to remove larva from myiasis
punch biopsy with blade to frm a whole where its ejected
then u extracted it and it heels
