Nemotods Flashcards
Basic characteristics nematod
bilaterally symetrical pseudoceolomate longitudinal muscles only (sinusoidal movement) dioecious true mouth and anus require warm moist soil for eggs.
Trichuris trichiura
whip worms DH: humans direct life cycle found in tropics because of environment eggs are infective stage transmission due to breakdown in sanitation
T. trichiura pathology, diagnosis, treatment, prevention
dysentary, bloody stool, anemia, rectal prolapse, physical and mental retardation
fecal exam for eggs
abendazole
mass treatment of children regardless of infection status
Trichinella spiralis
cosmopolitan
indirect life cycle
same host is DH and IH
infects humans, pigs, rats, and mammals
T. spiralis life cycle
DH ingests nurse cells with J1
J1 develops to adult in gut
Produces more J1
J1 migrate to muscle tissue go intracellular
Hijack gene expression to feed parasite, becomes nurse cell
DH consumes nurse cell form undercooked meat
T. spiralis domestic cycle
important to human health
pigs and rats
transmission facilitated by human practices of feeding pigs trash/ground up pigs parts
T. spiralis sylvatic cycle
tropical, temperate and arctic hosts
T. spiralis pathology
happens at three stages:
- enteric: nonspecific, misdiagnosed as food poisoning
- migratory: rupture of blood vessels, swelling. death depending on location and intensity.
- muscle: extreme muscle pain, inflammation, death depending on location and intensity
T. spiralis diagnosis and treatment
muscle biopsy
can only be treated during enteric stage. prevention is best. Cook pork all the way through!
Capillaria hepatica
DH: rodents
adults in liver
IMPORTANCE: host must die for transmission
transmitted when (1) mouse dies, rots, eggs exposed to environment and consumed by DH or (2) mouse eaten, digested, eggs released by consumer, exposed to environment and then eaten by rodent.
Dioctophyme renale
DH: mammals
adults in right kidney only
importance: host must stay alive for transmission
Strongyloides stercoralis
tropical parasite
transmitted because of sanitation breakdowns
DH: humans
RH: dogs
parasitic free-living life cycles. Autoinfection also
Treatment: Ivermectin
Diagnosis: fecal smear for J1
S. stercoralis pathology
- penetration site: pain, dermatitis
- migration from heart to lungs to gut
swelling, redness, pnuemonia-like - intestinal once adults establish infection
symptoms are intensity dependent; tissue damage, ulcers
Necatur americanus
Ancylostoma duodenale
DH: humans
cosmopolitan in tropics was in US SE.
eggs passed with feces, J3 penetrate into host
N. americanus and A. duodenale pathology/diagnosis/treatment/prevention
- penetration
- migration
- intestinal: dependent on intensity, species, and host nutritional status. characterized by high blood loss, iron deficiency anemia, protien deficiency
fecal exam for eggs (I think)
Albendazole
education and wearing shoes/using toilets
Ancyostoma caninum
Ancyostoma braziliense
general, pathology, treatment, control
affect cats at dogs in US can cause Creeping Eruptions/Cutaneous Larvae Migration in humans because of wandering worms ALbendazole cream clean up after dogs/cats
Ascaris lumbricoides
Giant Intestinal Worm cosmopolitan globally: largest global spread and most common soil transmitted helmentheis DH: humans spread by fecal contamination of soil infective stage: eggs
A. lumbricoides pathology/diagnosis/treatment
migration (pnuemonia-like, coughing) in gut (intestinal blockage) wandering worms when females searching for males fecal exam for eggs Albendazole
hookworms
N. americanus
A. duodenale
A. caninum
A. braziliense
Toxocara canis
Toxocara cali
Brayisascaris procyonis
dogs cats racoons cause visceral larva migrans in human when human ingests eggs. J3 hatches and wanders through tissue and can end up anywhere. Tx: Albendazole but difficult
Enterobius vermicularis
pin worm
cosmopolitan in temperate areas
DH: humans
monoxenous; literal hand-to-mouth transmission
E. vermicularis pathology/treatment/Diagnosis
not much
albendazole and then heat house up to kill eggs
Scotch Tape Test for eggs or just look for worms in butt
risk factors/control/clinical manifestation/diagnosis of soil transmitted helminthes
- poor sanitation of human feces leading to contamination of soil, food, and water
- sanitation and hygiene
- adverse effects of parasite in intestine (malnutrition diarrhea) and mental and physical retardation
- eggs in feces except for Strongyles
Human Lymphatic Filariasis/Elephantiatis
caused by Wuchererua bancrofti, Brugia malayi, and Brugia timori
DH: humans
IH: mosquitoes (Culex pipens in urban areas and Anopheles spp. in rural areas)
J3 is human infective stage
Periodicity
microfilariae (infective stage to IH) circulates in blood only when mosquito vectors is active and is in tissue otherwise.
Pathology, diagnosis, treatment HLF/Elephantiatis
lymphanema-massive lymph swolling, accumulate of lymph fluids in lower extremities
Hydrococle-swollen scrotum
secondary infection because of cracks/hardening skin
blood smear for microfilaria or use Card (?) test for antigens in blood
DEC in areas without river blindness, Ivermectin in river blindness endemic areas
xenomonitoring
using PCR to detect filarial worm DNA in pools of wild caught mosquitos to determine if parasite is still endemic in an area
cannot detect if mosquito is capable of transmitting disease
Lymphatic Filariasis in Egypt
W. bancrofti endemic in delta area, around Aswam high Dam
vector: Culex pipiens pipiens
dam increased prevalence because of standing water
only hydrococle no lymphanema
Lymphatic Filariasis in Papua New Guinea
all forms of lymphatic filariasis present
1 million infected, 4 million at risk with W. bancrofti
10-92% prevalence
endemic with malaria
Onchocerca volvulus
causes River Blindness
endemic in West Africa and Central/South America
DH: humans
IH: Black fly (F. simulidae and G. simulian spp.)
O. volvulus pathology/diagnosis/treatment
adults: nodules and hanging groin
microfilariae: dermatitis (leopard skin, itching becuase of bacteria hyperparasitism) and blindness
skin snip DO NOT CONTAMINATE WITH BLOOD
nodulectomy to remove adults
mass drug administration with Ivermectin for 16 years
Loa loa
African Eye Worm DH: humans IH: deer dly (genus Chrysops, family Tabanidae) J3 infective stage can see worm migrating under skin
L. loa pathology/diagnosis/treatment
Calabar swelling when worm stops moving
surgery
blood smear for mf
using DEC to treat W. bancrofti not possible in L. loa endemic areas
Dirofilaria immitis
Dog heart worm
DH: dogs
IH: Aedes spp. (J3 develop in Malpigian Tubulus)
D. immitis pathology/diagnosis/Treatment
exercise intolerance, cough, death
antigen detection test
surgery but dangerous so prevention with Ivermectin
Dracunculus medinensis
Guinea Worm/Fiery Serpent largest nematode (80cm) was cosmopolitan in African and Asia. DH: humans IH: copepod Humans infected by drinking water with J3 infected copepods
D. medinensis pathology/diagnosis/treatment/prevention
worm bursting out of leg
none except seeing worm come out of leg
surgery but complex. DO NOT BREAK WORM. so roll worm out on stick until fully emerged.
filtering water with cheesecloth to remove copepods and education programs
Phylum Ancanthocephela
parasitize all classes of vertebrates (not humans)
“thorny headed worms”
two body parts only
IH: arthropod
Phylum Arthropoda
“jointed legged animals”
Insecta and Arachnida
Order Anoplura
in phylum Arthropoda lice! Phthirus pubis: pubic lice Pediculus humanus capitis: head lice Pediculus humanus humanus: body lice (do not adhere to skin, vector of human pathogens)
- adults lay eggs (nits)
- nyphms
repeat
P. h. humanus
vector for bacteria that cause Trench Fever, Relapsing Fever, and Epidemic Typhus
associated with poverty
Vagabond’s disease
Treatment: DDT/insecticide and throw away or wash clothes
Cimex lectularis
bed bugs
incomplete metamorphosis
pathology: little to large reaction of red itchy bites
Tx: treat whole house with insecticide (RESISTANCE!) or throw away mattress
Flea Order
Siphonoptera
Ctenophalides
cat/dog flea in US full metamorphosis (adult, egg, larvae, pupae)
Yersinia pestis
bacteria that causes the plague
transmitted by Xenopsylla cheopis (oriental rat flea)
urban cycle tranmission: Rattus rattus eats infected flea
Y. pestis pathology and treatment and diagnosis
- Bubonic plague: lymph node swelling
- Septicemic plague: in blood
- Pneumonic plague: eliminates need for vector transmission. human-human aerosols. 100% mortality almost
antibiotics but Y. pestis has potential to become resistant. treat during Bubonic stage if possible.
blood smear and stain for bacteria
alternative transmission Y. pestis
biting/eating fleas
Tick taxonomy
Arthropoda
Arachnida
Arcari
Ixodidae and Argasidae
Tick body parts
- capitulum=head
has hypostome, chelicerae, palps for feeding - Idiosoma=body
Tick life cycle
male and female adults blood feed lay eggs larva (6 legs) nymph (8 legs) Adult ***All stage must blood feed to contine development**
Reason for Diversity of pathogens spread by ticks
- large population size (no predators, environmentally resistent)
- blood feeding habits (slow and painless, huge meals)
- longevity (can live for years)
- transovarial transmission
Two ways ticks find hosts
- questing: find a vantage point and wait for host to touch it
- Hunting/Ambushing: actively search for host
example: Lone Star Tick
Tick Pathology
1. anemia 2 dermatosis if improper removal 3. Otoariasis if tick in ear canal 4. Tick paralysis caused by saliva (Dermacentor spp.) 5. infection
Borrelia burgdorferi
lyme disease
transmitted by deer tick Ixodes scapularis
hosts: white-footed mouse, white-tailed deer, humans, ticks
pathology B. burgdorferi
stage I: Bull’s eye rash (60% of people only), non-specific symptoms
stage II: secondary rashes, joint and muscle pain
stage III: arthritis, changes in behavior, central nervous system involvement
Treatment/diagnosis/prevention B. burgdorferi
antibiotics; easier the earlier it is caught
1st: serology but many false positives
2nd: Elisa/western blot for Borrelia antigens
long pants and socks deal or wear deet and do partner tick check.
what makes a good vector
- feed on correct host
- complete development supported by environment
- transmission by natural feeding
- size of population
- habitat requirements met
- flight range suffiecient
Aedes
floodwater mosquitoes
single egg that must dry out
Culex
house mosquitoes and others
egg raft
Anopheles
dappled-winged mosquitoes
single egg with floats
Arbovirus
arthropod borne viruses
many are zoonitic
Why emergence of new diseases?
- human behaviors (factory farming, living in cities, destroying forests)
- speed of global travel increased
- genetic changes in pathogen
- immunocomprimized hosts
Chickengunya virus
recently expanded range from Africa to Asia and Americas
causes acute and chronic arthritis
very high mutation rate
no treatment or vaccine
potentially Wolbacia-infected mosquitoes like trying with Dengue fever
Strongyloidiasis
Strongyloides stercoralis
Ascarids
Ascaris lumbricoides Ascaris suum Toxocara canis Toxocara cati Balisascaris procyonus
Soil transmitted helminths
whip worms
strongyloidiasis
hook worms
ascarids
filarial worms
Brugia malayi Brugia timori Wuchereria bancrofti Onchocerca volulus Dirofilaria immitis Loa loa
other nematodes
Dioctophyme renale Capillaria hepatica Trichinella spiralis Enterobius vermicularis Dracunculus medinesis
Nematodes
filarial worms
other nematodes
Anoplura
Pediculus humanus humanus
Pediculus humanus capitus
Pthirus pubis
Acari
ixodes scapularis
Dermacentor spp.
Siphonaptera
Xenopsylla cheopis
Cimicidae
Cimex lectularius
Arthropods
Anoplura
Acari
Siphonaptera
Cimicidae
Bacteria
Borrelia burgdoferi
Yersinia pestis
Vectors
Mosquitoes: Culex pipens, Aedes spp., Anopheles spp.
Deer flies: Tabanidae
Black flies: Simulidae and Simulian spp.
