PHD 6 Flashcards
Host and vector of dengue fever? Is there a diff inincubation time in the host and the vector?
Host–man
Vector– aedes
Incubation period–3-14 days in human host
8-12 days in mosquito vector
What virus family does dengue fever belong to?
Flavivirus. It has four serotypes..DEN-1,2,3,4
Do most people with dengue show signs of the infection?
No..80-90% of people are asymptomatic or have an undifferentiated fever.
Those who are symptomatic hwever have a breakbone fever.–symptoms are mild to severe.,temps from 102-105, bradycardia, headaches, conjunctivitis and retroorital pain. The pt also experiences severe muscle and joint pain.
Describe the rash that is assoc w/dengue fever
It’s present in about 50% of people. It’s a maclar rash that may give rise to petechiae. It starts on the trunk and spreads to the face and the extremities.
What is the transmission cycle of dengue fever?
The mosquito feeds on a host that is viremic—EXTRINSIC INCUBATION PREIOD.
Mosquito refeeds and transmits the virus—INTRINSIC INCUBATION PERIOD.
What is dengue hemorrhagic fever?
Can’t be distinguished from dengue fever. Characterized by hemorrhage and vascular leak. Pts present w/petechiae, epistaxis, gingival bleeding.
Lab findings–thrombocytopenia and increased Hb (Remember that they’re losing plasma,not blood.
What is the tourniquet test?
Inflate bp cuff to a point midway btwn systolic and diastolic for 5 mins.
Positive test:20 or more petechiae per 1 inch squared
What is antibody dependent enhancement?
Process in which strains of the denue virus complexed w/ non-neutralizing Abs can enter a greater propotionof celsof the mononuclear lineage and increase virusproduction. The infected monocytes then release vasoactive mediatiors leading to an inc in vascular permeability and hemorrhagic maifestations that characterize DHF.
Detection of dengue fever?
Early–PCR
Later NS1 antigen detection
Family, host and vector of yellow fever?
Flavivirus, Host is man or primates, Vector is the aedes egypti
Describe the clinical course of yellow fever.
BIPHASIC ILLNESS!
Day 1-3 infection
Fevers, chills, malaise, anorexia, nausea, headache, myalgia and backpain
Day 4–remission, symptoms abate
Day 4-10 (intoxication)
fever, nausea, vomiting (black), anxiety, confusion, jaundice, petechiae, elevated liver enzymes and bilirubin, proteinuria, azotemia
Day 7-10 preterminal
Day 10-convalescent
Pathogenesis of yellow fever? Diagnosis of yellow fever/
Replicates locally in tissues. Spread via blood to liver, spleen and bone marrow and heart.LIVER is mainorgan affected.
IgG and IgM Abs are used in diagnosing the virus
Is there a vaccine for yellow fever?
Yes there is a live attenuated virus, however it can cause a viscerotropic illness in some people.
Which virus causes hantavirus pulmonary syndrome?
Sin nombre virus. It is transmitted by infected rodent urine. Remember that a classic thing to look for on blood smear is immunoblasts.
Diagnosis of hantavirus pulm syndrome?
Serology–IgG and IgM, immunohistochemistry and RT-PCR.
Host of Lassa fever?
Rodents are the host.
Two pearls; Long term sequelae of deafness and responds to ribavarin
Where is the lassa virus found?
Found on the West Coast
In which part of the world is Chikungunya endemic?
Italy!
How is chikungnya diff fr dengue fever?
It usually doesnt have a hemorrhagic component and it presents with joint pain (arthritis) as opposed to muscle pain in dengue.
Similarity; 50% of flks get a rash. Rem however in dengue, you get patches of sparing.
Risk factors for a giardiasis infection?
IgA deficiency and achlorhydia
Symptoms of giardiasis?
Epigastric pain, nausea, diarrhea
Test of choice in most labs for giardiasis?
Stool ELISA
Giardiasis treatment?
Treat w/ metronidazole
How would you diagnose cryptosporidiosis?
Stool O and P, acid fast staining
What three parasites stain acid fast in the stool?
Cryptosporidium, Cyclospora and Cystoisospora
Treatment of cryptosporidisis?
Electrolytes (fluid replacement), nitazoxonide. Boil water as a means of prevention.
Apart from acid fast staining what is another mechanism by which cyclosporias can be diagnosed?
AUV autofluorescence.
How is entamoeba histolytica transmitted?
fecal-oral
Flask shaped ulcers are characterisstic of an infection with this?
Entamoeba histolytica
E. histolytica may also affect the liver. What would you expect the lab values to look like?
Leukocytosis, no eosinophilia and inc alk phos
Scientific name of the pin worm?
Enterobiasis
Descibe the life cycle of the pin worm
Direct life cycle–fecal, oral. The eggs are on the perianal folds, they are then ingested by humans, the larvae hatch in intestines of cecum.
How do you diagnose enterobiasis? Treatment?
Scotch tape test. Treat w/ albendazole
What is the life cycle of trichuriasis?
Direct fecal oral.
How do patients w/ a trichuriasis infection present?
Most patients are asymptomatic, if it is a really bad infection, diarrhea may be present, anemia and CHARACTERISTICALLY anal proplapse
How do you diagnose and treat trichuriasis?
O and P..look for fotball shaped eggs. Treat with albendazole
Life cycle of Ascaris?
Indirect fecal oral. Remember that the eggs first have to mature in the soil. Next it is ingested and the larval stage enters the blood stream—>lungs up the airway and is re swallowed.