Microbial Infections of the Blood and Blood Cells Flashcards
(75 cards)
1
Q
What 2 categories can Parasites be divided into?
A
Protozoa and Metazoa
2
Q
What are protozoa?
A
Single celled eukaryotes
(Rhizopods, ciliates, flagellates, sporozoa)
3
Q
What are Metazoa?
A
Multi celled eukaryotes
(Helminthes, flatworms, roundworms)
4
Q
What parasites cause malaria and Babesiosis?
A
Sporozoa
5
Q
How do sporozoa resproduce
A
Asexual or sexual
6
Q
Malaria takes place in
A
Humans and mosquitos
7
Q
Babesiosis takes place in
A
Humans and ticks
8
Q
What si malaria?
A
Tropical and subtropical, mosquito transmitted life threatening disease that manifests as intense cyclic fever, with chills and sweating
9
Q
What are etiological agents for malaria?
A
The disease is induced by infection with protozoan parasites, Plasmodium
10
Q
What are the most important species of malaria?
A
- Plasmodium falciparum
- Plasmodium vivax
11
Q
Where si plasmodium vivax found?
A
Asia
12
Q
Where is plasmodium falciparum found?
A
Worldwide in tropical and subtropical areas and Africa
13
Q
How is malaria spread?
A
Anopheles mosquito and blood transfusion
14
Q
Plasmodium infects 2 organs in humans which include what?
A
Liver and RBC
15
Q
Describe transmission of malaria
A
- Anopheles species
- Female mosquito probes for a blood meal
- Deposit parasites through their salivary glands
- Parasites traverse the capillary wall and enter the blood stream
- Migrating to the liver
16
Q
Malaria: Describe Asexual Liver stage
A
- Occurs in vertebrates
- Parasites invade hepatocytes
- Asexual rep occurs
- Release thousands of parasites to infect RBCs
- Liver- stage of life cycle is not associated with notable disease in malaria. It allows the parasite to multiply and increases in number
17
Q
Malaria: Asexual Erythrocytic cycle- Once burst from hepatocytes, they invade
A
RBCs, using surface molecules (ex: Duffy antigen fro entry)
18
Q
Malaria: Asexual Erythrocytic cycle- how do they multiply in RBC?
A
Using amino acids obtained from digesting hemoglobin
19
Q
What phase of asexual repr is associated with most of the pathology in malaria?
A
The eythrocytic cycle
20
Q
Describe sexual rep in Anopheles mosquito
A
- Small prop of parasite in infected RBC differentiate into transmissible male and female gametocytes in the mosquito gut
- Fust to form zygote
- Sygote develops into a parasite- filled oocyst
- When oocyst bursts, parasite move to the mosquito’s salivary glands, ready fro introduction into the next host
21
Q
Describe pathogenesis of malaria
A
- Cytoadherence: rosetting and endothelial cytoadherence
- Disruption of blood supply to various organs
- lysis of RBCs
- Tissue hypoxia
22
Q
How does malaria present clinically?
A
- Symptoms appear few weeks after being bitten by mosquito
- Parasites can lay dormant for months to years
- Disease can manifest as a heterogenous set of symptoms, varying from person to person
- Vast majority of cases are mild
- Severe cases can be incapacitating and fatal
23
Q
How is uncomplicated malaria characterized?
A
- Shaking chills
- high fever
- Profuse sweating
- Cyclic pattern
- Other symptoms: headache, vomiting, diarrhea
24
Q
What are oral manifestations of malaria?
A
- Malaria induced anemia causes oral conditions
- Oral dryness; tongue sticking to palate, thirst
- Difficulty chewing, swallowing, speech
- Impaired taste
- Burning and soreness of mucosa and tongue
25
Fever in malaria is generated by what?
Innate immune response tot he lysed RBC; it is cyclic because the lysis occurs synchromously at intervals
26
Severe malarial anemia is associated with
Chronic and repeated infections of malaria due to hemolysis.
Hemoglobin in urine
27
Acute repiratory distress synrome from severe malaria
Inflammation and accumulation of fluid. Inhibits oxygen exchange. Difficult to breathe
28
Organ failure from severe malaria
Low BP can cause kidney or liver to fail, cardiovascular collapse or spleen to rupture
29
Cerebral malaria is mostly seen in
Children under 5 years
30
Describe cerebral malaria
Infected RBCs autoagglutinate, forming rosettes that accumulate and obstruct microvasculature in the brain inflammation leads to immune mediated destruction, disruption of BBB, swelling of brain
31
Describe renal insufficiency and metabolic acidosis from malaria
Heavy lysis may cause excessive acidity in the blood and tissue fluids, pH of the blood lowered
32
What are oral manifestations of malaria?
- Dry mouth from fever, acidosis and anorexia
- oral lesions
- Antimalaria medications (chloroquine) has adverse effect of oral ulceration
33
Malaria: Humans develop metaological changes to reduce
Plasmodium growth and survival
34
Malaria: Infected hepatocytes and erythrocytes have diminishing expression of
HLA-DR on dendritic cells
35
Describe sickle cell trait
- Strucutrally abnormal Hb
- Heterozygotes for the abnormal hemoglobin gene HbS; valine instead of glutamic acid at the 6th position in the beta chain of the hemoglobin gene
36
Describe G6PD deficiency in terms of malaria
Increase oxidative stress on the parasites and the host RBC
37
Describe duffy blood group
African pop are negative for the Duffy blood group and have RBCs that are resistant to infection by P. vivax
38
How does P. falciparum look histologically?
Banana shaped gametocytes and ring from trophozoites
39
How is malaria diagnosed?
- Detail of travel
- Degree of anemia
- macroscopic exam of blood
- Isolation of agents, sero diagnosis of antigens in serum, urine and stool
- Nuclei-acid (PCR) based assays
40
What was a widely effective tx for malaria that grew resistance?
Chlorquine
41
What is Artemisinin?
Drug developed during Vietnam was- now the worlds frontline tx for malaria
42
How is malaria prevented outdoors?
Fogging or area spraying
- Target larval stages of mosquito
- effectiveness generally weak
43
How is malaria prevented indoors?
- Indoor residual spraying
- Long lasting insecticidal nets
- target the mosquito
44
What is a vaccine for malaria?
R21/Matrix M
45
What does the R21/Matrix M vaccine consitst of?
Virus like particles witht he repeat region of the circumsporozoite protein fused to the hepatitis B surface antigen mixed with the Matrix M adjuvant particles
46
For travelers, highest risk of malaria is
- Immigrants living in non-endemic countries who return to their countries of origin to visit friends and relatives
- pregnant people approximately half of all of the cases
47
What should travelers do for malaria?
Take malaria prophylaxis and buy these drugs in their country to avoid counterfeit antimalarial drugs
48
Babesiosis is seasonal and mainly peaks during what months?
Warm months
49
Babesiosis is most common in what areas?
Northeast and upper midwest- NE, NY, NJ
50
Babesiosis: Sexual reproduction occurs in
the tick, Ixodes Scapularis (poppy seed size- so often ppl dont recall a bite)
51
Babesiosis: Asexual rep occurs in what?
White footed mice, infecting their RBC
52
Describe sexual rep of basediosis
- Parasites enter RBC and undergo asexual and sexual rep
- replicate and infect other RBC
- Parasites produce gametes
- gametes get ingested by ticks
53
What is the clinical presentation of basediosis?
Nonspecific flu like symtpoms
- Fever, chills, sweats, headache, body aches, loss of appetite, nausea, fatigue
May last several weeks
54
Severe blasidosis occurs particularly in people who
Dont have a spleen, have a weak immune system or are elderly
55
What are clinical symptoms of severe blasidiosis?
- Low and unstable BP
- Severe hemolytic anemia
- Disseminated intravascular coagulation, which can lead to blood clots and bleeding
- Malfunction of vital organs
- Death
56
How is blasidiosis diagnosed?
- Travel history
- Microscopic exam of blood smeal (Maltese cross shaped)
57
What are treatments for blasidiosis?
Atovaquone & Azithromycin
Clindamycin & Quinine
58
Symptoms of malaria manifest when
RBCs are infected
59
What is sepsis?
Life threateming medical emergency that occurs when body's immune system overreacts to an infection
60
What can cause sepsis?
- Bactermia (most common), Fungaemia, parasitemia and viremia
61
What are general symtoms of sepsis?
Fever, difficulty breathing, low BP, fast HR and mental confusion
62
Sepsis can affect anyone- who is at high risk?
- Weakened immune system
- Older than 65, newborns, infants, pregnant people
- Underlying comorbidities (diabetes, obesity, cancer, kidney disease)
- In hospital for other reasons
- Concurrent injuries such as large burns or wounds
- With catheters, IVs or breathing tubes
63
How can sepsis occur with dental infections?
Neglected tooth can cause bacteria to move into bloodstream and travel. G- flora colonizing the throat of hospitalized patients can progress to sepsis
64
What are the stages of sepsis?
1. SIRS
2. Sepsis
3. Severe sepsis
4. Septic shock
65
Describe SIRS stage of sepsis
Systemic inflam response syndrome (cytokine elevated).
- Hypothermia, tachycardia, tachypnoea, change in WBC count
66
Describe the sepsis stage of sepsis
Microbial infection determine as tha cause of SIRS
67
Describe the severe sepsis stage of sepsis
Acute organ dysfunction and mental confusion
68
Describe the septic shock stage of sepsis
Persisting extreme hypotension requring vasopressors (NE) to maintain arterial pressure
69
G- bacteria have the PAMP molecule
LPS on its outer surface
70
G+ have
Peptidoglycan as the PAMP
71
The binding of what triggers the immune response in sepsis?
PAMPS to Pattern recognition receptors
72
What is an example of PRR?
TLRs
73
When certain TLRs are triggered by a microbial antigen, there is a signal transduction pathway that leads to
Activation of the transcription factor nuclear factor kappa B (NF-kB)
74
NF-KB engages a promoter in the cellular DNA and allows
Transcription of the panel of pro-inflammatory cytokines that characterize sepsis
75
How is sepsis tx and managed?
- Ensuring hemodynamic stability
- Primary source control may involve surgical intervention
- Collecting culture specimen
- Give broad spec antibiotics
- Glucocorticoids for inflam
- Control blood glucose
