Microbiology Vector Borne Diseases

5 Species of Malaria

*Plasmodium falciparum- deadly species, mostly in Africa, the one we'll focus one Plasmodium vivax- Mostly in India Plasmodium ovale- Mostly in South America Plasmodium malariae-forget Plasmodium knowlesi-forget

Dengue Virus Infection

-*almost all are asymptomatic -symptomatics may have fever, rash, myalgia and joint pain "break bone fever". They then can have either Dengue Fever or Dengue Hemorrhagic fever; those with Dengue Hemorrhagic fever can have either no shock or Dengue Shock Syndrome

Rickets Transmission

-*can undergo vertical transmission (mother to child) - 24 hour period to undergo changes to be effective - most active between April-Septmeber

Treatment of Malaria

-Chloroquine the major drug used in malaria plus Primeaquine for Liver Stage. -Chloroquine Resistance- Quinine sulfate plus doxycycline -Pregnant women- use clindamycin -theres also an alternative drug therapy

Prevention of Malaria

-Control the mosquito Vector -Prophylactic antimicrobials malarone- more expensive doxycycline- cheaper mefloquine- take once a week, but it gives you weird dreams.

Name at least 4 factors causing Dengue Increase in the population

-Incr. population growth -Jet travel -lack of vector control -health services poorly organized/funded

Clinical Course of Malaria

-Prepatent period: patient is asymptomatic while parasite multiplies in liver. (Note: this form should not be present in Falciparum) -Paroxysm period: shaking chills, then high fever (<106° F) when infected RBC burst to release new merozoites. Headache, nausea, vomiting, malaise, diarrhea

Rickettsia rickettsii

-obligate intracellular bacteria -gram negative -Energy parasite. Can't make carbon sources or ATP so it feeds it off the host.

Dengue Shock Syndrome

-plasma extravasation (leakage) into extravascular sites-cytokine mediated results in *hypovolemic shock; thrombocytopenia, DIC- more common in second infections

Cerebral Malaria

-worst form of malaria; impaired consciousness; severe anemia; multi organ failure. -Pathogenesis: see syllabus

Pathogenesis of Rickets

1.Organism injected into bloodstream 2. Endocystosed by endothelial cells 3. Escapes from phagosome 4. Replicates in the cytoplasm 5. Utilizes host actin for motility and neighboring cell invasion 6. Allows the bacteria to spread from cell to cell without encountering extracellular environment. Results: -hypovolemic (low blood) shock due to blood leaking out of damaged endothelial cells - Hyponatremia- hormone lowers blood sodium due to hypovolemia -less platelets due to its consumption -results in some but not all cases in a rash from vascular injury

Dengue Life Cycle

A Person Under Rocks Ate Mud, Really? Attachment Penetration Uncoating Replication Assembly Maturation Release

Mosquito that spreads Dengue

Aedes Mosquito. Aedes sounds like Haiti, where I am from (woot) and where the disease is common.

Mosquito Vector

Anopheles Female

What are some vector control strategies of Dengue, and what other disease does it share these strategis with?

Dengue has no antivirals or vaccines. Control mechanisms would be implementing Screens, Nets, the same kind used in Malaria.

Case Symptoms: Fever, Rash, headache and Joint pain with recent travel to Caribbean or South and Central America caused by Virus

Dengue until proven otherwise

Dengue Shock Syndrome is most prevalent when?

During the 2nd infection

Malaria Life Cycle

Falciparum- has no liver stage, no hypozoite stage. Treat blood stage Vivax- can form hipnozoites (hypnosis=sleeping) where the sleeping malaria can be in the liver, so you must treat both liver and blood stages. Ovale- can form hipnozoites (hypnosis=sleeping) where the sleeping malaria can be in the liver, so you must treat both liver and blood stages.

Low Immunity Malaria Areas vs. High Immunity

Low Immunity: Bites by mosquitoes are infrequent so entire population are immunological virgins and both adults and children get disease High Immunity: Sub-Saharan Africa bites are more frequent, so adults are semi- immune. young children and travelers are at risk (no immunity)

Treatment of Liver Stage Malaria

Malaria can be dormant up to a year. Treatment of liver stage done by Primeaquine. Prevents Re-lapse -In G6PD patients, this causes hemolytic anemia

Case Symptoms: Fever, headache, nausea, diarrhea, dizziness, myalgia and fatigue. Traveled to Tropical Areas of the world, places along the equator

Malaria until proven otherwise

How do you get Vector Borne diseases

Must be Exposed to the Vector

Malaria

Obligate intracellular (eukaryotic) Protozoan Parasite. Infects liver cells and RBC's -Asexual and sexual life cycles -Mosquito and Host life cycles

Which vector borne disease(s) resulted in hypovolemic shock?

RMSF(rickets) and Dengue (from Dengue Shock Syndrome)

Treatment of RMSF

Removal of tick mouth parts and Doxycycline

Case Symptoms -Patients with fever, rash, photophobia and headache during April-September -Tick exposure is key -Most common vector borne disease in NC - Caused by bacteria

Rocky Mount Spotted Fever Disease (RMSF) until proven otherwise

Dengue

ssRNA+ virus -member of Flavi viruses which include West Nile and Yellow Fever Virsues -Four Serotypes labeled 1-4.