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140 Cards in this Set
- Front
- Back
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What are some antropod-transmitted diseases? |
Rickettsial disease lyme disease malaria west nile virus plague |
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What are some animal-transmitted diseases? |
Rabies Hantavirus |
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What are some soilborne diseases? |
Pathogenic fungi Tetanus |
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Define antropod-transmitted disease |
Spread from host to host by the bite of an insect |
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Define Rickettsia |
small bacteria, intracellular parasites in vertebrate |
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What is Rickettsia associated with? |
blood-sucking anthropods at some point in their life cycle (fleas, lice, or ticks) |
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Rickettsia is closely related to _____ |
mitochondria |
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What are the three groups of Rickettsia? |
typhus group, spotted fever group, ehrlichiosis group |
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What does the typhus group of Rickettsia cause? |
causes typhus |
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How is typhus transmitted? |
from human to human by common louse |
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There were typhus epidemics during wartime. (T/F) |
True |
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During what wars was typhus an epidemic? |
Killed 3 million people during WWI Killed more military than combat |
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How do typhus infections occur? |
when puncture from louse bite becomes contaminated with louse feces |
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What did Charles Nicolle receive a Nobel for? |
Received the 1928 Nobel Prize in Medicine for his identification of lice as the transmitter of epidemic typhus |
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What are the symptoms of Typhus? |
Fever, headache, weakness, followed by rash that spreads everywhere except face, palms and soles |
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What does typhus damage in the body? |
Damage to CNS, kidneys, lungs, heart |
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What is the mortality rate of typhus? |
Mortality rate of 6-30% |
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How is Typhus treated? |
Treated with teracycline and chloramphenicol |
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What is Lyme disease caused by? |
Borrelia burgdorferi |
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How is spirochete spread? |
Spread primarily by the bite of a deer tick |
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What are the main mammalian reservoirs for B. burgdorferi in Northeast? |
Deer and the white footed mouse |
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Lyme disease is found all over the U.S. (T/F) |
True |
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What is the lyme disease reservoir in the western U.S.? |
Wood rate Spread by bite of tick |
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The Centers for Disease Control and Prevention reports an estimated ________ cases of Lyme disease each year to state health departments |
300,000 |
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There are similar disease to lyme disease found in _____ and ____- |
Europe Asia |
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What are the Europe/Asia version of lyme disease caused by? |
Caused by similar species of Borrelia |
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Each are has own _____ reservoirs and ____ vectors for lyme disease |
rodent tick |
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What are the symptoms during primary infection of lyme disease |
headache, backache, chills, fatigue |
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In lyme disease _____ of cases develop _____ migrans at site of tick bite |
75% erythema |
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What is the typical rash for lyme disease |
spreading bulls eye rash - clears in center |
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How do you treat lyme disease |
treatable with tetracycline or penicillin at this stage |
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What happens if lyme disease is untreated? |
may progress to the chronic stage |
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Describe chronic stage lyme disease |
Arthritis develops in 40-60% of cases Neurological involvement in 15-20% of cases Palsy, weakness of limbs, facial ticks Cardiac damage occurs in 8% of cases |
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What does chronic stage lyme disease require? |
requires antibiotics such as ceftriaxone that can cross the blood-brain barrier |
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Why is diagnosis difficult for lyme disease? |
antibodies don't appear for 4-6 week following infection |
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Lyme disease antibodies are _____ for years - may not indicate active infection |
persist |
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Lyme disease culture is _____ |
difficult |
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How can lyme disease be prevented? |
By wearing protective clothing and insect repellent |
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What is the lyme disease vaccine used for? |
Vaccine used to be available for people at risk - now not recommended |
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What are the 4 species of protozoa plasmodium that causes malaria? |
P. vivax, P. ovale, P. malariae, and P. falciparum |
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How is malaria spread? |
spread by female mosquitos from the genus Anopheles |
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Where is malaria predominantly found? |
tropics and subtropics |
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malaria development (picture) |
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How many stages of life does Plasmodium have? |
3 |
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What are the 3 stages of life for plasmodium? |
Exoerythrocytic stage Erythrocytic stage Sporogonic stage |
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Define exoerythroxytic stage |
Outside the red blood cell |
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What happens during the Exoerythrocytic stage? |
Mosquito injects sporozoites, travel to the liver Produce schizonts in the liver cells After 6 -15 days, merozoites rupture and enter the blood Hypnozoites - dormant and reactive later causing disease again |
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Define Erythrocytic stage |
inside the blood cell |
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What happens during the Erythrocytic stage |
Merozoites enter blood cell - become trophozoites Phagocytize hemoglobin Form schizonts - produce merozoites Merozoites released and infect new RBCs Some merozoites become male and female gametocytes |
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Define Sporogonic stage |
Begins when a mosquito ingests an RBC with gametocytes |
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Describe the Sporogonic stage |
Gametocytes become gametes in the mosquito's gut Fertilize and become an oocyst 10-20 days later oocyst releases sporozoites Mosquito can infect a new host |
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How is malaria characterized? |
Characterized by cycles of high fever followed by chills |
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What is the treatment for malaria? |
chloroquine - kills parasites in blood cells. Primaquine - kills sporozoites, merozoites, and gametes outside the cells |
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There are usually _____ with malaria treatment - small number remain dormant in liver |
relapses |
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many strains of malaria have developed _____ to drugs |
resistance |
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What is the most effective way to control malaria? |
To break the life cycle by eliminating the mosquito Drain swamps and other breading areas |
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Explain attempts at controlling malaria |
In 1933 in southern US drained 544,000 acres of mosquito breading area. Sprayed millions of gallons of oil on swamps In 1946 established malaria eradication program in south. Sprayed DDT |
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How are some people resistant to malaria? |
Parts of Africa people who produce hemoglobin S - a single amino acid change from hemoglobin A -Binds O2 less efficiently -Causes RBC to become curved -Homozygotes - sickle cell anemia -Heterozygotes - sickle cell trait -Growth of P. falciparum causes sickle cell shape - Sickle cell shape allows K+ to flow out of cell - inhibits P. falciparum |
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Define sickle trait |
provides a survival advantage in regions where malaria is endemic. People (and particularly children) infected with P. falciparum are more likely to survive the acute illness if they have sickle cell trait |
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Describe the characteristics of sickle cells? |
Are stiff and sticky. They tend to block blood flow in the blood vessels of the limbs and organs. Blocked blood flow can cause pain, serious infections, and organ damage |
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West Nile Virus is a membrane of the ______ groups |
flavivirus |
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Describe the flavivirus groups |
Symmetrical, enveloped icosahedral capsid Positive, single stranded RNA genome |
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How is West Nile spread? |
Spread by bite of a mosquito |
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When was West Nile first identified ? |
Uganda in 1937 Spread to Egypt and Israel by 1950s |
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When were the first cases of west nile seen in the US |
1999 in Northeast |
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West Nile is primarily a disease of _____ |
birds |
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What happens when a bird is infected with West Nile? |
Infected birds either die or become immune |
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How does West Nile Disease spread? |
by the mosquitos to new areas |
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Describe the connection between West Nile and mosquitos |
Moving west in the US Symptoms often mild (fever, headache, aches) but can occasionally progress to West Nile encephalitis |
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Life cycle of West Nile Virus (picture) |
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_____ of infected people (West Nile Virus) develop West Nile _____ |
20% fever |
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Describe West Nile Fever |
Headache, nausea, myalgia, rash, lymphadenopathy, malaise 2-3% mortality rate |
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Less than ____ develop West Nile _____ or _____ when infected with West Nile Virus |
encephalitis meningitis |
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When does West Nile encephalities or meningitis mainly occur? |
in adults over 50 |
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Plague killed between _____ of the population of Europe in the Middle Ages. |
25-33% |
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What is the Plague caused by? |
Yersinia pestis - Gram (-) bacteria |
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What is Plague a disease of rodents |
rats are the primary reservoir |
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How is Plague spread? |
Spread by fleas - ingest Y. pestis when feeding on an infected animal than transfer to new animal when feed again |
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Life cycle of plague (picture) |
Plague |
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Plague, once infected, travels where? |
to lymph nodes - causes swollen areas called buboes - bubonic plague |
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What does the plague capsule prevent? |
Phagocytosis - escape the immune system |
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Plague will eventually enter the bloodstream causes ______ |
septicemia |
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Why is Plague also called Black Death? |
Multiple hemorrhages under the skin - black splotches |
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How long does it take to die of plague? |
3-5 days |
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When does Pneumonic plague occur? |
When cells are inhaled directly into lungs |
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When someone has Pneumonic plague how long do they survive? |
People rarely survive more than 2 days |
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Pneumonic plague is highly ______ and can spread rapidly |
contagious |
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In Septicemic plague the bacteria rapidly spread through the ______ |
bloodstream |
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How does death occur in Septicemic plague? |
Death occurs very quickly - even before it can be diagnosed |
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Why might Gerbils now replace rats as main cause of Black Death? |
We show that wherever there were good conditions for gerbils and fleas in central Asia, some years later the bacteria shows up in harbour cities in Europe and then spreads across the continent |
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Can plague be treated? |
If rapidly diagnosed |
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What is Plague treated with? |
Antibiotics |
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What is the mortality rate of plague? |
Mortality 1-5% if treatment begins early enough |
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Plague is a _____ disease today. 97 cases since 1990 in US. |
Rare |
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How many cases of plague worldwide? |
1500 |
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What caused the black death? |
Recent evidence confirms that Y. pestis caused the black death, but more than one strain involved |
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Define animal-transmitted diseases |
Animal disease transmissible to humans called zoonoses |
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What is the natural host of a animal-transmitted disease? |
Natural host is a vertebrate other than humans |
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Wild animals are _____ for animal-transmitted diseases |
reservoirs |
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How is Animal-transmitted diseases transmissioned? |
by contact, aerosols, or bites |
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What is Rabies caused by? |
Caused by the rabies virus, member of the Rhabdovirus family |
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Describe Rabies genome |
Negative-sense single-stranded RNA |
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How many people die each year worldwide? |
55,000 |
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How many people are treated for rabies each year? |
1 million |
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What are the reservoirs for rabies? |
Wild animals major reservoir - raccoons, skunks, coyotes, foxes, and bats |
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What do the rabies virus infect? |
cells of central nervous system in most warm-blooded animals |
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Where does the rabies virus present itself? |
in saliva of infected animal |
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How does rabies enter the body? |
by bite wound Multiples at site of bite, then travels to CNS |
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Rabies virus proliferates in _____ |
brain |
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What are symptoms of rabies |
fever, excitation, pupil dilation, excessive salivation, anxiety |
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How does someone die by rabies? |
Death by respiratory paralysis |
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Rabies treat exposed humans with rabies immunoglobulin and immunization with ______ rabies virus |
inactivated |
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What is Rabies treatment effective |
Long incubation time makes treatment effective |
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We vaccinate all domestic animals for rabies (T/F) |
True |
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The Rabies coat protein expressed in ______/_____ |
vaccinia/virus |
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When was there a Hantavirus outbreak? |
1993 hantavirus outbreak in US killed 32 of 53 infected people |
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Hantavirus is a member of the _____ family |
Bunyaviridae |
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Describe the Dunyaviridae family |
Enveloped negative-sense single stranded RNA viruses |
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What are the symptoms of Hantavirus? |
Symptoms include fever and pulmonary capillary leakage |
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Death occurs in _____ of cases with Hantavirus |
50% |
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What do a lot of people die of Hantavirus? |
Due to shock and cardiac complications due to pulmonary edema |
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Is there treatment for Hantavirus? |
No treatment or vaccine |
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How can you reduce exposure to hantavirus? |
eliminating rodents |
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Talk about the 2012 outbreak in Yosemite |
Symptoms included "a simple cold, a sudden fever - than trouble breathing and an immediate downhill course." |
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The most systemic _____ infections are soilborne diseases |
fungal |
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What are the most common soilborne disease in the US |
Histoplasosis and coccidiodomycosis are most common in the US |
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How do people get soilborne diseases |
Become infected by breathing airborne spores |
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Tetanus is caused by ______ bacteria |
soilborne |
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What is Tetanus caused by? |
Clostridium tetani |
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Describe Clostridium tetani |
Gram (+), anaerobic, spore-forming rod |
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Where does Clostridium tetani live? |
In the soil, enters through a deep wound contaminated with soil |
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Where do Clostridium tetani spores germinate |
In anoxic conditions of deep wound |
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Tetanus is non-invasive, causes disease by action of ____/____ |
tetanus/toxin |
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Tetanus is transmitted from person to person. (T/F) |
False |
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What is effective at tetanus prevention? |
Toxoid vaccine |
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All tetanus cases occur in the inadequately immunized (T/F) |
True |
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In who is tetanus most commonly found? |
In 25-59 year old group |
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What happens if someone gets a serious cut and has concern for tetanus? |
Booster vaccine |
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What is the treatment for tetanus? |
Penicillin give to stop growth, antitoxin given to prevent new toxin from binding |
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Significant mortality still occurs with tetanus treatment. (T/F) |
True |
