chapter 21

septicemia

any microbial infection of the blood that produces illness

• fever, chills, nausea, vomiting, diarrhea, malaise

• septiv shock can develop rapidly

• small hemorrahgic lesions called petechiae develop

• osteomyelitis occurs if bacteria invade the bones

• toxemia symptoms vary depending on the toxin

  • exotoxin

  • entotoxin

bacteremia

bacterial septicemia

• fever, chills, nausea, vomiting, diarrhea, malaise

• septiv shock can develop rapidly

• small hemorrahgic lesions called petechiae develop

• osteomyelitis occurs if bacteria invade the bones

• toxemia symptoms vary depending on the toxin

  • exotoxin

  • entotoxin

toxemia

release of bacterial toxins into the blood

• fever, chills, nausea, vomiting, diarrhea, malaise

• septiv shock can develop rapidly

• small hemorrahgic lesions called petechiae develop

• osteomyelitis occurs if bacteria invade the bones

• toxemia symptoms vary depending on the toxin

  • exotoxin

  • entotoxin

lymphangitis

infection and inflammation of the lymphatic vessels

endotoxin

toxin released from living organism

exotoxin

toxin released from gram negative bacteria

oppurtunistic or HAI

what type of pathogens are the cause of Septicemia, Bacteremia, and Toxemia

gram negative bacteria

what is septicemia often caused by

• activates various defense reactions in th ebody

immunocompetent

__ individuals rarely have septicemia

• bacterial infections self-limited in these people

inoculation

septicemia is due to direct ___ of bacteria into th eblood

endocarditis

signs

• inflammationof the endocardium

• fever, fatigue, malasie, and difficulty breathing

• tachycardia may be detected

diagnosed

• based on symptoms

• echocardiogram

• treated with intravenous antibacterial drugs

• prophylactic antibiotics for high-risk pateins when needed

viridans streptococci (commensals)

this pathogen cause almost half of endocarditis cases

the other half usually normal microbiota are responsible

• patients usually have obvious source of infection

• patients with abnormal heart have increased risk

• embolus can blood vessels in other organs

brucellosis

• fluctuating fever that spikes every afternoon

• diagnosed by serological tests and presence of fever

• usually requires no treatment

brucella melitensis strains

the pathogen that causes brucellosis

• endotoxin causes some of the signs and symptoms

• you get it from consumption of contaminated dairy products

• contact with animal blood, urine, or placentas

tularemia

• skin lesions and swollen lymoh nodes at infection site

• ascending lymphangitis

• diagnosis is difficult and requires sergological confirmation

• treated with antimicrobials

• vaccine availavle for people at risk for exposure

francisella tularensis

pathogen that causes tularemia

• diverse host range includes mammals, brds, fish, ticks, and insects

• an survive within infected cells

• endotoxin causes many signs and symptoms

• transmitted via bite of infected tick or contant with infected animal

• small size of bacteria allows entry through seemingly unbroken skin

• individuals in contact with dead animals at highest risk

plague

two types

• bubonic

• pneumonic

diagnosis is based on characteristic symptoms

must be diagnosed and treated immediately

treated with various antimicrobial drugs

prevented with rodent and flea control and good hygiene

yersinia pestis

the pathogen for plague

adhesins, type III secretion systems, capsuls, and antiphagocytic proteins

transmitted by contact with infected animal or flea feces

bubonic plague fatal in 50% of cases if untreated

pneumonic plague fatal in 100% of cases if untreated

bubonic plague

characterised by enlarged lympthnodes called buboes

fatal 50% of cases if left untreated

penumonic plague

• occurs when bacterium spreads to the lungs

• difficulty breathing can develop rapidly

• fatal 100% of cases if left untreated

lyme disease

signs

• three phases in untreated patietns

  • bull’s eye rash at infection site

  • neurological symptoms

  • severe arthritis

one of the most reported vector-borne disease in the us

three events contributed to an increase in the disease

• movement of human populations into woodland areas

• protection of the deer population

• coyotes have displaced the foxes that help control the mouse population

DEET

what should be in the repellents when attempting to prevent lyme disease

borrelia burgdorferi

the pathogen that causes lyme disease

• use of manganese instead of iron circumvents host defense

• avoids immune detection by altering membrane proteins

ehrlichiosis and anaplasmosis

signs

• resembles the flu

• leukopenia and thrombocytopenia also occur

both considered emerging diseases

• diagnosis is difficult since symptom resembles other diseases

• antimicrobials effective against both bacteria

• prevention involves avoiding tick-infested areas

ehrlichia chaffeensis

the pathogen that causes ehrlichiosis

live inside infected cell

tick transmit bacteria to humans

anaplasma phagocytophilum

pathogen that causes anaplasmosis

live inside infected cell

tick transmit bacteria to humans

infectious mononucleosis

signs

• severe sore throat and fever occur initially

• followed by swollen lymph nodes, fatigue, appetite loss, and skin rash

diagnosed by presence of large, lobed B lymphocytes and neutropenia

treatment focuses on reliving symptoms

prevention is difficult since EBV occurence is widespread

Epstein-Barr virus (EBV) (HHV-4)

the pathogen that caues infectious mononucleosis

• establishes latent infection in host

  • supresses apoptosis of infected B cells

• is implicated in a number of other diseases

• transmission occurs via saliva

• infects b lymphocytes

• majority of adults have antibodies against EBV

Yellow fever

signs

• low fever, headacge, muscle aches, vomiting

• remission- then delirium,seziures,coma, degeneration of liver, kidneys, heart, massive hemorraging-fever, nausea, nosebleed, shock, death

  • black vomit

  • jaundice

diagnosis, treatment, prevention

• primarilty in afria, although many outbreaks occured in history of US since 1600s

• essentially eradicated in the western hemisphere )but there are reservoirs)

aedes mosquito

how is yellow fever transmitted

how is degue and dengue hemorrhagic fever tranmitted

Flaviviridae (+ssRNA virus)

pathogen for yellow fever

transmission via mosquito bite

liver—> 3-6 days later symptoms, 20%morality if severe

cytomegalovirus

signs

• asymptomatic in most cases

• complications in neonates and immunocompromised

diagnosed by identifying enlarged cells with inclusions

fomivirsen is administered for eye infections

no vaccine is available

cytomegalovirus

what is the pathogen that causes cytomegalovirus

• transmit by direct contact with bodily fluids or transplacentally one of the most common infections of humans

dengue fever

first phase: fever edema, head and muscle pain

second phase: return of fever and red rash

usually milder of the two diseases

diagnosed based on signs adn symptoms in people who have travelled to endemic regions

no specific treatment is available

prevention requires control of mosquitoes

dengue hemorrhagic fever

internal bleeding, shock, and possible death

more severe than other and can be fatal

distribution of diseases has spread

diagnosed based on signs adn symptoms in people who have travelled to endemic regions

no specific treatment is available

prevention requires control of mosquitoes

4

how many strains of dengue are there

african viral hemorrhagic fever

signs

• fever adn fatigue

• minor petechiae progresses to severe internal bleeding

diagnosis, treatment, prevention

• diagnosis is based on characteristic symptoms and presence of virus in the blood

• treatment involves fluid and electrolyte replacement

• vaccines are being studied for their effectiveness in humans

ebolavirus or marburgvirus

pathogen that causes hemorrhagic fever

malfunctioning blood clotting cause hemorrhaging

occurs primaroly in africa

transmitted via contact with bodily fluids of infected individuals

malaria

signs

• associated with parasites life in erythrocytes

  • fever, chills, diarrhea, headache

  • anemia, weakness, and fatigue gradullay occur

endemic throughout tropics and subtropics

causes more than 1 million deaths annually with millions more infected

diagnosis made by identifying plasmodium in blood

treated with antimicrobials, some strains are resistant

prevention required control of mosquiotes

plasmodium

causes malaria

• severity of disease depends on species

• children are particulaty vulnerable to infection

• certain genetic traits increase resistance

  • presence of sickle cell gene

  • presence of two genes for hemoglobin C

  • genetic deficiency of G6PD

  • lack of duffy antigens on erythrocytes

P. falciparcum

causes the most severe malaria

reproductive

in malaria what body cycle hides parasite from immune surveillance

host cells

malaria secretome injects toxins into ___

merozites

what forms within vesicles and avoid detection in malaria

toxoplasmosis

signs

• majority of cases have no symptoms

• people with poor immunity may have

  • fever, malaise, and inflammation of lung, liver, adn heart

• fetak infections can cause numerous conditions, including spontaneous abortion or stillbirth

diagnosis, treatment, prevention

• diagnosed manily by detection of organism sin tissues

• treatment needed only in AIDS patients, pregnant women, and newborns

• prevention is difficult since T. gondii has humerous hosts

toxoplasma gondii

the pathogen for toxoplasmosis

• cats are the definitive host

• infects and lives in many cell types

• you can get it by consuming undercooked meat containin the parasite

• tranmission across the placenta can also occur

• specific mechanism of disease is not yet known

chagas disease

• swelling at infection site and non specific symptoms

• chronic manifestations can occur years after infection

• diagnosed by microscopic identification of T. cruzi or xenodiagnoces

• most pateitns show no early symotoms adn late staes of the disease cannot be treated

• prevention involved avoidance of triatoma bugs

trypansoma cruzi

pathogen that causes chagas disease

• endemic throughout central adn south america

• most animals harbor it

• evades immune system in several ways

  • lives inside host cells

  • changes its surface antigens

  • auppresses production of immune cytokines

• transmitted through the bite of infected triatoma or transfusion with infection blood

• progresses through four stages over several months

schistosomiasis

• swimmers itch may occur at infection site

• eggs deposited throughout body can cause other symptoms

• diagnosed by identifying eggs in stool or urine sample

• treated with praziquentel

• prevention requires avoiding potentially contaminated water

schistosoma

3 species of the pathogen that causes schistosomiasis

• each species is geographilcally limited

• humans are principal host for most species

• is not found in the US