Infections of the Cardiovascular System

Defenses of the Cardiovascular and Lymphatic Systems

Cardiovascular system is highly protected, however, if microbes do invade they gain
access to every part of the body
Bloodstream infections are systemic infections; often with the suffix emia (Viremia,
Fungemia, Bacteremia, Septicemia)
Defenses in the bloodstream- leukocytes

ENDOCARDITIS

Inflammation of the endocardium; infection of the valves of the heart

Types: Acute and subacute, with similar symptoms (in subacute the symptoms develop
more slowly and are less pronounced)
S/S: Fever, anemia, abnormal heartbeat (similar to heart attack), Abdominal or side pain,
petechiae over the upper half of the body and under the fingernails may be present,
subacute cases - enlarged spleen

HIV

lentivirus genus of retroviruses

HIV-1
four distinct lineages - groups M, N, O, and P result of independent cross-species
transmission eventEO
Group M
first to be discovered
pandemic form of HIV-1
found in virtually every country on the globe
Group O
discovered in 1990
less prevalent than group M
<1% of global HIV-1 infections
restricted to Cameroon, Gabon, and neighboring countries
Group N
identified in 1998
less prevalent than group O
Cameroon
Group P
discovered in 2009
Cameroonian woman living in France

HIV-1
evolves 1 million times faster than mammalian DNA
reverse transcriptase is error prone
viral generation time is short

HIV-2
 significantly less transmissible than HIV-1
near complete absence of mother-to-infant transmissions
mostly do not progress to AIDS

How humans acquired the ape precursors of HIV-1 groups M, N, O, and P

not known
hypothesis : cutaneous or mucous membrane exposure to infected ape blood and/or body
fluids
bushmeat huntings

Stages of HIV disease

Acute infection
acute retroviral syndrome (ARS) or primary HIV infection
incubation period: 2 to 4 weeks after infection
flu-like symptoms
active viral replication viral load very high
CD4 cells fall quickly.
HIV spread is highest

2. Clinical latency (inactivity or dormancy)

asymptomatic HIV infection or chronic HIV infection
HIV still active, but reproduces at very low levels
can be asymptomatic
antiretroviral therapy (ART) may live with clinical latency for several decades
middle and end of this period
viral load increased
CD4 cell count decreased

3. AIDS (acquired immunodeficiency syndrome)

badly damaged immune system
CD4 count <200 cells/mm3 of blood
symptoms
swollen lymph nodes
weight loss
fever
diarrhea
cough
without treatment vulnerable to opportunistic illnesses
tuberculosis
Mycobacterium avium-intracellulare
Cryptococcal meningitis
Cryptococcus neoformans
cancers
Lymphomas
Kaposi's sarcoma
 pneumonia

Transmission
exchange of body fluids from infected individuals
blood, breast milk, semen and vaginal secretions
cannot become infected through ordinary day-to-day contact
kissing, hugging, shaking hands, or sharing personal objects, food or water.

Risk factors
unprotected anal or vaginal sex
having another sexually transmitted infection
syphilis
herpes
chlamydia
gonorrhea
bacterial vaginosis

sharing contaminated needles, syringes and other injecting equipment and drug solutions
when injecting drugs
receiving unsafe injections, blood transfusions, medical procedures that involve unsterile
cutting or piercing
experiencing accidental needle stick injuries, including among health workers.

Diagnosis
Screening tests
not confirmatory
rapid diagnostic tests (RDTs) and enzyme immunoassays (EIAs)
antibodies to HIV-1/2 and/or HIV p24 antigen
Confirmatory tests
western blot (WB) and immunofluorescence assays (IFA)
US Centers for Disease Control and Prevention (CDC) and the Association of Public
Health Laboratories (APHL)
initial Ag/Ab assay followed by HIV-1/HIV-2 antibody differentiation immunoassay
instead of WB for confirmatory testing
Bio-Rad Multispot HIV-1/HIV-2
Bio-Rad Genius HIV1/2 confirmation assay

HIV testing services

voluntary, right to decline testing should be recognized
must include the 5 Cs recommended by WHO
informed Consent
Confidentiality
Counselling
Correct test results
 Connection (linkage to care, treatment and other services)

Prevention
o Male and female condom use
correct and consistent use
male latex condoms - 85% or greater protection against HIV and other STIs
o Testing and counselling for HIV and STIs
strongly advised for all people exposed to any of the risk factors
o Voluntary medical male circumcision
reduces the risk of heterosexually acquired HIV infection in men by approximately 60%
o Antiretroviral (ART) use for prevention
as prevention
HIV(+) person adheres to an effective ART regimen: risk of transmitting the virus to
uninfected sexual partner can be reduced by 96%
couples in which one partner is HIV(+) and the other HIV(-), ART for the HIV(+) partner
regardless of her/his CD4 count.
Pre-exposure prophylaxis (PrEP) for HIV(-) partner
daily use by uninfected people to block acquisition of HIV
reduced HIV transmission
Post-exposure prophylaxis for HIV (PEP)
use within 72 hours of exposure to HIV
includes counselling, first aid care, HIV testing, and a 28-day course of ARV drugs with
follow-up care
people accidentally exposed to HIV
health workers
unprotected sexual exposures or sexual assault.

o Harm reduction for injecting drug users

use sterile injecting equipment

o Elimination of mother-to-child transmission of HIV (eMTCT)

vertical or mother-to-child transmission (MTCT).
absence of any interventions transmission rate is 15-45%.
WHO: ARVs to mothers and infants during pregnancy, labour and the post-natal period,
and offering life-long treatment to HIV(+) pregnant women regardless of CD4 count

Treatment
suppressed by combination ART 3 or more ARV drugs
ART
does not cure HIV infection
controls viral replication within a person's body
allows an individual's immune system to strengthen and regain the capacity to fight off
infections
hemorrhagic fever
Caused by viruses in one of four families:
Arenaviridae
Filoviridae
Flaviviridae
Bunyaviridae

Dengue Fever
Usually mild
Sometimes it can progress to dengue hemorrhagic shock syndrome
Causes severe pain in muscles and joints

Dengue
transmitted by female mosquitoes
Aedes aegypti
A. albopictus
widespread throughout the tropics
severe dengue (Dengue Haemorrhagic Fever)
first recognized in the 1950s, in Philippines and Thailand
most Asian and Latin American countries leading cause of hospitalization and death
among children
serotypes: DEN-1, DEN-2, DEN-3, DEN-4
cross-immunity after recovery partial, temporary
subsequent infections by other serotypes increase the risk of developing severe dengue

Transmission
bites of infected female Aedes aegypti mosquito
infected mosquito - capable of transmitting the virus for the rest of its life
infected humans
main carriers and multipliers of the virus
source of the virus for uninfected mosquitoes
transmit the infection (for 45 days; maximum 12) via Aedes mosquitoes after their first
symptoms appear

Aedes aegypti
primary vector
lives in urban habitats, breeds mostly in man-made containers
day-time feeder; peak biting periods - early in the morning and in the evening before
dusk

Aedes albopictus
secondary dengue vector in Asia
has spread to North America and Europe
via international trade in used tyres (a breeding habitat) and other goods (e.g. lucky
bamboo)
 adaptive, can survive in cooler temperate regions

Signs and Symptoms

last for 27 days, after an incubation period of 410 days after the bite from an infected
mosquito
severe flu-like illness
high fever (40C/104F) accompanied by 2 of the following symptoms:
severe headache
pain behind the eyes
muscle and joint pains
nausea
vomiting
swollen glands
rash

severe dengue
potentially deadly
complication
plasma leaking
fluid accumulation
respiratory distress
severe bleeding
organ impairment

Warning signs:
37 days after the first symptoms and there is decrease in temperature (below
38C/100F) accompanied by
severe abdominal pain
persistent vomiting
rapid breathing
bleeding gums
fatigue
restlessness
blood in vomit
next 2448 hours critical stage, can be lethal; proper medical care is needed to avoid
complications and risk of death

Treatment
no specific treatment
maintenance of the patient's body fluid volume

Immunization

Prevention and control

combat vector mosquitoes through:
prevent mosquitoes from accessing egg-laying habitats by environmental management
 and modification;
disposing of solid waste properly and removing artificial man-made habitats;
covering, emptying and cleaning of domestic water storage containers on a weekly basis;
applying appropriate insecticides to water storage outdoor containers;
using of personal household protection such as window screens, long-sleeved clothes,
insecticide treated materials, coils and vaporizers;
improving community participation and mobilization for sustained vector control;
applying insecticides as space spraying during outbreaks as one of the emergency vector-
control measures;
active monitoring and surveillance of vectors should be carried out to determine
effectiveness of control interventions.

Ebola Virus
enveloped
negative-sense RNA virus
cylindrical, tubular
Family Filoviridae
Genus Ebolavirus
Species Zaire ebolavirus

Filoviridae
three genera:
Cuevavirus
Marburgvirus
Ebolavirus
five species - Zaire, Bundibugyo, Sudan, Reston, Ta Forest
Bundibugyo ebolavirus, Zaire ebolavirus, and Sudan ebolavirus - associated with large
outbreaks in Africa
Zaire species - 2014 West African outbreak.

Ebola virus disease (EVD)

acute, serious illness which is often fatal if untreated
first appeared in 1976 in 2 simultaneous outbreaks
Nzara, Sudan
Yambuku, Democratic Republic of Congo
occurred in a village near the Ebola River

current outbreak in West Africa (first cases notified in March 2014)

largest and most complex Ebola outbreak since its first discovery in 1976
spread between countries starting in Guinea then spreading across land borders to Sierra
Leone and Liberia, by air (1 traveller) to Nigeria and USA (1 traveller), and by land to
Senegal (1 traveller) and Mali (2 travellers)

Transmission
fruit bats (Pteropodidae family) - natural Ebola virus hosts
 introduced into the human population
close contact with the blood, secretions, organs or other bodily fluids of infected animals
(chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines)

human-to-human transmission is via direct contact (through broken skin or mucous

membranes) with the blood, secretions, organs or other bodily fluids of infected people, and
with contaminated surfaces and materials
risks of sexual transmission - more surveillance data and research are needed
risk factors
health-care workers
burial ceremonies
people remain infectious as long as their blood contains the virus

Symptoms of Ebola virus disease

incubation period - 2 to 21 days
humans not infectious until they develop symptoms
early symptoms
sudden onset of fever
fatigue
muscle pain
headache
sore throat

early symptoms followed by

vomiting
diarrhea
rash
symptoms of impaired kidney and liver function
internal and external bleeding (e.g. oozing from the gums, blood in the stools)

Diagnosis - difficult to distinguish from malaria, typhoid fever, and meningitis

confirmation of symptoms by:
enzyme-linked immunosorbent assay (ELISA)
antigen-capture detection tests
serum neutralization test
reverse transcriptase polymerase chain reaction (RT-PCR) assay
electron microscopy
virus isolation by cell culture
samples extreme biohazard risk
laboratory testing conducted under maximum biological containment conditions

Treatment and vaccines

no proven treatment available
supportive care
rehydration with oral or intravenous fluids
treatment of specific symptoms
 potential treatments including blood products, immune therapies and drug therapies
being evaluated
no licensed vaccines are available yet, but 2 potential vaccines are undergoing human
safety testing

Risk reduction messaging focus:

Reducing the risk of wildlife-to-human transmission
contact with infected fruit bats or monkeys/apes, consumption of their raw meat
animals handled with (personal protective equipment) PPE
animal products (blood and meat) thoroughly cooked before consumption
Reducing the risk of human-to-human transmission
direct or close contact with people (bodily fluids) with Ebola symptoms
use of gloves and other PPE
regular hand washing
Reducing the risk of possible sexual transmission
risk of sexual transmission not be ruled out
those who have recovered should abstain from all types of sex for at least 3 months after
onset of symptoms
if abstinence is not possible use of male or female condom
contact with body fluids avoided, wash with soap and water
Outbreak containment measures
prompt and safe burial of the dead
identify those who may have been in contact with infected patients, monitor health for 21
days
separate the healthy from the sick to prevent further spread
good hygiene, clean environment

Controlling infection in health-care settings:

standard precautions regardless of presumed diagnosis
basic hand hygiene
respiratory hygiene
use of PPE
safe injection practices
safe burial practices
extra infection control measures to prevent contact with
blood and body fluids
contaminated surfaces/materials (clothing, bedding)
if in close contact (within 1 metre)
wear face protection
clean, non-sterile long-sleeved gown
gloves
samples from humans and animals
handled by trained staff
suitably equipped laboratories
 Chikungunya
mosquito-borne
outbreak in southern Tanzania, 1952
RNA virus family Togaviridae, genus alphavirus
chikungunya Kimakonde language to become contorted stooped appearance of
sufferers with joint pain (arthralgia)

Signs and symptoms

abrupt onset of fever
joint pain (very debilitating), muscle pain, headache
nausea
fatigue
rash
occasional cases: eye, neurological and heart complications, gastrointestinal complaints
symptoms usually mild, may go unrecognized, misdiagnosed as dengue

Transmission
bites of infected female Aedes aegypti and Aedes albopictus
bite throughout daylight hours, (early morning and late afternoon
onset of illness : 4-8 days after getting bitten, but can ranger between 2 to 12 days

Diagnosis
serological tests
ELISA IgM and IgG anti-chikungunya antibodies
virological methods
RT-PCR for genotyping
virus isolated from blood during the first few days of infection

Treatment
no specific antiviral drug
relieve symptoms
joint pain anti-pyretics
optimal analgesics
fluids
no commercial chikungunya vaccine

Prevention and control

reduce the number of habitats that support mosquito breeding
insecticides to kill flying mosquitoes
during outbreaks
clothing which minimizes skin exposure to the vectors
repellents
DEET (N, N-diethyl-3-methylbenzamide)
IR3535 (3-[N-acetyl-N-butyl]-aminopropionic acid ethyl ester)
 icaridin (1-piperidinecarboxylic acid, 2-(2-hydroxyethyl)-1-methylpropylester)
insecticide-treated mosquito nets
mosquito coils, insecticide vaporizers