BMD 330 Chapter 21 - Infectious Diseases Manifesting in the Cardiovascular and Lymphatic Systems Flashcards

The circulatory system is a closed system which carries oxygen to the tissues and carbon dioxide away.

• Heart - Pumps the blood
• Blood Vessels - Carry blood to and from all regions of the body
• Provides tissues with oxygen and nutrients
• Carries away carbon dioxide and waste products

• Carry blood away from the heart
• Arterioles are smaller branches

• Carry blood toward the heart
• Venules are smaller viens

• Smallest blood vessels
• Connect venules and arterioles

False; Deoxygenated blood comes toward the heart to get oxygenated.

Lymphatic System

• Mainly lymphatic vessels - Roughly parallel the blood vessels
• Lymph nodes - Cluster at the groin, neck, armpit, and intestines
• Spleen - Responsible for filtration, prevention of infection, and RBC and platelet storage

• Collects fluid that has left the blood vessels and entered tissues, filters it of impurities and infectious agents, and returns it to the blood
• Also used for fat transport and monitor for infectious agents

The cardiovascular system has access to the entire body, including the most sterilized environments like the brain --> So we need surveillance constantly and those are usually via WBCs

• WBCs
• Lymphocytes - Adaptive immunity
• Phagocytes - Critical to innate and adaptive immune responses

• Granular
• Non-Granular

• Lymphocyte - B and T cells
• Monocyte - Dendritic cells and Macrophages

• Eosinophil
• Neutrophil
• Basophil

in the blood or the condition involves the blood

Viruses that cause meningitis

Fungi in the blood

Presence of bacteria in the blood

• Bacteria flourishing and growing in the bloodstream
• Can lead to decreased blood pressure, which leads to septic shock

None; because it is a closed system

COVID-19 is caused by severe acute respiratory syndrome coronavirus starting a pandemic in December 2019.

Severe Acute Respiratory Syndrome Coronavirus #2

COVID-19 can access the cardiovascular system and can spread throughout the body.

False;

• Four other coronaviruses have infected humans causing minor upper respiratory infections.
• A different SARS virus caused an outbreak in 2003 starting in China
• In 2012, MERS-CoV started spreading in Middle Eastern countries

• It has been thought that the coronavirus have been circulating in bats for a very long time
• It experienced one or more mutations to make it capable of infecting, multiplying, and transmitting among humans
• Humans contracted it in a wildlife market in Wuhan, China in 2019

SARS-CoV-2 is one of the seven members of the Coronaviridae family that infects humans.

The S protein of the virus attaches to the ACE-2 host cell protein and uses it to initiate its entry into the cell

• Surface of cells in the lungs, brain, heart blood vessels, kidneys, liver, placenta, and GI tract

The viral particles of SARS-CoV-2 are transmitted via respiratory droplets

• Enveloped, positive-sense RNA viruses with spike (S) proteins

• The damage usually comes from the cytokine storm (cytokines are usually not directed, so they try to kill any live cells whether it is our cells or the microbe) and sometimes we can develop autoimmunity.
• Cytokines is usually what causes majority of the damage and the inflammation.

• Alpha - More contagious than the original virus
• Delta - Twice as transmissible than the original and more deadly
• Omicron - BA2 dominated in North America for the first half of 2022

• Most prominent is respiratory symptoms
• Infection can set off a cytokine storm, leading to hyperinflammation, both in lungs and in other organs, including digestive tract
• Systemic effects of the virus include skin rashes, muscle pain, heart damage, joint pain, and blood clots
• Considered Neurotrophic
• Up to one third of infections can be asymptomatic and many others are mild

• Loss of taste and smell, can lead to headaches and even long-term cognitive decline and dementia

• Mitigation efforts were initially put in place with the use of masks, social distancing, and handwashing.
• Emergency use authorization approval by the FDA in the United States was given to three vaccines
• Another vaccine (Paxlovid) was approved in late 2021 for patients with high risk for COVID complications, proved effective in controlling the infection if started soon after the infection

• Pfizer BioNTech and Moderna consist of mRNA coding for spike protein of SARS-CoV-2
• Johnson and Johnson is an adenovirus viral vector vaccine encoding for the SARS-CoV-2 spike protein

Inflammation of the inner lining of the heart (endocardium)

• Acute
• Subacute

• Damage to heart valves or prosthetic heart valves
• Can also be caused by vascular trauma or circulating immune complexes

• (> a week)
• Fever, anemia, abnormal heartbeat, symptoms of heart attack, shortness of breath, and chills
• Abdominal or side pain, Janeway lesions (painless when touched), and Osler's nodes (painful when touched)

• About a month
• Similar to acute endocarditis
• Develop more slowly and are less pronounced
• Enlarged spleen, clubbed fingers, and toes

The causative agent of acute endocarditis is Staphylococcus aureus, Streptococcus pyogenes, S. pneumoniae, and others.

The causative agent of subacute endocarditis is alpha-hemolytic streptococci

Parental

Endogenous transfer of normal biota to bloodstream

Sepsis is also known as septicemia which occurs when organisms are actively multiplying in the blood.

• Can be caused by many different bacteria and a few fungi

• Fever, altered mental state, shaking chills, and gastrointestinal symptoms
• Increased breathing rate, respiratory alkalosis, and low blood pressure resulting in loss of fluid from vasculature

Endotoxic show is a result of gram-negative bacteria multiplying in the bloodstream and releasing endotoxin (usually the LPS).

• Stimulate a massive inflammatory response mediated by cytokines
• Leads to drastic of blood pressure
• Gram-positive can instigate a similar series of events when fragments of the cell wall are released into the bloodstream

Cell wall or membrane components

• Pneumonic - Respiratory Disease
• Bubonic - Infection causes inflammation and necrosis of the lymph node or a bubo in the groin or axilla
• Septicemic ("Black Death") - Results in disseminated intravascular coagulation, subcutaneous hemorrhage, and purpura that degenerate into necrosis and gangreen; 30-50% mortality with treatment; 100% mortality without treatment

Yersinia pestis

Via fleas; usually found on animals like rats

• Respiratory droplets
• Looks similar to pneumonia
• Bloody/watery cough

• Bile of flea
• Swollen lymph nodes almost the size of eggs and they ooze pus

• Dissemination
• When bacteria is in the blood
• May experience gangreene

Only 3 to 50 cells

Tularemia

A zoonotic disease endemic throughout Northern Hemisphere

• Headache
• Backache
• Fever
• Chills
• Malaise
• Weakness

• Ulcerative skin lesions (most common sign to tell it is is Tularemia)
• Swollen lymph glands
• Conjunctival inflammation
• Sore Throat
• Intestinal Disruption
• Pulmonary involvement

30%

Francisella tularensis

Francisella tularensis is gram-negative and the infectious dose is 10 to 50.

Intracellular

• Rabbits and rodents
• Sometimes skunks, beavers, opossums, foxes, and other wild animals are also reservoirs

Lyme disease is a slow-acting, progressive syndrome in which bull's eye rash is an early symptom

• Fever, headache, stiff neck, and dizziness, joint pain, and swollen lymphs
• Progresses to cardiac and neurological symptoms
• Develops into crippling polyarthritis after several weeks to months

The causative agent of Lyme Disease is Borrelia burgdoferi which has a spirochete morphology.

It has the ability to adapt so it evades the immune system by changing antigens. It also has multiple proteins for attachment to host cells

• We (humans) are the accidental hosts, but primarily they infect small animals who are bitten by larval ticks.
• They infect small mammals and ingest the bacteria. These infected ticks grow up and develop and feed on larger animals such as deer. And this is also where they tend to mate. But again, we are the accidental host and we are usually not a part of the life cycle (it cannot replicate or get back into the cycle once it gets into us)

• Biological Vector (tick)

The Epstein-Barr virus causes mono or infectious mononucleosis.

Herpes Simplex 4

Epstein-Barr Virus contains circular form of DNA that is spliced into host cell DNA

Its latency and ability to splice into host cell DNA allows it to evade the host immune response.

Yes

• By adulthood, more than 90% of the world’s population has been infected with EBV
• Infection during the teen years results in disease about 30% to 77% of the time
• Usually, self-limiting

• Extreme fatigue and swollen spleen, which can cause spleen rupturing
• Can also cause sore throat and swollen limbs

• The pathogen multiplies in large numbers in the blood
• Septicemic anthrax is a possible outcome of all forms of anthrax
• Zoonotic disease of herbivores
• Infections can cause symptoms in various locations of the body:
• On the skin: cutaneous anthrax
• In the lungs: pulmonary anthrax
• In the gastrointestinal tract: gastrointestinal anthrax
• In the central nervous system: anthrax meningitis

Anthrax is usually found in the soil and affects primarily sheep and cattle.

Bacillus anthracis

• Gram-Positive Endospore-Forming Rod

Has a unique triple protein exotoxin (tripartite toxin) that causes a:

• Edema Factor: disruption to the water balance in host cells
• Lethal Factor: can combine with with edema and become a more lethal toxin; causes inflammation to the alveolar epithelium
• Protective Factor: Commonly use for targeting.

Aerobic

• Also catalase positive

• Agents that infect the blood and lymphatics
• Extreme fevers accompanied by internal hemorrhaging (internal bleeding from damaged blood vessels)
• Mainly caused by RNA viruses
• Distribution related to the distribution of Aedes genus of mosquito
• Prevalence fluctuates due to global warming patterns

They are all carried by Aedes mosquitoes

• Yellow Fever
• Dengue Fever
• Chikungunya
• Ebola and Marburg Fevers
• Lassa Fever

• Symptoms include fever, chills, severe headaches, and may transition to high fever, eventually yellowing of the skin and eyes.
• Jaundice and internal bleeding
• Currently, there is no treatment, but there are vaccines available
• More frequent in rainy climates
• Endemic in Africa and South America

• Usually asymptomatic or mild, but can cause high fever, headache, swollen glands, muscle aches, and if affected again, may have more severe symptoms, including persistent vomiting, bleeding gums or nose, as well as bloody stool and weakness, which may last long after clearing of other symptoms
• Endemic in Southeast Asia and Africa; epidemics have occurred in South and Central America and the Caribbean

• Marked by fever, severe joint pulling (especially in the hands, feet, knees, and ankles), headache, muscle pain, nausea, and sometimes rash
• No current treatments
• Vaccination is recommended, especially for those who are traveling to endemic areas
• Endemic in Africa; arrived in Central America in 2013 and in the United States and Europe in 2014

Cannot be transmitted by mosquitoes, but rather via respiratory droplets from infected animals and bodily fluids

Bats are thought to natural reservoir of Ebola

Capillary fragility is extreme and patients can bleed from their orifices and mucous membranes

• Ebola: Two phases: Dry that then turns into wet, where:
• Dry – Starts with fever, aches, pains, and fatigue
• Wet – Diarrhea, vomiting, and unexplained bleeding

Marburg fever begins with the high fever, severe headache, and severe malise. After 5 days of the disease, patients may develop hemorrhagic manifestations, and usually death is from bleeding out

• Cannot be transmitted by mosquitoes, but rather via respiratory droplets from infected animals and bodily fluids
• Similar to Marburg where symptoms become serious, like bleeding, face swelling, and shock.
• And if you eventually get over Lassa, long-term complications can include things like deafness
• Reservoir of virus is multimammate rat

• Characterized by a high fever but without fragility leading to hemorrhagic symtpoms
• Mostly caused by multiple bacterial species and one protozoan (Babesia) species

• Brucellosis
• Q Fever
• Cat-Scratch Disease
• Trench Fever
• Ehrilichiosis
• Anaplasmosis
• Spotted fever rickettsiosis

• Gram-Negative
• Coccobacilli

• Lives in the phagocytic cells that carry bacteria into the bloodstream causing focal lesions in the liver, spleen, bone marrow, and kidney
• Most prominent manifestation of human brucellosis is fluctuating pattern of fever, which is the origin of the common name undulant fever

Coxiella burnetti

Q in Q fever stands for query, due to the frustration in discovering the cause of the disease

Coxiella burnetti is a small, pleomorphic, gram-negative bacteria.

• It is a intraceullar parasite and forms and endospore-like structure

• Ticks play an essential role in transmission between wild and domestic animals, but not transmit the disease to humans.
• Transmitted by contact with infected animals.
• It is a natural species found in animals and can be found in much of their bodily fluid, especially animal products of birth and sometimes raw milk.
• Usually, people are unaffected or asymptomatic, but some will develop flu-like symptoms
• A very small percentage can develop chronic Q fever once infected which can eventually lead to endocarditis.

Cat-scratch disease is caused by Bartonella henselae

• Gram-Negative
• Rod
• Fastidious, will grow on blood agar

Infection connected with being clawed or bitten by a cat

• Present in over 40% of cats

When infected by Bartonella henselae, symptoms start 1 to 2 weeks afters and include:

• Cluster of small papules at the inoculation site
• Lymph nodes swell and become pus filled
• One-third of patients experience a high fever

Trench fever is caused by Bartonella quintana

Carried by lice, spread when louse feces enter a bite wound

• 5 to 6 days fever, leg pains, headache, chills, muscle aches, macular rash
• Endocarditis can develop

Rickettsia rickettsii

Hard Ticks

• Chills, fever, headache, muscular pain
• Distinctive spotted rash occurs 2 to 4 days after the prodome (initial stage)
• If untreated, lesions merge and become necrotic
• Cardiovascular disruption: hypotension, thrombosis, hemorrhage
• Treatment usually has to be done immediately and if untreated, it can cause serious cardiovascular complications

Malaria

48 or 72

• Malaise, fatigue, aches, nausea with or without diarrhea
• Chills, fever, and sweating

• Falciparum malaria: persistent fever, cough, and weakness for weeks without relief
• Cerebral malaria: small blood vessels in the brain become obstructed, leading to coma and death

Plasmodium

• Asexual phase: carried out in the human
• Sexual phase: carried out in the mosquito

Apicomplexans

• Invasion of merozoites into RBCs causes the release of fever-inducing chemicals into the bloodstream
• Plasmodium metabolizes glucose at a high rate
• Damage to RBCs causes anemia
• Accumulation of malarial products in the liver and immune stimulation in the spleen can lead to enlargement of these organs
• RBC adhesion to blood vessels in the brain adds to its virulence
• Parasite undergoes antigenic variation

Long-term mosquito abatement

• Elimination of standing water
• Spraying of insecticides
• Introducing sterile male mosquitoes into populations
• Mosquito nets, screens, repellants

Human chemoprophylaxis

• Prophylactic treatment for travelers
• A vaccine shows promise and is recommended for children in endemic areas

Retrovirus

True

• Pneumonia caused by Pneumocystitis jiroveci
• Kaposi’s sarcoma
• Sudden weight loss
• Swollen lymph nodes
• General loss of immune function

Signs and symptoms of HIV are tied to the level of virus in the blood and the level of T cells in the blood

To be diagnosed with AIDs, T cell count has be to less than 200.

• Fatigue
• Diarrhea
• Weight loss
• Neurological Changes

• Opportunistic infections and neoplasms
• Severe immune deregulation, hormone imbalances, and metabolic disturbances
• Weight loss, diarrhea, and poor nutrient absorption
• Protracted fever, fatigue, sore throat, and night sweats
• Lesions on the brain, meninges, spinal column, and peripheral nerves

Retrovirus in the genus Lentivirus

• Contains reverse transcriptase that catalyzes the replication of double-stranded DNA from single-stranded RNA
• Viral genes become permanently integrated into the host genome

• HIV-1
• HIV-2

HIV-1

1. Virus is absorbed and endocytosed, and the twin RNAs are uncoated. Reverse transcriptase catalyzes the synthesis of a single complementary strand of DNA (ssDNA). This single strand serves as a template for synthesis of a double stranded DNA. In latency, dsDNA is inserted into the host chromosome as provirus

2. After latent period, various immune activators stimulate the infected cell, causing reactivation of provirus genes and production of viral mRNA

3. HIV mRNA is translated by the cell's synthetic machinery into virus components (capsid, reverse transcriptase, spikes), and the viruses are assembled. Budding of mature viruses lyses the infected cell

Any form of intimate contact involving transfer of blood can be potential source of infection

• Trauma and needle sharing
• Sexual transmission
• Breast milk

Urine, tears, sweat, and saliva are not considered sources of infection

• Since the beginning of the epidemic in the 1980s, 60 million have become infected and more than 30 million have died of HIV-related causes worldwide

Global estimate:

• 38 million infected worldwide
• 1.2 million infections currently in the United States
• In the United States, 15% of those infected with HIV are unaware

A person is diagnosed as having HIV infection if they have tested positive for exposure to the human immunodeficiency virus

• This diagnosis is not the same as having AIDS

Viral testing is based on detection of antibodies specific to the virus in serum or other fluids

• ELISA
• Latex agglutination
• Rapid antibody tests

Diagnosis with Stage 3 HIV infection requires both:

• Test positive for the virus
• CD4 count of fewer than 200 cells per microliter of blood

• Avoidance of unprotected sexual contact with infected persons
• Barrier protection should be used when having sex with anyone whose HIV status is unknown
• Not sharing needles or by cleaning needles with bleach and then rinsing before another use
• HIV-positive individuals with uninfected partners should begin a regimen of antiretroviral drugs
• Clinical trials of various vaccines are ongoing

• Treatment should begin immediately after HIV diagnosis

• Antiviral chemotherapy and a variety of drugs to prevent or treat opportunistic infections and other complications such as wasting disease
• Three-drug cocktail containing two nucleoside analog reverse transcriptase inhibitors and one nonnucleoside reverse transcriptase inhibitor

• Nucleoside analogs that inhibit reverse transcriptase - Inserted in place of the natural nucleotide by reverse transcriptase but block further action of the enzyme and synthesis of viral DNA. Non-nucleotide RT inhibitors are also in use.
• Protease inhibitors - Plug into active sites on HIV protease. This enzyme is necessary to cut elongated HIV protein strands and produce functioning smaller protein units. Because the enzyme is blocked, the proteins remain uncut, and abnormal defective viruses form.
• Integrase inhibitors - Attach to the enzyme required to splice the dsDNA from HIV into host genome. This will prevent formation of the provirus and block future virus multiplication in that cell

• Gram-Positive Endospore-Forming Bacteria
• Causes Anthrax

• Gram-Positive Bacteria
• Causes Acute Endocarditis

• Gram-Positive Bacteria
• Causes Acute Endocarditis

• Gram-Negative Bacteria
• Causes Plague

• Gram-Negative Bacteria
• Causes Lyme Disease

• Gram-Negative Bacteria
• Causes Cat-Scratch Disease

• Gram-Negative Bacteria
• Causes Spotted Fever Rickettsiosis

• DNA Virus
• Causes Infectious Mononucleosis

• RNA Virus
• Causes COVID-19

• RNA Virus
• Causes Hemorrhagic Fever

• Retroviruses
• Causes HIV infection and AIDs