Infectious Diseases Exam 3 study guide

STD - Ophthalmia Neonatorum

(conjunctivitis of the newborn) Main Causes: A mother's existing gonorrheal or chlamydial infections • Gonococcal or chlamydial ophthalmia neonatorum can cause corneal scarring, ocular perforation, and blindness as early as 24 hours after birth. Treatment: prophylactic ocular topical medication • *erythromycin ophthalmic ointment • silver nitrate or tetracycline - no longer given in the U.S.

Airborne Viral Diseases • Rubella (German Measles)

- A highly infectious RNA virus, it is the mildest rash-forming virus - Endemic worldwide - Transmitted usually by respiratory secretions (urine also) - Asymptomatic carriers may transmit the virus - The characteristic rash starts on the face and progresses down the trunk and to the extremities; it resolves in about three days - Prenatal transmission of rubella can cause cardiac lesions, deafness, ocular lesions resulting in blindness, and mental and physical retardation - Immunization has been very successful, declared eradicated from the United States in 2004 • Rubella elimination is defined as the absence of continuous disease transmission for 12 months or more in a specific geographic area. Rubella is no longer endemic (constantly present) in the United States.

Airborne Viral Diseases • Prenatal transmission of rubella can cause serious complications in fetus if mother is infected during first trimester of pregnancy

- Cardiac lesions - Deafness - Ocular lesions resulting in blindness - Glaucoma - Mental and physical challenges

Airborne Viral Diseases • Severe Acute Respiratory Syndrome (SARS)

- Caused by an RNA coronavirus (SARS-CoV) - The 2002-2003 pandemic of SARS-CoV • Caused 8,096 cases and 774 deaths • Began in a rural area in China • Eventually spread to some 37 countries - Transmitted by respiratory droplets and fomites - Symptoms are flulike—cough, fever, myalgia, sore throat, and shortness of breath

Sexually Transmitted Viral Infections • Genital Herpes

- Caused by the DNA virus herpes simplex virus type 2 (HSV-2) - Causes painful and itchy sores on the penis or on the labia, vagina, and cervix in females; infection is lifelong, with recurrent episodes - Prompt treatment with antiviral drugs is somewhat effective but is not a cure - There is no vaccine; prevention is based on safe sex practices - Transmission is through direct contact with herpes sores, until they heal, and by asymptomatic carriers - Pregnant women with HSV-2 are at increased risk for miscarriage and possibly cervical cancer

Sexually Transmitted Viral Infections • Genital Warts

- Cervical cancer is the fifth leading cause of cancer • Some HPV strains (70% are type 16 and 18) are linked to cancer, including cervical, vulvar, anal cancer, cancer of the penis and prostate cancer • Types 6 and 11 can cause cancer, but cause 90% of genital warts - More than 50% of sexually active U.S. males and females will be infected during their lifetime - Prevention is by avoiding contact with the virus; a vaccine that prevents the infection by four HPV types (6, 11, 16, 18), was approved in 2006 (Gardasil-9) - Cervarix - GlaxoSmithKline(GSK) stop supplying Cervarix in the U.S. due to very low market demand. - CDC recommends girls age 11 or 12 be vaccinated and a catchup booster vaccination at ages 13-26. - CDC recommends boys ages 13-21 should also be vaccinated.

Airborne Viral Diseases • Chickenpox Varicella Zoster, a DNA herpes virus, is the cause of chickenpox and shingles

- Chickenpox usually occurs in children - Early signs of chickenpox are fever, headache, aches and pains, followed in a few days by an itchy rash with fluid-filled vesicles appearing on the scalp, face, trunk, and extremities

Foodborne and Waterborne Infection • E. coli (enterohemorrhagic E. coli)

- Contaminates rare meat, particularly hamburgers, also fresh spinach, sprouts, etc. - Hemolytic uremic syndrome may result in death in children under age five

Airborne Viral Diseases • Smallpox

- DNA virus (Variola) deemed eradicated from globe through vaccination - Humans are the only host for Variola virus - Transmitted directly by droplets or by fomites (bedding, etc.) - The first week has highest number of viruses in saliva - Symptoms include high fever, fatigue, headaches, and backaches, followed by rash of red, pus-filled lesions that leave permanent scars - Fatality rate is about 30%

Contact Diseases and Bloodborne Viral Diseases • Infectious Mononucleosis

- Diagnosis requires detection of antibodies and abnormal white blood cells - Infection occurs primarily in the 15 to 30 age group - There is no specific treatment, and symptoms generally disappear in four to six weeks; recurrences can occur, but are rare - Burkitt's lymphoma, a malignant cancer of the jaw and abdomen that occurs in children in central and western Africa is caused by Epstein-Barr Virus (EBV) - 2012 research reveals that EBV and Human papillomavirus (HPV) 16 and 18 viral DNA sequences found in normal and cancerous prostate tissues

Bacteria that causes gastroenteritis:

- E. coli - Salmonella - Campylobacter - campylobacteriosis - Shigella - shigellosis

Airborne Viral Diseases • Measles (Rubeola), Mumps, and German Measles (Rubella)

- Each is of these childhood illnesses is caused by a specific RNA virus - The MMR vaccine was introduced in 1968 • MMR consists of a mixture of live, attenuated measles, mumps, and German measles viruses • The vaccine has drastically reduced the incidence of these diseases, but immunization remains necessary to maintain herd immunity

Airborne Viral Diseases • Hantavirus Pulmonary Syndrome (HPS)

- First reported in 1993 in the Four Corners area of the United States - Hantaviruses are RNA viruses; known as hemorrhagic viruses in Africa since the 1930s - Severe influenza-like respiratory illness complicated by respiratory failure and, in some cases, death (fatality rate is 6% to 8%) - The Sin Nombre strain that causes HPS attacks the lungs with over a 60% fatality rate - The disease primarily strikes young, healthy adults • When death occurs, it usually does so only days after infection • Accumulation of fluid occurs in the lungs, which interferes with oxygen diffusion; oxygen therapy is required

Contact Diseases and Bloodborne Viral Diseases Rabies

- Formerly known as hydrophobia, it is caused by an RNA virus - Untreated mortality rate is almost 100% - A rabies vaccine is available for both prevention and early treatment - Two lethal forms of rabies are: • Furious rabies (about 80% of cases) involves the brain, and is characterized by aggressiveness, excitability, and foaming at the mouth • Dumb or paralytic rabies primarily involves the spinal cord; animals have weak limbs and are unable to raise their heads or make sounds due to paralysis of the neck and throat muscles - Rabies is a worldwide zoonotic disease with many animal reservoirs (coyotes, skunks, cats, bats, foxes, raccoons, mongooses and domestic animals) - The recombinant rabies vaccinations are painlessly injected in the arm (earlier vaccines were administered into the abdomen and were painful) - In the U.S. • Human cases usually associated with rabid bat bites - In Southeast Asia and developing countries • Human cases usually associated with rabid dog bites

Contact Diseases and Bloodborne Viral Diseases • Hepatitis B, C, and D Viruses

- HBV is a DNA virus whereas Hepatitis C and D are RNA viruses - Several hepatitis viruses are transmitted by blood and blood products and by sexual practices - Pregnant women can transmit the viruses to their infants - HBV and HCV are frequently found coinfecting AIDS patients - HBV and HCV infections can be asymptomatic or cause chronic diseases, resulting in serious liver problems and possibly requiring a liver transplant

Contact Diseases and Bloodborne Viral Diseases • Hepatitis B virus (HBV)

- HBV is an occupational hazard for some health professionals - Infection can also be acquired by sharing needles, tattooing, acupuncture, and ear piercing - Globally, 350 million people live with a chronic infection, and over 620,000 die each year - A vaccine has reduced the incidence of acute HBV in all age groups, but it is too expensive for developing countries

Contact Diseases and Bloodborne Viral Diseases • Hepatitis D virus (HDV)

- HDV is a defective virus and cannot replicate without HBV - Coinfection with HBV and HDV results in a greater likelihood of liver disease than does HBV alone - HBV/HDV coinfection carries a 20% mortality rate, the highest rate of all the hepatitis viruses - HDV is rare in developed countries and is primarily associated with intravenous drug use - Although no vaccine is available for hepatitis D, vaccination with the hepatitis B vaccine can protect people from HDV infection.

Contact Diseases and Bloodborne Viral Diseases • Hepatitis C virus (HCV)

- Hepatitis C is a chronic bloodborne illness; it may be subclinical or mild; about 50% of the cases progress to chronic hepatitis - HCV is responsible for almost all blood transfusion transmitted (non-A, non-B) hepatitis - About 300,000 in the United States may have contracted HCV from blood transfusions before screening tests were available - An estimated 4 million people in the U.S. infected with HCV - HCV is the major reason for liver transplants in the United States - In 2011, two protease inhibitors approved by FDA for HCV treatment: boceprevir and telaprevir - There is no vaccine against HCV - In 2019, major clinical trials of an experimental vaccine failed

Airborne Viral Diseases • Respiratory syncytial virus (RSV)

- Highly contagious and endemic worldwide - RSV is the common cause of two serious respiratory diseases—bronchiolitis and pneumonia - life-threatening to infants with preexisting lung or heart conditions - The symptoms of the infection are nonspecific (fever, runny nose, ear infection, and pharyngitis) - Outbreaks are a threat in pediatric wards and in nurseries - Frequent and careful hand washing decreases the transmission - Treatment is largely supportive, and oxygen therapy may be necessary in some cases - The antiviral drug ribavirin may be administered as an aerosol - There is currently no vaccine HOWEVER.......

Airborne Viral Diseases • Measles (Rubeola)

- Highly infectious; humans are the only reservoir - Transmission by respiratory droplets, exacerbated by: • Overcrowding • Low levels of herd immunity • Malnutrition • Poor medical care - Symptoms are cold-like, with the early development of Koplik's spots in the mouth followed by a red rash on the face that spreads to the extremities and most of the body

Sexually Transmitted Viral Infections • Genital Warts

- Human papillomaviruses (HPVs) are DNA viruses causing warts - Genital warts are fleshy growths of the genitals of men and women - There are > 100 types of HPV; about 1/3 are sexually transmitted - Infection rate is increasing; about one million new U.S. cases each year - Genital warts are highly contagious

Airborne Viral Diseases • Mumps

- Humans are the only natural hosts for the virus - Most commonly infects children under the age 15 - Infection of the parotid gland causes a large swelling on one or both sides of the face - Many children are asymptomatic - The virus can spread to the testes, ovaries, meninges, heart, and kidneys - Complications (rare) include sterility (males) and deafness

Botox is

- In addition to wrinkles, its effect on muscle cells makes Botox an approved treatment for other muscle-related conditions. Chronic migraines, overactive bladders, eyelid spasms, and strabismus or crossed eyes are FDA approved procedures. Some unconventional uses include reducing foot pain.

three varieties of anthrax

- Inhalation anthrax (woolsorter's disease) the most severe of the three, is an occupational hazard for humans exposed to contaminated dead animals and animal parts (e.g., tanners and sheep shearers), who are most likely to inhale spores - Cutaneous anthrax is acquired by contact with bacilli or spores via wool, hides, leather, or hair products - Gastrointestinal anthrax results from ingesting under-cooked meat contaminated with B. anthracis, leading to acute inflammation of the gastrointestinal tract, abdominal pain, vomiting of blood, and severe diarrhea • Cutaneous anthrax is acquired by contact with bacilli or spores

Contact Diseases and Bloodborne Viral Diseases • Rabies

- Jeanna Geise, 1st rabies survivor using innovative drug therapy in 2004 - Milwaukee Protocol • Drug-induced coma in combination with antiviral medications - 41 worldwide Milwaukee Protocol attempts • 5 survivors; Precious Reynolds, 8 year old California patient had the best recovery - 2012 CDC collaborative study with Peruvian Ministry of Health • Repeated exposures to rabid vampire bats may induce natural immunity in small percentage of individuals

Contact Diseases and Bloodborne Viral Diseases • Infectious Mononucleosis

- Most cases caused by Epstein-Barr virus (EBV), a DNA herpes virus - The virus infects and replicates in salivary glands - Transmitted by saliva and mucus during kissing, coughing, and sneezing - Symptoms are vague, and many people are asymptomatic • Early: malaise, headache, fatigue, and loss of appetite • Later: fever, sore throat, and swollen glands, particularly in the neck • Enlargement of the lymph nodes and spleen is a serious complication • You can live without a spleen. But because the spleen plays a crucial role in the body's ability to fight off bacteria, living without the organ makes you more likely to develop infections, especially dangerous ones such as Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae (Hib)

Poliomyelitis

- Most cases of polio are asymptomatic, but a small number result in paralysis - Replication in nerve cells causes paralytic poliomyelitis and limb deformities - Transmission is from person to person, direct fecal-oral contact, or by indirect contact with infectious saliva or contaminated water.

Gonorrhea, or the "clap," is caused by

- Neisseria gonorrhoeae, and like syphilis, humans are the only reservoir - Second only to chlamydia, infection rate highest in sexually active teens and young adults - May be transmitted via vaginal, oral, or anal sex - Pili adhesins allow firm attachment to mucosal surfaces - In males a purulent discharge from the penis and burning during urination is common - Asymptomatic males, but women, can carry and transmit gonorrhea for up to 10 years - Pelvic inflammatory disease (PID) occurs in about 50% of untreated females causing abdominal pain and possible sterility - Antibiotic resistance has jumped from less than 1% to over 13% of strains isolated in recent years

* Coronaviruses

- Severe acute respiratory syndrome (SARS)* - Middle East Respiratory Syndrome (MERS)* - COVID 19*

Preventing Future Outbreaks

- The ultimate goal for public health and food safety officials is not just stopping foodborne disease outbreaks once they occur, but preventing them from happening in the first place.

Hepatitis E virus

- Transmitted by the fecal-oral route - It is uncommon in the United States, but is endemic in Africa, Central America, India, and Asia

Hepatitis A

- Usually mild and self-limiting, with an abrupt onset - Unusual, as recovery is usually complete without chronic infection - Transmission is by the fecal-oral route, from contaminated food and drinking water - Approximately 50% of cases are subclinical - Good hand washing and sanitation is most effective at control - Diagnosis is based on detection of antibodies in the blood - No specific treatment, but a vaccine is available

Airborne Viral Diseases • Shingles (Herpes Zoster)

- Varicella-zoster, a DNA herpes virus, is the cause of chickenpox and shingles • Shingles typically occurs after the age of 45 to 50 in some who had chickenpox as a child - Humans are the only hosts for chickenpox and shingles - Transmission is by airborne droplets or by contact with the fluid in the vesicles that develop

Vaxchora

- Vaxchora is a vaccine indicated for active immunization against disease caused by Vibrio cholerae serogroup O1 in persons 2 through 64 years of age traveling to cholera-affected areas. (Jan. 1, 2021)

• Chlamydia

- is the most common STD *80% of females and 20% of male infections are asymptomatic - Males are subject to inflammation of the testes and infertility - Females have the most complications, including pelvic inflammatory disease, abnormal pregnancy, and infertility

What are the five infectious diseases (pathogens) that were studied to prevent the spread of HAIs?

1. Staphylococcus aureus (MRSA) 2. Escherichia coli 3. Pseudomonas aeruginosa 4. Clostridium difficile 5. Norovirus

Upper Respiratory Tract Infections Whooping cough is caused by

Bordetella pertussis - Humans are the only reservoir; there is a particular threat to children under age 4 - Transmission via contaminated droplets (talking, coughing, sneezing, and laughing) - Bacilli bind to ciliated epithelial cells in upper respiratory tract • Exotoxin damages ciliated cells which function to clear mucus from air passages • Triggers deep and rapid inspirations causing "whoop" - Is considered a reemerging disease - B. pertussis is endemic to the United States • Epidemics occur every 3-5 years

Diagnosing tuberculosis

Clinical signs and symptoms: weight loss, cough, fatigue, night sweats, low grade fever 2. X-ray examination 3. Positive skin test (indurated lesion 5 mm or greater) 4. demonstration of bacilli in sputum (presence of acid-fast bacilli on microscope examination of sputum) 5. Culture of M. tuberculosis

Food Intoxication (Food Poisoning):

Ingestion of bacterial toxins

Sexually Transmitted Infections Syphilis is caused by

Spirochete Treponema palladium • It frequently is found as a co-infection with other STDs, including HIV/AIDS • Humans are the only known reservoirs, there is no vaccine • Most U.S. cases are in the 20−29 year old age group; men who have sex with men accounted for about two thirds of cases • Spirochetes can pass across the placenta, resulting in congenital syphilis; stillbirths and deformities are possible • Syphilis progresses through a series of three stages: - The primary stage is marked by a painless chancre (sore) - The secondary stage is systemic, a rash dispersed on the body, but characteristically includes the palms and soles - A third of those untreated progress to tertiary syphilis, which can develop over the next 40 years (during which the cardiovascular and nervous systems, especially, show degenerative changes) • Neurosyphilis can result in paralysis (paresis), and insanity • Gummas, tumor like lesions, may develop

Airborne Bacterial Diseases

The major airborne bacterial diseases are divided into upper and lower respiratory tract infections

Lower Respiratory Tract Infections Tuberculosis (TB) is a leading cause of death worldwide

Tuberculosis (TB) • In the United States and other developed countries it is a reemerging disease • Evidence of TB dates back to 4,000 B.C. in Egypt • TB was once the leading cause of death in the United States and other countries • TB "sanatoria" treated TB with fresh air, bed rest, and good nutrition • TB declined as social conditions improved in the early 1900s • Antibiotics further pushed TB incidence back - Streptomycin, was discovered in the 1940s - Isoniazid, still widely used to treat TB, was introduced in 1952

Scarlet fever has a characteristic symptom

a "strawberry tongue." Caused by a Group A Streptococcus, it usually takes about 1 to 5 weeks after strep throat or scarlet fever for rheumatic fever to develop. - Pneumonia (lung infection) - Rheumatic fever (a heart disease) - Post-streptococcal glomerulonephritis (a kidney disease) - Arthritis (joint inflammation)

Pre-exposure prophylaxis (PrEP)

a pill containing antiretroviral drugs taken before someone is exposed to the virus to prevent HIV acquisition • Pre-exposure prophylaxis (PrEP) is for people who do not have HIV but are at risk of being exposed particularly through sex or injection drug use. • Two HIV medicines are approved by FDA for use as PrEP: Truvada and Descovy. PrEP is most effective when taken consistently each day. • PrEP effectiveness with consistent use reduces the risk of getting HIV from sex by about 99% and from injection drug use by at least 74%. • In Dec. 2021, the FDA approved the first injectable PrEP

Postpartum infections

also known as childbed fever and puerperal fever, are any bacterial infections of the female reproductive tract following childbirth or miscarriage.

Upper Respiratory Tract Infections Diphtheria is caused by

an exotoxin • Kills epithelial cells, which accumulate, forming a leathery pseudomembrane • Toxin diffuses into the bloodstream and may cause widespread damage, particularly to the heart • Death by suffocation may result • Diphtheria is rare in the United States and the rest of the developed world - It is a significant problem in the underdeveloped world - Immunization programs are needed to control the disease • Symptoms include extreme swelling of the lymph nodes resulting in a "bull neck" appearance

Post-exposure prophylaxis (PEP)

antiviral drugs used after possible HIV exposure but should be taken within 72 hours to prevent exposure • Post-exposure prophylaxis (PEP) requires taking HIV medicines within 72 hours (3 days) after a possible exposure to HIV to prevent infection. • PEP should be used only in emergency situations. PEP is not a substitute for regular use of other HIV prevention methods. • If you are prescribed PEP, you will take HIV medicines every day for 28 days.

Soilborne Diseases Tetanus (lockjaw)

is a noncommunicable disease, acquired by exposure to spores of Clostridium tetani

Foodborne and Waterborne Infection Salmonellosis

is caused by several species of salmonella • The symptoms include nausea, vomiting, abdominal cramps, diarrhea, and possibly fever. These are similar to the condition referred to as gastroenteritis. • Salmonella enteritidis infects eggs (the ovaries of healthy hens are infected) • Salmonella may also contaminate meats, seafood, and fresh fruits and vegetables • Iguanas, lizards, snakes, and turtles are carriers of a variety of salmonella species • Crows may harbor salmonella in their feces

Botulism

is caused by the deadly botulinum neurotoxin - Clostridium botulinum which is found in soil

Upper Respiratory Tract Infections Streptococcusis a

large genus of G+ cocci, the most virulent is S. Pyogenes • infections range from mild to deadly • Streptococci reside in the human nose and throat • Transmitted by respiratory droplets or contact with sores or wounds • Streptococcal pharyngitis (tonsillitis) is common in children 5-15 • Long-term complications from repeated childhood strep infections - Glomerulonephritis, a kidney disease - Rheumatic fever, a condition involving the heart and joints • Streptococcal toxic shock syndrome and necrotizing fasciitis are caused by invasive strep that can cause life-threatening infections

Salmonella typhi causes

typhoid fever • Typhoid occurs primarily in less-developed countries • Infection is from fecally contaminated food or hands • Transmission by flies and fomites is also common • The organism invades the cells lining the small intestines, causing ulcers and bloody stools, fever, and possibly delirium

Airborne Viral Diseases • MMR controversial vaccine

• Andrew Wakefield - Lead researcher of 1998 The Lancet report suggesting MMR vaccine caused autism - The Lancet report was retracted in 2012 - Wakefield found guilty of unethical medical practice and scientific misconduct

Soilborne Diseases Anthrax is caused by

• Bacillus anthracis • Anthrax is primarily found in grazing animals, mostly sheep and cattle; infection most prevalent in agricultural areas • Anthrax is a likely candidate for use in biowarfare, because these spores can be readily spread by missiles and bombs Antibiotics are effective against all forms of anthrax, but early intervention is necessary; vaccine is available for high risk workers • There are three varieties of anthrax

Foodborne and Waterborne Infection Campylobacteriosis caused by

• Campylobacter jejuni - The most frequent cause of bacterial diarrhea in the United States - Poultry, cattle, and unpasteurized milk have been identified as potential sources - Many isolates are antibiotic resistant - Campylobacter infection is the most commonly identified cause of Guillan-Barré syndrome.

Pseudomembranous colitis is caused

• Clostridium difficile • Transmission is via fecal-oral route - A major cause of nosocomial infection or Healthcare-Associated Infections (HAIs) - Associated with patients on antibiotics - Depletion of the normal flora by the use of antibiotics may allow C. difficile to "grow out," usually causing mild to severe diarrhea

Airborne Viral Diseases The cold and other respiratory viruses have a seasonal incidence

• Cold virus can also be spread by hands and fomites (e.g. doorknobs, faucets) • Sneeze and cough etiquette - Surfactants • Three-ply tissues

Airborne Viral Diseases • Common Cold

• Common Cold • About half of all colds are caused by two RNA viruses: - Rhinoviruses - Coronaviruses • Symptoms are sneezing, coughing, sore throat, stiffness and malaise • Within some viral groups there may be over 100 different strains • Transmission is by droplets and fomites (hands, doorknobs, etc.) • Most cold viruses possess mechanisms for attachment to nasal passages • Diagnosis of a cold is symptom-based • The illness is generally mild and self-limiting

Enterotoxigenic

• E. coli is the most common cause of traveler's diarrhea - E. coli is easy to culture and detect; its presence is used as an indicator of fecal contamination

Viral and Prion Diseases Gastroenteritis

• Gastroenteritis is characterized by stomach and abdominal pain, diarrhea, vomiting, and abdominal cramps • Rotaviruses - About 200,000 ER visits a year in the U.S. • Noroviruses (Norwalk and Norwalk-like viruses) • ID is < 10 viral particles • Viruses can persist in the environment • Viruses continue to be shed after recovery • Outbreaks associated with cruise ships, food service workers, hospitals, etc. • There are many different strains

Arthropodborne Diseases Plague(Black Death), is caused by the

• G− bacillus, Yersinia pestis, one of the most virulent bacteria known - From 1347 to 1351, one-third of the population of Medieval Europe (about 25 million people), died of the Black Death - ID is a single bacillus - Y. pestis was used as a weapon of biological warfare by the Japanese army in World War II - Plague is a reemerging infection because of increased incidence globally

Arthropodborne Diseases Ehrlichiosisis caused by

• G− intracellular bacillus - Emerging tickborne zoonosis, first reported in humans in 1986 - Symptoms are fever, headache, general malaise, and possibly a rash - Primarily along the Atlantic coast and in the south-central United States - There are two forms of the disease; both respond well to antibiotics • Human monocytic ehrlichiosis is caused by Ehrlichia chaffeensis - The lone star tick is the vector • Human anaplasmosis (formerly known as human granulocytic ehrlichiosis) is caused by Anaplasma phagocytophilum - Vectors are the dog tick and deer tick

Contact Diseases Peptic Ulcers are caused by

• Helicobacter pylori Produce the enzyme urease, which breaks down urea into ammonia and CO2, ammonia neutralizes stomach acid, allowing the bacteria to survive - Transmission is via person-to-person contact - Infection (and ulcers) can be cured with antibiotics - Infection is also associated with gastric cancer - ~20% of the population under age 40 and 50% over 60 are infected in the United States; only ~10% ever get ulcers

Airborne Viral Diseases • Early signs of chickenpox are fever, headache, aches and pains, followed in a few days by an itchy rash with fluid-filled vesicles appearing on the scalp, face, trunk, and extremities

• In 1995, the FDA approved a live, attenuated chickenpox vaccine that dramatically reduced chickenpox deaths • In 2006, the CDC recommended a booster shot for children ages four to six • 2010, MMRV available to vaccinate children (measles, mumps, rubella, varicella) • The disease exists worldwide, and nearly all unvaccinated children are infected during their early years • Like measles, chickenpox can cross the placenta and harm the fetus

Influenza Strains • 3 types/categories of Influenza viruses

• Influenza A - Causes epidemics and pandemics - Infects animals, birds, humans etc. • Influenza B - Less severe, causes epidemics, no animal reservoir • Influenza C - Causes mild respiratory illness in humans

Airborne Viral Diseases • Measles is usually mild and self-limiting, but one in 500 children develops potentially fatal complications, including pneumonia, ear infections, brain damage, and seizures

• It is a significant cause of death in developing countries • Immunity from infection is lifelong • Recent outbreaks have occurred in the United States; the common denominators were no measles vaccine frequently due to religious beliefs, overseas exposure, and home schooling

Listeriosis is caused by

• Listeria monocytogenes • This organism is distributed worldwide • Contaminates cold cuts, hot dogs, soft cheeses, etc. • Grows under refrigeration • Listeriosis is usually mild in healthy adults and children - Infants, the elderly, the immunocompromised, and pregnant women are at high risk - Fetuses and newborns may become acutely ill from their infected mothers - Antibiotics must be given promptly to prevent infection and miscarriage of a fetus

Airborne Viral Diseases • Middle East Respiratory Syndrome (MERS)

• Middle East Respiratory Syndrome (MERS) It was first reported in Saudi Arabia in 2012 and has since spread to several other countries, including the United States.

Gastroenteritis

• Noroviruses (Norwalk and Norwalk-like viruses) ID is less than (<) 10 viral particles Infective dose (ID) is the minimal number of microbes necessary for infection. More virulent organisms have smaller IDs than less virulent organisms Bacteria that causes gastroenteritis: - E. coli - Salmonella - Campylobacter - campylobacteriosis - Shigella - shigellosis

Preventing Perinatal Transmission of HIV

• Perinatal transmission of HIV (MTCT)is when HIV is passed from a woman with HIV to her child during pregnancy, childbirth, or breastfeeding. • The use of HIV medicines antiretrovirals have helped lower the rate of perinatal transmission of HIV to 1% or less • A scheduled cesarean delivery can reduce the risk of perinatal transmission of HIV in women who have a high viral load or an unknown viral load near the time of delivery. • Woman with HIV can still pass HIV to her baby while breastfeeding so infant formula should be substituted.

Poliomyelitis

• Poliomyelitis (polio or infantile paralysis) - May be eradicated soon; humans are the only reservoir for this RNA virus - The first polio virus vaccine, the Salk vaccine, was introduced in the 1950s, followed by the Sabin vaccine • The Salk vaccine uses killed viruses of the three polio strains • The Sabin vaccine is composed of live, attenuated viruses Inactivated poliovirus vaccine (IPV) IPV is the only polio vaccine that has been used in the United States since 2000. • It is given by shot in the leg or arm, depending on the patient's age. • Children should get four doses total, with one dose at each of the following ages: • 2 months old, • 4 months old, • 6 through 18 months old, and • 4 through 6 years old.

Arthropodborne Diseases Rickettsiae

• Rickettsiae are obligate intracellular parasites of eucaryotes • They are carried by arthropods (except for Q fever) - Including ticks, body lice, and fleas • Symptoms generally include a rash, which varies depending on the particular rickettsial infection, and flulike symptoms • Antibiotics can be effective • Methods of control are directed at minimizing the contact between the vector and humans

Arthropodborne Diseases Rocky Mountain Spotted Fever

• Rocky Mountain Spotted Fever is found in almost all of the 50 states - A tick feeding on a human or other mammalian host transfers the causative organism, Rickettsia rickettsii - It is the most severe tickborne rickettsial disease in the United States - Up to 20% of those infected die without treatment - The elderly are particularly vulnerable • Endemic (or murine) typhus, is caused by Rickettsia typhi and is transmitted by fleas found on mice and rats; rodent control is key to breaking the disease cycle • Epidemic typhus is caused by Rickettsia prowazekii and is transmitted by the human body louse; the human is the only reservoir. As the louse feeds it defecates; scratching inoculates the rickettsia into the bite - Overcrowded and unsanitary conditions increase infection

Arthropodborne Diseases • Endemic and epidemic relapsing fever

• Spirochetes undergo antigenic change (basis for the name relapsing fever) • Relapses occur approximately every two to four days (with one to four relapses) • The endemic form is transmitted by ticks; found in many areas of world • The epidemic form is transmitted from person-to-person by body lice that cause itching, it is more serious, with 30% to 70% mortality if untreated - Scratching crushes the spirochete-infected lice into the skin - Found in eastern and central Africa, China, and the Peruvian Andes - Is associated with overcrowding (refugee camps), war, poverty, etc. - The best forms of prevention are the delousing of people and clothing and improved hygienic conditions

Contact Diseases

• Staphylococci are normal flora of the skin, mouth, nose, and throat • Unless the skin barrier is broken, staphylococci are normally harmless • Cause of purulent (pus containing) skin lesions, pimples, boils, carbuncles • Can progress into systemic (bloodborne) infections • Staphylococcus aureus is the most virulent of the staph - Methicillin-resistant Staphylococcus aureus(MRSA) are the leading cause of nosocomial infections in the United States - Impetigo is a superficial blister that produces an oozing highly infectious yellow discharge - Scalded skin syndrome causes blistering skin due to an exfoliative toxin - Toxic shock syndrome from S. aureus strains that secrete the TSS-exotoxin, eliciting high fever, nausea, vomiting, peeling of the skin (particularly on the palms and the soles), and a dangerous drop in blood pressure that leads to life-threatening shock • Community-acquired MRSA (CA-MRSA) infections • Associated with - Athletic facilities • Highly physical sports - Dormitories - Military barracks - Correctional facilities - Day care centers

The Basics of HIV Prevention

• The human immunodeficiency virus is the virus that causes HIV infection. HIV causes acquired immunodeficiency syndrome (AIDS) • HIV is spread through contact with the blood, semen, pre-seminal fluid, rectal fluids, vaginal fluids, or breast milk of a person with HIV. In the U.S., HIV is spread mainly by having anal or vaginal sex or sharing injection drug equipment with a person who has HIV. • Antiretroviral therapy (ART) is the use of HIV medicines to treat HIV infection. People on ART take a combination of HIV medicines every day. • ART cannot cure HIV infection, but HIV medicines help people with HIV live longer, healthier lives. HIV medicines can also reduce the risk of HIV transmission.

Soilborne Diseases

• The number of tetanus cases in the United States is about 50 to 100 per year, absent or inadequate immunization leads to higher incidence in underdeveloped countries • Neonatal tetanus is common in the first month of life - The disease is prevalent in poor-nations when an infant is delivered under unsanitary conditions to a nonimmunized mother (the umbilical cord may be contaminated when cut) - Prevention is centered on vaccination of all women of childbearing age, improved delivery and post-delivery practices, and education

Airborne Viral Diseases Shingles Vaccine

• The recombinant zoster vaccine (Shingrix) is recommended to prevent shingles in adults 50 and older. In addition, it will prevent postherpetic neuralgia (PHN), the most common complication from shingles. • Also, Shingrix is recommended for adults 19 years and older who have weakened immune systems because of disease or therapy. • You can get the 2 dose Shingrix vaccine by your physician or pharmacist.

Poliomyelitis Oral poliovirus vaccine (OPV)

• This vaccine is no longer licensed or available in the United States. • It is still used in some parts of the world. • Children receive doses of the vaccine by drops in the mouth.

Airborne Viral Diseases • HPS virus is carried by rodents (e.g., deer mice and cotton rats)

• Transmission is due to exposure to dried and aerosolized feces, saliva, or urine from infected rodents • The virus is not transmitted from human to human • Prevention is based on avoiding contact with rodents and their excreta • Diagnosis of hantavirus disease is difficult, because the early flulike signs are nonspecific • Definitive diagnosis requires laboratory procedures

Leprosy (Hansen's disease)

• Transmission via extended skin contact and droplets • The incubation time is long; children are most susceptible • Disease characterized by a variety of physical manifestations - Tumorlike skin lesions (lepromas) - Neurological damage to cooler areas of the body, such as the hands, feet, face, and earlobes - Lost ability to perceive pain in the fingers and toes, results in accidental burns and serious deformities - Antibiotics are available to arrest the disease

Transmission of Influenza

• Transmitted through droplets/aerosol - Sneezing, coughing • Fomites play a secondary role • Conditions of cooler temperatures and low humidity favor transmission • Crowding, close intermingling favors transmission - e.g. nursing homes, classrooms, army barracks

Airborne Viral Diseases

• Usually spread through respiratory droplets from an infected person to a susceptible person. - Respiratory syncytial virus (RSV) - Common cold - Influenza - Measles (rubeola) - Mumps - German measles (rubella) - Chickenpox (varicella) and shingles - Smallpox (variola) - Hantavirus pulmonary syndrome

Mumps Prevention

• Wash hands frequently and efficiently. When unable to wash with soap and water, use an alcohol-based hand sanitizer. • Cover your mouth with a tissue when coughing or sneezing; use your upper sleeve to cover your cough, not your hand. • Avoid sharing food, drinks and items such as eating utensils, cigarettes or vaping devices. • Avoid participating in any activities that may result in saliva exposure.

Treatment: What does Xofluza do that Tamiflu doesn't?

• Xofluza requires only a single dose if taken within 48 hours of the onset of symptoms. Xofluza can reduce the amount of time a person is sick by more than a day. • Tamiflu requires patients to take two doses a day for about five days. Also, it can be given to children under 12 and its generic version is typically much cheaper than Xofluza.

Pre-exposure Rabies Vaccine If you are at higher risk of exposure to the rabies virus:

• You should receive 2 doses of rabies vaccine given on days 0 and 7. • Depending on your level of risk, you may be advised to have one or more blood tests or receive a booster dose within 3 years after the first 2 doses.

Foodborne infection:

• bacteria multiply in the intestinal tract, secrete an enterotoxin, and may invade cells of the intestinal tract - Enterotoxins cause symptoms of nausea, vomiting, diarrhea, and possibly bloody stools

Cholera

• intoxication is caused by the exotoxin secreted Vibrio cholera - Consuming fecally-contaminated water or food (including raw shellfish) causes infection • Pandemics documented over the centuries • Characteristic of cholera is a voluminous rice-water diarrhea - Rehydration must be instituted quickly to avert death • Oral rehydration therapy can save lives

Congenital syphilis (CS) is

• is a disease that occurs when a mother with syphilis passes the infection on to her baby during pregnancy. • The rates of congenital syphilis in the U.S. are the highest in 25 years. • CS can cause miscarriage, stillbirth, prematurity, low birth weight, or death shortly after birth.

Soilborne diseases Tetanospasmin

• is a neurotoxin; the second most deadly bacterial toxin - Tetanus bacilli are ubiquitous and are abundant in soil, manure, and dust - Spores germinate and bacilli multiply in deep, anaerobic, puncture wounds (from gunshot wounds, animal bites, etc.) - Tetanus prevents muscle relaxation, resulting in uncontrollable contraction Opisthotonos is extreme contractions in the back and rib muscles that cause the body to arch severely - Death occurs by suffocation

Upper Respiratory Tract Infections Meningitis

• is an inflammation of the meninges • Early diagnosis is essential; cold-like symptoms progress quickly to fever, possibly delirium, and stiffness in the neck and back • The two most common causes are: - Neisseria meningitides - Meningococcemia, responds to antibiotic therapy • A vaccine is available Meningococcal B • College students living in dormitories appear to be particularly susceptible to meningococcal meningitis - Haemophilus influenzae type b (Hib) - Hib meningitis occurs primarily in children under age five • Incidence has dropped with the Hib vaccine in early 1990s • About 10% of healthy people carry Hib in nose and throat

Lower Respiratory Tract Infections Legionnaire's disease(legionellosis) is caused by

• is caused by Legionella pneumophila - Transmission is by inhalation of aerosols that come from a water source contaminated withL. pneumophila - People middle-aged and older, smokers, and those with chronic lung disease are the most susceptible - Symptoms are fever, muscle pain, cough, and pneumonia (all typical of other respiratory infections) - Death is usually by shock and kidney failure - Prevention involves eliminating sources of warm, stagnant waters in which there is the potential for aerosolization

Food Intoxication Staphylococcal food poisoning

• is caused by Staphylococcus aureus • Most common type of food poisoning - Found in human nasal passages - Heat stable enterotoxin • Symptoms include abdominal cramps, nausea, vomiting, and diarrhea • Symptoms appear within a few hours and can be very severe

Shigellosis

• is caused by species of Shigella • Symptoms are gastroenteritis, and possibly dysentery • Severe diarrhea containing blood and mucus • Resultant dehydration can be deadly • Sources: eggs, shellfish, dairy products, vegetables, water • Transmission via the fecal-oral route, infectious dose (ID) is very low • Treatment involves oral or IV rehydration and possibly antibiotics • About one million annual deaths in developing countries • Day care centers are prone to outbreaks

Antibiotic therapy for TB infection

• isoniazid for 6 months is very effective • Active TB disease requires: Taking a combination of antibiotics for 6 to 9 months • Supportive measures of adequate rest, a good diet, etc. • Five antibiotics are particularly effective against the tubercle bacilli: isoniazid, ethambutol, rifampin, streptomycin, and pyrazinamide • Toxicity and antibiotic resistance must be considered

Arthropodborne Diseases Plague is azoonosis;

• many mammals, primarily rodents (e.g., gophers, squirrels, mice, rats, etc.), serve as reservoirs - Infection frequently results from an infected flea bite - Sporadic cases in Southwest United States due to prairie dogs or rodents • In bubonic plague, the bacilli localize in the lymph nodes of groin, armpits, and neck, and cause the nodes to swell (buboes) - The bacilli can spread to the bloodstream, liver, lungs, and other sites, hemorrhages under the skin turns black - Not normally infectious, mortality over 50%

Lyme Disease Tickborne zoonosis

• present throughout the United States, esp. Northeast, upper Midwest, and Pacific Coast (first found in Old Lyme, Connecticut in 1975) • Also found in Europe, Australia, the former USSR, China, and Japan • Symptoms are vague, flu-like, with fever, headache, muscle and joint pain • Some individuals have a spreading "bull's-eye" skin rash • Lyme disease can cause symptoms of arthritis and numbness which appear years after infection • Diagnosis includes history of tick exposure, symptoms, and blood tests positive for the presence of the antibodies to the spirochetes • Early treatment with appropriate antibiotics usually leads to quick recovery • No vaccine is available, but a promising vaccine is under development • Lyme disease has a complex two-year cycle; humans are the final hosts

Soilborne Diseases Leptospirosis, orswamp fever, is caused by the

• the spirochete Leptospira interrogans • Reservoirs are various animals (e.g., dogs, rats, etc.), rats appear to be the most significant source of disease • Transmission is spread via urine; spirochetes penetrate the human skin, enter the bloodstream, and rapidly invade virtually all organs • May be transmitted by ingesting water contaminated with rat urine • It is not transmitted from human to human • Leptospirosis can be a serious and potentially fatal disease, with symptoms including jaundice, fever, headache, nausea, and chills • Leptospirosis is most common in tropical countries

Bacille Calmette-Guérin (BCG) is a

• vaccine for tuberculosis (TB) disease. This vaccine is not widely used in the United States, but it is often given to infants and small children in other countries where TB is common. BCG does not always protect people from getting TB.

Arthropodborne Diseases Pneumonic plague occurs

• when those with the bubonic form develop pneumonia and transmit the bacteria to others by coughing and through saliva - Approaches 100% fatality without early treatment - Vaccine is protective for only a few months and is only given to persons at high risk • Septicemic plague results from the spread of bacteria from the lungs to other parts of the body - Acquired by contact of contaminated hands, food, or objects with the mucous membranes of the nose or throat - Is considered to be 100% fatal