Infections, such as lower respiratory tract infections, malaria, HIV, and tuberculosis (TB), are responsible for a significant number of deaths worldwide.¹ Infection occurs when a pathogen (a microorganism that causes disease) invades the body, begins to multiply, and produces disease, usually causing harm to the host. The signs and symptoms of infection are a result of specific pathogen activity, which triggers inflammation and other immune responses.²

Infections can be divided into localized, disseminated, and systemic disease. A localized infection is limited to a small area. A disseminated infection has spread to areas of the body beyond the initial site of infection. Systemic infections have spread extensively throughout the body, often via the blood.

eTABLE 15-1

CENTERS FOR DISEASE CONTROL AND PREVENTION (CDC) GUIDELINES FOR ISOLATION PRECAUTIONS

Standard Precautions	Transmission-Based Precautions
Standard Precautions	Airborne	Droplet	Contact
When to Use
All patients	Use in addition to standard precautions for patients known to be or suspected of being infected with microorganisms transmitted by airborne droplet (e.g., measles, varicella, tuberculosis).	Use in addition to standard precautions for patients known to be or suspected of being infected with microorganisms transmitted by droplets (e.g., Haemophilus influenzae, Neisseria meningitidis, Streptococcus pneumoniae, Mycoplasma pneumoniae).	Use in addition to standard precautions for specified patients known to be or suspected of being infected with epidemiologically important microorganisms that can be transmitted by direct contact with patient (e.g., enteric pathogens, multidrug-resistant bacteria, Staphylococcus aureus, Clostridium difficile, herpes simplex) or by direct contact with environmental surface or patient care items in the patient’s environment.
Handwashing
Wash hands (1) after touching blood, body fluids, secretions, excretions, and contaminated items, regardless of whether gloves are worn; (2) immediately after gloves are removed; and (3) between patient contacts.	Same as standard precautions	Same as standard precautions	Same as standard precautions
Gloves
Wear gloves when touching blood, body fluids, secretions, excretions, and contaminated items; use gloves when touching mucous membranes and nonintact skin; remove gloves promptly after use, before touching noncontaminated items or environmental surfaces, or going to another patient.	Same as standard precautions	Same as standard precautions	In addition to use described in standard precautions, wear gloves when in the room and providing direct patient care or having hand contact with potentially contaminated surfaces or items in patient’s environment.
Mask, Eye Protection, Face Shield (always provide full face coverage when there is a risk)
Wear mask and eye protection or face shield to protect mucous membranes of eyes, nose, and mouth during patient care procedures likely to generate splashes or sprays of blood, body fluids, secretions, or excretions (especially suctioning, endotracheal intubation).	In addition to standard precautions, wear respiratory protection when entering room of patient known to have or suspected of having tuberculosis.	In addition to standard precautions, wear a mask when working within 3 ft of patient.	Same as standard precautions
Gown
Wear clean gown to protect skin and prevent soiling of clothing during patient care procedures likely to generate splashes or sprays of blood, body fluids, secretions, or excretions or likely to cause soiling of clothing; remove gown promptly when tasks are completed; wash hands.	Same as standard precautions	Same as standard precautions	Wear clean gown if substantial contact is anticipated with patient, surfaces, or items in environment; wear gown if patient is incontinent or has diarrhea, an ileostomy, a colostomy, or uncontained wound drainage; remove gown carefully when tasks are completed; wash hands.
Linen and Used Equipment
Handle, transport, and process used linen and equipment in manner that prevents skin and mucous membrane exposure, contamination of clothing, and environmental soiling.	Same as standard precautions	Same as standard precautions	Same as standard precautions
Needles and Other Sharps
Do not recap, bend, break, or hand-manipulate used needles; place used sharps in puncture-resistant container immediately after use; if recapping is required, use a one-handed scoop technique only; use safety features (such as needle retraction and needleless systems) when available.	Same as standard precautions	Same as standard precautions	Same as standard precautions
Patient Transport
	Limit movement and transport of patient from room to essential purposes only; if transport or movement is necessary, minimize patient dispersal of droplet nuclei by placing surgical mask on patient, if possible.	Limit movement and transport of patient from room to essential purposes only; if transport or movement is necessary, minimize patient dispersal of droplet nuclei by masking patient, if possible.	Limit movement and transport of patient from room to essential purposes only; if transport is necessary, ensure that precautions are maintained to minimize contamination of environmental surfaces or equipment.

From www.cdc.gov/ncidod/dhqp/gl_isolation.html.

eTABLE 15-2

TREATMENT OF COMMON OPPORTUNISTIC DISEASES ASSOCIATED WITH HIV INFECTION

Organism/Disease	Clinical Manifestations	Prophylaxis^* and Treatment^†
Candida albicans	Thrush (see Fig. 15-5), esophagitis, vaginitis; whitish yellow patches in mouth, esophagus, GI tract, vagina	Treatment: fluconazole (Diflucan), clotrimazole (Lotrimin), nystatin (Mycostatin), itraconazole (Sporanox); if fluconazole refractory, amphotericin B (Fungizone)2° Prophylaxis (only if subsequent episodes are frequent or severe recurrences): fluconazole (Diflucan), itraconazole (Sporanox)
Coccidioides immitis	Pneumonia/fever, weight loss, cough	Treatment: amphotericin B (Fungizone), fluconazole (Diflucan), itraconazole (Sporanox)2° Prophylaxis (to prevent recurrence of documented disease): fluconazole (Diflucan), amphotericin B (Fungizone), itraconazole (Sporanox)
CNS lymphoma	Cognitive dysfunction, motor impairment, aphasia, seizures, personality changes, headache	Treatment: radiation, chemotherapy
Cryptococcus neoformans	Meningitis, cognitive impairment, motor dysfunction, fever, seizures, headache	Treatment: amphotericin B (Fungizone), fluconazole (Diflucan), itraconazole (Sporanox)2° Prophylaxis (to prevent recurrence of documented disease): fluconazole (Diflucan), amphotericin B (Fungizone), itraconazole (Sporanox)
Cryptosporidium muris	Gastroenteritis, diarrhea, abdominal pain, weight loss	Treatment: initiation of ART is the primary treatment in persons with CD4+ T-cell count <100 cells/µL, antidiarrheals, nitazoxanide (Alinia), paromomycin (Humatin)
Cytomegalovirus (CMV)	Retinitis: retinal lesions, blurred vision, loss of visionEsophagitis/stomatitis: difficulty swallowing; colitis/gastritis: bloody diarrhea, pain, weight lossPneumonitis: respiratory symptomsNeurologic disease: CNS manifestations	Treatment: ganciclovir (Cytovene), foscarnet (Foscavir), cidofovir (Vistide), valganciclovir (Valcyte)2° Prophylaxis (to prevent recurrence of documented disease): ganciclovir (Cytovene), foscarnet (Foscavir), cidofovir (Vistide), valganciclovir (Valcyte)
Hepatitis B virus (HBV)	Jaundice, fatigue, abdominal pain, loss of appetite, nausea, vomiting, joint pain; 30% may have no signs or symptoms	1° Prevention: hepatitis B vaccine series; screen and vaccinate those with no evidence of previous HBV infection; encourage for IDU, sexually active MSM, sexual partners or household contacts of HBV-infected individuals, and those with hepatitis C virus; hepatitis A vaccine series should be given to prevent additive effects and advanced liver damage; screen and vaccinate those without evidence of previous HAV infectionTreatment: tenofovir (Viread), emtrictabine (Emtriva), adefovir dipivoxil (Hepsera), α-interferon, lamivudine (Epivir), entecavir (Baraclude)Monotherapy is not recommended; must treat with at least two active agents
Hepatitis C virus (HCV)	Jaundice, fatigue, abdominal pain, loss of appetite, nausea, vomiting, dark urine; 80% may have no signs or symptoms	Prophylaxis: none for HCV. Hepatitis A and B vaccine series should be given to prevent additive affects and advanced liver damage; screen and vaccinate those without evidence of previous HAV/HBV infectionTreatment: peginterferon α-2a (Pegasys), ribavirin (Copegus). Treatment with HCV protease inhibitors is currently under investigation
Herpes simplex	HSV1 (type 1): orolabial and mucocutaneous vesicular and ulcerative lesions; keratitis: visual disturbances; encephalitis: CNS manifestationsHSV2 (type 2): genital and perianal vesicular and ulcerative lesions	Treatment: acyclovir (Zovirax), famciclovir (Famvir), valacyclovir (Valtrex), foscarnet (Foscavir), cidofovir (Vistide)2° Prophylaxis (only if subsequent episodes are frequent or severe): acyclovir (Zovirax), famciclovir (Famvir), valacyclovir (Valtrex)
Histoplasma capsulatum	Pneumonia: fever, cough, weight lossMeningitis: CNS manifestations; disseminated disease	Treatment: amphotericin B (Fungizone), itraconazole (Sporanox), fluconazole (Diflucan)2° Prophylaxis (to prevent recurrence of documented disease): itraconazole (Sporanox), amphotericin B (Fungizone)
Influenza virus	Fever (usually high), headache, extreme tiredness, dry cough, sore throat, runny or stuffy nose, muscle aches; nausea, vomiting, and diarrhea can occur	1° Prevention: inactivated trivalent influenza virus vaccine; provide annually before influenza virus season; revaccinate if initial vaccine was given when CD4⁺ T cell count <200/µLTreatment: supportive therapy
JC papovavirus	Progressive multifocal leukoencephalopathy (PML), CNS manifestations, mental and motor declines	Treatment: supportive therapy
Kaposi sarcoma (KS) caused by human herpesvirus 8 (HHV8)	Vascular lesions on the skin (see Fig. 15-6), mucous membranes, and viscera with wide range of presentation: firm, flat, raised, or nodular; pinpoint to several centimeters in size; hyperpigmented, multicentric; can cause lymphedema and disfigurement, particularly when confluent; not usually serious unless it occurs in the respiratory or gastrointestinal systems	Treatment (dependent on severity of lesions): initiation of ART should be the first priority; cancer chemotherapy, α-interferon, local radiation; cryotherapy for skin lesions
Mycobacterium avium complex (MAC)	Gastroenteritis, diarrhea, weight loss	1° Prophylaxis: initiate when CD4⁺ T cells <50/µL; rule out disseminated disease or tuberculosis: azithromycin (Zithromax), clarithromycin (Biaxin), or rifabutin (Mycobutin). Prophylaxis may be stopped when CD4⁺ T-cell count of >100/µL is documented for 6-12 mo; restart if CD4⁺ T-cell count falls to <50/µLTreatment: clarithromycin (Biaxin), ethambutol (Myambutol), rifabutin (Mycobutin), azithromycin (Zithromax), ciprofloxacin (Cipro), levofloxacin (Levaquin), amikacin (Amikin)
Mycobacterium tuberculosis	Respiratory and disseminated disease; productive cough, fever, night sweats, weight loss	1° Prophylaxis: initiate if TST testing is ≥0.5 mm or reactive result on interferon gamma release assay, after high-risk exposure, or if prior positive TB testing without treatment: isoniazid (INH) + pyridoxine for 9 mo; consider directly observed therapy. Rule out active disease, extrapulmonary disease, or drug-resistant strain, all of which require multidrug therapyTreatment: isoniazid (INH), rifampin (Rifadin), rifabutin (Mycobutin), pyrazinamide, ethambutol (Myambutol)
Pneumocystis jiroveci pneumonia (PCP)	Pneumonia, nonproductive cough, hypoxemia, progressive shortness of breath, fever, night sweats, fatigue	1° Prophylaxis: initiate when CD4⁺ T cells <200/µL: trimethoprim/sulfamethoxazole (TMP/SMX), dapsone, dapsone with pyrimethamine + folinic acid, aerosolized pentamidine, atovaquone. Side effects of TMP/SMX and dapsone (especially rash, fever, and anemia) are common and may limit useTreatment: trimethoprim/sulfamethoxazole (Bactrim), pentamidine (NebuPent), dapsone + trimethoprim, clindamycin (Cleocin) + primaquine, atovaquone (Mepron); with hypoxia, use corticosteroids
Toxoplasma gondii	Encephalitis, cognitive dysfunction, motor impairment, fever, altered mental status, headache, seizures, sensory abnormalities	1° Prophylaxis: initiate with positive toxoplasmosis IgG titer when CD4⁺ T cells <100/µL: trimethoprim/sulfamethoxazole (TMP/SMX) or dapsone with pyrimethamine + folinic acid or atovaquone ± pyrimethamine + folinic acidTreatment: pyrimethamine + folinic acid + sulfadiazine, clindamycin (Cleocin), azithromycin (Zithromax), atovaquone (Mepron)
Varicella-zoster virus (VZV)	Shingles: erythematous maculopapular rash along dermatomal planes, pain, pruritisOcular: progressive outer retinal necrosis (PORN)	1° Prophylaxis: varicella-zoster immune globulin (VZIG) administered only after significant exposure to chickenpox or shingles for patients with no history of disease or negative VZV antibody testTreatment: acyclovir (Zovirax), famciclovir (Famvir), valacyclovir (Valtrex)

ART, Antiretroviral therapy; CNS, central nervous system; GI, gastrointestinal; IDU, injection drug use; IgG, immunoglobulin G; MSM, men who have sex with men; 1°, primary; 2°, secondary; TST, tuberculin skin test.

^*If available. In most cases, effective antiretroviral therapy is the best prevention for all opportunistic diseases.

^†In most cases, adequate antiretroviral therapy is the best treatment for all opportunistic diseases.

Sources: Centers for Disease Control and Prevention (CDC): Guidelines for prevention and treatment of opportunistic infections in HIV-infected adults and adolescents—April 10, 2009. Available at http://aidsinfo.nih.gov.

eTABLE 15-3

DRUG THERAPY Side Effects of Antiretroviral Agents Used in Human Immunodeficiency Virus (HIV) Infection *

Current recommendations for therapy require combinations of three or more of these drugs.
Drug Classification and Mechanism of Action	Examples	Side Effects
Entry Inhibitors
Prevent binding of HIV to cells, thus preventing entry of HIV into cells where replication would occur	enfuvirtide (Fuzeon)	Injection site reactions (ISRs), fatigue, nausea, diarrhea, insomnia, peripheral neuropathy, hypersensitivity reaction, pneumonia
	maraviroc (Selzentry)	Cough, fever, upper respiratory infection, rash, myalgias, dizziness
Reverse Transcriptase Inhibitors
*Nucleoside Reverse Transcriptase Inhibitors (NRTIs)*		Side effects common to NRTIs: lactic acidosis with hepatic steatosis is a rare but potentially life-threatening problem; lipodystrophy, especially lipoatrophy and mitochondrial toxicity
Insert a piece of DNA into the developing HIV DNA chain, blocking further development of the chain and leaving the production of the new strand of HIV DNA incomplete	zidovudine (AZT, ZDV, Retrovir)	Nausea, vomiting, anemia, leukopenia, fatigue, headache, insomnia, pancreatitis
	didanosine (ddI, Videx, Videx-EC [time-released])	Nausea, diarrhea, peripheral neuropathy (dose related and reversible), pancreatitis
	stavudine (d4T, Zerit)	Peripheral neuropathy, nausea, pancreatitis
	lamivudine (3TC, Epivir)	Minimal toxicities, nausea, nasal congestion
	abacavir (Ziagen)	Nausea; hypersensitivity reaction, including fever, nausea, vomiting, diarrhea, lethargy, malaise, sore throat, shortness of breath, cough, rash; may produce life-threatening event if hypersensitivity is rechallenged
	emtricitabine (FTC, Emtriva)	Headache, diarrhea, nausea, rash, skin discoloration
	Combivir (lamivudine and zidovudine combination)	Combines side effects of lamivudine and zidovudine
	Trizivir (lamivudine, zidovudine, and abacavir combination)	Combines side effects of lamivudine, zidovudine, and abacavir
	Epizicom (lamivudine and abacavir combination)	Combines side effects of lamivudine and abacavir
*Nucleotide Reverse Transcriptase Inhibitors (NtRTI)*
Inhibit the action of reverse transcriptase	tenofovir DF (Viread)	Nausea, vomiting, diarrhea
Inhibit the action of reverse transcriptase	Truvada (tenofovir and emtricitabine combination)	Combines side effects of tenofovir and emtricitabine
*Nonnucleoside Reverse Transcriptase Inhibitors (NNRTIs)*		Side effects common to NNRTIs: Rash, erythema multiforme, increased liver enzymes, hepatotoxicity
Combine with reverse transcriptase enzyme to block the process needed to convert HIV RNA into HIV DNA	nevirapine (Viramune)	Gastrointestinal (GI) upset, headache
	delavirdine (Rescriptor)	Headache, fatigue, GI upset, neutropenia, pruritis
	efavirenz (Sustiva)	Dizziness, trouble concentrating, unusual dreams, confusion, anxiety, depression, diarrhea, encephalopathy; false-positive cannabinoid test
	etravirine (Intelence)	Rash, nausea
	rilpivirine (Edurant)	Headache, insomnia, depression, rash
Integrase Inhibitor
Binds with the integrase enzyme and prevents HIV from incorporating its genetic material into the host cell	raltegravir (Isentress)	Diarrhea, nausea, headache, dizziness
Protease Inhibitors (PIs)
Prevent the protease enzyme from cutting HIV proteins into the proper lengths needed to allow viable virions to assemble and bud out from the cell membrane		Adverse effects common to PIs: hyperglycemia, hyperlipidemia, lipodystrophy
	saquinavir (Fortovase, Invirase)	Diarrhea, nausea, headache
	indinavir (Crixivan)	Nausea, diarrhea, asymptomatic hyperbilirubinemia, interstitial nephritis, kidney stones (patient should drink 2-4 L of fluid a day)
	ritonavir (Norvir) most often used in low doses with other PIs to boost effect	Nausea, diarrhea, vomiting, taste perversion, circumoral and perioral paresthesia, hepatitis
	nelfinavir (Viracept)	Diarrhea, flatulence, nausea, rash
	amprenavir (Agenerase)	Nausea, vomiting, headache, taste perversion, perioral paresthesia, severe skin rashes, diarrhea, periorbital paresthesia
	Kaletra (lopinavir and ritonavir combination)	Nausea, diarrhea, taste perversion, perioral and circumoral paresthesia, hepatitis
	atazanavir (Reyataz)	Nausea, diarrhea, hyperbilirubinemia, scleral icterus
	fosamprenavir (Lexiva)	Diarrhea, nausea, vomiting, headache
	tipranavir (Aptivus)	Nausea, diarrhea, headache, clinical hepatitis, increased transaminases, hepatic decompensation, symptoms of sulfa allergy, rash, or photosensitivity
	darunavir (Prezista)	Diarrhea, nausea, headache
Fixed-Dose Combination Products
	Atripla (combination of tenofovir, emtricitabine, and efavirenz)	Combined side effects of tenofovir, emtricitabine, and efavirenz
	Complera (combination of tenofovir, emtricitabine, and rilpivirine)	Combined side effects of tenofovir, emtricitabine, and rilpivirine

^*Many of these drugs cause serious and potentially fatal interactions when used in combination with other commonly used drugs, some of which are available over the counter.

Sources: Centers for Disease Control and Prevention (CDC): Guidelines for the use of antiretroviral agents in HIV-1-infected adults and adolescents, 2012. Available at aidsinfo.nih.gov.

eTABLE 15-4

PATIENT TEACHING GUIDE Proper Use and Placement of Male Condom

You should include the following instructions when teaching a patient about the use of a male condom:

1. Use only condoms that are made with latex or polyurethane. “Natural skin” condoms have pores that HIV can penetrate.

2. Store condoms in a cool, dry place and protect them from trauma. The friction caused by carrying them in a back pocket, for instance, can damage the latex.

3. Do not use a condom past the expiration date or if the package looks worn or punctured.

4. Lubricants used in conjunction with condoms must be water soluble. Oil-based lubricants can weaken latex and increase the risk of tearing or breaking.

5. Nonlubricated, flavored, or unflavored condoms can provide protection during oral intercourse.

6. The condom must be placed on the erect penis before any contact is made with the partner’s mouth, vagina, or rectum to prevent exposure to preejaculatory secretions that may contain HIV.

7. See the figure below for proper steps in male condom placement.

**Proper placement of the male condom. A,** The condom is placed over the glans of the erect penis, being careful to squeeze air out of the reservoir (tip). B and C, The condom is then rolled down the shaft of the penis to the hairline.

8. Remove the penis and condom from the partner’s body immediately after ejaculation and before the erection is lost to keep semen from leaking around the condom as the penis becomes flaccid. Hold the condom at the base of the penis and remove both from the partner’s body at the same time.

9. Wrap used condoms in tissue and discard. Do not dispose in the toilet, because this can cause plumbing problems.

10. Condoms are not reusable! A new condom must be used for every act of intercourse.

eTABLE 15-5

PATIENT TEACHING GUIDE Proper Use and Placement of Female Condom

You should include the following instructions when teaching a patient about the use of a female condom:

1. Female condoms consist of a polyurethane sheath with two spring-form rings.

• The smaller ring is inserted into the vagina and holds the condom in place by anchoring it around the cervix. This ring can be removed if the condom is to be used for anal intercourse. It should not be removed if the condom is to be used for vaginal intercourse.

• The larger ring surrounds the opening to the condom. It functions to keep the condom in place while protecting the external genitalia.

2. Use only water-soluble lubricants with female condoms.

• Female condoms come prelubricated and with a tube of additional lubricant.

• Lubrication is needed to protect the condom from tearing during intercourse and can also decrease noise from friction of the penis against the condom.

3. Some men have reported that the female condom feels better than the male condom. Other men like male condoms better. The only way to find out which type of condom works best is to try them both.

4. Practice inserting the female condom. The steps for proper insertion are shown in the figure below. Lubrication makes the condom slippery, but do not get discouraged—just keep trying.

**Proper placement of the female condom**. A, Inner ring is squeezed for insertion. B, Sheath is inserted similarly to a diaphragm. C, Inner ring is pushed up as far as it can go with the index finger. D, Proper placement of female condom.

5. During sexual intercourse, ensure that the penis is inserted into the female condom through the outer ring. It is possible for the penis to miss the opening, thus making contact with the vaginal or rectal mucosa, and defeating the purpose of the condom.

6. Do not use a male condom at the same time as a female condom.

7. After intercourse, remove the condom before standing up. Twist the outer ring to keep the semen inside, gently pull the condom out of the vagina or rectum, and discard.

8. Do not dispose in the toilet, since this can cause plumbing problems.

9. Do not reuse a female condom.

eTABLE 15-6

PATIENT TEACHING GUIDE Proper Use of Drug-Using Equipment

You should include the following instructions when teaching a patient to safely use drug-using equipment:

1. When injecting drugs, it is always preferable to use new, sterile syringes, needles, cookers, and cotton (works). When snorting or smoking drugs, it is important to use clean pipes and straws.

2. Find out if there is a needle and syringe exchange program in your community. If there is, take used equipment in and you will be provided with new works.

3. In many states, sterile equipment can be purchased without a prescription.

4. Reusing your own equipment is acceptable. Just ensure that no one else uses your equipment and be sure it is clean to decrease the risk of abscesses.

5. If you must share injecting equipment, it is very important to clean the works thoroughly before use.

• First, rinse the used needle and syringe twice with tap water.

• Next, fill the syringe with full-strength household bleach, shake for 30 seconds, and squirt out the bleach.

• Repeat the bleaching process a second time, being sure to shake the bleach-filled syringe for 30 seconds.

• Finally, rinse equipment twice with tap water.

• Do not share your bleach or rinse water.

• Do not share your cooker. If you must share your cooker, clean it with bleach and water before using it again.

6. If you must share pipes or straws, it is very important to clean them thoroughly before use. Soak in bleach and rinse with water.

eTABLE 15-7

NURSING INTERVENTIONS IN HIV INFECTION

Nursing Care and Goals	Assessment	Interventions
Health Promotion
1. Prevent HIV infection.	Risk factors: What behaviors or social, physical, emotional, pathogenic, or immune factors place the patient at risk?	• Education, including knowledge, attitudes, and behaviors, with emphasis on risk reduction to the following: • General population: Cover general information • Pregnant women: General information and information specific to HIV infection and pregnancy • Individual patient: Specific to assessed need • Empower patients to take control of prevention measures.
2. Detect HIV infection early.	Does the patient need to be tested for HIV?	• Provide HIV antibody testing with appropriate counseling.
Acute Intervention
1. Promote health and limit disability.	Physical health: Is the patient experiencing problems?Mental health: How is the patient coping?Resources: Does the patient have family or social support? Is the patient accessing community services? Is money or insurance a problem? Does the patient have access to spiritual support as desired?	• Provide case management. • Teach regarding HIV, the spectrum of infection, options for care, signs and symptoms to report, treatment options, immune enhancement, risk reduction, and ways to adhere to treatment regimens. • Refer to needed resources. • Establish long-term, trusting relationship with patient, family, and significant others. • Provide emotional and spiritual support. • Develop resources for legal needs: discrimination prevention, wills and powers of attorney, child care wishes. • Empower the patient to identify needs, direct care, and seek services.
2. Manage problems caused by HIV infection.	Physical health: Has the patient experienced acute exacerbation of problems related to immunodeficiency, opportunistic disease, or risk factors (e.g., substance use)?Mental health status: Has the patient’s ability to cope with psychosocial issues deteriorated?	• Provide care during acute exacerbations: recognition of life-threatening developments, life support, rapid intervention with treatments and drugs, comfort, and hygiene needs. • Support patient and family during crisis. • Assist the patient with mental health issues and provide referral to mental health specialist as needed.
Ambulatory and Home Care
1. Maximize quality of life.	Physical health: Are new symptoms developing? Is the patient experiencing drug side effects or interactions?	• Continue case management. • Teach about changing treatment options and continued adherence. • Empower patient to continue to direct care and to make desires known to family members and significant others.
2. Resolve life and death issues.	Mental health: How is the patient coping? What adjustments have been made?Finances: Can the patient maintain health care and basic standards of living?Family, social, and community supports: Are these available? Is the patient using supports in an effective manner? Do family or significant others need teaching, encouragement, or stress relief?Spirituality issues: Does the patient desire support from a religious organization or spiritual counselor? What assistance does the patient desire?	• Continue physical care for chronic disease process: treatments, drugs, comfort, and hygiene needs. • Encourage health promotion measures (as above). • Refer the patient to resources to support finances. • Support patient and family or significant others in a trusting relationship. • Assist with end-of-life issues: resuscitation orders, comfort measures, funeral plans, estate planning, child care continuation, etc. • Assess desires and refer to resources that will assist in meeting identified spiritual needs.

Types of Pathogens

The many different kinds of pathogens can be classified into several groups, including bacteria, viruses, fungi, protozoa, and prions.³ Bacteria are one-celled organisms that are common throughout nature. Many bacteria are normal flora. They live harmoniously in or on the human body without causing disease under normal circumstances. Normal flora protect the human body by preventing the overgrowth of other microorganisms. For example, Escherichia coli is a bacteria that is part of the normal flora in the large intestine.

Bacteria cause disease in two ways: by entering the body and growing inside human cells (e.g., TB) or by secreting toxins that damage cells (e.g., Staphylococcus aureus). Bacteria are divided into categories based on the shape of their cells. Cocci, such as streptococci and staphylococci, are round. Bacilli are rod shaped and include tetanus and TB. Curved rods include Vibrio bacteria, one of which causes cholera. Spirochetes are spiral shaped and include the organisms that cause leprosy and syphilis. Table 15-1 lists common pathogenic bacteria and the diseases that they cause.

TABLE 15-1

DISEASE-CAUSING BACTERIA

Bacteria	Diseases Caused
Clostridia
• Clostridium botulinum	Food poisoning with progressive muscle paralysis
• Clostridium tetani	Tetanus (lockjaw)
Corynebacterium diphtheriae	Diphtheria
Escherichia coli	Urinary tract infections, peritonitis, hemolytic-uremic syndrome
Haemophilus
• Haemophilus influenzae	Nasopharyngitis, meningitis, pneumonia
• Haemophilus pertussis	Pertussis (whooping cough)
Helicobacter pylori	Peptic ulcers, gastritis
Klebsiella-Enterobacter organisms	Urinary tract infections, peritonitis, pneumonia
Legionella pneumophila	Pneumonia (Legionnaires’ disease)
Mycobacteria
• Mycobacterium leprae	Hansen’s disease (leprosy)
• Mycobacterium tuberculosis	Tuberculosis
Neisseriae
• Neisseria gonorrhoeae	Gonorrhea, pelvic inflammatory disease
• Neisseria meningitidis	Meningococcemia, meningitis
Proteus species	Urinary tract infections, peritonitis
Pseudomonas aeruginosa	Urinary tract infections, meningitis
Salmonella
• Salmonella typhi	Typhoid fever
• Other Salmonella organisms	Food poisoning, gastroenteritis
Shigella	Shigellosis; diarrhea, abdominal pain, and fever (dysentery)
Staphylococcus aureus	Skin infections, pneumonia, urinary tract infections, acute osteomyelitis, toxic shock syndrome
Streptococci
• Streptococcus faecalis	Genitourinary infection, infection of surgical wounds
• Streptococcus pneumoniae	Pneumococcal pneumonia
• Streptococcus pyogenes (group A β-hemolytic streptococci)	Pharyngitis, scarlet fever, rheumatic fever, acute glomerulonephritis, erysipelas, pneumonia
• S. pyogenes (group B β-hemolytic streptococci)	Urinary tract infections
• Streptococcus viridans	Bacterial endocarditis
Treponema pallidum	Syphilis

Viruses, unlike bacteria, do not have a cellular structure. They are simple infectious particles that consist of a small amount of genetic material (either ribonucleic acid [RNA] or deoxyribonucleic acid [DNA]) and a protein envelope. Viruses can reproduce only after releasing their genetic material into the cell of another living organism. Examples of diseases caused by viruses are shown in Table 15-2.

TABLE 15-2

DISEASE-CAUSING VIRUSES

Virus	Diseases Caused
Adenoviruses	Upper respiratory tract infection, pneumonia
Arbovirus	Syndrome of fever, malaise, headache, myalgia; aseptic meningitis; encephalitis
Coronavirus	Upper respiratory tract infection
Coxsackieviruses A and B	Upper respiratory tract infection, gastroenteritis, acute myocarditis, aseptic meningitis
Echoviruses	Upper respiratory tract infection, gastroenteritis, aseptic meningitis
Hepatitis A, B, C	Viral hepatitis
Herpesviruses
• Cytomegalovirus (CMV)	Gastroenteritis; pneumonia and retinal damage in immunosuppressed individuals, infectious mononucleosis–like syndrome
• Epstein-Barr	Mononucleosis, Burkitt’s lymphoma (possibly)
• Herpes simplex type 1	Herpes labialis (“fever blisters”), genital herpes infection
• Herpes simplex type 2	Genital herpes infection
• Varicella-zoster	Chickenpox, shingles
Human immunodeficiency virus (HIV)	HIV infection, AIDS
Influenza A and B	Upper respiratory tract infection, H1N1 (swine) flu, avian (bird) flu
Mumps	Parotitis, orchitis in postpubertal males
Papillomavirus	Warts
Parainfluenza 1-4	Upper respiratory tract infection
Parvovirus	Gastroenteritis
Poliovirus	Poliomyelitis
Pox viruses	Smallpox
Reoviruses 1, 2, 3	Upper respiratory tract infection
Respiratory syncytial virus	Gastroenteritis, respiratory tract infection
Rhabdovirus	Rabies
Rhinovirus	Upper respiratory tract infection, pneumonia
Rotaviruses	Gastroenteritis
Rubella	German measles
Rubeola	Measles
West Nile virus	Flulike symptoms, meningitis, encephalitis

Fungi are organisms similar to plants, but they lack chlorophyll. Mycosis is any disease caused by a fungus. Pathogenic fungi cause infections that are usually localized but can become disseminated in an immunocompromised person. Tinea pedis (athlete’s foot) and tinea corporis (ringworm) are two common mycotic infections. Some fungi are normal flora in the body, but when overgrowth occurs, disease can result. Overgrowth of Candida albicans, for example, can cause candidiasis in the mouth (thrush), esophagus, intestines, and vagina. Other fungi and their respective mycotic infections are listed in Table 15-3.

TABLE 15-3

DISEASE-CAUSING FUNGI

Fungi	Diseases Caused	Organs Affected
Aspergillus fumigatus	Aspergillosis	Lungs*
Aspergillus fumigatus	Otomycosis	Ears
Blastomyces dermatitidis	Blastomycosis	Lungs, various organs
Candida albicans	Candidiasis	Intestines
	Vaginitis	Vagina
	Thrush	Skin,† mouth
Coccidioides immitis	Coccidioidomycosis	Lungs*
Pneumocystis jiroveci	Pneumocystis pneumonia (PCP)	Lungs*
Sporothrix schenckii	Sporotrichosis	Skin, lymph vessels
Trichophyton	Tinea pedis	Skin†
Microsporum	Tinea capitis	Skin†
Epidermophyton	Tinea corporis	Skin†

^*See Table 28-14: Fungal Infections of the Lung.

^†See Table 24-6: Common Fungal Infections of the Skin.

Protozoa are single-cell, animal-like microorganisms. Protozoa normally live in soil and bodies of water. When introduced into the human body, they can cause infection. Amebic dysentery and giardiasis are caused by protozoal parasites. Malaria is caused by a sporozoa called Plasmodium malariae.

Prions are infectious particles that contain abnormally shaped proteins. Not all prions cause disease, but those that do typically affect the nervous system. They can cause a group of illnesses called transmissible spongiform encephalopathies (TSEs). Some of the more common TSEs are Creutzfeldt-Jakob disease and bovine spongiform encephalopathy in cattle (also known as mad cow disease).⁴

Emerging Infections

An emerging infection is an infectious disease that has recently increased in incidence or that threatens to increase in the immediate future. Examples of emerging infections are described in Table 15-4. Emerging infectious diseases can originate from unknown sources or from contact with animals, changes in known diseases, or biologic warfare. For example, severe acute respiratory syndrome (SARS) and the West Nile virus come from animal sources. Others emerged when a previously treatable organism (e.g., S. aureus) developed resistance to antibiotics.

TABLE 15-4

EMERGING INFECTIONS

Microorganism	Related Disease
Bacteria
Borrelia burgdorferi	Lyme disease
Campylobacter jejuni	Diarrhea
Escherichia coli O157:H7	Hemorrhagic colitis, hemolytic-uremic syndrome
Helicobacter pylori	Peptic ulcer disease
Legionella pneumophila	Pneumonia (Legionnaires’ disease)
Vibrio cholerae 0139	New strain associated with epidemic cholera
Virus
Ebola virus	Ebola hemorrhagic fever
H1N1	H1N1 (swine) flu
Hantavirus	Hemorrhagic fever associated with severe pulmonary syndrome
Hepatitis C virus	Parenterally transmitted hepatitis
Hepatitis E virus	Enterically transmitted hepatitis
Human immunodeficiency virus (HIV)	HIV infection and AIDS
Human herpesvirus 6 (HHV-6)	Roseola subitum
Human herpesvirus 8 (HHV-8)	Associated with Kaposi sarcoma in immunosuppressed patients, including people with HIV infection
West Nile virus	West Nile fever
Parasite
Cryptosporidium parvum	Acute and chronic diarrhea

The battle against infection is not new, but modern technologies have changed the rules of the game. Global travel, population density, encroachment into new environments, misuse of antibiotics, and bioterrorism have increased the risk for widespread distribution of emerging infections.⁵

Not too long ago many believed that science had conquered infectious disease. However, newly recognized infectious diseases have emerged in recent decades. These include HIV, Lyme disease, hepatitis C, SARS, Ebola virus, and influenza A (H1N1) virus. Some diseases once thought to be under control, such as TB, measles, and pertussis, have reemerged.⁶

Studies in zoonosis (the science of transmission of diseases from animals to humans) have shown that many known infectious diseases come from animal and insect vectors. The SARS outbreak in China in 2003, for instance, was linked to the civet cat, a small carnivorous mammal found throughout much of Asia and Africa. (SARS is discussed in Chapter 68.)

West Nile virus is carried and transmitted by mosquitoes. Mosquitoes acquire the virus as they draw blood from infected animals and people. The virus does not cause illness in the mosquito, but can be transferred to uninfected animals and humans as the mosquito continues to feed. Bird deaths are an early warning sign of a West Nile virus outbreak, which can spread quickly if action is not taken in a timely manner. (West Nile virus is discussed in Chapter 57.)

Influenza viruses are examples of how disease can spread between animals and humans. Variants of influenza A viruses were responsible for influenza epidemics. These include the 2009 influenza A (H1N1) outbreak that was traced back to pigs, hence the name swine flu. In 1997 and 2003 outbreaks of the influenza A (H5N1) strain of avian flu resulted from transmission of influenza virus from chickens to humans.⁷

Ebola virus has presented an ongoing challenge to public health since it was first seen in 1976. Ebola virus causes severe hemorrhagic fever and is usually lethal. Therapeutic and preventive measures are extremely limited. The natural reservoir and path of transmission are unknown, which makes it impossible to effectively combat Ebola virus and the disease it causes.⁸

Reemerging Infections

Vaccines and proper medications have led to the near eradication of some infections (e.g., smallpox and polio), but infective agents can reemerge if conditions are right. Table 15-5 presents some diseases that have shown resurgence in recent decades.

TABLE 15-5

REEMERGING INFECTIONS

Microorganism	Infection	Description
Bacteria
Corynebacterium diphtheriae	Diphtheria	Localized infection of mucous membranes or skin.
Bordetella pertussis	Pertussis	Acute, highly contagious respiratory disease characterized by loud whooping inspiration. Also known as whooping cough.
Yersinia pestis	Plague	Bubonic: swollen glands, fever, chills, headache, and extreme exhaustion.Pneumonic: overwhelming pneumonia with high fever, cough, bloody sputum, and chills.
Mycobacterium tuberculosis	Tuberculosis	Chronic infection transmitted by inhalation of infected droplets (see Chapter 28).
Virus
Dengue viruses (flaviviruses)	Dengue fever	Acute infection transmitted by mosquitoes and occurring mainly in tropical and subtropical regions.
Parasite
Giardia	Giardiasis	Diarrheal illness that usually originates in water contaminated with fecal matter. Also known as traveler’s diarrhea.