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Infection control; Transmissible Disease
- 1. Infection Control:Infection Control: Transmissible DiseasesTransmissible Diseases
- 2. Infection Control: • Objectives: Protect patients, dental professional, and others from exposure to acquired infection in dental environment.
- 3. Standard Precautions • Definition: Blood, all body fluids, secretions, and excretions (except sweat) are treated as if known infection.
- 4. Microorganisms of the Oral Cavity • Infection potential- bacteria come from dorsum of tongue, dental biofilm, periodontal pockets, caries. • Cross-contamination occurs: – Person to person – Person to inanimate object – Inanimate object to another person
- 5. Review Cross-contamination refers to the spread of microorganisms from one source to another; this may include which of the following? A) Person to person, person to inanimate object, and inanimate object to person B) Person to inanimate object only C) Inanimate object to person only D) Person to person only E) Person to inanimate object and inanimate object to person only
- 6. Answer A) Person to person, person to inanimate object, and inanimate object to person Person to person, person to inanimate object, and inanimate object to person are all possible sources of cross-contamination.
- 8. Factors Influencing the Development of Infection • Number of organisms, duration of exposure • Virulence of the organism: strength of pathology • Immune status of host: ability to resist infection • Host general physical health and nutritional status
- 9. Factors That Alter Normal Defenses • Abnormal physical conditions: defective heart valve as congenital or acquired condition • Systemic diseases: diabetes mellitus, alcoholism, leukemia, AIDS • Drug therapy: Steroids and chemotherapeutic agents • Prostheses and transplants: joint replacement, cardiac prosthesis, shunts, organ transplant
- 10. Air-borne Infection • Dust-borne organisms • Aerosol production – Aerosols: less than 50um in diameter, invisible, suspended in air for long periods, may contain respiratory disease organisms – Spatter: Spatter-heavier, larger particles greater than 50um, air-borne shorter time, may be visible – Origin: Produced during all intraoral procedures, including examination and treatment – Contents: single or clumps of mo adhere to dust or debrie particles from mouth
- 11. Prevention of Transmission • Pre-procedural oral hygiene measures: biofilm removal; brushing, flossing, mouthrinse • Interruption of transmission: rubber dam, high evacuation, manual instrumentation, ventilation, filtration • Clean water: EPA standards. Run water lines 2 minutes before and after patient in clinic • Protection of the clinician: PPE’s
- 12. Pathogens Transmissible by the Oral Cavity • Tuberculosis • Viral hepatitis • AIDS • Herpetic infections • Table 2-1 p 28
- 13. Active TB Infection Active: incubation as long as 10 weeks • Usually has a skin or blood test result indicating TB infection • May have an abnormal chest x-ray or positive sputum smear • Has active TB bacteria in body • Usually feels sick with coughing, fever, and weight loss • May spread TB to others • Needs treatment to treat active disease
- 14. Latent TB Infection Latent: • Usually has a skin or blood test result indicating TB infection • Has a normal chest x-ray or negative sputum smear • Has inactive TB bacteria body • Does not feel sick, cannot spread to others • May need treatment for latent TB infection to prevent active TB disease
- 15. How is Active TB Spread? • Most communicability just before diagnoses • Spread by inhalation, inoculation and mucous
- 16. Who is at risk for Active TB? • Born in country with high TB burden (Asia, India, Latin America, Soviet Union) • Child of parents born in country with endemic TB • Close contact to person with active TB • Living and working in congested settings (shelters, long term care) • Medically underserved (low income, uninsured, drug abuse)
- 17. HIV and TB • HIV testing is recommended for all TB suspects or confirmed cases • HIV + persons with TB disease have higher HIV viral loads that HIV + persons without TB disease • HIV disease can mask TB symptoms and vice versa • HIV + person who are skin test+ have an increased annual risk of TB disease
- 18. Active TB Treatment Standard Drug Regimen; RIPE taken for several months • Rifampin • Isoniazid • Pyrazinamide • Ethambutol Is a drug resistant illness
- 19. Droplet Nuclei
- 20. Viral Hepatitis • Inflammation of the liver • Strains of hepatitis –Hepatitis A, B, C, D, E –Non-ABCDE –G (HGV)
- 21. Hepatitis A(HAV) • Jaundice, influenza type symptoms, not a chronic infection • Water and food borne, poor food handling, unwashed hand, fecal/oral route. Best defense is handwashing • No carrier state . May treat in clinic. May use the ultrasonic scaler. • Traveling to at risk areas, homosexual men, iv drug uses, hemophiliacs, liver disease • Immunization available
- 22. Hepatitis B (HBV) • Very serious, prolonged illness, liver cancer, significantly increased occupational hazard of healthcare workers • 5-10% carrier state. Virus remains in blood and can be found in blood products during prophylaxis, body fluids and saliva. Do not treat patients with active Hepatitis B. • Needlesticks , sexual and perinatal exposure, blood transfusion occupation, lifestyle, drug abuse • Immunization available
- 23. Hepatitis C (HCV) • Flu-like symptoms. 50-80% chronic carries, 70% liver disease . Most reason for liver transplants. • Do not use ultrasonic scaler with previous history. • Male, alcoholism, HIV or HBV, blood transfusion before 1991, IV drug abuse, tattooing, piercing, organ transplantation • No Immunization. Behavior modification, infection control
- 24. Hepatitis D(HDV) • Signs and symptoms resemble HBV. Patients with Hepatitis D also have Hepatitis B • Do not use ultrasonic scaler with previous history • Immunization with HBV vaccine also protects the recipient from delta hepatitis infection.
- 25. Hepatitis E • HEV formerly known as enterically transmitted non-A, non-B hepatitis. Water-borne epidemics. • No carrier state. May use ultrasonic scaler. Patient fully recovers and does not carry the virus in the bloodstream. • Transmitted by contaminated water, person to person, and fecal oral route. • No Immunization: sanitary disposal of wastes; handwashing, especially before handling food.
- 26. Tips for Remembering Types of Hepatitis • Consonants refer to the blood-born strains B, C, D • Vowels refer to fecal-oral transmission A, E
- 27. Herpes Virus Diseases • Highly contagious, eight are known to infect humans. • Relation to periodontal infections: opportunistic periodontal pathogens can occur, making periodontal disease symptoms more severe.
- 29. Types of Herpes Infection • Herpetic whitlow: infection of fingers contacted via skin abrasions from lesion • Ocular herpes: HSV 1 or HSV 2 infection of eye • Herpes simplex type 1 (HSV-1): Oral herpes. HSV 1 and HSV 2 cannot be distinguished clinically • Herpes simplex type 2 (HSV-2): Genital herpes. Antiviral therapy can suppress lesion, but latency can never be erased. Most common STD • Postpone appointment for active lesions. Acyclovir, an antiviral drug of choice for treatment for HSV2
- 30. Types of Herpes Infection Varicella-herpes zoster virus (HZV): • Chickenpox: Varicella; highly contagious, acute infection • Shingles: Herpes zoster; lantent in dorsal root ganglia. Unilateral eruptions, may occur intraoral Epstein-Barr virus EBV: • Infectious mononucleosis: flu-like symptoms, transmitted by saliva or droplets, last carrier state • Hairy leukoplakia: associated with AIDS, white, lesion on lateral borders of tongue
- 31. Types of Herpes Infections • Cytomegalovirus (HCMV HHV-5): Adult infection; immunodeficient or immunosuppressed patients • Herpes lymphotrophic virus (HHV-6): Childhood infection (6 months to 2 years), roseola infantum, with accompanying high temperature and rash • Human herpes virus-7 (HHV-7): prevalent in general population, detected in both healthy gingiva and diseased periodontal tissues. • Kaposi sarcoma-related virus (KSRV)(HHV-8): immunocompromised host, a major cofactor in production of Kaposi sarcoma, an AIDS-defining lesion.
- 33. Human Papilloma Virus (HPV) • Over 100 types of HPV • 40 types infect the genitals, throat, and mouth • Types 16 and 18 are the cause of 70% of cervical cancers • 90 % of genital warts cases are caused by 6 and 11 • HPV testing is available for women undergoing cervical cancer screening
- 34. HIV Infection • Slow, progressive, lethal pandemic caused by infection with the human immunodeficiency virus. • Found in most body fluids; transmitted via blood, semen, vaginal secretions, and breast milk. • Obtain permission to treat from physician. Do not use the ultrasonic scaler. Legally need to treat patient • Unprotected sexual contact with infected person, IV drug users (sharing needles), transplantation of organs and tissues, occupational exposure, perinatal transmission, hemophiliacs
- 35. Methicillin-Resistant Staphylococcus Aureus • MRSA is a common infection that is resistant to many antibiotic therapies. • Endemic in hospitals and institutions. • It is associated with acute osteomyelitis, bacteremia, septicemia, cellulitis, conjunctivitis, pneumonia, and toxic shock syndrome. • Infection is spread by direct and indirect contact by skin scales, fomites, equipment, and the environment. • Incubation period is 4-10 days
- 36. When HIV becomes AIDS • http://www.youtube.com/watch?v=68I7JlVhuhY
Editor's Notes
- In utero, the oral cavity is sterile. After birth, within a few hours, a simple oral flora develops. Microorganisms are transmitted to the infant from mother and other family members or caretakers. As infant grows, there is continuing introduction of microorganisms. Normal adult microbiota is very complex. Many salivary bacteria come from dorsum of tongue. Some bacteria are from mucous membranes and gingival/periodontal tissues.
- Infectious agent: the invading organism; each organism has its own specific reaction in an infected host. Reservoir: where invading organisms live and multiply. Port of exit: mode of escape from the reservoir; organisms exit through body systems such as the respiratory tract, or though skin lesions. Escape from bloodstream may be through skin abrasions, hypodermic needles, or dental instruments. Mode of transmission: direct, person to person; or indirect by way of intermediate vehicle such as contaminated hands or instrument. Transmission by droplet may be direct from respiratory tract of one person to oral cavity of receiving host. Droplets may also pass indirectly to hands or inanimate objects to be transferred indirectly to susceptible host. Port of entry of infectious agent into new host. Modes of entry may be similar to modes of exit. Susceptible host: does not have immunity to the invading infectious agent.
- Patient’s complete medical/dental history is reviewed, specific problems are identified, and necessary precautions or modifications to care noted. Abnormal conditions: defective heart valve as congenital or acquired condition. Valve defect leaves individual susceptible to infectious endocarditis resulting from dental/dental hygiene invasive procedures. Systemic diseases: diabetes mellitus, alcoholism, leukemia, , AIDS, and other instances of immunosuppression increase susceptibility to infection. Drug therapy: agents used in treatment of systemic diseases alter body’s defenses. Steroids and chemotherapeutic agents are immunosuppressive. Prophylactic antibiotics may be indicated to prevent infection. Prostheses and transplants: joint replacement, cardiac prosthesis, shunts for hydrocephalus, or an organ transplant may require antibiotic premedication for invasive dental procedures.
- Dust-bacteria may travel in dust from outside into and within the dental environment Aerosols-classified by particle size, less than 50um in diameter, invisible, suspended in air for long periods, may contain respiratory disease organisms Spatter-heaviers, larger particles greater than 50um, air-borne shorter time, may be visible Origin-created during breathing, speaking, coughing, sneezing. Dental; scaling, air/water spray, polishing, ultrasonic Content; single or clumps of mo adhere to dust or debrie particles from mouth
- Preprocedural: biofilm removal (toothbrushing, flossing) and using antiseptic mouthrinse to reduce numbers of bacteria in aerosols. Interruption: use of rubber dam, high-volume evacuation, and manual instrumentation as much as possible. Install air control methods to supply adequate ventilation, filtration, and relative humidity. Employ vacuum-cleaning methods (with filter to trap organisms after their suctioned) rather than dust-arousing housekeeping methods. Clean water: use water that meets EPA regulatory standards for drinking water (less than 500 CFU/mL of heterotrophic water bacteria). Run water through dental equipment lines (handpieces, ultrasonic scalers, air/water syringes) at least 2 minutes at the start of the day and at least 20 to 30 seconds after each patient during the day. Clinician’s protection: use of mask, shields, and protective eyewear can prevent direct contact of spatter and aerosols with faces of DHCP. Patient protection: use of protective eyewear can prevent direct spatter and aerosols to the face and eyes of the patient.
- TB HEP A, B, C,D HIV Herpes type 1, 2, Zoster
- Tuberculosis: special consideration when sterilization and disinfection methods are selected and administered. Incidence of TB has increased in population groups with high prevalence of HIV, and is an AIDS-defining illness. Transmission is by inhalation of fresh droplets containing tubercle bacilli disseminated from sputum and saliva of infected individual by coughing, sneezing, or breathing heavily. Aerosols created in the dental environment during procedures can carry the bacilli as well. Degree to which infected individual produces infectious droplets depends on amount and duration of exposure and susceptibility of the recipient. Maximum communicability is just before the disease is diagnosed. Incubation period may be as long as 10 weeks. Early symptoms include low-grade fever, loss of appetite, weight loss, and tiring easily. There may be a slight cough and eventually sputum, indicating presence of tubercle bacilli in throat and saliva. Later symptoms show definite temperature elevation, night sweats, weakness, and a persistent cough. Diagnosis is by chest radiograph and tuberculin testing. Reactive TB focus of an infection may remain inactive and later produce a recurrence. Primary treatment may have been incomplete. Reactivity may be related to a debilitating condition or immunosuppression. Multidrug-resistant TB: if meds not prescribed or taken properly, the tubercle bacilli can become resistant. Usual course of drug therapy is daily/weekly meds taken for at least 6 months to treat active TB. Principal drugs (or in combination) are isoniazid, pyrazinamide, rifampin, and ethambutol. First line of prevention for multidrug-resistant TB is early diagnosis followed by directly observed therapy (DOT). Second approach is to locate and treat persons with latent TB, particularly those at high risk of reactivation. Extensively drug-resistant (XDR) TB: multidrug-resistant strains are resistant to at least isoniazid and rifampin, and requires use of second-line drugs for treatment. Reports reveal case of XDR TB emerging that were resistant to all second-line drugs. Cases of XDR are noted to be especially severe in immunosuppressed patients infected with HIV. Clinical management: official CDC recommendations: periodic risk assessment, taking and updating medical history reviews, including questioning of history of TB and symptoms suggestive of the disease; referral of patients with suggestive TB history or symptoms for medical evaluation; deferral of elective dental treatment (Table 2-2 in text provides guide to patient management); urgent dental care be provided in a facility that can offer isolation, optimal ventilation, and use of highest filtration-level mask for respiratory protection. DHCPs should present for prompt medical evaluation if they have a persistent cough, combined with weight loss, fever, and other symptoms. A separate reception area for suspected or confirmed TB patients is preferred, and appointment scheduling should be arranged to prevent a waiting period. Clinical findings include lymphadenopathy, and oral lesions, although relatively rare, can be in the form of ulcers on the soft/hard palate or tongue. Within a few weeks of beginning the drug therapies, bacilli in the sputum, cough, and infectivity are decreased.
- Droplet nuclei. Many potentially pathogenic microorganisms are disseminated by aerosols and spatter. The primary mode of transmission of tubercle bacilli is by droplet nuclei breathed directly into the lung. But can also be transmitted by inoculation and contact with mucous membranes
- New viruses designated non-acde and hep g have emerged in post transfusion patients or injection drug users
- General Facts: most common strain worldwide. Occurs more frequently in children and young adults Transmission: fecal/oral, unsanitary conditions, unwashed hands. Hygiene critical Process: water and food borne, poor food handling, blood-borne:early days of infection Incubation; 15-45 days, 2-3 weeks before jaundice infection is communicable, after, it dimishes. No carrier.
- HBV incidence increased significantly during past 20 years; is a serious occupational hazard for healthcare personnel (HCP). Use of strict sterilization of equipment and materials, aseptic techniques, and self-protection for HCP is MANDATORY. HBV occurs at any age and differs from HAV in mode of transmission, length of incubation period, onset, and existence of chronic carrier state. Transmission: by percutaneous and permucosal exposure; needlestick or sharps injury; intravenous, intramuscular, subcutaneous injury; perinatal exposure; exchange of contaminated needles, syringes, or other intravenous drug user paraphernalia; sexual exposure; infection from blood transfusion and blood products. Perinatal transmission: during fetal stage, at birth. Infected infant at high risk for chronic infection, which can lead to chronic liver disease or cancer later in life. Preventive measures for pregnant women to be tested for HBsAg and HBeAg. Individuals at risk or with risk behaviors: factors including occupation, place of residence, lifestyle, confinement to an institution, other diseases and their treatments, and parenteral drug abuse. HCP who adhere to standard precautions with use of protective barriers (gloves, masks, eyewear), who follow essential precautions for blood and other potentially infectious materials, and who have immunity following vaccination or acquired antibody to HBV are at low risk. Disease process: incubation ranges from 2 to 6 months, with an average of 60 to 90 days. HBsAg may be detected in blood as early as 30 days after exposure to the virus. Presence of serum HBsAg indicates communicability. Transient subclinical infection: majority of patients do not have icteric stage, but do have subclinical disease; many individuals remain undiagnosed but develop antibodies and permanent immunity. Individual has rapid, strong immune response to HBV and virus is cleared before it can become established. Acute type B hepatitis: cannot be distinguished from other viral hepatitis infections on basis of clinical signs and symptoms. Preicteric stage (onset) with fever, malaise, and influenza-like symptoms typical of all types of hepatitis. Onset may be slower and more insidious, including skin rash, itching, and joint pain. Convalescence begins with disappearance of jaundice. During this period, antibody increases except in those who become permanent carriers. Carrier state: chronic carrier is defined as individual with the HBsAg marker in the blood serum for more than 6 months. Many carriers eventually develop cirrhosis or cancer of the liver. Death from chronic liver disease occurs in 15% to 20% of persons infected. Immunity: presence of HBV antibodies in the serum show previous exposure to HBV, and is therefore immune to reinfection. Pretesting for anit-HBs prior to vaccination for HBV may be indicated. Prevention: critical occupational hazard for DHCP due to close association with potentially infected body fluids of patients. Every HCP needs to be immunized to minimize possibility of disease acquisition and transmission. Postexposure prophylaxis (PEP): indications for newborns of HBsAg-positive mothers; exposure to HBsAg-positive blood. High-titer anti-HBs immune globulin (HBIG) is available for PEP.
- Associated with blood transfusion and the use of contaminated needles. Now recognized as the MOST common chronic blood-borne infection in the U.S., and most frequent indication for liver transplantation. Serologic test for antibody to HCV has been developed, and is an established test for blood donors. Transmission: can be acquired by percutaneous exposure to contaminated blood and plasma derivatives, contaminated needles and syringes, transfusion, or accidental needlestick. HCV has been demonstrated in saliva. Nonpercutaneous routes include sexual transmission and perinatal exposure. Disease process: onset of HCV can have no clinical symptoms, or patient can have abdominal discomfort, nausea, and vomiting and can progress to jaundice. After acute infection, 50% to 80% will become chronically infected (carriers) and more than 70% will develop serious liver disease. The course of chronic liver disease may progress without symptoms for the first 20 years after infection. First diagnosis may be during blood donor screening or detection of elevated liver enzymes during routine physical examination. Risk factors: age greater than 40 years at infection, males, moderate to heavy alcohol intake, and coinfection with HIV or HBV. Principle risk factors for HCV include blood transfusion (before 1991), injection drug use, intranasal cocaine use, tattooing, ear/body piercing, perinatal transmission, sexual transmission, hemodialysis, and organ transplantation. Prevention and control: since no vaccine is available for HCV, behavior modification is essential, including STRICT ATTENTION to infection control procedures for all HCP. Measures recommended for HBV can be applied to HCV.
- Delta hepatitis virus, also called the delta agent, causes infection ONLY in the presence of HBV infection. Diagram shows the delta antigen surrounded by HBsAg. Transmission: most frequently, delta infection is superimposed on HBsAg carriers. Occurs primarily in individuals with multiple exposures to HBV, especially those with hemophilia and intravenous drug use. Transmission similar to that of HBV, by direct exposure to contaminated blood and serous body fluids, contaminated needles and syringes, sexual contacts, and perinatal transfer. Disease process: more severe with a greater mortality rate than with HBV alone. Onset is abrupt; signs and symptoms resemble HBV. Infection can occur in following ways: Coinfection: acute delta hepatitis occurring with acute HBV infection may lead to resolution of both types. Clearance of HBV may lead to clearance of delta virus. Superinfection: acute delta type superimposed on an existing carrier HBV state. HBV carrier state remains unchanged and delta carrier state may develop in addition. Superimposition: chronic delta hepatitis superimposed on chronic HBsAg carrier. Prevention: all measures used to prevent HBV prevent HDV since delta is dependent on presence of HBV. Immunization with HBV vaccine also protects the recipient from delta hepatitis infection.
- HEV formerly known as enterically transmitted non-A, non-B hepatitis. Clinical course and distribution similar to HAV. Associated with water-borne epidemics. Transmission: HEV transmitted by contaminated water, as well as person-to-person by fecal-oral route. Reported large outbreaks associated with fecally contaminated water sources after heavy rains where sewage disposal was inadequate. Adults affected more than children. Mortality rate in pregnant women has been high. Prevention and control: sanitary disposal of wastes; handwashing, especially before handling food. Application in dental setting: strict infection control and daily cleansing of unit water lines.
- Herpes virus infections represent wide variety of disease entities that are highly contagious and antigenically distinct. Of know herpes strains, only eight are known to infect humans. These eight have significance for oral health care. Herpes viruses produce diseases with latent, recurrent, and sometimes malignant tendencies. HS type 2 has been implicated in cervical cancer, and HS type 1 in oral cancer. After infection, the virus has the ability to remain latent in the individual and only become reactivated to produce recurrent infection after certain stimuli or when the body’s immune response is significantly lowered. Immunosuppressed patients have more frequent and severe herpes infections. Herpes viruses are among opportunistic organisms in AIDS. Relation to periodontal infections: human herpes viruses occur in periodontitis, found in pocket flora with relatively high prevalence. Infection with herpes viruses can suppress a patient’s immunity, and as a result, subgingival overgrowth of opportunistic periodontal pathogens can occur, making periodontal disease symptoms more severe. HSV-1: primary infection usually occurs in children, but may occur at any age. Antibodies (anti-HSV) are produced, but do not guarantee immunity to recurrent herpes or other herpes virus infections. Sulcular epithelium can serve as reservoir for the viruses. Anti-HSV is present in gingival sulcus fluid. The possibility exists that trauma to oral tissues during dental or DH appointment may bring about herpetic recurrence. Primary herpetic gingivostomatitis: primary infection with HSV-1 may be mild and isolated to marginal and attached gingiva. Full-blown case presents with widespread oral ulcers that may involve pharyngeal areas. When clinical disease is evident, gingivostomatitis and pharyngitis are most frequent manifestations, with fever, malaise, inability to eat, and 2- to 7-day course of lymphadenopathy. Painful oral vesicular lesions may occur on gingiva, mucosa, tongue, and lips. Patient may be subclinical carrier, and reactivation from trigeminal ganglia may be followed by asymptomatic excretion of viruses in the saliva. Reactivation may also lead to herpetic ulcerations of the lip, the typical “cold sore.” Herpes labialis (cold sore, fever blister): both HSV-1 and HSV-2 cause genital and oral-facial infections that cannot be distinguished clinically. Reactivation of oral-facial HSV-1 infections are more frequent than oral-facial HSV-2. Recurrent HSV lesions are usually triggered by stress, sunlight, illness, or trauma. Emotional stress and oral trauma of a patient’s dental appointment may well trigger the reactivation. Prodrome: before the local lesion appears, a forewarning (prodrome) manifested as burning or slight stinging sensations with slight swelling may appear. The recurrent lesion most frequently appears at the vermilion border of the lower lip, but can occur intraorally on the gingiva or hard palate. Clinical characteristics: a group of vesicles form and eventually ruptures and coalesces. Crusting follows and healing may take up to 10 days. The lesions are infectious, with viral shedding. Care must be taken by the patient because autoinfection (to eye, nose, or genitals) is possible, as is infection of other people
- Latent infection of herpes simplex virus. Path of the virus traced from point of viral penetration on lip to establishment of latent infection in the trigeminal ganglion. Triggered by UV light, stress and trama
- Whitlow: HSV-1 infection of the fingers that results from viral entry through minor skin abrasions, most frequently found around a fingernail. Transmission occurs from direct contact with vesicular lesion on patient’s lip or with saliva containing viruses. Autoinfection from lip or intraoral herpetic lesion possible while nail biting. Prevention is with use of protective gloves during dental procedures. With standard precautions for infection control, whitlow has become nearly extinct. Ocular herpes: can be primary or recurrent infection in the eye from HSV-1 or HSV-2. Transmission from splashing saliva or fluid from a vesicular lesion directly into an UNPROTECTED eye. It can also be extension of a facial lesion or infection of infant’s eye in utero or during birth. Symptoms include fever, pain, blurring of vision, swelling, excess tears, and secondary bacterial infection. Herpetic keratoconjunctivitis can cause deep inflammation and when left untreated is a leading cause of loss of sight. Prevention: with standard precautions and use of proper personal protection including eye covering for both clinician and patient, ocular herpetic infection can be prevented. HSV-2: commonly known as genital herpes, but also occurs as an oral and perioral infection. Antiviral therapy can suppress HSV-2 lesions, but the latency of the virus can never be eradicated. Clinical management: patient history should question the experience with herpes viruses. Use patient-friendly terms such as “cold sore” or “fever blister.” POSTPONE appointment for patient with active lesion. Explain problems of transmission to patient: contagiousness, with possible transmission to other patients; autoinoculation possible from instrumentation that can splash viruses to patient’s eye or extend lesion to the nose. Irritation to the lesion(s) can prolong the course and increase severity of the infection. Prodromal state may be most contagious. Patient is requested to call ahead to change scheduled appointment when it is known that lesion is developing. Treatment: acyclovir, an antiviral drug, has be used in topical, oral, and intravenous forms. It is a selective inhibitor of replication of HSV and is established as the drug of choice for treatment of wide range of herpes virus infections.
- Chickenpox (varicella) and shingles (herpes zoster) are caused by the same virus (varicella-zoster virus-VZV). Chickenpox transmission: highly contagious, may be transmitted by direct contact, droplet (possibly air-borne), or indirect contact with articles soiled by discharge from vesicles and the respiratory tract. Disease process: primarily disease of children, occasionally found in adults not previously exposed. Can be life threatening in children who are immunocompromised (such as those with HIV infection). When primary maternal VZV occurs during pregnancy, fetal infection may result in congenital malformations. Disease is characterized by maculopapular rash that becomes vesicular in a few days, then scabs. Oral lesions may spread to upper respiratory tract. If the itchy, crusty lesions of the skin are scratched, a secondary bacterial infection may occur. Shingles: chickenpox leaves lasting immunity, but the VZV remains latent in the dorsal root ganglia. Reactivation in adulthood may result from immunosuppression (such as drug therapy or HIV infection) and in people with advanced neoplastic disease. Shingles consists of localized UNILATERAL eruptions associated with the nerve endings of the area innervated by the infected sensory nerves. When the second division of the trigeminal nerve is involved, intraoral lesions may occur. EBV: Infectious mononucleosis: generally a disease of adolescents and young adults. Characterized by fever, lymphadenopathy, and sore throat. It is identified by specific atypical lymphocytes called mononucleosis cells. Disease is transmitted orally by direct contact with saliva and by droplet. Viruses are excreted through saliva even when patient is asymptomatic, so there may be long period of communicability or lasting carrier state. Hairy leukoplakia: EBV replicates within epithelial cells, the lesion associated with subsequent development of AIDS. Tongue lesions appear as white linear lesions along the lateral borders.
- HCMV infections are widespread, appear in various forms, with the most severe form developing in infants affected in utero. Transmission and disease effects: virus from mother’s primary or recurrent infection may affect infant in utero, in the birth canal, or through breast milk. CMV in the fetus can lead to premature birth, anemia, mental retardation, microcephaly, motor disabilities, deafness, and chronic liver disease. The virus is excreted in urine, saliva, cervical secretions, and semen. Infection can result from blood transfusion, posttransplant infection, sexual transmission, respiratory droplet (especially among children—children attending daycare centers have a high prevalence of HCMV). Adult infection: symptomatic infection is relatively rare, but infectious “mono” pneumonitis and other infections may be caused by the virus. HCMV, an opportunistic agent, is common cause of both primary and reactivated infections in immunodeficient or immunosuppressed patients, and is a complication of AIDS. Adults also are affected in periapical pathosis with EBV. Prevention: handwashing, personal hygiene, and standard precautions for infection control by HCP. Seropositivity of organ donor assessed before transplant. HLV: widespread distribution among humans; high percentage of population has antibodies. Childhood infection (6 months to 2 years), roseola infantum, with accompanying high temperature and rash. Acts to depress immune system, depletes CD4 lymphocytes, can be cofactor in HIV-AIDS progression. After primary infection, virus persists in latent form. Reactivation can occur after bone marrow transplantation and solid organ transplants, complicated by rejection of the transplant. HHV-7: prevalent in general population, reactivation of latent infection common in the immunocompromised person. Infection may occur following bone marrow and solid organ transplantation. Periodontal connection: gingival tissue may serve as reservoir for HHV-7; high prevalence of HHV-7 detected in both healthy gingiva and diseased periodontal tissues. Kaposi sarcoma-related virus: in immunocompromised host, a major cofactor in production of Kaposi sarcoma, an AIDS-defining lesion.
- Table 4-3
- AIDS is severe pandemic disease caused by infection with the human immunodeficiency virus (HIV-1). HIV-2, isolated in West Africa, and later Europe and North America, has been shown to have similar characteristics and transmission as the original HIV-1. Both are slow, progressive, and often lethal; they have the ability to persist within cells such as macrophages for long periods of time. HIV-1 infected patients may present with symptoms that range from mild abnormalities in immune response with apparent signs to profound immunosuppression association with life-threatening infections and rare malignant conditions. (Terminology related to HIV-1 and AIDS is found in the text, Box 2-2.) Transmission: HIV-1 found in most body fluids; transmission demonstrated via blood, semen, vaginal secretions, and breast milk. Virus has also been found in saliva, tears, urine, and bronchial secretions, but transmission by contact with these fluids has not been described. Sexual contact: virus from infected individual’s blood, semen, or vaginal secretions enters blood circulation through tiny breaks in the rectum, vagina, or penis. Blood and blood products: injection drug users by contaminated shared needles carrying the virus; transfusion of infected blood. Serologic testing of all donor blood has nearly eliminated this threat of transmission. Transplantation of HIV-infected organs and tissues. Occupational accidental exposure injuries. Perinatal virus transmission across the placenta, or during delivery through exposure within the infected genital tract. Postnatal through breast milk. Individuals at high risk of infection: sexually active homosexual and bisexual men having multiple partners without practicing safe sex; users or former users of intravenous drugs, especially when contaminated needles are shared; recipients of blood transfusions or blood products prior to mandatory testing for HIV-1 antibodies in 1985; hemophiliacs and other coagulation disorder patients; male and female prostitutes who do not practice safe sex; HCP who do not adhere to strict barrier procedures and do not follow essential blood-borne precautions; females artificially inseminated with HIV-1-infected semen; recipients of HIV-1-infected organ transplants; steady sexual partners of those previously listed who do not practice safe sex; steady sexual partners of those infected with AIDS or at high risk of AIDS who do not practice safe sex; infants born to HIV-1-infected mothers; infants fed breast milk from HIV-1-infected mothers.