Ebola primary prevention

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Michael Maddaleni, B.S.; Guillermo Rodriguez Nava, M.D. [2]

Overview

Transmission of ebola virus disease has only been documented to occur during the symptomatic phase but not during the incubation period. If transmission of ebola occurs, steps need to be taken to prevent further infection as well as transmission to other people. It is important to be able to prevent subsequent transmission of ebola. Transmission of ebola can be prevented by isolation of patient, wearing a HEPA or other biosafety mask and by limiting the movement of the patient from the room to other areas.

Primary Prevention in the USA

Risk Categories

• VHF should be suspected in febrile persons who, within 3 weeks before onset of fever, have either:

1. Traveled in the specific local area of a country where VHF has recently occurred.
2. Had direct unprotected contact with blood, other body fluids, secretions, or excretions of a person or animal with VHF.
3. Had a possible exposure when working in a laboratory that handles hemorrhagic fever viruses

• The likelihood of acquiring VHF is considered low in persons who do not meet any of these criteria. Even following travel to areas where VHF has occurred, persons with fever are more likely to have infectious diseases other than VHF.
• Clinicians should promptly evaluate and treat patients for these more common infections while awaiting confirmation of a VHF diagnosis.

Infection Control Precautions

The following recommendations should be followed when caring for persons with suspected VHF:

• Patients who are hospitalized or treated in an outpatient healthcare setting should be placed in a private room and Standard, Contact, and Droplet Precautions should be initiated.. Patients with respiratory symptoms also should wear a face mask to contain respiratory droplets prior to placement in their hospital or examination room and during transport.
• Caretakers should use barrier precautions to prevent skin or mucous membrane exposure of the eyes, nose, and mouth with patient blood, other body fluids, secretions (including respiratory droplets), or excretions. All persons entering the patient's room should wear gloves and gowns to prevent contact with items or environmental surfaces that may be soiled. In addition, face shields or surgical masks and eye protection (e.g., goggles or eyeglasses with side shields) should be worn by persons coming within approximately 3 feet of the patient.
• Additional barriers may be needed depending on the likelihood and magnitude of contact with body fluids. For example, if copious amounts of blood, other body fluids, vomit, or feces are present in the environment, plastic apron, leg, and shoe coverings also may be needed.
• Nonessential staff and visitors should be restricted from entering the room of patients with suspected VHF. Maintain a log of persons entering the patient’s room.
• Before exiting the room of a patient with suspected VHF, safely remove and dispose of all protective gear, and clean and disinfect shoes that are soiled with body fluids as described in the section on environmental infection control below.
• To prevent percutaneous injuries, needles and other sharps should be used and disposed of in accordance with recommendations for Standard Precautions.
• If the patient requires a surgical or obstetric procedure, consult your state health department and CDC regarding appropriate precautions for these invasive procedures.
• Although transmission by the airborne route has not been established, hospitals may choose to use Airborne Precautions for patients with suspected VHF who have severe pulmonary involvement or who undergo procedures that stimulate coughing and promote the generation of aerosols (e.g. aerosolized or nebulized medication administration, diagnostic sputum induction, bronchoscopy, airway suctioning, endotracheal intubation, positive pressure ventilation via face mask [e.g., biphasic intermittent positive airway pressure ventilation, continuous positive airway pressure ventilation], and high frequency oscillatory ventilation) to prevent possible exposure to airborne particles that may contain virus.

Environmental Infection Control Procedures

• Environmental surfaces or inanimate objects contaminated with blood, other body fluids, secretions, or excretions should be cleaned and disinfected using standard procedures.
• Disinfection can be accomplished using a approved disinfectant or a 1:100 dilution of household bleach (1/4 cup bleach to 1 gallon water). For grossly soiled surfaces, (e.g., vomitus or stool), use a 1:10 dilution of household bleach.
• Soiled linens should be placed in clearly labeled leak-proof bags at the site of use, transported directly to the laundry area, and laundered following routine healthcare laundry procedures.
• Liquid medical waste such as feces and vomitus can be disposed of in the sanitary sewer following local sewage disposal requirements. Care should be taken to avoid splashing when disposing of these materials.

Handling of Human Remains

• If the patient dies, handling of the body should be minimized. The remains should not be embalmed. Remains should be wrapped in sealed leak-proof material and cremated or buried promptly in a sealed casket. If an autopsy is necessary, the state health department and CDC should be consulted regarding appropriate precautions.

Management of Exposures

• Persons with percutaneous or mucocutaneous exposures to blood, body fluids, secretions, or excretions from a patient with suspected VHF should immediately wash the affected skin surfaces with soap and water. Mucous membranes (e.g., conjunctiva) should be irrigated with copious amounts of water or eyewash solution. Exposed persons should receive medical evaluation and follow-up care, including fever monitoring twice daily for 21 days after exposure. Consultation with an infectious diseases expert is recommended for exposed persons who develop fever within 21 days of exposure.

Primary Prevention in Endemic Areas

Use Standard Precautions

A patient with a virus hemorrhagic fever (VHF) may come to the health facility at any point in his or her illness:

• When the possibility of exposure is often highest, and
• Before the specific cause of the patient’s illness is known.

Because a health worker cannot always know when a patient’s body fluids are infectious. Standard Precautions should be used with all patients in the health care setting, regardless of their infection status. Standard Precautions are designed to prevent unprotected contact between the health care worker and:

• Blood and all body fluids whether or not they contain blood
• Mucous membranes.

When a specific diagnosis is made, additional precautions are taken, based on how the disease is transmitted.

Establish and Maintain a Minimum Level of Standard Precautions

Limited supplies and resources may prevent a health facility from using all the Standard Precautions all the time. However, health facilities should establish and maintain a basic, practical level of Standard Precautions that can be used routinely with patients in their health facility. At a minimum, consider the services in the health facility that present a risk of disease transmission due to potential contact with blood and all body fluids, broken skin or mucous membranes. For health facility staff who work in such areas, establish at least:

• A source of clean water.
• Routine handwashing before and after any contact with a patient who has fever.
• Safe handling and disposal of sharp instruments and equipment, including needles and syringes.

Establish Routine Handwashing

Handwashing is the most important precaution for the prevention of infections. Handwashing before and after contact with a patient who has fever should be a routine practice in the health facility even when VHF is not present. Washing hands with soap and water eliminates microorganisms from the skin and hands. This provides some protection against transmission of VHF and other diseases. In services where health care workers see patients with fever, provide at least:

• Cake soap cut into small pieces.
• Soap dishes. Microorganisms grow and multiply in humidity and standing water. If cake soap is used, provide soap dishes with openings that allow water to drain away.
• Running water, or a bucket kept full with clean water.
• A bucket for collecting rinse water and a ladle for dipping, if running water is not available.
• One-use towels. Sharing towels can result in contamination. Use paper towels. If they are not available, provide cloth towels that can be used once and then laundered. If towels are not available, health care workers and health facility staff can air-dry their hands.

Make sure health facility staff know the steps of handwashing:

1. Place a piece of soap in the palm of one hand.
2. Wash the opposite hand and forearm. Rub the surfaces vigorously for at least 10 seconds. Move soap to the opposite hand and repeat.
3. Use clean water to rinse both hands and then the forearms. If running water is not available, pour clean water from a bucket over the soapy hands and forearms. The rinse water should drain into another bucket.
4. Dry the hands and forearms with a clean, one-use towel. First dry the hands and then the forearms. Or let rinsed hands and forearms air-dry.

Handle and Dispose of Sharp Instruments Safely

• Disease transmission can occur through accidental needlestick injuries. Make sure health facility staff always handle sharp instruments safely. Do not recap needles after use.
• Limit invasive procedures to reduce the number of injectable medications. This will limit the opportunities for accidental needlestick injuries.
• When an injection is necessary, always use a sterile needle and sterile syringe for each injection.
• To discard disposable needles and syringes safely: Disposable needles and syringes should be used only once. Discard the used disposable needle and syringe in a puncture-resistant container. Then burn the container in an incinerator or pit for burning.
• If puncture-resistant containers are not available, use empty water, oil, or bleach bottles made with plastic or other burnable material. Adapt them for use as puncture-resistant containers.

Disinfect Reusable Needles and Syringes Safely

• Reusable needles and syringes are not recommended. If reusable needles and syringes are used, clean, disinfect and sterilize them before reuse, according to your hospital’s policy.
• Needles and syringes used with VHF patients require special care. Cleaning staff should wear two pairs of gloves when handling needles and syringes used with any patient with a known or suspected VHF.

Disinfect Disposable Needles and Syringes That Must Be Reused

• Whenever possible, use disposable needles and syringes only once and then discard them safely.
• In situations when disposable needles and syringes must be reused, make sure they are cleaned and disinfected after each use. Disinfection with bleach will reduce the risk of transmission of VHF and blood-borne diseases, such as HIV infection and viral hepatitis.

1. Obtain a jar or pan. Clean and disinfect it.
2. Place the disposable needle and syringe in a pan of soapy water after use. Fill the needle and syringe with soapy water. Leave them to soak until they are cleaned.
3. Take the soaking needles and syringes to the cleaning area.
4. Clean them very carefully in soap and water. Remove any blood or other biological waste, especially from the area around the syringe fittings. Blood or other biological products may collect in these small openings.
5. Draw full-strength bleach into the needle and syringe.
6. Soak for 30 seconds, and then expel bleach into a container for contaminated waste.
7. Soak again by once more drawing full-strength bleach into the needle and syringe. Soak for 30 seconds, and then expel bleach into the container for contaminated waste.
8. Let the disinfected needle and syringe air-dry. Store them in a clean jar or pan that has been disinfected.

Use VHF Isolation Precautions

• Isolate the patient.
• Wear protective clothing in the isolation area, in the cleaning and laundry areas and in the laboratory. Wear a scrub suit, gown, apron, two pairs of gloves, mask, headcover, eyewear, and rubber boots.
• Clean and disinfect spills, waste, and reusable equipment safely.
• Clean and disinfect soiled linens and laundry safely.
• Use safe disposal methods for non-reusable supplies and infectious waste.
• Provide information about the risk of VHF transmission to health facility staff. Reinforce use of VHF Isolation Precautions with all health facility staff.
• Provide information to families and the community about prevention of VHFs and care of patients.

Cleaning

• Environmental surfaces or objects contaminated with blood, other body fluids, secretions or excretions should be cleaned and disinfected using standard hospital detergents/disinfectants. Application of disinfectant should be preceded by cleaning.
• Do not spray (i.e. fog) occupied or unoccupied clinical areas with disinfectant. This is a potentially dangerous practice that has no proven disease control benefit.
• Wear gloves, gown and closed shoes (e.g. boots) when cleaning the environment and handling infectious waste. Cleaning heavily soiled surfaces (e.g. soiled with vomit or blood) increases the risk of splashes. On these occasions, facial protection should be worn in addition to gloves, gown and closed, resistant shoes.
• Soiled linen should be placed in clearly-labelled, leak-proof bags or buckets at the site of use and the container surfaces should be disinfected (using an effective disinfectant) before removal from the site. Linen should be transported directly to the laundry area and laundered promptly with water and detergent. For low-temperature laundering, wash linen with detergent and water, rinse and then soak in 0.05% chlorine for approximately 30 minutes. Linen should then be dried according to routine standards and procedures.
• Linen that has been used by HF patients can be heavily contaminated with body fluids (e.g. blood, vomit) and splashes may result during handling. When handling soiled linen from HF patients, use gloves, gown, closed shoes and facial protection.
• If safe cleaning and disinfection of heavily soiled linen is not possible or reliable, it may be prudent to burn the linen to avoid any unnecessary risks to individuals handling these items.

Post-mortem examinations

• Post-mortem examination of HF-patient remains should be limited to essential evaluations only and should be performed by trained personnel.
• Personnel examining remains should wear eye protection, mask, gloves and gowns as recommended for patient care.
• In addition, personnel performing autopsies of known or suspected HF patients should wear a particulate respirator and eye protection or face shield, or a powered air purifying respirator (PAPR).
• When removing protective equipment, avoid any contact between soiled gloves or equipment and the face (i.e. eyes, nose or mouth).
• Hand hygiene should be performed immediately following the removal of protective equipment used during post-mortem examination and that may have come into contact with potentially contaminated surfaces.
• Place specimens in clearly-labelled, non-glass, leak-proof containers and deliver directly to designated specimen handling areas.
• All external surfaces of specimen containers should be thoroughly disinfected (using an effective disinfectant) prior to transport.
• Tissue or body fluids for disposal should be carefully placed in clearly marked, sealed containers for incineration.

Movement and burial of human remains

• The handling of human remains should be kept to a minimum. The following recommendations should be adhered to in principle, but may need some adaptation to take account of cultural and religious concerns:
  • Remains should not be sprayed, washed or embalmed.
  • Only trained personnel should handle remains during the outbreak.
  • Personnel handling remains should wear personal protective equipment (gloves, gowns, apron, surgical masks and eye protection) and closed shoes.
  • Protective equipment is not required for individuals driving or riding a vehicle to collect human remains.
  • Protective equipment should be put on at the site of collection of human remains and worn during the process of collection and placement in a body bag.
  • Protective equipment should be removed immediately after remains have been placed in a body bag and then placed inside a coffin.
  • Remains should be wrapped in sealed, leak-proof material and should be buried promptly.

Other Transmission-Based Precautions

Airborne Transmission

1. Place the patient in an isolation room that is not air-conditioned or where air is not circulated to the rest of the health facility. Make sure the room has a door that can be closed.
2. Wear a HEPA or other biosafety mask when working with the patient and in the patient's room.
3. Limit movement of the patient from the room to other areas. Place a surgical mask on the patient who must be moved.

Droplet Transmission

1. Place the patient in an isolation room.
2. Wear a HEPA or other biosafety mask when working with the [[patient.
3. Limit movement of the patient from the room to other areas. If patient must be moved, place a surgical mask on the patient.

Vaccination

Vaccines have been produced for both Ebola and Marburg that were 99% effective in protecting a group of monkeys from the disease. These vaccines are based on either a recombinant Vesicular stomatitis virus or a recombinant Adenovirus carrying the Ebola spikeprotein on its surface. Early human vaccine efforts, like the one at NIAID in 2003, have so far not reported any successes. The biggest problem with the vaccine is that unless the patient is given it near the onset of the virus (1-4 days after the symptoms begin) then there will be too much damage to the human body to repair, ie: ruptured arteries and capillaries, vomiting, and other symptoms which may still cause enough harm to kill or seriously traumatize the patient.