Introduction
Ebola comes from filoviridae family of virus called filovirus.Ebola virusis a lipid enveloped filo virus. Usually, they have long filamentous structure sometimes branched or in the shape of ‘6’ or ‘u’ with length usually between 800-1000nanometer (which can reach up to 14000 nanometers due to concatemerization). It may have diameter of approx. 80 nanometer diameter [1], [2].Ebola virus disease (EVD) was also known as Ebola hemorrhagic fever (EHF) [3].
The primary sources of Ebola virus are believed to be Fruit bats or primates (apes, monkeys).Depending upon risk related to biological contaminants, European directive 2000/54/EEC categorized them into 4 categories, where 1 indicates lowest risk and 4 indicates highest risk. The infection caused by Ebola virus is severe and can often causefatal illness. Ebola is listed as risk 4 pathogen by WHO considering the high death rate(up to 90%) associated with the disease [4]. Ebola virus can spread from human-animal, human – human contacts. The infection can spread by eating infected food items, by direct contact with infected human or animal body fluids, through blood and other body fluids (breast milk, urine, feces, sweat, tear, semen, amniotic fluid (probable), mucous membrane / respiratory secretions (saliva, vomit, sneeze, cough, spit, vaginal secretions), diahorea, peritoneal fluid, cerebrospinal fluid, synovial fluid,etc [5]. It can spread by punctures (caused by infected needles, blades); sprays (i.e. aerosols, sneeze etc); rashes, abrasions on skin. Ebola viruses can also get entry through mucosal tissues s0uch as eyes, nose, mouth, vagina, etc. Virus may also spread with contaminated surfaces. Ebola virus does not spread through air [3], [6], [7].
Person infected with Ebola virus can show symptoms of infection such as hemorrhagic fever higher than 38.3oC, muscle and joint pain, vomiting, diarrhoea, abdominal pain, severe headache, intense weakness andtiredness. It can damage the functionally of liver, kidney and vascular system. The damage to the later system can lead to severe bleeding from organs (external and internal)and under the skin. Death occurs due to low blood pressure and dehydration. Survivors may suffer from joint pains, hearing loss, etc.The Ebola virus disease (EVD) can cause symptoms within 2 to 21 days of infection [1], [3], [7]. Ebola virus infected bodies can remain contagious for up to 60 days [3]. It remains for a long time in t semen, breast milks in case of recovery. The virus can survive for several days in liquid or dried material at room temperature [3].
Like EVD, there are other diseases such as Severe Acute Respiratory Syndrome (SARS) is caused by different virus called SARS coronavirus. The coronavirus are RNA viruses with large, enveloped, positive sense single stranded structure. They are classed as one of the largest RNA viruses known to humans with length between 27 to 32kb (29700 nucleotides) and 100-140 nanometer diameters [8]. It is a respiratory disease with initially flue like symptoms, which later on can develop into either direct viral pneumonia or secondary bacterial pneumonia, respiratory failure, liver failure, heat failure, etc [9]. SARS were found in dogs, ferret badgers, palm civets, cats as well as in bats with or without clinical signs. There is no safe cure, vaccines or antibiotics available. The patient must be isolated into a negative pressure room and the healthcare worker must wear full personal protective material as barrier for protection of the full body. Similar to Ebola, SARS spreads through cough, sneeze, talks, infected droplets, etc. through mucous membranes or by touching infected surfaces, objects etc. The death rate in SARS infected people above the age of 60 years is as high as 50%. In 2003, SARS had crossed boundaries and spread across two dozen countries.
As discussed earlier about EVD and SARS, another virus borne disease is Avian flu. Most avian flu viruses do not infect humans, but few such as H5N1, H7N9 have caused serious infections in humans. Aviation flu is another family of virus, which spreads to humans either by handling dead infected birds (mainly through poultries) or from contact with infected fluids. Symptoms of avian flu can be high fever and influenza like symptoms (cough, sore throat), diarrhea, vomiting, pain in abdomen and chest, bleeding from nose, gums etc [10].multiple organ dysfunction etc. The name of avian flu includes two protein name letters, where H represents Hemagglutinin protein and N represents Neuraminidase protein.
Considering the severity of above diseases, all the associated professionals such as health care professionals / support staff/ co-workers, mortuary/death workers, emergency responders, patient, doffing donning observers, deployed Ebola responders, waste and water cleaning workers, humanitarian aid workers, college / University workers / researchers, airlines and other travel industry personnel and laboratory workers can be at most risk of coming in contact with infected patient fluids and get infected [11], [12]. Hence, the role of Personal Protective Equipment (PPEs) is very critical for healthcare as well as associated non health care workers.
Personal protective garments
PPEs are used as [13], [14]Barrier against infectious contaminated objects
• Effective filter for the infectious contaminated objects
• Barrier to stop cross contamination spread through various infections such as nosocomial infections, human fluid contaminants such as blood, perspiration, saliva, omit, semen, feces, urine and skin cells
Transmission of microorganisms through PPEs depends upon various factors such as [15].
1. Pore size (filtering capacity) of PPE
2. Thickness of PPE
3. Repellency of PPE
4. Morphology, size, shape and, adaptation of environment.
5. Surface tension, volume, viscosity and force
6. Physical, thermal, chemical and environmental stresses.
7. Type of carriers (body fluids, sloughed skin cells, lint, dust, respiratory droplets and aerosolized molecules.
WHO, CDC and ECDC have listed the number of PPEs and also suggested steps and procedures for donning and doffing of those PPEs in detail. The lists of PPEs specific to occupation and role, task of healthcare or non-healthcare personnel dealing with EVD are suggested in (Appendix 3, 4, 5) .The important f[16]–[18]actors to be considered as a guideline in designing PPE are as listed below [13], [14], [19], [20].
The amount of force by which the contaminated objects can pass through or get filtered (such as in case of sneeze, blood droplets or blood volume with force, vomit particles, coughing, diarrhea,etc)
o The size of the contaminated objects (i.e. virus, bacteria, fungi, large droplets, aerosols, fluids etc) [21][22].
• Sneeze can generate respiratory infectious particles containing biological organisms in the form of droplet nuclei of 0.5 to 12.0 µm in size
• The sizes of various organisms are as given
Hepatitis B virus- 0.04µ-0.07µ, Filoviruses (Ebola)- 0.08 µ diameter and 0.79-0.97 µm length In general, viruses (0.02 µ to 0.3 µ), bacterial cells and spores (0.3 to 10 µ), fungal spores (2 to 5 µ)
o The type of organs to be protected (eye, nose, mouth, body)
o The exposure time ( Short, medium, long)
o The amount of contaminated objects ( droplet, large volume)
o The mechanical strength ( Puncture resistance, abrasion strength, tensile strength, tear strength, bursting strength)
o End user objective (patient, health care worker, doctors, nurses etc)
o Physical conditions of contaminated object (wet, dry)
o Type of procedure (sterile, non-sterile)
o Severity of disease level (level1, level 2 etc.) or degree of protection required
o Type of surgery (invasive or non-invasive)
o Environmental impact
o weight and surface thickness
o electrostatic properties
o Ease of disposing off, (disposable, non-disposable) or washing requirements
o Cost(related to wash, transportation, energy, people involved for working – manufacturing, disposal etc)
o Waste management
o Some physical characteristics (odor, absorbency, flammability, porosity and linting ability)
o Drapability and feel sensation (eg bare hand and hand with gloves has different sensations)
o Size and skin fitting to end user
o Skin irritation / sensitivity, biocompatibility, comfort factor (breathability, temperature, RH, air circulation)
o Psychological effect for color of PPEs – black color is not acceptable in some community. Moreover, light color is more preferred over dark to easily recognize any dust, dirt contamination, design and shape ( ease of wearing or acceptance of dress code in particular region religion, gender , light reflectance, odour etc)
o Storage, transportation, packaging conditions and liability issues
o Seam, any stich joint, any closures, zips of each PPE must not be an entry point for any contaminated object.
o It is also important that the closures, zip of each PPE must be checked.
o Change in PPE in properties (barrier mechanical etc) after each processes such as wash , sterilization
The performance of PPE may change/deteriorate with different conditions such as sterilization, washing cycle, storage time and condition, physical/thermal/chemical stresses, so it is advisable to test any PPE after passing through the above conditions. Broadly recommended PPE [5], [23]–[25] for EVD infectious diseases should be considered as guideline only, as there is no well-established list of PPE available. It is getting updated by various agencies from time to time. Various agencies, industries have suggested guidelines for PPEs against EVD. OSHA recommends employers to follow OSHA standards on blood borne pathogens (29 CFR 1910.1030), PPE (89CFR 1910.132), respiratory protection (29 CFR 1910.134). OSHA also published PPE selection matrix for people getting effected due to occupational exposure to EVD [26]. Different agencies classified PPEs as per performance requirement. In general, the recommended PPEs for protection against disease such as EVD are as follows
o Eye and face protection
o Fluid resistant mask or respirator
o Impermeable gloves
o Protective clothing
o Impermeable foot wear
Eye, face protection / Head covers
PPE such as goggles, face shield, fluid resistant head cover must cover from hair to head, neck including all mucous membranes (such as eyes, mouth, nose) for the protection against infectious agents. Head covers separate from gown or coveralls are preferred for easy removal [5], [27]. Eye protection is necessary against hazards such as splashes, sprays and respiratory droplets. Face shield with crown and chin protection extended upto ear are recommended [25].The hair, face and neck must be covered with suitable mask / respirator, full face shield helmet or head piece covered with disposable hood, which can cover the neck and extend up to shoulders.
Goggles are recommended over safety glasses for infectious conditions. Indirectly vented or nonvented goggles are preferred over directly vented goggles to protect against splashes, sprays and droplets [25]. Eye and face protection: must have better visibility, fogging and scratch resistance. They must be worn in addition to the respirator / masks. Face shield can provide protection to eyes as well as other areas of faces. Goggles are preferred over safety glasses as the impact protection of safety glass against splashes or droplets is low compared to goggles [25]. Goggles and face shield quality can be as per EU standard directives 86/686/EEC, EN166/2002 or ANSI/ISEA-Z87.1-2010 or equivalent.
Recommended technical specifications / properties for level 1 and level 2 goggles for EVD [5], [27], [28] are given below. Goggles level 1 and level 2 are classified as per guidelines given in [28]:
o Disposable
o Single use
o Latex free
o Good seal with the skin of the face
o Adjustable straps to facilitate good fit
o Flexible frame to easily fit ll face contours without too much pressure
o Covers the eyes and surrounding areas and accommodates for prescription glasses
o Indirect venting to reduce fogging
o No or covered ventilation opening preferred
o Fog and scratch resistant
o Anti-mist spray may be applied prior to donning the goggles
o Goggles are not required if the face shield provides complete coverage of sides and length of the face
o Cover the eyes completely
o Good seal with face skin.
o Provide easy accommodation of any prescription glasses
o Easy to wear and adjust / fit to all face shapes
o Must be too tight or else it might become loose.
o Provide good visibility
o Fog and scratch resistant
Level 1 & level 2 goggles quality can comply withEU standard directive 86/686/EEC, EN 166/2002 or equivalent [28].
Recommended technical specifications / properties for Face shield Level 1 & level 2 PPE for EVD. (Face shield level 1 and level 2 are classified as per guidelines given in [28]):
o Disposable
o Single use
o Latex free
o Made of clear plastic
o Provides for good visibility to the wearer and the patient
o Minimizes glare
o Fog resistant
o Adjustable straps/harness to facilitate good fit
o Fog resistant material
o Easy fit and firm fitting of face shield
o Cover whole face length and sides – Complete coverage of sides and length of the face preferable and if this can be achieved, then goggles are not required.
Face shield Level 1 & level 2 PPE quality can comply with [28]
o EU standard directive 86/686/EEC, EN 166/2002 or equivalent
o ANSI / ISEA Z87.1-2010
o Face shield visor with chin guard to confirm to EN166.1.B.3.9
An inner mask may be used to separate the nose and mouth from the eye (visor) area(s) of the full face mask.
Recommended technical specifications for hood level 2 for EVD. Hood level 2 are classified as per guideline given in [28]:
o Disposable
o Single use
o Latex free
o Soft and breathable
o Covers neck and shoulders reaching upper part of gown /coverall
o Facial opening constructed without elastic behavior
o Availability of different sizes
o Preferably fluid resistant
o Preferably sealed /protected seams