Presentation Mv

SPECIMEN COLLECTION FOR MEASLES VIRUS ISOLATION

Eshetu Lemma BSc (MLT), BA (Econ)

Measles Lab Data Manager

INTRODUCTION Virus isolate are extremely important for molecular epidemiologic surveillance to help determine the geographic origin of the virus and the viral strain circulate Isolation of measles virus is not recommended as a routine method to diagnosis measles Measles virus can be isolated from nasopharyngeal aspirate or swab, throat swab, blood, and urine Clinical specimen for viral isolation should be collected at the same time as samples taken for serologic testing

MV is more likely to be isolated when the specimens are MV collected within 4 days of rash onset Collection of specimens for virus isolation should not be Collection delayed until serologic confirmation is obtained Throat and nasopharyngeal specimens can be collected Throat – in order of increasing virus yield -by aspiration -by lavage -by swabbing of the mucous membranes The sensitivity of nasal swabs is comparable to that of The nasopharyngeal aspirates for detection measles virus

Types of Specimens - nasopharyngeal aspirate - nasopharyngeal swab - nasal wash - throat swab - urine Materials Requires - gloves and mask - sterile dry swab - tongue depressor

Cont... - suction devices (syringe, vacuum pump or wall suction) - specimen trap - catheter -sterile saline or culture media - Viral transport medium (VTM): sterile, usually consisting of Hanks balanced salt solution and antibiotics to reduce bacterial contamination growth - ice bag - investigation form - labeling material

 Nasopharyngeal Swab Collection 1. When you collect the specimens, wear gloves and a mask 2. If the patient has a lot of mucus in the nose, this can interfere with the collection of cells. Either ask the patients to use a tissue to gently clean out visible nasal mucus or clean the nostril yourself 3. Prior to insertion, measure the distance from the corner of the nose to the front of ear and insert the shaft only half this length

Cont... 4. Seat the patient comfortably. Tile the patient's head back slightly to straighten the passage from the front of the nose to the nasopharynx to make insertion of the swab easier 5. Using a swab with a flexible shaft gently insert the swab along medial part of the septum, along the base of the nose, until it reaches the posterior nares

Cont... 6. Then gentle rotation of the swab may be helpful 7. Rotate the swab several times to dislodge the columnar epithelial cells 8. Withdraw the swab and place it in VTM or the collection tube with Saline or culture media (squeeze bottom of the tube to release media)

9. Snap the end of the swab to make it fit more easily 10. Seal the tube. Label the specimen with patient's name, date of specimen collection and type of specimen

Cont... 11. Specimens should be shipped on wet ice at 4-80c and should arrive at the national measles laboratory within 48 hours Fig.1 Nasopharyngeal Swab Collection

Throat Swab Collection Method Throat 1. Do not obtain throat samples if epiglottis is inflamed, as sampling may cause serious respiratory obstruction 2. Depress tongue gently with tongue depressor 3. Extend sterile swab between the tonsillar pillars and behind the uvula. (Avoid touching the cheeks, tongue, uvula or lips) 4. Sweep the swab back and forth across the posterior pharynx, tonsillar area and any inflamed or ulcerated areas to obtain sample

Cont... 5. Withdraw the swab and place it in VTM or the collection tube with Saline or culture media 6. Snap the end of the swab to make it fit more easily 7. Seal the tube. Label the specimen with patient's name, date of specimen collection and type of specimen VTM Swab

Sponge containing VTM

Nasopharyngeal Aspiration 1. Prepare a suction devices (syringe, vacuum pump, or wall suction), specimen trap and catheter 2. Insert catheter nasally into posterior nasopharynx 3. Apply suction as catheter is slowly withdrawn 4. If sample has been aspirated into a syringe seal the end of the aspiration tube and send specimen in syringe 5. Place sample in transport medium into sterile transport vial 6. Ensure that the top of the vial is screwed on securely

Cont... 7. Label with patient name, date of birth, sample type and date of collection 8. Then specimens should be shipped on wet ice at 4-80c and should arrive at the national measles laboratory within 48 hours

 Urine Collection Method 1. First morning voided specimens are ideal, but any urine collection is adequate. 2. Collect 10-50 ml of urine in a urine specimen container 3. After collection, keep the specimen cool (refrigerator or wet ice) 4. If centrifugation is not available, do not freeze the urine sample. The entire urine specimen should be stored at 4° C, and shipped to the measles lab on cold packs.

Cont... 5. Most urine collection cups are not leakproof. Transfer the urine to sterile plastic centrifuge tubes

6. After collection, keep the specimen cool (refrigerator or wet ice). It is best to centrifuge the urine specimen as soon after collection as possible

7. If facilities are available, centrifuge the urine at 400 x g for 10 minutes at 4° C to pellet the sediment

Cont... 8. Re-suspend the sediment in 2 ml of VTM or any cell culture medium and ship 9. Preferably, specimens that have been centrifuged and re-suspended should be frozen at -70° C and shipped on dry ice 10. If dry ice is not available, however, they can be stored at 4° C and shipped on cold packs

Activates of NML: Key Notes  Lab. is established the isolation of measles virus from clinical samples 29 Samples were collected from 2006-08, only five were positive MV, 3 isolates were sent to RRL : B3 Publication , Genetic characterization & progression of B3 measles genotype in Ethiopia: EMJ, V 46, No.1, 2008)

CONCLUSION For practical purpose, Ethiopian case, the best or choice of specimen for MV isolation is nasopharyngeal swab, nasal swab, throat swab and urine in order of decreasing virus yield Samples for MV isolation, should be within or less than 5 days after onset of rash Variables on the investigation form including name, age, date of onset, type of specimen, etc should be filled properly If the type of specimen is urine, don't centrifuge with ordinary centrifuge which doesn't hold -40c, rather send it to national measles lab. at refrigerator temp (4-80c).

Cont...  At least 5 samples should be collected from separate chains of transmission  Some of samples were not good such as contamination, inappropriate collection  Measles virus isolation will be done only for outbreak measles case  Call to notify national measles lab. of specimen being delivered through phone number (+251 011 277 84 80 or 277 84 77)  If immediate cold shipment can not be arranged, call the national measles lab. to determine the best method to handle the specimen

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