FW: (LML) Skin Smear Services neglected

Leprosy Mailing List – March 5,  2019 Ref.:   (LML) Skin Smear Services neglected From:  Editors LML, Maastricht, the Netherlands Dear colleagues, We have serious worries about the quality (and quantity) of skin smear services in many endemic countries. Several LML authors have been pointing this out in recent months. A common problem for example is the use of the same Ziehl Neelson reagents prepared for tuberculose-staining, for leprosy as well. Ziehl Neelson as used for tuberculosis has a too strong decolouriser. In leprosy the stain should be modified because, M. leprae is a weaker acid-fast mycobacterium. The acid alcohol reagent needs to be adapted. Another approach recommended is the Fite-Faraco Staining Protocol for Leprosy. Not only the staining methodology is important, but also the quality of smears taken. Except that the quality of the skin smear services is questioned, also the number of smears taken in new patients, in differential diagnoses and in follow-up of skin smear positive patients, have been dropped drastically according to some. In the WHO 2011-2015 operational guidelines, SSS was supposed to be done at referral centres. It gives the impression that SSS are mostly negative and not important except for a few early MB cases. It seems that WHO gives a message to countries that SSS are not important for leprosy diagnosis. This is why today country leprosy programme managers don't even talk about SSS. For example: in Liberia and their national referral hospital was doing smears for TB but not for leprosy; in India, the two leprosy control programmes, which were visited by one of us in 2016, were not doing any smears. It is our impression that in many countries SSS are send to TB laboratories and due to wrong staining judged negative. Hence lepromatous patients the infective patients are not diagnosed ergo even high BI patients have a low BI, a self for filling prophesy. We looked into several recent WHO expert committee reports, strategies and guidelines to see what is written about SSS and if these reports reflect on the concerns as laid out in the two previous paragraphs. The WHO expert committee on leprosy: eighth report mentions among others: Since the availability of laboratory facilities for slit skin smear or histopathology is restricted in many endemic countries, and the current PCR technology is still not adequately reliable, diagnosis of most cases of leprosy in the field will continue to be based on clinical evidence, at least for the time being --- page 11. For more WHO expert committee reports see https://www.leprosy-information.org/resource/who-expert-committee-leprosy-eight-report The new Guidelines for the diagnosis, treatment and prevention of leprosy. ISBN: 978 92 9022 638 3 © World Health Organization 2018. World Health Organization. Regional Office for South-East Asia. http://www.who.int/iris/handle/10665/274127. Summary of recommendations diagnosis of leprosy: The guidelines recommend no additional tests in addition to standard methods for diagnosis of leprosy: the diagnosis of leprosy remains based on the presence of only one of three cardinal signs: (i) definite loss of sensation in a pale (hypopigmented) or reddish skin patch; (ii) thickened or enlarged peripheral nerve with loss of sensation and/or weakness of the muscles supplied by that nerve; or (iii) presence of acid-fast bacilli in a slit-skin smear. The clinical diagnosis of early leprosy and PB leprosy can be a challenge. Therefore, a number of serological and other laboratory assays have been developed to supplement clinical diagnostic methods. However, enzyme-linked immunosorbent assays (ELISA) and lateral flow assays are associated with low diagnostic accuracy for PB leprosy. Although some polymerase chain reaction (PCR)-based assays are associated with higher diagnostic accuracy, they lack standardization, are not commercially available, and would be difficult to perform in most primary health-care settings. The guidelines also do not recommend any test for the diagnosis of leprosy in asymptomatic contacts. The predictive accuracy of diagnostic tests for identifying persons who will develop leprosy is low, with poor positive predictive values. LML comments: the use of one cardinal sign (instead of two) is only good enough in the field for multipurpose personnel to make a tentative diagnosis. A leprosy supervisor, medical doctor or leprologist need 2 out of 3 to make the definitive diagnosis. Enhanced Global Strategy for Further Reducing the Disease Burden Due to Leprosy Operational Guidelines (Updated) (2011-2015) Skin smear examination requires a suitably equipped laboratory with staff trained to perform this test. Leprosy skin smear services could be made available in selected units (such as those already doing sputum smears for the diagnosis of TB). In most patients, a skin smear is not essential in the diagnosis of leprosy, but in some cases of early MB leprosy it may be the only conclusive sign of the disease. The majority of people with leprosy have a negative smear If possible, arrange for a skin smear test, especially if there are nodular lesions or if most of the skin is infiltrated with very indistinct lesions and if there is no obvious loss of sensation. These features are more suggestive of multibacillary disease, in which the skin smear is often positive, but some of the other signs, such as loss of sensation, may not be present. A positive skin smear in an untreated individual is diagnostic of leprosy. If there is no loss of sensation in the skin lesions and no enlarged nerves but there are nevertheless suspicious signs, such as nodules or swellings on the face or earlobes, or infiltration of the skin, it is important to try and get a skin smear test done. In these circumstances a positive skin smear confirms the diagnosis of leprosy while a negative result (in the absence of other cardinal signs) would, in practice, rule out leprosy. An alternative diagnosis should then be considered. LML comments to this Enhanced Global Strategy 2011 – 2015 -       TB staff are often not aware that M. leprae needs less decolouration. -       In some regions (e.g. Cebu, the Philippines) the majority of new patients are smear positive. The statement by WHO that the majority of people with leprosy have a negative smear is too general – this depends on the region. -       WHO states that a positive skin smear in an untreated individual is diagnostic of leprosy. That is too general as well – in some cases it could also be TB or NTM. You need another cardinal sign to confirm leprosy! Global Leprosy Strategy 2016–2020 Accelerating towards a leprosy-free world Operational Manual. World Health Organization 2016: Access to laboratory services shall be also ensured because some of the cases may require diagnostic confirmation either through referral of the patient or through transportation of a fixed smear and/or tissue that could be then stained at the laboratory and/or examined by the pathologist. LML strongly feels that the global leprosy programme has lost or diluted its leadership role. It is important to involve a wider group of leprologists from around the world to look for practical solutions. We recommend that 1.    Where ever laboratory services and trained technicians are available SSS should be done; 2.    In doubtful cases, SSS are obligatory and if the slides cannot be processed locally, they should be sent to a referral centre; 3.    In endemic areas, the treatment should be started on the basis of the clinical diagnosis without waiting for the results of the SSS; 4.    Quality control services should be established to ensure reliability of the SSS results. 5.    At the coming Leprosy Congress in the Philippines this topic will need extra attention and a working group set up to improve the SSS services, and also look into the best methods of staining the slides. Best regards, Editors LML LML - S Deepak, B Naafs, S Noto and P Schreuder LML blog link: http://leprosymailinglist.blogspot.it/ Contact: Dr Pieter Schreuder << editorlml@gmail.com

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