Leprosy Mailing List – September 7, 2019
Ref.: (LML) Microscopy as the gold standard
From: Joel Almeida, London and Mumbai
Contributions from Dr. Gelber and Dr. Saunderson (LML "Leprosy Diagnosis and Treatment, Sept 4 and 6, 2019) underline the importance of bacilloscopy of slit skin smears to recognise and classify LL patients correctly, or at all.
Without skin smears it is easy to miss LL patients altogether, as illustrated by the Salaunikhurd experience in India (1, 2). These patients in the early stages can show no clear enlargement of nerves, no anaesthesia, and no clearly defined skin lesions. Without skin smears, neither they nor even trained staff reliably can recognise LL disease.
The outcome was that the case detection rate in such a neighbourhood increased from 30/10,000 persons/year to over 100/10,000 persons/yr, within 2 or 3 years, with multiple patients in even a single household. When this happens among people with low and uncertain income, migration in search of work is highly probable. This can spread as many as tens of millions of viable bacilli per day, wherever these untreated patients are forced to go in search of work for survival. The lack of skin smears can undo all our other good work. This is one of the central reasons why the disease has continued to spread during the past two decades.
Fortunately, after the Indian authorities received the LML message, the official public education materials have started including not only skin patches but also skin nodules on the ear as a sign of disease. The Indian program is taking steps also to upgrade skin smear services, and these measures are very important. It would be good to encourage and applaud such improvements at the front-lines.
As for TB and malaria, the CDC in the USA considers microscopy (with culture for TB) as the gold standard for diagnosis. (3, 4) This is not due to lack of expertise or finance, but because direct visualisation of the infectious agent is incontrovertible evidence with high prognostic value.
It would be good to keep spreading the word that skin smears are highly important if we are to recognise LL disease and respond appropriately. Zero transmission is not inevitable. Salaunikhurd showed that increased transmission is highly possible if we fail to recognise LL disease. Wenshan/Yunnan showed that failure to provide prolonged protection to LL patients can ensure continued transmission (5). Failure correctly to classify LL patients can ruin our efforts to even control the disease, let alone achieve zero transmission. Further, the use of single drugs for treatment or chemoprophylaxis multiplies the risk of MDR bacilli, thereby multiplying the risk of increased transmission.
We need to get the science right, because it is like the eyes for our efforts. We cannot afford to walk with our eyes closed, along the precipice of MDR bacilli. Zero transmission is possible, but only if we keep carefully tying together all the clues from the front-lines.
1) Central Leprosy Division, India. Epidemiological investigation of multiple cases occurring in one family in village Salaunikhurd. NLEP newsletter Vol III, Issue 3, July – Sept 2018
2) Missed lepromatous cases. LML 6 Jan 2019.
3) CDC, USA. TB testing and diagnosis.
4) CDC, USA. Malaria - diagnostic tests.
5) Interruption of transmission - post-MDT chemoprophylaxis for LL patients. LML 22 June 2019.
LML - S Deepak, B Naafs, S Noto and P Schreuder
LML blog link: http://leprosymailinglist.blogspot.it/
Contact: Dr Pieter Schreuder << email@example.com
You received this message because you are subscribed to the Google Groups "Leprosy Mailing List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to firstname.lastname@example.org.
To view this discussion on the web, visit https://groups.google.com/d/msgid/leprosymailinglist/7653e728-a0df-406a-b1b9-3732497d63f9%40googlegroups.com.