Leprosy Mailing List – April 23, 2023
Ref.: (LML) Why we can be optimistic about Brazil
From: Joel Almeida, Mumbai, India
Dear Pieter and colleagues,
Congratulations to the Sasakawa Health Foundation on its Bulletin amplifying the voices of people affected and professionals from endemic countries. Their abilities, talents and efforts need not be marginalised. Instead, they could usefully be empowered as the main engines of change and improved impact, whose quiet efforts have so far produced the world's best epidemiological impacts (1-4). It is projects with big epidemiological impact that usefully could be held up as the world leaders, worth emulating. Advances in knowledge and technology remain important, but existing knowledge and technology deserve full exploitation. Much more is achievable than is widely achieved currently.
Brazil is depicted as having failed to eliminate HD (leprosy) as a public health problem. This is potentially a blessing to Brazil. Once something is proclaimed to be a non-problem, it is easily forgotten. Therefore, Brazil might be glad that HD is still recognised as a problem.
Why has Brazil experienced unusual difficulty in reducing transmission? Even in states such as Tocantins where single dose rifampicin was tried and found lacking in impact? Could it be because Brazil is one of the few countries that largely lacked prolonged MDT (multi-drug therapy)? From the very outset MDT in Brazil was shortened for even LL (lepromatous) patients, to only 24 months or 12 months. The globally fashionable practice of withdrawing anti-microbial protection from even LL patients in endemic areas demonstrably has resulted in 1 child being newly infected for each 2.4 reinfected cases among adults in a part of Brazil (5). Such fashionable abandonment of human beings to the bacilli is contrary to all the noble values of our community. The consequences are being borne by the people of Brazil and other endemic countries. It is unnecessary.
In India too, the northern states largely lacked prolonged MDT. Shortly after they gained access to MDT, the duration was shortened to only 12 months for even LL patients. Those unfortunate Indian states are still struggling to reduce the incidence rate of MB (multibacillary) HD. By contrast, some areas of south India had earlier experienced good implementation of prolonged anti-microbial protection, with a consequent rapid decline in the incidence rate of new MB and LL HD (1). Whenever LL patients in endemic areas receive prolonged anti-microbial protection, reinfection is prevented and the incidence rate of MB HD declines rapidly.
Some great Brazilian colleagues have been pushing for highly bacillated patients to receive longer anti-microbial protection. As these voices of sanity and science gain traction, reinfection and transmission can be predicted to decline rapidly in Brazil (although contact with highly bacillated armadillos is unhelpful). For such good outcomes and impact to be achieved, Brazil and other endemic countries could usefully assert independence from ineffective or even harmful technical advice pushed by some elements in wealthy countries. Instead, success is more readily available by emulating highly impactful projects in other endemic areas. We could usefully encourage direct co-operation between endemic countries in order to accelerate success.
Twenty years after the powerful epidemiological impact of skin camps followed by mass multiple drug administration in hot spots was demonstrated (4), we have some elements in wealthy countries trying to drag us back to single drug use, that too for only household contacts. It would be good to keep moving forward towards success, not regressing towards drug resistance and stigmatising ineffective practices that depict even non-infectious patients as threats to contacts.
Brazil has led the world in rejecting use of a single drug for prophylaxis. This enlightened approach helps delay the selection of drug-resistant mutant bacilli, especially in those "de novo" LL patients who are mistaken for healthy contacts. LL patients require full multi-drug treatment and prolonged antimicrobial protection against reinfection, not a single dose of a single drug nor just a few doses of treatment.
Unprotected LL patients are overwhelmingly the dominant source of astronomical numbers of viable bacilli (6). Selecting drug resistant mutants in such patients shifts the frequency distribution of the entire bacillary population in an endemic area away from drug-susceptibility and towards drug-resistance. Brazil's enlightened rejection of single dose rifampicin helps to keep HD easily treatable. Brazil in this respect leads the world. There is no scientific reason for regressing from multiple drug use to any kind of single drug use in endemic areas.
It might be helpful to learn from the real world-leaders in reducing transmission, the projects in endemic areas that achieved well-documented rapid reduction in the incidence rate of MB HD. Their approach included
a) expert skin camps that allow stigma-free diagnosis of even hard-to-diagnose "de novo" LL HD,
b) prolonged anti-microbial protection for LL patients, reducing reinfection and stopping transmission at source.
Those two important elements were sufficient to yield up to 20%/year well-documented decline in the incidence rate of MB or LL HD (1-3). This was despite conspicuously low incomes in the concerned endemic areas at the relevant times.
For turbo-charging the decline of new MB HD in endemic hot spots we have the good example of FS Micronesia (4), that added a third element to the two above:
c) mass multi-drug administration at intervals.
This boosted the rate of decline in new cases to about 40%/year.
It is unprotected LL patients who uniquely shed astronomical numbers of viable bacilli, measured in tens of millions per day or even per nose blow (6). They shed bacilli both before and after MDT (in case of reinfection of LL patients with anergy as indicated by unresponsiveness to MIP vaccine). There is not much scientific basis for creating fear about the remaining patients. Even BL patients before or after treatment have been found to shed relatively small numbers of bacilli, if any (6).
For each HD patient with progressive disease there are vast numbers who are infected but who overcome the bacilli unaided. Increasing the frequency or sensitivity of case-finding uncovers many such cases who would otherwise go without detection, discrimination or deformity. (7) As more sensitive methods of diagnosis are introduced, it is important to educate the people of endemic areas about the spectrum of HD and the self-limiting, non-infectious character of the overwhelming majority of new infections. No HD patient need be regarded as infectious nor treated any less favourably than any other person unless a competent professional first certifies that they are shedding densely packed acid-fast bacilli in nose blows or in tissue fluid from ulcerated lesions.
What can each of us do to encourage success in Brazil? Could we support respect for the capability and potential of local professionals, allowing elbow room for them to succeed? Could we increase respect for patients instead of abandoning LL patients to the bacilli? Could we draw more attention to exemplary projects in endemic countries that achieved rapid decline in MB HD? Could we move increasingly towards fact-based epidemiology by spotlighting reinfection of LL patients?
Brazil with its ability to exercise independent scientific judgment is well placed to succeed. It is a world leader in the fight against HD, in some important respects. We could cheer on great Brazilian colleagues and wish them well as they pursue measurable epidemiological impact and foster deeper respect for persons affected.
Joel Almeida
References
1 Norman G, Bhushanam JDRS, Samuel P. Trends in leprosy over 50 years in Gudiyatham Taluk, Vellore, Tamil Nadu. Ind J Lepr 2006. 78(2): 167-185. reviewed and analysed further in: 1a. Almeida J. Karigiri, India: How transmission rapidly was reduced in a low-income population. LML 29 Oct 2020
2 Tonglet R, Pattyn SR, Nsansi BN et al. The reduction of the leprosy endemicity in north-eastern Zaire 1975/1989 J. Eur J Epidemiol. 1990 Dec;6(4):404-6 reviewed in: 2a. Almeida J. Reducing transmission in poor hyperendemic areas - evidence from Uele (DRC). LML 29 Nov 2019
3 Li HY, Weng XM, Li T et al. Long-Term Effect of Leprosy Control in Two Prefectures of China, 1955-1993. Int J Lepr Other Mycobact Dis. 1995 Jun;63(2):213-221. reviewed & analysed further in: 3a. Almeida J. What really happened in Shandong? LML 16 Nov 2019
4 WORKSHOP ON THE PREVENTION OF LEPROSY, POHNPEI, FEDERATED STATES OF MICRONESIA. 25-27 MAY 1999 sponsored by the Sasakawa Memorial Health Foundation Tokyo, Japan and the Western Pacific Regional Office of the World Health Organization. Int J Lepr, 67 (4) (SUPPLEMENT)
5 Gonçalves FG, Belone AFF, Rosa PS, Laporta GZ. Underlying mechanisms of leprosy recurrence in the Western Amazon . BMC Infectious Diseases (2019) 19:460
6. Davey TF, Rees RJ. The nasal discharge in leprosy: clinical and bacteriological aspects. Lepr Rev. 1974 Jun;45(2):121-34.
7. Jesudasan K, Bradley D, Smith PG, Christian M. The effect of intervals between surveys on the estimation of incidence rates of leprosy. Lepr Rev (1984) 55, 353-359
LML - S Deepak, B Naafs, S Noto and P Schreuder
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