Innovative and intensified disease management (IDM) includes a range of different
interventions - ranging from medicine to surgery - to relieve the symptoms and
consequences of a group of neglected tropical diseases (NTDs) for which effective tools
are scarce or where the widespread use of existing tools is limited. The World Health
Organisation (WHO) has developed a series of strategies to achieve the control,
elimination and eventual eradication of these NTDs, comprising universal access to early
diagnosis and prompt treatment, improving active surveillance, integrating passive
surveillance into health-service provision, and accelerating efforts towards elimination
and eradication by intensifying core interventions. Appropriate targeting of IDM
interventions requires accurate epidemiological data on the distribution of these NTDs
within endemic countries. In most instances however, existing case register data
generated through national health management information systems or during programmatic
activities do not provide an accurate representation of the true burden of IDM NTDs.
A number of IDM NTDs are characterised by cutaneous manifestations that are associated
with long-term disfigurement and disability. These include Buruli ulcer, cutaneous
leishmaniasis, leprosy, mycetoma, yaws, onchocerciasis and lymphoedema and hydrocele
(resulting from lymphatic filariasis and podoconiosis). These diseases require similar
case-detection approaches, presenting opportunities for the development of novel,
integrated mapping approaches. Population-based prevalence surveys (PBPS) are the gold
standard methodology for obtaining accurate disease estimates when case detection and
reporting through the health system is incomplete, and these have been used to provide
sub-national estimates of disease distributions for yaws and podoconiosis. For less
common outcomes (fewer than 1 case in 1000 individuals) however, standard PBPS rapidly
become unfeasible. Given that the expected prevalence range for many of these IDM NTDs in
endemic regions lies between as low as 1 in 10,000 for Buruli ulcer and 1-5% for yaws, it
is clear that the PBPS approach requires adaptation to achieve the samples sizes needed
to generate sufficiently precise prevalence estimates.
One alternative to randomly sampling individuals or households is to screen all residents
within sampling clusters. House-to-house screening by mobile expert teams would likely
yield the highest number of cases, but such a strategy would be expensive and difficult
to sustain. As an alternative, trained village volunteers have been used during
programmatic activities to effectively detect and refer diseases such as Buruli ulcer and
leprosy in a number of countries. Given how difficult it is to diagnose many IDM-NTDs
accurately, using community volunteers to perform an exhaustive house-to-house case
search would require follow up expert case validation. The success of such an approach
would thus rely on high levels of community awareness, coupled with well-trained village
volunteers being able to recognise possible conditions, and a highly skilled, mobile
case-validation team to confirm all potential cases. Effectively incorporating skill
development in IDM-NTD screening among village volunteers could however represent a
long-term and sustainable solution to the complex issue of managing these conditions at
the community and primary health care level.
This study aims to establish the prevalence and distribution of case-management NTDs in
the county of Maryland, Liberia using an integrated two-stage cluster-randomised sampling
approach, including assessment of the proportion of cases not currently known to the
health system.
The specific objectives include:
To generate regional prevalence estimates of (i) lymphatic filariasis-associated
lymphoedema and hydrocele, (ii) yaws, (iii) Buruli ulcer and (iv) leprosy in
Maryland, Liberia, including the proportion of cases not currently known to the
health system
To model the endemicity status of (i) lymphoedema and hydrocele, (ii) yaws, (iii)
Buruli ulcer and (iv) leprosy to support the development of targeted, integrated
control strategies.
To compare case detection rates from active community-based screening and validation
with passive case detection reported through routine health system reports and
health management information systems.
This protocol represents a novel tool for integrated mapping of IDM-NTDs. These
conditions are difficult to diagnose and lack effective tools for both case finding and
disease management purposes. This strategy may provide a template for cost-effective case
identification and management that can be integrated within routine health systems in
similar epidemiological settings.