-from Epidemiological Bulletin, Vol. 23 No. 3, September 2002-
Rationale for surveillance
Cutaneous leishmaniasis is endemic in over 70 countries. The yearly incidence
is estimated at 1 500 000 cases. The disease has several clinical forms: localised
cutaneous leishmaniasis, diffuse cutaneous leishmaniasis, the most difficult
to treat, and (in the western hemisphere mainly) mucocutaneous leishmaniasis,
which is the most severe form as it produces disfiguring lesions and mutilations
of the face. In foci where man is believed to be the sole reservoir (anthroponotic
foci), epidemics are linked to human migrations from rural to poor suburban
areas; in zoonotic foci, where mammals are the reservoirs, epidemics are related
to environmental changes and movement of non-immune people to rural areas. Surveillance
is essential to establish disease impact and to monitor efforts towards the
control of disease and the detection of epidemics.
Recommended case definition
Clinical description
Appearance of one or more lesions, typically on uncovered parts of the body.
The face, neck, arms and legs are the most common sites. At the site of inoculation
a nodule appears, and may enlarge to become an indolent ulcer. The sore remains
in this stage for a variable time before healing, and typically leaves a depressed
scar. Other atypical forms may occur. In some individuals, certain strains can
disseminate and cause mucosal lesions. These sequelae involve nasopharyngeal
tissues and can be very disfiguring.
Laboratory criteria for diagnosis
– positive parasitology (stained smear or culture from the lesion)
– mucocutaneous leishmaniasis only: positive serology (IFA, ELISA).
Case classification
WHO operational definition:
A case of cutaneous leishmaniasis is a person showing clinical signs (skin
or mucosal lesions) with parasitological confirmation of the diagnosis (positive
smear or culture) and/or, for mucocutaneous leishmaniasis only, serological
diagnosis.
Recommended types of surveillance
At peripheral level individual patient records must be retained for investigation
and case management.
Routine monthly reporting of aggregated data of cases from periphery to intermediate and central level.
Active case finding through surveys of selected groups or mass surveys (standardised and periodical) is an alternative to estimate the prevalence of cutaneous leishmaniasis.
International: annual reporting from central level to WHO (limited number of countries).
Recommended minimum data elements
Individual patient records at peripheral level:
Leishmaniasis data: clinical features, date of diagnosis, parasitological
(Mucocutaneous leishmaniasis only) and serological diagnosis, Leishmania species,
treatment outcome.
Identification data: unique identifier, age, sex, geographical information, past travels, duration of stay at current residence.
Aggregated data for reporting:
Number of cases by age, sex, type of diagnosis.
Recommended data analysis, presentation, reports
Tables:
Incidence by geographical area, by age, by sex, by type of diagnosis, by month
/ year.
Point prevalence (if active case detection).
Maps: Incidence by village.
Principal uses of data for decision-making
– Evaluate the real extent of the problem and the main populations at risk
– Improve and focus the control activities
– Improve management and follow-up of cutaneous leishmaniasis, disseminated
cutaneous leishmaniasias and mucocutaneous leishmaniasis patients (WHO guidelines)
– Identify technical and operational difficulties
– Evaluate impact of control interventions
– Anticipate epidemics
Special aspects
The prevalence of cutaneous leishmaniasis tends to be grossly underestimated
because most of the official data are obtained through passive case detection
only. Other factors that may lead to misdiagnosis or non-diagnosis are: wide
scatter of foci, limited access to medical facilities, scarcity of diagnostic
facilities and limited or irregular availability of first-line drugs.
Source: "WHO Recommended Surveillance Standards, Second edition,
October 1999”, WHO/CDS/CSR/ISR/99.2
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Epidemiological Bulletin, Vol. 23 No. 3, September
2002