Tungíase: doença negligenciada causando patologia grave

Tropical Medicine and International Health volume 15 no 7 pp 856–864 july 2010
L. Ariza et al. Rapid community assessment of tungiasis
prevalences from 21.1% (214 ⁄ 1015; survey 7 – Brazilian
rural community, rainy season) to 54.4% (462 ⁄ 849;
survey 6 – Brazilian urban slum, dry season). In general,
highest prevalences of tungiasis and of severe disease
were found in the dry season (surveys 1, 2, 6, 9, 10).
The highest prevalence (10.2%; 19 ⁄ 186) of severe
disease (>20 lesions) was found in one of the fishing
communities in Nigeria (survey 9). The maximal
number of lesions per individual ranged between 40 and
199 (Table 2).
In most surveys, men were more frequently infested
(prevalence 22.9%; 105 ⁄ 459–63.5%; 235 ⁄ 370) than
women (18.5%; 119 ⁄ 644–51.8%; 143 ⁄ 276) with a
male ⁄ female prevalence ratio between 1.7 and 1.0 (Table
2). However, the difference was only statistically significant
in the urban slum in Brazil (P < 0.0001).
Rapid assessment of prevalence in the communities
The six topographic areas considered as putative sites for
rapid assessment and their characteristics are summarized
in Table 3. Considering a high R 2 value, time and
simplicity of the procedure, we identified the periungual
areas of the toes as the most promising site. In fact, the
estimated prevalence based on this localization very
reliably predicted the overall true prevalence of tungiasis
(R 2 = 96%; P < 0.0001; Figure 3a).
After estimating the prevalence of tungiasis (expressed
as [estimated prevalence] = 1.12 · [prevalence on periungual
sites] + 5.0), absolute errors ranged between )4%
(survey 1) and +3.6% (survey 4; Table 4). The mean
absolute error was 1.9%.
Presence of embedded sand fleas at the periungual areas of
the feet also reliably estimated prevalence of severe disease
using the equation (R 2 = 76%; P = 0.001; Figure 3b).
Absolute errors of estimated prevalence of severe disease,
when compared to true prevalence of severe disease, ranged
between )3.1% (survey 9; Nigeria) and +2.5% (survey 6,
Brazil; Table 4). The mean absolute error was 0.9.
Discussion
Similar to other parasitic skin diseases, tungiasis is underestimated
and can be considered a Neglected Tropical
Table 3 Comparison of possible topographic areas used for rapid estimation of prevalence of tungiasis
Topographical area
Time needed
to examine one person Comments
Periungual areas of feet + Individual can be examined with minor disturbance;
sandals or thongs can be kept.
Diagnosis easily made by lay personnel
Right foot +++ Individual has to take off thongs and needs to stand
up to show heel and plantar side of foot. Areas
between and beneath toes are difficult to access, and
toes need to be spread.
Requires more skills of investigators, increased risk
of investigator bias.
Periungual areas of right foot + Individuals can be examined with minor disturbance
without taking off thongs ⁄ sandals.
Periungual area of any 1st toe + Individual can be examined with minor disturbance
without taking off thongs ⁄ sandals.
Increased risk for errors at data collection.
Periungual area of right 1st toe + Individual can be examined with minor disturbance
without taking off thongs ⁄ sandals.
Right 1st toe ++ Individual has to take off thong and needs to stand
up to show plantar side of toe. Area between toes I
and II is difficult to access, and toes need to be
spread. Increased disturbance.
Requires more skills of investigators, increased risk
of investigator bias.
Strength of
association (R 2 )
Relative values (+, ++, +++) are given, as the time to examine one person varies considerably within and between communities (according
to presence and number of lesions, age of individual, socio-cultural setting and experience of investigator).
860 ª 2010 Blackwell Publishing Ltd
96%
95%
93%
93%
88%
70%