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
Table 4 Estimated and true prevalences of tungiasis and severe tungiasis (>20 lesions)
Brazil Nigeria
1 2 3 4 5 6 7 8 9 10
Prevalence of tungiasis 37.8% 42.0% 21.1% 28.8% 18.8% 44.3% 15.0% 20.8% 44.1% 30.2%
on periungual sites
Prevalence of tungiasis
True prevalence 51.3% 52.1% 31.2% 33.6% 23.7% 54.4% 21.1% 28.9% 51.1% 40.5%
Estimated prevalence 47.3% 52.0% 28.7% 37.2% 26.0% 54.6% 21.8% 28.3% 54.4% 38.8%
(95% CI)
(43.0–51.5) (47.6–56.5) (24.8–32.6) (34.6–40.0) (23.5–28.6) (51.1–58.8) (21.8–24.4) (25.5–31.2) (46.9–61.6) (30.0–48.3)
Absolute error )4.0% )0.1% )2.5% 3.6% 2.3% 0.2% 0.7% )0.6% 3.3% )1.7%
Prevalence of severe
tungiasis (>20 lesions)
True prevalence 6.0% 6.5% 2.8% 2.2% 1.3% 4.7% 0.1% 0.8% 10.2% 5.2%
Estimated
5.7% 6.7% 1.7% 3.5% 1.1% 7.2% 0.2% 1.6% 7.2% 3.8%
prevalenceà (95% CI) (3.9–7.9) (4.7–9.2) (0.7–3.1) (2.5–4.7) (0.6–2.0) (5.5–9.1) (0.0–0.7) (0.9–2.6) (3.8–11.7) (0.9–8.6)
Absolute error )0.3% 0.2% )1.1% 1.3% )0.2% 2.5% 0.1% 0.8% )3.0% )1.4%
According to the equation y = 1.12 (x) + 5.0 where x is the prevalence determined to the rapid assessment method and y the estimated prevalence.
àAccording to the equation y = 0.24 (x) – 3.4 where x is the prevalence determined to the rapid assessment method and y the estimated prevalence.
examination. Thus, rapid diagnosis on the individual level
with calculation of accuracy markers, such as sensitivity, is
not needed in this case. On the other hand, reliable
estimation of the true prevalence of tungiasis and severity
of disease in a given community is useful. Our study shows
that the strength of association when applying the rapid
estimation was very high.
In communities of different size and with different point
prevalences, absolute errors of the estimated prevalences
were low and R 2 values were high. The reliability of the
proposed rapid assessment method did not vary considerably
between seasons or populations with distinct
socio-cultural characteristics. The wide diversity of
characteristics of the examined populations indicates that
this rapid assessment method may also be applicable in
other endemic regions in Latin America, the Caribbean or
sub-Saharan Africa. However, its external validity still has
to be determined for other settings with particular
ecological, epidemiological, geographical and sociocultural
characteristics.
We cannot rule out that inter-observer as well as intraobserver
bias may have influenced the results, as surveys
were conducted by different members of the research
group, and during a rather long period. We aimed to
reduce this source of bias by training all investigators
performing the clinical examinations in one study
site in Brazil, and by cross-checking quality of clinical
examinations.
Conclusion
Our rapid assessment method will be helpful in the
identification of communities at risk, as well as in planning
and monitoring control measures aimed at the reduction of
tungiasis in affected communities. The assessment can be
performed by community health workers and paramedical
personnel.
Acknowledgements
We thank the leaders and the people of the communities
involved. We also thank Fundação Mandacaru for supporting
the studies and Valéria Santos, Vania Santos (Brazil)
and ‘Nick’ (Nigeria) for skillful assistance. Travel grants
were made available by Deutscher Akademischer Austauschdienst
(DAAD ⁄ Germany) and by Coordenação de
Aperfeiçoamento de Pessoal de Nível Superior
(CAPES ⁄ Brazil), through the PROBRAL German-Brazilian
Academic Exchange Program, and by a PROÁFRICA grant
from the Conselho Nacional de Desenvolvimento Científico
e Tecnológico (CNPq ⁄ Brazil). L.A. received a PhD scholarship
from CAPES. J.H. is research fellow from CNPq.
862 ª 2010 Blackwell Publishing Ltd