Tungíase: doença negligenciada causando patologia grave

Published by Maney Publishing (c) Liverpool School of Tropical Medicine
58 HEUKELBACH ET AL.
DISCUSSION
Although generally neglected by the publichealth
sector and the scientific community,
HrCLM can be a common condition in
warm-climate countries, especially in
resource-poor communities. There are few
basic epidemiological data available and
control in the endemic areas has rarely been
attempted (McCrindle et al., 1996). Thus,
HrCLM can be considered another
neglected disease of neglected populations
(Molyneux et al., 2005; Harms and
Feldmeier, 2007).
The present results indicate that, in a
typical rural village in Brazil, HrCLM is a
common parasitic skin disease in small
children and male adolescents. While the
infants and small children appear to be at
constant high risk of acquiring HrCLM,
boys aged 15–19 years are predominantly
affected in the rainy season. The latter
observation may be explained by genderrelated
behaviour patterns that are accentuated
in the rainy season. Adolescent girls
generally stay at home during the day,
performing domestic chores, chatting with
friends, styling their hair, or grooming
younger siblings, whereas their male counterparts,
whatever the season, tend to linger
in the streets or play soccer barefoot in
public squares, where dogs and cats stroll
around.
The age-, gender- and season-specific
trends seen in the prevalence of HrCLM
in Feliz Deserto are useful indicators of
where and when the larvae that cause the
disease are acquired. In rural Brazil, infants
and toddlers are allowed to crawl or sit on
the ground inside the house or in the
surrounding compound, whatever the season,
sometimes without wearing nappies or
underwear. Given these habits, the observation
that, in children aged ,5 years,
prevalence was high (and 3.7-fold higher in
the rainy season than in the dry season)
indicates that most transmission to humans
of the larvae causing HrCLM probably
occurs in domestic or, particularly, peridomestic
areas.
In the rainy season, animal faeces will be
dispersed with each precipitation, thereby
increasing the area of contamination, and
the parasites that cause HrCLM are more
likely to develop successfully into the mammal-infective
third-stage larvae, and also
survive longer, in damp soil than in dry soil
(Heukelbach et al., 2003). This is why, in
another endemic area of Brazil, precipitation
and the incidence of HrCLM were
found to be closely related (Heukelbach
et al., 2003). Interestingly, those living in
endemic areas are often aware that HrCLM
is associated with rainfall (Dafalla et al.,
1977; Heukelbach et al., 2003).
Although tourists to endemic areas rarely
visit resource-poor communities, they may
often walk barefoot, across soil that may well
be contaminated with the larvae that can
cause HrCLM, on their way to and from
beaches and on the beaches themselves. In
France, Ansart et al. (2007) recently found
tourists to be at significantly greater risk of
HrCLM than migrants, expatriates or business
travellers. In a group of Canadian
tourists who had visited Barbados, walking
TABLE 3. The results of a logistic regression analysis for factors associated with hookworm-related cutaneous larva
migrans
Factor Adjusted odds ratio and (95% confidence interval) P
Age (years) 0.96 (0.94–0.98) ,0.001
Monthly family income ,R$200 *
1.50 (0.97–2.33) 0.07
Sand or clay floor inside house 1.99 (1.22–3.23) 0.005
Always walks barefoot 1.77 (1.12–2.80) 0.014
* At the time of this study 2.40 Brazilian Reais (R$) were the equivalent of U.S.$1.00.