Tungíase: doença negligenciada causando patologia grave

438 Feldmeier et al
lymph nodes were palpated for the presence of
swelling and pain (lymphadenitis).
To determine the severity of infestation, the body
was divided into two halves (right and left). Each half
was subdivided into 16 areas: interdigital spaces,
hand, wrist, arm, elbow, axilla, leg (excluding the
medial area of the thigh), foot, abdomen, ventral
thorax, mamillar/perimammilar area, back, buttocks,
genitals, inguinal area/medial area of the thigh, and
head (scalp/neck/face). Thus, the number of affected
areas possibly ranged from 0 to 32. Severe
scabies was arbitrarily defined as the presence of 12
or more infested topographic areas. 10
Illiteracy was defined as the inability to read and
write more than one’s own name.
Data storage and analysis
Data were entered twice into a database using a
software package (Epi Info, Version 6.04d, Centers
for Disease Control and Prevention, Atlanta, GA) and
checked for errors that may have occurred during
their entry. Then, data were transferred to another
software package (Stata, Version 9.0, Stata Corp,
College Station, TX) for analysis. Fisher exact test was
used to determine the significance of differences of
relative frequencies. For the identification of possible
risk factors, the odds ratios with the respective
95% confidence intervals were calculated.
Three individuals were given a diagnosis of scabies
during the first and the second survey. These
cases were entered into the risk factor analysis only
once. Control subjects were all individuals without
scabies during the first survey plus individuals who
had immigrated into the area after the first survey and
who were without scabies during the second survey.
In a second step multivariate logistic regression
using backward elimination was performed to calculate
adjusted odds ratios for the independent association
between exposure variables and the presence
of scabies. All variables on a significance level of P
less than .2 were included in the multivariate regression
model. Socioeconomic and behavioral variables
were based on households, except sharing of beds,
clothes, and towels, and use of shower and soap.
These exposure variables were entered in the model
on the individual level. Incidence (I ) was calculated
according to the formula I = P/D; where P is the
prevalence and D the average duration of disease. As
the mean duration of scabies in resource-poor settings
is estimated between 2 and 8 months, 2 the
incidence was calculated assuming 2, 6, and 8 months
of disease duration, respectively.
Ethical considerations
The study was approved by the ethical committee
of the Escola de Ciências Médicas de Alagoas, the
JAM ACAD DERMATOL
MARCH 2009
responsible ethical body in Alagoas State, Brazil.
Before the study, meetings were held in the community
with health care workers and community
leaders to explain the objectives. All participants
were informed about the study, and informed written
consent was obtained. In the case of minors, the
guardian was asked for written consent. If patients
were illiterate, the informed consent was read for
them and patients had to sign the informed consent
by their finger print. Any inhabitant of the study area
was free to refrain from participating without any
disadvantage for oneself or other family members.
If other skin diseases were diagnosed during the
examination, patients were referred to the primary
health care center of Feliz Deserto, where all treatment
is free of charge. At the end of the study, mass
treatment of all inhabitants of the village was
performed using ivermectin (2 3 200 g/kg body
weight) to relieve subjects from ectoparasites and
remaining intestinal helminths. Children younger
than 5 years were treated with mebendazole (2 3
100 mg).
RESULTS
In total, 2002 individuals were examined, 1014
during the first survey in the rainy season, and 988
during the second survey in the dry season. This
corresponded to 88.5% and 90.9% of the target
population, respectively. Men disproportionately
accounted for nonparticipants in both surveys.
Boys and young men (15-29 years) often worked
on surrounding farms during the week, where they
stayed from Monday to Friday, and therefore failed to
fulfill the admission criteria of spending 4 nights per
week in the study area.
Of the studied households, 89.3% had access to
electricity, and 81% had toilets on their compounds.
In all, 49.6% of the study members lived in brick-built
houses. Of the households, 83% had more than 4
members and 61.7% had a monthly income of less
than R$200 (the official minimum wage; approximately
US$105). The education level was low: 34.2%
of those aged 15 years or older were illiterate.
During the first door-to-door survey, 102 scabies
cases were detected (10.1%) and during the second,
94 (9.5%; P = .71). Three individuals were given a
diagnosis of scabies during the first and the second
survey, although these cases had been treated at the
end of the first survey. It remained unclear whether
this was a result of drug failure or a reinfestation.
Table I depicts age- and sex-specific prevalence
during the rainy and the dry seasons. The frequency
of scabies and severe scabies, and the proportion of
superinfected lesions (35.3% in the rainy vs 38.3% in
the dry season) were similar in both surveys.