1Department of Biological Science, University of State of Mato Grosso, Cáceres, Mato Grosso, Brazil.
2 Department of Parasitology, University of Campinas, Campinas, São Paulo, Brazil.
3 Department of Nursing, University of State of Mato Grosso, Cáceres, Mato Grosso, Brazil.
4 Department of Parasitology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil.
Corresponding author: Antonio Malheiros, Department of Biological Science, University of State of Mato Grosso, Cáceres 78200000, Mato Grosso, Brazil.
Telephone: +55 6532210500; Fax: +55 6532210500. E-mail: p151867@dac.unicamp.br and malheiros@unemat.br
Financial support
This work was supported by the Brazilian Ministry of Health – FUNASA, Foundation for Research of the State of Mato Grosso – FAPEMAT and the Brazilian
Research Council – CNPq for a postdoctoral fellowship to Antonio Francisco Malheiros.
403
Neotrop. Helminthol., 8(2), 2014
2014 Asociación Peruana de Helmintología e Invertebrados Afines (APHIA)
ISSN: 2218-6425 impreso / ISSN: 1995-1043 on line
ORIGINAL ARTICLE / ARTÍCULO ORIGINAL
INFECTION BY HOOKWORMS IN AN INDIGENOUS REMOTE REGION OF
THE LEGAL AMAZON, BRAZIL
INFECCION POR ANQUILOSTOMAS EN INDIGENAS DE UNA REGION REMOTA DE LA
AMAZONIA LEGAL, BRASIL
1,3* 2 3 4
Antonio Francisco Malheiros ; Patrick Mathews Delgado ; Larissa Scalon Lemos & Jeffrey Jon Shaw
Suggested citation: Malheiros, AF, Delgado, PM, Lemos, LS & Shaw, JJ. 2014. Infection by hookworms in indigenous of a
remote region from the legal amazon, brazil. Neotropical Helminthology, vol. 8, n°2, jul-dec, pp. 403-410.
Abstract
Keywords: Brasil - diagnosis - hookworms - infection - indigenous.
Hookworms infection has become an increasingly serious threat to public health in Brazilian
indigenous. Detection and/or clinical cases of hookworms have been reported in the past;
however, nothing is known about the prevalence among indigenous Tapirapé in Brazil. We studied
the presence of hookworms in indigenous Tapirapé ethnic group from county of Confresa, State of
Mato Grosso, Brazil. Stool samples were collected from 542 members of the Tapirapé ethnic
group and analyzed using formalin-ethyl ether and formalin-ethyl acetate sedimentation, and zinc
sulfate flotation. Hookworms were detected in 104 (19.24%) indigenous and the prevalence was
similar in males (21.29%) and females (17.20%). Males aged under 16 years were more
frequently infected. Symptoms such as diarrhea and abdominal pains were reported from 104
infected individuals . Other symptoms associated with hookworms infection were vomiting,
cramps and weight loss. No significant association with diarrhea was noted in individuals infected
with hookworms. Hookworms are frequent intestinal parasites in Tapirape indians and the results
suggest a high level of environmental contamination.
Resumen
Palabras clave: Anquilostomas – Brasil – diagnóstico – infección - indígenas.
La infección por anquilostomas se ha convertido en una amenaza cada vez más grave para la salud
pública en los indígenas de Brasil. La detección y casos clínicos de anquilostomas se han
informado en el pasado; sin embargo, no se sabe nada acerca de la ocurrencia entre los indígenas
Tapirapé en el Brasil. El objetivo de este estudio fue determinar la presencia de anquilostomas en
indígenas del grupo étnico Tapirapé, municipio de Confresa, Estado de Mato Grosso, Brasil. Las
muestras de heces fueron colectadas de 542 miembros de la etnia Tapirapé y analizadas por las
técnicas de sedimentación de formalina-éter y con formalina-acetato de etilo, y flotación de
sulfato de zinc, con el fin de obtener un diagnóstico de anquilostomas. Los anquilostomas se
detectaron en 104 (19,24 %) indígenas y la prevalencia fue similar en los hombres (21,29 %) y en
las mujeres (17,20 %). Los varones menores de 16 años se han asociado con positividad. Una parte
de los 104 individuos infectados, reportaron síntomas como diarrea y dolores abdominales. Otros
síntomas asociados con la infección por parásitos intestinales fueron vómitos, calambres y
pérdida de peso. No se encontró asociación significativa con la diarrea en los individuos
infectados. Los anquilostomas son parásitos intestinales frecuentes en los indios Tapirapé y los
resultados sugieren una contaminación elevada del ambiente en el que viven estos indígenas.
INTRODUCTION et al., 2005; Bóia et al., 2009). Within the
epidemiological profile of these processes,
strong presence of parasitic diseases has
historically been denoted (Santos et al., 1995;
Bóia et al., 2009; Palhano-Silva et al., 2009).
The aim of this study was to determine the
presence of hookworms in 542 indigenous
Tapirapé ethnic group from Confresa, State of
Mato Grosso (western Brazil), the region with
the highest number of indigenous groups in
Brazil.
Study site and Population
The study was carried out in the Tapirapé
community, situated 30 km from the Confresa
municipality, State of Mato Grosso, Brazil. The
indigenous reserve is located in Legal Amazonia
and inhabited by 542 members of the Tapirapé
ethnic group. The members of this tribe have
many free roaming animals including dogs, cats,
chickens, and pigs. The principal source of
protein for this population is derived from
fishing and hunting animals such as the paca
(Cuniculus paca (Linnaeus, 1766)), agouti
(Dasyprocta punctata Gray, 1842), anteater
(Tamandua tetradactyla (Linnaeus, 1758)),
Soil-transmitted helminths are a major global
cause of morbidity and malnutrition. The World
Health Organization (WHO) estimates that
approximately 740 million of the world's
population is affected by hookworms, resulting
in 65.000 deaths annually, which are closely
correlated to poverty, poor environmental
hygiene and impoverished health services. Two
species of hookworms commonly infect
humans, Ancylostoma duodenale (Dubini, 1843)
and Necator americanus (Stiles, 1902). A.
duodenale predominates in the Middle East,
North Africa and India, while N. americanus
predominates in the Americas, Sub-Saharan
Africa, Southeast Asia, China, and Indonesia
(Georgiev, 2000; Neves et al., 2005).
Several studies of the health conditions among
indigenous groups in Brazil have proven that the
issue represents a growing challenge. The
processes of colonization and expansion of the
economic frontiers has been accompanied by
significant deterioration of the health conditions
of the indigenous people, thereby leading to
degrees of depopulation (Riveiro, 1956; Neves
Malheiros et al.
Hookworms in indigenous from Brazil
MATERIALS AND METHODS
404
Neotrop. Helminthol., 8(2), 2014
tortoise (Chelonoidis denticulata (
1766)), capuchin monkey (Cebus capucinus
(Linnaeus, 1758)), deer (Mazama americana
(Erxleben, 1777)), armadillo (Priodontes
maximus (Kerr, 1792)), tapir (Tapirus terrestris
(Linnaeus, 1758)), mallard (Anas platyrhynchos
Linnaeus, 1758), and curassow (Crax globulosa
Spix, 1825). Piped water is drawn from nearby
rivers and is delivered to every household, but it
is neither filtered nor chlorinated. There is a
general lack of adequate sanitation; only one
public latrine is available for the entire village;
however, this latrine is not used by all the
villagers. The Tapirapé indigenous population
lives in houses at ground level (Fig. 1). The
people of this village speak their own native
language and Portugues. Their children do not
attend schools and do not wear shoes.
A total of 542 stool samples (279 from females
and 263 from males) were collected during
January 2009 to July 2011. These collection
times thus occurred in each of the two main
climatic seasons in the Amazon region (dry and
raining season).
Laboratory Analyses
The fecal concentrates were obtained by
techniques of formalin-ethyl ether and formalin-
ethyl acetate sedimentation, and zinc sulfate
flotation (Truant et al., 1981; Malheiros et al.,
2011; Malheiros et al., 2014) and were examined
by light microscopy (x400). The consistency
(form, softness, loose, and watery) of all fecal
samples was noted on collection. Demographic
data and clinical information were recorded for
all members of the tribe. At the end of each
collection, the indigenous received medication
by health workers (Mebendazole oral doses of
100 mg every 12 h during 3 days).
Statistical Analyses
The association of presence of hookworms eggs
with age (young or adult), gender (male or
female) and diarrhea was analyzed using
Pearson's chi-square test and Fisher's exact tests.
Differences were considered statistically
significant when p?0.05. Statistical analyses
were performed using SPSS 15.0 (Statistical
Package for Social Science (SPSS) Inc.).
Linnaeus, Ethical considerations
The research was approved by the Ethics
Committee of the Institute of Biomedical
Sciences of the University of São Paulo, and
consent was obtained from all human adult
participants and from parents or legal guardians
of minors, according to National Committee for
Ethics in Research (CONEP-120/2008).
In the present study, 542 individuals from six
indigenous villages were enrolled of whom 104
(19.24%) were positive for hookworms based on
microscopy of fecal concentrates (Table 1, Fig.
2).
The relationship between gender of the host and
hookworms infection was calculated and the
prevalence was similar in males (21.29%,
56/263) and in females (17.20%, 48/279)
(p=0.56) (table 1). Infection was more common
in children (61.44%) than in adults (2.57%) and
was often found within family. Males being
under 16 years of age were associated with
positivity for hookworms (p ? 0.001) (Table 1).
For a total of 104 individuals infected with
hookworms, symptoms such as diarrhea and
abdominal pains were reported. No significant
association with diarrhea was noted in
individuals infected with hookworms (p= 0.42).
The mayority of hookworms infected
indigenous were mono-infected (85.58%
89/104). Co-infection with other helminths was
14.42% (15/104) and included: Ascaris
lumbricoides (n=8), Trichuris trichiura (n=6)
and Taenia sp. (n=1).
From the collected samples, it was noticeable
that hookworms were more prevalent in the dry
season (67.31%), than in the raining season
(32.69%). Seventy-one children (79.79%)
acquired infection of hookworms at least once
during the dry season; while in the raining
season 19 were infected (20.21%). Hookworm
was detected during each sampling throughout
the study period.
RESULTS
405
Malheiros et al.
Hookworms in indigenous from Brazil
Figure 1. Raised dwelling of indigenous Tapirapé, Brazil.
Figure 2. Egg of hookworm examined in fecal concentrates observed by light microscopy (x400) (Scale bar spans 10µm).
406
Neotrop. Helminthol., 8(2), 2014
Understanding the epidemiology of hookworms
infection in isolated indigenous communities is
important in designing effective strategies to
combat this neglected tropical disease. This
study reports, for the first time, the presence of
hookworms in members of the Tapirapé ethnic
group. The diagnosis by microscopic
examination used here is traditionally used for
the diagnosis of parasitic infections. In the same
manner, multiple sampling, as well as species-
specific concentration and staining methods are
all employed to enhance the sensitivity and
specificity of the detection of different parasite
species (Supali et al., 2010). Although,
difficulties in differentiating to the species level
using microscopy can result in an inaccurate
picture of a disease, such as the differentiation
between the hookworm species. Given this
context, multiplex real-time PCR assay is highly
recommended for the simultaneous detection
and quantification of A. duodenale and N.
americanus DNA in feacal samples (Haque et
al., 1998; Verweij et al., 2007; Supali et al.,
2010). This assay proved to be specific (100%)
and sensitive (100%), for the detection of A.
duodenale and N. americanus respectively.
However, this tecnique has some
disadventagens; it is technically complex, time
consuming, and expensive (Haque et al., 1998).
The resulting prevalence in our study, was
similar to other studies in Brazilian indigenous
groups (Santos et al., 1995; Miranda et al., 1999;
Bóia et al., 2009; Palhano-Silva et al., 2009) and
similar to studies in other developing countries
(French Guiana and Panamá ) (Carne et al.,
2002; Halpenny et al., 2013). The fact of the
similarity in prevalence could be related to a
number of factors such as poor hygiene,
inadequate sanitation, water intake that was
neither filtered nor chlorinated, lack of shoes,
low education, low socioeconomic status which
are prevalent in communities indigenous and in
rural zones isolated (Bethony et al., 2006;
Steinman et al., 2006; Ziegelbauer et al., 2012;
Briones et al., 2013; Souza et al., 2013). Another
important factor which affects the prevalence of
hookworms is the habit of defecating in and
around the habitation. The indigenous Tapirapé
tends to live in houses at ground level and during
the raining season eggs and larvas of helminths
can be carried by rainwater into houses
(Wongstitwilairoong et al., 2007; Briones et al.,
2013). The eggs may remain in the houses for
several days or months, reaching infective
stages, thus children and adults indigenous can
be constantly infected. According Briones et al.
(2013) difference in housing design may
contribute to the infection by helminths.
Furthermore, The indigenous population that
lives in houses on stilts would be less prone to
infections by helminths when compared that live
in houses at ground level (Briones et al., 2013).
In our study, the absence of statistical difference
of infection between males and females is
similar to other studies in Brazilian indigenous
(Santos et al., 1995; Miranda et al., 1999; Bóia et
al., 2009; Palhano-Silva et al., 2009). This fact is
related to both gender are exposed to the same
DISCUSSION
Table 1. Prevalence of hookworms in members of the indigenous Tapirapé ethnic group from the Brazilian Amazon.
Variable Individuals examined hookworms
Positive % p value
Gender
Females 279 48 17.20 NS
Males 263 56 21.29
Age (years)
3-16 153 94 61.44 ?0.001a
?17 389 10 2.57
Total 542 104 19.24
NS: not significant.ap ? 0.001.
407
Malheiros et al.
Hookworms in indigenous from Brazil
impoverished conditions. However, we found
that the Infection was more common in children
than in adults. It is known that children are more
susceptible to infection by parasites as compared
to young and elderly humans. Indeed, studies in
indigenous populations have highlighted a
factor possibly involved in greater transmission
of hookworms in children, that is the absence of
the use of footwear for most of them allowing
greater contact with soil containing infective
forms (Carne et al., 2002; Briones et al., 2013).
Likewise, environmental factors must be
considered. Indeed, hookworms are
predominantly transmitted in tropical and
subtropical regions of the world. The climate in
the region is tropical humid with average annual
temperature of 28.6°C, high humidity of 85%,
and sandy soil of the region favor the
development and maintenance of infective
stages of these parasites. In the present study, the
largest number of hookworms cases were
observed bethween the months that
corresponding the end of the rainy season
(April) and early dry season (May to July).
However, hookworm was detected during each
sampling throughout the study period which is in
accordance with previous studies that reported
presence of hookworms and others intestinal
parasites throughout all seasons (Siwila et al.,
2011; Malheiros et al., 2011; Malheiros et al.,
2014).
Hookworm infection is generally considered to
be asymptomatic, silent and insidious
(Georgiev, 2000; Neves et al., 2005). There are
general some symptoms that an individual may
experience soon after infection. Indeed, a high
worm burden can lead to marked eosinophilia. In
the present study, some symptoms such as
diarrhea and abdominal pains were observed,
however, not was measured the eosinophilia in
the indigenous infected with hookworms,
however, eosinophil count in the peripheral
blood is highly recommended. Our study
measured the presence or absence of
hookworms infection in individuals. There was
no attempt to quantify the burden of infection in
individuals or assess individual propensity to
infection. These issues will be addressed once
Bethony, J, Brooker, S, Albonico, M, Geiger,
SM, Loukas, A, Diemert, D & Hotez, PJ.
2006.
Bóia, MN, Carvalho-Costa, FA, Campos, FS,
Porras-Pedroza, BE, Faria, EC,
Magalhães, GAP & Da Silva, IM. 2009.
Briones, CC, Torres, HZ, Canales, M, Stamato,
CM, O'Riordan, TG & Terashima & A.
2013.
Carne, B, Motard, A, Bau, P, Day, C, Aznar, C &
Soil-transmitted helminth
infections: ascariasis, trichuriasis, and
hookworm. The Lancet, vol. 367, pp.
1521–1532.
Tuberculosis and intestinal parasitism
among indigenous people in the Brazilian
Amazon. Revista de Saúde Pública, vol.
43, pp. 1-3.
Differences in prevalence of
geohelminth infections between
indigenous and settler populations in a
remote Amazonian region of Peru.
Tropical Medicine & International
Health, vol. 18, pp. 615–618.
ACKNOWLEDGMENTS
BIBLIOGRAPHIC REFERENCES
deworming and follow-up monitoring programs
be established in the ethnic group Tapirapé.
We found that the indigenous communities have
a moderate prevalence of hookworms and is a
frequent intestinal parasite in members of the
indigenous Tapirapé. The transmission of the
parasites is related with impoverished living
conditions. Likewise, a lack of fecal hygiene and
the habit of walking barefoot are widespread in
the unchanging Amazonian environment and
contribute to this phenomenon.
The authors thank the Brazilian Ministry of
Health, Foundation for Research of the State of
Mato Grosso-FAPEMAT and the Brazilian
Research Council-CNPq for research funding.
The authors thank Dr. Omar Mertins for
reviewing this manuscript.
408
Neotrop. Helminthol., 8(2), 2014
Moreu, B. 2002.
Georgiev, VS. 2000.
Halpenny, CM, Paller, C, Koski, KG, Valde´s,
VE & Scott, ME. 2013.
Haque, R, Ali, IK, Akther, S & Petri, Jr WA.
1998.
Malheiros, AF, Stensvold, RC, Graham, CC,
Braga, GB & Shaw, JJ. 2011.
Malheiros, AF, Mathews, PD, Scalon, LL,
Braga, GB & Shaw, J.J. 2014.
Miranda, RA, Xavier, FB, Nascimento, JRL &
Menezes, RC. 1999.
Neves, DP, Mello, AL, Vitor, RWA & Linardi,
PM. 2005.
Palhano-Silva, CS, Araújo, JG, Lourenço, AEP,
Bastos, OMP, Santos, RV & Coimbra,
CEA. 2009.
Ribeiro, D. 1956.
Intestinal parasitoses
among Wayampi Indians from French
Guiana. Parasite, vol. 9, pp.167-174.
Necatoriasis: treatment
and developmental therapeutics. Expert
Opinion on Investigational Drugs, vol. 9,
pp.1065–1078.
Regional,
household and individual factors that
influence soil transmitted helminth
reinfection dynamics in preschool
children from rural indigenous Panamá.
PLoS Neglected Tropical Diseases, vol. 7,
e2070, pp. 1-11.
Comparison of PCR, Isoenzyme
analysis, and antigen detection for
diagnosis of Entamoeba histolytica
infection. Journal of Clinical
Microbiology, vol. 36, pp. 449-452.
Molecular
characterization of Blastocystis obtained
from members of the Indigenous Tapirapé
ethnic group from the Brazilian Amazon
region, Brazil. The American Journal of
Tropical Medicine and Hygiene, vol. 85,
pp.1050-1053.
Prevalence
of Hymenolepis nana in indigenous
Tapirapé ethnic group from the Brazilian
Amazon. American Journal of Biomedical
Research, vol. 2, pp.16-18.
Prevalence of
intestinal parasitism in Tembé tribe indian
settlements, Brazilian Eastern Amazon.
Revista da Sociedade Brasileira de
Medicina Tropical, vol. 32, pp. 389-393.
Parasitologia Humana. pp.
nd
264 2 ed. São Paulo: Ed. Atheneu.
Intestinal parasitic infection
in the Suruí Indians, Brazilian Amazon.
Interciencia, vol. 34, pp. 259-264.
Conviviality and
contamination. Dissociative effects of
population due to epidemics in indigenous
groups. Sociologia, vol. 18, pp. 3-50.
Intestinal parasitism in the
Xavánte Indians, central Brazil. Revista
do Instituto de Medicina Tropical São
Paulo, vol. 37, pp.15-18.
Seasonal prevalence and
incidence of Cryptosporidium spp. and
Giardia duodenalis and associated
diarrhoea in children attending pre-
school in Kafue, Zambia. Transactions of
the Royal Society of Tropical Medicine
and Hygiene, vol. 105, pp.102-108.
Human infection by Trichostrongylus spp.
in residents of urban areas of Salvador
city, Bahia, Brazil. Biomédica, vol. 33, pp.
439-445.
Schistosomiasis and
water resources development: systematic
review, meta-analysis, and estimates of
people at risk. The Lancet Infectious
Diseases, vol.6, pp. 411–425.
Polyparasitism
and its impact on the immune system.
International Journal for Parasitology,
vol. 40, pp. 1171–1176.
Comparison of formalin-ethyl ether
sedimentation, formalin-ethyl acetate
sedimentation and zinc sulfate flotation
techniques for detection of intestinal
parasites. Journal of Clinical
Microbiology, vol. 13, pp. 882-884.
S i m u l t a n e o u s d e t e c t i o n a n d
quantification of Ancylostoma
duodenale, Necator americanus, and
Oesophagostomum bifurcum in fecal
samples using multiplex real-time PCR.
The American Journal of Tropical
Santos, RV, Coimbra, CE, Flowers, NM & Silva,
JP. 1995.
Siwila, J, Phiri, IGK, Enemark, HL, Nchito, M &
Olsen, A. 2011.
Souza, RP, Souza, JN, Menezes, JF, Alcântara,
LM, Soares, NM & Aquino, TC. 2013.
Steinmann, P, Keiser, J, Bos, R, Tanner, M &
Utzinger, J. 2006.
Supali, T, Verweij, JJ, Aprilianto, EW, Djuardi,
Y, Hamid, F, Kaisar, MMM, Wammes, LJ,
Lieshout, LV, Luty, AJF, Sartono, E &
Yazdanbakhsh M. 2010.
Truant, AL, Elliott, SH, Kelly, MT & Smith, JH.
1981.
Verweij, JJ, Brienen, EA, Ziem, J, Yelifari, L,
Polderman, AM & Lieshout, VL. 2007.
409
Ziegelbauer, K, Speich, B, Mäusezahl, D, Bos,
R, Keiser, J & Utzinger, J. 2012. Effect of
sanitation on soil-transmitted helminth
infection: systematic review and meta-
analysis. PLoS Medicine, vol.9, pp.
e1001162.
Malheiros et al.
Hookworms in indigenous from Brazil
Medicine and Hygiene, vol. 77, pp.
685–690.
Intestinal parasitic infections
among pre-school children in
Sangkhlaburi, Thailand. The American
Journal Tropical Medicine and Hygiene,
vol. 76, pp. 345–350.
Wongstitwilairoong, B, Srijan, A,
Serichantalergs, O, Fukuda, CD,
McDaniael, P, Bodhidatta, L & Mason,
CJ. 2007.
Received September 22, 2014.
Accepted November 30, 2014.
410
