1,721,030 research outputs found
Certifying the interruption of Chagas disease transmission by native vectors: cui bono?
Get PDFCertifying the absence of Chagas disease transmission by native vectors lacks scientific grounds and weakens long-term control-surveillance systems to the detriment of people living under risk conditions. Instead, a regular “certification of good practice” (including vector control-surveillance, case detection/patient care and blood safety) could help achieve sustained disease control.Fil: Abad-Franch, Fernando. Instituto Leônidas e Maria Deane-Fiocruz; Brasil;Fil: Diotaiuti, Liléia. Centro de Pesquisas René Rachou-Fiocruz; Brasil;Fil: Gurgel-Gonçalvez, Rodrigo. Universidade de Brasília; Brasil;Fil: Gurtler, Ricardo Esteban. Consejo Nacional de Invest. Científ.y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Bs. As; Argentina
Modeling disease vector occurrence when detection is imperfect: infestation of Amazonian Palm Trees by Triatomine bugs at three spatial scales
No full textFailure to detect a disease agent or vector where it actually occurs constitutes a serious drawback in epidemiology. In the pervasive situation where no sampling technique is perfect, the explicit analytical treatment of detection failure becomes a key step in the estimation of epidemiological parameters. We illustrate this approach with a study of Attalea palm tree infestation by Rhodnius spp. (Triatominae), the most important vectors of Chagas disease (CD) in northern South America. The probability of detecting triatomines in infested palms is estimated by repeatedly sampling each palm. This knowledge is used to derive an unbiased estimate of the biologically relevant probability of palm infestation. We combine maximum-likelihood analysis and information-theoretic model selection to test the relationships between environmental covariates and infestation of 298 Amazonian palm trees over three spatial scales: region within Amazonia, landscape, and individual palm. Palm infestation estimates are high (40–60%) across regions, and well above the observed infestation rate (24%). Detection probability is higher (,0.55 on average) in the richest-soil region than elsewhere (,0.08). Infestation estimates are similar in forest and rural areas, but lower in urban landscapes. Finally, individual palm covariates (accumulated organic matter and stem height) explain most of infestation rate variation. Individual palm attributes appear as key drivers of infestation, suggesting that CD surveillance must incorporate local-scale knowledge and that peridomestic palm tree management might help lower transmission risk. Vector populations are probably denser in rich-soil sub-regions, where CD prevalence tends to be higher; this suggests a target for research on broad-scale risk mapping. Landscape-scale effects indicate that palm triatomine populations can endure deforestation in rural areas, but become rarer in heavily disturbed urban settings. Our methodological approach has wide application in infectious disease research; by improving eco-epidemiological parameter estimation, it can also significantly strengthen vector surveillance-control strategies
Interação espacial entre Triatoma brasiliensis Neiva, 1911 e Triatoma pseudomaculata Corrêa e Espínola, 1964 em ecótopos artificiais no município de Jaguaretama - CE, Brasil
No full textTriatoma brasiliensis e Triatoma pseudomaculata são vetores do Trypanosoma cruzi, agente da doença de Chagas, na Caatinga do nordeste do Brasil. Na natureza, essas espécies ocupam diferentes ecótopos e exploram diferentes hospedeiros. T. brasiliensis é terrestre e está associado a afloramentos rochosos (e cactos em algumas áreas) frequentemente compartilhados por roedores, enquanto T. pseudomaculata é arbóreo e parece alimentar-se principalmente de aves. Ambas as espécies, no entanto, podem infestar habitats feitos pelo homem, onde a possibilidade surge para a competição sobre os principais recursos - abrigo e sangue. Determinamos a ocorrência / coocorrência de T. brasiliensis e T. pseudomaculata em 412 ecótopos artificiais (91 habitações) para investigar padrões de segregação de espécies e investigar dois candidatos a processos subjacentes: (a) partição de recursos (T. brasiliensis preferindo ecótopos minerais ou ocupados por roedores e T. pseudomaculata preferindo ecótopos ocupados por vegetação ou aves) e (b) competição interespecífica verdadeira (cada espécie efetivamente evitando a outra). Usamos modelos lineares mistos generalizados (GLMMs) para identificar correlatos de ocorrência específica, incluindo a coocorrência de outras espécies. Ambas as espécies co-ocorreram em quatro ecótopos (0,97%). T. brasiliensis (12,9% de ocorrência geral) foi mais comum que T. pseudomaculata em ecótopos minerais (17,9% vs. 3,46%) e em ecótopos utilizados por roedores (74,1% vs. 11,1%); o melhor desempenho do T. brasiliensis GLMM estimou um forte efeito positivo da disponibilidade de roedores na ocorrência desses insetos (\03B2roedor = 3,55 ± 0,57EP) Em contraste, T. pseudomaculata foi mais rara (7,1%) e ocorreu mais frequentemente que T. brasiliensis em ecótopos vegetais (13,6% vs. 6,8%) e em ecótopos utilizados por aves (19,3% vs 6,4%); o melhor desempenho de T. pseudomaculata GLMM estimou o efeito da presença de aves na ocorrência de insetos como \03B2aves = 2,30 ± 0,48EP. Os GLMMs não revelaram nenhuma evidência de que a ocorrência de uma espécie afetou a probabilidade de que o outro co-ocorresse no mesmo ecótopo, após o ajuste para as características do ecótopo e a disponibilidade do hospedeiro. Esses achados sugerem que as espécies de estudo mantêm a segregação espacial em ambientes humanos associando-se preferencialmente com os vertebrados que exploram na natureza. Assim, conclue-se que a partição de recursos, e não a verdadeira competição interespecífica, provavelmente impulsiona a segregação ecológica de T. brasiliensis e T. ix pseudomaculata em habitats criados pelo homem. Elucidar os mecanismos subjacentes ao particionamento de recursos exigirá abordagens experimentais.Triatoma brasiliensis and Triatoma pseudomaculata are vectors of Trypanosoma cruzi, the agent of Chagas disease, in the Caatinga of northeastern Brazil. In the wild, these species occupy different ecotopes and exploit different hosts. The ground-dwelling T. brasiliensis is associated with rocky outcrops (and cacti in some areas) often shared by rodents, whereas T. pseudomaculata is arboreal and appears to feed mainly on birds. Both species, however, can infest man-made habitats, where the possibility arises for competition over key resources \2013 shelter and blood. We determined T. brasiliensis and T. pseudomaculata occurrence/co-occurrence in 412 man-made ecotopes (91 dwellings) to investigate species-segregation patterns and to probe two candidate underlying processes: (a) resource partitioning (T. brasiliensis preferring mineral or rodent-occupied ecotopes and T. pseudomaculata preferring vegetal or fowl-occupied ecotopes) and (b) true interspecies competition (each species effectively avoiding the other). We used generalized linear mixed models (GLMMs) to identify correlates of species-specific occurrence including the other species\2019 co-occurrence. Both species co-occurred in four ecotopes (0.97%). T. brasiliensis (overall occurrence 12.9%) was more common than T. pseudomaculata in mineral ecotopes (17.9% vs. 3.46%) and in ecotopes used by rodents (74.1% vs. 11.1%); the top-performing T. brasiliensis GLMM estimated a strong positive effect of rodent availability on bug occurrence (\03B2rodent=3.55±057SE) In contrast, T. pseudomaculata was overall rarer (7.1%) and occurred more often than T. brasiliensis in vegetal ecotopes (13.6% vs. 6.8%) and in ecotopes used by fowl (19.3% vs. 6.4%); the top-performing T. pseudomaculata GLMM estimated the effect of fowl presence on bug occurrence as \03B2fowl=2.30±0.48SE. GLMMs revealed no evidence that one species\2019 occurrence affected the probability that the other co-occurred in the same ecotope, after adjusting for ecotope traits and host availability. These findings suggest that our study species maintain spatial segregation in human environments by preferentially associating with the vertebrates they exploit in nature. It is concluded that resource partitioning, and not true interspecies competition, likely drives ecological segregation of T. brasiliensis and T. pseudomaculata in man-made habitats. Elucidating the mechanisms underlying resource partitioning will require experimental approaches
Variabilidade genética em populações de Aedes aegypti (Diptera:Culicidae)
No full textO principal vetor do vírus Dengue é o Aedes aegypti, uma espécie originária da África. A presença do vetor nas Américas data dos séculos XVII-XVIII; a primeira introdução no Brasil aconteceu, provavelmente, no início do século XIX. Contudo, o processo de invasão do continente por Ae. aegypti ainda é mal compreendido, e as relações entre as dinâmicas de introdução/estabelecimento/expansão do vetor e as tendências epidemiológicas da doença não têm sido avaliadas de forma detalhada. Neste trabalho estamos uma série de hipóteses sobre as origens, número e dinâmicas espaciais e temporais da invasão das Américas por Ae. aegypti. As predições-chave foram testadas utilizando uma base de mais de 3000 seqüências de um fragmento do gene ND4 mitocondrial. Esta base, compilada e completada durante o desenvolvimento deste projeto, contém dados de espécimes de cinco regiões das Américas (desde os Estados Unidos até o Sul do Brasil), da África e da Ásia. As análises incluíram os seguintes aspectos: (i) diversidade genética; (ii) padrões espaciais de ocorrência de diferentes haplótipos; (iii) relações genealógicas e filogenéticas; (iv) estruturação genética populacional; e (v) demografia histórica. Os resultados sugerem dois eventos principais, provavelmente antigos, de introdução de Aedes aegypti nas Américas. Ambos envolveram a chegada inicial de populações africanas moderadamente diferenciadas à região do Caribe/Norte-Mesoamérica. Uma destas linhagens se dispersou até a Venezuela e avançou para o sul em duas ondas. A primeira onda alcançou o norte da Amazônia, onde algumas sub-populações ficaram isoladas; sugerimos que a dispersão destes vetores foi a responsável pela primeira pandemia americana de dengue (1824-1828). A
segunda onda, muito mais recente, resultou na colonização de grande parte da América do Sul. A segunda linhagem, pelo contrário, alcançou o continente Sul-americano pelo Sudeste do Brasil, e se dispersou em direção norte durante a segunda pandemia (1845-1851); a persistência desta linhagem no país sugere que as campanhas de erradicação nunca alcançaram seu objetivo. O encontro secundário dos descendentes das duas linhagens principais é responsável pelo padrão repetidamente reportado de alta diversidade genética das populações locais. Os dados sugerem que a dispersão passiva do vetor e os efeitos das ações de controle geram um padrão de forte estruturação genética. Em conjunto, os dados genéticos e a evolução recente do perfil epidemiológico da dengue no Brasil indicam que a efetividade das intervenções de controle se viu comprometida pelo processo de descentralização do sistema de saúde nos anos 1990. Finalmente, mostramos como os resultados das análises genéticas podem ajudar no desenho de melhores estratégias de controle e vigilância; eles podem ajudar a identificar sub-populações mais invasivas ou mais diversas do vetor, ou a definir pontos críticos para o controle-vigilância entomológicos. Os dados sugerem que estas intervenções serão importantes inclusive em localidades já colonizadas pelo vetor. Em definitiva, temos desenvolvido, utilizando dados sobre variabilidade genética populacional, uma proposta capaz de dar conta do processo de invasão das Américas por Aedes aegypti e estabelecido as possíveis correspondências entre os padrões de diversidade genética desta espécie de vetor e as dinâmicas espaciais e temporais da epidemiologia da dengue no Brasil.The most important vector of Dengue virus is Aedes aegypti, an originally African th mosquito species. The presence of this vector in the Americas dates back to the 17-18 centuries; it is thought to have been first introduced into Brazil by the beginning of the th20 century. However, the process of invasion of the continent by Ae. aegypti remains poorly understood, and the relationships between the dynamics of vector introduction/establishment/expansion and dengue epidemiological trends have not been thoroughly assessed. Here we test a series of hypotheses regarding the origins, number, and spatial and temporal dynamics of the invasion of the Americas by Ae. aegypti. Key
predictions were tested using a database composed of over 3000 mitochondrial ND4 gene sequences. This database, which was compiled and completed in the course of the project, contains sequences from specimens collected in five regions of the Americas (from the United States to southern Brazil), in Africa, and in Asia. Analyses covered the
following subjects: (i) genetic diversity; (ii) spatial patterns of haplotype occurrence; (iii) genealogical and phylogenetic relationships; (iv) population genetic structuring; and (v) historical demography. Results suggest two major, probably old events of Aedes
aegypti introduction into the Americas. Both involved the early arrival of moderately divergent African populations to the Caribbean and North-Mesoamerica. One of these lineages dispersed to Venezuela and spread southwards in two invasion waves. The first wave reached northern Amazonia, where some sub-populations became isolated; we suggest that the spread of these vectors was involved in the first American dengue pandemic (1824-1828). The second, much more recent wave resulted in the colonization of most of South America by this lineage. In contrast, the second major lineage reached South America by the Brazilian Southeastern region, and dispersed northwards during
the second pandemic (1845-1851); the persistence of this lineage in Brazil suggests that eradication campaigns were never completely successful. The secondary encounter of the descendants of both major lineages gave rise to the often-reported pattern of high genetic diversity. The data suggest that passive vector dispersal and the effects of control interventions on local populations produce a pattern of strong genetic structuring. The recent evolution of dengue epidemiological patterns in Brazil suggests that health sector reform and decentralization in the 1990s limited the efficacy of control interventions. We finally suggest how the results of studies on vector genetics can be incorporated into the design of better control-surveillance strategies; they can help identify more invasive or more diverse vector populations, or help define critical locations for entomological surveillance and control. Our data show how these interventions should be pursued even in localities already infested by the vector. We have developed, making use of data on population genetic variability, a comprehensive proposal on the process of invasion of the Americas by Aedes aegypti, and tentatively established the correspondence between the patterns of genetic diversity of this vector species and the spatial and temporal dynamics of dengue epidemiology in Brazil
The ecology and genetics of Chagas disease vectors in Ecuador, with emphasis on Rhodnius ecuadoriensis (Hemiptera : Reduviidae : Triatominae)
Get PDFAn estimate >11 million people are
infected
by
Trypanosoma
cruzi
in
Latin America.
Chagas disease control programmes have been
successful
in the
Southern
Cone
countries,
and similar initiatives are underway in the
Andean
countries.
In Ecuador
prevalence
is
estimated as ~ 130000 people, with 2.5-3.8 million
at risk;
annual
associated costs
may
reach >20 million US dollars. We studied ecological,
genetic,
and evolutionary aspects of
Rhodnius ecuadoriensis, an important disease vector
in
western
Ecuador
and northwestern
Peru. Sylvatic and synanthropic populations are sympatric
in
central
Ecuador;
only
domestic-peridomestic colonies occur in the temperate
Andean
valleys of southern
Ecuador
and northern Peru. Both morphological-chromatic
features
and
ecological-behavioural
preferences seem to define a cline [sylvatic-large (north)
- synanthropic-small (south)].
The ecology of domestic and sylvatic populations
was
studied
using
logistic
regression.
Phytelephas aequatorialis palms are the primary
natural ecotope of
R
ecuadoriensis;
sylvatic bugs tend to favour male palms with
large
amounts of
decomposing
organic
material and located in cropland/pasture
fields.
Poor
households
with
mud
walls,
tiled
roofs
and large numbers of chickens were more
likely to
be infested. Isometry-free
morphometric
analysis consistently achieved >90% correct
discrimination
of sylvatic
vs.
synanthropic
populations, supporting the use of metric variables
in
surveillance
of reinfestations; size-free analyses revealed substantial divergence of
Peruvian
bugs from
La Libertad.
Mitochondrial DNA sequence polymorphisms (cytochrome b
gene,
663
basepairs)
were
analysed; ~4% sequence divergence scored
between
Ecuadorian
and
Peruvian
populations
suggested they are independent phylogroups. Haplotype
diversity
and relationships
indicate
central coastal Ecuador as the centre of
dispersal
of this
species,
with
isolated
domestic
populations in dry Andean valleys. The phylogeny
of this
species was
explored
using
morphometric and molecular approaches.
The
monophyly
of the
`Pacific Rhodnius lineage'
(pallescens, colombiensis and ecuadoriensis) was confirmed,
with
the
parapatric
pallescens
and colombiensis being very closely related;
R.
pictipes
is the
closest relative to this
lineage
among Amazonian species, with the robustus group
forming
a
distinct,
major
Glade.
Control of R ecuadoriensis can contemplate
local
eradication
in dry
Andean
valleys
(southern Ecuador and northern Peru); special
attention
should
be
paid to
peridomestic
populations, including improvement of poultry
management
(burning-replacing
nests every
15-30 days). Long-term interruption of
disease transmission
would
benefit from
educational
interventions increasing awareness about Chagas
disease
and
from
housing improvements
targeting mud walls and timber-and-tile roofs.
In
central-northern
western
Ecuador
peridomestic palm trees may be the origin of
reinfestations;
environmental
management
(removing dead fronds and fibres from peridomestic
palms),
and
continuous
community-
based surveillance are recommended.
A
comprehensive
control
programme
over
15
years
would probably result in interruption of
disease transmission,
and
could
bring
savings of
about 20 US$ per each dollar invested
A simple, biologically sound, and potentially useful working classification of Chagas disease vectors
Get PDFFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, BrasilCurrent working classifications of Chagas disease vectors rely on a loose mix-up of biological and operational matters. They are therefore confusing and ineffective. I propose a very simple classification that makes biological sense and can be operationally useful. It considers a four-level hierarchy of species (which can be native or non-native); populations (either wild or non-wild); infestation foci (natural, domestic or peridomestic); and individual bugs (which can be solitary house-invaders or part of a hidden infestation focus). This classification translates into a clear, algorithmic scheme for triatomine control-surveillance that may be useful at every operationally relevant scale, from multi-country initiatives to on-site control-surveillance action
Transciones ecológicas y transmisión vectorial de la enfermedad de chagas en la Amazonia
No full textReunión: Segunda (II) reunión de la Iniciativa Intergubernamental de Vigiliancia y Prevención de la enfermedad de Chagas en la Amazonia (AMCHA II), 2-4 Nov. 2005, Cayenne, G
The ecology and genetics of Chagas disease vectors in Ecuador, with emphasis on Rhodnius ecuadoriensis (Hemiptera: Reduviidae: Triatominae)
Get PDFAn estimate >11 million people are infected by Trypanosoma cruzi in Latin America. Chagas disease control programmes have been successful in the Southern Cone countries, and similar initiatives are underway in the Andean countries. In Ecuador prevalence is estimated as ~ 130000 people, with 2.5-3.8 million at risk; annual associated costs may reach >20 million US dollars. We studied ecological, genetic, and evolutionary aspects of Rhodnius ecuadoriensis, an important disease vector in western Ecuador and northwestern Peru. Sylvatic and synanthropic populations are sympatric in central Ecuador; only domestic-peridomestic colonies occur in the temperate Andean valleys of southern Ecuador and northern Peru. Both morphological-chromatic features and ecological-behavioural preferences seem to define a cline [sylvatic-large (north) - synanthropic-small (south)]. The ecology of domestic and sylvatic populations was studied using logistic regression. Phytelephas aequatorialis palms are the primary natural ecotope of R ecuadoriensis; sylvatic bugs tend to favour male palms with large amounts of decomposing organic material and located in cropland/pasture fields. Poor households with mud walls, tiled roofs and large numbers of chickens were more likely to be infested. Isometry-free morphometric analysis consistently achieved >90% correct discrimination of sylvatic vs. synanthropic populations, supporting the use of metric variables in surveillance of reinfestations; size-free analyses revealed substantial divergence of Peruvian bugs from La Libertad. Mitochondrial DNA sequence polymorphisms (cytochrome b gene, 663 basepairs) were analysed; ~4% sequence divergence scored between Ecuadorian and Peruvian populations suggested they are independent phylogroups. Haplotype diversity and relationships indicate central coastal Ecuador as the centre of dispersal of this species, with isolated domestic populations in dry Andean valleys. The phylogeny of this species was explored using morphometric and molecular approaches. The monophyly of the `Pacific Rhodnius lineage' (pallescens, colombiensis and ecuadoriensis) was confirmed, with the parapatric pallescens and colombiensis being very closely related; R. pictipes is the closest relative to this lineage among Amazonian species, with the robustus group forming a distinct, major Glade. Control of R ecuadoriensis can contemplate local eradication in dry Andean valleys (southern Ecuador and northern Peru); special attention should be paid to peridomestic populations, including improvement of poultry management (burning-replacing nests every 15-30 days). Long-term interruption of disease transmission would benefit from educational interventions increasing awareness about Chagas disease and from housing improvements targeting mud walls and timber-and-tile roofs. In central-northern western Ecuador peridomestic palm trees may be the origin of reinfestations; environmental management (removing dead fronds and fibres from peridomestic palms), and continuous community- based surveillance are recommended. A comprehensive control programme over 15 years would probably result in interruption of disease transmission, and could bring savings of about 20 US$ per each dollar invested.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Ecologia de Rhodnius nasutus Stål 1859 (Hemiptera: Reduviidae: Triatominae) em palmeiras da Chapada do Araripe, Ceará, Brasil, Brasil.
No full textConsidera-se que
Rhodnius nasutus
Stål, 1859 seja um triatomíneo restrito ao
domínio da caatinga. Entr
etanto, seus limites não estão bem reconhecidos. O
objetivo do presente trabalho
foi identificar qual espécie de triatomíneo ocorre
ao sul do estado do Ceará, nas palmeiras
da Chapada do Araripe, Brasil e sua
importância na transmissão local pelo
Trypanosoma cruzi
e
Trypanosoma
rangeli
. Embora esteja incluída no contexto da caatinga, esta região é
considerada uma área com vegetação mi
sta de cerrado e Mata Atlântica.
Sendo as diversas espécies de palmeiras relatadas como ecótopo para
triatomíneos do gênero
Rhodnius
, foram trabalhadas cinco espécies de
palmeiras, num total de 10 exemplares
para cada espécie, a saber: babaçu
(
Attalea speciosa
), buriti (
Mauritia flexuosa
), carnaúba (
Copernicia prunifera
),
catolé (
Syagrus oleracea
) e macaúba-barriguda (
Acrocomia intumescens
). A
única espécie de triatomíneo encontrada foi
R. nasutus
, e o índice de
infestação global foi de 86%
. No Ceará, esta espécie tem sido encontrada
freqüentemente no peridomicílio e intradomicílio, demonstrando significativa
importância na DC. O índice
de infecção encontrado pelo
Trypanosoma cruzi
foi de 16,8% e, pela primeira vez na lit
eratura, relatamos a ocorrência do
Trypanosoma rangeli
no estado do Ceará, com í
ndice de infecção natural de
7,7%, nos insetos analisados. Os tripanosomatídeos foram caracterizados
molecularmente, confirmando os achados
microscópicos, sendo as cepas de
T.
cruzi
pertencentes ao grupo I, característico de cepas circulantes do ambiente
silvestre. Estudos da reaç
ão de precipitina
sugerem que as pr
incipais fontes
alimentares do
R. nasutus
são ave e gambá. As ár
vores UPGMA geradas pela
análise morfométrica apontam
o grupo de insetos dos buritis como o mais
distante geneticamente, o que
pode estar relacionado ao isolamento geográfico
deste grupo de insetos aos demais. Nossos resultados associados aos
enormes palmeirais encontrados na regi
ão da Chapada do Arar
ipe fazem desta
uma importante região endêmica da tr
ipanosomíase americana silvestreRhodnius nasutus
Stål, 1859 is considered a tria
tomine restricted to “caatinga”
regions. However, their occurrence restri
ctions are still un
known. The purpose
of this work was to identify which triatomine species occurs in the south of
Ceará state, in palm tr
ees of Chapada do Araripe, Br
azil and its importance in
the local transmission of
Trypanosoma cruzi
and
Trypanosoma rangeli
. In spite
of being included in
the “caatinga” environment, th
is region is considered an
area with a mixed vegetation of “cerrado”
and “Mata Atlântica” (Atlantic Forest).
As the most diverse species of palm
trees are reported as ecotopes for
triatomines from the genus
Rhodnius
, were studied five species of palm trees,
with a total of 10 specimens of eac
h species, as follows: “babaçu” (
Attalea
speciosa
), “buriti” (
Mauritia flexuosa
), “carnaúba” (
Copernicia prunifera
), “catolé”
(
Syagrus oleracea
) and “macaúba-barriguda” (
Acrocomia intumescens
). The
only triatomine species found was
R. nasutus
, and a global infestation rate was
86%. In Ceará, this species has oft
en been found in the peridomicile and
intradomicile, playing
a significant role in Chagas disease.
Trypanosoma cruzi
’s
infection rate was 16.8% and, for the first time in the literature,
Trypanosoma
rangeli
was reported to occur in the state of
Ceará, with a natur
al infection rate
of 7.7%, in the insects analyzed.
Trypanosomatids were molecularly
characterized, corroborating microscopic findings, with
T. cruzi
strains
belonging to group I, charac
teristic of circulating strains from a sylvatic
environment. Studies on precipitin reaction
suggest that the most important food
resources of
R. nasutus
are birds and opossums. UPGMA trees generated by
morphometric analysis point to a group of in
sects of “buritis” as the most distant
ones, which may be related to the geographic
isolation of this group of insects
compared to the other ones. Our results
associated with lar
ge areas of palm
trees found in the region
of Chapada do Araripe make this an important
endemic region of sylvatic American trypanosomiasis
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