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PLoS Neglected Tropical Diseases Feb 2024Chagas disease, caused by the protozoan parasite Trypanosoma cruzi transmitted by blood-sucking insects of the subfamily Triatominae, is a major neglected tropical...
The interplay between temperature, Trypanosoma cruzi parasite load, and nutrition: Their effects on the development and life-cycle of the Chagas disease vector Rhodnius prolixus.
Chagas disease, caused by the protozoan parasite Trypanosoma cruzi transmitted by blood-sucking insects of the subfamily Triatominae, is a major neglected tropical disease affecting 6 to 7 million of people worldwide. Rhodnius prolixus, one of the most important vectors of Chagas disease in Latin America, is known to be highly sensitive to environmental factors, including temperature. This study aimed to investigate the effects of different temperatures on R. prolixus development and life-cycle, its relationship with T. cruzi, and to gather information about the nutritional habits and energy consumption of R. prolixus. We exposed uninfected and infected R. prolixus to four different temperatures ranging from 24°C to 30°C, and monitored their survival, developmental rate, body and blood meal masses, urine production, and the temporal dynamics of parasite concentration in the excreted urine of the triatomines over the course of their development. Our results demonstrate that temperature significantly impacts R. prolixus development, life-cycle and their relationship with T. cruzi, as R. prolixus exposed to higher temperatures had a shorter developmental time and a higher mortality rate compared to those exposed to lower temperatures, as well as a lower ability to retain weight between blood meals. Infection also decreased the capacity of the triatomines to retain weight gained by blood-feeding to the next developmental stage, and this effect was proportional to parasite concentration in excreted urine. We also showed that T. cruzi multiplication varied depending on temperature, with the lowest temperature having the lowest parasite load. Our findings provide important insights into the potential impact of climate change on the epidemiology of Chagas disease, and can contribute to efforts to model the future distribution of this disease. Our study also raises new questions, highlighting the need for further research in order to understand the complex interactions between temperature, vector biology, and parasite transmission.
Topics: Humans; Animals; Trypanosoma cruzi; Rhodnius; Temperature; Insect Vectors; Chagas Disease; Life Cycle Stages; Parasite Load
PubMed: 38306403
DOI: 10.1371/journal.pntd.0011937 -
Parasites & Vectors Jan 2024Chagas disease is a neglected tropical disease (NTD). Cost-effective strategies for large-scale implementation of diagnosis and etiological treatment are urgently needed...
BACKGROUND
Chagas disease is a neglected tropical disease (NTD). Cost-effective strategies for large-scale implementation of diagnosis and etiological treatment are urgently needed to comply with NTD control goals. We determined the seroprevalence of Trypanosoma cruzi infection and associated risk factors in a well-defined rural population of Pampa del Indio municipality including creole and indigenous (Qom) households and developed two indices to identify houses harboring infected children.
METHODS
We serodiagnosed and administered a questionnaire to 1337 residents (48.2% of the listed population) in two sections of the municipality (named Areas II and IV) 6-9 years after deploying sustained vector control interventions. Multiple logistic regression models were used to evaluate the relationship between human infection and a priori selected predictors. Two risk indices were constructed based on environmental and serostatus variables, and we used spatial analysis to test whether households harboring T. cruzi-seropositive children were randomly distributed.
RESULTS
The global seroprevalence of T. cruzi infection was 24.8%. Human infection was positively and significantly associated with exposure time to triatomines, the household number of seropositive co-inhabitants, maternal seropositivity for T. cruzi, recent residence at the current house and the presence of suitable walls for triatomine colonization in the domicile. The pre-intervention mean annual force of infection (FOI) was 1.23 per 100 person-years. Creoles from Area IV exhibited the highest seroprevalence and FOI; Qom people from both areas displayed intermediate ones and creoles from Area II the lowest. Three hotspots of infected children were spatially associated with hotspots of triatomine abundance at baseline and persistent house infestation. No child born after vector control interventions was T. cruzi seropositive except for one putative transplacental case. Two simple risk indices (based on self-reported inhabiting an infested house and suitable walls for triatomines or maternal serostatus) identified 97.3-98.6% of the households with at least one T. cruzi-seropositive child.
CONCLUSIONS
We showed strong heterogeneity in the seroprevalence of T. cruzi infection within and between ethnic groups inhabiting neighboring rural areas. Developed indices can be used for household risk stratification and to improve access of rural residents to serodiagnosis and treatment and may be easily transferred to primary healthcare personnel.
Topics: Animals; Child; Humans; Chagas Disease; Risk Factors; Seroepidemiologic Studies; Triatoma; Trypanosoma cruzi; Indigenous Peoples; Argentina
PubMed: 38287434
DOI: 10.1186/s13071-024-06125-8 -
Comparative Biochemistry and... Apr 2024We analyse the developmental and circadian profiles of expression of the genes responsible for ecdysteroidogenesis (Halloween genes) in the PGs of Rhodnius prolixus...
We analyse the developmental and circadian profiles of expression of the genes responsible for ecdysteroidogenesis (Halloween genes) in the PGs of Rhodnius prolixus throughout larval-adult development. Extensive use of in vitro techniques enabled multiple different parameters to be measured in individual PGs. Expression of disembodied and spook closely paralleled the ecdysteroid synthesis of the same PGs, and the ecdysteroid titre in vivo, but with functionally significant exceptions. Various tissues other than PGs expressed one, both or neither genes. Both gonads express both genes in pharate adults (larvae close to ecdysis). Both genes were expressed at low, but significant, levels in UF Rhodnius, raising questions concerning how developmental arrest is maintained in UF animals. IHC confirmed the subcellular localisation of the coded proteins. Gene knockdown suppressed transcription of both genes and ecdysteroid synthesis, with spook apparently regulating the downstream gene disembodied. Transcription of both genes occurred with a daily rhythm (with peaks at night) that was confirmed to be under circadian control using aperiodic conditions. The complex behaviour of the rhythm in LL implied two anatomically distinct oscillators regulate this transcription rhythm. First, the circadian clock in the PGs and second, the circadian rhythm of of Rhodnius PTTH which is released rhythmically from the brain under control of the circadian clock therein, both of which were described previously. We conclude ecdysteroidogenesis in Rhodnius PGs employs a similar pathway as other insects, but its control is complex, involving mechanisms both within and outside the PGs.
Topics: Animals; Ecdysteroids; Rhodnius; Insect Hormones; Circadian Rhythm; Larva
PubMed: 38242349
DOI: 10.1016/j.cbpa.2024.111588 -
Scientific Reports Jan 2024Chagas disease is a leading cause of non-ischemic cardiomyopathy in endemic regions of Central and South America. In Belize, Triatoma dimidiata sensu lato has been...
Chagas disease is a leading cause of non-ischemic cardiomyopathy in endemic regions of Central and South America. In Belize, Triatoma dimidiata sensu lato has been identified as the predominate taxon but vectorial transmission of Chagas disease is considered to be rare in the country. We recently identified an acute case of vector-borne Chagas disease in the northern region of Belize. Here we present a subsequent investigation of triatomines collected around the case-patient's home. We identified yet undescribed species, closely related to Triatoma huehuetenanguensis vector by molecular systematics methods occurring in the peridomestic environment. The identification of a T. cruzi-positive, novel species of Triatoma in Belize indicates an increased risk of transmission to humans in the region and warrants expanded surveillance and further investigation.
Topics: Animals; Humans; Triatoma; Belize; Trypanosoma cruzi; Insect Vectors; Chagas Disease
PubMed: 38228608
DOI: 10.1038/s41598-023-50109-0 -
Zootaxa Dec 2023Brontostoma herczeki sp. nov. is described based on two males from southeastern Brazil (Hemiptera: Heteroptera: Reduviidae: Ectrichodiinae). The male of Brontostoma...
A new species of Brontostoma Kirkaldy, description of the male of Brontostoma bahiensis Gil-Santana, Costa & Marques and notes on Brontostoma doughertyae Gil-Santana et al. (Hemiptera: Heteroptera: Reduviidae: Ectrichodiinae).
Brontostoma herczeki sp. nov. is described based on two males from southeastern Brazil (Hemiptera: Heteroptera: Reduviidae: Ectrichodiinae). The male of Brontostoma bahiensis Gil-Santana, Costa & Marques, 2004 is described based on a specimen from Bahia state, Brazil. Taxonomical notes on Brontostoma doughertyae Gil-Santana, Lopes, Marques & Jurberg, 2005 are provided. Photographs of the holotypes of Brontostoma bahiensis, Brontostoma diringshofeni Gil-Santana & Baena, 2009 and Brontostoma doughertyae are presented.
Topics: Male; Animals; Reduviidae; Heteroptera; Hemiptera; Gastropoda; Animal Distribution
PubMed: 38221275
DOI: 10.11646/zootaxa.5382.1.9 -
Zootaxa Oct 2023The Florida State Collection of Arthropods (FSCA) is one of the largest and most diverse insect collections in North America and the largest in the southeastern United...
The Florida State Collection of Arthropods (FSCA) is one of the largest and most diverse insect collections in North America and the largest in the southeastern United States with over twelve million curated specimens and significant amounts of materials in bulk collections and other unprocessed samples. The order Hemiptera currently comprises approximately 95,000 species in three suborders. The FSCA houses type material in the auchenorrhynchan families Cicadidae, Cicadellidae, Cixiidae, Delphacidae, Derbidae, and Membracidae; the heteropteran families Coreidae, Corixidae, Curaliidae, Lygaeidae, Miridae, Pentatomidae, Reduviidae, Schizopteridae, Scutelleridae, and Tingidae; the sternorrhynchan families Aleyrodidae, Aphalaridae, Aphididae, Coccidae, Diaspididae, Matsucoccidae, Pseudococcidae, Phacopteronidae, and Triozidae. This catalog documents the FSCA primary type material for 167 species in 79 genera in 24 families across the three suborders.
Topics: Humans; Animals; Hemiptera; Florida; Aphids; Reduviidae
PubMed: 38220658
DOI: 10.11646/zootaxa.5355.1.1 -
Acta Tropica Mar 2024How far are we from predicting the occurrence of zoonotic diseases? In this paper we have made use of both socioecological and ecological variables to predict Chagas...
How far are we from predicting the occurrence of zoonotic diseases? In this paper we have made use of both socioecological and ecological variables to predict Chagas disease occurrence. Chagas disease involves, Trypanosoma cruzi, a complex life-cycle parasite which requires two hosts: blood-feeding triatomine insects and vertebrate hosts including humans. We have used a common risk assessment method combined with datasets that imply critical environmental and socioeconomic drivers of Chagas dynamics to predict the occurrence of this disease. We also carried out a network analysis to assess the interactions among triatomines and mammal host species given their human contact via whether hunted, domesticated or associated with anthropogenic landscapes in Mexico. We found that social backwardness variation, lack of health services and altitude had the largest relative influence Chagas events. Triatoma pallidipennis made use of the largest host diversity. Host species shared by the highest number of different triatomines were a woodrat, the highly appreciated bushmeat, and racoon. These results indicate both the predominance of socio-economic factors over ecological ones, and how close we are from predicting zoonotic diseases.
Topics: Animals; Humans; Triatoma; Insect Vectors; Chagas Disease; Trypanosoma cruzi; Mammals; Zoonoses
PubMed: 38215899
DOI: 10.1016/j.actatropica.2023.107098 -
Acta Tropica Mar 2024Exploring the dynamics of disease transmission involves an understanding of complex interactions within the eco-epidemiologic framework. In the context of Chagas disease...
Exploring the dynamics of disease transmission involves an understanding of complex interactions within the eco-epidemiologic framework. In the context of Chagas disease (CD), elements are mainly represented by the interactions among the pathogen, insect vector, host, humans and the environment. We performed quantitative and qualitative analyses on a dataset derived from 98 Triatoma brasiliensis infected by trypanosomatids, which were linked to a CD outbreak in the semi-arid region of northeastern Brazil. We extracted invertebrate-derived DNA (iDNA) from these insects, comprising 18 populations around the outbreak area, each indicative of various strata of anthropogenic influence. Food source (FS) diversity, representing potential parasite reservoirs, was determined through mitochondrial gene (cyt b) sequencing of vertebrates, and parasite genotyping was accessed using fluorescent amplified fragment barcodes (FFLB) of trypanosomatids. We also assessed the residents' awareness of breeding sites for CD vectors in the inspected houses. The quantification of Trypanosoma cruzi was estimated via real-time PCR and is denominated here as the average parasite load (PL) per insect (T. cruzi/intestinal unit). We aimed to address vector-parasite-host-environment interactions that were discussed based on their significance among the components. Notably, among the significant interactions, we observed that the PL in the insects was significantly influenced by FS. Infected insects that fed on the classic reservoir, Didelphis albiventris, and Galea spixii exhibited higher PLs, compared to those that fed on Kerodon rupestris (p < 0.04)-a primary host. While D. albiventris is already recognized as a synanthropic species, we propose that G. spixii may also be undergoing a synanthropic process. Conversely, domestic cats are frequently identified as FS in infected insects from the sylvatic environment, suggesting a possible change in their behavior towards a wild state. Therefore, we propose that neglected anthropogenic actions have facilitated the reciprocal (sylvatic-peridomestic) circulation of T. cruzi-especially noted for TcI because it was predominant in insects found in peridomestic environments. Residents are often unaware of the existence of insect breeding grounds near their homes, particularly when it involves the storage of materials without planning for use, such as piles of tiles, bricks and wood. Although indirect inferences about the interaction among vector-parasite-host-environment are still incipient, we highlight the potential use of vectors as natural samplers of biological and ecological components in transmitting the disease.
Topics: Humans; Animals; Cats; Triatoma; Ecosystem; Chagas Disease; Trypanosoma cruzi; Disease Outbreaks; Rodentia; Didelphis
PubMed: 38190930
DOI: 10.1016/j.actatropica.2023.107107 -
Scientific Reports Jan 2024Morphological studies applied to the taxonomy of the Triatominae cover various structures (head, wing, thorax, genitalia, and eggs). Exochorial structures of hybrid eggs...
Morphological studies applied to the taxonomy of the Triatominae cover various structures (head, wing, thorax, genitalia, and eggs). Exochorial structures of hybrid eggs were characterized and compared with the parents, demonstrating that hybrids presented characteristics identical to the exochorial pattern observed in the females of the crosses, which resulted in the hypothesis that the pattern of triatomine eggs is possibly a characteristic inherited from females. Thus, we characterized the exochorium of the eggs of several triatomine hybrids and compared them with the parents, to assess the pattern of segregation and test the hypothesis of maternal inheritance. Hybrids were obtained in at least one direction from all crosses. The analysis of the exochorium of the eggs of the hybrids showed different patterns of segregation: "exclusively paternal", "predominantly maternal", "predominantly paternal", "mutual", and "differential". Curiously, none of the hybrids evaluated presented characteristics that segregated exclusively from the female parental species. Thus, we demonstrate that the hypothesis of maternal inheritance of the exochorium pattern of eggs is not valid and we emphasize the importance of alternative/combined tools (such as integrative taxonomy) for the correct identification of these insect vectors (mainly in view of possible natural hybridization events due to climate and environmental changes).
Topics: Animals; Female; Maternal Inheritance; Chagas Disease; Triatominae; Climate; Insect Vectors
PubMed: 38184729
DOI: 10.1038/s41598-023-51125-w -
Acta Tropica Mar 2024Drivers for wildlife infection are multiple and complex, particularly for vector-borne diseases. Here, we studied the role of host competence, geographic area...
Drivers for wildlife infection are multiple and complex, particularly for vector-borne diseases. Here, we studied the role of host competence, geographic area provenance, and diversity of vector-host interactions as drivers of wild mammal infection risk to Trypanosoma cruzi, the aetiological agent of Chagas disease. We performed a systematic sampling of wild mammals in 11 states of Mexico, from 2017 to 2018. We tested the positivity of T. cruzi with the Tc24 marker in tissues samples for 61 wild mammal species (524 specimens sampled). 26 mammal species were positive for T. cruzi, of which 11 are new hosts recorded in Mexico 75 specimens were positive and 449 were negative for T. cruzi infection, yielding an overall prevalence of 14.3%. The standardized infection risk of T. cruzi of our examined specimens was similar, no matter the host species or their geographic origins. Additionally, we used published data of mammal positives for T. cruzi to complement records of T. cruzi infection in wild mammals and inferred a trophic network of Triatoma spp. (vectors) and wild mammal species in Mexico, using spatial data-mining modelling. Infection with T. cruzi was not homogeneously distributed in the inferred trophic network. This information allowed us to develop a predictive model for T. cruzi infection risk for wild mammals in Mexico, considering risk as a function of the diversity of vector-host spatial associations in a large-scale geographic context, finding that the addition of competent vectors to a multi-host parasite system amplifies host infection risk. The diversity of vector-host interactions per se constitutes a relevant driver of infection risk because hosts and vectors are not isolated from each other.
Topics: Animals; Trypanosoma cruzi; Animals, Wild; Chagas Disease; Triatoma; Mammals; Zoonoses; Geography
PubMed: 38184291
DOI: 10.1016/j.actatropica.2024.107117