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PLoS Neglected Tropical Diseases Oct 2023Vector-borne diseases remain a significant public health threat in many regions of the world. Traditional vector surveillance and control methods have relied on active...
Vector-borne diseases remain a significant public health threat in many regions of the world. Traditional vector surveillance and control methods have relied on active and passive surveillance programs, which are often costly and time-consuming. New internet-based vector surveillance systems have shown promise in removing some of the cost and labor burden from health authorities. We developed and evaluated the effectiveness of a new internet-based surveillance system, "AlertaChirimacha", for detecting Triatoma infestans (known locally by its Quechua name, Chirimacha), the Chagas disease vector, in the city of Arequipa, Peru. In the first 26 months post-implementation, AlertaChirimacha received 206 reports of residents suspecting or fearing triatomines in their homes or neighborhoods, of which we confirmed, through pictures or inspections, 11 (5.3%) to be Triatoma infestans. After microscopic examination, none of the specimens collected were infected with Trypanosoma cruzi. AlertaChirimacha received 57% more confirmed reports than the traditional surveillance system and detected 10% more infested houses than active and passive surveillance approaches combined. Through in-depth interviews we evaluate the reach, bilateral engagement, and response promptness and efficiency of AlertaChirimacha. Our study highlights the potential of internet-based vector surveillance systems, such as AlertaChirimacha, to improve vector surveillance and control efforts in resource-limited settings. This approach could decrease the cost and time horizon for the elimination of vector-mediated Chagas disease in the region.
Topics: Animals; Humans; Chagas Disease; Triatoma; Trypanosoma cruzi; Insect Vectors; Peru
PubMed: 37844066
DOI: 10.1371/journal.pntd.0011694 -
Frontiers in Endocrinology 2023Within insects, corticotropin-releasing factor/diuretic hormones (CRF/DHs) are responsible for the modulation of a range of physiological and behavioural processes such...
Within insects, corticotropin-releasing factor/diuretic hormones (CRF/DHs) are responsible for the modulation of a range of physiological and behavioural processes such as feeding, diuresis, and reproduction. Rhopr-CRF/DH plays a key role in feeding and diuresis in , a blood-gorging insect and a vector for human Chagas disease. Here, we extend our understanding on the role of this neurohormone in reproduction in adult female . Double-label immunohistochemistry displays co-localized staining of CRF-like and the glycoprotein hormone (GPA2/GPB5) subunit GPB5-like immunoreactivity in the same neurosecretory cells (NSCs) in the mesothoracic ganglionic mass (MTGM) and in their neurohemal sites in adult female , suggesting these peptides could work together to regulate physiological processes. qPCR analysis reveals that the transcript for Rhopr-CRF/DH receptor 2 () is expressed in reproductive tissues and fat body (FB) in adult female , and its expression increases post blood meal (PBM), a stimulus that triggers diuresis and reproduction. Using RNA interference, transcript expression of was knocked down, and egg production monitored by examining the major yolk protein, vitellogenin (Vg), the number and quality of eggs laid, and their hatching ratio. Injection of dsCRFR2 into adult females reduces transcript expression, accelerates oogenesis, increases the number of eggs produced, and reduces hatching rate in female . Downregulation of leads to an increase in the transcript expression of in the fat body and ovaries, and increases the transcript level for the Vg receptor, , in the ovaries. A significant increase in Vg content in the fat body and in the hemolymph is also observed. Incubation of isolated tissues with Rhopr-CRF/DH leads to a significant decrease in transcript expression of in the fat body and in the ovaries. In addition, Rhopr-CRF/DH reduces transcript expression of the ecdysteroid biosynthetic enzymes and reduces ecdysteroid titer in the culture medium containing isolated ovaries. These results suggest the involvement of the CRF-signaling pathway in reproduction, and that Rhopr-CRF/DH acts as a gonad-inhibiting hormone in the adult female , as previously shown for the colocalized glycoprotein, GPA2/GPB5.
Topics: Animals; Female; Adult; Humans; Corticotropin-Releasing Hormone; Diuretics; Rhodnius; Ecdysteroids; Gonadal Hormones; Glycoproteins; Gonads
PubMed: 37842303
DOI: 10.3389/fendo.2023.1279929 -
Current Research in Parasitology &... 2023Triatomines (Hemiptera: Reduviidae: Triatominae), commonly called "kissing bugs", are blood-sucking pests and vectors of the protozoan parasite , the causative agent of... (Review)
Review
Triatomines (Hemiptera: Reduviidae: Triatominae), commonly called "kissing bugs", are blood-sucking pests and vectors of the protozoan parasite , the causative agent of Chagas disease (CD). Eleven species of kissing bugs occur throughout the southern half of the USA, four of which are well known to invade human dwellings. Certain kissing bugs in the USA are known to transmit to humans and other animals and their bites can also lead to serious allergic reactions, including anaphylaxis. In Florida, the kissing bug frequently invades homes, bites residents, and has been found infected with , placing humans and companion animals at risk for CD. This review outlines integrated pest management (IPM) strategies for minimizing human exposure to and CD. A comprehensive IPM plan for kissing bugs includes detailed inspections, removal of vertebrate host nesting areas, and kissing bug harborage, home improvements to exclude kissing bugs from entering structures, pest removal, and judicious use of pesticides. This approach can limit or eliminate kissing bug entry into residential structures, thereby preventing kissing bug bites, and CD infections in humans and companion animals.
PubMed: 37841307
DOI: 10.1016/j.crpvbd.2023.100144 -
ZooKeys 2023is described. Taxonomic notes on the other species of Barber, 1930, including the description of their male genitalia, are provided. The record of Barber, 1930 from...
A new species of Barber, with a redescription of the genus, taxonomic notes, and a key to the species of the genus (Hemiptera, Heteroptera, Reduviidae, Stenopodainae).
is described. Taxonomic notes on the other species of Barber, 1930, including the description of their male genitalia, are provided. The record of Barber, 1930 from Brazil and information about the female of the species are presented for the first time. A redescription of and a key for its species are provided. Photographs of the holotypes of (Costa Lima, 1941), , and of a paratype of Maldonado & Bérenger, 1996 are presented.
PubMed: 37841028
DOI: 10.3897/zookeys.1181.108463 -
Revista Da Sociedade Brasileira de... 2023An external quality assessment on the identification of triatomines within the laboratory network in the state of Rondônia.
BACKGROUND
An external quality assessment on the identification of triatomines within the laboratory network in the state of Rondônia.
METHODS
Seven laboratories participated in this evaluation. Each was provided with support materials and nine insects from the Hemiptera order for identification.
RESULTS
All samples were accurately identified at the species level. However, correct sex identification was achieved for only 79% of the samples. The most significant challenges were encountered in determining the sex of predators, phytophagous species, Rhodnius robustus, and Rhodnius pictipes.
CONCLUSIONS
The identified shortcomings can inform enhancements in vector control programs for Chagas disease.
Topics: Animals; Brazil; Laboratories; Chagas Disease; Environment; Rhodnius; Trypanosoma cruzi
PubMed: 37792830
DOI: 10.1590/0037-8682-0211-2023 -
The American Journal of Tropical... Nov 2023Chagas disease is a health concern for humans and animals across the Americas, and control options targeting the triatomine vectors of Trypanosoma cruzi, the causative...
Chagas disease is a health concern for humans and animals across the Americas, and control options targeting the triatomine vectors of Trypanosoma cruzi, the causative agent of Chagas disease, are limited. Host-targeted interventions may be a useful and underused tool in controlling the spread of T. cruzi from vectors to hosts. Domestic dogs are known to be key bloodmeal hosts for triatomines as well as T. cruzi reservoirs and may be an effective and practical target for host-targeted insecticide deployment. We hypothesized that treating dogs with commercially available systemic insecticides (labeled for flea and tick control) would result in mortality of triatomines after consuming treated blood. We enrolled 16 privately owned dogs into five treatment groups to receive either fluralaner (Bravecto) or lotilaner (Credelio), alone or in combination with ivermectin. Blood from dogs before the initiation of treatment served as controls. Blood was collected 0, 7, 30, 45, and 90 days after the initial canine insecticide treatment and fed to 10 Triatoma gerstaeckeri nymphs through a membrane feeder, and survival was tracked daily for 7 days and weekly thereafter. All triatomines in the control and ivermectin groups survived the initial period, with no significant difference in long-term survival. In contrast, 99.7% of triatomines that fed on blood from dogs treated with either fluralaner or lotilaner died within 3 days. Although the impact of canine treatment on suppressing vector populations is unknown, fluralaner and lotilaner appear to be a compelling option for an integrated vector management approach to triatomine control.
Topics: Animals; Dogs; Humans; Triatoma; Insecticides; Parasites; Ivermectin; Insect Vectors; Chagas Disease; Trypanosoma cruzi; North America
PubMed: 37748769
DOI: 10.4269/ajtmh.23-0300 -
PLoS Neglected Tropical Diseases Sep 2023The blood-sucking hemipteran Rhodnius prolixus is one of the main vectors of Chagas disease, a neglected tropical disease that affects several million people worldwide....
The blood-sucking hemipteran Rhodnius prolixus is one of the main vectors of Chagas disease, a neglected tropical disease that affects several million people worldwide. Consuming a blood meal and mating are events with a high epidemiological impact since after each meal, mated females can lay fertile eggs that result in hundreds of offspring. Thus, a better knowledge of the control of R. prolixus reproductive capacity may provide targets for developing novel strategies to control vector populations, thereby reducing vector-host contacts and disease transmission. Here, we have used a combination of gene transcript expression analysis, biochemical assays, hormone measurements and studies of locomotory activity to investigate how mating influences egg development and egg laying rates in R. prolixus females. The results demonstrate that a blood meal increases egg production capacity and leads to earlier egg laying in mated females compared to virgins. Virgin females, however, have increased survival rate over mated females. Circulating juvenile hormone (JH) and ecdysteroid titers are increased in mated females, a process mainly driven through an upregulation of the transcripts for their biosynthetic enzymes in the corpus allatum and ovaries, respectively. Mated females display weaker locomotory activity compared to virgin females, mainly during the photophase. In essence, this study shows how reproductive output and behaviour are profoundly influenced by mating, highlighting molecular, biochemical, endocrine and behavioral features differentially expressed in mated and virgin R. prolixus females.
Topics: Animals; Female; Humans; Rhodnius; Parasites; Chagas Disease; Reproduction; Oviposition
PubMed: 37729234
DOI: 10.1371/journal.pntd.0011640 -
New Microbes and New Infections Sep 2023The blood-feeding behavior of kissing bugs (subfamily Triatominae, family Reduviidae, order Hemiptera) means they are potential vectors of multiple humans pathogens....
BACKGROUND
The blood-feeding behavior of kissing bugs (subfamily Triatominae, family Reduviidae, order Hemiptera) means they are potential vectors of multiple humans pathogens. However, investigations of vector-borne pathogens harbored by kissing bugs are rare.
METHODS
In the current study, 22 adult kissing bugs () were captured in Huizhou City, Guangdong Province, south China. The presence of vector-borne pathogens in the kissing bugs was tested, and the genetic diversity of these potential pathogens was investigated.
RESULTS
All the kissing bugs were negative for Anaplasmataceae bacteria, , and . DNA was detected in 36.4% (8/22) of the kissing bugs. The sequences of the genes divided into two clades in a phylogenetic tree, with close relationships to and uncultured sp. clone MYR-283, respectively. All the sequences were closely related to those of (identity 98.75%-100%). The and sequences were most closely related to those of , a recognized human pathogen, with nucleotide similarities of 98.70%-100% and 99.45%-100%, respectively.
CONCLUSIONS
We report the detection of DNA in kissing bugs in southern China. Although the sample size is limited, the high positive rate of detection of DNA, the close relationship of the gene sequences to those of zoonotic species, and the distribution of the kissing bugs near human residences, hint at a risk to public health.
PubMed: 37692291
DOI: 10.1016/j.nmni.2023.101170 -
Pharmaceuticals (Basel, Switzerland) Aug 2023Chagas disease, caused by the parasitic protozoan, is a neglected tropical disease (NTD) of significant incidence in Latin America. Transmission to humans and other... (Review)
Review
Chagas disease, caused by the parasitic protozoan, is a neglected tropical disease (NTD) of significant incidence in Latin America. Transmission to humans and other mammals is mainly via the vector insect from the Reduviidae family, popularly known as the kissing bug. There are other transmission means, such as through congenital transmission, blood transfusions, organ transplantations, and the consumption of contaminated food. For more than 50 years, the disease has been treated with benznidazole and nifurtimox, which are only effective during the acute phase of the disease. In addition to their low efficacy in the chronic phase, they cause many adverse effects and are somewhat selective. The use of nanocarriers has received significant attention due to their ability to encapsulate and release therapeutic agents in a controlled manner. Generally, their diameter ranges from 100 to 300 nanometers. The objective of this scoping review was to perform a search of the literature for the use of nanocarriers as an alternative for improving the treatment of Chagas disease and to suggest future research. Bibliographic searches were carried out in the Web of Science and PubMed scientific databases from January 2012 to May 2023, using the "Chagas disease and and nanoparticles" keywords, seeking to gather the largest number of articles, which were evaluated using the inclusion and exclusion criteria. After analyzing the papers, the results showed that nanocarriers offer physiological stability and safety for the transport and controlled release of drugs. They can increase solubility and selectivity against the parasite. The in vitro assays showed that the trypanocidal activity of the drug was not impaired after encapsulation. In the in vivo assays, parasitemia reduction and high survival and cure rates in animals were obtained during both phases of the disease using lower doses when compared to the standard treatment. The scoping review showed that nanocarriers are a promising alternative for the treatment of Chagas disease.
PubMed: 37631078
DOI: 10.3390/ph16081163 -
Insects Jul 2023The assassin bug genus Stål, 1861 (Hemiptera: Reduviidae: Stenopodainae) has a disjunct distribution in Sub-Saharan Africa and Asia. In the present study, the Asian...
The assassin bug genus Stål, 1861 (Hemiptera: Reduviidae: Stenopodainae) has a disjunct distribution in Sub-Saharan Africa and Asia. In the present study, the Asian species of are revised. Two species are recognized, redescribed, and illustrated, with the following new subjective synonyms and new combination proposed: Stål, 1861 = Distant, 1909, = Distant, 1919, ; (Reuter, 1882) = Distant, 1919, = Livingstone & Ravichandran, 1989, ; (Distant, 1909), (transferred from ) = Hsiao, 1977, Lectotypes for , , and are designated. A key to separate the two Asian species of is provided. The sexual dimorphism, systematic relationships, and distribution of are discussed. is newly recorded from Laos, Pakistan, and Vietnam.
PubMed: 37623389
DOI: 10.3390/insects14080680