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Parasites & Vectors May 2024Volatile organic compounds (VOCs) are chemicals emitted as products of cell metabolism, which reflects the physiological and pathological conditions of any living... (Review)
Review
Volatile organic compounds (VOCs) are chemicals emitted as products of cell metabolism, which reflects the physiological and pathological conditions of any living organisms. These compounds play a key role as olfactory cues for arthropod vectors such as mosquitoes, sand flies, and ticks, which act in the transmission of pathogens to many animal species, including humans. Some VOCs may influence arthropod behaviour, e.g., host preference and oviposition site selection for gravid females. Furthermore, deadly vector-borne pathogens such as Plasmodium falciparum and Leishmania infantum are suggested to manipulate the VOCs profile of the host to make them more attractive to mosquitoes and sand fly vectors, respectively. Under the above circumstances, studies on these compounds have demonstrated their potential usefulness for investigating the behavioural response of mosquitoes, sand flies, and ticks toward their vertebrate hosts, as well as potential tools for diagnosis of vector-borne diseases (VBDs). Herein, we provide an account for scientific data available on VOCs to study the host seeking behaviour of arthropod vectors, and their usefulness as attractants, repellents, or tools for an early diagnosis of VBDs.
Topics: Animals; Volatile Organic Compounds; Psychodidae; Ticks; Humans; Culicidae; Behavior, Animal; Vector Borne Diseases; Female; Mosquito Vectors; Plasmodium falciparum
PubMed: 38755646
DOI: 10.1186/s13071-024-06299-1 -
Anais Da Academia Brasileira de Ciencias 2024Aiming to compare and update the sand fly fauna of Portão de Pedra site, Sumidouro District, Rio de Janeiro State, Brazil, and considering the environmental changes...
Aiming to compare and update the sand fly fauna of Portão de Pedra site, Sumidouro District, Rio de Janeiro State, Brazil, and considering the environmental changes occurred, the biology and ecology of the local sandfly species were examined five years later as a complementary study carried. Captures were made in the cave, surroundings of cave and forest of the region, from 6 p.m. to 6 a.m. Among the 2323 sandflies of eigth species of the Lutzomyia were captured: L. gasparviannai, L. edwardsi, L. tupynambai, L. hirsuta, L. whitmani, L. migonei, L. intermedia, Lutzomyia. sp and one species of the Brumptomyia Kind: B. brumpti. In 2009 and 2010 were collected 1756 samples from ten species of the former genus and two of the second. L. gasparviannai was predominant, in the three collection sites, in both periods. Five species implicated as vectors of Leishmania: L. intermedia, L. whitmani, L. migonei, L. hirsuta and L. davisi have been collected in the area. Poisson regression and ANOVA were used to perform statistical analysis of species most relevant. The record of L. intermedia and a case of American tegumentary leishmaniasis are relevant to the public health of municipality and of state of Rio de Janeiro.
Topics: Animals; Psychodidae; Brazil; Insect Vectors; Population Density; Female; Male; Seasons; Ecosystem
PubMed: 38747792
DOI: 10.1590/0001-3765202420230872 -
The Journal of Infectious Diseases Jun 2024In an area endemic with Indian visceral leishmaniasis (VL), we performed direct xenodiagnosis to evaluate the transmission of Leishmania donovani from patients with...
In an area endemic with Indian visceral leishmaniasis (VL), we performed direct xenodiagnosis to evaluate the transmission of Leishmania donovani from patients with VL-human immunodeficiency virus (HIV) coinfection to the vector sandflies, Phlebotomus argentipes. Fourteen patients with confirmed VL-HIV coinfection, with a median parasitemia of 42 205 parasite genome/mL of blood, were exposed to 732 laboratory-reared pathogen-free female P argentipes sandflies on their lower arms and legs. Microscopy revealed that 16.66% (122/732) of blood-fed flies were xenodiagnosis positive. Notably, 93% (13/14) of the VL-HIV group infected the flies, as confirmed by quantitative polymerase chain reaction and/or microscopy, and were 3 times more infectious than those who had VL without HIV.
Topics: Leishmaniasis, Visceral; Animals; Humans; India; HIV Infections; Female; Adult; Coinfection; Leishmania donovani; Male; Phlebotomus; Endemic Diseases; Middle Aged; Young Adult; Xenodiagnosis; Insect Vectors; Adolescent
PubMed: 38713583
DOI: 10.1093/infdis/jiae156 -
Acta Tropica Jul 2024Lutzomyia longipalpis is the primary vector of Leishmania infantum in the Americas and a permissive vector for Leishmania amazonensis. Previous studies showed that...
Attractiveness of Golden Hamster infected with Leishmania amazonensis (Kinetoplastida: Trypanosomatidae) to laboratory-reared Lutzomyia longipalpis (Diptera: Psychodidae).
Lutzomyia longipalpis is the primary vector of Leishmania infantum in the Americas and a permissive vector for Leishmania amazonensis. Previous studies showed that Leishmania infantum-infected hosts can release different volatile organic compounds (VOCs) compared with uninfected hosts, presenting a higher attractiveness to vectors. In this study, we aimed to evaluate a possible effect of L. amazonensis infection of golden hamsters in three parameters: attractiveness to Lu. longipalpis females; blood volume ingested by sand fly females; and VOCs released by the animals.. Attractiveness was measured indirectly by the number of Lu. longipalpis females that blood fed in each L. amazonensis-infected and uninfected animal. For VOCs extraction, solid phase micro extraction fibers were used, which were analyzed by gas chromatography-mass spectrometry. Behavioral trials did not show any effect of L. amazonensis infection on the attraction of sand flies nor difference on blood meal rates of Lu. longipalpis fed in both goups of hamsters. Additionally, there was no difference between the VOCs profiles of L. amazonensis-infected or uninfected hamsters.
Topics: Animals; Psychodidae; Volatile Organic Compounds; Female; Mesocricetus; Cricetinae; Insect Vectors; Leishmania mexicana; Feeding Behavior; Gas Chromatography-Mass Spectrometry; Leishmania
PubMed: 38710262
DOI: 10.1016/j.actatropica.2024.107238 -
Journal of Medical Entomology May 2024Understanding the distribution patterns of medically significant sandflies is crucial for effective vector and disease control planning. This study focused on...
The abundance and distribution of sandflies (with emphasis on Phlebotomus pedifer) (Diptera: Psychodidae) along the altitudinal gradient in Kindo Didaye district, Wolaita Zone, South Ethiopia.
Understanding the distribution patterns of medically significant sandflies is crucial for effective vector and disease control planning. This study focused on investigating the abundance and distribution of phlebotomine sandflies, specifically emphasizing Phlebotomus pedifer (Diptera: Psychodidae), the vector of Leishmania aethiopica responsible for cutaneous leishmaniasis in the highlands of southern Ethiopia. The study employed CDC light traps and sticky paper traps in various habitats, including human houses, farm fields, and rock cliffs, with and without the presence of hyraxes. The study was conducted along an altitudinal gradient in Kindo Didaye district, Wolaita Zone. A total of 7,994 sandflies belonging to 2 genera, Phlebotomus (26.1%) and Sergentomyia (73.9%), were collected. In the genus Phlebotomus, P. pedifer (74.1%) was the most abundant, followed by P. alexandri (18.05%) and P. gibiensis (7.85%). Altitude showed a strong positive association with the density and distribution of P. pedifer and a negative association with those of P. alexandri, P. gibiensis, and Sergentomyia spp. Furthermore, the study revealed distinct habitat preferences, with P. pedifer showing the highest mean density in hyrax dwellings, followed by human houses, and the lowest in farm fields. These findings provide valuable insights for planning targeted control measures against P. pedifer in both indoor and outdoor environments, particularly in the highland and midland areas of the study region.
PubMed: 38697924
DOI: 10.1093/jme/tjae049 -
Microorganisms Apr 2024The present work assessed the experimental susceptibility of and to () and (.) . A () - combination was used as a susceptible control. Wild-caught and...
The present work assessed the experimental susceptibility of and to () and (.) . A () - combination was used as a susceptible control. Wild-caught and laboratory-bred were membrane-fed on blood with a 5 × 10/mL log-phase promastigote culture suspension and dissected on days 2 and 8 post-blood meal (pbm) for analysis focused on the assessment of parasitoses, as well as placement and promastigote morphotyping. Survival curves were constructed. In all combinations, promastigotes were observed on day 8 pbm. For both species, in , the presence of parasites was observed up to the stomodeal valve, while in , the presence of parasites was observed up to the cardia. There were no significant differences in parasitosis between () and () in either or . Six morphological promastigote forms were distinguished in Giemsa-stained gut smears. The survival curves of all combinations decreased and were affected differently by several -parasite combinations, as well with -uninfected blood. These findings stress as experimentally susceptible to spp. and suggest the putative susceptibility of to () and () .
PubMed: 38674753
DOI: 10.3390/microorganisms12040809 -
Journal of Vector Borne Diseases Jan 2024In Brazil, one of the visceral leishmaniasis control measures in urban environments is the elimination of Lutzomyia longipalpis, which occurs through the application of...
BACKGROUND OBJECTIVES
In Brazil, one of the visceral leishmaniasis control measures in urban environments is the elimination of Lutzomyia longipalpis, which occurs through the application of pyrethroid insecticides with residual action in homes and outbuildings. Due to the loss of sensitivity of this vector to these insecticides, the search for more efficient insecticide compounds against L. longipalpis has been intensified. The objective of this work was to evaluate the toxicity of Trixis vauthieri essential oil on adult sandflies of the species L. longipalpis, and identify the phytochemical composition of these essential oils.
METHODS
Essential oils from leaves collected from T. vauthieri at different times were obtained at concentrations of 5, 10 and 20 mg/mL. Twenty sandflies were exposed to the essential oils and the mortality was evaluated after 1, 2, 4, 16, 24, 48 and 72 h. The chemical constituents of the essential oil were also identified.
RESULTS
The essential oils of T. vauthieri at a concentration of 20 mg/mL were the most toxic to sandflies, reaching a mortality rate of 98.33% and 95%, respectively, after 72 h of exposure. The analysis of chemical constituents revealed the presence of triterpenes and/or steroids, tannins, flavonoids, alkaloids, saponins and coumarins.
INTERPRETATION CONCLUSION
The results obtained suggest that T. vauthieri essential oil is fairly promising as an insecticidal potential against L. longipalpis. A more detailed analysis of the oil's phytochemical composition is necessary to identify active and pure compounds that can be used in vector control of visceral leishmaniasis.
Topics: Animals; Psychodidae; Oils, Volatile; Insecticides; Leishmaniasis, Visceral; Brazil; Insect Vectors; Plant Leaves; Female; Plant Oils
PubMed: 38648417
DOI: 10.4103/0972-9062.383642 -
Frontiers in Immunology 2024Cutaneous leishmaniasis is a neglected vector-borne parasitic disease prevalent in 92 countries with approximately one million new infections annually. Interactions...
INTRODUCTION
Cutaneous leishmaniasis is a neglected vector-borne parasitic disease prevalent in 92 countries with approximately one million new infections annually. Interactions between vector saliva and the human host alter the response to infection and outcome of disease.
METHODS
To characterize the human immunological responses developed against saliva of , a vector, we repeatedly exposed the arms of 14 healthy U.S volunteers to uninfected bites. Blood was collected a week after each exposure and used to assess total IgG antibodies against the proteins of salivary gland homogenate (SGH) and the levels of IFN-gamma and IL-10 from peripheral blood mononuclear cells (PBMCs) stimulated with SGH or recombinant sand fly proteins. We analyzed skin punch biopsies of the human volunteer arms from the insect bite site and control skin site after multiple exposures (four volunteers) using immunohistochemical staining.
RESULTS
A variety of immediate insect bite skin reactions were observed. Late skin reactions to insect bites were characterized by macular hyperpigmentation and/or erythematous papules. Hematoxylin and eosin staining showed moderate mononuclear skin infiltrate with eosinophils in those challenged recently (within 2 months), eosinophils were not seen in biopsies with recall challenge (6 month post bites). An increase in plasma antigen-specific IgG responses to SGH was observed over time. Western Blot results showed strong plasma reactivity to five salivary proteins. Importantly, volunteers developed a cellular immunity characterized by the secretion of IFN-gamma upon PBMC stimulation with SGH and recombinant antigens.
DISCUSSION
Our results demonstrate that humans mounted a local and systemic immune response against salivary proteins. Specifically, PduM02/SP15-like and PduM73/adenosine deaminase recombinant salivary proteins triggered a Th1 type immune response that might be considered in future development of a potential vaccine.
Topics: Animals; Humans; Phlebotomus; Leukocytes, Mononuclear; Insect Bites and Stings; Immunity, Cellular; Antigens; Immunoglobulin G; Salivary Proteins and Peptides
PubMed: 38633260
DOI: 10.3389/fimmu.2024.1335307 -
PloS One 2024In Nepal, visceral leishmaniasis (VL) has been targeted for elimination as a public health problem by 2026. Recently, increasing numbers of VL cases have been reported...
In Nepal, visceral leishmaniasis (VL) has been targeted for elimination as a public health problem by 2026. Recently, increasing numbers of VL cases have been reported from districts of doubtful endemicity including hills and mountains, threatening the ongoing VL elimination program in Nepal. We conducted a multi-disciplinary, descriptive cross-sectional survey to assess the local transmission of Leishmania donovani in seven such districts situated at altitudes of up to 1,764 meters in western Nepal from March to December 2019. House-to-house surveys were performed for socio-demographic data and data on past and current VL cases. Venous blood was collected from all consenting individuals aged ≥2 years and tested with the rK39 RDT. Blood samples were also tested with direct agglutination test, and a titer of ≥1:1600 was taken as a marker of infection. A Leishmania donovani species-specific PCR (SSU-rDNA) was performed for parasite species confirmation. We also captured sand flies using CDC light traps and mouth aspirators. The house-to-house surveys documented 28 past and six new VL cases of which 82% (28/34) were without travel exposure. Overall, 4.1% (54/1320) of healthy participants tested positive for L. donovani on at least one serological or molecular test. Among asymptomatic individuals, 17% (9/54) were household contacts of past VL cases, compared to 0.5% (6/1266) among non-infected individuals. Phlebotomus argentipes, the vector of L. donovani, was found in all districts except in Bajura. L. donovani was confirmed in two asymptomatic individuals and one pool of sand flies of Phlebotomus (Adlerius) sp. We found epidemiological and entomological evidence for local transmission of L. donovani in areas previously considered as non-endemic for VL. The national VL elimination program should revise the endemicity status of these districts and extend surveillance and control activities to curb further transmission of the disease.
Topics: Animals; Humans; Leishmaniasis, Visceral; Nepal; Cross-Sectional Studies; Leishmania donovani; Phlebotomus; Psychodidae
PubMed: 38630746
DOI: 10.1371/journal.pone.0289578 -
The American Journal of Tropical... Jun 2024Leishmaniasis is considered one of the neglected tropical diseases in the world. Although Bhutan is a member of the visceral leishmaniasis elimination consortium in...
Leishmaniasis is considered one of the neglected tropical diseases in the world. Although Bhutan is a member of the visceral leishmaniasis elimination consortium in South Asia, not much attention has been accorded to the disease because of its low incidence. The vector that transmits Leishmania remains poorly understood. In this backdrop, sand-fly surveys were regularly conducted at multiple sites where leishmaniasis cases have been reported in Bhutan. Collections were made using CDC light traps and cattle-baited net traps in 15 villages from February 2019 to May 2022. Six species of Phlebotomus and four species of Sergentomyia were identified from these sites that included two Phlebotomus and three Sergentomyia species discovered for the first time in Bhutan. Sand-fly density varied significantly from village to village, and it showed strong seasonality with peak numbers collected from June to October and almost zero from December to February. Overall, sand-fly density was highest in the basements of the houses and were higher outdoors than indoors. Cattle-baited net traps collected few sand flies during the surveillance period. This work constituted the first systematic sand-fly population surveillance conducted in Bhutan and will provide a baseline for future vector ecology and Leishmania epidemiological studies.
Topics: Animals; Bhutan; Seasons; Phlebotomus; Insect Vectors; Psychodidae; Leishmaniasis; Cattle; Humans; Female; Animal Distribution; Leishmaniasis, Visceral
PubMed: 38593793
DOI: 10.4269/ajtmh.23-0125