Annales de la Société Belge de Médecine Tropicale ; Supplement Vol. 71. 1
266 s. : obr., tab., přeruš.bibl.
Sedentary bird species are suitable model hosts for identifying potential vectors of avian blood parasites. We studied haemosporidian infections in the Tengmalm's Owl (Aegolius funereus) in the Ore Mountains of the Czech Republic using molecular detection methods. Sex of owl nestlings was scored using molecular sexing based on fragment analysis of PCR-amplified CHD1 introns. Observed infection prevalences in nestlings and adult owls were 51 and 86 %, respectively. Five parasite lineages were detected. Most of the infections comprised the Leucocytozoon AEFUN02 and STOCC06 lineages that probably refer to distinct Leucocytozoon species. Other lineages were detected only sporadically. Mixed infections were found in 49 % of samples. The main factor affecting the probability of infection was host age. No effect of individual sex on infection probability was evidenced. The youngest infected nestling was 12 days old. High parasite prevalence in the Tengmalm's Owl nestlings suggests that insect vectors must enter nest boxes to transmit parasites before fledging. Hence, we placed sticky insect traps into modified nest boxes, collected potential insect vectors, and examined them for the presence of haemosporidian parasites using molecular detection. We trapped 201 insects which were determined as biting midges from the Culicoides genus and two black fly species, Simulium (Nevermannia) vernum and Simulium (Eusimulium) angustipes. Six haemosporidian lineages were detected in the potential insect vectors, among which the Leucocytozoon lineage BT2 was common to the Tengmalm's Owl and the trapped insects. However, we have not detected the most frequently encountered Tengmalm's Owl Leucocytozoon lineages AEFUN02 and STOCC06 in insects.
- MeSH
- Ceratopogonidae parasitology MeSH
- Haemosporida genetics isolation & purification MeSH
- Insect Vectors parasitology MeSH
- Bird Diseases epidemiology parasitology transmission MeSH
- Polymerase Chain Reaction MeSH
- Prevalence MeSH
- Protozoan Infections, Animal epidemiology parasitology transmission MeSH
- Sex Factors MeSH
- Simuliidae parasitology MeSH
- Strigiformes parasitology MeSH
- Age Factors MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- Czech Republic MeSH
WHO technical report series ; no. 531
48 s. : il.
- Conspectus
- Veřejné zdraví a hygiena
- NML Fields
- environmentální vědy
- mikrobiologie, lékařská mikrobiologie
BACKGROUND: Leishmania virulence factors responsible for the complicated epidemiology of the various leishmaniases remain mainly unidentified. This study is a characterization of a gene previously identified as upregulated in two of three overlapping datasets containing putative factors important for Leishmania's ability to establish mammalian intracellular infection and to colonize the gut of an insect vector. METHODOLOGY/PRINCIPAL FINDINGS: The investigated gene encodes ATP/GTP binding motif-containing protein related to Leishmania development 1 (ALD1), a cytosolic protein that contains a cryptic ATP/GTP binding P-loop. We compared differentiation, growth rates, and infective abilities of wild-type and ALD1 null mutant cell lines of L. mexicana. Loss of ALD1 results in retarded growth kinetics but not defects in differentiation in axenic culture. Similarly, when mice and the sand fly vector were infected with the ALD1 null mutant, the primary difference in infection and colonization phenotype relative to wild type was an inability to achieve maximal host pathogenicity. While ability of the ALD1 null mutant cells to infect macrophages in vitro was not affected, replication within macrophages was clearly curtailed. CONCLUSIONS/SIGNIFICANCE: L. mexicana ALD1, encoding a protein with no assigned functional domains or motifs, was identified utilizing multiple comparative analyses with the related and often experimentally overlooked monoxenous flagellates. We found that it plays a role in Leishmania infection and colonization in vitro and in vivo. Results suggest that ALD1 functions in L. mexicana's general metabolic network, rather than function in specific aspect of virulence as anticipated from the compared datasets. This result validates our comparative genomics approach for finding relevant factors, yet highlights the importance of quality laboratory-based analysis of genes tagged by these methods.
- MeSH
- Insect Vectors parasitology MeSH
- Leishmania mexicana genetics pathogenicity MeSH
- Leishmaniasis, Cutaneous parasitology MeSH
- Macrophages parasitology MeSH
- Mice, Inbred BALB C MeSH
- Mice MeSH
- GTP-Binding Proteins genetics metabolism MeSH
- Protozoan Proteins genetics metabolism MeSH
- Psychodidae parasitology MeSH
- Virulence MeSH
- Gene Expression Regulation, Developmental MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Sand flies remain the only proven vectors of Leishmania spp. but recent implementation of PCR techniques has led to increasing speculation about "alternative vectors", including biting midges. Here, we summarize that PCR has considerable limits for studing the role of bloodsucking arthropods in the epidemiology of leishmaniasis. The Leishmania life cycle in the sand fly includes a complex series of interactions which are in many cases species-specific, the early phase of the infection is, however, non-specific to sand flies. These facts should be considered in detection of Leishmania in ,"alternative" or "new" vectors to avoid mistaken speculation about their vector competence.
BACKGROUND: Although avian trypanosomes are widespread parasites, the knowledge of their vectors is still incomplete. Despite biting midges (Diptera: Ceratopogonidae) are considered as potential vectors of avian trypanosomes, their role in transmission has not been satisfactorily elucidated. Our aim was to clarify the potential of biting midges to sustain the development of avian trypanosomes by testing their susceptibility to different strains of avian trypanosomes experimentally. Moreover, we screened biting midges for natural infections in the wild. RESULTS: Laboratory-bred biting midges Culicoides nubeculosus were highly susceptible to trypanosomes from the Trypanosoma bennetti and T. avium clades. Infection rates reached 100%, heavy infections developed in 55-87% of blood-fed females. Parasite stages from the insect gut were infective for birds. Moreover, midges could be infected after feeding on a trypanosome-positive bird. Avian trypanosomes can thus complete their cycle in birds and biting midges. Furthermore, we succeeded to find infected blood meal-free biting midges in the wild. CONCLUSIONS: Biting midges are probable vectors of avian trypanosomes belonging to T. bennetti group. Midges are highly susceptible to artificial infections, can be infected after feeding on birds, and T. bennetti-infected biting midges (Culicoides spp.) have been found in nature. Moreover, midges can be used as model hosts producing metacyclic avian trypanosome stages infective for avian hosts.
- MeSH
- Ceratopogonidae anatomy & histology parasitology MeSH
- Gastrointestinal Tract parasitology MeSH
- Insect Vectors parasitology MeSH
- Host Specificity MeSH
- Canaries parasitology MeSH
- Microscopy, Electron, Scanning MeSH
- Bird Diseases parasitology transmission MeSH
- Polymerase Chain Reaction MeSH
- Birds parasitology MeSH
- Trypanosoma classification genetics physiology ultrastructure MeSH
- Trypanosomiasis diagnosis parasitology transmission veterinary MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
130 s. : il. ; 26 cm + 1 příloha
- MeSH
- Insect Vectors MeSH
- Disease Vectors MeSH
- Malaria prevention & control MeSH
- Malaria Vaccines MeSH
- Conspectus
- Patologie. Klinická medicína
- NML Fields
- infekční lékařství
- cestovní a tropická medicína
- NML Publication type
- publikace WHO
Mosquitoes (Diptera: Culicidae) represent a huge threat for millions of humans and animals worldwide, since they act as vectors for important parasites and pathogens, including malaria, filariasis and important arboviruses, such as dengue, West Nile and Zika virus. No vaccines or other specific treatments are available against the arboviruses transmitted by mosquitoes, and avoidance of mosquito bites remains the best strategy. African regions are usually hit most whose inhabitants are poor, and the use of repellent plants is the only efficient protection against vectors they have. Ethnobotanical knowledge of such plants and their use is usually passed on orally from one generation to another. However, it is also important to preserve this information in a written form, as well. Ethnobotanical research projects carried out in the regions of today's Ethiopia, South Africa, Nigeria, Kenya, and Tanzania indicate that the native inhabitants of the African study regions traditionally use 64 plant species, belonging to 30 families. Aromatic plants (i.e., Citrus spp., Eucalyptus spp., Lantana camara, Ocimum spp. and Lippia javanica) the most commonly used in all the study regions. Native people know three major methods of using repellent plants: (i) production of repellent smoke from burning plants, (ii) hanging plants inside the house or sprinkling leaves on the floor, (iii) the use of plant oils, juices from crushed fresh parts of the plants, or various prepared extracts applied on uncovered body parts. Overall, this review covers studies conducted only in a limited part of the African continent, highlighting the importance to undertake further research efforts to preserve the unique knowledge and traditions of the native tribes.
- MeSH
- Culicidae * MeSH
- Ethnobotany MeSH
- Insect Vectors * MeSH
- Mosquito Nets MeSH
- Insect Repellents classification MeSH
- Plant Extracts MeSH
- Health Knowledge, Attitudes, Practice ethnology MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
- Geographicals
- Africa MeSH
Leishmania species, members of the kinetoplastid parasites, cause leishmaniasis, a neglected tropical disease, in millions of people worldwide. Leishmania has a complex life cycle with multiple developmental forms, as it cycles between a sand fly vector and a mammalian host; understanding their life cycle is critical to understanding disease spread. One of the key life cycle stages is the haptomonad form, which attaches to insect tissues through its flagellum. This adhesion, conserved across kinetoplastid parasites, is implicated in having an important function within their life cycles and hence in disease transmission. Here, we discover the kinetoplastid-insect adhesion proteins (KIAPs), which localise in the attached Leishmania flagellum. Deletion of these KIAPs impairs cell adhesion in vitro and prevents Leishmania from colonising the stomodeal valve in the sand fly, without affecting cell growth. Additionally, loss of parasite adhesion in the sand fly results in reduced physiological changes to the fly, with no observable damage of the stomodeal valve and reduced midgut swelling. These results provide important insights into a comprehensive understanding of the Leishmania life cycle, which will be critical for developing transmission-blocking strategies.
- MeSH
- Cell Adhesion MeSH
- Flagella * metabolism MeSH
- Insect Vectors parasitology MeSH
- Insect Proteins metabolism genetics MeSH
- Host-Parasite Interactions MeSH
- Leishmania * physiology genetics metabolism MeSH
- Leishmaniasis parasitology transmission MeSH
- Protozoan Proteins metabolism genetics MeSH
- Psychodidae * parasitology MeSH
- Life Cycle Stages MeSH
- Animals MeSH
- Check Tag
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Many plant viruses are vectored by insects in a persistent circulative manner. The insect gut and salivary gland are important barriers limiting virus spread, but the mechanisms by which viruses are able to cross the gut escape barriers of the insect remain largely unknown. Wheat dwarf virus (WDV), transmitted by Psammotettix alienus in a persistent, circulative, and nonpropagative manner, causes the most economically important virus disease in wheat. In this study, ADP ribosylation factor 1 (ARF1) was found to interact with the coat protein of WDV in a yeast two-hybrid, pull-down assay and to colocalise with virions in the gut and salivary glands of P. alienus. When transcription of ARF1 was suppressed by RNA interference, the WDV titre decreased in the haemolymph and salivary glands, and transmission efficiency decreased, but titre in the gut did not differ from that of the control. These data suggest that ARF1 of P. alienus binds to the WDV virion and helps virus spread from gut to haemolymph. Our study provides direct experimental evidence that WDV can use the existing membrane trafficking mechanism to aid its spread within the insect vector. This first analysis of the molecular interaction between WDV and its vector P. alienus contributes to understanding the mechanisms involved in circulative transmission of the virus by the leafhopper vector.
- MeSH
- ADP-Ribosylation Factor 1 genetics metabolism MeSH
- Cell Line MeSH
- Geminiviridae pathogenicity MeSH
- Hemiptera genetics metabolism virology MeSH
- Insect Vectors genetics MeSH
- Plant Diseases virology MeSH
- RNA Interference MeSH
- Salivary Glands metabolism virology MeSH
- Intestines virology MeSH
- Two-Hybrid System Techniques MeSH
- Virion metabolism MeSH
- Capsid Proteins metabolism MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
