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Zootaxa Aug 2023Molecular research based on gene sequence analysis and performed for decades, in general, supported morphology-based groupings of the species within the family...
Molecular research based on gene sequence analysis and performed for decades, in general, supported morphology-based groupings of the species within the family Culicidae, but phylogenetic relationships between some genera and tribes remained uncertain for a long time. Interspecific differences in catalase, an antioxidant enzyme important for maintaining prolonged lifespan and reproduction, have not been studied extensively by estimating enzymatic activity levels. Here, catalase enzymatic activity was assayed in extracts of male mosquitoes belonging to 10 species of the subfamily Culicinae, including species from tribes of disputable phylogeny. Three species of Chaoboridae (nearest outgroup taxon) and mosquitoes from the subfamily Anophelinae (one species complex) were also added to the study. At least in Culicinae, immature adult males (less than one day after emergence) have distinctly elevated specific activity of catalase; therefore, only mature males of all species were used for the comparative study. As a result, significant differences in catalase activity were revealed between tribes, genera and particular species. Among culicids, the genera Coquillettidia and Culiseta were found to include the species with the highest and relatively high catalase activity, which is consistent with the affinity of the tribes Mansoniini and Culisetini to each other. Within Ochlerotatus, extremely low catalase activity in Oc. hexodontus suggests the more distant position of this species from Oc. cantans (Meigen) and Oc. communis (de Geer) than the positions of the latter two species from each other. Additional study of catalase activity in overwintering females of the genus Culex revealed significantly higher enzyme activity in Cx. torrentium in comparison with Cx. pipiens, which supports their quite distant positions from each other within the genus. Considering the distribution of catalase activity within the tree obtained, the preliminary outcome is that Culiseta retains the elevated level of catalase activity that was lost during the early separation of Anopheles and subsequent separation of Culex and Aedes/Ochlerotatus after Anopheles from their common branch with Culiseta/Coquillettidia. Overall, the use of taxonomic distribution of catalase activity levels appears to be effective for resolving disputed events of mosquito phylogeny.
Topics: Male; Female; Animals; Culicidae; Phylogeny; Catalase; Culex; Anopheles; Ochlerotatus
PubMed: 38221060
DOI: 10.11646/zootaxa.5339.2.3 -
Trends in Parasitology Feb 2024Malaria is a life-threatening tropical disease caused by parasites of the genus Plasmodium, of which Plasmodium falciparum is the most lethal. Malaria parasites have a... (Review)
Review
Malaria is a life-threatening tropical disease caused by parasites of the genus Plasmodium, of which Plasmodium falciparum is the most lethal. Malaria parasites have a complex life cycle, with stages occurring in both the Anopheles mosquito vector and human host. Ring stages are the youngest form of the parasite in the intraerythrocytic developmental cycle and are associated with evasion of spleen clearance, temporary growth arrest (TGA), and drug resistance. This formidable ability to survive and develop into mature, sexual, or growth-arrested forms demonstrates the inherent population heterogeneity. Here we highlight the role of the ring stage as a crossroads in parasite development and as a reservoir of surviving cells in the human host via TGA survival mechanisms.
Topics: Animals; Humans; Antimalarials; Drug Resistance; Life Cycle Stages; Malaria; Malaria, Falciparum; Plasmodium falciparum
PubMed: 38104024
DOI: 10.1016/j.pt.2023.11.007 -
Medecine Tropicale Et Sante... Sep 2023Malaria is a major health problem in Benin where it is the main cause of morbidity and mortality, particularly among children under 5 and pregnant women. Although the...
BACKGROUND & RATIONALE
Malaria is a major health problem in Benin where it is the main cause of morbidity and mortality, particularly among children under 5 and pregnant women. Although the vast majority of malaria cases occurs in rural and agricultural areas and are often associated with development projects, very few interventions target the agro-ecosystem. In Benin, irrigated rice growing is expanding to meet the increasing demand of the population. However, continuous flooding and tillage systems induce the development and proliferation of malaria and other diseases vectors. Intermittent flooding of rice plots and minimal tillage can reduce significantly the proliferation of mosquitoes including in rice fields. However, the dissemination and implementation of these agricultural practices require community-wide action for greater effectiveness. As part of strengthening the capacity of farming communities in the fight against malaria vectors, the "Farmer Field School" appears to be an innovative approach. This learning by doing method promotes interactions between groups of producers to disseminate proven technologies. This study aims to disseminate among rice producers the agricultural practices of intermittent flooding and minimal tillage, likely to reduce the proliferation of malaria vectors in the rice fields.
MATERIALS & METHODS
This study was carried out in the rice-growing perimeter of Malanville, Benin (11° 52' 5" North, 3° 22' 59" East) which covers an area of 516 hectares. Farmer Field Schools were set up after a basic survey at producer level. This survey was carried out through in-depth interview, focus group discussions and direct field observation with producers. Focus groups discussions and interviews made it possible to understand the perception of rice farmers on the link between rice production and the transmission of malaria. In order to disseminate new agricultural practices such as intermittent flooding and minimal tillage among producers, twelve plots have been set up. Farmer Field Schools were monitored weekly with rice producers accompanied by a facilitator and a medical entomologist (learning facilitator or moderator) helping the farmers with the collection and identification of mosquito larvae. According to the different stages of rice development (transplanting, tillering, maturation), the mosquito larvae were collected in the test and control plots from 10 a.m. to 2 p.m. by the dipping method. Then the water in the test compartments (intermittent flooding) was emptied. A cycle of 7 days of flooding and 2 days of drying was carried out for intermittent flooding. Mosquito larvae were identified morphologically using the identification key and genus larvae were isolated in plastic cups. The impacts of intermittent flooding and minimum tillage in reducing breeding sites and larval densities were established by determining and comparing the larval densities of mosquitoes and of between the test and control plots.
RESULTS
Direct observations in the field allowed to identify three tillage systems, which include the use of tiller (28%), plow (66%) and hoe (6%) on the rice field. Continuous flooding was the only irrigation system used by farmers. The water used for irrigation comes either from boreholes installed individually or from the Niger River. The volume of water used varies with the seasons, the size of the farms and the variety of rice grown. Farmers observe that the nuisance of mosquitoes increases during the rice production period with an outbreak of malaria cases, especially among children, which leads to crowds in health centers. The preventive measures against malaria among farmers are the use of impregnated mosquito nets distributed free of charge by the national program against malaria, and of insecticide bombs or spirals. Considering the development stages of the rice, the larval densities varied according to the treatments. Overall, minimal tillage applied to intermittent flooding significantly reduced the density of mosquito larvae of all species. The reduction rates were 10.5, 5.4 and 2.5 during transplanting, tillering and maturation, respectively. Considering only the larvae, minimal tillage applied to intermittent flooding reduced their density by 16, 5.5 and 4 respectively during transplanting, tillering and maturation.
DISCUSSION/CONCLUSION
The rice-growing area of Malanville has many favorable conditions for rice production, including the presence of water supply sources such as the Niger River located near the rice field and numerous boreholes. The availability of water pockets for mosquito breeding during irrigation appeared to contribute to the extension of malaria transmission. The present study showed that the intermittent flooding coupled with minimal tillage could reduce the proliferation of malaria vectors. The results suggested that with technical support to farmers through the "Farmer Field School", the malaria incidence could be reduced in the farming community.
Topics: Pregnancy; Animals; Child; Humans; Female; Malaria; Ecosystem; Anopheles; Oryza; Farmers; Benin; Mosquito Vectors; Larva; Schools; Water
PubMed: 38094479
DOI: 10.48327/mtsi.v3i3.2023.281 -
Heliyon Dec 2023In the department of Córdoba, 21 widely distributed species have been described, of which , , , and are the most abundant species, and the last three play a vectorial...
In the department of Córdoba, 21 widely distributed species have been described, of which , , , and are the most abundant species, and the last three play a vectorial role in Malaria transmission in Colombia. A correct taxonomic identification of malaria insect vectors is of vital importance for the development of effective vector control strategies. However, the identification of individuals from the genus presents difficulties due to the loss of relevant morphological characters during the transport and preservation of the collected specimens. In addition to the interspecific variations, and the intraspecific similarities of the species belonging to the subgenus since itpresents species complexes and cryptic species that difficults identification based only in morphological characteristics. The objective of this study was to characterize the barcode fragment of the COI gene and its genetic diversity for the identification of . and . in areas of high malaria transmission from the department of Córdoba. 67 individuals belonging to the species cytotype and 22 were identified, and additionally, 9 haplotypes were obtained for and 14 for distributed in the study areas. The values obtained in the and estimators indicate a low or null genetic differentiation and a high gene flow between most of the studied populations because they share the most frequent haplotypes of these two species. The maximum likelihood trees for these species showed that the specimens from Córdoba belong to the same mitochondrial lineage as those previously reported from Antioquia, Choco, and Norte de Santander.
PubMed: 38076053
DOI: 10.1016/j.heliyon.2023.e23006 -
Transfusion Jan 2024Malaria is caused by protozoa of the genus Plasmodium and transmitted by Anopheles mosquitos. In the US, blood donors are assessed for malaria risk, including donor...
BACKGROUND
Malaria is caused by protozoa of the genus Plasmodium and transmitted by Anopheles mosquitos. In the US, blood donors are assessed for malaria risk, including donor travel or previous residence in endemic areas and history of malaria by questionnaire and deferred for three months or three years, respectively.
METHODS
The Procleix Plasmodium Assay is a qualitative nucleic acid test based on transcription-mediated amplification (TMA) for the detection of 18S ribosomal RNA of P. falciparum, P. ovale, P. vivax, P. malariae, and P. knowlesi for use on the Procleix Panther system. Analytical sensitivity was evaluated with in vitro transcripts and infected red blood cells. For clinical specificity, 12,800 individual donations and 283 pools of 16 samples from routine US donors were screened. Malaria risk was evaluated by testing 862 donors deferred for 3 years. Reactive results were confirmed with in-house real-time TMA assay and serology.
RESULTS
Assay sensitivity was 8.47-11.89 RNA copies/mL and 2.10-6.82 infected red cells/mL. Specificity was 99.99% in 12,800 individual donations and 100% in 283 pools of 16. Of 862 tested deferred donor samples, one donor (0.12%) confirmed positive individually and in pools; he remained confirmed positive for 13 months. The infected donor was a prior resident of a malaria-endemic area in West Africa.
CONCLUSIONS
The Procleix Plasmodium Assay showed high sensitivity and specificity and detected Plasmodium RNA in an asymptomatic presenting donor. This assay may prove helpful as a screening test versus the use of risk questions to reduce the number of donors deferred for malaria risk.
Topics: Animals; Humans; Male; Blood Transfusion; Malaria; Malaria, Falciparum; Plasmodium; RNA
PubMed: 38018462
DOI: 10.1111/trf.17612 -
Parasites & Vectors Nov 2023Adult mosquitoes of the genus Anopheles are important vectors of Plasmodium parasites, causative agents of malaria. The aim of this review was to synthesize the overall... (Review)
Review
BACKGROUND
Adult mosquitoes of the genus Anopheles are important vectors of Plasmodium parasites, causative agents of malaria. The aim of this review was to synthesize the overall and species-specific proportion of Anopheles species infected with sporozoites and their geographical distribution in the last 2 decades (2001-2021).
METHODS
A comprehensive search was conducted using databases (PubMed, Google Scholar, Science Direct, Scopus, African Journals OnLine) and manual Google search between January 1 and February 15, 2022. Original articles describing work conducted in Ethiopia, published in English and reporting infection status, were included in the review. All the required data were extracted using a standardized data extraction form, imported to SPSS-24, and analyzed accordingly. The quality of each original study was assessed using a quality assessment tool adapted from the Joanna Briggs Institute critical appraisal checklist. This study was registered on PROSPERO (International Prospective Register of Systematic Reviews; registration no. CRD42022299078).
RESULTS
A search for published articles produced a total of 3086 articles, of which 34 met the inclusion criteria. Data on mosquito surveillance revealed that a total of 129,410 anophelines comprising 25 species were captured, of which 48,365 comprising 21 species were tested for sporozoites. Anopheles arabiensis was the dominant species followed by An. pharoensis and An. coustani complex. The overall proportion infected with sporozoites over 21 years was 0.87%. Individual proportions included Anopheles arabiensis (1.09), An. pharoensis (0.79), An. coustani complex (0.13), An. funestus (2.71), An. demeilloni (0.31), An. stephensi (0.70), and An. cinereus (0.73). Plasmodium falciparum sporozoites accounted 79.2% of Plasmodium species. Mixed infection of Plasmodium vivax and P. falciparum was only reported from one An. arabiensis sample.
CONCLUSIONS
Anopheles arebiensis was the dominant malaria vector over the years, with the highest sporozoite infection proportion of 2.85% and an average of 0.90% over the years. Other species contributing to malaria transmission in the area were An. pharoensis, An. coustani complex, An. funestus, An. stephensi, and An. coustani. The emergence of new vector species, in particular An. stephensi, is particularly concerning and should be investigated further.
Topics: Animals; Anopheles; Malaria; Sporozoites; Ethiopia; Mosquito Vectors; Systematic Reviews as Topic; Malaria, Falciparum; Plasmodium falciparum; Plasmodium
PubMed: 38008761
DOI: 10.1186/s13071-023-06054-y -
Virus Research Jan 2024Surveillance of mosquito vectors is critical for early detection, prevention and control of vector borne diseases. In this study we used advanced molecular tools, such...
Surveillance of mosquito vectors is critical for early detection, prevention and control of vector borne diseases. In this study we used advanced molecular tools, such as DNA barcoding in combination with novel sequencing technologies to discover new and already known viruses in genetically identified mosquito species. Mosquitoes were captured using BG sentinel traps in Western Kenya during May and July 2019, and homogenized individually before pooled into groups of ten mosquitoes. The pools and individual samples were then used for molecular analysis and to infect cell cultures. Of a total of fifty-four (54) 10-pools, thirteen (13) showed cytopathic effect (CPE) on VeroB4 cells, eighteen (18) showed CPE on C6/36 cells. Eight (8) 10-pools out of the 31 CPE positive pools showed CPE on both VeroB4 and C6/36 cells. When using reverse transcriptase polymerase chain reaction (RT-PCR), Sanger sequencing and Twist Comprehensive Viral Research Panel (CVRP) (Twist Biosciences), all pools were found negative by RT-PCR when using genus specific primers targeting alphaviruses, orthobunyaviruses and virus specific primers towards o'nyong-nyong virus, chikungunya virus and Sindbis virus (previously reported to circulate in the region). Interestingly, five pools were RT-PCR positive for flavivirus. Two of the RT-PCR positive pools showed CPE on both VeroB4 and C6/36 cells, two pools showed CPE on C6/36 cells alone and one pool on VeroB4 cells only. Fifty individual mosquito homogenates from the five RT-PCR positive 10-pools were analyzed further for flavivirus RNA. Of these, 19 out of the 50 individual mosquito homogenates indicated the presence of flavivirus RNA. Barcoding of the flavivirus positive mosquitoes revealed the mosquito species as Aedes aegypti (1), Mansonia uniformis (6), Anopheles spp (3), Culex pipiens (5), Culex spp (1), Coquilletidia metallica (2) and Culex quinquefasciatus (1). Of the 19 flavivirus positive individual mosquitoes, five (5) virus positive homogenates were sequenced. Genome sequences of two viruses were completed. One was identified as the single-stranded RNA Culex flavivirus and the other as the double-stranded RNA Hubei chryso-like virus 1. Both viruses were found in the same Anopheles spp. homogenate extracted from a sample that showed CPE on both VeroB4 and C6/36 cells. The detection of both viruses in a single mosquito homogenate indicated coinfection. Phylogenetic analyses suggested that the Culex flavivirus sequence detected was closely related to a Culex flavivirus isolated from Uganda in 2008. All four Hubei chryso-like virus 1 segments clusters closely to Hubei chryso-like virus 1 strains isolated in Australia, China and USA. Two novel strains of insect-specific viruses in Anopheles mosquitoes were detected and characterized.
Topics: Animals; Culex; Anopheles; Flavivirus; Phylogeny; Kenya; Insect Viruses; RNA
PubMed: 37944758
DOI: 10.1016/j.virusres.2023.199266 -
Tropical Biomedicine Sep 2023Malaria, caused by the unicellular Apicomplexan protozoa of the genus Plasmodium, is an infectious disease transmitted via female Anopheles mosquitoes. The sexual stage...
Malaria, caused by the unicellular Apicomplexan protozoa of the genus Plasmodium, is an infectious disease transmitted via female Anopheles mosquitoes. The sexual stage (gametocytes) of malaria parasites is the key to the transmission of parasites from vertebrate hosts to mosquitoes, representing critical bottleneck of the parasite life cycle. This study has established a systematic computational pipeline to achieve the genome-wide in silico analysis and find 708 novels potentially indispensable genes for gametocyte development, consisting of 644 protein coding genes, 56 ncRNA genes and 8 pseudogenes, with a total of 191 genes in the transmembrane, 29 protein coding genes to be exported proteins, and 58 genes in apicoplast regions. Furthermore, Gene Ontology analysis showed that the largest cluster was cellular processes with nucleus and cytosol highest, followed by molecular function with binding and oxidoreductase activities abundant. Meanwhile, when a text searched, using PlasmoDB, there were 300 genes with annotations of "putative", and 196 genes with annotations of "unknown function". These data would be helpful to provide potential targets for effective malaria transmission-blocking strategies.
Topics: Animals; Female; Plasmodium falciparum; Malaria, Falciparum; Malaria; Plasmodium; Anopheles
PubMed: 37897169
DOI: 10.47665/tb.40.3.012 -
Microorganisms Sep 2023Here, the main goal is to assess natural infections of spp. in anophelines in a forest reserve from the same region where we previously found a surprisingly high rate...
Here, the main goal is to assess natural infections of spp. in anophelines in a forest reserve from the same region where we previously found a surprisingly high rate (5.2%) of plasmodia infections ( = 25) in mosquitoes ( = 480) on the slopes of Serra do Mar, Atlantic Forest, Brazil. The mosquito collection sampling was carried out at the Legado das Águas Forest Reserve using CDC light traps and Shannon traps at night (5-10 pm) in 3-day collections in November 2021 and March, April, May, and November 2022. The captured specimens were morphologically identified at the species level and had their genomic DNA extracted in pools of up to 10 mosquitoes/pool. Each pool was tested using qPCR and nested PCR plus sequencing. A total of 5301 mosquitoes, mostly belonging to the genus (99.7%), were sampled and sorted into 773 pools. Eight pools positive for spp. were identified: four for spp., one for or , one for or , and two for the -like parasite. After Sanger sequencing, two results were further confirmed: or and or . The minimum infection rate for mosquitoes was 0.15% (eight positive pools/5285 mosquitoes). The study reveals a lower-than-expected natural infection rate (expected = 5.2% vs. observed = 0.15%). This low rate relates to the absence of monkeys as the main simian malaria reservoir in the studied region. Their absence was due to a significant population decline following the reemergence of yellow fever virus outbreaks in the Atlantic Forest from 2016 to 2019. However, this also indicates the existence of alternative reservoirs to infect mosquitoes. The found zoonotic species of , including the . -like parasite, may represent a simian malaria risk and thus a challenge for malaria elimination in Brazil.
PubMed: 37894123
DOI: 10.3390/microorganisms11102465 -
Proceedings (Baylor University. Medical... 2023is a genus of parasites that comprises different species. The species and are known to cause a vector-borne illness called malaria, and among these, is known to... (Review)
Review
is a genus of parasites that comprises different species. The species and are known to cause a vector-borne illness called malaria, and among these, is known to cause major complications. The vector, the Anopheles mosquito, is commonly found in warmer regions close to the equator, and hence transmission and numbers of cases tend to be higher in Sub-Saharan Africa, South Asia, and Central America. The number of cases of malaria in the United States has remained stable over the years with low transmission rates, and the disease is mostly seen in the population with a recent travel history to endemic regions. The main reason behind this besides the weather conditions is that economically developed countries have eliminated mosquitos. However, there have been reports of locally reported cases with in areas such as Florida and Texas in patients with no known travel history. This paper aims to familiarize US physicians with the pathophysiology, clinical features, and diagnostic modalities of malaria, as well as available treatment options.
PubMed: 37829240
DOI: 10.1080/08998280.2023.2255514