Stress in paradise: effects of elevated corticosterone on immunity and avian malaria resilience in a Hawaiian passerine

Vertebrates confronted with challenging environments often experience an increase in circulating glucocorticoids, which result in morphological, physiological, and behavioral changes that promote survival. However, chronically elevated glucocorticoids can suppress immunity, which may increase susceptibility to disease. Since the introduction of avian malaria to Hawaii a century ago, low elevation populations of Hawaii Amakihi (Chlorodrepanis virens) have undergone strong selection by avian malaria and evolved increased resilience (the ability to recover from infection), while populations at high elevation with few vectors have not undergone selection and remain susceptible. We investigated how experimentally elevated corticosterone affects the ability of high and low elevation male Amakihi to cope with avian malaria by measuring innate immunity, hematocrit, and malaria parasitemia. Corticosterone implants resulted in a decrease in hematocrit in high and low elevation birds but no changes to circulating natural antibodies or leukocytes. Overall, leukocyte count was higher in low than high elevation birds. Malaria infections were detected in a subset of low elevation birds. Infected individuals with corticosterone implants experienced a significant increase in circulating malaria parasites while untreated infected birds did not. Our results suggest that Amakihi innate immunity measured by natural antibodies and leukocytes is not sensitive to changes in corticosterone, and that high circulating corticosterone may reduce the ability of Amakihi to cope with infection via its effects on hematocrit and malaria parasite load. Understanding how glucocorticoids influence a host's ability to cope with introduced diseases provides new insight into the conservation of animals threatened by novel pathogens.

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Entomological Study on Transmission of Avian Malaria Parasites in a Zoological Garden in Japan: Bloodmeal Identification and Detection of Avian Malaria Parasite DNA From Blood-Fed Mosquitoes

Journal of Medical Entomology ◽

10.1603/me10197 ◽

2011 ◽

Vol 48 (3) ◽

pp. 600-607 ◽

Cited By ~ 29

Author(s):

Hiroko Ejiri ◽

Yukita Sato ◽

Kyeong-Soon Kim ◽

Tatsuko Hara ◽

Yoshio Tsuda ◽

...

Keyword(s):

Malaria Parasite ◽

Avian Malaria ◽

Zoological Garden ◽

Malaria Parasites ◽

Avian Malaria Parasite ◽

Avian Malaria Parasites ◽

Bloodmeal Identification

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Malaria Parasites and Packed Cell Volume of Free Range Poultry in Abeokuta metropolis, Ogun State, Nigeria.

NIGERIAN ANNALS OF PURE AND APPLIED SCIENCES ◽

10.46912/napas.10 ◽

2015 ◽

Vol 6 ◽

pp. 68-74

Author(s):

S O Sam-Wobo ◽

O O Malumi ◽

C F Mafiana ◽

B C Oganah ◽

O A Surakat

Keyword(s):

Cell Volume ◽

Packed Cell Volume ◽

Malaria Parasite ◽

Avian Malaria ◽

Hematological Parameter ◽

Malaria Parasites ◽

Free Range ◽

Ogun State ◽

Significant Difference ◽

Chi Square Analysis

Malaria parasites and packed cell volume offree range poultry was conducted on one hundred free range chickens collected from three communities in Abeokuta (Osiele, Lafenwa and Kuto). The results revealed that out of the 100 free range chickens examined, 13(13%) were infected with avian malaria parasite. Hematological parameter i.e. packed cell volume (PCV) revealed that chicken with PCV range 16-20 were 33.33% positive for malaria parasite. Others between PCV ranges 21 – 25 were 33.3%, while those between PCV ranges of 26 – 30 were 16.66% and those with PCV range of 31 – 35 were 16.67%.Chi-square analysis showed a significant difference between packed cell volume and malaria parasite(p<0.05). However, no significant difference was observed between sex and malaria parasite(p>0.05). The presence of avian malaria parasites in the study area could be of some epidemiological implications since the infected poultry could act as reservoir for malaria parasites.

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The transcriptome of the avian malaria parasite Plasmodium ashfordi displays host-specific gene expression

10.1101/072454 ◽

2016 ◽

Cited By ~ 1

Author(s):

Elin Videvall ◽

Charlie K. Cornwallis ◽

Dag Ahrén ◽

Vaidas Palinauskas ◽

Gediminas Valkiūnas ◽

...

Keyword(s):

Gene Expression ◽

Malaria Parasite ◽

Avian Malaria ◽

Molecular Mechanisms ◽

Gene Evolution ◽

Expression Profiles ◽

Specific Gene ◽

Malaria Parasites ◽

Specific Gene Expression ◽

Avian Malaria Parasite

AbstractMalaria parasites (Plasmodium spp.) include some of the world’s most widespread and virulent pathogens. Our knowledge of the molecular mechanisms these parasites use to invade and exploit hosts other than mice and primates is, however, extremely limited. It is therefore imperative to characterize transcriptome-wide gene expression from non-model malaria parasites and how this varies across host individuals. Here, we used high-throughput Illumina RNA-sequencing on blood from wild-caught Eurasian siskins experimentally infected with a clonal strain of the avian malaria parasite Plasmodium ashfordi (lineage GRW2). By using a multi-step approach to filter out host transcripts, we successfully assembled the blood-stage transcriptome of P. ashfordi. A total of 11 954 expressed transcripts were identified, and 7 860 were annotated with protein information. We quantified gene expression levels of all parasite transcripts across three hosts during two infection stages – peak and decreasing parasitemia. Interestingly, parasites from the same host displayed remarkably similar expression profiles during different infection stages, but showed large differences across hosts, indicating that P. ashfordi may adjust its gene expression to specific host individuals. We further show that the majority of transcripts are most similar to the human parasite Plasmodium falciparum, and a large number of red blood cell invasion genes were discovered, suggesting evolutionary conserved invasion strategies between mammalian and avian Plasmodium. The transcriptome of P. ashfordi and its host-specific gene expression advances our understanding of Plasmodium plasticity and is a valuable resource as it allows for further studies analysing gene evolution and comparisons of parasite gene expression.

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Host Specialization and Geographic Localization of Avian Malaria Parasites: A Regional Analysis in the Lesser Antilles

The American Naturalist ◽

10.2307/3473476 ◽

2005 ◽

Vol 165 (4) ◽

pp. 466

Author(s):

Fallon ◽

Bermingham ◽

Ricklefs

Keyword(s):

Avian Malaria ◽

Regional Analysis ◽

Host Specialization ◽

Lesser Antilles ◽

Malaria Parasites ◽

Avian Malaria Parasites

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Assessing Diversity, Plasmodium Infection and Blood Meal Sources in Mosquitoes (Diptera: Culicidae) from a Brazilian Zoological Park with Avian Malaria Transmission

Insects ◽

10.3390/insects12030215 ◽

2021 ◽

Vol 12 (3) ◽

pp. 215

Author(s):

Lilian de Oliveira Guimarães ◽

Roseli França Simões ◽

Carolina Romeiro Fernandes Chagas ◽

Regiane Maria Tironi de Menezes ◽

Fabiana Santos Silva ◽

...

Keyword(s):

Blood Meal ◽

Avian Malaria ◽

Mosquito Species ◽

Plasmodium Species ◽

Sao Paulo ◽

São Paulo ◽

Malaria Parasites ◽

Ecological Relationships ◽

Lack Of Information ◽

Avian Malaria Parasites

Avian malaria parasites are widespread parasites transmitted by Culicidae insects belonging to different genera. Even though several studies have been conducted recently, there is still a lack of information about potential vectors of Plasmodium parasites, especially in Neotropical regions. Former studies with free-living and captive animals in São Paulo Zoo showed the presence of several Plasmodium and Haemoproteus species. In 2015, a pilot study was conducted at the zoo to collect mosquitoes in order to find out (i) which species of Culicidae are present in the study area, (ii) what are their blood meal sources, and (iii) to which Plasmodium species might they be potential vectors. Mosquitoes were morphologically and molecularly identified. Blood meal source and haemosporidian DNA were identified using molecular protocols. A total of 25 Culicidae species were identified, and 6 of them were positive for Plasmodium/Haemoproteus DNA. Ten mosquito species had their source of blood meal identified, which were mainly birds, including some species that were positive for haemosporidian parasites in the former study mentioned. This study allowed us to expand the list of potential vectors of avian malaria parasites and to improve our knowledge of the evolutionary and ecological relationships between the highly diverse communities of birds, parasites, and vectors present at São Paulo Zoo.

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A cornucopia of research resources for the fourth rodent malaria parasite species

BMC Biology ◽

10.1186/s12915-021-01019-y ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Jane M. Carlton

Keyword(s):

Malaria Parasite ◽

Parasite Species ◽

First Century ◽

Model Systems ◽

Rodent Malaria Parasite ◽

Malaria Parasites ◽

Rodent Malaria ◽

Human Malaria ◽

Plasmodium Vinckei ◽

Research Resources

AbstractThe study of human malaria caused by species of Plasmodium has undoubtedly been enriched by the use of model systems, such as the rodent malaria parasites originally isolated from African thicket rats. A significant gap in the arsenal of resources of the species that make up the rodent malaria parasites has been the lack of any such tools for the fourth of the species, Plasmodium vinckei. This has recently been rectified by Abhinay Ramaprasad and colleagues, whose pivotal paper published in BMC Biology describes a cornucopia of new P. vinckei ‘omics datasets, mosquito transmission experiments, transfection protocols, and virulence phenotypes, to propel this species firmly into the twenty-first century.

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Malaria parasite detection in thick blood smear microscopic images using modified YOLOV3 and YOLOV4 models

BMC Bioinformatics ◽

10.1186/s12859-021-04036-4 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Fetulhak Abdurahman ◽

Kinde Anlay Fante ◽

Mohammed Aliy

Keyword(s):

Object Detection ◽

Malaria Parasite ◽

Blood Smear ◽

Clustering Algorithm ◽

State Of The Art ◽

Detection Accuracy ◽

Small Object ◽

Thick Blood Smear ◽

Malaria Parasites ◽

Microscopic Images

Abstract Background Manual microscopic examination of Leishman/Giemsa stained thin and thick blood smear is still the “gold standard” for malaria diagnosis. One of the drawbacks of this method is that its accuracy, consistency, and diagnosis speed depend on microscopists’ diagnostic and technical skills. It is difficult to get highly skilled microscopists in remote areas of developing countries. To alleviate this problem, in this paper, we propose to investigate state-of-the-art one-stage and two-stage object detection algorithms for automated malaria parasite screening from microscopic image of thick blood slides. Results YOLOV3 and YOLOV4 models, which are state-of-the-art object detectors in accuracy and speed, are not optimized for detecting small objects such as malaria parasites in microscopic images. We modify these models by increasing feature scale and adding more detection layers to enhance their capability of detecting small objects without notably decreasing detection speed. We propose one modified YOLOV4 model, called YOLOV4-MOD and two modified models of YOLOV3, which are called YOLOV3-MOD1 and YOLOV3-MOD2. Besides, new anchor box sizes are generated using K-means clustering algorithm to exploit the potential of these models in small object detection. The performance of the modified YOLOV3 and YOLOV4 models were evaluated on a publicly available malaria dataset. These models have achieved state-of-the-art accuracy by exceeding performance of their original versions, Faster R-CNN, and SSD in terms of mean average precision (mAP), recall, precision, F1 score, and average IOU. YOLOV4-MOD has achieved the best detection accuracy among all the other models with a mAP of 96.32%. YOLOV3-MOD2 and YOLOV3-MOD1 have achieved mAP of 96.14% and 95.46%, respectively. Conclusions The experimental results of this study demonstrate that performance of modified YOLOV3 and YOLOV4 models are highly promising for detecting malaria parasites from images captured by a smartphone camera over the microscope eyepiece. The proposed system is suitable for deployment in low-resource setting areas.

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Genome sequence, transcriptome, and annotation of rodent malaria parasite Plasmodium yoelii nigeriensis N67

BMC Genomics ◽

10.1186/s12864-021-07555-9 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Cui Zhang ◽

Cihan Oguz ◽

Sue Huse ◽

Lu Xia ◽

Jian Wu ◽

...

Keyword(s):

Dna Sequences ◽

Malaria Parasite ◽

Vaccine Development ◽

De Novo ◽

Gene Families ◽

Plasmodium Yoelii ◽

Control Measures ◽

Effective Control ◽

Malaria Parasites ◽

Rodent Malaria

Abstract Background Rodent malaria parasites are important models for studying host-malaria parasite interactions such as host immune response, mechanisms of parasite evasion of host killing, and vaccine development. One of the rodent malaria parasites is Plasmodium yoelii, and multiple P. yoelii strains or subspecies that cause different disease phenotypes have been widely employed in various studies. The genomes and transcriptomes of several P. yoelii strains have been analyzed and annotated, including the lethal strains of P. y. yoelii YM (or 17XL) and non-lethal strains of P. y. yoelii 17XNL/17X. Genomic DNA sequences and cDNA reads from another subspecies P. y. nigeriensis N67 have been reported for studies of genetic polymorphisms and parasite response to drugs, but its genome has not been assembled and annotated. Results We performed genome sequencing of the N67 parasite using the PacBio long-read sequencing technology, de novo assembled its genome and transcriptome, and predicted 5383 genes with high overall annotation quality. Comparison of the annotated genome of the N67 parasite with those of YM and 17X parasites revealed a set of genes with N67-specific orthology, expansion of gene families, particularly the homologs of the Plasmodium chabaudi erythrocyte membrane antigen, large numbers of SNPs and indels, and proteins predicted to interact with host immune responses based on their functional domains. Conclusions The genomes of N67 and 17X parasites are highly diverse, having approximately one polymorphic site per 50 base pairs of DNA. The annotated N67 genome and transcriptome provide searchable databases for fast retrieval of genes and proteins, which will greatly facilitate our efforts in studying the parasite biology and gene function and in developing effective control measures against malaria.

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