research topics in medical parasitology

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Parasitology is the scientific discipline concerned with the study of the biology of parasites and parasitic diseases, including the distribution, biochemistry, physiology, molecular biology, ecology, evolution and clinical aspects of parasites, including the host response to these agents.

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TBC9, an essential TBC-domain protein, regulates early vesicular transport and IMC formation in Toxoplasma gondii

A study suggests that TBC9, one of the Rab GTPase Activating Proteins, is crucial for early vesicular transport and inner membrane complex formation by regulating Rab2, Rab11A and Rab11B in Toxoplasma gondii .

• Shaojun Long

Tracing the origins of Plasmodium vivax resurgence after malaria elimination on Aneityum Island in Vanuatu

Sekine et al. traced the origins of Plasmodium vivax resurgence after achieving malaria elimination on Aneityum Island, Vanuatu. Analyzing five nuclear microsatellite markers, samples from the resurgence and nearby Tanna Island exhibit identical or closely related haplotypes, suggesting that imported infection contributes to the reintroduction.

• Chim W. Chan
• Akira Kaneko

Assessing the efficacy of the ovicidal fungus Mucor circinelloides in reducing coccidia parasitism in peacocks

• João Lozano
• Cristina Almeida
• Adolfo Paz-Silva

APEX2-based proximity proteomic analysis identifies candidate interactors for Plasmodium falciparum knob-associated histidine-rich protein in infected erythrocytes

• Sébastien Charneau
• Lucas Silva de Oliveira
• Julian C. Rayner

Effects of Eimeria acervulina infection on the luminal and mucosal microbiota of the cecum and ileum in broiler chickens

• Philip M. Campos
• Katarzyna B. Miska
• Monika Proszkowiec-Weglarz

Observing astrocyte polarization in brains from mouse chronically infected with Toxoplasma gondii

• Yaping Yuan

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How ignorance and gender inequality thwart treatment of a widespread illness

Tens of millions of people have female genital schistosomiasis, a neglected tropical disease that few physicians have even heard of. Efforts are under way to move it out of obscurity and empower women and girls to access sexual and reproductive health care.

• Claire Ainsworth

Cat parasite Toxoplasma tricked to grow in a dish

Cat-only life-cycle stage cultured in vitro , and the mysterious giant proteins that might turn bacteria into killers.

• Nick Petrić Howe
• Shamini Bundell

Urban malaria

This study provides evidence for a role of Anopheles stephensi in driving urban malaria outbreaks.

• Andrea Du Toit

Tropical diseases move north

As Earth warms, the creatures that spread neglected tropical diseases are gaining a foothold in Europe. Wealthy countries must prepare themselves for more cases.

Blood-sucking fish had flesh-eating ancestors

Two ‘superbly preserved’ fossil lampreys from the Jurassic period help piece together the past of the unusual jawless fish.

• Xiaoying You

Microsporidian spores contain hibernating dimeric ribosomes

Structural analysis reveals that spores of the microsporidium Spraguea lophii contain dimeric hibernating ribosomes.

• Elizabeth Weyer
• Louis M. Weiss

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Malaria prevalence and use of control measures in an area with persistent transmission in Senegal

Fassiatou Tairou, Ibrahima Gaye,  [ ... ], Roger C. K. Tine

A systematic review of the factors associated with malaria infection among forest rangers

Rahmat Dapari, Muhamad Zazali Fikri Mohd Yusop,  [ ... ], Mohd Erfan Edros

Comparative evaluation of the diagnostic accuracies of four different malaria rapid diagnostic test kits available in Ghana

Enoch Aninagyei, John Gameli Deku,  [ ... ], Richard Harry Asmah

Evaluation of genotoxic effect via expression of DNA damage responsive gene induced by ivermectin on MDBK cell line

Muhammad Muddassir Ali, Zainab Farhad,  [ ... ], Khalid Mehmood

Plasmodium falciparum ">Solution structure and pressure response of thioredoxin-1 of Plasmodium falciparum

Claudia Elisabeth Munte, Hans Robert Kalbitzer

Exploring coagulation parameters as predictive biomarkers of Plasmodium infection: A comprehensive analysis of coagulation parameters

Zelalem Tesfaye, Adane Derso,  [ ... ], Yalewayker Tegegne

Theileria annulata parasite with a single mutation, methionine 128 to isoleucine (M128I), in cytochrome B is resistant to buparvaquone">A Theileria annulata parasite with a single mutation, methionine 128 to isoleucine (M128I), in cytochrome B is resistant to buparvaquone

Shahin Tajeri, Debasish Chattopadhyay, Gordon Langsley, Ard M. Nijhof

Multi-group symbiotic evolutionary mechanisms of a digital innovation ecosystem: Numerical simulation and case study

Yuqiong Li, Liping Wu

Rapid and non-invasive detection of malaria parasites using near-infrared spectroscopy and machine learning

Maggy T. Sikulu-Lord, Michael D. Edstein,  [ ... ], Marina Chavchich

Parasitic contamination of fresh vegetables and fruits sold in open-air markets in peri-urban areas of Jimma City, Oromia, Ethiopia: A community-based cross-sectional study

Ahmed Zeynudin, Teshome Degefa,  [ ... ], Andreas Wieser

To live free or being a parasite: The optimal foraging behavior may favor the evolution of entomopathogenic nematodes

Víctor Trejo-Meléndez, Jorge Contreras-Garduño

Effect of egg production dynamics on the functional response of two parasitoids

María Aguirre, Guillermo Logarzo,  [ ... ], Octavio Augusto Bruzzone

Prevalence of intestinal parasitic infections and associated risk factors among patients attending Debarq Primary Hospital, northwest Ethiopia

Amir Alelign, Nigus Mulualem, Zinaye Tekeste

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Medical Parasitology Taxonomy Update, June 2020–June 2022

• Laboratory Medicine and Pathology

Research output : Contribution to journal › Article › peer-review

The taxonomy of medically important parasites continues to evolve. This minireview provides an update of additions and updates in the field of human parasitology from June 2020 through June 2022. A list of previously reported nomenclatural changes that have not been broadly adapted by the medical community is also included.

• Cryptosporidium
• apicomplexan parasites

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• Microbiology (medical)

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• Parasitology Medicine & Life Sciences 100%
• Parasites Medicine & Life Sciences 57%

T1 - Medical Parasitology Taxonomy Update, June 2020–June 2022

AU - Mathison, Blaine A.

AU - Bradbury, Richard S.

AU - Pritt, Bobbi S.

N1 - Publisher Copyright: Copyright © 2023 American Society for Microbiology. All Rights Reserved.

PY - 2023/5

Y1 - 2023/5

N2 - The taxonomy of medically important parasites continues to evolve. This minireview provides an update of additions and updates in the field of human parasitology from June 2020 through June 2022. A list of previously reported nomenclatural changes that have not been broadly adapted by the medical community is also included.

AB - The taxonomy of medically important parasites continues to evolve. This minireview provides an update of additions and updates in the field of human parasitology from June 2020 through June 2022. A list of previously reported nomenclatural changes that have not been broadly adapted by the medical community is also included.

KW - Babesia

KW - Cryptosporidium

KW - Giardia

KW - Plasmodium

KW - apicomplexan parasites

KW - cestodes

KW - nematodes

KW - protozoa

KW - taxonomy

KW - trematodes

UR - http://www.scopus.com/inward/record.url?scp=85160019944&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85160019944&partnerID=8YFLogxK

U2 - 10.1128/jcm.00286-22

DO - 10.1128/jcm.00286-22

M3 - Article

C2 - 36809084

AN - SCOPUS:85160019944

SN - 0095-1137

JO - Journal of clinical microbiology

JF - Journal of clinical microbiology

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From its founding in 1916, the Johns Hopkins Bloomberg School of Public Health has made parasitology research a priority.

Malaria, yellow fever, amebiasis, trypanosomiasis and helminths were important public health problems, and hookworm was a major concern of the Rockefeller Foundation, the top donor to the School of Hygiene and Public Health.

Chair Robert William Hegner observed that “zoologists who are interested in parasitology usually direct their attention to the parasite [morphology, life history and systematics], whereas most physicians tend to emphasize the reactions of the host [symptomology, pathology and therapeutics]. Only when these two phases are brought together and when aspects of the subject peculiar to the public health activities are added is a complete program realized: then parasitology becomes the biology of host-parasite relationships.”

Research Groups

Dr. Peter Agre’s  laboratory studies the influence of both human and malaria parasite aquaporins on malaria infection. During the rapid growth of malarial parasites within red blood cells, glycerol is taken up by the parasites and incorporated into lipids for membrane biosynthesis. The glycerol must cross the red blood cell plasma membrane and the parasitic plasma membrane to become accessible for the parasite. The group has shown that aquaglyceroporins are expressed in both membranes in mice. Host aquaporin 9 (AQP9) is expressed in the red blood cell plasma membrane and parasite aquaglyceroporin (PbAQP) is expressed in the parasite plasma membrane. The glycerol transport pathway contributes to the virulence of  Plasmodium  intraerythrocytic stages during malarial infection. Host aquaporins are also being studied in brain, where AQP4 serves to protect against cerebral malaria. These efforts will provide better understanding of the biology of malaria and may lead to better methods to control or treat malaria.

The laboratory of  Dr. Isabelle Coppens  studies the adaptations of apicomplexan parasites to their host mammalian cells that lead to disease pathology. The phylum of Apicomplexa includes human pathogens such as Plasmodium, the causative agent of malaria, Toxoplasma and Cryptosporidium, two leading opportunistic pathogens of immunocompromised individuals.  By entering into the confines of a cell, these parasites assure themselves a ready source of nutrients and protection from immune confrontations. We are analyzing the microbial genes and pathways involved in the co-option of host cell processes and organelles by Apicomplexa including the host cytoskeleton and membrane traffic during infection, the salvage of host lipids and the remodeling of the parasitophorous vacuole to support parasite differentiation and replication. We focus on the pathogenic mechanisms at the host-parasite interface that represent interesting targets for the development of therapeutic strategies against Apicomplexa infections.

Dr. Monica Mugnier’s  laboratory studies antigenic variation in the African trypanosome,  Trypanosoma brucei . These deadly parasites evade recognition by the immune systems of the humans and animals they infect by “switching” a dense surface coat made up of a protein known as variant surface glycoprotein, or VSG.  T. brucei  can extend its repertoire of VSGs beyond those encoded in the genome through recombination events that create new, antigenically distinct variants. This diversification of the VSG repertoire to create new antigen coats is critical for the parasite to maintain a chronic infection. The Mugnier lab uses bioinformatics and other high-throughput approaches to better understand the dynamics of antigenic variation and the mechanisms driving VSG diversification in vivo.

Malaria parasites contain two organelles, the apicoplast and the mitochondrion, which are thought to have arisen through the incorporation of other cells into the parasite.  Due to the prokaryotic origin of these organelles, they contain a range of metabolic pathways that differ significantly from those of the human host.  Dr. Sean Prigge’s  laboratory is investigating biochemical pathways found in these organelles, particularly those that are dependent on the enzyme cofactors lipoate, biotin and iron-sulfur clusters. We are interested in these three cofactors, how they are acquired, how they are used, and whether they are essential for the growth of malaria parasites.

At any given time, helminth parasites (nematodes, trematodes, tape worms) infect over a third of the human population. These long-lived multicellular parasites, which typically establish infection that last for months to decades, induce immune responses that result in a fundamental change the immune status of infected individuals.  Dr. Alan Scott  investigates the impact of parasitic nematodes on host immunity with special emphasis the function of macrophages in the lungs. In addition, Dr. Scott investigates the role of lung macrophages in regulating the inflammatory response induced against malaria-infected red blood cells that sequester in the pulmonary environment. 

Schistosomes are unique parasites of the blood system that occupy a niche in the venous capillaries draining the small intestine (Schistosoma mansoni or S. japonicum) and the bladder (S. haematobium). These parasites cause severe pathology in the liver in the case of the first two and the bladder in the case of the third. In fact in the bladder, the infection is associated with the development of bladder cancer.  Dr. Clive Shiff  is interested in the mechanisms in the development of this cancer resulting from chronic infection, detecting changes in early stages of the infection and also in methods to improve the diagnosis of these infections by using DNA detection. The objective is to improve epidemiological method to assess the public health impact of the parasite.

Dr. Photini Sinnis  and her group are focused on understanding the fundamental biology of the pre-erythrocytic stages of malaria. This includes sporozoites, the infective stage of the malaria parasite, and the liver stages into which they develop. This is an understudied yet critically important area of investigation as this is when malaria infection is established in the mammalian host. The goals of their research are to: 1) elucidate the molecular interactions required for the sporozoite’s journey from mosquito midgut to mammalian liver; 2) understand the events involved in hepatocyte invasion; 3) translate their findings to develop drugs and a vaccine that target these stages of the malaria parasite.

Research in  Dr. Prakash Srinivasan’s  laboratory is focused on understanding the molecular basis of host cell invasion by the human pathogen  Plasmodium falciparum . Clinical disease is caused by the exponentially growing malaria parasites within the red blood cell (RBC). This blood stage infection begins when merozoites (invasive forms) make contact with RBCs through specific ligand-receptor interactions that activate intracellular signaling, both in the parasite and the RBC, to facilitate parasite entry. Many of these signaling pathways are conserved and function also during sporozoite (another invasive form) invasion of hepatocytes (liver). We use complementary approaches such as conditional genome editing techniques, live cell imaging, small molecule inhibitors and quantitative proteomics to study the function of invasion determinants in this complex process. We leverage this knowledge to develop and validate new antimalarial vaccine and drug targets using  in vitro  and  in vivo  model systems.

Dr. David Sullivan  and his laboratory work on Plasmodium molecular biology related to iron metabolism, which also intersects with heme crystallization, the target of the antimalarial quinolone drugs. and Bioavailable iron also plays a critical role in the activation of the another class of antimalarial drug, the artemisinins. Work on cerebral malaria and severe anemia involves the human endothelial response to Plasmodium and contribution of Plasmodium hemolysins to anemia. A general principle of infectious diseases is accurate diagnosis and effective treatment and the laboratory works on novel saliva or urine malaria diagnostics as well as new malaria uses for already existing FDA approved drugs. An epidemiologic study in Bangladesh is probing the role of hemoglobin E on outcome and transmission risk amongst other human, parasite and vector factors. Ongoing work on helminthes includes filiariasis and schistosomiasis.

Medical Parasitology

• © 2017
• Rohela Mahmud 0 ,
• Yvonne Ai Lian Lim 1 ,
• Amirah Amir 2

Fac. of Medicine, Dept. of Parasitology, University of Malaya, Kuala Lumpur, Malaysia

You can also search for this author in PubMed   Google Scholar

• Deals with all aspects of medical parasitology in an easy-to-understand manner
• Offers a collection of detailed medical case reports from first hand experiences from the authors and colleagues
• Provides examples of test questions and scenarios for the reader
• Includes supplementary material: sn.pub/extras

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Table of contents (14 chapters)

Front matter, introduction.

Rohela Mahmud, Yvonne Ai Lian Lim, Amirah Amir

Protozoa and Helminths

Intestinal and genital flagellates, hemoflagellates, malaria parasites and babesia, microsporidia, nematodes: roundworms, cestodes: tapeworms, trematodes: flukes, ectoparasites of medical importance, case reports, back matter.

• host-parasite interaction
• infectious diseases
• antibacterial drug resistance

About this book

This textbook will provide a systematic comprehension of the various medically important human parasites; their distribution, habitat, morphology and life cycle, pathogenesis and clinical features, laboratory diagnosis, treatment, prevention and control. The main emphasis is on the protozoan and helminthic diseases, also medical entomology covering vectors relevant to these diseases.

The book aims to promote an easy yet comprehensive way of learning parasitology. It attempts to break down the complexity of medical parasitology into parts that are easy to understand yet integrating the essential information of parasitic infections. The integration of knowledge of parasites will be achieved through student friendly illustrations, inclusion of a collection of recent case reports, examples of test questions and scenarios, and the images of human parasites. Essentially, it provides a “one-stop learning package” for medical parasitology. 

Authors and Affiliations

About the authors, bibliographic information.

Book Title : Medical Parasitology

Book Subtitle : A Textbook

Authors : Rohela Mahmud, Yvonne Ai Lian Lim, Amirah Amir

DOI : https://doi.org/10.1007/978-3-319-68795-7

Publisher : Springer Cham

eBook Packages : Biomedical and Life Sciences , Biomedical and Life Sciences (R0)

Copyright Information : Springer International Publishing AG 2017

Softcover ISBN : 978-3-319-68794-0 Published: 08 February 2018

eBook ISBN : 978-3-319-68795-7 Published: 31 January 2018

Edition Number : 1

Number of Pages : XI, 191

Number of Illustrations : 82 illustrations in colour

Topics : Parasitology , Infectious Diseases , Drug Resistance

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Direct medical programs, often referred to as BS/MD programs, are some of the most competitive programs in the country. With programs at Baylor University, Brown University and Case Western Reserve University accepting less than 3% of all its applicants, these programs are often more competitive than the Ivy League. They are looking for exceptional students who are completely committed to becoming physicians. That means the students have spent the better part of their high school career pursuing STEM-focused activities, including physician shadowing, volunteering in healthcare settings and leadership positions in clubs.

Many BS/MD hopefuls pursue research as a way to build their resume.

Numerous BS/MD programs like Rensselaer Polytechnic University, like to see students with extensive research experience. Its program, aptly named the Physician-Scientist Program, wants to see students who will not only participate in research during their tenure in the program but also lead and create their own research projects. The University of South Carolina’s Accelerated Undergraduate to M.D. program has an extensive research and thesis component that is required throughout the student’s academic career. The University of Rochester offers funding for summer research for its BS/MD students. Similarly, the University of Illinois at Chicago looks for students who can demonstrate their “research aptitude.”

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When BS/MD admission officers review applications, they don’t pit one type of experience against another. They know not every student will be able to find a local professor who allows them to research with them or can afford to do a paid summer program that spans numerous weeks or months. Consequently, they typically will consider holistically the depth of a student’s research experience, irrespective of the type of research the student completes.

Virtual Or In-Person Programs?

Both virtual and in-person experiences can add value to a BS/MD application. However, it depends on the program’s learning objectives and deliverables. Some students don’t have the flexibility to travel to an in-person camp and spend multiple weeks or months there. The University of Pittsburgh’s Guaranteed Admission Program says that “while in-person experiences are encouraged, virtual or remote experiences will be considered when evaluating the applicant.” For those students who have other obligations, a virtual camp might be the perfect fit and still offer a valuable experience.

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The research experience doesn’t necessarily have to align with the student’s research interests, but it can often be helpful if it does. However, BS/MD admission officers know that high school students are still exploring their interests, which will likely evolve over the years. An opportunity that doesn’t align with the student’s interest will still be valuable because it allows the student to gain valuable skills that they can leverage to other research experiences in the future.

Summer programs might give students a chance to explore dual interests. Some students interested in medicine might also want to explore computer science or Artificial Intelligence, so finding an opportunity that allows them to blend those interests might be ideal. For example, Rising Researchers , a sister company of Moon Prep, is hosting two five-week summer camps that allow students to practice AI and Machine Learning to study human diseases. Other camps, like Penn Summer Academies, allow students to apply coding skills to other areas of study.

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For students who find an independent research experience, the relationship might span several months or even years. Those experiences might result in more fruitful research results and a strong relationship between the student and the mentor.

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An experience resulting in a research publication is an added bonus, but it isn’t a requirement. If a student writes a research paper, even if not published, can still demonstrate the student’s scientific writing ability and add value to their college application.

Every BS/MD program is different, and the admission officers' value of research might vary from program to program. Ultimately, BS/MD programs are looking for students who are passionate about medicine and have had extensive experiences to affirm that passion. The College of New Jersey stated in an interview with Moon Prep that they are looking for passionate students, be it a deep involvement in Boy Scouts, Taekwondo or music. Therefore, students should never feel obligated to research if it does not align with their interests. Being genuine in their activities and demonstrating their passions is how to build a resume that stands out to BS/MD admission officers.

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Medical Parasitology Taxonomy Update, June 2020–June 2022

Blaine a. mathison.

a Institute for Clinical and Experimental Pathology, ARUP Laboratories, Salt Lake City, Utah, USA

Richard S. Bradbury

b Federation University, Melbourne, Victoria, Australia

Bobbi S. Pritt

c Division of Clinical Microbiology, Mayo Clinic, Rochester, Minnesota, USA

The taxonomy of medically important parasites continues to evolve. This minireview provides an update of additions and updates in the field of human parasitology from June 2020 through June 2022. A list of previously reported nomenclatural changes that have not been broadly adapted by the medical community is also included.

INTRODUCTION

Taxonomic revisions have a significant impact on the practice of the clinical microbiology laboratory. It is important that clinical microbiologists remain abreast of these changes to ensure the accuracy and completeness of laboratory reports, and so that clinicians acting on these reports can easily access the most recent clinical information about any reported organisms. It is advisable that laboratories adopt the most up-to-date nomenclatural changes in a timely fashion, although to avoid confusion, they may also wish to note the previous name of an organism on their reports for 2 to 3 years after a revision is enacted.

In recent years, the increasing use of molecular tools in parasitology has led to the taxonomic reassignment and revision of medically important parasites. Furthermore, several species of parasites have been identified, for the first time, as affecting human hosts in the past 2 years. Combined with prior published taxonomic updates ( 1 , – 3 ) and a recent checklist on the eukaryotic parasites of humans ( 4 ), this document allows a comprehensive review of changes in nomenclature applicable to medical parasitology since 2012.

A systematic review was conducted using several reference materials to identify peer-reviewed studies describing parasite taxonomic changes and newly reported parasites of clinical importance, published between June 2020 through June 2022, continuing from the previous 3 Medical Parasitology Taxonomic Updates (1–3). A systematic literature search of the PubMed database (U.S. National Library of Medicine National Institutes of Health; https://www.ncbi.nlm.nih.gov/pubmed ), Google Scholar ( https://scholar.google.com/ ), and Google ( https://www.google.com ) was performed using the keyword search phrases such as “nov. sp.” and “new parasite X human” and “novel parasite humans” to identify newly described taxa, including from non-English publications that came up in search queries. Only parasites reported from human specimens were included. The U.S. Centers for Disease Control and Prevention's Division of Parasitic Diseases and Malaria (DPDM) DPDx website ( https://www.cdc.gov/dpdx/ ) was also consulted.

REVISED AND NEW TAXA

Revised and new parasite taxa, reported from June 2020 through June 2022 that were not included in the previous version of the taxonomy updates, are listed in Tables 1 and ​ and2, 2 , respectively, along with their clinical relevance. Diagnostic laboratory methods are also provided for the new taxa. Established taxa that have older nomenclatural changes that are not commonly implemented in clinical and diagnostic laboratories are listed in Table 3 .

Changes in parasite taxa from June 2020 to June 2022

Parasite taxa newly described or reported from humans from June 2020 to June 2022

Previous nomenclatural changes that have not yet been broadly adapted by the medical community

Revised taxa.

(i) Babesia . In 2007, a novel strain of Babesia was reported from a 75-year-old female in Korea. Based on sequencing of the 1684 bp region of the 18S rRNA gene, the isolate was distant from other human Babesia spp. and shared a 98% sequence identity with a Babesia detected in sheep in China. The isolate from the human patient was designated strain KO1 ( 5 ). In 2019, a second case of babesiosis was reported in Korea, this time from a 70-year-old male (isolate KCDC-1). Molecular studies showed similarities to Chinese ovine Babesia and strain KO1 from the first human patient in Korea based on phylogenetic comparison of the sequences from the same 18S rRNA region. Phylogenetic comparison of a 554 bp sequence of cytochrome b ( cob ), and 554 bp of the cytochrome c oxidase subunit III gene ( cox 3) showed Babesia KO1 is nestled within the B. motasi clade, along with ovine strains ( 6 ). The vectors of these Babesia species are not known, but their DNA has been detected in Haemaphysalis longicornis ticks ( 6 ). Further phylogenetic studies, such as comparison of the whole mitochondrial genome sequences of KO1, KCDC-1, and B. motasi , are required to determine whether these isolates represent B. motasi or novel cryptic sibling species.

(ii) Dirofilaria . In 2021, Candidatus Dirofilaria hongkongensis was described from humans and dogs in Hong Kong ( 7 ). It has subsequently been detected in humans and wild and domestic canids from India ( 8 , – 10 ). While molecular analysis supports a potential novel species, the original authors failed to designate a holotype specimen or provide a morphologic description, both of which are required by the International Code of Zoological Nomenclature, which governs scientific names for parasites ( 11 ). In addition, the designation of ‘candidatus’ is not used in zoological nomenclature as it is with prokaryotes and fungi (which are governed by The International Code of Nomenclature of Prokaryotes and The International Code of Botanical Nomenclature, respectively). Thus, Candidatus Dirofilaria hongkongensis should be considered nomen nudum ( 11 ) (i.e., a proposed name that is invalid as the designation has no nomenclatural status), and isolates should be referred to the genus level only or as Dirofilaria sp. Genotype Hong Kong.

(iii) Spirometra. Spirometra spp. are diphyllobothriid cestode parasites of canids and felids. Infection occurs from the ingestion of infected intermediate or paratenic hosts, such as reptiles and amphibians ( 12 , 13 ). Humans may rarely be accidental intermediate hosts or, very rarely, may be definitive hosts ( 14 ). In 2020, a sparganum removed from a mass in the left upper eyelid of a 22-year-old man in Thailand was reported as Spirometra ranarum . This definitive identification was made by sequencing 4 regions of cox1 ( 13 ). However, subsequent revisions and corrections made by Yamasaki, et al. ( 15 ) and Kuchta, et al. ( 16 ) have demonstrated that many species identifications for various Spirometra spp. available on GenBank are incorrect. These authors both note that “ Spirometra erinaceieuropei ” and “ Spirometra decipiens ” reports from Asia represent misidentifications of Spirometra mansoni ( 15 , 16 ). They further determined that the species “ Spirometra ranarum ” reported from Asia and Africa is conspecific with (i.e., belonging to the same species as) Spirometra mansoni ( 15 , 16 ). BLASTN analysis of the aforementioned human ocular “ S. ranarum ” isolate from Thailand (GenBank isolate {"type":"entrez-nucleotide","attrs":{"text":"MT590763.1","term_id":"1851978945","term_text":"MT590763.1"}} MT590763.1 ) demonstrated 100% sequence identity with the cox1 sequence identified by Yamasaki, et al. as Spirometra mansoni ( 15 ).

The above findings highlight the challenges of inaccurate parasite identifications assigned to some sequences in sequence read archives (SRAs). In most cases, this has been caused by misidentifications of the parasite species from which the nucleic acid was obtained. Review of current parasite identifications and sequences in GenBank and other SRAs is advisable. In the future, the establishment of parasites reference sequences, where the identity of the species has been confirmed by morphological and molecular experts in the field and a tagged museum specimen is available for later reference, would resolve this problem.

(i) Cryptosporidium . Cryptosporidium ryanae is a widespread parasite of cattle and deer that was originally designated Cryptosporidium deer-like genotype ( 17 ). A 2019 study in India looking at the prevalence of Cryptosporidium in dairy cattle, farm workers, and environmental specimens revealed the presence of C. ryanae in human stool specimens. Identification was made by sequencing 490 bp of 18S rRNA and 302 bp of hsp70 ( 18 ).

Cryptosporidium sp. horse genotype VIa is a currently undescribed Cryptosporidium that has been documented parasitizing horses and donkeys. In 2022, an isolate of this genotype was detected in a 13-year-old girl in Poland who was undergoing immunosuppressive therapy for juvenile rheumatoid arthritis and Crohn’s disease ( 19 ). The identification was made based on sequence analysis of a 774 bp region of 18S rRNA and 770 bp of gp60 ( 19 ). An epidemiologic investigation revealed that the patient rode horses once a week at a riding stable; stool was collected from 10 horses at the stable and one of the horses ridden by the patient was PCR positive for Cryptosporidium with 100% sequence identity with the isolate from the patient ( 19 ). While this is the first time Cryptosporidium horse genotype VIa has been isolated from a human, a related genotype, Cryptosporidium horse genotype VIb, was previously isolated from a pet store employee in NM, USA who presented with diarrhea, fever, loss of appetite, body aches, nausea, abdominal cramps, and fatigue ( 20 ). No history of immunosuppression for the patient was reported ( 20 ).

(ii) Simplicimonas . Simplicimonas similis is a parasitic trichomonad that was originally described from a gecko ( 21 ). It has also been isolated from carabao in the Philippines ( 22 ). In a 2018 study looking at intestinal parasites in symptomatic and asymptomatic people in Madagascar, S. similis was detected in the stool of a single patient by PCR and sequencing of a 1449 bp region of 18S rRNA ( 23 ). After that initial detection, the authors developed a conventional PCR assay specific for a 260 bp region of S. similis 18S rRNA and retested all other study samples by PCR and sequencing; S. similis was detected in 3 additional subjects, 2 of which presented with general intestinal symptoms (but who were also infected with other gastrointestinal protozoans) ( 23 ). One of the positive subjects, 2 of his family members, and their zebu were retested a year later; all 3 patients and the zebu ( Bos taurus indicus ) were positive for S. similis by 18S rRNA PCR and sequencing ( 23 ). Simplicimonas similis has yet to be detected by microscopy in human stool specimens, and the presence of S. similis DNA in these patients’ stools does not rule-out out the possibility of spurious passage following the consumption of food or water contaminated with S. similis .

(iii) Plasmodium . Plasmodium coatneyi , P. inui , and P. simiovale are parasites of nonhuman primates in Southeast Asia ( 24 ). In 2021, surveillance of Plasmodium species in forest fringe-living indigenous people in Malaysia resulted in the detection of 8 Plasmodium species, including P. coatneyi and P. inui , by sequencing of a 914 bp - 950 bp region of the 18S rRNA ( 25 ). While these species have already been shown to infect humans under experimental conditions, this represents the first time these 2 species have been detected in naturally-infected people. New DNA extractions were prepared from the blood positive for P. coatneyi and P. inui , and were sent to a second facility that tested them by sequencing a 925 bp - 935 bp region of cox1 . At the second facility, the specimens positive for P. inui tested positive for a Plasmodium inui -like species, 2 of which also tested positive for a co-infection with P. simiovale (and 1 of those was a triple infection with P. cynomolgi ). In a separate study, also in Malaysia in 2021, P. inui was detected in 2 humans using nested PCR ( 26 ).

The specimens positive for P. coatneyi at the first facility tested negative at the second facility. This discrepancy might be attributable to the absence of parasite DNA in the extracted second blood sample due to exceptionally low parasitemia, or due to a higher limit of detection in the PCR assay at the second site. Regardless, it is not thoroughly explained and does indicate a need for further investigation of the P. coatneyi infections reported. Unfortunately, microscopy was not performed on any of the samples, and, therefore, no data on the morphology of these species in humans, nor confirmation of the infections by what remains the gold standard for malaria diagnosis, was possible.

Plasmodium cynomolgi , P. simiovale , and P. inui are morphologically very similar to P. vivax , P. ovale , and P. malariae , respectively, and P. coatneyi is morphologically similar to P. knowlesi , which itself shares morphologic similarities to P. falciparum and P. malariae . This could demonstrate the necessity of molecular confirmation in patients with travel history to regions where zoonotic Plasmodium species occur and share morphologic similarities to human Plasmodium species.

(iv) Babesia . A recent survey of 12 subjects with clinical babesiosis in ON, Canada detected 2 people infected with Babesia odocoilei ( 27 ). The species identification was confirmed in both cases by sequencing a 440 bp region of the Babesia 18S rRNA gene. Both subjects had intact spleens, and neither were immunocompromised, but they presented with clinical signs and symptoms consistent with babesiosis; however, blood films were not performed on either of the patients. Babesia odocoilei may be found infecting primarily white-tailed deer ( Odocoileus virginianus ), but also other cervid species throughout North America ( 27 , 28 ). The vector tick is Ixodes scapularis . Dermacentor spp. may be responsible for transmission in Saskatchewan, where I. scapularis is not found, though the vector competence of Dermacentor for B. odocoilei is not confirmed ( 28 ).

(v) Anthemosoma . Anthemosoma garnhami is a piroplasm originally described from spiny mice in Ethiopia ( 29 ). In 2021, A. garnhami was detected in the blood of a 24-year-old HIV-positive male presenting with hemolytic anemia in South Africa who was originally from Zimbabwe ( 30 ). The initial diagnosis was made by the finding of Babesia -like organisms on peripheral blood films stained with Giemsa. The definitive identification was made by sequencing a 400 bp region of 18S rRNA ( 30 ). Anthemosoma garnhami should be in the differential of patients from Africa presenting with Babesia -like organisms microscopically. The vector of A. garnhami remains unknown, but is likely an ixodid tick ( 23 ).

(vi) Leishmania . Leishmania ( Sauroleishmania ) tarentolae is a parasite of lizards, and is transmitted by sand flies in the genus Sergentomyia ( 31 , 32 ). In 2020, L. tarentolae was detected by PCR in the blood of 3 blood donors in Italy by sequencing of a 286 bp of 5.8S rRNA ( 33 ). The following year, L. tarentolae was detected in multiple human hosts by serology (IFA) and molecular testing of blood (PCR and sequencing of a 276 bp −278 bp region of the ITS1 gene) ( 31 ).This is supported by prior molecular detection of L. tarentolae (76 bp of kinetoplastid DNA) in the intestines and bone marrow of a 300-year-old mummified corpse from Brazil, likely of a European immigrant ( 34 ). The clinical presentation of human infection with L. tarentolae is undescribed, may be nonpathogenic to humans ( 33 ), and may present a potential vaccine candidate for pathogenic human Leishmania spp ( 35 ).

(vii) Hymenolepis sp. AN-2015. An adult Hymenolepis sp. tapeworm was recovered from the stool of a 52-year-old Tibetan woman who was part of an epidemiologic study for teniasis and cysticercosis in Sichuan, China ( 36 ). Based on 28S rRNA (1243 bp) and cox1 (1000 bp) sequencing ( 36 ), the cestode was identified as closely related to H. hibernia , a parasite of mice in the genus Apodemus in Europe and Asia ( 37 ). Eggs recovered from the proglottids averaged 63 μm in diameter, had a thick shell with striations, and lacked polar filaments ( 36 ). These features are not consistent with either of the more familiar parasites of humans, Rodentolepis (formerly Hymenolepis ) nana or H. diminuta , although there is some similarity to the latter. Other zoonotic hymenolepid cestodes should be considered when egg morphology does not fit traditional species reported from humans.

(viii) Breinlia . Breinlia annulipapillata is an ocular parasite of kangaroos and wallabies in Australia, and is transmitted by mosquitoes ( 38 ). In 2021, an adult B. annulipapillata was recovered from the subconjunctiva of a 73-year-old man in Australia ( 38 ). The identification of B. annulopapillata was made by sequencing 830 bp of 18S rRNA and 650 bp of cox1 ( 38 ). Other zoonotic filarial nematodes should be considered when nematodes are recovered from the eye, especially in geographic areas where more familiar taxa, such as Loa loa or Dirofilaria species (non- immitis ) do not occur or are very rarely reported.

(ix) Dirofilaria . A potentially novel, unnamed, Dirofilaria species infecting a 75-year-old male in Japan was reported in 2019. This case presented with a non-tender, immobile, sub-cutaneous nodule to the left of the umbilicus. After excision, a Dirofilaria with prominent cuticular ridges was identified on histology ( 39 ). A short (200 bp) sequence of 12S rRNA showed more than 9% divergence from other published Dirofilaria spp. sequences, with its closest relative being Dirofilaria ursi ( 39 ).

(x) Dracunculus . In 2021, an unknown and potentially novel species of Dracunculus was recovered from the leg of a 23-year-old male in Vietnam who presented with skin abscesses, a loss of appetite, lethargy, muscle weakness, and eosinophilia ( 40 ). The identification of Dracunculus was made based on morphologic criteria and sequencing of the whole 1820 bp 18S rRNA gene. The morphologic and molecular data rule-out the Guinea worm, D. medinensis , and most other mammalian Dracunculus species. L1 larvae recovered from the adult worm were morphologically similar to some reptilian Dracunculus species ( 40 ). Although this specimen does not have a species name yet, we are including it for completeness until a species can be determined or described.

(xi) Versteria . Versteria is a genus of cestodes that parasitizes mustelid carnivores as definitive hosts and rodents as intermediate hosts ( 41 ). In 2018 and 2019, there were 2 reports of human infection with Versteria . In both cases, the patients presented with extraintestinal infection by the metacestode (larval) stage of the parasite. The first patient was a 53-year-old female kidney transplant recipient from Atlantic Canada ( 42 ). Imaging showed a large hepatic lesion with multiple satellite nodules. A laparoscopic liver biopsy revealed a necrotizing granuloma surrounding a single protoscolex. Two screening EIAs for Echinococcus granulosus were positive, but 2 screening EIAs for E. multilocularis were negative. Immunoblot testing for both E. granulosus and E. multilocularis were negative. Molecular testing of a 264 bp region of 12S rRNA from a needle biopsy sample showed 98% sequence identity with Versteria isolated from a captive orangutan ( 42 ).

The second case was in a 68-year-old woman in PA, USA who presented with nodular lesions in her lungs, liver, and kidneys, and cyst-like lesions in her eye and brain ( 41 ). Histopathology revealed a cestode-like tegument and calcareous corpuscles consistent with a metacestode infection, but no protoscoleces were observed ( 41 ). Immunoblot testing for T. solium was negative. A 128 bp region of cox1 in DNA extracted from a formalin-fixed paraffin-embedded (FFPE) liver biopsy was sequenced, and demonstrated 98% sequence identity with Versteria ( 41 ). The patient had contact with fishers, which are mustelids that can probably serve as competent hosts for the cestode, on her property; she had noted a recent resurgence of fishers in the area ( 41 ). These cases highlight that other zoonotic cestodes should be considered when morphological or serologic results cannot confirm more familiar taxa ( Taenia solium , Echinococcus spp., etc.).

(xii) Philophthalmus . Philophthalmus is a genus of trematodes that parasitize the eyes of animals, particularly waterfowl and shorebirds. In 2022, a novel Philophthalmus species was recovered from the eyes of 2 patients in Japan ( 43 ). The species was described as P. hechingeri , based on morphologic criteria ( 43 ). The natural definitive hosts are unknown but are presumed to be shorebirds. Molecular analysis of the mitochondrial DNA made it possible to link the parasite to its molluskan host, Batillaria attramentaria ( 43 ).

(xiii) Dermacentor . Dermacentor variabilis is a medically important tick in North America that is responsible for the transmission of the agents of Rocky Mountain spotted fever and tularemia, and has been implicated as a cause of tick paralysis ( 44 ). Historically, D. variabilis was described as having 2 disjunct populations; 1 throughout much of eastern North America, and 1 along the Pacific Coast and Intermountain Region west of the Rocky Mountains. Prior work sequencing of mitochondrial markers ( cox1 and 16S rRNA ) demonstrated that these 2 populations represented distinct genetic clades. In 2021, D. variabilis was divided into 2 species, D. variabilis in the East and D. similis in the West, based on morphologic features and molecular analysis using double digest restriction-site associated DNA sequencing on an Illumina HiSeq ( 45 ). With the splitting of D. variabilis into 2 species, a reassessment of their vector competence and their role in the transmission of infectious agents may be necessary ( 45 ).

(xiv) Palpada scutellaris . Palpada scutellaris is a North American hover fly in the family Syrphidae. Larvae typically live in damp areas rich in organic materials where they feed by filtering suspended food. In 2020, the first reported case of intestinal myiasis caused by P. scutellaris was reported in a 68-year-old Costa Rican woman who presented with intestinal pain and bloody diarrhea ( 46 ). The larvae were reportedly found alive in her stool and were identified as P. scutellaris based on morphologic criteria ( 46 ). The topic of intestinal myiasis is currently controversial, and given the natural habitat of syrphid larvae, one must consider the presence of the larvae in the stool was incidental and may represent post-defecation contamination. We are including the report here for completeness, but readers should exercise caution when interpreting this and other findings in the absence of physical evidence that syrphid fly larvae can cause myiasis.

Two decades of studies suggest health benefits associated with plant-based diets

But researchers caution against broad diet recommendations until remaining knowledge gaps are filled.

Vegetarian and vegan diets are generally associated with better status on various medical factors linked to cardiovascular health and cancer risk, as well as lower risk of cardiovascular diseases, cancer, and death, according to a new review of 49 previously published papers. Angelo Capodici and colleagues present these findings in the open-access journal PLOS ONE on May 15, 2024.

Prior studies have linked certain diets with increased risk of cardiovascular disease and cancer. A diet that is poor in plant products and rich in meat, refined grains, sugar, and salt is associated with higher risk of death. Reducing consumption of animal-based products in favor of plant-based products has been suggested to lower the risk of cardiovascular disease and cancer. However, the overall benefits of such diets remain unclear.

To deepen understanding of the potential benefits of plant-based diets, Capodici and colleagues reviewed 48 papers published between January 2000 and June 2023 that themselves compiled evidence from multiple prior studies. Following an "umbrella" review approach, they extracted and analyzed data from the 48 papers on links between plant-based diets, cardiovascular health, and cancer risk.

Their analysis showed that, overall, vegetarian and vegan diets have a robust statistical association with better health status on a number of risk factors associated with cardiometabolic diseases, cancer, and mortality, such as blood pressure, management of blood sugar, and body mass index. Such diets are associated with reduced risk of ischemic heart disease, gastrointestinal and prostate cancer, and death from cardiovascular disease.

However, among pregnant women specifically, those with vegetarian diets faced no difference in their risk of gestational diabetes and hypertension compared to those on non-plant-based diets.

Overall, these findings suggest that plant-based diets are associated with significant health benefits. However, the researchers note, the statistical strength of this association is significantly limited by the many differences between past studies in terms of the specific diet regimens followed, patient demographics, study duration, and other factors. Moreover, some plant-based diets may introduce vitamin and mineral deficiencies for some people. Thus, the researchers caution against large-scale recommendation of plant-based diets until more research is completed.

The authors add: "Our study evaluates the different impacts of animal-free diets for cardiovascular health and cancer risk showing how a vegetarian diet can be beneficial to human health and be one of the effective preventive strategies for the two most impactful chronic diseases on human health in the 21st century."

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• Angelo Capodici, Gabriele Mocciaro, Davide Gori, Matthew J. Landry, Alice Masini, Francesco Sanmarchi, Matteo Fiore, Angela Andrea Coa, Gisele Castagna, Christopher D. Gardner, Federica Guaraldi. Cardiovascular health and cancer risk associated with plant based diets: An umbrella review . PLOS ONE , 2024; 19 (5): e0300711 DOI: 10.1371/journal.pone.0300711

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Bariatric Surgery Reduces Breast Cancer Incidence in a Prospective Trial

• 1 Division of Breast Surgery, Department of Surgery, Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
• Original Investigation Breast Cancer Risk After Bariatric Surgery and Influence of Insulin Levels Felipe M. Kristensson, MD; Johanna C. Andersson-Assarsson, PhD; Markku Peltonen, PhD; Peter Jacobson, MD, PhD; Sofie Ahlin, MD, PhD; Per-Arne Svensson, PhD; Kajsa Sjöholm, PhD; Lena M. S. Carlsson, MD, PhD; Magdalena Taube, PhD JAMA Surgery

In this issue of JAMA Surgery , Kristensson et al 1 build on their previous research using participants from the Swedish Obese Subjects Study (SOS), a prospective, controlled trial comparing bariatric surgery to usual care. The SOS investigators initially reported a decrease in cancer incidence after bariatric surgery in women, but not in men. 2 Subsequently, in the cohort of women participants, they reported that bariatric surgery reduced the incidence of female-specific cancers, particularly in those women who had hyperinsulinemia at baseline. 3 In this current study, women were followed up for a median of 23.9 years after bariatric surgery or usual care. The authors found a significantly lower incidence of breast cancer in the surgery group compared to the usual care group in premenopausal women and in women with elevated median insulin levels and insulin resistance at the time of enrollment. 1 This study is the first prospective study with long-term follow-up to report an association between bariatric surgery and a reduction in breast cancer incidence. While cancer incidence was not a prespecified end point and the SOS study was not randomized, a significant strength of the study is that both the surgery and usual care arm patients were eligible for bariatric surgery, which allowed for a more unbiased comparison of the 2 groups.

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Kulkarni SA , Sterbling HM. Bariatric Surgery Reduces Breast Cancer Incidence in a Prospective Trial. JAMA Surg. Published online May 15, 2024. doi:10.1001/jamasurg.2024.1158

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Chad hepatitis E outbreak: How the dangerous liver disease spreads and how it can be treated

by Kolawole Oluseyi Akande, The Conversation

The World Health Organization recently announced an outbreak of hepatitis E in the eastern Ouaddai province of Chad. Between January and April 2024, 2,093 suspected hepatitis E cases were reported from two health districts. The Conversation Africa asked Kolawole Oluseyi Akande, a consultant gastroenterologist and hepatologist, to explain the causes, symptoms, spread and treatment of hepatitis E.

What is hepatitis and how many types are there?

Hepatitis is an inflammation of the liver . It is the way the liver responds to various injuries or harmful agents.

Hepatitis is caused by a variety of infectious viruses and noninfectious agents , leading to a range of health problems, some of which can be fatal.

Common causes include viruses (viral hepatitis), excessive consumption of alcohol (alcohol hepatitis), excessive fat in the liver (steato-hepatitis), drugs and toxins (toxic hepatitis) and autoimmunity ( autoimmune hepatitis ).

There are also a number of types of the disease. The most common, especially in developing countries like Chad, are the viral hepatitides. There are five main viruses that cause viral hepatitides . They are hepatitis A, B, C, D and E viruses. They are not strains of the same virus but different viruses. The outbreak in Chad was of hepatitis E.

All the various types of hepatitis cause liver disease but differ in modes of transmission, severity of the illness, geographical distribution and prevention methods. An estimated 354 million people globally live with hepatitis B or C.

Globally , approximately 939 million (1 in 8) individuals have ever experienced hepatitis E infection. Fifteen million to 110 million individuals have recent or ongoing hepatitis E infection as at 2020. It is widespread with prevalence rates of 21.8%, 15.8%, 9.3%, 8.5% and 7.3% in Africa, Asia, Europe, North America and South America respectively. Its presentation ranges from asymptomatic to severe acute failure which can lead to death.

How does hepatitis E spread?

Of the eight genotypes of hepatitis E virus , four are known to affect humans.

Genotypes 1 and 2 are spread by faeco-oral routes, especially through drinking contaminated water. This is why these types of hepatitis E are common in underdeveloped countries of Asia and Africa with poor sanitation, poor hygiene, and lack of safe drinking water.

They are the types that can affect large numbers of people in epidemics. Genotypes 3 and 4 are spread through ingestion of contaminated meat, especially swine, goats and cattle, and sometimes through contamination of water by feces of animals.

So, these are diseases of animals that can spread to humans (zoonotic diseases) and therefore tend to affect people who deal with animals like farmers, butchers and veterinarians.

There is evidence that hepatitis E virus can be spread through blood transmission. A few developed countries , such as the Netherlands, United Kingdom, France and Japan, have incorporated hepatitis E RNA screening of blood donations before transfusion. The RNA screening is the most reliable way of detecting hepatitis E virus in the blood or stool.

What are the risks to humans?

Hepatitis E is a global health problem with about 20 million cases occurring annually, three million symptomatic cases and 60,000 deaths.

Hepatitis E can cause acute hepatitis without symptoms, or mildly symptomatic, or sometimes severely symptomatic illness. Pregnant women are more likely to experience severe illness. It could also be severe in people with already established liver diseases, the elderly, and those whose immunity is low (immunocompromised).

In a survey of 177 asymptomatic food handlers across 12 restaurants in Ibadan, south-west Nigeria, we found 9% had evidence of acute hepatitis E in their blood. Asymptomatic people with hepatitis E virus can transmit the virus if their blood is given to another person.

In pregnancy it can lead to severe disease or death of the mother and the baby. The mortality rate in pregnancy may be as high as 30% .

Symptoms of hepatitis include malaise, weakness, yellowness of the eyes, upper abdominal pain, dark urine and if there is liver failure, alteration in the level of consciousness and bleeding tendencies.

Hepatitis E is not distinguishable, based on symptoms and signs, from other forms of viral hepatitis . Hepatitis E is the most frequent cause of acute hepatitis globally. In certain circumstances, especially in organ transplant patients, hepatitis E can lead to chronic hepatitis (lasting for more than three months) and this can lead to liver cirrhosis. This is quite common in developed countries where there are many organ transplant patients who are on immunosuppressive medications.

Is it preventable?

Yes. What's needed is adequate personal hygiene, proper waste disposal systems and the provision of safe and clean water. Another way to prevent hepatitis E is to avoid uncooked or undercooked meat.

A study suggests that heating food to 71°C for 20 minutes could inactivate hepatitis E virus.

There is also a vaccine against hepatitis E available in China , but this is not widespread yet.

How is it controlled?

Treatment of hepatitis E when symptomatic includes bed rest and avoidance of drugs and substances that can further damage the liver.

Ribavirin and interferon alpha are drugs that are sometimes used, although not for pregnant women .

Those with acute liver failure or liver cirrhosis may need a liver transplant.

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