Microorganisms: Infectious Disease and Ecology

Blog entries about bacteria, viruses, fungi and other microorganisms.

Mind Control, Mutilation and Death. The Fungal Fate That Lurks in Waiting for Emerging Periodical Cicadas

Posted on by Kelly Grooms

For the first time since Thomas Jefferson was president, broods of 13- and 17-year periodical cicadas are emerging from the ground at the same time. The fate that awaits some of these periodic cicadas—a fungal infection that hijacks their behavior and destroys their genitalia — sounds like the script of a bad zombie horror film. The culprit (or villain) is the entomopathogenic fungus Massospora cicadina.  

An adult red eyed 17-year periodical cicada sits on a leaf

While most entomopathogens kill their host before releasing their infectious spores, M. cicadina is one of the few species that increase spore dispersal by hijacking their host’s behavior and keeping them alive while sporulating (1). The manner it uses to do this is both gruesome and fascinating. If you can stomach some details of insect sex and dismemberment, read on.

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Measles and Immunosuppression—When Getting Well Means You Can Still Get Sick

Posted on by Kelly Grooms
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In 2000 measles was officially declared eliminated in the United States (1), meaning there had been no disease transmission for over 12 months. Unfortunately it was not gone for good. So far in 2024 there have been 8 outbreaks and 131 cases. Ninety of these case (69%) are associated with an outbreak and seventy (53%) have resulted in hospitalization (as of May 2, 2024; 2).  

Help in Limiting a Dangerous Childhood Disease

Before the development of a vaccine in the 1960s, measles was practically a childhood rite of passage. This common childhood disease is not without teeth however. One out of every 20 children with measles develops pneumonia, 1 out of every 1,000 develops encephalitis (swelling of the brain), and 1 to 3 of every 1,000 dies from respiratory and neurological complications (3). Between the years of 1958 and 1962, the US averaged 503,282 reported cases of measles (4). The first measles vaccine was licensed in the U.S. by John Enders in 1963, and not surprisingly, after the measles vaccine became widely used, the number of cases of measles plummeted. By 1970, there were under 1,000 cases (2).

Decreased Childhood Mortality from Other Infectious Diseases—An Unexpected Benefit

What was surprising was that with the disappearance of this childhood disease, the number of childhood deaths from all infectious diseases dropped dramatically. As vaccination programs were instituted in England and parts of Europe, the same phenomenon was observed. Reduction or elimination of measles-related illness and death alone can’t explain the size of the decrease in childhood mortality. Although measles infection is associated with suppression of the immune system that will make the host vulnerable to other infections, these side effects were assumed to be short lived. In reality, the drop in mortality from infectious diseases following vaccination for measles lasted for years, not months (5).

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Automated Sampling and Detection of ToBRFV: An Emerging Tomato Virus 

Posted on by Michele Arduengo
Tomatoes affected by a virus, showing the yellow and brown spots characteristic of ToBRFV.

In the Spring of 2015, greenhouse tomato plants grown in Jordan presented with a mosaic pattern of light and dark green patches on leaves, narrowing leaves, and yellow- and brown-spotted fruit (Salem et al. 2015). The pathogen was identified as a novel plant virus, the tomato brown rugose fruit virus (ToBRFV), and the original outbreak was traced back to the fall of 2014 to Israel (Luria et al. 2017).  This newly emerging virus can infect tomato and pepper plants at any stage of development and greatly affect crop yield and quality. Furthermore, the virus spreads rapidly by mechanical contact but can also be spread over long distances by contaminated seeds (Caruso et al. 2022), and as of 2022 it had been detected in 35 countries across four continents (Zhang et al. 2022).  Compounding its transmissibility, is the ability of the virus escape plant genetic resistance to viral infection (Zhang et al. 2022). There are seven host plants for the virus, including some common grasses and weeds, which could act as a reservoir for the virus, even if it is eliminated from commercial crops. Some researchers consider ToBRFV to be the most serious threat to tomato production in the world. 

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How Avian Influenza Crosses Species

Posted on by Johanna Lee

Avian influenza, commonly known as bird flu, has become an increasingly severe public health issue. According to the CDC, the frequency of avian influenza outbreaks and diversity of virus subtypes have increased significantly in the past decade. In 2022, there were reports of sporadic H5 virus infections in mammals across several U.S. states, Canada, and other countries. Affected animals included fox kits, bobcats, coyote pups, raccoons, skunks, mink, and even seals. Human cases of H5N6 and other subtypes following poultry exposures were reported in China, with several cases resulting in severe or critical illness and death.

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How do Self-Amplifying RNA Vaccines Work?

Posted on by Jordan Nutting

In late November 2023, regulatory authorities in Japan approved a new SARS-CoV-2 vaccine. Unlike earlier messenger RNA (mRNA) vaccines used to protect against COVID-19, this one relies on a technology called self-amplifying mRNA, or saRNA. Though researchers have long pursued saRNA-based vaccines, this represents the first full approval for the technology in humans and marks an exciting advance in the ongoing development of mRNA vaccines.

Continue reading for an overview of how saRNA vaccines work and some of their advantages relative to standard mRNA vaccines.

A syringe withdraws clear liquid from a sealed glass vial.
 A new type of COVID-19 mRNA vaccine, a self-amplifying RNA vaccine, was recently approved in Japan.
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Cyanobacteria Identified as Cause of Elephant Mass Mortality Event

Posted on by Kelly Grooms

The largest contiguous population of elephants in Africa lives in the Kavango-Zambezi Trans Frontier Conservation Area (KAZA TFCA) which encompasses parts of Botswana Zimbabwe, Zambia, Angola and Namibia. Within KAZA, nearly 90% of the elephant population is concentrated in Botswana (58%) and Zimbabwe (29%). In June of 2020, over 300 elephants were found dead in Botswana under mysterious circumstances. Less than two months later—in a span of only 27 days—34 more elephant deaths were reported in neighboring Zimbabwe. The news of these mass mortality events was both notable and concerning given the importance of the KAZA elephant metapopulation to species conservation.

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For Frogs, Surviving the Heat Could Come Down to What Is in Their Gut

Posted on by Kelly Grooms

Amphibians are the most threatened vertebrate class worldwide. Because they lack the ability to regulate their own temperature and moisture levels, climate change is playing a significant role in this growing peril (1). Climate change impacts amphibian survival in several ways. In addition to habitat loss, growing drought conditions make maintaining body moisture levels challenging and warming temperatures restrict activity periods needed for reproduction as well as increasing the risk of heat stress.

Heat tolerance varies by species, and understanding what influences these differences could help predict species survival. The gut microbiota is known to affect a wide range of functions in host animals, and recently studies have begun to investigate its role in host thermal tolerance (2).

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Promega qPCR Grant Series #3: Immunotherapy Researcher, Dr. Sabrina Alves dos Reis 

Posted on by Anna Bennett
Professional headshot image of Dr. Sabrina Alves dos Reis, subject of the blog post
Sabrina Alves dos Reis

In our third and final installment of the Promega qPCR Grant Recipient blog series, we highlight Dr. Sabrina Alves dos Reis, a trained immunotherapy researcher. Her work has focused on developing tools for more accessible cancer therapies using CAR-T cells. Here, we explore Dr. Alves dos Reis’ academic and scientific journeys, highlight influential mentorship and foreshadow her plans for the Promega qPCR grant funds. 

Dr. Alves dos Reis’ career began with a strong affinity for biology. As an undergraduate student, she pursued a degree in biological science, where she developed a foundational understanding for designing and developing research projects. As her passion for science heightened, she decided to continue her journey in science, culminating in a PhD at the Fundação Oswaldo Cruz Institute in Rio de Janeiro, Brazil. Her research projects focused on the unexplored territory of adipose tissue as a site for Mycobacterium leprae—or leprosy bacillus—infection. She mentioned that this work piqued her curiosity for improving immunotherapies and laid the foundation for her future in cancer research.  

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Clovibactin: A Revolutionary Antibiotic with No Resistance

Posted on by Riley Bell
Pills

Antimicrobial resistance (AMR) threatens the effective prevention and treatment of an ever-increasing range of infections. It’s a leading mortality factor worldwide, but the newly discovered antibiotic, clovibactin, may offer a pivotal solution. It effectively kills drug-resistant bacterial pathogens without detectable resistance—even multidrug-resistant “superbugs.”

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On-site, In-house Environmental Monitoring to Obtain Species-Level Microbial Identification

Posted on by Michele Arduengo

Loss of life and serious illness from contamination of manufactured products that are consumed as food or used in medical procedures illustrate the need to prevent contamination events rather than merely detect them after the fact.  High-profile news stories have described contamination events in compounding pharmacies (1), food processing and packaging plants (2) and medical device manufacturers (3). Although contamination in manufacturing settings can be physical, chemical, or biological, this article will focus environmental monitoring to determine the quality of a manufacturing facility with respect to microbial contamination.

Scientist in pharmaceutical manufacturing facility performing environmental monitoring.

To ensure that the products they produce and package are manufactured in a high-quality, contaminant-free environment, many industries are required to establish routine environmental monitoring programs. Samples are collected from all potential sources of contamination in the production environment including air, surfaces, water supplies and people. Routine monitoring is essential to detect trends such as increases in potential pathogens over time or the appearance of new species that have not been seen before so that contamination events can be prevented.

Because environmental monitoring requires identification to the level of the species, most environmental monitoring programs will collect samples and then send them off to a facility to be sequenced for genomic identification of any microbial species. Such genotypic analysis involves DNA sequencing of ribosomal RNA (rRNA) genes to determine the taxonomic classification of bacteria and fungi. In this method, informative sections of the rRNA genes are amplified by PCR; the PCR products sequenced; the sequence is compared to reference libraries; and the results interpreted to make a species-level identification for a given microbial isolate.

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