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Human and animal disease are often caused by viruses or bacteria. Over the past two hundred or so years, vaccines have eradicated some of these diseases. Others have returned to haunt humans with new and ever-mutating strains. Communicable diseases may spread in different ways: through blood, air, feces/urine, food, or water. The World Health Organization (WHO) and the Center for Disease Control (CDC) keep constant watch over the most potentially dangerous diseases and the most likely threats to various world populations.

Lyme disease, Ebola and malaria all developed in animals before making the leap to infect humans. Predicting when such a 'zoonotic' disease will spark an outbreak remains difficult, but a new study suggests that artificial intelligence could give these efforts a boost. A computer model that incorporates machine learning can pinpoint, with 90% accuracy, rodent species that are known to harbour pathogens that can spread to humans, researchers report this week in the Proceedings of the National Academy of Sciences1. The model also identified more than 150 species that are likely to be disease reservoirs but have yet to be confirmed as such.

This lab will let you explore various diseases: Kold, a caricature of the common cold; Impfluenza, which resembles influenza; Neasles, with the high transmission rate of measles; and Red Death, a fast-spreading epidemic with a high mortality rate. What factors come into play in the spread of these diseases? And what can we do to counter them?

"This case study uses a PowerPoint presentation to guide students through two activities designed to teach them about the basics of coronavirus diagnosis and transmission. The first activity involves a set of five "clicker questions" that students answer using either a personal response system, online polling application, or show of hands as they consider symptoms and test results of a hypothetical patient. The second activity is an outbreak simulation in which students consider the spread of a pathogen in various geographical settings and from different perspectives. Students work together to draft a list of precautions that could be taken to limit the spread of the disease and minimize healthy individuals' risk of contracting it. The simulation is designed for a biology lesson pertaining to outbreaks. Although coronavirus is used as the model, the concepts of disease transmission and prevention covered in this case are relevant to many diseases."

This case study centers on an active teaching game that simulates a cholera outbreak among five villages along a river, similar to the Haitian outbreak of 2010. By enacting the behaviors of fictional villagers, students learn how trade, travel, sanitation practices and geographic location contribute to the spread of diarrheal disease. Documenting various contamination events of village water supplies allows students to trace the progression of the disease and illustrates how adequate sanitation facilities provide protection against the bacteria Vibrio cholera. Originally designed for an undergraduate upper-division biology course focusing on the epidemiology of diseases, the simulation is also appropriate for microbiology and public health courses, as well as lower division undergraduate biology courses and high school. Biology or epidemiology components of the case study can be highlighted depending on the emphasis of the course being taught. The game can be completed within a 45- to 60-minute class period. Playing cards are available from the Supplemental Materials tab; detailed instructions are found in the teaching notes.

The world is becoming more urban every day, and the process has been ongoing since the industrial revolution in the 18th century. The United Nations now estimates that 3.9 billion people live in urban centres. The rapid influx of residents is however not universal and the developed countries are already urban, but the big rise in urban population in the next 30 years is expected to be in Asia and Africa. Urbanization leads to many challenges for global health and the epidemiology of infectious diseases. New megacities can be incubators for new epidemics, and zoonotic diseases can spread in a more rapid manner and become worldwide threats. Adequate city planning and surveillance can be powerful tools to improve the global health and decrease the burden of communicable diseases.

The CDC released travel health notices Tuesday that named two more places in which the disease has spread via mosquito bites: The US Virgin Islands and the Dominican Republic.  The Zika virus is primarily transmitted by Aedes aegypti, the type of mosquito responsible for spreading dengue, yellow fever, and a whole host of other tropical infectious diseases. Originally identified in 1947 in Uganda, Zika was relatively unknown until 2007, when there was an outbreak of the virus in Micronesia. The mosquitoes pick up the virus from infected people, according to the CDC. 

Scientists and healthcare professionals initially exhibited little concern over the Zika virus even after evidence of human infection was first identified in 1952; Zika appeared to be both rare and unassociated with morbidity or mortality. Around 2015 all of this changed as journalists, scientists, public health officials, and laypeople scrambled to learn about its varied modes of transmission and devastating consequences (e.g., birth defects and autoimmune disorders). Although research continues to rapidly evolve, this case study directs students to reliable scientific sources (e.g., Centers for Disease Control and World Health Organization) that will likely continue to provide the most current information in order to explore questions such as: Where did the virus come from? How does it spread? What can we do to prevent it? Students will also consider the public health challenges and possible solutions associated with emerging infectious diseases. The case was originally written for an upper-level biology or public health course in which students already have some basic background knowledge regarding viruses, vaccines, and infectious disease.

The scientists are from the Centers for Disease Control and Prevention, and they have embarked on this watery journey to solve a decades-old mystery about a rare and fatal disease: monkeypox. A cousin to the deadly smallpox virus, the monkeypox virus initially infects people through contact with wild animals and can then spread from person to person. The disease produces fever and a rash that often turns into painful lesions that can feel like cigarette burns. It kills up to 1 in 10 of its victims, similar to pneumonic plague, and is particularly dangerous in children. Monkeypox is on the U.S. government list of pathogens such as anthrax and Ebola with the greatest potential to threaten human health. There is no cure.

This case study is based on the 2014 Ebola epidemic that spread to multiple highly populated countries in West Africa, making it the largest and most devastating outbreak in the history of the virus. The storyline, inspired by a compilation of factual information, unfolds through a fictional narrative wherein students play the role of an infectious disease specialist in training to learn about the techniques used in the detection, diagnosis, and management of Ebola virus outbreaks. The story is presented as an interrupted "clicker case" that combines problem-based case teaching methods with simulated biological laboratory inquiry through the use of Case It, a free molecular biology software, along with the NCBI's online bioinformatics tools and databases. Students work in groups to collaboratively explore various biological and social aspects of this infectious disease outbreak. This case was developed for senior students at the secondary level and can be modified for use in an introductory biology, microbiology, or epidemiology course at the undergraduate level.

The war against malaria has a new ally: a controversial technology for spreading genes throughout a population of animals. Researchers report today that they have harnessed a so-called gene drive to efficiently endow mosquitoes with genes that should make them immune to the malaria parasite-and unable to spread it. On its own, gene drive won't get rid of malaria, but if successfully applied in the wild the method could help wipe out the disease, at least in some corners of the world. The approach "can bring us to zero [cases]," says Nora Besansky, a geneticist at the University of Notre Dame in South Bend, Indiana, who specializes in malaria-carrying mosquitoes. "The mosquitos do their own work [and] reach places we can't afford to go or get to."

Reporting on a small preliminary study, Johns Hopkins researchers say a simple blood test based on detection of tiny epigenetic alterations may reveal the earliest signs of pancreatic cancer, a disease that is nearly always fatal because it isn't usually discovered until it has spread to other parts of the body.

The United States is now experiencing what promises to be one of the worst outbreaks of measles since the virus was declared eliminated from the country in 2000.  It began in early January at Disneyland Resort in Anaheim, California, and has since spread to 14 states and infected 84 people, according to the U.S. Centers for Disease Control and Prevention (CDC). Measles, caused by a paramyxovirus from the genus Morbillivirus, is one of the most contagious diseases in the world, infecting more than 90% of susceptible hosts that come in contact with an afflicted individual. In the absence of widespread vaccination, the average person with measles will infect an average of 12 to 18 other people; in contrast, Ebola is typically transmitted to 1.5 to 2.5 people.

HIV is a disease of the gut, a concept that's easy to lose sight of with all the attention paid to sexual transmission and blood measurements of the virus and the CD4+ T cells it infects and kills. But the bottom line is that about two thirds of all T cells reside in the lymphoid tissue of the gut, where the virus spreads after exposure, even before it shows up in blood.

This activity guides the analysis of a published scientific figure from a study that modeled the impact of an infectious fungal disease on a bat population. In 2006, a disease called white-nose syndrome (WNS) began wiping out bat populations in North America. Because many of these bats eat insect pests, the spread of WNS may devastate ecosystems and increase pest control costs. In this study, scientists mathematically modeled the effects of WNS to estimate extinction probabilities for the little brown bat (Myotis lucifugus) population in the northeastern United States. This figure shows these probabilities projected for five annual rates of population decline. Each projection is simulated up to 100 years after WNS emerged in the population. The "Educator Materials" document includes a captioned figure, background information, graph interpretation, and discussion questions. The "Student Handout" includes a captioned figure and background information.

Around the world, disease-carrying mosquitoes are advancing at speed, taking viruses such as dengue and Zika, plus a host of lesser-known ills such as chikungunya and St. Louis encephalitis, into new territories from Europe to the Pacific. "The concern is that we have these species spreading everywhere. Today the focus is on Zika but they can carry many different viruses and pathogens," said Anna-Bella Failloux, head of the department that tracks mosquito viruses at France's Institut Pasteur.

For 10,000 years, humanity suffered from the scourge of smallpox. The virus killed almost a third of its victims within two weeks and left survivors horribly scarred. But Simona Zompi commends the brave souls - a Buddhist nun, a boy, a cow, a dairymaid and physician Edward Jenner - who first stopped the spread of this disastrous disease, to make us smallpox-free today.

Which pathogens play a major role in causing infection? Just recently, the Robert Koch-Institute prepared a list of 127 pathogens by ranking them in terms of frequency, spread and burden of disease.   Considering this prioritisation, we extended our search tool by bacteria, viruses and fungi accordingly. In the list, you will find both the clinically relevant pathogens and the spectrum of effect necessary for disinfectants to inactivate them.

NPR's Jason Beaubien explains cholera, a deadly disease spread through water contaminated with sewage, in under two minutes.

2:25 video  Scientists have recently discovered that the limbs of some sea stars have been turning into goo, and populations are dying off! Why is this happening, and will this hurt their ecosystem? Join Laci as discusses how this disease is spreading, and why it have some negative consequences.