West Nile Virus

West Nile Virus is an arbovirus of the flavivirus genus which is able to infect a range of vertebrate hosts such as humans, birds and horses1. Its history in the eastern hemisphere dates back to 1937 and is carried by Culex species of mosquitoes, which can infect mammals via bites1. This arbovirus was introduced to the Western hemisphere in 1999 in New York City (NYC) where it infected both birds and humans. While public health officials confirmed 61 human cases across NYC, door to door serostudies conducted throughout the next year estimated the infection rate to be up to 2.6% in the Queens area. This infection rate would estimate that there were closer to 8200 cases in Queens, most of which went undiagnosed due to asymptomatic infections1.

Many public health officials believed the introduction of WNV in the U.S. would spread slowly outside of NYC as Culex mosquitoes, the carrier of WNV, increased their range. However, in 2002, it was shown that WNV infected mosquitoes had rapidly disseminated when an outbreak of WNV was identified in 28 states with 4,156 confirmed cases of WNV2,3. Then, in 2003, the Culex mosquitoes carrying WNV were confirmed in all Eastern and Midwest states (sans Maine) and infected 9,862 individuals in the U.S. alone1,2 (Figure 1).

west nile f1 (2)

While mild infection of WNV and other arboviruses are similar to a seasonal cold in clinical symptoms, approximately 1 in 150 individuals will develop neuroinvasive disease which can lead to convulsions, organ failure and death3,4. Neuroinvasive disease became a reportable illness in the U.S. in 2001, while non-neuroinvasive disease became reportable in 2004, with all states having their own surveillance systems which then report to the national network called arboNET, which is maintained by the Centers for Disease Control and Prevention (CDC)4. Furthermore, recent research suggests that many arboviruses can lead to neurological deficits and diseases such as Guillain-Barre syndrome or congenital diseases such as microcephaly during pregnancy later on in life after initial infection4.

Mitigation of WNV is of concern to health officials due to the risk of developing the severe symptoms which can lead to death and the compounded concern of neurological deficits resulting from infection. Arboviruses also tend to have a cyclical infection cycle where a specific virus will have an increased number of infections during one year, level out over the next 8-10 years and then peak again2,4.

There is no treatment for West Nile and hospitals and providers generally provide care to cover the symptoms. Similarly, no vaccines in clinical trials been successful enough to be mass-produced and distributed4,5. With no other treatment options and the cyclical cycle of infection-causing different arboviruses to peak in different years, a non-disease specific way of controlling the vector (mosquito) populations is currently the supported means of controlling arbovirus infection rates (Figure 2). Both passive and active forms of vector control will be evaluated for efficiency over the last decade, with a recommendation towards using genetically modified mosquitoes within integrated vector management (IVM) approach as a long term means of vector control.

Epidemiology

Since its introduction to NYC in 1999, WNV has become the leading arbovirus infection and encephalitis in the U.S. Only about 1 in 5 individuals with an infection will have symptoms which include what is defined as an acute system febrile illness, the other 4 out of 5 individuals will be asymptomatic4. The most common symptoms seen with systemic febrile illness are a headache, arthralgia, rash, and gastrointestinal disturbances. In 1 out of 150 cases, individuals will develop neuroinvasive diseases such as meningoencephalitis, meningitis, encephalitis or acute flaccid paralysis (AFP), any one of which can be life threatening3,4.

Like many illnesses, WNV infection can affect vulnerable populations differently and a paper by CDC in 2010 calculated the rates of infection for different populations after analyzing the 28,961 cases that met clinical and laboratory criteria for WNV infection between 1999-2008. Of these cases, 17,139 (approximately 59%) were defined as non-neuroinvasive and 11,822 (41%) were defined as neuroinvasive (Table 1).

f2 (2)

Out of the 17,139 cases reported of non-neuroinvasive, males accounted for 8,972 approximately, 52% of the confirmed cases (Table 1). Similarly, for neuroinvasive cases, males accounted for 6,887 cases out of 11,822 reported cases (Table 1). Neuroinvasive disease and non-neuroinvasive affected older populations at a higher rate, with the median age being 57 years old and 47 years old, respectively. In Neuroinvasive, nearly 46% of cases were 60 years old or above, while 45% of non-neuroinvasive were between 40-59 years old. For both forms of the disease, between 88-95% of those affected were Caucasian with 82-90% of cases being non-Hispanic (Table 1).

Out of the 8925 cases with hospital data, the non-neuroinvasive cases had a hospitalization rate of 20.6/1000 and a fatality rate of 0.96/1000. Of the fatal cases, being above 70 years old increased your risk as 85 of 86 fatal cases were above 70. Neuroinvasive has a higher rate of hospitalization going from 20.6/1000 in non-neuroinvasive to 86/1000 in neuroinvasive1,4. Neuroinvasive cases also results in a higher fatality rate going from 47/1000 in non-neuroinvasive to 178/1000 in neuroinvasive. The mean annual incidence of neuroinvasive cases rose from 5/1000 for those younger than 10 to 135/1000 for those above 70. This trend continues for gender differences and age with a mean incidence of 48/1000 in men and 33/1000 for women below 70 years old but increasing to 200/1000 in men and 89/1000 for women above 70 years old1,4.

West Nile Virus is an arbovirus which is transmitted by mosquitoes through mosquito bites. For both forms of the disease, between 91-94% of cases occurred between July and September, the peak mosquito season4. As you can see in Figure 1, WNV disseminated across the U.S. within 6 years, and by 2006 is found in every state in the continental U.S. except for Maine. Similarly, all arboviruses follow a cyclical pattern of infection where one virus will surge during one year while the rest maintain a low infection rate and then the surging virus will level out for 8-10 years while other viruses surge periodically. Then after 8-10 the first virus will surge again; for West Nile virus you see this trend in 2002-2003 when it first enters the United States, levels out between 2003-2011 and then surges again in 2012 (Figure 2).

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References

  1. Assessing Capacity for Surveillance, Prevention, and Control of West Nile Virus Infection—United States, 1999 and 2004. Jama. 2006;295(15):1765.
  2. Provisional Surveillance Summary of the West Nile Virus Epidemic—United States, January–November 2002. Jama. 2003;289(3):293.
  3. Roehrig J. West Nile Virus in the United States — A Historical Perspective. Viruses. 2013 Oct;5(12):3088–108.
  4. Patel H, Sander B, Nelder MP. Long-term sequelae of West Nile virus-related illness: a systematic review. The Lancet Infectious Diseases. 2015;15(8):951–9.
  5. Bellini R, Zeller H, Bortel WV. A review of the vector management methods to prevent and control outbreaks of West Nile virus infection and the challenge for Europe. Parasites & Vectors. 2014;7(1):323.
  6. Benelli G. Research in mosquito control: current challenges for a brighter future. Parasitology Research. 2015;114(8):2801–5.
  7. Wilke ABB, Marrelli MT. Paratransgenesis: a promising new strategy for mosquito vector control. Parasites & Vectors. 2015;8(1).
  8. Dodson BL, Hughes GL, Paul O, Matacchiero AC, Kramer LD, Rasgon JL. Wolbachia Enhances West Nile Virus (WNV) Infection in the Mosquito Culex tarsalis. PLoS Neglected Tropical Diseases. 2014 Oct;8(7).
  9. Fradin MS, Day JF. Comparative Efficacy of Insect Repellents against Mosquito Bites. New England Journal of Medicine. 2002 Apr;347(1):13–8.
  10. Knox TB, Juma EO, Ochomo EO, Jamet HP, Ndungo L, Chege P, et al. An online tool for mapping insecticide resistance in major Anopheles vectors of human malaria parasites and review of resistance status for the Afrotropical region. Parasites & Vectors. 2014;7(1):76.
  11. Hamer GL, Anderson TK, Donovan DJ, Brawn JD, Krebs BL, Gardner AM, et al. Dispersal of Adult Culex Mosquitoes in an Urban West Nile Virus Hotspot: A Mark-Capture Study Incorporating Stable Isotope Enrichment of Natural Larval Habitats. PLoS Neglected Tropical Diseases. 2014;8(3).
  12. Jost CA, Pierson TC. Antibody-Mediated Neutralization of West Nile Virus: Factors that Govern Neutralization Potency. West Nile Encephalitis Virus Infection. 2009;219–47.

 

That squirming little thing… is a ParaWHAT? Microbe Monday #4

Paramecium- the most well-known protists in history.

Domain: Eukaryota
Phylum: Ciliophora
Class: Oligohymenophorea
Order: Peniculida
Family: Parameciidae
Genus: Paramecium

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What is a Paramecium?

Paramecium are the most commonly studied organism when learning about single celled microorganisms. First seen in the 17th century by early French and Dutch microscopists, a paramecium is well-known for its ability to rapidly conjugate and divide, this species is considered a model organism for studying biological processes.

Structure and Environment conditions

Paramecium_diagram.svg.png

As with all Eukaryotes, paramecia have a very organized cell structure with organelles such as a cytoplasm, vacuoles, and mitochondria. However, paramecia have also developed unique structures such as micro and macro nucleus, cilia and cytoprocts. Cilia are small tendril like hairs protruding from the pellicle (membrane) which aid in movement and eating.

Paramecia are heterotrophs, meaning that they eat other microorganisms such as bacteria, algae and other small organisms. Paramecia are roughly 50-350 micrometers in size and are easily seen through a standard light microscope. Paramecia are found in almost every water source- ponds, lakes, oceans and even fossil aquifers!

Paramecium

Facts about Paramecium 

  • Its micro and macro nuclei have separate functions- without the macronucleus, the cell cannot survive, but without the micronucleus, the call cannot reproduce.
  • These organisms can reproduce through binary fission (asexual), conugation (sexual) or even through endomixis, a form of self-fertilization
  • Can move up to 12x their body length every second
  • These organisms have no heart, brain, or eyes
  • Have been known to form symbiotic relationships with other animals
  • Recent research suggests that even without a nervous system, paramecia are able to learn and may have memory.
  • A single paramecium macronucleus can hold up to 800 chromosomes
  • Nearly half of it’s energy is used for motility
  • New Species of paramecia are being discovered even now!

References

Alipour, A., Dorvash, M., Yeganeh, Y., Hatam, G., & Seradj, S. H. (2017). Possible Molecular Mechanisms for Paramecium Learning. Journal of Advanced Medical Sciences and Applied Technologies, 3(1), 39-46.

Kapusta, A., Matsuda, A., Marmignon, A., Ku, M., Silve, A., Meyer, E., . . . Betermier, M. (2011). Highly precise and deleopmentally prongrammed genome assembly in Paramecium requires ligase IV-dependent end joining. PLoS Genetics, 7. Retrieved from http://www.plosgenetics.org/article/info%3Adoi%2F10.1371%2Fjournal.pgen.1002049

Krenek, S., Berendonk, T. U., & Fokin, S. I. (2015). New Paramecium (Ciliophora, Oligohymenophorea) congeners shape our view on its biodiversity. Organisms Diversity & Evolution, 15(2), 215-233.

 

 

Rabies Virus- Contagion between species. Monday Microbe #3

Rabies is one of the most well known zoonotic diseases in the world, and is transmissible between a wide range of animals from dogs, cats, bats, etc. and can infect any mammal.

Group: Group V ((−)ssRNA)
Order: Mononegavirales
Family: Rhabdoviridae
Genus: Lyssavirus
Species: Rabies lyssavirus

Image result for rabies virus

History:

Rabies was first recorded way back in the Mesopotamian Empire in 2000 B.C. In this culture, if an owner with a rabid dog did not take proper precautions against the dog biting others they would be fined. Rabies came to the new world in 1769 starting with a case in Boston. The majority of cases, 99%, are transferred between infected dogs and humans through bites, specifically the saliva. Rabies is considered one of the most concerning diseases of history and modem time. In 1885 a vaccine was developed in France by Louis Pasteur and Emile Roux for humans.

Image result for rabies

Facts about Rabies:

  • One of the worst parts about rabies if its prevalence throughout the world and ability to rapidly disseminate.
  • Rabies is present on all continents other than Antarctica
  • Almost 99% fatal for human already showing symptoms or humans who are un-vaccinated
  • Vaccination within 6 days of infections has been seen to have a 100% success rate for survival.
  • In 2010, 26,000 people diseased from rabies within the world. This is a significant decrease from the 54,000 deaths in 1990.
  • Well-known for its neurotropic effects- infecting nerve cells and altering human behaviors by shutting down the nervous system
  • First signs and symptoms of the flu such as fever, headache and dizziness, but can progress to confusion, anxiety and agitation.
  • Many people who are infected completely depersonalize in the later stages, reverting to pure “rage” personalities, attacking, biting scratching people and foaming at the mouth.
  • Rabies infection is the main disease cited in sci-fi and fantasy for “zombie-like” behaviors and many story lines utilize signs and symptoms similar to rabies as zombie indicators. So… the zombie apocalypse is coming!
  • Image result for zombie apocalypse

It’s a bird! It’s a plane! Wait no… it’s plague. Microbe Monday #2

Yersinia pestis is one of the most infamous microorganisms in the world- known commonly by the disease it causes: plague.

History of Yersinia pestis

The plague is first recorded during the Byzantine Empire during the reign of Justinian I, during 541 A.D. and continued to outbreak over the next 200 years, leaving over 25 million people dead (Rosen, 2007). Most commonly known for sweeping through the Old World during the Middle Ages and known as “The Black Death”, plague is on of the scariest infections in history. Starting in China during the 1300’s, this outbreak spread across trade routes and decimated an estimated 60% of all European populations (Benedictow, 2008). More recently, during the tail end of the 1800’s, plague was carried by ship routes throughout the world and had a 10 million mortality. The disease is carried by small animals such as rats, mice and squirrels, and jumps to humans through bites from fleas. The availability of small animal hosts quickly enables the transmission to a host of populations through carrier-mediated transmission.

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Facts about Yersinia pestis and Plague

  • There are three types of plague
    • Bubonic– characterized by sudden onset of fever headache, chills with tender lymph nodes. Results from the bite of a flea and localized to the nearest lymph nodes. If not treated, can spread to the rest of the body.
    • Septicemic– symptoms include fever, chills, abdominal pain, shock and bleeding into skin and organs. Skin and surrounding tissue may become necrotic (dead) and turn black. Transmissible from a flea bite or handling infected animals.
    • Pneumonic– symptoms include fever, chills, weakness and a rapid onset of pneumonia with secondary symptoms of chest pain, coughing and bloody mucous. Transmissible through inhaling infectious droplets, or from untreated bubonic or septicemic infections.
  • Can be treated with modern day antibiotics
  • Majority of modern day infections are confined to Sub-Saharan Africa or Madagascar, but cases have been seen in the United States (Arizona Included!), Europe, and IndiaPlague occurs on all continents except Europe and Australia. Central and east Africa have the most reported plague for the years 2000-2009.  Additional clusters of cases during this time period occurred in northern Africa, central Asia, southeast Asia, China, India, Madagascar, Peru, and the United States.Human plague cases in the United States, 1970-2012. All naturally occurring cases of human plague occur in the western United States, with a majority of cases clustering in northern New Mexico and Arizona and southern Colorado.
  • Plague vaccines were available, but were decommissioned. Currently, there are several different kinds of vaccines being developed but none available for use!
  • Plague is considered to be one of the first uses of bioterrorism- many invading armies would catapult bodies infected with plague into cities to kill the opposition.
  • Estimates of the plague say it has a mortality rate of 90-95%
  • Some historians attribute social upsets to the plague such as the Fall of Rome, the beginnings of the Renaissance and lost of influence of the Catholic Church leading to Protestantism.

References

Benedictow, Ole J. 2004. The Black Death 1346-1353: The Complete History. Woodbridge: Boydell Press.

Centers for Disease Control and Prevention. 2015. Yersinia Pestis. National Center for Emerging and Zoonotic Infectious Diseases (NCEZID)Division of Vector-Borne Diseases (DVBD)

Khan, I. A. (2004). Plague: the dreadful visitation occupying the human mind for centuries. Transactions of the Royal Society of Tropical Medicine and Hygiene, 98(5), 270-277.

Rosen, William (2007), Justinian’s Flea: Plague, Empire, and the Birth of Europe. Viking Adult; pg 3; ISBN 978-0-670-03855-8.

Microbe Monday #1

Welcome all to a new weekly posting from A Microbial World! Each week we will be discussing a new microorganism and how it impacts the world!

This week, we’re going to talk about one of my personal favorites- commonly called Water Bears or Moss Piglets (my favorite nomenclature)- Tardigrades! These cute little things look like this:

What are Tardigrades?

Kingdom: Animalia
Subkingdom: Bilateria
Infrakingdom: Protostomia
Superphylum: Ecdysozoa
Phylum: Tardigrada

Tardigrades were first discovered in 1773 by a German Pastor by the name of J.A.E. Goeze. Tardigrades are approximately 0.05 mm- 1.2 mm in length, with segmented bodies and 8 legs. They can reproduce via asexual reproduction and sexual reproduction and lay 1 to 30 eggs each cycle. Their diets can consist of the fluids of plants, animals and bacteria; they can eat Amoebas, nematodes and even other Tardigrades!

Why are they unique?

  • There are over 1,000 species of Tardigrades on earth
  • They live in extreme conditions from -330 to 300 degrees Fahrenheit, pressures up to 6 times the pressure of the deepest parts of the ocean, radiation and  even in the vacuum of space!
  • Tardigrades can be frozen and thawed without dying
  • They utilize a process called cryptobiosis where all metabolic processes come to a complete standstill.
  • They utilize a tiny layer of water around their bodies to keep hydrated and moving- they actually swim in their aqueous environments. When exposed to extremely dry conditions, they lose this layer and curl up into a ball-like shape called a Tun
  • Most species live in freshwater or semi-aqueous environments, however a few species live in salt water.
  • these little creatures are virtually indestructible and some theorize they have survived 5 mass extinctions over the last 500 million years.

Zika in Arizona!

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The first case of Zika Virus has been confirmed in Maricopa County as of today by The Maricopa County Department of Public Health. The woman had traveled to Zika affected area and returned home to Arizona where she started having symptoms. However, Public health officials believe that there is little chance of the virus spreading or becoming an epidemic here in Arizona.

This confirmation comes just four days after the CDC released new guidelines for the virus that include prevention measures such as the use of condoms and abstinence for those sexually active.

As of March 25th, in the United States there have been 273 confirmed cases of travel associated Zika infections, 19 of which are pregnant women. In the US territories, there have been 282 locally acquired Zika Infections, 4 travel associated case, and out of those 282, 34 are pregnant women.

If you or someone you know has traveled to a Zika affected area (list here), and are displaying Zika symptoms (here), please see your doctor, or contact your local public health agency.

 

Zika on the rise!

A little over a week ago, I posted a description of a now looking to become pandemic virus: Zika (you can read the previous description here). Zika virus has been around for decades, with a few cases here and there, but recently, a surge in the virus in South America has had Health Organizations scrambling to determine the threat against the global population.

Zika virus is now spreading to more countries and new advisories are going out:

  • The first case of Zika in the United States was confirmed in Texas, and transmitted through sexual intercourse.
  • First pregnant woman in Spain confirmed with Zika virus
  • CDC has stated that limiting sexual activities with a pregnant partner if living or travelling to Zika infected areas.
  • Florida’s Governor Issued a State of Emergency in the counties that 12 confirmed Zika cases are- None of which were infected in the United States.
  • Brazil has found Active Zika virus in urine and saliva.
  • El Salvador advises its citizen to avoid pregnancy for up to 2 years.
  • New York has 11 confirmed cases of Zika.
  • Pennsylvania has two confirmed cases
  • Delaware has 1 confirmed case
  • Ohio has 1 confirmed case
  • Indiana has 1 confirmed case
  • WHO states that as many as 3 to 4 million people are infected in Central and South America
  • CDC issued Travel alerts to 28 countries.
  • Three deaths of individuals with Zika virus in Venezuela (caused by complications not currently linked to infection).
  • 52 cases of travel acquired Zika virus confirmed in United States

The World Health Organization convened its first emergency meeting to discuss the Zika virus, its epidemiology, clinical signs and symptoms, spread, and link to neurological disorders and microcephaly. The committee then submitted guidelines to be approved:

  • The increased and enhanced surveillance of microcephaly and Guillain-Barre syndrome in areas with outbreaks of Zika or with potential to become an area
  • Research into the etiology of microcephaly and Guillain-Barre syndrome to determine causal links.

They also issued additional recommendations in precautionary measures:

Zika virus

  • Surveillance enhancement
  • Prioritization of  new diagnostics.
  • Risk communications should be enhanced to address
    • population concerns
    • enhance community engagement
    • improve reporting
    • ensure application of vector control and personal protective measures.
  • Control measures and PPE should be implemented.
  • Education of Pregnant women or those intending to become pregnant in how to reduce risk.
  • Resources should be provided to pregnant women exposed to virus

Longer-term measures

  • Appropriate research and development efforts into vaccines, therapeutics and diagnostics.
  • Increase in health services preparation for potential increase in neurological or congenital birth defects.

A recent article from Bogoch et al. has determined a potential transmission map for how the Zika virus might spread. Taking into account the number of people who travel in and out of Brazil, the researchers determine that the rest of Central and Northern South American countries will see a drastic increase, as well as the Caribbeans, Florida and will continue to spread up through the Eastern Seaboard of North America.

Zika.jpgBogoch et. Al.  2016. Anticipating the international spread of Zika virus from Brazil. The Lancet.

Conclusion:

The most important thing to remember about Zika virus is that it normally does not lead to death. The majority of individuals infected do not display symptoms and are not sick. the recent rash of Zika infection is unprecedented and researchers around the world are working faster diagnostics tests, treatment options and vaccines.

Holiday Gifts for my Fellow Science Nerds!

Choosing holiday gifts are difficult for the regular person- but if you are trying to figure out what to get for your buried in a lab- nose in a textbook friend- here are some gift ideas!

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Kitchenware
GeNiUs coffee mugs – $50
GeNiUs

Test Tub Tea Infuser – $11

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Beaker Mug – $12
Beaker mug

Caffiene Molecule Mug –  $23
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Periodic Table Coaster Set – $20
Coaster Set

Jewelry

Anatomical Heart – $16-180 depending on metal used
Anatomical Heart

DNA Base Pair Molecules – $35+
Base Pair

DNA Helix Pendent – $29
DNA Helix

Chemical Formulas – Dopamine, Serotonin, and Acetylcholine – $2+
Molecular Formula Jewelry

Solar System Necklace – $31
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For the Chemical Nerds:

Periodic Table Shower Curtain – $30
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And finally…For those who love the little wiggly microbes-

Microbe Plushies! – $10-25
bacteria

 

Have Happy Holidays my fellow Science Nerds!