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Currently, there is no universally accepted vaccine for Hansen’s disease. India and Brazil use a tuberculosis vaccine against Hansen’s disease because both diseases are caused by species of Mycobacterium . The effectiveness of this method is questionable, however, since it appears that the vaccine works in some populations but not in others.

a) Black tissue on end of nose. B) Small purple cells next to larger blue ones.
(a) The nose of a patient with Hansen’s disease. Note the lepromatous/multibacillary lesions around the nostril. (b) Hansen’s disease is caused by Mycobacterium leprae , a gram-positive bacillus. (credit a, b: modifications of work by the Centers for Disease Control and Prevention)
  • What prevents the progression from tuberculoid to lepromatus leprosy?
  • Why does Hansen’s disease typically affect the nerves of the extremities?

Leper colonies

Disfiguring, deadly diseases like leprosy have historically been stigmatized in many cultures. Before leprosy was understood, victims were often isolated in leper colonies, a practice mentioned frequently in ancient texts, including the Bible. But leper colonies are not just an artifact of the ancient world. In Hawaii, a leper colony established in the late nineteenth century persisted until the mid-twentieth century, its residents forced to live in deplorable conditions. National Park Service, “A Brief History of Kalaupapa,” Accessed February 2, 2016. http://www.nps.gov/kala/learn/historyculture/a-brief-history-of-kalaupapa.htm. Although leprosy is a communicable disease, it is not considered contagious (easily communicable), and it certainly does not pose enough of a threat to justify the permanent isolation of its victims. Today, we reserve the practices of isolation and quarantine to patients with more dangerous diseases, such as Ebola or multiple-drug-resistant bacteria like Mycobacterium tuberculosis and Staphylococcus aureus . The ethical argument for this practice is that isolating infected patients is necessary to prevent the transmission and spread of highly contagious diseases—even when it goes against the wishes of the patient.

Of course, it is much easier to justify the practice of temporary, clinical quarantining than permanent social segregation, as occurred in leper colonies. In the 1980s, there were calls by some groups to establish camps for people infected with AIDS. Although this idea was never actually implemented, it begs the question—where do we draw the line? Are permanent isolation camps or colonies ever medically or socially justifiable? Suppose there were an outbreak of a fatal, contagious disease for which there is no treatment. Would it be justifiable to impose social isolation on those afflicted with the disease? How would we balance the rights of the infected with the risk they pose to others? To what extent should society expect individuals to put their own health at risk for the sake of treating others humanely?

Bacterial infections of the nervous system

Despite the formidable defenses protecting the nervous system, a number of bacterial pathogens are known to cause serious infections of the CNS or PNS. Unfortunately, these infections are often serious and life threatening. [link] summarizes some important infections of the nervous system.

Table titled: Bacterial Infections of the Nervous System. Columns: Disease; Pathogen; Signs and Symptoms; Transmission; Antimicrobial Drugs; Vaccine. Disease: Botulism; Clostridium botulinum; Blurred vision, drooping eyelids, difficulty swallowing and breathing, nausea, vomiting,often fatal; Ingestion of preformed toxin in food, ingestion of endospores in food by infants or immunocompromised adults, bacterium introduced via wound or injection; Antitoxin; penicillin (for wound botulism)l; None. Disease: Hansen’s disease (leprosy); Mycobacterium leprae; Hypopigmented skin, skin lesions, and nodules, loss of peripheral nerve function, loss of fingers, toes, and extremities; Inhalation, possible transmissible from armadillos to humans; Dapsone, rifampin, clofazimin; None. Haemophilus influenzae type b meningitis; Haemophilus influenza; Nausea, vomiting, photophobia, stiff neck, confusion; Direct contact, inhalation of aerosols; Doxycycline, fluoroquinolones, second- and third-generation cephalosporins, and . carbapenems; Hib vaccine. Disease: Listeriosis; Listeria monocytogenes; Initial flu-like symptoms, sepsis and potentially fatal meningitis in susceptible individuals, miscarriage in pregnant women; Bacterium ingested with contaminated food or water; Ampicillin, gentamicin; None . Disease: Meningococcal meningitis; Neisseria meningitidis; Nausea, vomiting, photophobia, stiff neck, confusion; often fatal; Direct contact; Cephalosporins or penicillins; Meningococcal conjugate. Disease: Neonatal meningitis; Streptococcus agalactiae; Temperature instability, apnea, bradycardia, hypotension, feeding difficulty, irritability, limpness, seizures, bulging fontanel, stiff neck, opisthotonos, hemiparesis, often fatal; Direct contact in birth canal; Ampicillin plus gentamicin, cefotaxime, or both; None. Pneumococcal meningitis; Streptococcus pneumoniae; Nausea, vomiting, photophobia, stiff neck, confusion, often fatal; Direct contact, aerosols; Cephalosporins, penicillin; Pneumococcal vaccines. Disease: Tetanus; Clostridium tetani; Progressive spasmatic paralysis starting with the jaw, often fatal; Bacterium introduced in puncture wound; Penicillin, antitoxin; DTaP, Tdap.

Key concepts and summary

  • Bacterial meningitis can be caused by several species of encapsulated bacteria, including Haemophilus influenzae , Neisseria meningitidis , Streptococcus pneumoniae , and Streptococcus agalactiae (group B streptococci). H. influenzae affects primarily young children and neonates, N. meningitidis is the only communicable pathogen and mostly affects children and young adults, S. pneumoniae affects mostly young children, and S. agalactiae affects newborns during or shortly after birth.
  • Symptoms of bacterial meningitis include fever, neck stiffness, headache, confusion, convulsions, coma, and death.
  • Diagnosis of bacterial meningitis is made through observations and culture of organisms in CSF. Bacterial meningitis is treated with antibiotics. H. influenzae and N. meningitidis have vaccines available.
  • Clostridium species cause neurological diseases, including botulism and tetanus , by producing potent neurotoxins that interfere with neurotransmitter release. The PNS is typically affected. Treatment of Clostridium infection is effective only through early diagnosis with administration of antibiotics to control the infection and antitoxins to neutralize the endotoxin before they enter cells.
  • Listeria monocytogenes is a foodborne pathogen that can infect the CNS, causing meningitis. The infection can be spread through the placenta to a fetus. Diagnosis is through culture of blood or CSF. Treatment is with antibiotics and there is no vaccine.
  • Hansen’s disease ( leprosy ) is caused by the intracellular parasite Mycobacterium leprae . Infections cause demylenation of neurons, resulting in decreased sensation in peripheral appendages and body sites. Treatment is with multi-drug antibiotic therapy, and there is no universally recognized vaccine.

Fill in the blank

The form of meningitis that can cause epidemics is caused by the pathogen ________.

Neisseria meningitidis

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The symptoms of tetanus are caused by the neurotoxin ________.

tetanospasmin

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________ is another name for leprosy.

Hansen’s disease

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Botulism prevents the release of the neurotransmitter ________.

acetylcholine

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________ is a neurological disease that can be prevented with the DTaP vaccine.

Tetanus

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Tetanus patients exhibit ________ when muscle spasms causes them to arch their backs.

opisthotonos

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Short answer

A physician suspects the lesion and pustule pictured here are indicative of tuberculoid leprosy. If the diagnosis is correct, what microorganism would be found in a skin biopsy?

Discolored tissue.
(credit: Centers for Disease Control and Prevention)
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Questions & Answers

what are the two acids the skin produce
Caro Reply
alpha hydroxy and beta hydroxy there are water soluble compounds and often use as exfoliant
Enow
what must a positive strand of an RNA virus do first
Kelsi-Ann Reply
A positive-sense single-stranded RNA virus (or (+)ssRNA virus) is a virus that uses positive sense single stranded RNA as its genetic material. Single stranded RNA viruses are classified as positive or negative depending on the sense or polarity of the RNA.
Dejene
 The positive-sense viral RNA genome can serve as messenger RNA and can be translated into protein in the host cell. Positive-sense ssRNA viruses belong to Group IV in the Baltimore classification. Positive-sense RNA viruses account for a large fraction of known viruses, including many pathogens
Dejene
such as the hepaci virus C, West nail virus, dengue virus, SARS and MERS coronaviruses, and SARS-CoV-2 as well as less clinically serious pathogens such as the rhinoviruses that cause the common cold.
Dejene
Why strong acid and alkline are not harmful to mycobacterium bacili?
Brian
What are the types of bacteria
John Reply
Do you mean the shapes or the the two different types of bacteria? Bacteria are often described in terms of their general shape. Common shapes include spherical (coccus), rod-shaped (bacillus), or curved (spirillum, spirochete, or vibrio) The two different types are gram negative or gram positive.
Melanie
what other characteristics of prokaryotes a bacteria don't have?
Brian
Prokaryotes are single-celled organisms belonging to the domains Bacteria and Archaea. Prokaryotic cells are much smaller than eukaryotic cells, have no nucelus, and lack organelles. All prokaryotic cells are encased by a cell wall. Many also have a capsule or slime layer made of polysaccharide.
Dejene
gram positive bacteria and gram negative bacteria
mubeen
Most bacteria can be broadly classified as Gram positive or Gram negative. Gram positive bacteria have cell walls composed of thick layers of peptidoglycan.cells stain purple when subjected to a Gram stain procedure. Gram negative bacteria have cell walls with a thin layer of peptidoglycan.
Dejene
all of you are amazing microbiologists
demisew
thanks demisew....
Dejene
guys what are the two acids the skin produce
Caro
what are the bacteria's involved in the decaying of food
Enow Reply
Some pathogenic bacteria, such as Clostridium perfringens and Bacillus cereus, are capable of causing spoilage.
Dejene
Corona has a gray and black cell structure ....if yes explain..if no explain
Joshua Reply
multiple questions and answers in microbiology and bio chemistry
Lakshmi Reply
is the study of a bacteria and other organisms
isir
yes..this book is about bacteria & others organisms
Hasan
biochemistry is the branch of science that dealing of chemical compounds reactions and other processes
isir
have you any question?
Hasan
yess, Why scientists not search coronavirus vaccines in short time.
demisew
they are on
Monyditchol
what are the symptoms for tuberculosis
Chiamaka
Most people infected with the bacteria that cause tuberculosis don't have symptoms. When symptoms do occur, they usually include a cough (sometimes blood-tinged), weight loss, night sweats and fever.
Dejene
symptoms tuberculosis. Fever Chills Night sweats Cough Loss of appetite Weight loss Blood in the sputum (phlegm) Loss of energy
lourdes
can corona virus transmitted from mother to her child through placenta ?
Abdul
probably
Mad
no
Oke
no,but it can through trait
Falere
mutation occur in the genome of corona virus. thats why the corona vaccines forming just difficult
Muzamil
intersted
Do
no
Esther
No
John
Yes
Suhaib
yes
Benjamin
yes coz it's spread through the soft body parts more so the openings in our bodies
Rebecca
Yes
Ayan
what is relation between fear (from covid 19 ) and immune sys ?
Abdul
because it damages the immune system by reduction the action of WBC
mike
reducing pls
mike
how is it possible for a woman to be pregnant and still See's her period
Prince Reply
we term it as discharge
Monyditchol
what is immunity
evans Reply
What is a varuis
evans
A submicroscopic infectious organism, now understood to be a non-cellular structure consisting of a core of DNA or RNA surrounded by a protein coat. It requires a living cell to replicate, and often causes disease
Ebo
A virus is a biological agent that reproduces inside the cells of living hosts. When infected by a virus, a host cell is forced to produce thousands of identical copies of the original virus at an extraordinary rate
Dejene
A virus is a microorganism which invade our bodies causing diseases due to eliciting immune responses by the body against it, can replicate using our genome inducing production of proteins helping them to establish new life inside our bodies.
What are the important of capsules
Marriam Reply
what are the roles of male sex hormones
Marriam
Testosterone is the principal sex hormone inmales and is produced in the testes (testicles). Dihydrotestosterone is a hormonein which the double bond of testosterone has been reduced by enzyrne reactions in the body. ... The testes perform two functions: They produce sperm, and they producetestoster
Dejene
Capsules in bacteria protect them from phagocytosis of eukaryotic organisms. This is what makes them virulent and harmful without antibodies.
Lewis
any one told me definition of amoebic dysentery & amoebic liver dysentery?
Mira
Amoebiasis, also known amoebic dysentery, is an infection caused by any of the amobae of the Entamoeba group. Symptoms are most common during infection by Entamoeba histolytica. Amoebiasis can be present with no, mild, or severe symptoms. Symptoms may include abdominal pain, diarrhea....
Dejene
tnx
Mira
u welcome mira
Dejene
people explain for me this words in public health.tb prevention 1:promotive 2:preventive 3:curative 4:rehabilitative
Obrian
Capsules function similarly to endospores they provide an extra layer of protection especially in acidic or basic environments. It is also a thicker membrane which can change the osmosis process and can provides resistance to antibotics depending if it is gram negative or positive.
Melanie
...As some antibotics focus on breaking down the cell wall and is not able to.
Melanie
what are the clinical classification of amoxicillin?
Rebecca
how does a autoimmune diso ders develop
Oliver Reply
simply autoimmune disease is not completely understood. There are many variations from genetically inherited to acquired by viruses like HIV. Genetically they may not be prominent until an unknown point in one's life. I am far from an expert, I am just reciting what I have learned. Take rheumatoid
Lewis
what is anatomy
Mohamed Reply
Anatomy is the study of parts of the human body
Matilda
the branch of science concerned with the bodily structure of humans, animals, and other living organisms, especially as revealed by dissection and the separation of parts.
Dejene
Describe the halden effect
Suleiman
The Haldane effect is a property of haemoglobin first described by John ScottHaldane. Oxygenation of blood in the lungs displaces carbon dioxide from hemoglobin which increases the removal of carbon dioxide. This property is the Haldane effect.
Dejene
Difference between chief cells and parietal cells in the stomach
Suleiman
 Parietal cells are the epithelialcells that secrete HCl and intrinsic factor. They are located in the gastric glands found in lining of fundus and stomach. The gastric chief cells , are cells in the stomach that release pepsinogen and chymosin.
Dejene
is the study of structure and organs located in human life
isir
listen to Matilda
Lewis
essay on microbiology and how it contribute to the pharmacy assistant programme
Tagedevi Reply
I want to know how it contribute to the pharmacy assistant programme
chidiebube
Contribute how? If you want to contribute to pharmaceutical stuff you should look for websites with blogs that relate to your interests.
Lewis
hello i want to know how it contribute to microbiology programs
Dejene
Microbiology is the study of bacteria and and organisms such as viruses, fungi, and mold. How does this apply to medicine? It applies to medicine or pharmacology because when you get sick you are infected by a pathogen and understanding how these organisms interact with each other helps you to....
Melanie
develop medicine. A lot of bacteria infections can be cured with various medicines but not all medicines work equally. It depends if your sickness is based on gram positve or negative bacteria, if its s mold or fungus or a virius. Each medicine targets a certain one.
Melanie
If you need any ideas I recommend looking up Louis Pastar who used microbiology to invent a lot of medicines and contributed greatly to microbiology and pharmaceutical.
Melanie
what is a bacterial
Eric Reply
Bacteria is a microscopic organism belonging to the kingdom prokaryotic
John
what is prokaryotic
Oliver
if you are here, read this free book, it is mostly correct, there are a few pictures that should be corrected
Lewis
thanks
Eric
A prokaryotes does not have lipid- bilayer bound organelles, they can reproduce by binary fission, they have a DNA region, most have a cell well, contains a plasmid, 70s ribosomes, high mutation rate due lack of certain DNA replication enzymes.
Eric
HIV And Coronavírus, what is the difference ? Both are Retrovirus, please , I want to know. Thank you.
Cl Reply
does it mean Corona is incurable just like the HIV for the it to be retroviral too?
Joy
The reason researchers are looking to these medicines is that the new coronavirus—like HIV, Ebola, and hepatitis C—are all RNA viruses.but covid-19 is to detect human and animal virus. hiv is only human virus do not detecte animals
Dejene
***niaid.nih.gov/diseases-conditions/coronaviruses start here, since this is what is new, then recap yourself on autoimmune diseases that are not recoverable
Lewis
what happen when virus escape the host
Hailemichael
A virus must attach to a living cell, be taken inside, manufacture its proteins and copy its genome, and find a way to escape the cell so that the virus can infect other cells. Viruses can infect only certain species of hosts and only certain cells within that host.
Dejene
what is the difference between capsule and glycocylx in relation to prokaryotes
Felix Reply
However glycocalyx exists in bacteria as either a capsule or a slime layer. Thedifference between a capsule and a slime layer is that in a capsule polysaccharides are firmly attached to the cell wall, while in aslime layer, the glycoproteins are loosely attached to the cell wall.
Dejene
Glycocalyx is composed of glycosaminoglycans, proteoglycans and other glycoproteins bearing acidic oligosaccharides and terminal sialic acids. Capsule is Composed of polysaccharide (i.e. poly: many, saccharide: sugar). Exception: The capsule of Bacillus anthracis is composed of polymerized D-glutami
assarra
Capsule is located immediately exterior to the murein (peptidoglycan) layer  of gram-positive bacteria and the outer membrane (Lipopolysaccharide layer) of gram-negative bacteria The glycocalyx, which is located on the apical surface of endothelial cells, is composed of a negatively charged network
assarra
Meu I watch at microscopic HIV
Cl
assarra is paying attention. look into taking a course is you want to truly understand what is known now
Lewis

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Source:  OpenStax, Microbiology. OpenStax CNX. Nov 01, 2016 Download for free at http://cnx.org/content/col12087/1.4
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