Download Chlamydophila pneumoniae is a species of Chlamydophila bacteria

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Major Diseases Transmitted By Air - Lists the major diseases transmitted via air. Since air enters the
body through the respiratory tract and since such diseases frequently localize in the nose and throat, they are
called respiratory diseases as a group.
1.Bacterialo
2.Viral
3.Fungal
Diphtheria,Septic sore tnroat,Scarlet fever,Rheumatic fever.
Tuberculosis,pneumonia,Meningitis,Whooping cough.
Small
pox,
Chicken
pox,
Measles,German
Measles,Mumps,influenzea,Common cold,psittacosis.
Systemic mycoses.
Broadly they can be of three kinds:
1. Infection of the respiratory tract like common cold, influenza, sore throat and pneumonia.
2. Specific fevers like measles, whooping cough, diphtheria, scarlet fever, etc.
3. Specific respiratory infections, the most important of which is pulmonary tuberculosis.
In addition, some infections may be acquired by inhalation of dried, infective excreta or secretions, e.g.
psittacosis and Q fever.
Direct Droplet
It requires intimate contact and it may be difficult to be sure whether the infective material has been directly
inhaled from the dispersed droplets or whether it has reached the respiratory tract of the susceptible person
indirectly through the medium like hands, fomites etc. Direct droplet spread would seem to be the most
likely method for transfer of respiratory pathogens that have a poor viability outside the body, e.g.
cerebrospinal fever (associated with conditions of overcrowding in jails and ships).
Another example is whooping cough. The infecting microbes are in the active phase of growth and therefore
are more likely to be able to attack the tissues in which they are implanted.
Direct Airborne
Most of the droplets that are expelled from the mouth during talking, coughing and sneezing fall quickly to
the ground or onto the clothing of the person in question. A proportion of the expelled droplets are however
so small that by rapid evaporation they remain suspended in the air like particles of smoke and may be
carried to considerable distances by air current from the coughing or sneezing individuals by air currents.
These tiny droplets may contain infective material (virus infection) with the result that individuals at some
distances from the infectious person may become infected. Among human infections, measles and chicken
pox are spread in this way. It is inherent in this mode of spread that the infecting dose must often be very
small.
Indirect Airborne
Most of the larger droplets expelled during talking and coughing become dried particles of dust on exposed
surfaces or on clothing, bed cloths or handkerchieves. If they contain respiratory pathogens that resist
natural drying, this dust when raised in the air during activities such as dusting, sweeping, bed-making or
shaking of a handkerchief could be inhaled and may set up infection. Dust-borne spread has been proved for
certain viral and rickettsial infections such as psittacosis and Q fever. Dust particles can harbour various
pathogens.
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Staphylococci and streptococci can survive on dust and be transmitted by the airborne route. Spores
produced by certain fungi are also transmitted by the airborne route and can cause such diseases as
histoplasmosis; coccidioidomycosis and blastomycosis.
A number of potentially pathogenic microorganisms are part of the normal microbiota in the upper
respiratory tract. They do not cause illness because the predominant microorganisms of the normal
microbiota suppress their growth by competing with them for nutrients and producing inhibitory substances.
Airborne pathogens make their first contact with the body's mucous membranes as they enter the upper
respiratory tract. Many respiratory and systemic diseases initiate infections here.
Diseases of The Upper Respiratory System
The upper respiratory tract consists of external nares and upper part of the pharynx.
Bacterial Diseases
Streptococcal pharyngitis (strep throat)
It is an upper respiratory tract infection caused by group AB haemolytic streptococci - Streptococcus
pyogenes.
The pathogen is resistant to phagocytosis.
This organism can be detected in the throat of many people who are
asymptomatic carriers.
This is characterised by local inflammation and fever with tonsillitis.
Another complication is otitis media (infection of the middle ear).
Penicillin is the drug of choice.
Scarlet fever
When the Streptococcus pyogenes strain produces an erythrogenic (reddening) toxin the infection is called
scarlet fever.
It is a communicable disease spread mainly by inhalation of infective droplets from an infected person.
Diphtheria
Until 1935, it was the leading infectious killer of children.
Disease begins with a sore throat and fever followed by general malaise and swelling of neck.
Causative organism is Corynebacterium diphtheriae which is a gram positive non-spore-forming rod.
The bacterium is well-suited to airborne transmissions and is very resistant to drying.
Otitis media
One of the uncomfortable complications of common cold.
Caused by Streptococcus pneumoniae, Haemophilus influenzae, Moraxella
catarrhalis, S. pyogenes and Staphylococcus aureus.
Viral Diseases
Common cold
Caused by rhinoviruses (50%), coronaviruses (15-20%). 10% of all colds caused by several other viruses.
There are at least 113 serotypes of rhinoviruses.
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Symptoms are sneezing, excessive nasal secretions and congestion.
Rhinoviruses thrive at a temperature slightly below that of normal body temperature (found in the upper
respiratory tract).
A single rhinovirus particle deposited on the nasal mucosa is sufficient to cause a cold.
Diseases Of The Lower Respiratory Tract
Lower respiratory tract consists of larynx, trachea, bronchial tubes and alveoli (air sacs that make up the
lung tissue).
Bacterial Diseases
Pertussis (whooping cough, per-thoroughly and tussis-cough)
Causative organism is Bordetella pertussis which is a small obligately aerobic capsulated gram negative
coccobacillus.
It is primarily a childhood disease and can be quite severe. Initial stage resembles a common cold.
Mortality rates among children is quite high.
Disease is transmitted by inhaling pathogens expelled by the coughing of the infected person.
Transmission rate is 90% among non-immune contacts.
Tuberculosis
Causative organism, Mycobacterium tuberculosis is a slender acid fast rod and obligate aerobe which is a
slow grower.
On the surface of the liquid media, their growth appears mold-like hence the name Mycobacterium.
TB is most commonly acquired by inhaling the tubercle bacillus.
Bacterial pneumonias Pneumonia is a pulmonary infection caused by bacteria.
Pneumococcal pneumonia
Caused by S. pneumoniae which is a gram positive capsulated ovoid bacterium in pairs.
Involves bronchi and alveoli with high fever, breathing difficulty and chest pain.
Sputum is rust colour because of blood coughed up from lungs.
H. Influenzae pneumonia
Caused by gram negative coccobacilli.
Has similar symptoms as common cold.
Mycoplasmal pneumonia
Causative organism is Mycoplasma pneumoniae.
They are fastidious organisms which lack cell wall and show very small colonies on solid media.
The disease is endemic and is the common cause of pneumonia in children.
Transmitted by airborne droplets.
Infects the upper respiratory tract initially with low fever, cough and headache followed by the lower
respiratory tract infection.
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Legionellosis
Legionnaires disease is caused by an aerobic gram negative rod Legionella pneumophila. (pneumo-Iung,
phila-Ioving).
Characterised by high fever of 105°F, cough and general symptoms of pneumonia.
Microbes can grow in the water of air conditioners and cooling towers, the cause of epidemic in hotels and
hospitals through airborne transmission.
Psittacosis (ornithosis)
Term is derived from the diseases associated with psittacine birds (parakeets, parrots).
Causative agent is Chlamydia psittaci which is a gram negative obligate intracellular bacterium.
They produce tiny elementary bodies as part of their life cycle. These elementary bodies are resistant to
environmental conditions, and therefore are transmitted through air.
Psittacosis is a form of pneumonia that causes fevers, headache and chills with delirium (disorientation).
Psittacosis is a form of pneumonia that causes fevers, headache and chills with delirium (disorientation).
One of the most common modes of transmission is inhalation of dried particles from droppings of birds.
Chlamydophila pneumoniae is a species of Chlamydophila bacteria that infects humans and is a major
cause of pneumonia.
Symptoms of infection with C. pneumoniae are indistinguishable from other causes of pneumonia. These
include cough, fever, and difficulties breathing. A slightly red hard palate, and a whitening of the back of
the tongue are very common. Patients infected with C. pneumoniae often have nasal congestion, chest
pressures and depression. C. pneumoniae more often causes pharyngitis, laryngitis, and sinusitis than other
causes of pneumonia; however, because many other causes of pneumonia result in these symptoms,
differentiation is not possible. Likewise, a physical examination by a health provider does not typically
provide information which allows for a definite diagnosis.
Q fever (query fever)
Caused by a rickettsial member Coxiella burnettii.
Symptoms are undulating fever (1-2 weeks) with chills, chest pain severe headache.
This organism is resistant enough to survive airborne transmission.
This pathogen is a parasite among arthropods (ticks) which transmit the organism to cattle and dairy herds
following which the microbes are shed in milk, faeces and urine of infected cattle.
Once the disease is established in a herd, it is maintained by aerosol transmission.
The disease can be spread by inhaling aerosols of microbes generated in dairy barns, especially from
placental material at calving time.
Inhaling a single pathogen is enough to cause infection.
Viral Diseases
Smallpox
Smallpox was an infectious disease unique to humans, caused by either of two virus variants, Variola major
and Variola minor. Smallpox is caused by infection with variola virus, which belongs to the genus
Orthopoxvirus, the family Poxviridae and subfamily chordopoxvirinae. Variola is a large brick-shaped virus
measuring approximately 302 to 350 nanometers by 244 to 270 nm, with a single linear double stranded
DNA Smallpox localizes in small blood vessels of the skin and in the mouth and throat. In the skin, this
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results in a characteristic maculopapular rash, and later, raised fluid-filled blisters. V. major produces a
more serious disease and has an overall mortality rate of 30–35%. V. minor causes a milder form of disease
(also known as alastrim, cottonpox, milkpox, whitepox, and Cuban itch). Long-term complications of V.
major infection include characteristic scars, commonly on the face, which occur in 65–85% of survivors.
Blindness resulting from corneal ulceration and scarring, and limb deformities due to arthritis and
osteomyelitis are less common complications, seen in about 2–5% of cases. Transmission
Transmission occurs through inhalation of airborne variola virus, usually droplets expressed from the oral,
nasal, or pharyngeal mucosa of an infected person. It is transmitted from one person to another primarily
through prolonged face-to-face contact with an infected person, usually within a distance of 6 feet (1.8 m),
but can also be spread through direct contact with infected bodily fluids or contaminated objects (fomites)
such as bedding or clothing. Rarely, smallpox has been spread by virus carried in the air in enclosed settings
such as buildings, buses, and trains
Human parainfluenza viruses (HPIVs) are a group of four distinct serotypes of single-stranded RNA
viruses belonging to the paramyxovirus family. They are the second most common cause of lower
respiratory tract infection in younger children.
Viral pneumonia This occurs as a complication of influenza, measles or even chicken pox.
Viral pneumonia is a pneumonia caused by a virus. Viruses are one of the two major causes of pneumonia,
the other being bacteria; less common causes are fungi and parasites. Viruses are the most common cause of
pneumonia in children, while in adults bacteria are a more common cause. Common causes of viral
pneumonia are:
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
Influenza virus A and B
Respiratory syncytial virus (RSV)
Human parainfluenza viruses (in children)
Rarer viruses that commonly result in pneumonia include:
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Adenoviruses (in military recruits)
Metapneumovirus[citation needed]
Severe acute respiratory syndrome virus (SARS coronavirus)
Viruses that primarily cause other diseases, but sometimes cause pneumonia include:



Herpes simplex virus (HSV), mainly in newborns
Varicella-zoster virus (VZV)
Cytomegalovirus (CMV), mainly in people with immune system problems
Respiratory syncytial virus (RSV)
Most common cause of viral respiratory disease in infants.
Symptoms are coughing and wheezing lasting for more than a week.
All children become infected by the age of two.
Human respiratory syncytial virus (RSV) is a virus that causes respiratory tract infections. It is the major
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cause of lower respiratory tract infection and hospital visits during infancy and childhood. There is no
vaccine, and the only treatment is oxygen.
RSV is a negative-sense, single-stranded RNA virus of the family Paramyxoviridae, which includes
common respiratory viruses such as those causing measles and mumps. RSV is a member of the
paramyxovirus subfamily Pneumovirinae. Its name comes from the fact that F proteins on the surface of the
virus cause the cell membranes on nearby cells to merge, forming syncytia. For most people, RSV produces
only mild symptoms, often indistinguishable from common colds and minor illnesses. The Centers for
Disease Control consider RSV to be the "most common cause of bronchiolitis (inflammation of the small
airways in the lung) and pneumonia in children under 1 year of age. Recurrent wheezing and asthma are
more common among individuals who suffered severe RSV infection.
Influenza (viral flu)
Characterised by chills, fever, headache and muscular ache.
Caused by influenza virus.
The Orthomyxoviridae (orthos, Greek for "straight"; myxa, Greek for "mucus") are a family of RNA
viruses that includes five genera: Influenzavirus A, Influenzavirus B, Influenzavirus C, Isavirus and
Thogotovirus. A sixth has recently been described. The first three genera contain viruses that cause
influenza in vertebrates, including birds (see also avian influenza), humans, and other mammals. Isaviruses
infect salmon; thogotoviruses infect vertebrates and invertebrates, such as mosquitoes and sea lice. The
three genera of Influenzavirus, which are identified by antigenic differences in their nucleoprotein and
matrix protein infect vertebrates as follows:
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Influenzavirus A cause of all flu pandemics and infect humans, other mammals and birds
Influenzavirus B infect humans and seals
Influenzavirus C infect humans and pigs
Chickenpox
Chickenpox is a common illness among kids, particularly those under age 12. An itchy rash of spots that
look like blisters can appear all over the body and may be accompanied by flu-like symptoms. Symptoms
usually go away without treatment, but because the infection is very contagious, an infected child should
stay home and rest until the symptoms are gone.Chickenpox is caused by the varicella-zoster virus (VZV-DNA Virus-Herpesvirus ). Symptoms of Chickenpox
Chickenpox causes a red, itchy rash on the skin that usually appears first on the abdomen or back and face,
and then spreads to almost everywhere else on the body, including the scalp, mouth, nose, ears, and genitals.
The rash begins as multiple small, red bumps that look like pimples or insect bites. They develop into thinwalled blisters filled with clear fluid, which becomes cloudy. The blister wall breaks, leaving open sores,
which finally crust over to become dry, brown scabs.
Measles
Measles, also called rubeola, is a highly contagious - but rare - respiratory infection that's caused by a
Paramyxovirus (RNA)virus. It causes a total-body skin rash and flu-like symptoms, including a fever,
cough, and runny nose.
Signs and Symptoms
While measles is probably best known for the full-body rash that it causes, the first symptoms of the
infection are usually a hacking cough, runny nose, high fever, and watery red eyes. Another marker of
measles are Koplik's spots, small red spots with blue-white centers that appear inside the mouth.
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The measles rash typically has a red or reddish brown blotchy appearance, and first usually shows up on
the forehead, then spreads downward over the face, neck, and body, then down to the feet.
Measles is highly contagious. When someone with measles sneezes or coughs, he or she can spread virus
droplets through the air and infect others.
Rubella — commonly known as German measles
Rubella — commonly known as German measles or 3-day measles — is an infection that primarily affects
the skin and lymph nodes. It is caused by the rubella virus (not the same virus that causes measles), which is
Togavirus -RNA
virus usually transmitted by droplets from the nose or throat that others breathe in. It can also pass through a
pregnant woman's bloodstream to infect her unborn child.
Contagiousness
The rubella virus passes from person to person through tiny drops of fluid from the nose and throat. People
who have rubella are most contagious from 1 week before to 1 week after the rash appears. Someone who is
infected but has no symptoms can still spread the virus.
Fungal Diseases
Fungi often produce spores that are airborne and are causative agents of
various diseases.
Histoplasmosis
It resembles TB superficially.
Symptoms are sub-clinical.
Caused by Histoplasma capsulatum which is a dimorphic fungus (yeast-like inside the tissue and
filamentous in artificial media).
Disease is acquired from airborne conidia produced under conditions of appropriate moisture and pH.
Histoplasmosis (also known as "Cave disease, Darling's disease, Ohio valley disease, and
"Reticuloendotheliosis) is a disease caused by the fungus Histoplasma capsulatum. Symptoms of this
infection vary greatly, but the disease primarily affects the lungs. Occasionally, other organs are affected;
this is called disseminated histoplasmosis, and it can be fatal if untreated. Histoplasmosis is common among
AIDS patients because of their lowered immune system.
Symptoms
If symptoms of histoplasmosis infection occur, they will start within 3 to 17 days after exposure; the average
is 12–14 days. Most affected individuals have clinically silent manifestations and show no apparent ill
effects. The acute phase of histoplasmosis is characterized by non-specific respiratory symptoms, often
cough or flu-like. Chest X-ray findings are normal in 40–70% of cases.[2] Chronic histoplasmosis cases can
resemble tuberculosis; disseminated histoplasmosis affects multiple organ systems and is fatal unless treated
Coccidioidomycosis
Causative organism is Coccidioides immitis which is a dimorphic fungus. Within tissues, the organism
forms a thick-walled body filled with spores called spherules. In soil, it forms filaments which reproduce by
formation of arthrospores which are carried by wind to transmit the infection.
Laboratory workers must take great care because of the possibility of infectious aerosols.
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Pneumocystis pneumonia (PCP) or pneumocystosis is a form of pneumonia, caused by the yeast-like
fungus Pneumocystis jirovecii. This pathogen is specific to humans. It has not been shown to infect other
animals, while other species of Pneumocystis that parasitize other animals (all of which are mammals) have
not been shown to infect humans.
Pneumocystis is commonly found in the lungs of healthy people, but being a source of opportunistic
infection it can cause a lung infection in people with a weakened immune system. Pneumocystis pneumonia
is especially seen in people with cancer, HIV/AIDS and the use of medications that affect the immune
system.
Blastomycosis
Causative organism is Blastomyces dermatitidis which is a dimorphic
fungus.
Infection begins in the lungs and spreads rapidly.
Aspergillosis
Causative organism is Aspergillus fumigatus.
Common among gardeners and farmers due to the spores which are
widespread in decaying vegetation.
Rhizopus and Mucor species also cause pulmonary infections.
Allergic rhinitis, pollenosis or hay fever is an allergic inflammation of the nasal airways. It occurs when
an allergen such as pollen or dust is inhaled by an individual with a sensitized immune system, and triggers
antibody production. The specific antibody is immunoglobulin E (IgE) which binds to mast cells and
basophils containing histamine. IgE bound to mast cells are stimulated by pollen and dust, causing the
release of inflammatory mediators such as histamine (and other chemicals).This causes itching, swelling,
and mucus production. Symptoms vary in severity between individuals. Very sensitive individuals can
experience hives or other rashes. Particulate matter in polluted air and chemicals such as chlorine and
detergents, which can normally be tolerated, can greatly aggravate the condition. The first description of hay
fever was by John Bostock in 1819
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