Major Types Of ARVI

1) Influenza starts suddenly with severe intoxication, high temperature, photophobia, severe headache, body pain. By the end of first day appears dry cough. In most favorable course of the disease patient's common condition and temperature get normalized during five days.

2) Infection caused by parainfluenza virus starts gradually, with no intoxication, temperature never goes beyond 38C. Parainfluenza viruses mainly affect throat. The disease shows with symptoms of acute laryngitis (hoarseness of voice, dry cough).

3) Rhinovirus infection is characterized with nose hydrorrhea on the back of slightly frank symptoms of intoxication. Also patients suffer from tearing, frequent sneezing, no signs of affecting of trachea and bronchi. Temperature of the body is usually normal, in some cases it rises to 37-37,4°С.

4) Adenovirus infection is caused by viruses that affect not just epithelium of respiratory tract  but also lymphoid tissue. That is why besides symptoms of musous affection (nose hydrorrhea, unsymmetrical conjunctivitis, moderate cough on third day, fever on 8 – 12 day) are noticed increase of lymph glands, increased liver and spleen, abdomen pains. Despite high temperature, intoxication is not noticed.

5) Respiratory syncytial infection is characterized with affection of lower respiratory tract and has the same symptoms as bronchitis. Catarrhal syndrome is not significantly frank.

6) Coronaviral infection often affects upper respiratory tract. Clinical picture is similar to rhinovirus infection. Most frequently it affects children.

How to diagnose ARVI?
In order to make diagnosis it is necessary to make analysis of epidemical situation, symptoms, nature of cough, spit and nose mucus. To detect the agent it is necessary to make analysis that helps to detect viruses antigens due to immunofluorescence test.

ARVI (acute respiratory viral infection)

ARVI is an acute virus infection of respiratory tract that is characterized with high temperature (sometimes no temperature at all), intoxication symptoms, inflammation development. Inflammation may occur at any part of respiratory tract or at the whole respiratory tract (nose, paranasal sinuses, throat, trachea, bronchi). Also it may occur on conjunctiva.

Dramatic rise of the disease occurs in winter and in early spring. ARVI also occurs in autumn and some cases are registered all year round. Immunity after the diseases in past is strongly specific. It means that immunity is resistant to specific virus that causes ARVI. That is why one and the same adult may get diseased with ARVI up to 2 – 3 times a year and a child 6 – 8 times a year.

Agents of five virus groups cause ARVI. There are 300 viruses able to cause respiratory tract damage It is clear that each of them has its peculiarities. In summer and autumn the agents most frequently are agents of picornavirus group (rhinoviruses), in latest autumn and winter ARVI is caused by pneumotropic viruses (influenza)

Source of infection is diseased person with frank ARVI symptoms. Seldom source of infection are healthy virus carriers. Infection is transmitted via airborne. However, virus may be transmitted via contact with patient (handshake, kisses, objects). The immunity after carried virus infection usually remains resistant for a short period of time.

ARVI Symptoms

Any acute respiratory viral infection is manifested with next symptoms:
* acute onset of the disease
* body temperature increase
* symptoms of intoxication that are developed in first three days (headache, loss of appetite, weakness)
* appearing of catarrhal syndrome: stuffiness in nose, nasal discharge, sore throat, pharyngitis, tonsillitis, voice hoarseness, cough, eye conjunctiva.

Herpes Zoster

Herpes zoster is a disease resulting from the activation of the virus that stayed in the human body after chicken pox carried earlier. The disease is characterized with fever, general intoxication, pains and vesiculation along sensorial nerves,

Causes

With herpes zoster are diseased people in nervous system of which remains chicken pox virus for life. The disease usually affects older people.

How virus is activated?

Lowered with age immunity or severe diseases may activate chicken pox virus and causes nerves inflammation where the virus lives. Via sensorial nerves virus spreads into skin and mucus membranes where inflammation develops.

Symptoms

The disease starts acutely with increase of body temperature and full-blown burning pains, inch in spots of future rash. Pains appear on spots of affected nerves (often intercostal) and has one-way belting character. Sometimes pains become intolerable, they do increase when touching the skin, movements, cooling. In 3 – 4 days skin on pain spots becomes red and there appear groups with rare bladders filled with transparent liquid which soon becomes turbid. With appearing of cutaneous eruption, pains usually become less intense, but every second patient suffers from these pains for a month. In 3 – 5 days bladders dry up and turn into crusts.

The total duration of the disease is 7 – 10 days. However, in people with significantly lowered immunuty the disease courses more severe and long.

When in process get involved cranial nerves, pains and rash may appear on facial skin, mucus membranes of eyes and nose, earflap or acoustic meatus.

Complications

Almost in 10% of patients with herpes zoster pains in affected area last for more than one month. In some patients pains return back after one year of recovery.

Recognition

The appearing of one-way vesiculation with pains along intercostal space helps to make the diagnosis.

Treatment

It is necessary to start herpes zoster treatment after first disease manifestations (first days of rash appearing). All patients (especially people younger 20 years) must examine in order to find the reasons for immunity lowering.

Preventive measures

Healthy lifestyle.

Ways Of Hepatitis Diagnostication

Q: When it is necessary to make examination after unprotected sex?

A: It is necessary to undergo polymerase chain reaction (PCR) in 10 days after having unprotected sex. Antibodies test will give information only in 1-3 months.

Q: Is it possible to get recovered more rapidly if PCR detected virus in blood immediately after infection?

A: Test will show if you are infected or not, and also will help your partner to vaccinate. However, for the treatment is not so important when diagnosis was made – in several days or weeks after infection. It was proved that treatment delay even for a few months never aggravates the result but it is virulent to delay treatment more than one year.

Frequently, doctors choose waiting game when they meet hepatitis B. Acute hepatitis B in adults without immune deficiencies in 95% cases ends up with autorecovery. And acute hepatitis C in 60-85% cases becomes chronic.

Q: How to know from test results whether treatment is needed or not?

A: Any type of hepatitis reqiures treatment if liver damage is significant. Biochemical test and biopsy, which detects fibrosis (when liver cells are replaced with connective tissue), will show it. In hepatitis B are taken into account viral loads – the more virus is in blood, the more probability is for the disease to progress.

When viral load is low and bioorganics indicators are normal, you may live in security and once a year undergo examination. Remember that in this period you may infect people around you via blood or sexual intercource that is why your relatives should vaccinate. The effectiveness of vaccination is 98%.

Q: What are the treatments for chronic hepatitis?

A: Hepatitis C may be treated with interferon alfa and ribavirin. Hepatitis B may be ctreated with interferon alfa or nucleoside analogues that are build into virus structure preventing it from reproduction. However, small persentage of patients get recovered from hepatitis B. Stopping virus reproduction helps to reduce significantly probability of complications.

Q: Are there any false-positive test results for hepatitis?

A: Yes, only in case of mistakes in the laboratory. In order to avoid such results, in good laboratories is made additionally check analysis.

Hepatitis Glossary

Antibodies are protective proteins which produce our immune cells in reply to contacting with virus antigenes.

Antigens are particles of the virus.

Viral hepatitis is hepatitis caused by a viral infection.

Hepatitis is an inflammation of the liver tissue.

Polymerase chain reaction (PCR) is a high-strung test which allows to detect in the blood genetic material of the virus (its DNA or RNA). PCR detects virus in blood in 10 days after infection.

Viral load is the amount of virus in 1 ml of blood.

Additional examinations

1. Ultrasonic examination not detects hepatitis but at the stage of cirrhosis it shows first signs of changes. By the way, large liver mass is not a sign of hepatitis.
2. Genotyping is an examination of virus for the choice of treatment strategy. Different genotypes of virus C are treated with different effectiveness. Detecting of genotypes of virus B has no impact on the treatment effectiveness.
3. Liver biopsy detects the degree of inflammation. This is required when other analysis are not clear.

What Is Hepatitis?

A person may catch hepatitis and recover from it, not even knowing about it. A person may live with chronic form of hepatitis many years and discover it when the disease is on cirrhosis stage.

What viruses cause hepatitis?

Viruses A and E may cause acute hepatitis called “the disease of dirty hands” because people often get infection while traveling in the African and Asian countries. Viruses B, C, D may be agents of chronic hepatitis. Those viruses are transmitted via blood or during unprotected sex. In some cases chronic viral hepatitis after 10-30 years may lead to cirrhosis or liver cancer.

What are hepatitis symptoms?Acute hepatitis has the same symptoms as simple cold with food infection symptoms। In case yellow plague is not developed, people often recover successfully without knowing what disease they had। So acute hepatitis C in 95% of cases is unnoticed and hepatitis B is unnoticed in 70%. The main symptom showing chronic form of disease is constant fatigue.

Who and when should make tests for hepatitis?
# patients with chronic kidney failure who are on hemodialysis
# persons after operations and endoscopic procedures
# spouses and children of persons with hepatitis
# if the blood biochemical test shows liver damage
# drug addicts
# after unprotected sexual intercourse
# after making tattoo, piercing, manicure or pedicure in salon
# after visiting countries with high prevalence of hepatitis: South-East Asia, Central Africa

What tests should be made at the first suspicion?

To detect hepatitis, biochemical test of blood is made. This test is cheap, informative and available in most laboratories. The most important indicators for the diagnosis of hepatitis is the level of enzymes SPGT (alanine aminotransferase) and ACT (aspartate aminotransferase). In case they are out of normal level then it means the patient has hepatitis. Then the next step is to go to gastroenterologist and infectiologist that do specialize on hepatitis.

How to check for hepatitis B and C?

The most rational way is to do a blood test on the most important markers of chronic hepatitis B and C. In case were found HbsAg (membrane antigen of B virus) and antibodies to to hepatitis C virus, you should go to the doctor. He will say if it is necessary or not to make other tests to detect virus antigens. Such profound examinations are made in special laboratories. You may at once make blood test for RNA and DNA of viruses B and C. If they will be detected then you should anyway make antigen and antibodies test in order to find the best treatment.

How To Improve Your Immunity?

In autumn, winter and spring many of us complain on immunity lowering. We become more vulnerable to different diseases and we may catch any virus.


First of all, what is immunity?
Immunity is body resistance to everything heterogenes. Immune system protects body from penetration of dangerous for its life activity matters such as bacteria, viruses and fungi and other harmful micro organisms.

If infection enters human body, then infection starts to reproduce and human condition breaks down. Do appear first symptoms: sneeze, cough, high body temperature. If a person has good immunity then comes breaking point and in the blood start to produce antibodies – matters that destroy infection in the body.

Humans have special cells called lymphocytes. They act as soldiers protecting their state, in other words, they along with antibodies destroy infection acting as aggressors.
There exists species immunity when cats and dogs do not get infected with human diseases and vise versa.

Natural acquired immunity appears after past disease. Artificial immunity appears after flu shot. Everybody know that some people get diseased frequently and some quite rarely. That's a shame. So what to do?

The answer is quite simple – it is necessary to improve your immunity. It is not so difficult as it seems at first sight, although it requires some efforts. Alcohol, smoking, stress, poor ecology, unhealthy food and water, great mental and physical stress do lower immunity.

For most of us it is much easier to take a modern pill than to come down the sofa. Today modern human moves less and less, because civilization brings him a number of things literally on the plate. That is why those who want to iimprove their immunity should increase their physical activity. It may be gymnastics, aerobics, swimming. outdoor games, working in the garden, walking.

Quenching and yoga help in immunity strengthening. Healthy foods (fruits, vegetables, cereals, coarse bread, legumes, vegetable oils, honey, lactate products) also help to increase immunity. Vitamins should always be presented in your diet. Make your habit to drink vitaminic mineral assemblage. It is healthful to take each morning a spoon with honey when your stomach is empty.

Green tea and mate positively work on the immunity. Stress usually is resulted from overfatigue that is why you should rest good. So, you will reduce chances to get infected. And in case you get infected, you will recover from disease much easily. It is better to improve immunity in late spring, summer and early autumn.

Genital Herpes

Genital herpes is caused by the agent called herpes simplex virus (HSV). There are two types of herpes virus:

I herpes virus type affects mainly skin and mucous coat of lips, eyes, nose (HSV-1)

II herpes virus type affects mucous coat of genital organs (HSV-2)

However, genital herpes may be developed under the influence of mixed infection of type I and type II.

Ways of transmission:
1. sexual contact with someone who has a genital HSV-2 infection;
2. genital oral contact;
3. autoinfection, when diseased person carries the virus from center of infection on uninfected parts of the body, for example, from face to genital organs;
4. vertical way of transmission is possible when during pregnancy occurs infection of baby from his mother (fetal infection) or during childbirth
5. domestic mode of transmission occurs extremely rarely and is completely excluded if the virus containing the secret dries.

The main source of infection in men is the urogenital tract, and in women - cervical canal.

Course

Infection with the herpes virus does not always cause manifestation of the disease, often it may have hidden character. In this case people do not know they have this virus disease, so they become source of infection for their sexual partner. A characteristic feature of herpes infection is duration of staying of the virus in the body (herpes virus may stay in the body whole life) and predisposition to aggravation. Undercooling, stress, overfatigue, infective disease (influenza, sore throat, respiratory viral infection) may cause aggravation of herpes.

Common manifestation: high temperature, headache, muscle pain, nausea.

Local manifestations occur in vulva area, vesical cervix area, urine. Typical sign is appearing of numerous small bladders with liquid, redness and edema of affected areas. When those bladders do burst, on their spots appear sores which do heal during 2-3 weeks. Along with bladder eruption and sore appearing patient can experience itch, pain, burning, lower abdomen severity.

Diagnostics of herpes infection is based on detecting the virus and its antibodies in the blood and in swabs from affected area.

Genital Herpes Treatment

Treatment takes quite long time. Genital herpes treatment is directed on stoppage of virus reproduction in human body and elevation of body defenses. Remedies acting directly on virus are not still found. Doctors prescribe such medications as Zovirax (Aciclovir), Neovir, specific zoster immunoglobulin. Ointments are used to shorten time for sores healing on affected areas.

In order to rise immunity doctors prescribe immunostimulants and vitamin and mineral complexes.

Taking Zovirax (Aciclovir) during several months helps to prevent recurrence of genital herpes.

Complications caused by herpes virus during pregnancy:

# prematurity or premature birth
# development of fetus abnormalities
# transplacental infection

Swine Flu. Part Two

Should women stop breastfeeding if they do think they might have swine flu H1N1?

No, they should continue breastfeeding unless doctor advises them to stop. Continuing breastfeeding protects baby from getting infected by passing on maternal antibodies and boosting the immune system.

Should I take an antiviral drug in order to prevent swine flu H1N1?

No, you should not take antiviral drugs unless prescribed by the doctor.

Should I avoid traveling to flu affected countries?

Some health ministries have advised the public to avoid unnecessary travel to flu affected countries. But the World Health Organization is not recommending travel restrictions because international travel will disrupt people's plans and schedules with little impact on the spread of the virus.

May I go to the work if I have swine flu H1N1?

No, it is recommended to stay at home if you have symptoms of swine flu. This is important to protect your friends and colleagues from becoming ill.

What is the treatment of swine flu H1N1?

Swine flu is responding to two antiviral drugs called oseltamivir or zanamivir. These are prescription drugs that stop the flu virus from reproducing in your body. Antiviral drugs can make you feel better faster. They may also prevent serious flu complications.

Can I travel if I have swine flu H1N1?

If you have symptoms of swine flu, you should not travel. If you feel bad but cannot avoid traveling or contact with others, cover your mouth and nose with special mask.

What is the incubation period of swine flu H1N1?

The incubation period of swine flu is unknown but it could range from 1 to 7 days, and more likely 1 to 4 days.

WHO has declared a swine flu H1N1 pandemic. What does that mean?

A pandemic is an infectious disease that is spreading worldwide. If a disease is declared a pandemic, it means that it is spreading rapidly across the world. When the WHO declared a swine flu H1N1 pandemic, the flu virus had already been reported from 70 countries and cases were occurring in multiple parts of the world.

How long does influenza virus remain alive on surfaces such as tables and doorknobs?

Influenza virus can survive on environmental surfaces and can infect a person for up to 2-8 hours after being deposited on the surface.

Bacteria: Advantages:

Bacteria are our friends as they are associated with several advantages in various forms. Some of them are:

1. Bacteria & Ecosystem: Saprophytic bacteria along with saprophytic fungi perform useful role of decomposers in ecosystem. Decomposition of organic matter in absence of O₂ is called putrefaction and breakdown of organic matter in presence of O₂ is called decay. Highly un-decomposed organic matter is litter; partly decomposed organic matter is humus and highly decomposed organic matter is called humus.
2. Bacteria & Industry: Lactobacillus laciti and Streptococcus lacti convert milk into curd. Acetobacillus aciti changes sugar solution into vinegar. Flavour in tea leaves by Micococcus condensa and in tobacco leaves by Micococus megatherium develops due to fermentation activity of bacteria. Retting involves separation of plant fibers after decomposition of non-cellulosic materials by various species of Closteridium like C.butyricum and C.felsineum.
3. Bacteria and N-cycle system: Nitrogen is first essential element in terms of requirement for proper growth of plants. It is required in protein synthesis, chlorophyll synthesis and also in synthesis of nucleic acids. Plants cannot utilize molecular nitrogen directly. The plants mainly in the form of nitrates absorb it. Nitrogen changes into nitrate via ammonia formation. Some bacteria control N-cycle, which comprises Nitrogen fixation, Nitrification and Denitrification. Nitrogen fixation involves conversion of N₂ into ammonia. Bacteria which participate in N-fixation are Closteridium, Azotobacter and Rhizobium etc. Closteridium and Azotobacter and asymbiotic biological N fixing bacteria whereas Rhizobium is symbiotic biological N-fixing bacteria are present in root nodules of Leguminous or papilionaceous plants. Klebsiella is leaf nodule N-fixing bacteria. Frankia is non-leguminous N-fixing bacteria 'nif' genes control biological N-fixation. Mechanism of biological N-fixation by bacteria was first studied by Heijerinck whereas Winogradasky studied biological N₂ fixation by some blue green algae.
   • Conversion of NH₃ into nitrite is termed as initial stage of Nitrification. A bacterium which participates in initial stage of nitrification is nitrosomonas Conversions of nitrite into nitrate is called final stage of nitrification. Nitrobacter is the bacteria which participates in final stage of nitrification.
   • Release of Nitrogen from Macromolecules of Nitrogen is called denitrification. Bacillus denitrificans is the bacteria involved in denitrification. The summary of Nitrogen cycle is given in the following figure:

Summary of various N-fixing bacteria:

• Azotobacter, Thiobacillus, Mycobacterium etc. : Free living & aerobic.
• Closteridium Klebsiella : Free living & anaerobic.
• Rhizobium, Aopzprirllium Frankia : Symbiotic & anaerobic
• Citrobacter : Symbiotic and anaerobic
  • Bacteria & Antibiotics: Though first antibiotic penicillin was obtained from ascomycetes fungus Penicillium notatum by Alexander Flemming in 1929, yet soil-borne bacteria Streptomyces of actinomycetes (ray fungi) are rich source of various types of antibioitics. Antibiotics are chemical inhibition. The term 'antibiotic' was coined by Salman Waksman. Antibiotics are known as chemotherapeutic agents. Some of the antibiotics extracted from bacteria are bacitracin, subtilin, polymyxin, gramicidin etc.

Salient features of some antibiotics chemotherapeutic agents

Name of the antibiotics	Name of the discover	Source of antibiotics	Action of antibiotics
Penicillin	Alexander Flemming	P. notatum P. chrysogenum	Breaks muco complex cell wall of bacteria.
Streptomycin	Waksman	Streptomyces griesus	Inhibits synthesis of 30S fragment of ribosome in bacteria.
Erythromycin	Mc Guire	S. erythreus	Inhibits synthesis of 50S fragment of ribosome in bacteria
Chloromycin	Burkholder	S. venezualae	Inhibits initiation of protein synthesis in bacteria.
Aureomycin	Duggar	S. auerofaciens	Inhibits formation of tRNA amino acid complex.
Terramycin	Pfizer Ltd.	S. rimosus	Inhibits formation of tRNA amino acid complex.

Penicillin is not broad spectrum antibiotic because it is more active on gram positive bacteria, less effective on gram negative bacteria. Streptomycin is first brad spectrum antibiotic which is equally active on gram positive and gram negative bacteria both.

• Bacteria & Miscellaneous uses

1. Aerobacter aerogenes decomposes DDT whereas Flavobacterium and Corynebacterium decompose 2, 4-D etc. DDT and 2, 4-D are non-biodegradable chemicals, which may be lethal even.

2. Bacillus pudita, pseudomonas and some other oil-eating bacteria help in cleaning up oil spills. They thus help in preventing water pollution of seas/oceans caused due to oil refineries.
3. Anand Mohan Chakroborty has developed genetically engineered bacteria named Superbug that feeds on oil spills.
4. Bacterium Methylophylus methylotropous is source of single cell protein (SCP) the product was called 'Pruteen'. Fungus Fusarium is also used for the purpose i.e. preparation of mycoprotein on larger scale.
5. Batch culture & continuous culture are two main methods of fermentation on larger scale. The former is closed system whereas latter is open system.

Bacteria: Disadvantages

• Bacteria are our 'foes' as they are associated with several diseases of plants and animals including man due to parasitic mode of nutrition of some bacteria. Bacterial attack is less severe on plants than it is on animals.
• Important bacterial diseases on plants are:
  1. Canker of Citrus (citrus canker) Xanthomonas citri
  2. Angular leaf spot of cotton X. malvacearum
  3. Fire blight of apples Erwinnia amylovora
  4. Crown gall of crops Agrobacterium tumefaciens
  5. Tondu of wheat Corynebacterium tritici
     • Important bacterial diseases on man are:
  6. Cyphillis Tryponema pallidum
  7. Plague (Black Death) Pasteurella pestis (Y. pestis)
  8. Chlorea Vibrio cholerae
  9. Anthrax Bacillus anthracis
  10. Pneumonia Diplococcus pneumonae
  11. Tuberculosis (TB) Mycobacterium tuberculoses
  12. Typhoid (Enteric fever) Salmonella typhi
  13. Bacterial dysentery Bacillus dysentrae (Shigella)
  14. Amoeboid dysentery Entamoeba histolytica (Protozoa)
  15. Tetanus (Lock jaw) Closteridium tetani
  16. Ptomaine (deadly food poisoning) Closteridium botulinum
  17. Leprosy Bacillus lepri (Mycobacterium lepri)
  18. Diptheria Corynebacterium diptherae
  19. Erysepalas (deadly blood Streptococcus

Poisoning; Death of RBC's)

20. Whooping cough Bordetella partusis
21. Gonorrhoea Neisseria gonorrhoae

Bacterial diseases like cholera, typhoid, dysentery etc are water borne diseases: tuberculosis, plague etc are air-borne diseases whereas disease like tetanus spreads through wounds. Syphilis is transmitted through sexual contact. Transmission of leprosy through contact is a matter of dispute. India based Mother Teresa was awarded Nobel Prize for her service to leprosy patients in West Bengal and other parts of India

Bacteria : Forms

1. On the basis of shape, bacteria may be cocci (Singular coccus), Bacilli (Bacillus), Vibrio, Spirillum etc. Cocci are spherical bacteria, smallest in size. They may be single (monoococucus), in pairs (Diplococcus), in chains (streptococcus), in bunches (staphylococcus) or cuboid (sar cinnae). Bacteria causing pneumonia are Diplococcus Bacilli are rod shaped bacteria they may be single or in chains (Streptobacilli). Majority of parasitic bacteria are rod shaped bacteria. Streptobacilli surrounded by mucilaginous sheath form Zoogloea. Vibro are comma shaped bacteria. Bacteria causing cholera are vibrio bacteria. Spirillum and spirochaete are zigzag spring like bacteria, Spirillum volutans is recognized as largest bacteria. The terms like coccus, bacillus, vibrio etc were coined by Mueller.
2. On the basis of cilia, a bacterial cell may be:

Atrichous : Bacterial cell without cilia.

Monotrichour : Bacteria cell with single cilia.

Lopotrichous : Bacteria cell with tuft of cilia at one end.

Cephalotrichous : Bacterial cell with tuft of cilia at both the ends.

Amphitrichous : Bacterial cell with one cilia at both the ends.

Peritrichous : Bacterial cell with cilia throughout the body.

Bacteria causing cholera disease is comma shaped & Lophotrichous.

3. On the basis of nutrition, bacteria may heterotrophy or autotroph. Heterotroph bacteria are further divided as saprophytic bacteria & parasitic bacteria. Similarly, autotroph bacteria are further divided as chemosynthetic and photosynthetic bacteria.
   • Bacteria, which obtain their food from dead organic matter, are saprophytic bacteria. They perform significant role of decomposers in ecosystem. Bacteria, which obtain their food from other living entity, are called parasitic bacteria. The living entity, which provides food to parasite, is termed as host. Host-parasite relation is specific. Parasite is called pathogen when it spreads in host.
   • Bacteria, which obtain their food through the inorganic reactions in which they participate, are called chemosynthetic bacteria. They are named after the inorganic reactions, us that they are involved. Thus, N-Bacteria S-Bacteria & Fe-Bacteria etc are examples of chemosynthetic bacteria. Chemosynthetic bacteria are basically autotroph but do not require pigment chlorophyll for energy requirement. Chemosynthetic bacteria will survive alone if chlorophyll pigment disappears from the world; rest will perish.
   • Bacteria, which obtain chemical energy through glucose formation, are called photosynthetic bacteria. They are autotrophs and depend on chlorophyll like pigments i.e., Bacteriochlorophyll & chlorobium chlorophyll (Bacterio viridies) for glucose formation. Green-S-Bacteria, Purple-S-Bacteria & Rhodospirillium etc. are examples of photosynthetic bacteria.

Comparison between normal and bacterial photosynthesis
Normal Photosynthesis	Bacterial Photosynthesis
1. Raw materials are CO2 & H2O	1. Raw materials are CO2 & H2S
2. H for reduction of CO2 into glucose comes from H2O	2. H- for reduction of CO2 into glucose comes from H2S.
3. Principal pigment is chlorophyll a	3. Principal pigment Bacteriochlorophyll a.
4. Intermediate H-acceptor is NADP	4. Intermediate H-acceptor is NAD.
5. PS I & PS II both are present in light phase.	5. PS I only is present in light phase; PS II is absent.
6. O2 is released as by product	6. S is released as by product
7. Biochemical reaction 6CO2 + 12H2O = C6H12O6+6H2O+6O2	7. Biochemical reaction. 6CO2 + 12H2O = C6H12O6+6H2O+12S
Generalised equation for both of the above 6CO2 + 12H2A = C6H12O6 + 6H2O + 12A A may be oxygen or sulfur.

Photosynthesis in bacteria was first studied by Van Neil of Germany who was first to support the idea of Robino Hill that O₂ released in normal photosynthesis comes from H₂O and not from CO₂.

Bacteria: Introduction

1. Study of Bacteria is called 'Bacteriology'. Leeuwenhoek is recognized as pioneer worker in Bacteriology. Pasteur, Koch & Lister are other earlier workers in Bacteriology.
2. The term bacteria were coined by Ehrenberg for the smaller 'animalcules' or the 'wretched beasts' of Leeuwenhoek. Bacteria are found everywhere and in all sorts of climates however they do not survive in acidic medium of Pickle solution or highly concentrated sucrose solution due to plasmolysis.
3. Bacteria activity is reduced greatly at low temperature; this explains why foodstuff remains safe for longer period in cold devices like fridge and refrigerators etc. Bacteria behave in different manner in different range of temperature.

Natural Defenses against Viral Infections:

1. Interferons (Isaacs and Lindenmann, 1957). Interferons are antiviral proteins (a class of glycoproteins) which diffuse out from infected cells, enter into the cells in the neighbourhood and impart a defense mechanism to these cells against viral infections by inhibiting the synthesis of viral proteins. These are therefore used for therapeutic and preventive purposes in viral infections, interferons are always secreted by host cells against viral infection.

2. Body Immunity. Viruses are good antigens to induce active production of specific antibodies (by lymphocytes).

3. Immunoprophylaxis – Vaccines: Vaccines contain inactivated (attenuated) virions, which cannot cause the concerned diseases, but still act as antigens to induce antibody production by the immune system of the body.

4. Chemotherapy – Antiviral Drugs: The chemotherapeutic agents antibiotics which are used in the treatment and control of bacterial diseases are ineffective for viral diseases. However, some antiviral drugs have been prepared. These include (i) Thiosemicarbozone (for treatment and prevention of smallpox), (ii) Ribavirin or Virozole (for influenza),
(iii) Deoxyuridines, Acylovir (for herpes), (iv) Foscarnet (for hepatitis-B) etc.

2g) Viruses: Study of Bacteriophages

1. Discovery of bacteriophages is associated with Twort when he reported viral disease in bacteria. The term bacteriophages was coined by De Herelle. They are viruses, which attack bacteria. A typical bacteriophage looks like a tadpole/sperm comprising a hexagonal head of protein and a tail also a protein they show binal symmetry. Head is 1000A long and 650A in width; length of the tail is 1000A. Thus, head and tail are equal in length. Infective part of the bacteriophage in most of the cases is ds-linear DNA and it is present in hexagonal head. Joint of head and tails is neck, which is covered by collar of protein. Tail ends in end plate that develops 3 pairs of tail fibers of protein. Bacteriophages that attack E.coli are called coliphage or T-phages. They were numbered as T₁, T₂, T₃, T₄, T₅, T₆, T₇ etc by Delburck, T₂, T₄, T₆ etc are T-even phages T₁, T₃, T₅, etc or T-odd phages.
2. A bacteriophage comes into contact with the bacterial (host) cell through tail fibres. A passage is created in the host cell once the mucocomplex cell wall of bacteria is broken by lysozyme of bacteriophage. Once the passage is created, ds-linear DNA of bacteriophage is dropped inside the host cell. Empty protein coat i.e. Ghost protein remains out the host cell and disappears later on. Infective part or genetic material in ÆX174 phages is ss circular DNA and it is RNA in MS-2 & R17 phages.
3. Phage DNA dropped inside host cell may be virulent or temperate. Bacterial cell is destroyed if phage DNA is virulent, bacterial cell is not destroyed is phage DNA is temperate.
4. Destruction of bacterial cell by virulent phage DNA is called lysis. The sequence of events leading to lysis of bacterial cell are:
   • Virulent phage DNA dropped inside bacterial cell.
   • Multiplication of phage DNA inside host cell i.e. Formation of prophage. Formation of complete phages. (End of latent period or period of eclipse of phages).
   • Destruction or lysis of bacterial cell (Total time: 15-20 minutes).*
5. A bacterial cell is not destroyed if phage DNA is temperate. Temperate phage DNA is attached with host DNA; this is called lysogeny. A lysogenic bacterial cell behaves normally till temperate phage DNA is attached. Lysogeny in bacteria was first reported by Lwoff. Lwoff also coined the term l-phage for those phages in which tail terminates into single tail fibre.
   • Lysogeny may be of 3 types. They are l-phage lysogeny; P₁-phage lysogeny and mu-phage lysogeny. In l-phage lysogeny, temperate phage DNA is attached with bacterial DNA at specific place i.e. at 'gal' & 'bio' genes of bacterial DNA. In P₁-phage lysogeny, temperate phage DNA is attached with any place other than gal's genes. In mu-phage lysogeny, temperate phage DNA is never attached with bacterial DNA, remain in bacterial cytoplasm as plasmid.
   • A lysogenic bacterial cell shows different behaviour when exposed to different dosages of UV rays:

Some Important Modern Viral Diseases

1. Cancer or Carcinoma:

Despite the fact that virus causing cancer is yet to be identified, still cancer is considered like a viral disease because of typical viral symptoms like Hyperplasia & hypertrophy, are reported in cancer. Certain genes called proto-oncogenes (c-onc) are present in human cells, which are involved in normal cell function. Mutation of proto-oncogenes may give rise to oncogenes, which stimulate cell division leading to an uncontrolled growth of the cells causing cancer. All retoveiruses and some DNA containing viruses (such as poxvirus, adenovirus, Herpes virus, hepatitis-B virus etc.) possess oncogene (v.onc) in their genome. These viruses are potential cancer producing pathogens. Study of cancer is called Oncology. Temin and Baltimore's studies on Rous sarcoma virus [RSV] have provided new dimensions in the knowledge of cancer. RSV is RNA containing virus and RNA of RSV forms DNA inside host cell through reverse transcription or 'Teminism'. Newly formed DNA develops malignant tumours in host. Harmful tumor is called malignant tumours whereas tumours, which are not harmful, are termed as benign tumours. Are lethal in advanced stage.

2. Acquired Immunodeficiency Syndrome (AIDS):

AIDS is a viral disease in which our acquired immunity defense system is gradually shattered, and the patient dies of multiple infectious diseases. The first indication of AIDS disease came to light in USA in 1981 amongst a group of young homosexuals who were addicts of herion and other narcotics. Luc Montagnier (1983) and Robert Gallo (1984) discovered that a new type of retrovirus is the causative pathogen of AIDS. In 1986, The International Committee of virus Nomenclature (ICVN) named the AIDS virus as Human Immunodeficiency Virus (HIV).

Although AIDS is hardly a two and half decades old disease, it has spread virtually all over the world, becoming pandemic. According to the estimates of world Health Organization (WHO), about 52 million people in the world harbour HIV and thousands of new cases are detected every day. In India HIV infection was first detected in 1986 in some sex workers of Tamil Nadu. Since then, about 4 million cases have been detected and infection is fast spreading.

Structure of HIV:

HIV is a spherical, enveloped virus of about 90-120 nm diameter. Its genome consists of a single stranded RNA filament segmented into two identical filaments and associated with a 'reverse transcriptase enzyme'. Due to the presence of two identical filaments of RNA, HIV is considered to be 'diploid'. The envelope is comprised of a lipid bilayer derived from host cell membrane, and projecting, knob like glycoprotein spikes with pedicels formed of virus coded glycol-proteins (gp).

Pathogenesis and Symptoms:

The sentinels of our defense system are a type of white blood cells called lymphocytes. These cells are of different types to play different roles in acquired immunity. One type of lymphocytes called T₄(T_H) lymphocytes, play the crucial role in activation of other components of the immune system and production of antibodies. HIV attacks T₄ lymphocytes and destroy them. As a result the T₄ lymphocyte count in blood gradually diminishes (<>4 lymphocytes through several years ultimately leads to a full blown AIDS disease, during which a patient suffers from persistent fever and diarrhea, loss of appetite and weight, weakness and fatique, body pain, dry cough, white lesions in mouth and alimentary canal and warts upon anus and genitals. Eventually, the patient loses immunity and dies of multiple infectious diseases.

Transmission:

HIV is present in blood and other body fluids of infected persons. Hence it is transmitted from one to another person through activities involving exchange or transfer of body fluids. Thus, HIV is primarily transmitted through sexual activities. Unprotected sex, sharing of syringes and needles by intravenous drug addicts, use of unsterilized syringes by doctors and health workers etc. are responsible for transmission of HIV. Transfusion of infected blood and blood products, transplantations from infected to healthy one through breast milk feeding after birth are the other potential mode of transmission of HIV.

Diagnosis:

Some genes of HIV genome code for synthesis of some antigens which are released into the blood by infected T₄ lymphocytes. The immune system of body produces antibodies against these antigens, which can be detected by serological test called Elisa (Enzyme Linked Immunosorbent Assay), western blotting and PCR polymerase reaction test are the confirmatory test.

Symbol used to describe AIDS disease is ' ' (red ribbon). Noted Hollywood star Rock Hudson & Lawn Tennis Player Arthur Ashe of US were notable AIDS-causalities.

NARI (National AIDS Research Institute Puna).

NACO (National AIDS Control Organisation).

ARV (Anti Retro Viral Drug).

Prevention and Treatment:

General precautions such as safer sex and extensive use of condoms, strict screening of blood and blood products used for transfusions and tissue and organ transplantations, and extensive health education can prevent AIDS. December, 1 is observed as World's AIDS Day to arouse general awareness amongst people about HIV infection.

At present, there is no effective drug to save the immune system of AIDS patient from collapse. However, there are some drugs which are known to delay the progress of AIDS. These include Zidovudine (Azidothymidine-AZT), XQ-9302, Amphotericine-B and its methyl ester etc.

3. Pox:

Following types of pox diseases are reported in man:

Small Pox : Caused by DNA containing Pox viridae, Varoila.

Chicken Pox : Caused by DNA containing Herpes Virus, Vacicella.

German Pox : Caused by RNA containing Para influenza virus, Rubella.

Measles or Khasra : Caused by RNA containing Para influenza virus or Paramyxoviridae with minus strand RNA. AS already mentioned, vaccines of small pox were prepared by Jenner. Earlier small pox was very lethal disease in epidemic form in India. Officially, it has been eradicated from India with the help of WHO

MICROBIOLOGY: STUDY OF VIRUSES

2a) Viruses: Introduction

1. Study of viruses is called virology and Beijerinck is recognized as 'father of virology'. He reported enormous power of multiplication of viruses inside host cell. He also studied mechanism of nitrogen fixation by microorganisms like bacteria.
2. The term 'virus' has been derived from Greek word 'virion' which means 'poison'. Viruses are defined as hyperparasites and 'filterable entities' not having any cellular organization and defined as hyperparasites and 'filterable entities' not having any cellular organization and because of this cell theory is not applicable on them. They are thus exceptions to cell theory. They form crystals when taken out of the host cell. This shows non-living nature of viruses, which was first revealed by Stanley while working on 'Tobacco Mosaic Virus'. Nucleoprotein structure of viruses was first studied by Bawden & Pierre. In nucleoprotein structure of viruses, core of nucleic acid is surrounded by coat of protein. Viruses are unique as they contain only one type of nucleic acid. Mutation in viruses was first reported by Delbruck. Mutation and enormous power of reproduction confirm living nature of viruses. Viruses are thus the only entities, which have characters of non-living and living entities both. They are thus 'connecting links' between non-living entities and lining entities.

2b) Viruses: Historical Studies

Studies in viruses started with independent works of Pasteur and Adolf Mayer. Pasteur prepared vaccines of rabies virus and used the term 'virus' for first time. Mayer reported mosaic like spots on leaves of tobacco plant infected with virus. He described the virus as Tobacco Mosaic Virus [TMV]. Ivanowski passed the cell sap of infected tobacco leaves through bacteria proof bacteria proof filter and sprayed the filtrate on healthy leaves. Mosaic spots appeared again. Ivanowski through his experiment described viruses as filterable entities. Famous conclusion of Beijerinck about viruses i.e. 'contagium vivum fluidum' means sap retains the infection of viruses (living fluid infectant). Takami of Holland studied transmission of viruses through various agencies. He observed that insects are important agencies in transmission of viruses. Insects that transmit viruses are called 'vertors'. Viruses-vector relationship is highly specific.

Culture of viruses was prepared for the first time by Ender. It was poliomyelitis virus. Hershey and Chase observed that nucleic acid is the infective part of virus. They selected Bacteriophages for their experiment. Bacteriophages are DNA containing viruses which attack bacteria. They were discovered by Twort; further studies were made by DeHerelle. Experiment of Hershey & Chase is another example which confirms status of DNA as genetic material. Safferman & Morris discovered 'Cyanophages' i.e., viruses which attack blue green algae like Lyngbya, Phormidium & Plectonema. They are also called LPP-1 on the basis of hosts. Mycophages were discovered by Sinoten. They contain ds RNA.

Issac & Lindeman discovered a protein called Interferon secreted by host cells against infection of viruses. They selected cold virus for their experiment. Gibbs described viruses in coded form which is called 'Cryptogram of viruses' Cryptogram of viruses is based on 4 pairs of characters:

First pair : Type of nucleic acid in virus i.e. R or D

Number of thread in nucleic acid 1 or 2

Second pair : Molecular weight of viruses in millions i.e. 2

Percentage of nucleic acid of the viruses 5

Third pair : Shape of the virus in total i.e. E (elongeted) or S (spiral) or

X (unknown)

Shape of the protein coat of the virus E or S or X

(E' means elongated structure or rod shaped structure with blunt ends)

Fourth pair : Host/vector i.e. S (seed plant), I(invertebrate), V(vertebrate),

B(bacterium), Fu(fungus), Di(diptra), Af(aphid), Zero or 0 (novector),

X(unknown vector) Vector of the virus X

Thus, for example R/1; 2/5; E/E; S/X is cryptogram of TMV.

For Polia Virus (Poliovirus Primus) cryptogram is R/1; 5/30; S/S; V/O.

For Influenza Virus (mixovirus influenzae) R/1; 2-3/10; S/E; V/O.

For T4 phage D/2; 130/40; X/X; B/O.

2c) Viruses: Some Terms

1. A complete virus having a core of nucleic acid and coat of protein is called virion. Protein coat of the virus is termed as capsid; units of capsid are capsomeres. A virus drops its infective part i.e., nucleic acid alone inside host cell; empty protein coat remains outside. This empty protein coat, which remains outside the host called ghost protein, disappears later on. Raw material for new protein coat of the progeny viruses is contributed by the host.

Þ A few proteins in some viruses are enzymatic in functions e.g. lysozyme in bacteriophages, reverse transcriptase(RNA dependent DNA polymerase) in retrovituses, neuraminidase in influenza virus etc.

2. Viriod: Subviral agent having infectious nucleic acid alone is called viroid. Viroids are RNA & particles lacks protein coat. Spindle disease in photo tuber is caused by viroid, which is PSTV. Viroids were discovered by Diener & Rayner.
3. Prion or Slow Virus: Protein macromolecules causing infections are called prions. They lack ucleic acids. Scrappes & Kuru diseases (Severe brain infection) is sheep are caused by prions. They were first reported by Priusner who was awarded Nobel Prize for reporting Mad Cow disease caused by PrP (prion related protein). Bovine spongiform encephalopathy or Creulzfeldt Jacob disease (a type of insanity in young people), Kuru disease (the laughing death), Alzheimer's disease are caused by prions. In 1976 D.C.Gujdusek was awarded Nobel Prize for his work on prion based diseases.
4. Viruses transmitted by insects are called Arboviruses. Viruses causing Dengue, encephalitis etc are arboviruses.
5. Viruses which contain ss-DNA are called 'Gemini viruses'. ÆX174 phages are geminiviruses. They were reported by Sinsheimer.
6. Viruses which enter inside host cell as intact structures, are called Adeno viruses. Well defined protein coat is absent in Adenoviruses.
7. Virusoids or Satellilte RNAs (Rundle et. Al 1981). These are small circular RNAs similar to viroids, but are located inside the protein coat of a true virus. Virusoids required the assistance of virus for their replication.

2d) Viruses: Classification and Nomenclature

Earlier it was believed that plant viruses i.e. Phytophagineae contain RNA whereas animal viruses i.e. Zoophagineae contain DNA. This is, however, no more correct now. The only thing which is true about viruses is presence of only one type of nucleic acid. Cold virus i.e. Rhinovirus and poliovirus i.e. Enterovirus is together placed under Picorna virus.

2e) Viruses: Disease on Plants – Symptoms

1. Mosaic like spots may develop on leaves.
2. Leaves may show rolling or curling.
3. Leaves may show loss of chlorophyll (Chlorosis) or death of tissues (necrosis).
4. Plants may show abnormal or stunted growth.
5. Plants may show uncontrolled cell division i.e. hyperplasia(cell number increase) and unwanted swelling i.e. Hypertrophy in host.
6. Plants may show loss of entire inflorescence or flowers may become green i.e. virescence in flowers.

2f) Viruses: Some Common Viral Diseases

1. Plant Viral Diseases. Tobacco Mosaic, Potato Mosaic Pumpkin Mosaic, Apple Mosaic, Tulip Mosaic (Broken Tulip), Wheat Mosaic Streak, Bhindi Yellow Vein Mosaic, Potato Leaf Roll, Tobacco Leaf Curl, Papaya Leaf Curl. Banana Bunchy Top, Tomato Bunchy Top, Rice Tungro etc.

2. Animal Viral Diseases. Foot and Mouthm, Enquine encephalitis, Rinderpest, Kysanur Forest Disease (KFD) of monkeys (also humans), New Castle or Ranikhet of Fow].

3. Human Viral Diseases. Poliomyelitis, Rabies, Mumps, Measles, German Measles, Chickenpox, Smallpox (eradicated), Dengue, Encephalitis, Common cold, Flu, some gastrointestinal diseases, Yellow Fever, Herpes, Hepatitis, SARS, AIDS.

MICROBIOLOGY: INTRODUCTION

1. Micro-biology is study of microorganisms like viruses, Bacteria, Protozoa, 1-celled algae and 1-celled fungi etc. Antonie van Leeuwenhoek of Holland, Louis Pasteur of France, Robert Koch of Germany and Joseph Lister of England were earlier, workers in Microbiology. Leeuwenhoek is recognized as 'pioneer' worker in microbiology, he discovered bacteria for the first time as 'animalcules' or the 'wretched beastes'. Pasteur was fist to study role of microorganisms in fermentation process involved in wine preparation. Koch studied anthrax disease, caused by bacteria Bacillus anthracis. On the basis of his study Koch proposed Law of Pathogenicity, which was later on recognized as Koch's Postulates. Koch's Postulates are not applicable for viruses & organisms causing TB and leprosy. Lister introduced antiseptic surgery and also prepared culture of bacteria first time.
2. The two major research institutes of microbiology in world are: Pasteur Institute of Microbiology in Paris, France and Lister Institute of Microbiology, England. Workers at Lister Institute discovered 'naked' bacteria i.e. bacteria without cell of mucopolysaccharide complex. They were called 'L-form' of bacteria, named after Lister Institute. Mycoplasma like organisms, PPLO, is called L-form of Bacteria.
3. Triple Antigen Programme includes, immunization against Diptheria, Pertusis (Whooping cough) and Tetanus. It is also called D.P.T. Oral drops of polio are delivered separately. BCG vaccines are first vaccines given to new borns after 3-4 weeks of birth. Vaccines of: Polio was discovered by Salke; Small pox by Jenner, BCG by Calmett-Guire; Anthrax by Koch and Rabies by Pasteur. Vaccines of anthrax were prepared first. Pasteur, for developing vaccines of rabies was rewarded handsomely by Czar of Russia.

Swine Flu. Part One

Swine flu is a viral disease caused by a new type of influenza virus that has never circulated before in humans. The new virus was first detected in the USA in April 2009. The virus was initially called swine flu because it is genetically very similar to viruses that normally cause flu in swine.

Symptoms of swine flu are similar to the symptoms of seasonal flu and include fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills and fatigue. Diarrhea and vomiting have also been reported in a number of individuals.

Is swine flu H1N1 similar to seasonal flu?

Seasonal flu occurs every year but many individuals have some immunity against it which protects them from getting sick. Vaccines against seasonal flu are available in many countries. The swine flu virus on the other hand is an entirely new agent against which most of us have little or no immunity.

Is swine flu H1N1 contagious?

Yes, the virus is contagious and is spreading from person to person. It appears to be as contagious as seasonal influenza and is spreading fast among young people (from ages 10 to 45).

How does swine flu H1N1 virus spread?

Swine flu spreads from human to human in much the same way as seasonal flu. You can get infected if you inhale droplets expelled by an infected person during coughing or sneezing. Since the expelled droplets can also contaminate hands and other surfaces, you may also become infected by touching a contaminated surface and then touching your mouth or nose.

Can I get swine flu H1N1 from eating?

No, swine flu virus does not spread through food. It is safe to eat properly handled and cooked pork. The flu virus is killed by cooking temperatures of 160°F/70°C, which is commonly used for cooking meat.

How severe is the disease caused by swine flu H1N1?

The severity of disease ranges from very mild symptoms to severe diseases that can result in death. A large proportion of individuals who get infected with the virus experience mild disease and recover without hospitalization or antiviral treatment.

Who is at risk of severe swine flu disease?

Pregnant women, individuals with previously recognized medical conditions that increase the risk of flu-related complications such as asthma, diabetes, heart disease and those with weak immune systems are more likely to experience severe disease caused by flu infection.

How to protect youself and your family against swine flu H1N1?

First of all, vaccinate against A (H1N1). You can protect yourself from getting infected by avoiding close contact (minimum distance of about one meter if possible) with individuals who have flu-like symptoms. Plus, the next measures can protect you:

1. avoid crowded places or reduce the time spent in crowded places
2. improve ventilation by opening windows at home or at your job
3. avoid touching your mouth and nose
4. wash hands thoroughly with soap and water, or use an alcohol-based hand rub several times in a day
5. maintain general good heath, get adequate sleep, eat nutritious food, and stay physically active