Bacterial Diseases

Bacterial Diseases

Tuberculosis (T.B.)

Two main types are : pulmonary and extra-pulmonary (i.e., intestinal, bone, skin, meninges).

Pathogen : Mycobacterium tuberculosis, releases a toxin called tuberculin.

Transmission : Through droplet infection or direct physical contact with patient.

Incubation period : Range from few weeks to few years.

Symptoms : Depend upon the organs infected with the disease

In pulmonary infection, acute chest pain and difficulty in breathing.

Fever in evening with persistent cough and haemoptysis (sputum with blood).

Loss of weight as this bacteria breaks protein at large scale, night sweating.

Meningitis leads to coma. T.B. of spinal cord is known as Pott’s disease.

In bone infection : loss of bone weight and persistent pain.

In intestinal infection : persistent diarrhoea, indigestion.

Diagnosis:

Sputum test, X-ray of chest

Positive tuberculin test (Montoux test)

Gastric analysis

Guinea pig inoculation

Treatment:

Isolation of patient and DOTS (Directly observed treatment symptoms).

Vaccination with BCG (Bacillus Calmette Guarin).

Rich proteinous diet and complete bed rest.

24th March is observed as World T.B. Day.

Diphtheria

Acute infectious bacterial disease; common in children.

Pathogen : Corynebacterium diphtheriae; produces a strong exotoxin.

Transmission : Through droplet infection (throat discharge of patients/carriers).

Incubation period : 12 hrs. to 5 days.

Portal of entry : Through eyes, middle ear, genitalia, nasal passage; site of implantation is upper respiratory tract.

Symptoms :

Begins with mild fever, sore throat, headache and fatigue.

Epithelial necrosis caused by bacterial exotoxin.

A semisolid material oozes in the throat which forms a tough, greyish pseudomembrane that chokes the air passage causing dyspnoea.

If the infection reaches heart, it leads to rapid and fatal heart blockage.

Paralysis, albuminuria and acute circulatory failure occurs.

Diagnosis : Susceptibility to Schick test.

Treatment:

If diagnosed in early stages, the disease may be cured by antitoxin administration.

Use of antibiotics like erythromycin, penicillin etc., can provide some relief.

Membrane formation in throat requires immediate surgery.

DPT vaccine given thrice at 4 weeks intervals is helpful.

Pertussis or Whooping cough

Infectious disease of respiratory tract among children.

Pathogen : Bacillus pertussis (Bordetella pertussis).

Transmission : (i) droplet infection (nasal and throat discharges); (ii) direct contact.

Incubation period : 10-15 days

Symptoms:

Inflammation of respiratory passage, with mild fever, cold and cough (mucous).

Troublesome coughing (more during night) with whoop or loud crowing inspiration.

Vomiting may occur with or without convulsions and pneumonia.

Control:

Use of antibiotics like erythromycin, ampicillin and streptomycin.

DPT vaccination is required.

Tetanus (Lock jaw)

Acute bacterial infection, releasing toxin, tetanospasmin, patient suffers from painful rigidity of muscles of the jaw.

Causes high mortality in infants and mothers.

Pathogen : Clostridium tetani.

Transmission :

Bacteria lives in the intestine of horse and other animals; spores are present in street dust, rusted iron and objects soiled with horse dung.

Spores enter human body through open wounds and cuts on coming in contact with road dust and use of improperly sterilized surgical instruments.

Incubation period : 3-28 days.

Symptoms :

Irritability, restlessness, headache and chills, followed by backpain, debility and jaw spasm.

Stiffness of neck and jaw muscle difficulty in chewing and swallowing.

Later painful contraction of jaw (or lock jaw), spasm of chest, abdomen and spine.

Death occurs due to heart failure, suffocation or exhaustion.

Control:

It is fatal after later symptoms.

Children and infants should be immunized with DPT vaccine.

ATS (Antitetanus serum) injection should be given within 24 hrs of injury or wound.

Typhoid

Acute infectious disease of alimentary canal and blood.

Pathogen : Salmonella typhi (Gram-negative, anaerobic, flagellate bacillus)

Transmission:

Through food, milk and water contaminated with faeces either directly or through flies.

Certain humans are just carriers.

Incubation period : 1-3 weeks.

Symptoms:

Bacterial toxin causes high fever.

Lesions and ulceration of intestinal wall.

Heaemorrhagic diarrhoea.

Red rashes on upper abdomen.

Diagnosis:

Widal test; devised by Georges Fernand I. Widal (1896).

Control:

Vaccine (oral and injectible; either alone or along TAB) provides immunity for 3 years.

Antibiotics like ampicillin and chloramphenicol taken.

Cholera

Acute and highly communicable epidemic disease.

Pathogen : Vibrio cholerae

Transmission :

Spreads through vomits and stools of the patients as well as carriers.

Contamination of water, food and by direct contact.

Epidemic outbreak may occur in unhygienic conditions followed by flood and other natural calamities.

Incubation period : Varies from a few hours to five days.

Symptoms:

Acute diarrhoea with copious watery stool, vomiting, rapid dehydration, muscular cramps and anuria.

Control

Prevention involves rigorous sanitation, use of food and water after heating or boiling, chlorination of water and vaccination.

Immunisation is effective for short duration of six months.

Use of antibiotics like chloramphenicol.

Patients provided with saline drips which help to retain water in the body and selective transport of sodium ions through plasma membrane.

Leprosy (Hansen’s disease)

Slow progressing chronic infectious disease of skin; non-fatal and curable, first observed by G.A. Hansen.

Only 15-20% of patients are infectious.

Pathogen:Mycobacterium leprae; mainly infects Schwann cells, perineural cells in areas which tend to remain cool.

Transmission :

Through respiratory tract or skin to skin contact.

Nasal secretion and discharge from skin lesions may have 108-109 bacilli/ml/gm.

After prolonged contact with patients.

Incubation period : Long, 3-5 years.

Symptoms :

Granulated lesions on nerves, skin, mucous membranes, bones and viscera.

Rough and scaly skin.

Damage or thickening of peripheral nerves, numbness in some parts of body and continuous fever.

Damage of nasal bone leading to collapse of nose.

Ear lobes thicken, eyebrows and eye lashes fall down.

Damage of eye due to infection of retina and cornea.

Treatment :

Earlier single drug treatment or monotherapy with dapsone was used to cure leprosy.

Now-a-days multidrug treatment (MDT) is preferred, using dapsone, rifampicin and clofazimine.

Surgery is done for reconstruction of damaged parts.

Eradication of Leprosy

National Leprosy Eradication Programme (NLEP) was launched in India in 1983.

Isolation of patients and their rehabilitation after treatment.

Creating awareness.

Botulism (Food poisoning)

Pathogen : Clostridium botulinum; their exotoxin (in the environment) is neurotoxic.

Symptoms :

Swollen tongue, double vision, vomiting, diarrhoea, fatigue and respiratory failure.

If untreated, death occur in 3-7 days.

Treatment/Control

Prevented by heating food before consumption, toxin is destroyed at 90°C for 10 minutes.

Bubonic plague (or Black death disease)

An epidemic disease spread through rats, squirrels, dogs, cats etc.

Pathogen : Yersinia pestis; a Gram-negative, rod-shaped, non-motile bacteria; multiplies in lymph nodes, especially armpits and groin.

Transmission

Vector : Rat fleas (Xenopsylla cheopis) a blood sucking insect on rat;

Death of rat is an indication of outbreak of plague;

Incubation period: 2-6 days.

Symptoms:

Swelling of lymph nodes as painful buboes.

High fever, chill, delerium, exhaustion and haemorrhages resulting in the patient turning black and finally death hence called as Black death disease.

On September 2, 1994 the bubonic plague surfaced in Maharashtra and within 3 weeks, spread to worst hit Surat (Gujarat).

Poor sanitary conditions are the main reasons for the outbreak.

Wayson stain test, used to check the susceptibility of plague.

Anthrax

Common in domesticated animals, human acquire infection through their contact.

Pathogen : Bacillus anthracis, spores remain dormant for years in the soil, used as bioweapon.

Most common form in human is cutaneous and pulmonary anthrax.

After 11^th September attack on WTC at New York (US), it became well known. Anthrax powder (spores) were sent through postal envelope.

Scarlet fever

Infection of upper respiratory tract or pharynx.

Pathogen : Streptococcus pyogenes

Incubation period : 12 to 24 hours

Symptoms:

Small rashes as “goose pimples” on the skin.

Dick test is used to determine their presence.

Meningitis

Inflammation of meninges of central nervous system caused by viruses, bacteria, fungi or protozoa.

Pathogen : Neisseria meningitidis causes meningococcal meningitis.

Pneumonia

Mostly caused by viruses or bacteria.

Pathogen : Streptococcal pneumoniae causes pneumcoccal pneumonia (bacterial pneumonia).

Other types of bacterial pneumonia are caused by

• Haemophilus influenzae
• Legionella pneumophila
• Staphylococcus aureus

Symptoms:

Fever, chills, shortness of breath and cough; inflammation of lungs.

Produce yellow-green sputum laiden with blood (occasionally).

Bacterial dysentry (Shigellosis)

Pathogen : Escherichia coli, Shigella spp, Campylobacter and Salmonella causes diarrhoeal diseases.

Bacterial dysentry is caused by Shigella including S. sonnei, S. dysenteriae, S. flexneri and S. boydii.

Transmission : Through contaminated food.

Symptoms:

Frequent passage of stool with mucus, blood and abdominal cramps.

Control

Antibiotics available.

Rehydration required.

Typhus fever

Pathogen : Rickettsia prowazekii

Transmission : From faecal matter of body lice of genus Pediculus humanus.

French scientist Charles J.H. Nicolle in 1928 got Nobel Prize for the studies on the cause and transmission of endemic typhus fever.

Gonorrhoea

Pathogen : Neisseria gonorrhae (bacteria); infects mucosal membrane (lining) of urethral or genital tract.

Symptoms

A kind of white secretion comes through the vaginal passage.

In advance stage infection spreads in upper genital parts like uterus in female and the vasa deferens in male causing sterility.

Arthritis and the degeneration of sex organs may also occur.

Syphilis

Pathogen : Treponema pallidum, the cork screw bacteria;

The effects and symptoms of disease appear in various stages.

Primary Stage

After 1-4 weeks of infection sores appears on the skin of genital organ (or also other parts of the body). Symptoms may disappear after 3-4 weeks.

Secondary Stage

Symptoms appear after 4-5 weeks

Fever, aches in different parts of the body, then disappear after 1-3 weeks.

Latent Stage

Asymptomatic; bacteria keep growing and infecting other parts of the body.

Tertiary Stage

Appears only when the vital organs of the body starts getting affected.

Damage to sex organs (ovary and testis) takes place.

In Neurosyphilis stage, nervous tissue of brain is affected.

The patients of syphilis develops characteristic spots on teeth called Hutchison’s teeth.

Congenital syphilis transmitted from mother to new-born babies.

Serological tests for early diagnosis of syphilis are:

TPI (Treponema pallidum immobilization) test.

VDRL (Venereal disease research laboratory) test

FTA-ABS (Fluorescent treponemal antibody test) and Wassermann test.

Leucorrhoea

Pathogen : Trichomonas vaginalis (protozoan); infects vaginal mucosa causing white secretion; Not much pathogenic

Gonococcal urithritis

Bacterial disease; common in male and female, non-pathogenic.

Infection occurs in urethra or urinary duct.

Symptoms pain and urinary problem.

Genital Herpes

Pathogen : Herpes simplex virus.

Symptoms : excessive pain in the penis of male and vulva of female.

In extreme condition, upper genital tract (vas deferens, fallopian tube) get affected.

Treatment :

Incurable but pain killers, compression commonly used.

Herpes simplex II causes painful blisters on the prepuce, glans penis and penile shaft in males, and on the vulva or vagina of females.

Blisters may disappear or reappear, while disease is still present in body.