Biology Today — May 2017

3. Pneumonia Streptococcus pneumoniae,
   Haemophilus influenzae

Direct contact /

1    -  3    days

Cough, fever, pain in the

lungs

PCV13 vaccine /

Erythromycin, tetracycline

4. Diphtheria Corynebacterium
   diphtheriae

Droplet infection/

2-5 days

Fever, sore throat DPT vaccine /

Erythromycin

5. Whooping
   cough
   or pertussis

Bordetella pertussis Direct contact /

10   -  16   days

Cough, breathlessness

and vomiting

DPT vaccine/Erythromycin

6. Tuberculosis Mycobacterium tuberculosis Droplet infection and
   contaminated food and
   drinks / 3 - 6 weeks

Constant cough, pain

in chest, loss of weight

and appetite

BCG/Streptomycin, PAS

rifampicin

7. Tetanus
   (Lock jaw)

Clostridium tetani Spores enter the wounds

/   3    -  25   days

Painful muscular

spasms, fever, lock jaw

DPT / Antitetanus serum

(ATS), tetanus toxoid

8. Plague
   (Black
   death)

Pasteurella/Yersinia pestis Bite of infected rat flea

Xenopsylla cheopis /

2    -  6    days

Painful buboes, fever,

haemorrhages

Streptomycin, oral

tetracycline, antiplague

vaccine

9. Leprosy
   (Hansen’s
   disease)

Mycobacterium leprae Prolonged direct

contact /

2    -  5    years

Infection of skin, wasting

of body parts, deformities

of fingers, toes, hypopig-

mentation

Rifampicin, dapsone,

clofazimine

Protozoan Diseases

• Protozoans are diverse group of eukaryotic, unicellular organisms.

• Human diseases caused by protozoa are relatively few, but are individually of devastating consequences.

Malaria

• Malaria is caused by a digenetic (have two hosts to complete its life cycle) protozoan parasite known as Plasmodium.

• The primary host is female Anopheles mosquito and secondary host is man.

• Sir Ronald Ross established that malarial parasite is transmitted by the bite of a female Anopheles mosquito for which he got
Nobel Prize in 1902.

Mode of transmission

• The malarial parasite, Plasmodium enters the human body as sporozoites (infective stage) through the bite of infected female

Anopheles mosquito.

• There are four species of Plasmodium which causes four main types of malaria in human.

Benign tertian malaria

•    Caused by Plasmodium vivax.

•    Fever recurs after every   48   hours.

•    Incubation period is about     14  

days.

Quartan malaria

•    Caused by P. malariae.

•    Fever appears after every  72  

hours.

•    Incubation period is 28-30 days.

Malignant tertian malaria

•    Caused by P. falciparum.

•    Fever recurs after every   48  

hours.

•    Incubation period is   12   days.

Mild tertian malaria

•    Caused by P. ovale.

•    Fever recurs in every  48  

hours.

•    Incubation period is   14   days.

Types of malaria