This document describes the transmission of malaria, HIV/AIDS, and tuberculosis. Malaria is transmitted via the Anopheles mosquito vector and can also spread through unhygienic hospital conditions or blood transfusions. HIV is transmitted through sexual contact, blood transfusions, or from mother to child during birth or breastfeeding. Tuberculosis spreads through airborne droplets from infected individuals, especially in conditions of overcrowding, poor health, or inadequate ventilation.

1. 2.2.6. Transmission of Diseases
Learning Outcome:
Describe the causes and means of
transmission of malaria, HIV/AIDS and
TB

2. Methods of Disease Transmission
 Droplets – coughing & sneezing
 Faecal/Oral – usually from food &
drink
 Direct physical contact – touching,
kissing, sexual intercourse
 Indirect contact – touching a
contaminated object
 Vector transmission – by an insect or
other creature

3. Malaria - parasite
 Caused by a protozoan parasite of the
genus Plasmodium
 Mainly P. falciparum but other species
include P. vivax, P. ovale and P.
malariae
 P. knowlesi can cross the species
barrier from monkeys to humans
 The parasite lives in subtropical areas
of Africa, Asia and the Americas

4. ELECTRON MICROGRAPH OF PLASMODIUM PARASITE

5. RING STAGE OF PLASMODIUM FALCIPARUM

6. Spread of Malaria
 Mainly transmitted via the vector
method
 The female Anopheles mosquito feeds
nocturnally on blood
 It transfers the sporozoite phase of the
parasite from its salivary glands to the
host (mosquito saliva acts as an anti-
coagulant)
 If the host already has malaria the
mosquito sucks up the gamete stage of
the parasite
 Zygotes develop in the mosquito

7. Life Cycle of Plasmodium

8. Other means of malarial transmission
 It is also possible to spread the
parasite via unhygienic conditions
mainly in a hospital environment
 Unsterilised needles and
unscreened blood transfusions also
play a part
 The parasite can also pass across
the placenta from mother to foetus

9. HIV/AIDS cause
 Human Immunodeficiency Virus
 The virus can sit dormant for many
years (HIV Positive stage)
 Once active it destroys T helper cells
rendering the immune system
ineffective
 Then the person has Acquired Immune
Deficiency Syndrome
 Death usually soon follows due to
secondary infections

10. HIV Transmission
 Rectal, vaginal or oral sex
 Intravenous drug use – reusing
syringes
 Blood transfusions from unscreened
donors
 In Utero / Perinatal from mother to
foetus
 Breast feeding can also spread the
virus

11. Tuberculosis - Cause
 Causative agent is a rod-shaped
bacterium
 Mycobacterium tuberculosis or M.
bovis are the main species
 There are many other species that
can cause symptoms
 Over 2 billion people are infected
with TB worldwide
 Mostly the body’s immune system is
able to keep the disease at bay

13. Tuberculosis - Transmission
 Transmitted by the droplet method
 Needs prolonged contact with a carrier
or sufferer to become infected
 Infected meat or milk of cattle
 Conditions of deprivation makes
infection more likely
 Overcrowding
 Poor health or diet
 Inadequate ventilation