This episode concludes parasitology with arthropods, organisms that either directly parasitise humans or serve as vectors for other pathogens. Drawing from Murray’s Chapter 77, it examines their dual role in disease ecology.
Arthropods include:
Ectoparasites - lice, fleas, mites, ticks
Vectors - mosquitoes, sandflies, tsetse flies
Direct infestation may cause:
Pruritus and dermatitis
Secondary bacterial infection
Hypersensitivity reactions
As vectors, arthropods transmit:
Protozoa (e.g., malaria, leishmaniasis)
Bacteria (e.g., rickettsiae, Borrelia)
Viruses (e.g., arboviruses)
Transmission can occur via salivary injection during feeding or contamination with infected faeces.
Conceptually, arthropods represent the interface between environment and host. Clinically, prevention relies heavily on environmental control and protective strategies.
Key Takeaways
Arthropods may cause direct infestation or transmit pathogens
Mosquitoes, ticks, and lice are major vectors
Vector saliva facilitates pathogen transmission
Disease prevention emphasises environmental control
Epidemiology is tightly linked to geography and climate
