Svetlana Ernstovna Mogilevtseva
Alexey Romanovich Lyashuk
Class 2.
Medical protozoology.
Flagellates(Mastigophora).
, 1. Vector-borne diseases. Natural focus of an infection, its
components.
E.N. Pavlovsky (a Russian zoologist and entomologist) developed the theory of the
natural focus of vector-borne diseases which arose at the junction of ecology,
parasitology, epidemiology and landscape geography and played a significant role in
the study of the transmission routes of parasites and infectious agents in nature.
Vector-borne diseases involve the transmission of an infectious agent through the
blood circulatory system. Vector-borne diseases include malaria, leishmaniasis,
yellow fever etc. The transmission of the infectious agent is carried out through the
bite of a blood-feeding insect, tick or mite.
,• The vector-borne transmission route Tsetse fly, the vector of the
can be of two types: causative agent of African
trypanosomiasis (sleeping sickness)
• 1) inoculation – in this case the
infection occurs when the pathogen
enters the host’s blood through the
mouth apparatus of the arthropod
directly during the bloodsucking;
Trypanosoma cruzi – the causative
• 2) contamination – in this case the agent of Chagas disease.
pathogen is excreted with the Vectors – “kissing” bugs
arthropod’s feces or in any other way Triatominae
contaminating the host’s skin and then
enters the blood stream through the
damaged skin (wounds, scratches etc.)
, According to the ways of transmission of the
infectious agent by the arthropod vector natural focus
infections are subdivided into two types:
• 1) obligate vector-borne – the transmission of
the infectious agent occurs only through the
blood-feeding arthropod during the bite;
• 2) facultative vector-borne – along with the
vector-borne transmission route other
transmission routes of the pathogen are also
possible (for example, oral, food-borne etc.)