SPACIAL AND TEMPORAL DISTRIBUTION OF DISEASES Spatial distribution

SPACIAL AND TEMPORAL DISTRIBUTION OF DISEASES Spatial distribution: Population-based distribution of diseases Temporal distribution: Time-based distribution of diseases Temporal Distribution of Diseases The temporal distribution of the diseases can be shown at the time of the calendar or at the absolute time. The distribution of disease frequency over time is analyzed under 3 headings according to the time dimension considered: 1 - Short-term 2 - Periodic 3 - Long term

SPACIAL AND TEMPORAL DISTRIBUTION OF DISEASES Short-term distribution: Sudden outbreaks cluster in a short period of time. Epidemics show short temporal distribution Periodic (cyclic) distribution: The frequency of some diseases regularly increases and decreases over certain time periods, ie fluctuates over time. The cycle in which these fluctuations are observed may be seasonal and annual, depending on the disease Seasonal distribution Increase of vector-transmitted diseases in summer IBS disease in cattle is more frequent in summer More frequent occurrence of cattle and calves during dry seasons in Africa Fungal infections seen in winter Abortive infections and neonatal septicemia More frequent occurrence of hypomagneseminin in cattle during the spring

SPACIAL AND TEMPORAL DISTRIBUTION OF DISEASES Annual distribution Distemper's disease in dogs and camylobacter infections in sheep in cities increases over 2 -3 years periods Long-term (secular) distribution: Changes that occur in disease frequency over a long period of time. The secular distribution of diseases is calculated by evaluating information obtained from past records (retrospective research) tuberculosis in Turkey in the last 50 years, the reduction in the incidence of diseases such as rabies and glanders has occurred Between 1945 and 1875, rabies cases in dogs were reduced in the United States, but increased in wild animals In recent years there has been a gradual increase in cancer and respiratory system infections

SPACIAL AND TEMPORAL DISTRIBUTION OF DISEASES The reasons for the changes in the secular distribution of diseases can be explained by reasonable assumptions Increase in cancer and respiratory system infections can be linked to environmental pollution The reduction in the frequency of some infectious diseases seems to be related to vaccination and disease eradication programs Changes in the virulence of infectious agents affect the secular distribution of diseases in the long run Recent developments in diagnostic methods have led to the discovery of many previously unidentifiable or misdiagnosed diseases (enteric campylobacter infections, Lyme disease) Absolute time disease distribution

SPACIAL AND TEMPORAL DISTRIBUTION OF DISEASES Spatial Distribution of Diseases - Factors affecting the spatial distribution of diseases include population structure, transmission routes and ecological factors - In order for a disease to be visible in a region, the susceptible animal population must be found if it is transported by diseased vectors - For an epidemic to come into contact, the number of susceptible animals must be at a certain concentration - The minimum animal density required for the formation of the epidemic is called the threshold level, which is determined by the Kendal threshold theorem - In order for the parvovirus epidemic to occur in dogs, there must be at least 12 animals in km 2

ECOLOGICAL APPROACH An ecology is called science that studies animals and plants in relation to the environment they live in When working on diseases in populations, it is necessary to know the host and its relation to the environment These relationships determine when the illnesses are seen and where they are seen The climate of a region affects the life of living animals and disease agents in that region or the life of plant-fed vectors because of the life of plants The ability of animals to obtain minerals and trace elements from food depends on the vegetation and soil structure in that area