Key Epidemiology Terms: Prevalence, Incidence, and Parasite Metrics

Prevalence

# of infected/ # total = % infected hosts (infected hosts/ total hosts * 100)

Incidence

# newly infected / # uninfected

Abundance or Density

# of parasites / # of snails

Intensity

(# parasites in 1 host)

Mean intensity

(# of parasite / # of infected shown)

Aggregated or Overdispersed

(most parasites in few hosts, most hosts = 0 or few parasites)

Parasite community

(all parasite species in one host)

Macroepidemiology

(large-scale factors disease patterns, ex. Climate, geography, culture)

Microepidemiology

(small-scale factors disease patterns, ex. Parasite strain, host genetics)

Landscape epidemiology

(environment + ecology where disease occurs, ex. Habitat, vectors, climate, hosts)

Nidus

(specific place where disease is maintained, = area with the right ecological conditions for transmission)