VPA 211: General Veterinary Parasitology and Helminthology (3+1)

TERMINOLOGIES USED IN PARASITIC DISEASES

• Epidemiology is the study of a disease in relation to the population, aspects of disease such as incidence, prevalence and transmission in a population
• Endemic disease refers to a disease that occurs with a predictable frequency with minor fluctuations in a population
• Epidemic disease refers to diseases that occur at a higher level in a place at a time than expected for the disease in the place at that particular time
• Sporadic diseases are those diseases that occurs irregularly with widely dispersed incidence or a disease that occurs infrequently
• Pandemic is an epidemic occurring in a wide/larger area.
• Incubation period is the time lapse between the entry of the parasite and the first appearance or onset of clinical signs.
• Prepatent Period is the period in which the form of the parasite is demonstrated in the clinical material of the host.
• Hypobiosis refers to temporary cessation in the development of immature stages of some nematode parasites in the host due to adverse environmental conditions, for example, Ostertagia ostertagi in cattle

• Hibernation(Winter Sleep) refers to low activity of parasites in winter.
• Aestivation (summer sleep) is the period of low activity in summer
• Diapause is aperiod of low activity in arthropods.

• Parthenogenesis is a(Virgin birth) refers to formation of progeny without fertilization e.g. Haemaphysalis ticks and Strongyloides sp. of nematodes.

• Paedogenesis (Juvenile multiplication) refers to multiplication of juvenile/immature stages of parasite in intermediate hostS. E.g. Multiplication of immature stages of trematodes in snail

 

• Metagenesis (Alternation of generation) refers to sexual multiplication alternating with asexual multiplication, E.g. Trematodes, Sexual multiplication in definitive host alternating with paedogenesis in intermediate hosts

• Schizogony is a type of asexual division/multiplication in protozoa where a parasite multiplies into numerous individuals by multiple fission. The nucleus of the parasites undergoes repeated division without cytokinesis. e.g. apicomplexan parasites

 Click here to view an animation

• Gametogony is the differentiation of gamonts in to male and female gametes

• Syngamy is the union of the male and female gametes to form the zygote e.g. apicomplexan parasites

• Sporogony is the differentiation of zygote to oocyst, sporocyst and sporozoites e.g. all apicomplexan parasites.

 Click here to view an animation