Basic regulatory parameters of the host-parasite system for warble flies of farm animals using Hypoderma bovis as an example.

While studying the consistent patterns in the host-parasite relationships on the model of warble flies infesting cattle, a firm internal regulatory system governing the number of parasites on the host and reflected in the level of populations, has been demonstrated. This regulatory system is governed by mathematical-statistical laws and therefore can be modelled and its different features expressed mathematically. The distribution of parasites in the host population agrees with the negative binomial distribution. Main mathematical formulations of the regulatory system (parameters) and defensive responses of the host to the invasion of parasites are analyzed. From the above consistent patterns important conclusions are drawn for the control of cattle hypodermatosis in practice. The mathematical model elucidates two states of control--the first stage conforms to the natural regulatory system leading to a marked decrease of the degree of infestation, and the second stage is aiming at the eradication of the disease. It may be deduced from the above said that the control of hypodermatosis is expedient primarily in juvenile cattle, as shown by the results of the control carried out in Czechoslovakia.