It is a parasite of the young as it stimulates an early immune response that protects adults against disease. Parasitic bronchitis is a disease of livestock management. Disease results when susceptible calves, such as dairy, stocker calves or cattle from areas which do not normally have Dictyocaulus , i.e., arid western ranges, are grazed in lush spring or autumn contaminated pastures. Conditions in pastures suitable for the propagation of mushrooms are similarly suitable for the transmission of Dictyocaulus . A dung-inhabiting fungus, Pilobolus, disseminates Dictyocaulus by propelling larvae through the air which have crawled onto sporangiophores.
Most modern anthelmintics are effective in controlling lungworms in cattle.
Calves treated after being infected exhibit resistance to infection. Liver flukes, Fasciola hepatica and Fascioloides magna , may be of major significance in some parts of the country. These parasites are restricted in their transmission by the presence of lymnaeidae snails. Flukes are also transmitted during the cool season in the south. The habitat suitable for these snails is variable, with soil and weather conditions determining whether or not transmission will occur in a given year.