Observations are reported on the fluctuations in populations of gastro-intestinal nematode parasites in 68 calves on two dairy farms in Fiji based on fortnightly faecal worm egg counts over a 3-year period. On one of the farms the calves began to graze soon after birth; on the other farm they were reared indoors until they were weaned at 6 months of age.The important species were Cooperia spp., Bunostomum phlebotomum, Haemonchus placei, H. similis and Oesophagostomum radiatum. Only small numbers of Trichostrongylus spp., Mecistocirrus digitatus and Neoascaris vitulorum were present.Potentially pathogenic worm burdens were only found in young cattle, mostly between 2 and 15 months of age. Faecal egg counts for each parasite species rose independently to a peak and then declined to low levels. For most species there was a close relationship between the time at which the peak faecal egg count occurred and the age of calves on the same farm, irrespective of the season in which the calves began to graze. This is considered to be due to the high rainfall and constant high temperatures throughout the year resulting in at least minimal favourable conditions for the development and survival of the pre-parasitic stages of all species in all months of the year. It is concluded that the succession of species which occurred must be strongly influenced by intrinsic factors in the life-history of each parasite.Tere were differences in the levels of peak egg counts between groups of calves which began to graze in different seasons but almost all parasite species examined were affected equally. The lowest levels were recorded in calves which were first exposed continuously to infection at the beginning of the dry season and the highest levels in those exposed at the beginning of the wet season.Protection of calves from parasite infection, by indoor rearing until weaning at 6 months of age, did not confer any striking advantage as the acquisition of potentially pathogenic worm burdens was merely delayed.The results are discussed in the light of recent theoretical concepts regarding the immunological control of helminth parasite infection.I am indebted to Mr A. E. Harness of Wainivesi for permitting observations to be made on his dairy farm, to Deo Raj Singh and Ram Kumar for technical assistance, and to Dr D. F. Stewart and Dr J. K. Dineen of the McMaster Laboratory for their criticism of the manuscript. My thanks are due to Miss Suzanne Dodd and Mr I. T. Roper of the McMaster Laboratory for the preparation of the figures. The permission of the Director of Agriculture, Fiji, to publish this paper is gratefully acknowledged.
Gastrointestinal Parasite Infection on Stray Cat and Pet Cat at Blitar Regency, East Java Province
