Establishment Studies of the life cycle of Raillietina cesticillus,Choanotaenia infundibulum and Hymenolepis carioca.

Abstract

Establishment of the life cycle of three cestodes Raillietina cesticillus, Choanotaenia infundibulum and Hymenolepis carioca was studied in three insects that act as intermediate hosts, namely Tribolium castaneum, Alphitobius diaperinus and Musca domestica and in white Leghorn chicks, the definitive host. Insects were experimentally infected with gravid segments of the three cestodes. White Leghorn chicks were reared in insect- proof cages and experimentally infected with cysticercoids previously established in adult T. castaneum and A. diaperinus. In a field study, 1205 different insects collected in Shambat and Elhalfaya in Khartuom North, were dissected to determine their natural infection with poultry cestodes. Raillietina cesticillus, C. infundibulum and H. carioca established in adult T. castaneum whereas C. infundibulum was the only tapeworm that established in adult and larvae of A. diaperinus. Nevertheless, R. cesticillus and C. infundibulum did not established in M. domestica larvae. R. cesticillus had the highest infectivity to T. castaneum compared to the other tapeworms. Raillietina cesticillus, C. infundibulum and H. carioca established in white Leghorn chicks. Age of the cysticercoid and type of intermediate host in addition to the procedure of administering the infection affected their establishment. Search for natural intermediate hosts for poultry cestodes in the field revealed the presence of four species of beetles carrying meta- cestode infection. Two of the beetles, Anthicus formicarius and A. diaperinus, were 17 found infected with C. infundibulum whereas the other two, Hypocalcculus praecox and Carcinops troglodytes, were found harbouring R. cesticillus cysticercoids. No metacestodal infection was found in adult T. castaneum or M. domestica larvae. This is the first record of A. formicarius, H. praecox and C. troglodytes as intermediate hosts for C. infundibulum and R. cesticillus in the Sudan. It is concluded that the present findings contribute to the understanding of the properties of some experimental models e.g. C. infundibulum in A. diaperinus, R. cesticillus in T. castaneum and H. carioca in T. castaneum that can be used in several fundamental investigations (chemotherapy, immunology etc.). Immune mechanism of the insect may be an essential factor that reduces the infectivity of C. infundibulum cysticercoids developed in A. diaperinus. The nature of this reaction requires further investigations. It is recommended that for the purpose of control of these cestodes it is essential to manage their potential intermediate host(s).