Dr. Kassai Tibor szerk.: Parasitologia Hungarica 1. (Budapest, 1968)

appetite, are sleepy, lag behind the rest and have diarrhoea, the yellowish pasty droppings of sick turkeys beiny immediately noticed. In such circumstances blackhead is easily diagnosed by postmortem examination of the most ailing birds Delayed treatment for blackhead Is often due to erroneous diagnosis. Considerable distention of the ceaca of affected birds and caseous-fibrinous plugs in the caecal lumina superficially resemble lesions encountered in the caecal coccidiosis of chickens. In fact, like most domesticated animals, the turkey has several coccidian parasites. Yet oocysts are always demonstrable in the droppings, often even in the pasty stool seen during the early phase of blackhead. Although the presence of oocysts apparently supports the diagnosis of caecal coccidiosis no turkey coccidium is known to cause such extensive caecal lesions. Good durable therapeutic results can be obtained if 1 $> Hepamix is given in the diet for 7-10 days. Subsequently treatment must not be stopped but continued at half the dose rate for at least as long a time. As indicated in the literature, the disease is liable to recur even then, indicating that the immune response to blackhead is very low (for ref.see BIESTER and SCHWARTE,

1965). 4.) Prophylaxis of blackhead. In the spread of blackhead the most important role has been attributed to the eggs of Heterakis gallinarum

. The etiological agents of blackhead are carried either by these eggs, or by the larvae hatched from them, through the wall of the caecum and invade the host. Therefore, turkeys should be housed and managed so that they remain free of infection with Heterakis eggs. In this respect, Heterakis eggs shed with chicken droppings seem to be even more dangerous than those excreted by the turkeys themselves. It is known that blackhead also occurs in gallinaceous birds,but affects them only slightly or net at all» Nevertheless

,the Heterakis eggs shed with the droppings of gallinaceous birds may infect relatively large areas for long periods of time. The first and most important rule of blackhead prophylaxis is to prevent all contact of the turkeys with Heterakis ova. These pa-