World association for the advancement of veterinary parasitology (WAAVP): second edition of guidelines for evaluating the efficacy of equine anthelmintics.

These guidelines have been designed to assist in the planning, operation and interpretation of studies which would serve to assess the efficacy of drugs against internal parasites of horses. Although the term anthelmintic is used in the title and text, these guidelines include studies on drug efficacy against larvae of horse bot flies, Gasterophilus spp., which are non-helminth parasites commonly occurring in the stomach of horses. The advantages, disadvantages and application of critical and controlled tests are presented. Information is also provided on selection of animals, housing, feed, dose titration, confirmatory and clinical trials, record keeping and necropsy procedures. These guidelines should assist both investigators and registration authorities in the evaluation of compounds using comparable and standard procedures with the minimum number of animals.

World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) guidelines for evaluating the efficacy of equine anthelmintics.

These guidelines have been designed to assist in the planning, operation and interpretation of studies which would serve to assess the efficacy of drugs against internal parasites of horses. Although the term anthelmintic is used in the title and text, these guidelines include studies on drug efficacy against larvae of horse bot flies, Gasterophilus spp, which are non-helminth parasites commonly occurring in the stomach of horses. The advantages, disadvantages and application of critical and controlled tests are presented. Information is also provided on selection of animals, housing, feed, dose titration, confirmatory and clinical trials, record keeping and necropsy procedures. These guidelines should assist both investigators and registration authorities in the evaluation of compounds using comparable and standard procedures with the minimum number of animals.

Oslerus (Filaroides) osleri in a dog.

A young female Queensland Blue Heeler with signs of severe respiratory distress was diagnosed as having Oslerus osleri. Radiographic, bronchoscopic, parasitologic and pathologic findings are described and treatment is briefly reviewed. A possible route of larval migration from the pulmonary capillaries to the predilection site is proposed.

Hydatid disease in the Turkana District of Kenya, IV. The prevalence of Echinococcus granulosus infections in dogs, and observations on the role of the dog in the lifestyle of the Turkana.

The prevalence of Echinococcus granulosus in dogs in the Turkana District of Kenya was 39.4% of 695 examined. Of these, 98 (35.8%) had heavy Echinococcus worm burdens (10(3)-5 X 10(4) ), while 54 (19.7%) and 122 (44.5%) had medium (201-1000) and light (1-200) burdens. The possible sources of these infections are discussed. The prevalence rate differed in various parts of the district, ranging from 63.5% in the northwest, where the highest incidence of human hydatidosis also occurs, to nil along the shores of Lake Turkana. Infection rates of 32.0% and 16.7% were recorded at Lokitaung (north-east) and Lodwar (central), while in the south 48.9% of dogs harboured Echinococcus. This latter figure is surprising as the area has a low incidence of human hydatidosis. The Turkana keep a large number of dogs, and the reasons for this and the social role of the dog in the district is discussed. No difference in susceptibility was found between Turkana-type dogs and those of mixed breeds from Nairobi when they were experimentally infected with hydatid protoscolices from man, camels, cattle, sheep and goats. However, it proved difficult to infect the Turkana-type of dogs with viable protoscolices of cattle origin. The reasons for this and its epidemiological implications remain unclear. It is suggested that droughts, which affect Turkana every six to ten years, may play an important role in the perpetuation of hydatid disease in the area.

Hydatid disease in the Turkana District of Kenya. III. The significance of wild animals in the transmission of Echinococcus granulosus, with particular reference to Turkana and Masailand in Kenya.

The results are given of a study on the role of wildlife in the transmission of Echinococcus granulosus in the Turkana and Narok Districts of Kenya. A total of 76 wild carnivores belonging to three separate species was examined from Turkana District. Echinococcus adults were found in 11 of 38 silver-backed jackals (Canis mesomelas) and in six of 22 golden jackals (Canis aureus). This is the first record of golden jackals being infected with this parasite in Kenya. None of 16 spotted hyaenas (Crocuta crocuta) harboured the parasite. Morphological features of the parasites obtained from the jackals were compared with material obtained from dogs in the same area. No morphological differences were recorded when this material was compared with data reported by others, hence the Turkana material belonged to the single species E. granulosus. Three silver-backed jackals and three puppies (Canis familiaris) were successfully infected with protoscolices obtained from a hydatid cyst surgically removed from a Turkana patient. Three spotted hyaenas fed the same material failed to become infected. None of 152 wild herbivores of five species examined in Turkana harboured hydatid cysts. The natural jackal infections in this District are thought to be incidental and dependent on the continuance of the domestic cycle. The role of the Turkana themselves in the perpetuation of the cycle is discussed. Twenty-six wild herbivores of six species were examined for hydatid cysts, in Narok District; hydatids were found in three wildebeest (Connochaetes taurinus) and a single topi (Damaliscus korrigum). The discovery of fertile cysts in wildebeest and the reported infections in lions (Panthera leo), Cape hunting dogs (Lycaon pictus) and silver-backed jackals, support previous evidence of the existence of a wildlife cycle in the Masailand and Serengeti regions of East Africa. The relationship of this cycle to the domestic cycle operating in the same area is unclear and requires further investigation.

A preliminary field trial to evaluate the use of immunisation for the control of naturally acquired Taenia saginata infection in cattle.

The efficiency of immunisation of cattle with antigens collected during 14-day in vitro cultivation of Taenia saginata or T hydatigena oncospheres for the control of naturally acquired bovine cysticercosis was tested on a farm which uses sewage effluent to irrigate pasture. A total of 260 first-calf heifers of mixed breed were divided into four groups which were either sham-vaccinated or vaccinated with T saginata antigen at 49 to 124 days or 16 to 91 days before calving or vaccinated at 49 to 124 days prepartum with T hydatigena antigen. Ten calves from each group were killed at about three months of age and all muscles, including heart, tongue and oesophagus, were examined for cysticerci. Precalving vaccination with T saginata antigen significantly reduced the number of cysticerci found. Calves from sham-vaccinated cows were either sham-vaccinated or vaccinated with T saginata antigen or T hydatigena antigen at 46 to 121 days olds. Calves from cows immunised with T saginata antigen were either sham-vaccinated or immunised with T saginata antigen. Calves from cows injected with T hydatigena antigen were either sham-vaccinated, vaccinated once with T hydatigena antigen when 46 to 121 days of age or vaccinated twice with T hydatigena antigen at median ages of 65 days and 99 days. All these calves were killed at 13 to 14 months old and their heart, diaphragm, tongue and masticatory muscles examined for cysticerci. Of the 38 surviving sham-vaccinated calves from sham-vaccinated cows, 21 animals (55 per cent) were infected. Several of the vaccination regimes reduced this rate of infection significantly but the most effective was precalving vaccination of the cow and vaccination of the calf with T saginata antigen which reduced infection by 78 per cent compared with the controls. Precalving vaccination of cows with T hydatigena antigen together with double vaccination of their calves with the same antigen preparation also significantly reduced infection in the calves by 64 per cent.

Preliminary observations on the removal of Taenia saginata eggs from sewage using various treatment processes.

Cattle were grazed for four months on pasture irrigated by effluent from activated sludge plants, a trickling filter plant, from a lagooning process with raw sewage, and then killed and their heart, diaphragm, tongue, and muscles of their head and one forelimb were sliced and examined for Cysticercus bovis. None of the cattle grazed on pasture irrigated with effluent from lagooning were infected compared with 3.3% from the trickling filter plant, 9.0% and 12.5% from the two activated sludge plants and 30.0% of cattle on pastures irrigated with raw sewage. Of the 40 control calves killed at the time the test calves were placed on the various pastures, 2.5% were infected. It appears that modern sewage purification methods do not efficiently remove Taenia saginata from the final effluent and that prolonged settling is necessary before effluent is used to irrigate cattle pastures if C. bovis infection is to be reduced to very low levels.