A total of 17 commercially reared ostriches (Struthio camelus) from Msengi farm, Chinhoyi, Zimbabwe, observed with swollen eyes, severe conjunctivitis and constant lacrimation accompanied by a purulent exudate, were restrained for further clinical examination. Some of the birds were semi-blind with severe loss of body condition. When examined, tiny organisms were observed attached to the nictitating membranes and the conjuctival sacs of both eyes. The organisms were identified as Philophthalmus gralli, the "oriental eye-fluke" and Melanoides tuberculata, a prosobranch snail, was confirmed as the intermediate host through natural and experimental infection. To the best of our knowledge this is the first record of the oriental eye-fluke infection in birds in Zimbabwe and Africa and extends its known geographical range.

A total of 17 commercially reared ostriches (Struthio camelus) from Msengi farm, Chinhoyi, Zimbabwe, observed with swollen eyes, severe conjunctivitis and constant lacrimation accompanied by a purulent exudate, were restrained for further clinical examination. Some of the birds were semi-blind with severe loss of body condition. When examined, tiny organisms were observed attached to the nictitating membranes and the conjuctival sacs of both eyes. The organisms were identified as Philophthalmus gralli, the "oriental eye-fluke" and Melanoides tuberculata, a prosobranch snail, was confirmed as the intermediate host through natural and experimental infection. To the best of our knowledge this is the first record of the oriental eye-fluke infection in birds in Zimbabwe and Africa and extends its known geographical range.

Three hundred and eighty-four samples of leaf litter, soil, faeces from domestic and game animals, compost and aqueous cultures of infective nematode larvae contaminated with unidentified fungi were plated out on water agar, baited with pure infective larvae of Haemonchus contortus, incubated and examined for the presence of nematophagous fungi. Duddingtonia flagrans was isolated from five samples, and 73 samples were positive for other nematophagous fungi.

Three hundred and eighty-four samples of leaf litter, soil, faeces from domestic and game animals, compost and aqueous cultures of infective nematode larvae contaminated with unidentified fungi were plated out on water agar, baited with pure infective larvae of Haemonchus contortus, incubated and examined for the presence of nematophagous fungi. Duddingtonia flagrans was isolated from five samples, and 73 samples were positive for other nematophagous fungi.

Two hundred and seventy-three elephant shrews, consisting of 193 Elephantulus myurus, 67 Elephantulus edwardii and 13 animals belonging to other species, were examined for ixodid ticks at 18 localities in South Africa and Namibia. The immature stages of Ixodes rubicundus, Rhipicentor nuttalli, Rhipicephalus warburtoni and a Rhipicephalus pravus-like tick were the most numerous of the 18 tick species recovered. Substantial numbers of immature Rhipicephalus arnoldi, Rhipicephalus distinctus and Rhipicephalus exophthalmos were also collected from elephant shrews at particular localities. Larvae of I. rubicundus were most numerous on E. myurus in Free State Province from April to July and nymphs from June to October. Larvae of R. nuttalli were most numerous on these animals during April, May, August and September, and nymphs in February and from April to August. The immature stages of R. warburton were collected from E. myurus only in Free State Province, and larvae were generally most numerous from December to August and nymphs from April to October.

Two hundred and seventy-three elephant shrews, consisting of 193 Elephantulus myurus, 67 Elephantulus edwardii and 13 animals belonging to other species, were examined for ixodid ticks at 18 localities in South Africa and Namibia. The immature stages of Ixodes rubicundus, Rhipicentor nuttalli, Rhipicephalus warburtoni and a Rhipicephalus pravus-like tick were the most numerous of the 18 tick species recovered. Substantial numbers of immature Rhipicephalus arnoldi, Rhipicephalus distinctus and Rhipicephalus exophthalmos were also collected from elephant shrews at particular localities. Larvae of I. rubicundus were most numerous on E. myurus in Free State Province from April to July and nymphs from June to October. Larvae of R. nuttalli were most numerous on these animals during April, May, August and September, and nymphs in February and from April to August. The immature stages of R. warburton were collected from E. myurus only in Free State Province, and larvae were generally most numerous from December to August and nymphs from April to October.

During the period between January 1999 and December 2000, the distribution and seasonal patterns of amphistome infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe were determined through monthly coprological examination. Cattle faecal samples were collected from 12 and nine dipping sites in the highveld and lowveld communal grazing areas, respectively. Patterns of distribution and seasonal fluctuations of intermediate host-snail populations and the climatic factors influencing the distribution were also determined by sampling at monthly intervals for a period of 24 months (November 1998 to October 2000) in six dams and six streams in the highveld and in nine dams in the lowveld communal grazing areas. Each site was sampled for relative snail density and the vegetation cover and type, physical and chemical properties of water, and mean monthly rainfall and temperature were recorded. Aquatic vegetation and grass samples 0-1 m from the edges of the snail habitats were collected monthly to determine the presence or absence of amphistome metacercariae. Snails collected at the same time were individually checked for the emergence of larval stages of amphistomes. A total of 16 264 (calves 5 418, weaners 5 461 and adults 5 385) faecal samples were collected during the entire period of the study and 4 790 (29.5 %) of the samples were positive for amphistome eggs. For both regions the number of animals positive for amphistome eggs differed significantly between the 2 years, with the second year having a significantly higher prevalence (P < 0.01) than the first year. Significantly higher prevalences were found in the highveld compared to the lowveld (P < 0.001), for adult cattle than calves (P < 0.01), and in the wet over the dry season (P < 0.01). Faecal egg output peaked from October to March in both years of the study. Bulinus tropicus, Bulinus forskalii and Biomphalaria pfeifferi were recorded from the study sites. The main intermediate host for amphistomes was B. tropicus with a prevalence of infection of 8.5 %. However, amphistome cercariae were also recorded in Biom. Pfeifferi and B. forskalii. Amphistome cercariae were recorded from both the highveld and lowveld areas with peak prevalence during the post-rainy season (March to May). Metacercariae were found on herbage from the fringes of the snail habitats between February and August, with most of the metacercariae concentrated on herbage 0-1 m from the edges of the habitats. Based on the epidemiological findings a control programme was devised. From this study, large burdens of immature flukes could be expected in cattle during the dry months. Since adult cattle would be resistant to the pathogenic effects of the migrating immature amphistomes the target for control would be young animals being exposed to the infection for the first time. Therefore, the first anthelmintic treatment can be administered in calves in mid June when maximum migration of immature amphistomes starting 3-4 weeks after infection in the early dry season would be expected. A second treatment could be given in late July or early August to remove potentially dangerous burdens of immature flukes acquired later in the dry season. Where resources permit, another strategy would be to treat against the mature flukes in March or April in order to reduce the number of eggs deposited on pastures and the opportunity for infection of the intermediate host snails. To reduce cercarial shedding by the intermediate host snails molluscicides can also be applied during the peak transmission periods (April/May and August/September).

During the period between January 1999 and December 2000, the distribution and seasonal patterns of amphistome infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe were determined through monthly coprological examination. Cattle faecal samples were collected from 12 and nine dipping sites in the highveld and lowveld communal grazing areas, respectively. Patterns of distribution and seasonal fluctuations of intermediate host-snail populations and the climatic factors influencing the distribution were also determined by sampling at monthly intervals for a period of 24 months (November 1998 to October 2000) in six dams and six streams in the highveld and in nine dams in the lowveld communal grazing areas. Each site was sampled for relative snail density and the vegetation cover and type, physical and chemical properties of water, and mean monthly rainfall and temperature were recorded. Aquatic vegetation and grass samples 0-1 m from the edges of the snail habitats were collected monthly to determine the presence or absence of amphistome metacercariae. Snails collected at the same time were individually checked for the emergence of larval stages of amphistomes. A total of 16 264 (calves 5 418, weaners 5 461 and adults 5 385) faecal samples were collected during the entire period of the study and 4 790 (29.5 %) of the samples were positive for amphistome eggs. For both regions the number of animals positive for amphistome eggs differed significantly between the 2 years, with the second year having a significantly higher prevalence (P 0.01) than the first year. Significantly higher prevalences were found in the highveld compared to the lowveld (P 0.001), for adult cattle than calves (P 0.01), and in the wet over the dry season (P 0.01). Faecal egg output peaked from October to March in both years of the study. Bulinus tropicus, Bulinus forskalii and Biomphalaria pfeifferi were recorded from the study sites. The main intermediate host for amphistomes was B. tropicus with a prevalence of infection of 8.5 %. However, amphistome cercariae were also recorded in Biom. Pfeifferi and B. forskalii. Amphistome cercariae were recorded from both the highveld and lowveld areas with peak prevalence during the post-rainy season (March to May). Metacercariae were found on herbage from the fringes of the snail habitats between February and August, with most of the metacercariae concentrated on herbage 0-1 m from the edges of the habitats. Based on the epidemiological findings a control programme was devised. From this study, large burdens of immature flukes could be expected in cattle during the dry months. Since adult cattle would be resistant to the pathogenic effects of the migrating immature amphistomes the target for control would be young animals being exposed to the infection for the first time. Therefore, the first anthelmintic treatment can be administered in calves in mid June when maximum migration of immature amphistomes starting 3-4 weeks after infection in the early dry season would be expected. A second treatment could be given in late July or early August to remove potentially dangerous burdens of immature flukes acquired later in the dry season. Where resources permit, another strategy would be to treat against the mature flukes in March or April in order to reduce the number of eggs deposited on pastures and the opportunity for infection of the intermediate host snails. To reduce cercarial shedding by the intermediate host snails molluscicides can also be applied during the peak transmission periods (April/May and August/September).

The objective was to develop a non-terminal, acute normovolaemic anaemia model in dogs that has minimal effects on patient well-being. Eleven normal Beagle dogs were used. About 20 % of the circulating blood volume was removed from the jugular vein 1-3 times per day over a 3-4 day period until a haematocrit (Ht) of 13-17 % was obtained. Normovolaemia was maintained by replacing the volume deficit of the red blood cells with Ringer's lactate and re-infusing the plasma. Full blood count and Ht were monitored twice daily. The 13-17 % Ht was reached within 3-4 days with the number of phlebotomies ranging from four to seven. The model was primarily developed to determine echocardiographic values as well as Doppler abdominal splanchnic blood flow parameters in anaemic dogs as part of a study that will compare these results to similar studies in babesiosis-induced anaemia. The model may also be useful in the evaluation of the pathophysiology of anaemia in dogs or as a model for anaemia in humans.

The objective was to develop a non-terminal, acute normovolaemic anaemia model in dogs that has minimal effects on patient well-being. Eleven normal Beagle dogs were used. About 20 % of the circulating blood volume was removed from the jugular vein 1-3 times per day over a 3-4 day period until a haematocrit (Ht) of 13-17 % was obtained. Normovolaemia was maintained by replacing the volume deficit of the red blood cells with Ringer's lactate and re-infusing the plasma. Full blood count and Ht were monitored twice daily. The 13-17 % Ht was reached within 3-4 days with the number of phlebotomies ranging from four to seven. The model was primarily developed to determine echocardiographic values as well as Doppler abdominal splanchnic blood flow parameters in anaemic dogs as part of a study that will compare these results to similar studies in babesiosis-induced anaemia. The model may also be useful in the evaluation of the pathophysiology of anaemia in dogs or as a model for anaemia in humans.

Dairy cattle reared in western Kenya are exposed to medium to high levels of trypanosomosis risk. The social background, farm characteristics and dairy cattle productivity of 90 and 30 randomly selected farmers from medium- and high-risk trypanosomosis areas, respectively, were compared. All the 120 farmers were visited between July and August 2002. Data analysis was performed using descriptive statistics and analysis of variance. The results showed that increased trypanosomosis risk represented by an increase in disease prevalence in cattle of 1% to 20 % decreased the density of dairy cattle by 53 % and increased the calving interval from 14 to 25 months. The increased risk was also associated with a significant increase in cattle mortalities and in a lactation period of 257 to 300 days. It was concluded that removal of the trypanosomosis constraint on dairy production would lead to expansion of dairying since the domestic demand for dairy products is expected to increase.

Dairy cattle reared in western Kenya are exposed to medium to high levels of trypanosomosis risk. The social background, farm characteristics and dairy cattle productivity of 90 and 30 randomly selected farmers from medium- and high-risk trypanosomosis areas, respectively, were compared. All the 120 farmers were visited between July and August 2002. Data analysis was performed using descriptive statistics and analysis of variance. The results showed that increased trypanosomosis risk represented by an increase in disease prevalence in cattle of 1% to 20 % decreased the density of dairy cattle by 53 % and increased the calving interval from 14 to 25 months. The increased risk was also associated with a significant increase in cattle mortalities and in a lactation period of 257 to 300 days. It was concluded that removal of the trypanosomosis constraint on dairy production would lead to expansion of dairying since the domestic demand for dairy products is expected to increase.