Helminths cause great economic loss in livestock in Africa, and can be categorized as either direct or indirect losses. Arid and semi-arid lands (ASAL) in Kenya comprise 71 % of total land area and harbour the largest population of cattle, sheep and goats. However, little information on the distribution and impact of gastro-intestinal (GIT) parasitism in these animals is available. This survey was conducted to establish the prevalence of GIT parasites infecting calves, sheep and goats and their relative importance in Magadi division, which is semi-arid. Faecal samples were obtained directly from the rectum of 109 calves, 133 goats and 20 sheep and submitted to the laboratory for faecal worm egg counts, and coccidial oocysts examination using a modified McMaster method. The significance of differences in mean egg count per gram (epg) between animal species and herds (farms) were assessed using analysis of variance. The overall prevalence of nematodes in the calves, sheep and goats was 69.2 %, 80 % and 82 %, respectively. About 10 % of sheep and goats had epgs higher than 1 000, the remainder having light to moderate infections. The overall prevalence of coccidial oocysts in calves, sheep and goats was 30 %, 44 % and 45 %, respectively. Poor productivity in ASAL areas, where nutrition is often poor, is likely to be pronounced in the presence of parasite infections. These findings indicate that viable internal parasite control should be implemented in the study area in order to increase the productivity of the livestock there.

Helminths cause great economic loss in livestock in Africa, and can be categorized as either direct or indirect losses. Arid and semi-arid lands (ASAL) in Kenya comprise 71 % of total land area and harbour the largest population of cattle, sheep and goats. However, little information on the distribution and impact of gastro-intestinal (GIT) parasitism in these animals is available. This survey was conducted to establish the prevalence of GIT parasites infecting calves, sheep and goats and their relative importance in Magadi division, which is semi-arid. Faecal samples were obtained directly from the rectum of 109 calves, 133 goats and 20 sheep and submitted to the laboratory for faecal worm egg counts, and coccidial oocysts examination using a modified McMaster method. The significance of differences in mean egg count per gram (epg) between animal species and herds (farms) were assessed using analysis of variance. The overall prevalence of nematodes in the calves, sheep and goats was 69.2 %, 80 % and 82 %, respectively. About 10 % of sheep and goats had epgs higher than 1 000, the remainder having light to moderate infections. The overall prevalence of coccidial oocysts in calves, sheep and goats was 30 %, 44 % and 45 %, respectively. Poor productivity in ASAL areas, where nutrition is often poor, is likely to be pronounced in the presence of parasite infections. These findings indicate that viable internal parasite control should be implemented in the study area in order to increase the productivity of the livestock there.

Psittacine beak and feather disease (PBFD) is a common disease of the psittacine species and is caused by the psittacine beak and feather disease virus (PBFDV). In this study the occurrence of the disease in ring-neck parakeets and budgerigars in South Africa suffering from feathering problems, using polymerase chain reaction as a diagnostic test was investigated. The genetic variation between viral isolates was also studied. Results indicate that PBFDV can be attributed to being the cause of feathering problems in some of the ring-neck parakeets and budgerigars in South Africa. Genetic variation of isolates occurs between species and individuals. A cheap and easy to use method of blood sample collection on filter paper for diagnostic purposes was also evaluated. It proved to be less stressful to the birds and did not inhibit further processes.

Psittacine beak and feather disease (PBFD) is a common disease of the psittacine species and is caused by the psittacine beak and feather disease virus (PBFDV). In this study the occurrence of the disease in ring-neck parakeets and budgerigars in South Africa suffering from feathering problems, using polymerase chain reaction as a diagnostic test was investigated. The genetic variation between viral isolates was also studied. Results indicate that PBFDV can be attributed to being the cause of feathering problems in some of the ring-neck parakeets and budgerigars in South Africa. Genetic variation of isolates occurs between species and individuals. A cheap and easy to use method of blood sample collection on filter paper for diagnostic purposes was also evaluated. It proved to be less stressful to the birds and did not inhibit further processes.

Clarias gariepinus were collected from Lake Chivero, Zimbabwe, and examined for nematode parasites from November 2000 to May 2002. Of the 202 specimens collected, 42.6 % were infected with third-stage larvae of Contracaecum sp. in the body cavity. The intensity of the infection was 1-7 worms per fish (mean intensity = 2.2). Seasonal variation in the prevalence of the parasite was not obvious and there was no significant difference in the prevalence of infection between males and females (c2 = 2.228; P > 0.05). No significant relationship between host size and prevalence was established. There was also no significant relationship between intensity and the body condition factor (r = 0.11; P > 0.05). The low parasite prevalence may have been caused by the disruption of the infection cycle since piscivorous birds, which are the final hosts of the parasite, do not feed on C. gariepinus in Lake Chivero.

Clarias gariepinus were collected from Lake Chivero, Zimbabwe, and examined for nematode parasites from November 2000 to May 2002. Of the 202 specimens collected, 42.6 % were infected with third-stage larvae of Contracaecum sp. in the body cavity. The intensity of the infection was 1-7 worms per fish (mean intensity = 2.2). Seasonal variation in the prevalence of the parasite was not obvious and there was no significant difference in the prevalence of infection between males and females (c2 = 2.228; P 0.05). No significant relationship between host size and prevalence was established. There was also no significant relationship between intensity and the body condition factor (r = 0.11; P 0.05). The low parasite prevalence may have been caused by the disruption of the infection cycle since piscivorous birds, which are the final hosts of the parasite, do not feed on C. gariepinus in Lake Chivero.

Striped mice, Rhabdomys pumilio, were trapped over a period of 17 months in the Thomas Baines Nature Reserve, and placed in cages, over water, until all the ticks they harboured had detached. The mice were then returned to the reserve. Four ixodid tick species were recovered from the mice of which the larvae and nymphs of Rhipicephalus follis and Rhipicephalus simus were the most numerous. Most larvae of R. follis detached from mice trapped from March to July, and most nymphs in March and from June to September. Most larvae of R. simus detached from mice trapped from December to March, and most nymphs from January to March and during May and June. Seven ixodid tick species were collected from striped mice, house rats, Rattus rattus, vlei rats, Otomys spp. and Praomys sp. captured in the vicinity of human dwellings or animal holding facilities in the Grahamstown district. The striped mice captured in the Thomas Baines Reserve harboured considerably larger numbers of ticks than any of the rodent species in the more urbanized localit

Striped mice, Rhabdomys pumilio, were trapped over a period of 17 months in the Thomas Baines Nature Reserve, and placed in cages, over water, until all the ticks they harboured had detached. The mice were then returned to the reserve. Four ixodid tick species were recovered from the mice of which the larvae and nymphs of Rhipicephalus follis and Rhipicephalus simus were the most numerous. Most larvae of R. follis detached from mice trapped from March to July, and most nymphs in March and from June to September. Most larvae of R. simus detached from mice trapped from December to March, and most nymphs from January to March and during May and June. Seven ixodid tick species were collected from striped mice, house rats, Rattus rattus, vlei rats, Otomys spp. and Praomys sp. captured in the vicinity of human dwellings or animal holding facilities in the Grahamstown district. The striped mice captured in the Thomas Baines Reserve harboured considerably larger numbers of ticks than any of the rodent species in the more urbanized localit

One third of the manufacturer's prescribed dose of diminazene has long been used to block treat the South African unfrozen Babesia bigemina and Babesia bovis (redwater) vaccine reactions, with no known adverse effects. It is known that the inhibitory effect of antibabesial drugs is more pronounced in animals inoculated with the frozen vaccine than those with the unfrozen vaccine. Reports of vaccine failures in some animals in which diminazene was used for block treatment of the reactions following inoculation with frozen South African redwater vaccine led us to reinvestigate the required waiting period before treatment and the reduced dose necessary for successful treatment and development of immunity. Results from febrile reactions in cattle following vaccination indicated day 7 as the optimal day for administering block treatment. Treatment of B. bigemina vaccine reactions in cattle on day 7 at a level of 0.35 mg/kg (1/10 fraction of the normal dose) diminazene killed all the parasites while B. bovis vaccine parasites survived treatment using diminazene at levels between 0.35 mg/kg and 1.16 mg/kg. However, various other factors, such as the degree of natural resistance of different cattle breeds and individual animals, the accuracy of diminazene content according to the manufacturer's label claim and the accuracy of the drug dose administered, all influence the successful immunization of animals. Consequently block treating of Babesia vaccines with diminazene on day 7 after vaccination is not recommended.

One third of the manufacturer's prescribed dose of diminazene has long been used to block treat the South African unfrozen Babesia bigemina and Babesia bovis (redwater) vaccine reactions, with no known adverse effects. It is known that the inhibitory effect of antibabesial drugs is more pronounced in animals inoculated with the frozen vaccine than those with the unfrozen vaccine. Reports of vaccine failures in some animals in which diminazene was used for block treatment of the reactions following inoculation with frozen South African redwater vaccine led us to reinvestigate the required waiting period before treatment and the reduced dose necessary for successful treatment and development of immunity. Results from febrile reactions in cattle following vaccination indicated day 7 as the optimal day for administering block treatment. Treatment of B. bigemina vaccine reactions in cattle on day 7 at a level of 0.35 mg/kg (1/10 fraction of the normal dose) diminazene killed all the parasites while B. bovis vaccine parasites survived treatment using diminazene at levels between 0.35 mg/kg and 1.16 mg/kg. However, various other factors, such as the degree of natural resistance of different cattle breeds and individual animals, the accuracy of diminazene content according to the manufacturer's label claim and the accuracy of the drug dose administered, all influence the successful immunization of animals. Consequently block treating of Babesia vaccines with diminazene on day 7 after vaccination is not recommended.

The objective of this study was to establish a repeatable, standardized laboratory procedure for monitoring the development of antimicrobial resistance in bacteria isolated from animals and food of animal origin in South Africa, with reagents prepared in-house. The emergence of resistance and the spread of resistant bacteria can be limited by implementing a veterinary antimicrobial drug policy, in which inter alia systematic monitoring and prudent use play essential roles. The bacteria included in this study represented three different categories, namely zoonotic bacteria (Salmonella), indicator bacteria (Escherichia coli, Enterococcus faecalis and Enterococcus faecium) and veterinary pathogens (Mannheimia haemolytica). Thirty isolates of each species were collected with the aim of standardizing the laboratory methodology for a future national veterinary surveillance and monitoring programme. Susceptibility to ten selected antimicrobial drugs was determined by means of minimum inhibitory concentrations (MICs) using the microdilution method. The method according to the National Committee for Clinical Laboratory Standards was used as the standard. Multi-well plates containing varying dilutions of antimicrobial drugs and prepared in-house for MIC determinations, yielded repeatable results. Storage of plates for 2 months at -70 oC did not influence results meaningfully. Within this limited sample of bacteria, MIC results did not indicate meaningful resistance against any of the ten selected antimicrobial drugs. The findings of the study will be used to establish a national veterinary antimicrobial resistance surveillance and monitoring programme in South Africa. To allow for international comparison of data, harmonisation of the surveillance and monitoring programme in accordance with global trends is encouraged. Ideally it should be combined with a programme monitoring the quantities of antimicrobial drugs used. The aim is to contribute to slowing down the emergence of resistance and the problems associated with this phenomenon by means of the rational use of antimicrobial drugs.

The objective of this study was to establish a repeatable, standardized laboratory procedure for monitoring the development of antimicrobial resistance in bacteria isolated from animals and food of animal origin in South Africa, with reagents prepared in-house. The emergence of resistance and the spread of resistant bacteria can be limited by implementing a veterinary antimicrobial drug policy, in which inter alia systematic monitoring and prudent use play essential roles. The bacteria included in this study represented three different categories, namely zoonotic bacteria (Salmonella), indicator bacteria (Escherichia coli, Enterococcus faecalis and Enterococcus faecium) and veterinary pathogens (Mannheimia haemolytica). Thirty isolates of each species were collected with the aim of standardizing the laboratory methodology for a future national veterinary surveillance and monitoring programme. Susceptibility to ten selected antimicrobial drugs was determined by means of minimum inhibitory concentrations (MICs) using the microdilution method. The method according to the National Committee for Clinical Laboratory Standards was used as the standard. Multi-well plates containing varying dilutions of antimicrobial drugs and prepared in-house for MIC determinations, yielded repeatable results. Storage of plates for 2 months at -70 oC did not influence results meaningfully. Within this limited sample of bacteria, MIC results did not indicate meaningful resistance against any of the ten selected antimicrobial drugs. The findings of the study will be used to establish a national veterinary antimicrobial resistance surveillance and monitoring programme in South Africa. To allow for international comparison of data, harmonisation of the surveillance and monitoring programme in accordance with global trends is encouraged. Ideally it should be combined with a programme monitoring the quantities of antimicrobial drugs used. The aim is to contribute to slowing down the emergence of resistance and the problems associated with this phenomenon by means of the rational use of antimicrobial drugs.

A population-based study was carried out on the Ankole ranching scheme in south-west Uganda with the aim of determining the endemic status of Theileria parva infections. For this purpose, the age-related sero-prevalence of T. parva and the specific calf mortality associated with the parasite were assessed. Blood samples were collected from 931 Ankole calves of up to 12 months of age from 81 randomly selected herds. The relationship between rainfall pattern and whole-body Rhipicephalus appendiculatus counts was determined. The influence of tick control practices on East Coast fever-related calf mortality, and sero-positivity were also determined. A significant (r2 = 0.76, P = 0.000) association between R. appendiculatus counts and rainfall was observed. There was no significant (P > 0.05) association between theileriosis- related calf mortality, sero-positivity and the different tick control practices. Antibody prevalence based on the PIM ELISA was above 70 % among calves of 6 months of age in 96 % in all the herds. Theileria parva-related calf mortality determined by repeated herd visits and farm records ranged between 0% and 5.4 %. It was concluded that endemic stability for theileriosis, caused by T. parva, existed in the study area, and that the risk of the occurrence of economically important outbreaks of East Coast fever in indigenous cattle was regarded as minimal under the prevailing conditions.

A population-based study was carried out on the Ankole ranching scheme in south-west Uganda with the aim of determining the endemic status of Theileria parva infections. For this purpose, the age-related sero-prevalence of T. parva and the specific calf mortality associated with the parasite were assessed. Blood samples were collected from 931 Ankole calves of up to 12 months of age from 81 randomly selected herds. The relationship between rainfall pattern and whole-body Rhipicephalus appendiculatus counts was determined. The influence of tick control practices on East Coast fever-related calf mortality, and sero-positivity were also determined. A significant (r2 = 0.76, P = 0.000) association between R. appendiculatus counts and rainfall was observed. There was no significant (P 0.05) association between theileriosis- related calf mortality, sero-positivity and the different tick control practices. Antibody prevalence based on the PIM ELISA was above 70 % among calves of 6 months of age in 96 % in all the herds. Theileria parva-related calf mortality determined by repeated herd visits and farm records ranged between 0% and 5.4 %. It was concluded that endemic stability for theileriosis, caused by T. parva, existed in the study area, and that the risk of the occurrence of economically important outbreaks of East Coast fever in indigenous cattle was regarded as minimal under the prevailing conditions.