Three each of 3-year-old Angus and Simmental heifers, surgically modified to collect bile, were used to measure the effects of pregnancy and breed on bile flow, biliary copper and zinc excretion and plasma copper and zinc concentrations. Bile copper excretion was significantly higher at 7-mo of pregnancy when samples from both breeds were pooled. From then onwards it declined to its lowest, one week post-partum. During pregnancy, plasma copper concentration increased slightly, reaching its highest level at 7-mo of pregnancy and then decreased slightly until full term. In pooled samples from both breeds, the correlation between increase in bile copper excretion and plasma copper concentration from 0 to 7-mo of pregnancy was high (r = 0.85) and significant (p 0.05). Plasma zinc concentration decreased to the lowest level around 6-mo of pregnancy but increased thereafter until full term. In cows that were dried off one week after parturition, major shifts in bile and plasma copper and zinc parameters occurred at one week following and these coincided with a marked decline of bile flow and bile copper and zinc excretion. By 3-mo post-partum, biliary copper and zinc excretion and plasma copper and zinc concentrations had reached levels observed prior to pregnancy. When the data from all samples were pooled, the bile flow and bile copper excretion were significantly (p 0.05) higher in Simmental, and plasma copper and zinc concentration higher in the Angus.

Three each of 3-year-old Angus and Simmental heifers, surgically modified to collect bile, were used to measure the effects of pregnancy and breed on bile flow, biliary copper and zinc excretion and plasma copper and zinc concentrations. Bile copper excretion was significantly higher at 7-mo of pregnancy when samples from both breeds were pooled. From then onwards it declined to its lowest, one week post-partum. During pregnancy, plasma copper concentration increased slightly, reaching its highest level at 7-mo of pregnancy and then decreased slightly until full term. In pooled samples from both breeds, the correlation between increase in bile copper excretion and plasma copper concentration from 0 to 7-mo of pregnancy was high (r = 0.85) and significant (p < 0.05). Plasma zinc concentration decreased to the lowest level around 6-mo of pregnancy but increased thereafter until full term. In cows that were dried off one week after parturition, major shifts in bile and plasma copper and zinc parameters occurred at one week following and these coincided with a marked decline of bile flow and bile copper and zinc excretion. By 3-mo post-partum, biliary copper and zinc excretion and plasma copper and zinc concentrations had reached levels observed prior to pregnancy. When the data from all samples were pooled, the bile flow and bile copper excretion were significantly (p < 0.05) higher in Simmental, and plasma copper and zinc concentration higher in the Angus.

Three each of 3-year-old Angus and Simmental heifers, surgically modified to collect bile, were used to measure the effects of pregnancy and breed on bile flow, biliary copper and zinc excretion and plasma copper and zinc concentrations. Bile copper excretion was significantly higher at 7-mo of pregnancy when samples from both breeds were pooled. From then onwards it declined to its lowest, one week post-partum. During pregnancy, plasma copper concentration increased slightly, reaching its highest level at 7-mo of pregnancy and then decreased slightly until full term. In pooled samples from both breeds, the correlation between increase in bile copper excretion and plasma copper concentration from 0 to 7-mo of pregnancy was high (r = 0.85) and significant (p < 0.05). Plasma zinc concentration decreased to the lowest level around 6-mo of pregnancy but increased thereafter until full term. In cows that were dried off one week after parturition, major shifts in bile and plasma copper and zinc parameters occurred at one week following and these coincided with a marked decline of bile flow and bile copper and zinc excretion. By 3-mo post-partum, biliary copper and zinc excretion and plasma copper and zinc concentrations had reached levels observed prior to pregnancy. When the data from all samples were pooled, the bile flow and bile copper excretion were significantly (p < 0.05) higher in Simmental, and plasma copper and zinc concentration higher in the Angus.

The use of haematological techniques to assess fish health is generally accepted. The aim of the current study was to determine selected haematological changes that occur in Clarias gariepinus (Burchell, 1822). infected with trypanosomes. Blood films were prepared according to standard techniques to confirm trypanosome infections and whole blood was collected, the serum and plasma separated, and prepared for albumin and total protein concentration analysis. Plasma albumin levels were significantly higher in infected wild caught fish than in uninfected wild caught fish and uninfected breeding stock. Serum albumin levels were significantly lower in infected wild caught fish when compared to uninfected breeding stock. The total plasma and serum protein levels were within the normal range for C. gariepinus, that is, 3 g – 6 g/100 mL. The total plasma protein levels varied significantly between the three groups. However, the total serum protein levels were only significantly different between uninfected breeding stock and uninfected wild caught fish, as well as uninfected breeding stock and infected wild caught fish. The total protein levels were significantly higher in infected wild caught fish than in the other groups, a possible indication of an infection or inflammatory host response.

The use of haematological techniques to assess fish health is generally accepted. The aim of the current study was to determine selected haematological changes that occur in Clarias gariepinus (Burchell, 1822). infected with trypanosomes. Blood films were prepared according to standard techniques to confirm trypanosome infections and whole blood was collected, the serum and plasma separated, and prepared for albumin and total protein concentration analysis. Plasma albumin levels were significantly higher in infected wild caught fish than in uninfected wild caught fish and uninfected breeding stock. Serum albumin levels were significantly lower in infected wild caught fish when compared to uninfected breeding stock. The total plasma and serum protein levels were within the normal range for C. gariepinus, that is, 3 g – 6 g/100 mL. The total plasma protein levels varied significantly between the three groups. However, the total serum protein levels were only significantly different between uninfected breeding stock and uninfected wild caught fish, as well as uninfected breeding stock and infected wild caught fish. The total protein levels were significantly higher in infected wild caught fish than in the other groups, a possible indication of an infection or inflammatory host response.

In this review, the main gastrointestinal nematodes infecting cattle in Zimbabwe and the epidemiological factors influencing their occurrence are reviewed and discussed. Nineteen gastrointestinal nematode species that belong to seven families have been found to occur in cattle in Zimbabwe. The main genera reported to date are Cooperia, Haemonchus, Trichostrongylus and Oesophagostomumand the dominant species are Cooperia pectinata, Cooperia punctata, Haemonchus placei and Trichostrongylus axei. The mixed infection by several species from the genera is the cause of parasitic gastroenteritis in cattle in Zimbabwe. Production and husbandry practices, season, host age and environment are considered to be the main factors that influence gastrointestinal nematode infection in cattle. The geographical distribution of the gastrointestinal nematodes is also reviewed in relation to the climatic conditions of the country. Various control options are discussed and how they are applicable to the Zimbabwean situation. Based on reports and existing data on the epidemiological features of the gastrointestinal nematode infection in cattle, practical control measures are critically reviewed and recommendations are made for a national control programme.

In this review, the main gastrointestinal nematodes infecting cattle in Zimbabwe and the epidemiological factors influencing their occurrence are reviewed and discussed. Nineteen gastrointestinal nematode species that belong to seven families have been found to occur in cattle in Zimbabwe. The main genera reported to date are Cooperia, Haemonchus, Trichostrongylus and Oesophagostomumand the dominant species are Cooperia pectinata, Cooperia punctata, Haemonchus placei and Trichostrongylus axei. The mixed infection by several species from the genera is the cause of parasitic gastroenteritis in cattle in Zimbabwe. Production and husbandry practices, season, host age and environment are considered to be the main factors that influence gastrointestinal nematode infection in cattle. The geographical distribution of the gastrointestinal nematodes is also reviewed in relation to the climatic conditions of the country. Various control options are discussed and how they are applicable to the Zimbabwean situation. Based on reports and existing data on the epidemiological features of the gastrointestinal nematode infection in cattle, practical control measures are critically reviewed and recommendations are made for a national control programme.

In 2004, a new concept was introduced for simplifying identification of larvae of the common nematodes of cattle, sheep and goats that comprises estimates of the lengths of the sheath tail extensions of infective third-stage larvae (L3) of each genus and/or species to that of Trichostrongylus spp., instead of having to be dependent only on measurements in micrometre. For example, if the mean length of the sheath tail extension (the extension of the sheath caudad, beyond the caudal tip of the larva) of Trichostrongylus colubriformis and Trichostrongylus axei is assumed to be ‘X’, then that ofHaemonchus contortus is 2.0–2.7 ‘X’ – a difference that is not difficult to estimate. An additional new approach suggested now, particularly for L3 of species and/or genera difficult to differentiate (such as Chabertia ovina and Oesophagostomum columbianum), is to estimate the proportion of the larval sheath tail extension comprising a terminal thin, whip-like filament. For the experienced person, it is seldom necessary to measure more than one or two sheath tail extensions of L3 in a mixed culture, because the identity of most of the remaining L3 can thereafter be estimated in relation to those measured, without having to take further measurements. The aim of this article was to present the novel approach in the form of a working guide for routine use in the laboratory. To facilitate identification, figures and a separate organogram for each of small ruminants and cattle have been added to illustrate the distinguishing features of the common L3.

<span>In 2004, a new concept was introduced for simplifying identification of larvae of the common nematodes of cattle, sheep and goats that comprises estimates of the lengths of the sheath tail extensions of infective third-stage larvae (L</span>₃<span>) of each genus and/or species to that of </span><em>Trichostrongylus</em><span> spp., instead of having to be dependent only on measurements in micrometre. For example, if the mean length of the sheath tail extension (the extension of the sheath caudad, beyond the caudal tip of the larva) of </span><em>Trichostrongylus colubriformis </em><span>and</span><em> Trichostrongylus axei</em><span> is assumed to be ‘X’, then that of</span><em>Haemonchus contortus</em><span> is 2.0–2.7 ‘X’ – a difference that is not difficult to estimate. An additional new approach suggested now, particularly for L</span>₃<span> of species and/or genera difficult to differentiate (such as </span><em>Chabertia ovina</em><span> and </span><em>Oesophagostomum columbianum</em><span>), is to estimate the proportion of the larval sheath tail extension comprising a terminal thin, whip-like filament. For the experienced person, it is seldom necessary to measure more than one or two sheath tail extensions of L</span>₃<span> in a mixed culture, because the identity of most of the remaining L</span>₃<span> can thereafter be estimated in relation to those measured, without having to take further measurements. The aim of this article was to present the novel approach in the form of a working guide for routine use in the laboratory. To facilitate identification, figures and a separate organogram for each of small ruminants and cattle have been added to illustrate the distinguishing features of the common L</span>₃<span>.</span><br />

A molecular study was undertaken to detect Theileria ovis, Theileria lestoquardi and Theileria annulatain sheep and tick vectors. Investigation was conducted from 2010 to 2011 in the south of Khorasan Razavi Province, Iran. A total of 150 blood samples were collected from 30 different sheep flocks. In addition, ixodid ticks were sampled from the same flocks. The stained blood smears were microscopically examined for the presence of piroplasms and a semi-nested polymerase chain reaction-restriction (PCR) was used for subsequent molecular speciation. Salivary glands were isolated from the ticks and subsequently analysed by semi-nested PCR. polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to differentiate between T. lestoquardi and T. annulata from PCR-positive samples. Theileria species infection was microscopically detected in 18.6% of blood smears. The presence of T. ovis and T. lestoquardi or T. annulata was detected by semi-nested PCR in 58.6% and 6.6% of blood samples respectively. In total, 169 ixodid ticks were collected from different areas of the province. The most prevalent ticks were Rhipicephalus turanicus (n = 155; 91.7% of the total), followed by Hyalomma anatolicum anatolicum (n = 8; 4.7%) and Hyalomma marginatum turanicum (n = 6; 3.5%). From an organ pooling of 33 ticks, three pools of salivary glands from R. turanicus were positive for Theileria species by semi-nested PCR. Of the three R. turanicus samples testing positive for Theileria species, two (6.1%) were positive for T. ovis and one (3.0%) for T. lestoquardi or T. annulata. Amongst the 11 PCR-positive samples for T. lestoquardi or T. annulata, 10 were positive for T. lestoquardi and one sample was positive for both T. lestoquardi and T. annulata using PCR-RFLP. The results also demonstrated that PCR-RFLP could be used for the detection of T. ovis. Based on the results, it can be concluded that T. ovis has a higher prevalence than T. lestoquardi, and that R. turanicus could be a possible vector for T. ovis and T. lestoquardi. Finally, the PCR-RFLP based on Msp1 restriction enzyme is a simple method for differentiation of Theileria species in sheep and ixodid ticks.

A molecular study was undertaken to detect Theileria ovis, Theileria lestoquardi and Theileria annulatain sheep and tick vectors. Investigation was conducted from 2010 to 2011 in the south of Khorasan Razavi Province, Iran. A total of 150 blood samples were collected from 30 different sheep flocks. In addition, ixodid ticks were sampled from the same flocks. The stained blood smears were microscopically examined for the presence of piroplasms and a semi-nested polymerase chain reaction-restriction (PCR) was used for subsequent molecular speciation. Salivary glands were isolated from the ticks and subsequently analysed by semi-nested PCR. polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to differentiate between T. lestoquardi and T. annulata from PCR-positive samples. Theileria species infection was microscopically detected in 18.6% of blood smears. The presence of T. ovis and T. lestoquardi or T. annulata was detected by semi-nested PCR in 58.6% and 6.6% of blood samples respectively. In total, 169 ixodid ticks were collected from different areas of the province. The most prevalent ticks were Rhipicephalus turanicus (n = 155; 91.7% of the total), followed by Hyalomma anatolicum anatolicum (n = 8; 4.7%) and Hyalomma marginatum turanicum (n = 6; 3.5%). From an organ pooling of 33 ticks, three pools of salivary glands from R. turanicus were positive for Theileria species by semi-nested PCR. Of the three R. turanicus samples testing positive for Theileria species, two (6.1%) were positive for T. ovis and one (3.0%) for T. lestoquardi or T. annulata. Amongst the 11 PCR-positive samples for T. lestoquardi or T. annulata, 10 were positive for T. lestoquardi and one sample was positive for both T. lestoquardi and T. annulata using PCR-RFLP. The results also demonstrated that PCR-RFLP could be used for the detection of T. ovis. Based on the results, it can be concluded that T. ovis has a higher prevalence than T. lestoquardi, and that R. turanicus could be a possible vector for T. ovis and T. lestoquardi. Finally, the PCR-RFLP based on Msp1 restriction enzyme is a simple method for differentiation of Theileria species in sheep and ixodid ticks.

A cross-sectional study was conducted to determine the prevalence of sub-clinical and clinical mastitis and the associated factors in cows from selected smallholder dairy farms in Zimbabwe. Physical examinations were conducted on all lactating cows for evidence of signs of clinical mastitis. Composite milk samples were collected from all lactating cows for bacterial culture and somatic cell counting. Cows were categorised as clinical if they exhibited clinical features of mastitis, or sub-clinical if no apparent signs were present but they had a positive bacterial isolation and a somatic cell count of at least 300 x 103 cells/mL. Farm-level factors were obtained through a structured questionnaire. The association of mastitis and animal- and herd-level factors were analysed using logistic regression. A total of 584 animals from 73 farms were tested. Overall, 21.1%(123/584) had mastitis, 16.3%(95/584) had sub-clinical mastitis and 4.8% (28/584) had clinical mastitis. Herd-level prevalence was 49.3%. Coagulase-negative staphylococci (27.6%),  Escherichia coli (25.2%),  Staphylococcus aureus(16.3%), Klebsiella spp. (15.5%) and Streptococcus spp. (1.6%) were the most common isolates. In individual cows, pure dairy herds (OR = 6.3) and dairy crosses (OR = 3.1) were more likely to have mastitis compared to Mashona cows. Farms that used pre-milking teat dipping were associated with reduced mastitis prevalence. Further research is needed on the prevalence of mastitis and a comparison of data for both smallholder and commercial dairy farms in all regions of Zimbabwe should be undertaken.

A cross-sectional study was conducted to determine the prevalence of sub-clinical and clinical mastitis and the associated factors in cows from selected smallholder dairy farms in Zimbabwe. Physical examinations were conducted on all lactating cows for evidence of signs of clinical mastitis. Composite milk samples were collected from all lactating cows for bacterial culture and somatic cell counting. Cows were categorised as clinical if they exhibited clinical features of mastitis, or sub-clinical if no apparent signs were present but they had a positive bacterial isolation and a somatic cell count of at least 300 x 103 cells/mL. Farm-level factors were obtained through a structured questionnaire. The association of mastitis and animal- and herd-level factors were analysed using logistic regression. A total of 584 animals from 73 farms were tested. Overall, 21.1%(123/584) had mastitis, 16.3%(95/584) had sub-clinical mastitis and 4.8% (28/584) had clinical mastitis. Herd-level prevalence was 49.3%. Coagulase-negative staphylococci (27.6%),  Escherichia coli (25.2%),  Staphylococcus aureus(16.3%), Klebsiella spp. (15.5%) and Streptococcus spp. (1.6%) were the most common isolates. In individual cows, pure dairy herds (OR = 6.3) and dairy crosses (OR = 3.1) were more likely to have mastitis compared to Mashona cows. Farms that used pre-milking teat dipping were associated with reduced mastitis prevalence. Further research is needed on the prevalence of mastitis and a comparison of data for both smallholder and commercial dairy farms in all regions of Zimbabwe should be undertaken.

The purpose of this study was to explore the audits, quality assurance (QA) programmes and legal frameworks used in selected abattoirs in Zimbabwe and slaughterhouse workers’ perceptions on their effectiveness. Data on slaughterhouse workers was gathered through a self-completed questionnaire and additional information was obtained from slaughterhouse and government records. External auditing was conducted mainly by the Department of Veterinary Public Health with little contribution from third parties. Internal auditing was restricted to export abattoirs. The checklist used on auditing lacked objective assessment criteria and respondents cited several faults in the current audit system. Most respondents (50.0%) knew the purposes and benefits of audit and QA inspections. All export abattoirs had QA programmes such as hazard analysis critical control point and ISO 9001 (a standard used to certify businesses’ quality management systems) but their implementation varied from minimal to nil. The main regulatory defect observed was lack of requirements for a QA programme. Audit and quality assurance communications to the selected abattoirs revealed a variety of non-compliances with most respondents revealing that corrective actions to audit (84.3%) and quality assurance (92.3%) shortfalls were not done. A high percentage of respondents indicated that training on quality (76.8%) and regulations (69.8%) was critical. Thus, it is imperative that these abattoirs develop a food safety management system comprising of QA programmes, a microbial assessment scheme, regulatory compliance, standard operating procedures, internal and external auditing and training of workers.

The purpose of this study was to explore the audits, quality assurance (QA) programmes and legal frameworks used in selected abattoirs in Zimbabwe and slaughterhouse workers’ perceptions on their effectiveness. Data on slaughterhouse workers was gathered through a self-completed questionnaire and additional information was obtained from slaughterhouse and government records. External auditing was conducted mainly by the Department of Veterinary Public Health with little contribution from third parties. Internal auditing was restricted to export abattoirs. The checklist used on auditing lacked objective assessment criteria and respondents cited several faults in the current audit system. Most respondents (>50.0%) knew the purposes and benefits of audit and QA inspections. All export abattoirs had QA programmes such as hazard analysis critical control point and ISO 9001 (a standard used to certify businesses’ quality management systems) but their implementation varied from minimal to nil. The main regulatory defect observed was lack of requirements for a QA programme. Audit and quality assurance communications to the selected abattoirs revealed a variety of non-compliances with most respondents revealing that corrective actions to audit (84.3%) and quality assurance (92.3%) shortfalls were not done. A high percentage of respondents indicated that training on quality (76.8%) and regulations (69.8%) was critical. Thus, it is imperative that these abattoirs develop a food safety management system comprising of QA programmes, a microbial assessment scheme, regulatory compliance, standard operating procedures, internal and external auditing and training of workers.

The apxIC genes of the Actinobacillus pleuropneumoniae serovar 5 (SC-1), encoding the ApxIactivating proteins, was deleted by a method involving sucrose counter-selection. In this study, a mutant strain of A. pleuropneumoniae (SC-1) was constructed and named DapxIC/ ompP2. The mutant strain contained foreign DNA in the deletion site of ompP2 gene of Haemophilus parasuis. It showed no haemolytic activity and lower virulence of cytotoxicity in mice compared with the parent strain, and its safety and immunogenicity were also evaluated in mice. The LD50 data shown that the mutant strain was attenuated 30-fold, compared with the parent strain (LD50 of the mutant strain and parent strain in mice were determined to be 1.0 × 107 CFU and 3.5 × 105 CFU respectively). The mutant strain that was attenuated could secrete inactivated ApxIA RTX toxins with complete antigenicity and could be used as a candidate live vaccine strain against infections of A. pleuropneumoniae and H. parasuis.

The apxIC genes of the <em>Actinobacillus pleuropneumoniae</em> serovar 5 (SC-1), encoding the ApxIactivating proteins, was deleted by a method involving sucrose counter-selection. In this study, a mutant strain of <em>A. pleuropneumoniae</em> (SC-1) was constructed and named DapxIC/ ompP2. The mutant strain contained foreign DNA in the deletion site of ompP2 gene of <em>Haemophilus parasuis</em>. It showed no haemolytic activity and lower virulence of cytotoxicity in mice compared with the parent strain, and its safety and immunogenicity were also evaluated in mice. The LD₅₀ data shown that the mutant strain was attenuated 30-fold, compared with the parent strain (LD₅₀ of the mutant strain and parent strain in mice were determined to be 1.0 × 10⁷ CFU and 3.5 × 10⁵ CFU respectively). The mutant strain that was attenuated could secrete inactivated ApxIA RTX toxins with complete antigenicity and could be used as a candidate live vaccine strain against infections of <em>A. pleuropneumoniae</em> and <em>H. parasuis.</em>

The study investigated the effect of various doses of carbendazim on the morphology of the magnum of the Japanese quail. No morphological changes were observed in the magnum in birds treated with carbendazim at doses of 25 mg/kg and 100 mg/kg bodyweight. A carbendazim dose of 400 mg/kg bodyweight was the lowest dose which caused morphological changes in the magnum. Histologically, carbendazim caused pyknosis and glandular atrophy in the magnum mucosa. Carbendazim also caused significant decreases in the height of the mucosal folds, epithelial height, glandular width and glandular luminal diameter at 400 mg/kg and 800 mg/kg (p 0.05). At ultrastructural level, dose-dependent deciliation was observed. Pyknotic nuclei, dilated cisternae of rough endoplasmic reticulum, swollen mitochondria, numerous vacuoles and lysosomes in the luminal and glandular epithelia were identified. The observed degenerative changes could be due to cytoskeletal disruption caused by carbendazim toxicity. Degeneration of the luminal and glandular cells in the magnum pose a potential threat to the egg production and reproduction of exposed birds.

The study investigated the effect of various doses of carbendazim on the morphology of the magnum of the Japanese quail. No morphological changes were observed in the magnum in birds treated with carbendazim at doses of 25 mg/kg and 100 mg/kg bodyweight. A carbendazim dose of 400 mg/kg bodyweight was the lowest dose which caused morphological changes in the magnum. Histologically, carbendazim caused pyknosis and glandular atrophy in the magnum mucosa. Carbendazim also caused significant decreases in the height of the mucosal folds, epithelial height, glandular width and glandular luminal diameter at 400 mg/kg and 800 mg/kg (p < 0.05). At ultrastructural level, dose-dependent deciliation was observed. Pyknotic nuclei, dilated cisternae of rough endoplasmic reticulum, swollen mitochondria, numerous vacuoles and lysosomes in the luminal and glandular epithelia were identified. The observed degenerative changes could be due to cytoskeletal disruption caused by carbendazim toxicity. Degeneration of the luminal and glandular cells in the magnum pose a potential threat to the egg production and reproduction of exposed birds.

The metacercarial (larval) stages of diplostomid digeneans are known to inhabit freshwater fish, causing tissue damage in the process. Due to their widespread diversity, little is known about their life cycle. The classification of these parasitic stages to the species level using only the morphology is very challenging due to the lack of genitalia; they are regarded to be the most important structures in the identification of these organisms. In this study, additional morphological information through light and scanning electron microscopy is given for two different diplostomids found in the cranial cavity of Clarias gariepinus and the vitreous chambers of Tilapia sparrmanii and Pseudocrenilabrus philander. The diplostomid metacercaria inhabiting the cranial cavity of Clarias gariepinus was morphologically identified as Diplostomulum (Tylodelphys) mashonenseand an unknown metacercaria of the genus Diplostomumwas found in the vitreous chambers of Pseudocrenilabrus philander and Tilapia sparrmanii. Both parasitic species’ 28S recombinant deoxyribonucleic acid genomic regions were successfully amplified using Dig 125/1500R primer pairs. The assay yielded a product of approximately 1300 base pairs as seen on the gel images. There were 14 nucleotide differences over the entire analysed sequences resulting in a 1.1% (14/1273) nucleotide difference. In line with the morphological characteristics of these parasites, there seemed to be a slight difference in their genetic makeup. The application of molecular techniques on digenetic trematodes seems very promising and may yield great potential in future descriptions of morphologically similar parasitic species.

The metacercarial (larval) stages of diplostomid digeneans are known to inhabit freshwater fish, causing tissue damage in the process. Due to their widespread diversity, little is known about their life cycle. The classification of these parasitic stages to the species level using only the morphology is very challenging due to the lack of genitalia; they are regarded to be the most important structures in the identification of these organisms. In this study, additional morphological information through light and scanning electron microscopy is given for two different diplostomids found in the cranial cavity of Clarias gariepinus and the vitreous chambers of Tilapia sparrmanii and Pseudocrenilabrus philander. The diplostomid metacercaria inhabiting the cranial cavity of Clarias gariepinus was morphologically identified as Diplostomulum (Tylodelphys) mashonenseand an unknown metacercaria of the genus Diplostomumwas found in the vitreous chambers of Pseudocrenilabrus philander and Tilapia sparrmanii. Both parasitic species’ 28S recombinant deoxyribonucleic acid genomic regions were successfully amplified using Dig 125/1500R primer pairs. The assay yielded a product of approximately 1300 base pairs as seen on the gel images. There were 14 nucleotide differences over the entire analysed sequences resulting in a 1.1% (14/1273) nucleotide difference. In line with the morphological characteristics of these parasites, there seemed to be a slight difference in their genetic makeup. The application of molecular techniques on digenetic trematodes seems very promising and may yield great potential in future descriptions of morphologically similar parasitic species.