Bacterial enteritis in ostrich (Struthio Camelus) chicks in the Western Cape Province, South Africa.

Ostrich (Struthio camelus) chicks less than 3 mo age are observed to experience a high mortality rate that is often associated with enteritis. This study was undertaken to investigate the infectious bacteria implicated in ostrich chick enteritis. Postmortems were performed on 122 ostrich chicks aged from 1 d to 3 mo and intestinal samples were subjected to bacterial culture. Bacterial isolates were typed by PCR and serotyping. Escherichia coli (E. coli; 49%) was the most frequently isolated from the samples followed by Clostridium perfringens (C. perfringens; 20%), Enterococcus spp. (16%), and Salmonella spp. (7%). Of the E. coli, 39% were categorized as enteropathogenic E. coli, 4% enterotoxigenic E. coli, and no enterohaemorrhagic E. coli were found. The majority (93%) of C. perfringens was Type A and only 7% was Type E. C. perfringens Types B through D were not present. The netB gene that encodes NetB toxin was identified from 16% of the C. perfringens isolated. All the C. perfringens Type E harbored the netB gene and just 10% of the C. perfringens Type A had this gene. Three Salmonella serotypes were identified: Salmonella Muenchen (S. Muenchen; 80%), S. Hayindongo (13%), and S. Othmarschen (7%). The indication is that the cause of enteritis in ostrich chicks is bacterial-involving: enteropathogenic E. coli and enterotoxigenic E. coli; C. perfringens Types A and E (with the possible influence of netB gene); and S. Muenchen, S. Hayindongo, and S. Othmarschen.

Identification of three novel mycoplasma species from ostriches in South Africa.

Mycoplasmas have been implicated in certain clinical syndromes in ostriches and are associated with upper respiratory tract infections. As these infections result in production losses, they are of considerable economic importance to the South African ostrich industry. Although poultry mycoplasmas have been shown to infect ostriches, the existence of unique ostrich-specific mycoplasmas has been suggested. In this study, mycoplasmas were isolated from ostriches in the Klein Karoo, Central Karoo and Garden Route areas of the Western and Northern Cape Provinces of South Africa and identified using 16S rRNA gene sequencing. These sequences indicated that ostriches in these areas carry three unique mycoplasmas and were not infected with chicken mycoplasmas. Phylogenetic analysis of the 16S rRNA sequences of the three isolated ostrich mycoplasmas showed them to be quite divergent and to fall into two distinct phylogenetic groupings. Unique sequences within the 16S rRNA gene of the ostrich mycoplasmas were subsequently used for the development of specific primers for the detection and diagnosis of mycoplasma infections in ostriches. Chickens kept in close proximity to infected ostriches were not infected with these ostrich mycoplasmas.

Antibody responses to La Sota strain vaccines of Newcastle disease virus in ostriches (Struthio camelus) as detected by enzyme-link ed immunosorbent assay.

Because of the fact that South Africa is a Newcastle disease virus (NDV)-endemic country, major concerns exist that the export of ostrich meat could transmit velogenic strains of this disease. The ability to transmit the virus could be reduced by effective vaccination of South African ostriches. In this study, two vaccination trials were conducted to assess serum antibody production in response to vaccination with La Sota strain NDV vaccines. To this end, a commercially available chicken anti-NDV enzyme-linked immunosorbent assay (ELISA) was modified for the detection of anti-NDV antibodies in ostrich serum. The results obtained with this ELISA were verified by comparison with an indirect ELISA. In the first trial, ostriches were immunized subcutaneously four times with different volumes of an inactivated vaccine and their immune response was determined from 2.5 mo up to the ideal slaughter age of 14 mo. Results indicated that ostriches responded in a dose-dependent manner and gave support for the vaccination schedule currently recommended to South African farmers. In a second trial, immunization by eyedrop with a live La Sota vaccine of 5-wk-old ostriches did not elicit a humoral immune response. The results indicate that it is highly unlikely that ostriches that have been vaccinated according to the recommended vaccination schedule can transmit the virus.

Experimental infection of ostriches with Crimean-Congo haemorrhagic fever virus.

Following the occurrence of an outbreak of Crimean-Congo haemorrhagic fever (CCHF) among workers at an ostrich abattoir in South Africa in 1996, 9 susceptible young ostriches were infected subcutaneously with the virus in order to study the nature of the infection which they undergo. The ostriches developed viraemia which was demonstrable on days 1-4 following infection, with a maximum intensity of 4.0 log10 mouse intracerebral LD50/ml being recorded on day 2 in 1 of the birds. Virus was detectable in visceral organs such as spleen, liver and kidney up to day 5 post-inoculation, 1 day after it could no longer be found in blood. No infective virus was detected in samples of muscle, but viral nucleic acid was detected by reverse transcription-polymerase chain reaction in muscle from a bird sacrificed on day 3 following infection. It was concluded that the occurrence of infection in ostriches at abattoirs could be prevented by keeping the birds free of ticks for 14 days before slaughter.

Pharmacokinetics of clenbuterol in the ostrich.

The aim of this study was to investigate the pharmacokinetics of clenbuterol in the ostrich as no such data is available. Clenbuterol (2 mg) was given as a single oral dose to nine ostriches. Blood samples were collected over a period of 96 h after administration and urine for a period of 5 d. Plasma and urine samples were frozen at -20 degrees C pending analysis. Clenbuterol was quantified using a gas chromatograph-mass selective detector. The method for quantification of clenbuterol in plasma was validated by analysing spiked quality control samples at different concentrations. The limit of quantification was determined to be 0.75 ng ml-1 with an absolute recovery of more than 80%. The geometric mean maximum plasma clenbuterol concentration was 4.40 ng ml-1 with 3.0 h as the median time for maximum concentration. The plasma elimination half-life was 19.7 h. The clenbuterol concentration was above 0.75 ng ml-1 in plasma for 48 h and above 1.0 ng ml-1 in urine for 5 d. These data can be useful in residue analysis for clenbuterol in ostriches.

Sperm-storage tubules in the vagina of the ostrich (Struthio camelus).

Sperm-storage tubules have been described in a number of species of birds. The presence of these tubules in the Rhea has been mentioned, but no description of these structures in ratites is available. The purpose of this study was to determine the presence and morphology of sperm-storage tubules in the vagina of the ostrich. The study was performed with the use of conventional light- and electron-microscopic techniques. Sperm-storage tubules were located in a 200-mm-wide band of the vagina adjacent to the utero-vaginal junction. The tubules were mostly branched and slightly coiled and lined by columnar epithelial cells. The cells contained a basal nucleus and displayed extensive apical junctional complexes. TEM revealed sperm in all the tubules examined.

Evidence for cryptosporidial infection as a cause of prolapse of the phallus and cloaca in ostrich chicks (Struthio camelus).

Cloacas of male ostrich chicks that had suffered prolapse of the phallus and cloaca were compared with cloacas of normal ostrich chicks of both sexes from the same area. Heavy infection of the cloacal and bursal tissue with Cryptosporidium sp. was present in all the cases of prolapse, while no cryptosporidia were observed in the normal chicks. Histopathological lesions as described in cryptosporidial infection in other species were present in the infected cloacas. These included loss of the microvillous border and epithelial hyperplasia and degeneration, which was indicated ultrastructurally by vacuolation of the apical cytoplasm, swelling of organelles, and nuclear changes. It is suggested that these lesions, in combination with the anatomy of the male ostrich cloaca, may be responsible for prolapse of the phallus and cloaca.

Cardiomyopathy in ostriches (Struthio camelus) due to avocado (Persea americana var. guatemalensis) intoxication.

Nine out of 120 ostriches died from congestive heart failure within 96 h of ingesting avocado leaves and immature fruit in an avocado orchard containing Hass and Fuerte cultivars. Foliage and immature fruit from both cultivars dosed to ostriches (n = 4) and domestic hens (n = 8) resulted in severe cardiomyopathy in all the ostriches. In the hens, which had received a lower dose, milder lesions occurred. Macroscopically the intoxication in ostriches resulted in a severe anasarca of the neck and ventral body. The cardiomyopathy was characterised by degeneration and necrosis of myocytes, a marked infiltration of heterophils and in one case, early fibroplasia.

Serum- and bone-mineral status of ostriches with tibiotarsal rotation.

Tibiotarsal rotation in ostrich chicks is a serious problem that accounts for considerable financial loss to ostrich farmers. Serum- and bone-mineral analyses of 20 ostrich chicks with tibiotarsal rotation were compared with serum- and bone-mineral analyses of eight normal ostrich chicks of comparable age, sex and body mass, and raised under identical conditions. The serum-zinc values were significantly higher and the bone-calcium and phosphorus values significantly lower in the affected group than in the group of normal ostrich chicks. The results indicated poor mineralization of bone with subsequent reactive osteoid formation.

Avian pox in ostriches.

Nodular cutaneous and diphtheric oral lesions, resembling avian pox were observed in 2 flocks of young ostrich chicks. Typical eosinophilic intracytoplasmic inclusion bodies were seen in histological sections and a pox virus was isolated from the lesions. A commercial fowl pox vaccine was used to protect young ostriches in the field.

Prolapse of the phallus and cloaca in the ostrich (Struthio camelus).

The incidence of cloacal prolapse in ostrich chicks hatched and raised on the Oudtshoorn Experimental Farm during the 1992-1993 breeding season was investigated. The condition which occurred primarily in male chicks, affected 14.65% of the total number of chicks hatched. The mortality rate amongst chicks with cloacal prolapse was very high. Although the pathogenesis and aetiology of the condition is unknown, a species of Cryptosporidium was present in large numbers in affected cloacas. Treatment with systemic antibiotics was found to be effective in some cases.

The incidence of tibiotarsal rotation in the ostrich (Struthio camelus).

Abnormal lateral tibiotarsal rotation has been reported as one of many abnormalities affecting the pelvic appendicular skeleton of birds. In this study, lateral rotation of the tibiotarsus affected 89 out of 1,407 ostrich chicks between 2 weeks and 6 months of age raised at the Oudtshoorn Experimental Farm. There was no sexual preference, but the lesion affected the right pelvic limb almost exclusively and very rarely the left limb. Pelvic appendicular skeletal abnormalities make a significant contribution to mortalities in ostrich chicks.

Isolation of an influenza A virus from ostriches (Struthio camelus).

An influenza A virus of the H7 N1 subtype was isolated from young ostriches which died after developing a syndrome characterized by a green discolouration of the urine, weakness and signs of respiratory distress. Mortality varied, depending on the age of the ostriches, the presence of other infectious agents and the amount of stress to which they were exposed. Using the haemagglutination inhibition test, an amnestic response was recorded in ostriches which recovered from the disease. Pathogenicity tests indicated that the isolate was of low virulence for chickens.