Identification and partial sequencing of a crocodile poxvirus associated with deeply penetrating skin lesions in farmed Nile crocodiles, Crocodylus niloticus.

When large numbers of crocodile skins were downgraded because of the presence of small pin prick-like holes, collapsed epidermal cysts were found deep in the dermis of juvenile crocodiles while forming cysts were observed in hatchlings. Histopathology of these forming cysts showed the presence of intracytoplasmic inclusions in proliferating and ballooning epidermal cells. Pox virions were seen in electron microscope preparations made from the scabs of such early lesions. The partial sequencing of virus material from scrapings of these lesions and comparison of it with the published sequence of crocodile poxvirus showed the virus associated with the deep lesions to be closely related, but different. To differentiate between the two forms of crocodile pox infection it is suggested that the previously known form should be called "classical crocodile pox" and the newly discovered form "atypical crocodile pox". The application of strict hygiene measures brought about a decline in the percentage of downgraded skins.

An outbreak of chlamydiosis in farmed Indopacific crocodiles (Crocodylus porosus).

An outbreak of chlamydiosis was diagnosed in hatchling and juvenile Indopacific crocodiles (Crocodylus porosus) on a crocodile farm in Papua New Guinea. The outbreak was characterised by high mortality with hepatitis and exudative conjunctivitis. The agent appears to have been introduced with live wild-caught crocodiles, which are purchased routinely by the farm. Improved quarantine procedures and treatment with tetracycline led to a rapid reduction of losses on the farm.

Diseases of farmed crocodiles and ostriches.

Crocodiles and ostriches are very sensitive to stress, and the ideal conditions for intensive rearing have not yet been established. Consequently, mortality is often directly linked to conditions on the farm. Crocodile and caiman pox, adenoviral hepatitis, mycoplasmosis, chlamydiosis and coccidiosis are crocodile-specific infections with reservoirs in wild populations and adult wild-caught breeding stock. Other important conditions are salmonellosis, non-specific septicaemia, trichinellosis, the nutritional diseases osteomalacia, fat necrosis and gout, as well as winter sores. The only ostrich-specific transmissible disease is libyostrongylosis. Other important conditions are Newcastle disease, avian influenza, fading chick syndrome, tibiotarsal rotation and enteritis. No cases of coccidiosis in ostriches have ever been confirmed.

Multifactorial mortality in bongos and other wild ungulates in the north of the Congo Republic.

Wildlife mortality involving bongos, Tragelaphus eurycerus, and other ungulates was investigated in the north of the Congo Republic in 1997. Four bongos, one forest buffalo, Syncerus caffer nanus, and one domestic sheep were examined and sampled. Although an outbreak of rinderpest had been suspected, it was found that the animals, which had been weakened by an Elaeophora sagitta infection and possibly also by adverse climatic conditions, had been exsanguinated and driven to exhaustion by an unusual plague of Stomoxys omega.

Aerobic intestinal flora of wild-caught African dwarf crocodiles Osteolaemus tetraspis.

Intestinal contents were collected from wild-caught African dwarf crocodiles (Osteolaemus tetraspis) in 1993 and 1995 which were slaughtered at urban markets in the Congo Republic. The samples were kept frozen and brought back to Onderstepoort for aerobic culture. Out of 29 specimens, 33 species of bacteria and 20 species of fungi were isolated. The bacteria included three isolates of Salmonella and eight isolates of Escherichia coli, most of the latter being rough strains. The flora of individual specimens contained 1-5 bacterial and 0-5 fungal species. Neither Aeromonas hydrophila nor Edwardsiella tarda were isolated from any of the samples.

Public health risks of ostrich and crocodile meat.

This paper discusses the infectious agents and chemical substances potentially capable of contaminating the meat of ostriches and crocodiles and which thus pose a danger to human handlers and consumers. For ostrich meat, there is no danger from Crimean-Congo haemorrhagic fever or spongiform encephalopathy. Contamination of ostrich meat with salmonellae, chlamydia, pasteurellae, mycobacteria and erysipelas might be possible, but has never been reported. No parasites are known which could be transmitted through ostrich meat to human consumers. Residues from growth hormones, antibiotics and acaricides are potential public health hazards. For crocodile meat, there is a distinct possibility of contamination with salmonellae, depending on housing, feed, slaughter technique and hygiene practices under which the animal is reared. Chlamydial infections are common on some crocodile farms in southern Africa. Mycobacteriosis is extremely rare. Tapeworm cysts have been found in crocodile meat in two cases only. Trichinellosis has been reported on several crocodile farms in Zimbabwe. A generalised coccidiosis with invasion of organs and tissues has been seen in several species of crocodiles, but should present no danger to consumers.

Animal health risks associated with ostrich products.

Five diseases recorded in ostriches are regarded as posing a potential animal health threat to meat-importing countries. Newcastle disease causes an atypically low mortality in ostriches: infected birds display typical nervous symptoms but no pathognomonic lesions which could be detected during post-mortem inspection. The vaccination of feedlot birds and a thorough ante-mortem examination are regarded as necessary precautions to ensure virus carriers are not among those animals destined for slaughter and subsequent export. Avian influenza produces clinical depression and lesions can be detected at post-mortem examination. Borna disease appears to affect mainly younger birds, and the virus is probably not present in the meat of affected birds. Finally, there is little evidence to suggest that ostriches could play a role in the epidemiology of transmissible spongiform encephalopathies. Cases of anthrax are extremely rare. The importation of deboned ostrich meat reduces the risk of infected scraps being fed to susceptible animals.

Salmonella isolated from crocodiles and other reptiles during the period 1985-1994 in South Africa.

Over a 10-year period, 173 isolates of Salmonella were obtained during routine isolation from reptiles. Of the 173 isolates, 92 different Salmonella serovars were identified. Of them, 61 (66%) belonged to subspecies I, nine to subspecies II and 21 to subspecies III (IIIa and IIIb), and one to subspecies IV. The majority of isolates were from farmed Nile crocodiles (145), three from wild-caught African dwarf crocodiles, 11 from captive snakes, 13 from lizards and one from a tortoise. The isolates from the tortoise and lizards were subspecies I isolates (Zaire and Tsevie, respectively). Of the snakes, nine isolates were S.III. The serovars isolated most often from the crocodiles were of subspecies I (32 serovars). Eight were from subspecies II, seven from subspecies III and one from subspecies IV. The most frequently identified serovars were Typhimurium (seven), Tsevie (six), Duval (six), Schwerin (six), Tinda (six), and Tallahassee (six). On two commercial crocodile breeding farms that had experienced ongoing problems for about two years, many isolates of Salmonella were made. Some of these serovars were isolated more than once, and also months apart. No single Salmonella serovar predominated, nor did a single pathological condition. These salmonellas were predominantly of subspecies I.

Host range, survival in dead hosts, cryopreservation, periodicity and morphology of Plasmodium durae Herman in experimental infections.

In experimental infections, fowl, duck, guineafowl and canary were refractory to Plasmodium durae, which in Japanese quail produced low and transient infections, but a high and long-lasting parasitaemia in a Lady Amherst pheasant. Heart, blood and brain of dead hosts injected into turkeys, allowed the recovery and further passaging of the live parasite. This technique could be useful for the recovery of malaria parasites from suspect postmortem material. Intravenous infection produced parasitaemias in chicken and turkey embryos, while attempts at altantoic-sac infections of chicken embryos were unsuccessful. A certain degree of periodicity of schizogony was demonstrated. The South African isolates of P. durae had smaller schizonts than those described from East and West Africa, with 2-14 merozoites (mostly four). Some strains did not produce mature gametocytes in the experimental hosts. Exoerythrocytic schizonts of P. durae are depicted in this paper for the first time.

Pentastomid parasites of the family Sebekidae Fain, 1961 in west African dwarf crocodiles Osteolaemus tetraspis Cope, 1851 from the Congo, with a description of Alofia parva n. sp.

The lungs and viscera of 23 dwarf crocodiles (Osteolaemus tetraspis) obtained from markets in Brazzaville, were examined for pentastomid infection. Twenty-one animals were infected and harboured a total of 82 pentastomids, all belonging to the family Sebekidae and representing at least two genera and three species. Sebekia okavangoensis Riley & Huchzermeyer, was present in the body cavity and lungs; the other two species were restricted to the lungs. Alofia parva n.sp. (14 female female; 10 male male) was unusual in that the fulcrum supporting the anterior hooks carried a cowl-like extension. The remaining species, provisionally allocated to the genus Sebekia, could not be classified to the generic level with certainty.

Concurrent infection with Clostridium and Plasmodium in a captive king penguin Aptenodytes patagonicus.

Concurrent infection with Plasmodium relictum and Clostridium perfringens Type B was diagnosed in a king penguin (Aptenodytes patagonicus) that died in the National Zoological Gardens, Pretoria. Macro- and microscopic pathological changes were mainly due to C. perfringens. The relative significance of the two pathogens is discussed.

Hepatitis in farmed hatchling Nile crocodiles (Crocodylus niloticus) due to chlamydial infection.

An investigation into the cause of acute mortality in farmed hatchling crocodiles Crocodylus niloticus led to the isolation of chlamydia from the livers of affected animals. Prominent pathological finds were acute hepatitis with intracellular chlamydial colonies and generalized oedema. A chlamydia presumed to be C. psittaci was isolated from livers of affected hatchlings. Mortality subsided after treatment with oxytetracycline. This disease is now recognized as being a major problem on crocodile farms in Zimbabwe.

Thymic necrosis in slaughtered Nile crocodiles.

Foci of necrosis with formation of heterophilic granulomas in the medullary region of the thymus were found in apparently normal slaughtered crocodiles from 4 South African crocodile farms. The comparative pathology of these lesions is discussed. From these preliminary results it may be assumed that thymic necrosis occurs commonly in intensively reared slaughter crocodiles. The cause of this condition, however, remains obscure.

Pathogenicity and chemotherapy of Plasmodium durae in experimentally infected domestic turkeys.

Only 3 out of 8 South African isolates of Plasmodium durae used in 524 turkeys in 161 passages caused approximately 50% mortality, a further 3 produced approximately 10% mortality while 2 were found to be apathogenic. Exoerythrocytic schizonts were the main pathogenic stage. In most survivors the effect on mass gains was minimal. Twelve drugs currently available for use in poultry, as well as chloroquin phosphate, were tested for their activity against experimental infections with Plasmodium durae in domestic turkeys. While chloroquin phosphate showed a certain degree of effectivity, Amprolium, Amprolium + Ethopabate, Maduramycin, Toltrazuril, Metronidazole, Furazolidone, Enrofloxacin and Sulfamethoxypyridazine + Trimethoprim were ineffective. Halofuginone and Penta-Sulfa at a high dose had some protective effect. At high doses Sulfachloropyrazine protected from mortality without affecting the parasitaemia, while Sulfamonomethoxine suppressed parasitaemia without entirely protecting from mortality. From these data it is concluded that Halofuginone has a potential as possible chemoprophylactic. While a combination of Sulfamonomethoxine and Sulfachloropyrazine could be used in the treatment of outbreaks in the field.

A host-parasite list of the haematozoa of domestic poultry in sub-Saharan Africa and the isolation of Plasmodium durae Herman from turkeys and francolins in South Africa.

An annotated host-parasite list of the blood parasites of domestic poultry in sub-Saharan Africa is presented. This list contains the haematozoa found in domestic waterfowl (ducks, geese and muscovies) and phasianids (turkey, fowl and peafowl). In South Africa Plasmodium durae was isolated from 4 out of 8 backyard turkeys, from 3 out of 26 Swainson's francolins and from 1 redwing francolin, but not from 20 helmeted guineafowls and 9 greywing francolins. This points at Swainson's and redwing francolins as being the main natural hosts of P. durae in South Africa. The increase in the period of prepatency after intramuscular subinoculation as compared with the intravenous route was found to correspond to that of a 1,000 fold dilution of an intravenous inoculum of parasitized blood. This delay was not due to an intervening cycle of exoerythrocytic schizogony, but to large numbers of the injected erythrocytes apparently not finding their way into the circulation of the new host.